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Author  |
Zhu, W.; Van Tendeloo, M.; Xie, Y.; Timmer, M.J.; Peng, L.; Vlaeminck, S.E. |
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Title |
Storage without nitrite or nitrate enables the long-term preservation of full-scale partial nitritation/anammox sludge |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
The science of the total environment |
Abbreviated Journal |
Sci Total Environ |
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Volume |
806 |
Issue |
3 |
Pages |
151330 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Bioaugmentation with summer harvested sludge during winter could compensate for bacterial activity loss but requires that sludge activity can be restored after storage. This study assesses the effect of temperature and redox adjustment during the storage over 180 days of partial nitritation/anammox (PN/A) granular resp. floccular sludge from potato processing resp. sludge reject water treatment. Anoxic storage conditions (in the presence of nitrite or nitrate and the absence of oxygen) resulted in a loss of 80-100% of the anammox bacteria (AnAOB) activity capacity at 20 degrees C and 4 degrees C, while anaerobic conditions (without oxygen, nitrite, and nitrate) lost only 45-63%. Storage at 20 degrees C was more cost-effective compared to 4 degrees C, and this was confirmed in the sludge reactivation experiment (20 CC). Furthermore, AnAOB activity correlated negatively with the electrical conductivity level (R-2 > 0.85, p < 0.05), so strong salinity increases should be avoided. No significant differences were found in the activity capacity of aerobic ammonia-oxidizing bacteria (AerAOB) under different storage conditions (p > 0.1). The relative abundance of dominant AnAOB (Candidatus Brocadia) and AerAOB genera (Nitrosomonas) remained constant in both sludges. In conclusion, preserving PN/A biomass without cooling and nitrite or nitrate addition proved to be a cost-effective strategy. (C) 2021 Elsevier B.V. All rights reserved. |
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Wos |
000740216300013 |
Publication Date |
2021-10-28 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0048-9697 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.8 |
Times cited |
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Open Access |
OpenAccess |
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Approved |
Most recent IF: 9.8 |
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Call Number |
UA @ admin @ c:irua:185447 |
Serial |
7213 |
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Author |
Zhu, W.; Van Tendeloo, M.; De Paepe, J.; Vlaeminck, S.E. |
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Title |
Comparison of typical nitrite oxidizing bacteria suppression strategies and the effect on nitrous oxide emissions in a biofilm reactor |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Bioresource technology |
Abbreviated Journal |
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Volume |
387 |
Issue |
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Pages |
129607-129609 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
In mainstream partial nitritation/anammox (PN/A), suppression of nitrite oxidizing bacteria (NOB) and mitigation of N2O emissions are two essential operational goals. The N2O emissions linked to three typical NOB suppression strategies were tested in a covered rotating biological contactor (RBC) biofilm system at 21 degrees C: (i) low dissolved oxygen (DO) concentrations, and treatments with (ii) free ammonia (FA), and (iii) free nitrous acids (FNA). Low emerged DO levels effectively minimized NOB activity and decreased N2O emissions, but NOB adaptation appeared after 200 days of operation. Further NOB suppression was successfully achieved by periodic (3 h per week) treatments with FA (29.3 & PLUSMN; 2.6 mg NH3-N L-1) or FNA (3.1 & PLUSMN; 0.3 mg HNO2-N L-1). FA treatment, however, promoted N2O emissions, while FNA did not affect these. Hence, biofilm PN/A should be operated at relatively low DO levels with periodic FNA treatment to maximize nitrogen removal efficiency while avoiding high greenhouse gas emissions. |
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001063180200001 |
Publication Date |
2023-08-05 |
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ISSN |
0960-8524 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.4 |
Times cited |
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Open Access |
Not_Open_Access: Available from 21.02.2024 |
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Notes |
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Approved |
Most recent IF: 11.4; 2023 IF: 5.651 |
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Call Number |
UA @ admin @ c:irua:199051 |
Serial |
8843 |
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Author |
Zhu, W.; Van Tendeloo, M.; Alloul, A.; Vlaeminck, S.E. |
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Title |
Towards mainstream partial nitritation/anammox in four seasons : feasibility of bioaugmentation with stored summer sludge for winter anammox assistance |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Bioresource technology |
Abbreviated Journal |
Bioresource Technol |
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Volume |
347 |
Issue |
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Pages |
126619-11 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
The strong effect of low temperatures on anammox challenges its mainstream application over the winter in temperate climates. Winter bioaugmentation with stored summer surplus sludge is a potential solution to guarantee sufficient nitrogen removal in winter. Firstly, the systems for which nitrogen removal deteriorated by the temperature decrease (25 °C → 20 °C) could be fully restored bioaugmenting with granules resp. flocs stored for 6 months at 118 resp. 220% of the initial biomass levels. Secondly, the reactivation of these stored sludges was tested in lower temperature systems (15.3 ± 0.4/10.4 ± 0.4 °C). Compared to the activity before storage, between 56% and 41% of the activity of granules was restored within one month, and 41%–32% for flocs. Additionally, 85–87% of granules and 50–53% of flocs were retained in the systems. After reactivation (15.3 ± 0.4/10.4 ± 0.4 °C), a more specialized community was formed (diversity decreased) with Candidatus Brocadia still dominant in terms of relative abundance. Capital and operating expenditures (CAPEX, OPEX) were negligible, representing only 0.19–0.36% of sewage treatment costs. |
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Wos |
000781730900001 |
Publication Date |
2021-12-25 |
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ISSN |
0960-8524 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 11.4 |
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Call Number |
UA @ admin @ c:irua:185210 |
Serial |
7220 |
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Author |
Zhu, W.; Van Tendeloo, M.; Alloul, A.; Vlaeminck, S.E. |
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Title |
Feasibility of a return-sludge nursery concept for mainstream anammox biostimulation : creating optimal conditions for anammox to recover and grow in a parallel tank |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Bioresource technology |
Abbreviated Journal |
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Volume |
385 |
Issue |
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Pages |
129359-12 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
To overcome limiting anammox activity under sewage treatment conditions, a return-sludge nursery concept is proposed. This concept involves blending sludge reject water treated with partial nitritation with mainstream effluent to increase the temperature, N levels, and electrical conductivity (EC) of the anammox nursery reactor, which sludge periodically passes through the return sludge line of the mainstream system. Various nursery frequencies were tested in two 2.5 L reactors, including 0.5-2 days of nursery treatment per 3.5-14 days of the total operation. Bioreactor experiments showed that nursery increased nitrogen removal rates during mainstream operation by 33-38%. The increased anammox activity can be partly (35-60%) explained by higher temperatures. Elevated EC, higher nitrogen concentrations, and a putative synergy and/or unknown factor were responsible for 15-16%, 12-14%, and 10-36%, respectively. A relatively stable microbial community was observed, dominated by a “Candidatus Brocadia” member. This new concept boosted activity and sludge growth, which may facilitate mainstream anammox implementations based on partial nitritation/anammox or partial nitrification/denitratation/anammox. |
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Wos |
001031586400001 |
Publication Date |
2023-06-19 |
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Edition |
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ISSN |
0960-8524 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
11.4 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 11.4; 2023 IF: 5.651 |
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Call Number |
UA @ admin @ c:irua:198259 |
Serial |
8866 |
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Author |
Zhu, W.; Li, J.; Wang, B.; Chen, G. |
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Title |
Enhancement of pollutants removal from saline wastewater through simultaneous anammox and denitrification (SAD) process with glycine betaine addition |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Bioresource Technology |
Abbreviated Journal |
Bioresource Technol |
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Volume |
315 |
Issue |
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Pages |
123784 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Enhanced pollutants removal from saline wastewater was investigated in simultaneous anammox and denitrification (SAD) process with glycine betaine (GB) addition. Long-term operation indicated the optimal GB dose was around 0.4 mM, which enhanced both anammox and denitrifying activity by 30% and 45%, respectively. The total nitrogen and organic removal rates were 0.38 +/- 0.2 kgN/m(3)/d and 0.34 +/- 0.3 kgCOD/m(3)/d, respectively, which increased by 34.5% and 20.5%. Independent of GB dose, denitrifying activity was promoted, but anammox activity was drastically deteriorated after excessive GB addition. The optimal GB dose predicated by both Gaussian and Modified-Boltzmann models were 0.42-0.45 mM. Besides, the bacterial activity recovery after excessive GB addition could be analyzed by the Modified-Boltzmann model. With 1.5 mM GB, granular floatation occurred since numerous gas bubbles were inside the granules. In general, exogenous GB addition can mitigate salinity inhibition and promote pollutants removal from saline wastewater. |
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Wos |
000560717900013 |
Publication Date |
2020-07-06 |
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Edition |
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ISSN |
0960-8524 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.4 |
Times cited |
1 |
Open Access |
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Notes |
; This study was financially supported by the National Natural Science Foundation of China (51878362), China Postdoctoral Science Foundation (2017M610410, 2018T110665) and State Key Joint Laboratory of Environment Simulation and Pollution Control (Research Center for Eco-environmental Sciences, Chinese Academy of Sciences) (18K02ESPCR). The authors also thank Dr. Yuan Hou and Dr. Chao Fang from University of Antwerp for numerous discussion. ; |
Approved |
Most recent IF: 11.4; 2020 IF: 5.651 |
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Call Number |
UA @ admin @ c:irua:171118 |
Serial |
6508 |
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Author |
Zhu, W. |
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Title |
Microbial resource management for mainstream partial nitritation/anammox : strategies to enhance the nitrogen conversion efficiency |
Type |
Doctoral thesis |
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Year |
2021 |
Publication |
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Abbreviated Journal |
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Pages |
207 p. |
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Keywords |
Doctoral thesis; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
This thesis provides three potential ways to enhance the nitrogen removal efficiency of mainstream partial nitritation/anammox (PN/A), a key technology to enable energy-positive sewage treatment. In Chapter 1, the typical technologies to promote nitrogen removal efficiency are summarized. In Chapters 2 and 3, the concept ‘winter bioaugmentation with stored summer surplus sludge’ is proposed. Applying that, a cost-effective sludge preservation strategy is required. Preserving PN/A biomass without cooling and redox adjustment proved to be the cost-effective strategy. The reactivation of these stored sludges was also tested in low-temperature systems (15 and 10℃). Respectively 56% and 41% of granules activity compared to pre-storage activity (after Arrhenius-based temperature correction) could be recovered within a month (41% and 32% for flocs activity). In the end, the stored AnAOB bioaugmentation was successfully validated in the lab (20℃). In Chapter 4, a return-sludge nursery concept, applying the sidestream nitritation and blending the resulting effluent with mainstream effluent to achieve an intermediate temperature and nitrogen concentrations, is proposed. That led to a 33 – 36% increase in nitrogen removal efficiency. Arrhenius’ expectations (10 ℃ higher temperature, θ = 1.09) could only explain 49-51% of the activity increase in the nursery reactor, pointing to the role of other factors, e.g., the ~400% elevated electrical conductivity (15-16%), the 56-335% higher effluent nitrogen concentrations (12-14%), and the synergy and unknown factors (20-23%). Thus, the return-sludge biostimulation approach could also enhance nitrogen efficiency in the mainstream. In Chapter 5, the N2O emissions, linked to three typical nitrite-oxidizing bacteria (NOB) suppression strategies (low dissolved oxygen (DO) level, free ammonia (FA), and free nitrous acids (FNA) treatments) were tested in a biofilm system. A low emerged DO level (~0.60 mg O2 L-1) was effective to suppress NOB activity and decrease N2O emissions, but NOB adaptation gradually appeared after 200 days. Further NOB inhibition was successfully achieved by periodical (3 hours per week) FA (~30 mg NH3-N L-1) or FNA (~3 mg HNO2-N L-1) treatments. The FA treatment promoted N2O production, while the FNA treatment had no effect. Thus, PN/A systems should be operated at relatively low DO levels with periodical FNA treatment. In Chapter 6, the major findings proposed and the main conclusions drawn in this thesis are outlined. Beyond that, the possible design of a mainstream PN/A configuration that combined all described three technologies is demonstrated. Overall, the novel insights from this thesis potential to improve nitrogen removal efficiency in the mainstream. |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:184236 |
Serial |
8245 |
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Author |
Zhang, Q.; Vlaeminck, S.E.; DeBarbadillo, C.; Suzuki, R.; Kharkar, S.M.; Al-Omari, A.; Wett, B.; Chandran, K.; Murthy, S.; De Clippeleir, H. |
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Title |
Startup strategies of deammonification reactors treating reject water from thermally hydrolyzed solids |
Type |
P3 Proceeding |
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Year |
2017 |
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Abbreviated Journal |
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Pages |
5 p.
T2 - WEFTEC.17, 30 September 4 October 2017, |
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Keywords |
P3 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Call Number |
UA @ admin @ c:irua:151113 |
Serial |
8579 |
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Author |
Zhang, Q.; Vlaeminck, S.E.; DeBarbadillo, C.; Su, C.; Al-Omari, A.; Wett, B.; Pümpel, T.; Shaw, A.; Chandran, K.; Murthy, S.; De Clippeleir, H. |
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Title |
Supernatant organics from anaerobic digestion after thermal hydrolysis cause direct and/or diffusional activity loss for nitritation and anammox |
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A1 Journal article |
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Year |
2018 |
Publication |
Water research |
Abbreviated Journal |
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143 |
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Pages |
270-281 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Treatment of sewage sludge with a thermal hydrolysis process (THP) followed by anaerobic digestion (AD) enables to boost biogas production and minimize residual sludge volumes. However, the reject water can cause inhibition to aerobic and anoxic ammonium-oxidizing bacteria (AerAOB & AnAOB), the two key microbial groups involved in the deammonification process. Firstly, a detailed investigation elucidated the impact of different organic fractions present in THP-AD return liquor on AerAOB and AnAOB activity. For AnAOB, soluble compounds linked to THP conditions and AD performance caused the main inhibition. Direct inhibition by dissolved organics was also observed for AerAOB, but could be overcome by treating the filtrate with extended aerobic or anaerobic incubation or with activated carbon. AerAOB additionally suffered from particulate and colloidal organics limiting the diffusion of substrates. This was resolved by improving the dewatering process through an optimized flocculant polymer dose and/or addition of coagulant polymer to better capture the large colloidal fraction, especially in case of unstable AD performance. Secondly, a new inhibition model for AerAOB included diffusion-limiting compounds based on the porter-equation, and achieved the best fit with the experimental data, highlighting that AerAOB were highly sensitive to large colloids. Overall, this paper for the first time provides separate identification of organic fractions within THP-AD filtrate causing differential types of inhibition. Moreover, it highlights the combined effect of the performance of THP, AD and dewatering on the downstream autotrophic nitrogen removal kinetics. (C) 2018 Elsevier Ltd. All rights reserved. |
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000443664000027 |
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2018-06-18 |
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0043-1354; 1879-2448 |
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Call Number |
UA @ admin @ c:irua:152911 |
Serial |
8623 |
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Zhang, Q.; Higgins, M.J.; Vlaeminck, S.E.; DeBarbadillo, C.; Suzuki, R.; Kharkar, S.M.; Al-Omari, A.; Wett, B.; Chandran, K.; Murthy, S.; De Clippeleir, H. |
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Minimizing recalcitrant organics and maximizing nitrogen removal linked to advanced biosolids processing at Blue Plains WWTP |
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P3 Proceeding |
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2017 |
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12 p.
T2 - IWA 2017 Conference on Sustainable Wast |
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P3 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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no |
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Call Number |
UA @ admin @ c:irua:151107 |
Serial |
8252 |
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Author |
Zhang, Q.; De Clippeleir, H.; Su, C.; Al-Omari, A.; Wett, B.; Vlaeminck, S.E.; Murthy, S. |
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Title |
Deammonification for digester supernatant pretreated with thermal hydrolysis : overcoming inhibition through process optimization |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Applied microbiology and biotechnology |
Abbreviated Journal |
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Volume |
100 |
Issue |
12 |
Pages |
5595-5606 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
The thermal hydrolysis process (THP) has been proven to be an excellent pretreatment step for an anaerobic digester (AD), increasing biogas yield and decreasing sludge disposal. The goal of this work was to optimize deammonification for efficient nitrogen removal despite the inhibition effects caused by the organics present in the THP-AD sludge filtrate (digestate). Two sequencing batch reactors were studied treating conventional digestate and THP-AD digestate, respectively. Improved process control based on higher dissolved oxygen set-point (1 mg O-2/L) and longer aeration times could achieve successful treatment of THP-AD digestate. This increased set-point could overcome the inhibition effect on aerobic ammonium-oxidizing bacteria (AerAOB), potentially caused by particulate and colloidal organics. Moreover, based on the mass balance, anoxic ammonium-oxidizing bacteria (AnAOB) contribution to the total nitrogen removal decreased from 97 +/- A 1 % for conventional to 72 +/- A 5 % for THP-AD digestate treatment, but remained stable by selective AnAOB retention using a vibrating screen. Overall, similar total nitrogen removal rates of 520 +/- A 28 mg N/L/day at a loading rate of 600 mg N/L/day were achieved in the THP-AD reactor compared to the conventional digestate treatment operating at low dissolved oxygen (DO) (0.38 +/- A 0.10 mg O-2/L). |
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000376456700033 |
Publication Date |
2016-02-19 |
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0175-7598; 1432-0614 |
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UA library record; WoS full record; WoS citing articles |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:134166 |
Serial |
7755 |
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| Permanent link to this record |
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Author |
Zhang, Q.; De Clippeleir, H.; Shaw, A.; DeBarbadillo, C.; Su, C.; Al-Omari, A.; Wett, B.; Chandran, K.; Vlaeminck, S.E.; Murthy, S. |
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| |
Title |
Mechanistic understanding of microbial activity inhibition : case study on sidestream deammonification for digester supernatant pretreated by thermal hydrolysis |
Type |
P3 Proceeding |
| |
Year |
2016 |
Publication |
|
Abbreviated Journal |
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| |
Volume |
|
Issue |
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Pages |
5 p.
T2 - WEF/IWA Nutrient Removal and Recovery Co |
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Keywords |
P3 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:151133 |
Serial |
8214 |
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| Permanent link to this record |
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Author |
Zhang, Q.; De Clippeleir, H.; DeBarbadillo, C.; Su, C.; Al-Omari, A.; Wett, B.; Chandran, K.; Vlaeminck, S.E.; Murthy, S. |
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| |
Title |
Inhibition mechanisms affecting deammonification of dewatering filtrate from thermally hydrolyzed digested solid |
Type |
P3 Proceeding |
| |
Year |
2016 |
Publication |
|
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
9 p.
T2 - WEFTEC.16, 24 - 28 September 2016, New O |
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Keywords |
P3 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Series Editor |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:151123 |
Serial |
8102 |
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| Permanent link to this record |
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Author |
Zhang, Q.; De Clippeleir, H.; Al-Omari, A.; Wett, B.; Vlaeminck, S.E.; Murthy, S. |
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| |
Title |
Sidestream deammonification on thermal hydrolysis process digestate : strategies to overcome nitritation inhibition |
Type |
P3 Proceeding |
| |
Year |
2015 |
Publication |
|
Abbreviated Journal |
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| |
Volume |
|
Issue |
|
Pages |
11 p.
T2 - IWA Nutrient Removal and Recovery 2015: |
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Keywords |
P3 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:151147 |
Serial |
8522 |
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| Permanent link to this record |
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Author |
Zhang, L.; Quinn, B.K.; Hui, C.; Lian, M.; Gielis, J.; Gao, J.; Shi, P. |
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Title |
New indices to balance α-diversity against tree size inequality |
Type |
A1 Journal article |
| |
Year |
2024 |
Publication |
Journal of forestry research |
Abbreviated Journal |
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| |
Volume |
35 |
Issue |
1 |
Pages |
31-39 |
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| |
Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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| |
Abstract |
The number and composition of species in a community can be quantified with alpha-diversity indices, including species richness (R), Simpson's index (D), and the Shannon-Wiener index (HGREEK TONOS). In forest communities, there are large variations in tree size among species and individuals of the same species, which result in differences in ecological processes and ecosystem functions. However, tree size inequality (TSI) has been largely neglected in studies using the available diversity indices. The TSI in the diameter at breast height (DBH) data for each of 999 20 m x 20 m forest census quadrats was quantified using the Gini index (GI), a measure of the inequality of size distribution. The generalized performance equation was used to describe the rotated and right-shifted Lorenz curve of the cumulative proportion of DBH and the cumulative proportion of number of trees per quadrat. We also examined the relationships of alpha-diversity indices with the GI using correlation tests. The generalized performance equation effectively described the rotated and right-shifted Lorenz curve of DBH distributions, with most root-mean-square errors (990 out of 999 quadrats) being < 0.0030. There were significant positive correlations between each of three alpha-diversity indices (i.e., R, D, and H') and the GI. Nevertheless, the total abundance of trees in each quadrat did not significantly influence the GI. This means that the TSI increased with increasing species diversity. Thus, two new indices are proposed that can balance alpha-diversity against the extent of TSI in the community: (1 – GI) x D, and (1 – GI) x H'. These new indices were significantly correlated with the original D and HGREEK TONOS, and did not increase the extent of variation within each group of indices. This study presents a useful tool for quantifying both species diversity and the variation in tree sizes in forest communities, especially in the face of cumulative species loss under global climate change. |
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Wos |
001131698000001 |
Publication Date |
2023-12-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1007-662x; 1993-0607 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
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Open Access |
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Notes |
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Approved |
no |
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| |
Call Number |
UA @ admin @ c:irua:201972 |
Serial |
9061 |
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| Permanent link to this record |
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Author |
Zhang, K.; Wang, J.; Ninakanti, R.; Verbruggen, S.W. |
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Title |
Solvothermal synthesis of mesoporous TiO2 with tunable surface area, crystal size and surface hydroxylation for efficient photocatalytic acetaldehyde degradation |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
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| |
Volume |
474 |
Issue |
|
Pages |
145188-14 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Photocatalytic acetaldehyde degradation exhibits satisfactory performance only at relatively low acetaldehyde flow rates, predominately below 10 × 10-3 mL/min, leaving ample room for improvement. Therefore, it is necessary to prepare more efficient photocatalysts for acetaldehyde degradation. Moreover, the impact of the interaction strength between the titania surface and surface water on the photocatalytic acetaldehyde efficiency is poorly understood. To address these issues, in this work a series of (0 0 1)-faceted anatase titania samples with various surface properties and structures were synthesized via a solvothermal method and tested at high acetaldehyde flow rates under UV light irradiation. With increasing solvothermal time, the pore volume, surface area, and the abundance of surface OH groups all increased, while the crystallite size decreased. These were all identified to be beneficial to promote the degradation performance. When the solvothermal temperature was 180 ℃ and the reaction time was 5 h, the prepared sample displayed the most efficient performance at 19.25× 10-3 mL/min of acetaldehyde (conversion of (74 ± 1)% versus (29 ± 1)% for P25), and achieved a 100 % conversion at 16 × 10-3 mL/min. A weaker interaction strength between surface water and the titania surface was found to improve the acetaldehyde adsorption capacity, thereby promoting the acetaldehyde degradation efficiency. The stability of the best performing sample was tested over 48 h, demonstrating a highly stable performance with no signs of deactivation. Even at a relative humidity of 30 %, the acetaldehyde conversion retains 82% of its efficiency in a dry atmosphere, highlighting its potential in practical applications. |
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Place of Publication |
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Wos |
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Publication Date |
2023-08-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1385-8947; 1873-3212 |
ISBN |
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Additional Links |
UA library record |
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Impact Factor |
15.1 |
Times cited |
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Open Access |
Not_Open_Access: Available from 06.02.2024 |
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Notes |
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Approved |
Most recent IF: 15.1; 2023 IF: 6.216 |
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| |
Call Number |
UA @ admin @ c:irua:198652 |
Serial |
8933 |
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| Permanent link to this record |
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Author |
Zhang, K. |
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| |
Title |
Revealing the correlation between titania support properties and propylphosphonic acid modification by in-depth characterization |
Type |
Doctoral thesis |
| |
Year |
2023 |
Publication |
|
Abbreviated Journal |
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Volume |
|
Issue |
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Pages |
XVI, 262 p. |
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Keywords |
Doctoral thesis; Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Grafting organophosphonic acids modification (PAs) on metal oxides has shown to be a flexible technology to tune the surface properties of metal oxides for various applications. Nevertheless, there are still puzzles that need to be addressed, such as the correlations between metal oxides properties (types of surface reactive sites) and the modification (modification degree), the correlations between metal oxides properties and the properties of modified surfaces. Moreover, the currently used liquid-phase method for the grafting has associated impeding effects of solvent on tailoring the modification degrees, and also causes the formation of metal phosphonate side products. The solid-phase method can induce the unwanted changes in crystal phase of supports. Based on these questions, the three titania supports with divergent surface properties were selected as the metal oxides supports investigated, propylphosphonic acid (3PA) modification was carried out under the same synthesis conditions: four different concentrations, two solvents (water or toluene), and one reaction time (4 h) and temperature (90 ). MeOH chemisorption was introduced to probe the surface (un)reactive sites for 3PA modification. On the other hand, MeOH chemisorption and inverse gas chromatography (IGC) were combined to characterize the changes in surface polarity and acidic properties induced by the modification. Next, a solid-phase method, manual grinding, was proposed to graft 3PA on titania, avoiding the impeding effects of solvent on improving modification degree and the formation of the titania phosphonate side products, as well as preserving the crystal phase. The results indicate that methanol chemisorption can qualitatively analyze the surface active sites that are consumed by 3PA modification, its chemisorption capacity shows the consistent trend with the maximum modification degree, hereby revealing the kinds of interactions that are important in controlling surface coverage. Titania supports is found to play an important role in changes in surface polarity and acidic properties by charactering the three modified titania samples at a similar modification degree using the methanol chemisorption coupled with in-situ infrared and thermogravimetric-mass spectrometer, and the IGC. Moreover, IGC provides additional information about the changes in binding modes. Furthermore, grafting 3PA modification on titania was achieved by manual grinding. Compared to the liquid-phase method, the maximum modification degree obtained by the manual grinding is 25 % higher while using 83.3 % or 75.0% lower amounts of expensive 3PA and limiting the formation of titania phosphonate side products. Compared to the reactive milling method, the proposed manual grinding method preserves the crystal phase(s) of titania. |
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Wos |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:198726 |
Serial |
8924 |
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| Permanent link to this record |
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Author |
Zewdie, M.C.; Van Passel, S.; Moretti, M.; Annys, S.; Tenessa, D.B.; Ayele, Z.A.; Tsegaye, E.A.; Cools, J.; Minale, A.S.; Nyssen, J. |
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Title |
Pathways how irrigation water affects crop revenue of smallholder farmers in northwest Ethiopia: A mixed approach |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Agricultural Water Management |
Abbreviated Journal |
Agr Water Manage |
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Volume |
233 |
Issue |
|
Pages |
106101 |
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Keywords |
A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
The relationship between irrigation water availability and crop revenue is multifaceted. However, most of the previous studies focused only on the direct effect of irrigation water on crop revenue or considered that the indirect effect passes only through the farmers’ improved farm inputs usage. Nevertheless, unlike previous studies, this study argues that a one-sided argument that irrigation water directly causes high crop revenue or indirectly affects crop revenue only via the farmers’ improved farm inputs usage is incomplete, as irrigation water not only directly contributes to crop revenue but also indirectly conduces to crop revenue via both the type of crops produced and the farmers’ improved farm inputs usage. Considering the previous studies’ limitations, this study investigates pathways how small-scale irrigation water affects crop revenue and identifies challenges of small-scale irrigation farming in Fogera district, Ethiopia. Results endorsed that irrigation water has both direct and indirect effects on crop revenue. The indirect effect is 67 percent of the total effect and it is mediated by both the type of crops produced and farmers’ improved farm inputs usage. The result also indicated that irrigation user farmers have a higher income, more livestock assets and resources and better food, housing, and cloths than the non-users. Moreover, challenges related to agricultural output and input market were identified as the most severe problem followed by crop disease. The findings of our study suggest that to utilize the benefits of irrigation water properly, it is crucial to encourage farmers to use more improved farm inputs and to shift from staple to cash crop production. Moreover, farmers are frequently exposed to cheating by illegal brokers in the output market, therefore it is also important to increase farmers’ accessibility to output and input markets, the quality of improved farm inputs, and the bargaining power of farmers with market information. |
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Language |
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Wos |
000525291200025 |
Publication Date |
2020-02-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0378-3774 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.7 |
Times cited |
|
Open Access |
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Notes |
Bahir Dar University – Institutional University Cooperation; |
Approved |
Most recent IF: 6.7; 2020 IF: 2.848 |
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Call Number |
ENM @ enm @c:irua:167592 |
Serial |
6353 |
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| Permanent link to this record |
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Author |
Zankowski, S.P.; Van Hoecke, L.; Mattelaer, F.; de Raedt, M.; Richard, O.; Detavernier, C.; Vereecken, P.M. |
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Title |
Redox layer deposition of thin films of MnO2 on nanostructured substrates from aqueous solutions |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Chemistry of materials |
Abbreviated Journal |
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Volume |
31 |
Issue |
13 |
Pages |
4805-4816 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
In this work, we report a new method for depositing thin films of MnO2 on planar and complex nanostructured surfaces, with high precision and conformality. The method is based on repeating cycles of adsorption of an unsaturated alcohol on a surface, followed by its oxidation with aqueous KMnO4 and formation of thin, solid MnO2. The amount of manganese oxide formed in each cycle is limited by the quantity of the adsorbed alcohol; thus, the growth exhibits the self-limiting characteristics of atomic layer deposition (ALD). Contrary to the typical ALD, however, the new redox layer deposition is performed in air, at room temperature, using common chemicals and simple laboratory glassware, which greatly reduces its cost and complexity. We also demonstrate application of the method for the fabrication of a nanostructured MnO2/Ni electrode, which was not possible with thermal ALD because of the rapid decomposition of the gaseous precursor on the high surface-area substrate. Thanks to its simplicity, the conformal deposition of MnO2 can be easily upscaled and thus exploited for its numerous (electro)chemical applications. |
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Corporate Author |
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Place of Publication |
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Wos |
000475408400021 |
Publication Date |
2019-06-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756; 1520-5002 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:161225 |
Serial |
8465 |
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| Permanent link to this record |
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Author |
Ysebaert, T.; Samson, R.; Denys, S. |
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Title |
Parameterisation of the drag effect of climbers depending on wind speed and LAD |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Sustainable Cities and Society |
Abbreviated Journal |
Sustain Cities Soc |
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Volume |
84 |
Issue |
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Pages |
103979-12 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
The implementation of green walls is increasingly seen as a strategy to tackle urban air pollution and to make cities more climate resilient. The correct description of the vegetation-wind interaction is key in describing the effect of vegetation in computational fluid dynamics (CFD) models. The accuracy of the modelled wind flow is highly linked to the uncertainty about the drag coefficient (C-d). In addition, at low wind speeds viscous drag (K) is not negligible and it should be regarded in CFD models. This research aims to address the uncertainty related to C-d and K by including the effect of climbers on both the momentum and turbulence equations in the Wilcox revised k-omega model. The change of K with increasing Reynolds number showed an increase from 5.10(-8 )m(2) up to the dynamic viscosity of air (asymptotic to 10(-5) m(2)) following a logistic function. Beyond the transition region from viscous to form drag, C-d, in the range of 0.1-1.1, declined with increasing Reynolds number following a power law function. Furthermore, the plant morphological parameters determining permeability and drag coefficient were identified. This study showed that the knowledge of viscous and shape resistance is necessary to obtain accurate statistics for air flow through vegetation. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000831685500001 |
Publication Date |
2022-06-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2210-6707 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.7 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
|
Approved |
Most recent IF: 11.7 |
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| |
Call Number |
UA @ admin @ c:irua:189465 |
Serial |
7187 |
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| Permanent link to this record |
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Author |
Ysebaert, T.; Samson, R.; Denys, S. |
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Title |
Revisiting dry deposition modelling of particulate matter on vegetation at the microscale |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Air quality, atmosphere & health |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Dry deposition is an important process determining pollutant concentrations, especially when studying the influence of urban green infrastructure on particulate matter (PM) levels in cities. Computational fluid dynamics (CFD) models of PM capture by vegetation are useful tools to increase their applicability. The meso-scale models of Zhang et al. (Atmos Environ 35:549-560, 2001) and Petroff and Zhang (Geosci Model Dev 3(2):753-769, 2010) have often been adopted in CFD models, however a comparison of these models with measurements including all PM particle sizes detrimental to health has been rarely reported and certainly not for green wall species. This study presents dry deposition experiments on real grown Hedera helix in a wind tunnel setup with wind speeds from 1 to 4 m s(-1) and PM consisting of a mixture of soot (0.02 – 0.2 mu mu m) and dust particles (0.3 – 10 mu mu m). Significant factors determining the collection efficiency (%) were particle diameter and wind speed, but relative air humidity and the type of PM (soot or dust) did not have a significant influence. Zhang's model outperformed Petroff's model for particles < 0.3 mu mu m, however the inclusion of turbulent impaction in Petroff's model resulted in better agreement with the measurements for particles > 2 – 3 mu mu m. The optimised model had an overall root-mean-square-error of similar to 4% for collection efficiency (CE) and 0.4 cm s-1 for deposition velocity (nu d), which was shown to be highly competitive against previously described models. It can thus be used to model PM deposition on other plant species, provided the correct parameterisation of the drag by this species. A detailed description of the spatial distribution of the vegetation could solve the underestimation for particle sizes of 0.3 – 2 mu mu m. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001125841300001 |
Publication Date |
2023-12-14 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
1873-9318; 1873-9326 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:201986 |
Serial |
9086 |
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| Permanent link to this record |
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Author |
Ysebaert, T.; Koch, K.; Samson, R.; Denys, S. |
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Title |
Green walls for mitigating urban particulate matter pollution : a review |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Urban Forestry & Urban Greening |
Abbreviated Journal |
Urban For Urban Gree |
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Volume |
59 |
Issue |
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Pages |
127014 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Art; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Air pollution caused by particulate matter (PM) is a well-known health issue in urban environments. Urban green infrastructure offers opportunities as a nature-based solution to urban PM pollution. Green walls have advantages over other types of urban green infrastructure, since they can be applied to the enormous available wall area in cities and since they do not interfere with the prevailing ventilation resulting in elevated PM levels. However, this has raised questions about the effectiveness of GW in removing PM and this could explain the limited applicability of green walls to tackle PM pollution. Nevertheless, it is suggested that green walls have a significant unexploited potential and this review article aims to address current knowledge gaps and to propose future research requirements for the implementation of green walls to mitigate urban PM pollution. An in-depth analysis is given of the mechanisms behind PM deposition and the influence of vegetation properties on this process, as well as the practices followed to model PM dispersion and deposition. It was suggested that particle deposition on green walls depends on the green wall species, pollution level, and the residence time of PM in a street (canyon). Rainfall plays an important role in the PM pathway, although it is not a necessary requirement to sustain PM deposition on plant leaves. There are still some discrepancies in the literature about the ideal plant characteristics for PM deposition in terms of the macro- and microstructures that require further investigation, especially in comparison with tree and shrub species. In addition, extensively validated models are required to accurately calculate the impact of green walls on air flow and the PM concentration on site. |
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Wos |
000632597600001 |
Publication Date |
2021-02-06 |
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Series Volume |
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Edition |
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ISSN |
1618-8667 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.113 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 2.113 |
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Call Number |
UA @ admin @ c:irua:175581 |
Serial |
8011 |
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Author |
Ysebaert, T. |
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Title |
Modelling and experimental validation of deposition on vegetation to facilitate urban particulate matter mitigation |
Type |
Doctoral thesis |
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Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
xxvi, 234 p. |
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Keywords |
Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Exposure to air pollution, such as particulate matter (PM), causes adverse health effects, particularly to the respiratory tract and cardiovascular system. PM is the collective name for all kinds of particles ranging from small particles and liquid droplets, which contain organic compounds, acids and metals, to soil or dust particles. One distinguishes PM10, PM2.5 and PM0.1, which have aerodynamic particle sizes smaller than 10, 2.5 and 0.1 µm, respectively. It is mainly the latter that is the most harmful, as PM0.1 penetrates deep into the respiratory system and carries relatively more toxic substances than the other PM fractions. Over a 15-year period, PM concentrations in European member states have fallen by about 30%. Nevertheless, the World Health Organisation (WHO) air quality guidelines, which became stricter in 2021, are exceeded in most places around the world. Particularly in cities, excessive levels of PM are measured and it is here that PM mitigation should be investigated. For this, the implementation of urban green infrastructure, including trees, shrubs, green roofs and green walls, is being looked at. Plants hinder airflow and remove PM from the air by deposition on their leaves and branches. This process is known as dry deposition. Plants can capture PM very efficiently, due to their complex structure of leaves and branches. Green walls offer significant advantages over other types of urban green infrastructure because they can grow on the huge available wall area and, because they do not hinder air circulation, as we sometimes see with trees. Green walls are believed to have a much greater, untapped potential to reduce PM pollution. However, a literature review showed that we do not know the quantitative impact of green walls and lack the tools and/or general methodology to do so. The objective of this thesis is therefore to develop a method for assessing PM removal by green walls, based on predictive models and based on relevant parameters that are experimentally determined. Computational fluid dynamics (CFD) is a numerical method to simulate airflow in complex environments such as cities. These models can also simulate the vegetation-wind interaction in detail and are interesting tools to assess the effect of green walls on PM concentrations in real environments. It is important to first study the aerodynamic effect of green walls and parameterise it correctly in CFD models. Plants decrease the wind speed and create turbulence through a combination of viscous and form drag, which are determined by the permeability (K) and drag coefficient (Cd), respectively. Wind tunnel experiments were conducted with three commonly found climbers (Hedera helix, Parthenocissus tricuspidata and Parthenocissus quinquefolia) and the variation of leaf area density was investigated for two of them. It was observed that the air resistance depended on plant species, leaf area density and wind speed. The difference between the plant species was assigned to the functional leaf size (FLS), the ratio of the largest circle within the boundaries of the leaf to the total leaf area. FLS is likely associated with other morphological characteristics of plants that, when considered collectively, provide a more comprehensive representation of leaf complexity. The pressure and velocity measurements obtained were used to optimise the permeability and drag coefficient in a CFD model. At wind speeds below 0.6 m s-1, the resistance was mainly determined by viscous drag and a larger leaf size resulted in a higher viscous drag. At wind speeds above 1.5 m s-1, form drag was dominant and the parameterised Cd decreased with increasing wind speed due to the sheltering effect of successive plant elements. The leaf area density had a significant effect on K and Cd and, is therefore an important plant parameters in CFD models. The main conclusion here is that the common practice of using a constant Cd to model the influence of plants on the air flow leads to deviations from reality. Wind tunnels are highly suitable to study the impact of green walls on PM concentration under controlled environmental conditions. For this purpose, a new wind tunnel setup was built and great attention was paid to obtaining a uniform air flow. Thus, based on CFD models, appropriate flow controllers were chosen, consisting of honeycombs and screens with different mesh sizes. New PM generation devices and measuring equipment were installed and set up appropriately. Devices were available for generating and measuring ultrafine dust (<0.1 µm, i.e. PM0.1) and fine dust (<0.3 µm, i.e. PM0.3) consisting of soot particles, and, on the other hand, fine dust with particle sizes smaller than 2.5 (PM2.5) and 10 µm (PM10) consisting of 'Arizona fine test dust'. With the new wind tunnel setup, it was possible to measure the influence of Hedera helix (common ivy), grown in a planter against a climbing aid, on the PM concentration and this was expressed by a collection efficiency, i.e. the difference in concentration in front and behind the plants normalised for the incoming concentration. The collection efficiency of H. helix depended on the particle size of the PM and wind speed. The collection efficiency decreased when the particle size increased from 0.02 to 0.2 µm and increased again for particle sizes above 0.3 µm. The collection efficiency also increased with increasing wind speed, especially for particle sizes > 0.03 µm. On the other hand, relative humidity and the type of PM (soot or dust) did not significantly affect the collection efficiency. The main objective of this study was to obtain an optimised size-resolved deposition model. Dry deposition occurs through several mechanisms, in particular gravity, diffusion, impaction and interception, and the subsequent resuspension of deposited PM back to the environment. The modelling of these mechanisms was described by \citet{Zhang2001} and \citet{Petroff2010}. The data obtained from the wind tunnel experiments allowed validating these deposition models. It was for the first time that deposition of real PM on green walls was studied. The different PM deposition mechanisms were found to be strongly dependent on particle size and wind speed. The models of \citet{Zhang2001} and \citet{Petroff2010} each matched PM concentration measurements for only certain particle sizes. Therefore, a combination of the two models was investigated and the root mean square error was lower by on average 3.5% (PM < 0.03 µm) and 46% (PM > 0.03 µm) compared to the original models at wind speeds greater than 1.5 m s-1. For wind speeds less than 1.5 m s-1, the optimised model did not differ from the original models. The optimised model was able to meet the imposed criteria for air quality models, where a correct model exhibits low deviation from measurements ('normalised mean square error' < 1.5), low bias ('fractional bias' between -0.3 and 0.3) and high R2. In comparison, the R$2$ of the optimised model was 0.57, while that of Zhang et al. (2001) and Petroff et al. (2010) was 0.23 and 0.31, respectively. The optimised model was however characterised by a high scatter, with the fraction of modeled results located within a factor of two of the measurements being lower than 50. A model study with a green façade oriented parallel to the incoming airflow showed that deposition by interception and impaction reduced remarkably, but that the orientation had no effect on deposition by Brownian diffusion. A promising green wall form for PM mitigation is the living wall system (LWS). LWS consist of supporting structures with substrate to grow plants in and can be planted with a variety of plant species. This allows to select plant species with optimal characteristics to achieve PM deposition. These characteristics refer to the macro- and microstructure of the leaves, and research has been conducted mainly on these. On the other hand, the influence of the supporting structure and substrate on PM concentrations has rarely been studied. With the new wind tunnel setup, LWS from different manufacturers were tested for their ability to capture PM. The setups were subjected for three hours to an air flow with a low PM concentration (resuspension phase) and then for three hours to an air flow to which additional PM was added (deposition phase). Some setups were able to decrease the PM concentration during both phases, while others just caused the concentration to increase. Some systems were able to reduce particulate matter concentration during both phases, namely LWS consisting of planters (-2% and -4% for PM0.1 and PM2.5, respectively) and textile cloths (-23% and -5% for PM0.1 and PM2.5, respectively). While other systems actually resulted in an increase in concentration especially LWS existing textile fabrics consisting of geotextiles (+11% for both PM fractions) and with moss as substrate (+2% and +5% for PM0.1 and PM2.5, respectively). This highlights the importance of careful selection of suspension systems to reduce particulate matter concentrations. Further research is therefore needed on the materials used in these systems in relation to their particulate content, as well as on plant development in these systems. In addition to air measurements, measurements were taken of the amount of PM deposited on the leaves and suspension system of LWS. This allowed the difference in PM resuspension and deposition between plant species to be investigated. The amount of deposited particulate matter was determined based on 'saturation isothermal remanent magnetisation' (SIRM), a measure of magnetisable particulate matter. This was possible because the added 'Arizona fine test dust' contained iron oxide. However, no significant difference was observed between the SIRM values measured before the wind tunnel experiment, after resuspension and after deposition. This suggested that the iron oxide content in the Arizona fine test dust was too low to measure a significant difference in the SIRM values on leaves after three hours. The plant species did give rise to different SIRM values ranging between 5 and 260 µ A. In particular, SIRM values above 26 µ A were observed for the plant species that were grouped due to their significantly higher accumulation of PM. 'Specific leaf area' (SLA), specifically the ratio of the one-sided 'fresh' leaf area to its dry mass, was the significant leaf characteristic. SLA correlated with leaf complexity. In particular, plant species with elongated leaves were characterized by low SLA, high FLS and high complexity and showed significantly higher SIRM values. Finally, the optimised size-resolved deposition model was also tested in an urban model to get an idea of the impact of a green wall on PM concentrations in a so-called 'street canyon'. These are narrow streets with high buildings on both sides, making air pollution more persistent. To this end, an ideal scenario was tested in which a green wall was introduced along both sides of the street over a length of about 270 m. The model result showed a decrease in PM2.5 and PM10 of 46 ± 12% and 52 ± 14%. This result is of course for a very optimal scenario where the green wall covers the entire building façades. Since this is not feasible in reality, other ways of promoting contact between green walls and polluted air can be explored. The insights obtained illustrate that the use of climbing plants can be a cost-effective and environmentally friendly solution to reduce PM concentrations. Moreover, the findings showed that models can be used to investigate the impact of green walls on PM levels. These findings fit within the broader context of designing healthy and sustainable urban environments and developing innovative solutions based on solid scientific knowledge. |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:199439 |
Serial |
8900 |
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Author |
Ying, J.; Lenaerts, S.; Symes, M.D.; Yang, X.-Y. |
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Title |
Hierarchical design in nanoporous metals |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Advanced Science |
Abbreviated Journal |
Adv Sci |
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Volume |
9 |
Issue |
27 |
Pages |
2106117-2106120 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Hierarchically porous metals possess intriguing high accessibility of matter molecules and unique continuous metallic frameworks, as well as a high level of exposed active atoms. High rates of diffusion and fast energy transfer have been important and challenging goals of hierarchical design and porosity control with nanostructured metals. This review aims to summarize recent important progress toward the development of hierarchically porous metals, with special emphasis on synthetic strategies, hierarchical design in structure-function and corresponding applications. The current challenges and future prospects in this field are also discussed. |
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Wos |
000831201000001 |
Publication Date |
2022-07-28 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2198-3844 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
15.1 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 15.1 |
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Call Number |
UA @ admin @ c:irua:189646 |
Serial |
7170 |
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Author |
Yildiz, A.; Chouki, T.; Atli, A.; Harb, M.; Verbruggen, S.W.; Ninakanti, R.; Emin, S. |
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Title |
Efficient iron phosphide catalyst as a counter electrode in dye-sensitized solar cells |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
ACS applied energy materials |
Abbreviated Journal |
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Volume |
4 |
Issue |
10 |
Pages |
10618-10626 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Developing an efficient material as a counter electrode (CE) with excellent catalytic activity, intrinsic stability, and low cost is essential for the commercial application of dye-sensitized solar cells (DSSCs). Transition metal phosphides have been demonstrated as outstanding multifunctional catalysts in a broad range of energy conversion technologies. Here, we exploited different phases of iron phosphide as CEs in DSSCs with an I–/I3–-based electrolyte. Solvothermal synthesis using a triphenylphosphine precursor as a phosphorus source allows to grow a Fe2P phase at 300 °C and a FeP phase at 350 °C. The obtained iron phosphide catalysts were coated on fluorine-doped tin oxide substrates and heat-treated at 450 °C under an inert gas atmosphere. The solar-to-current conversion efficiency of the solar cells assembled with the Fe2P material reached 3.96 ± 0.06%, which is comparable to the device assembled with a platinum (Pt) CE. DFT calculations support the experimental observations and explain the fundamental origin behind the improved performance of Fe2P compared to FeP. These results indicate that the Fe2P catalyst exhibits excellent performance along with desired stability to be deployed as an efficient Pt-free alternative in DSSCs. |
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Wos |
000711236300022 |
Publication Date |
2021-10-08 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2574-0962 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:181953 |
Serial |
7853 |
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Author |
Yao, W.; Niinemets, Ü.; Yao, W.; Gielis, J.; Schrader, J.; Yu, K.; Shi, P. |
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Title |
Comparison of two simplified versions of the Gielis equation for describing the shape of bamboo leaves |
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A1 Journal article |
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Year |
2022 |
Publication |
Plants |
Abbreviated Journal |
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Volume |
11 |
Issue |
22 |
Pages |
3058-11 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Bamboo is an important component in subtropical and tropical forest communities. The plant has characteristic long lanceolate leaves with parallel venation. Prior studies have shown that the leaf shapes of this plant group can be well described by a simplified version (referred to as SGE-1) of the Gielis equation, a polar coordinate equation extended from the superellipse equation. SGE-1 with only two model parameters is less complex than the original Gielis equation with six parameters. Previous studies have seldom tested whether other simplified versions of the Gielis equation are superior to SGE-1 in fitting empirical leaf shape data. In the present study, we compared a three-parameter Gielis equation (referred to as SGE-2) with the two-parameter SGE-1 using the leaf boundary coordinate data of six bamboo species within the same genus that have representative long lanceolate leaves, with >300 leaves for each species. We sampled 2000 data points at approximately equidistant locations on the boundary of each leaf, and estimated the parameters for the two models. The root–mean–square error (RMSE) between the observed and predicted radii from the polar point to data points on the boundary of each leaf was used as a measure of the model goodness of fit, and the mean percent error between the RMSEs from fitting SGE-1 and SGE-2 was used to examine whether the introduction of an additional parameter in SGE-1 remarkably improves the model’s fitting. We found that the RMSE value of SGE-2 was always smaller than that of SGE-1. The mean percent errors among the two models ranged from 7.5% to 20% across the six species. These results indicate that SGE-2 is superior to SGE-1 and should be used in fitting leaf shapes. We argue that the results of the current study can be potentially extended to other lanceolate leaf shapes. |
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Wos |
000887783400001 |
Publication Date |
2022-11-14 |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
2223-7747 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:191859 |
Serial |
7289 |
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Author |
Yang, Z.; Zhu, W.; Yu, D.; Bo, Y.; Li, J. |
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Title |
Enhanced carbon and nitrogen removal performance of simultaneous anammox and denitrification (SAD) with mannitol addition treating saline wastewater |
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A1 Journal article |
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Year |
2019 |
Publication |
Journal of chemical technology and biotechnology |
Abbreviated Journal |
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Volume |
94 |
Issue |
2 |
Pages |
377-388 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
BACKGROUND Simultaneous anammox and denitrification (SAD) can remove carbon and nitrogen. However, its performance is suppressed under saline surroundings. In this work, mannitol was used to enhance a SAD process treating saline wastewater. RESULTS The optimum carbon and nitrogen removal was achieved at 0.2 mmol L-1 mannitol, during which ammonium removal efficiency (ARE), nitrite removal efficiency (NRE) and chemical oxygen demand (COD) removal efficiency were 96.95%, 93.70% and 90.05%, respectively. The maximum ammonium removal rate (ARR), nitrite removal rate (NRR) and the specific anammox activity (SAA) were increased by 25.49%, 55.84% and 33.83% with optimum addition (0.2 mmol L-1 mannitol) respectively. The diameter of sludge was enlarged with the addition of mannitol (<= 0.2 mmol L-1). The Tseng-Wayman model was more suitable to simulate the whole SAD process. The modified logistic model, the modified Boltzman model and the modified Gompertz model were all appropriate to describe nitrogen removal in a typical cycle with the addition of mannitol. CONCLUSION Mannitol was effective in enhancing a SAD process treating saline wastewater, and maximum nitrogen removal was achieved at mannitol = 0.2 mmol L-1. The Tseng-Wayman model satisfactorily predicted the whole SAD process treating saline wastewater with mannitol addition. (c) 2018 Society of Chemical Industry |
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Wos |
000455262100004 |
Publication Date |
2018-07-26 |
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Edition |
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ISSN |
0268-2575; 1097-4660 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:156712 |
Serial |
7911 |
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Author |
Xie, Y.; Van Tendeloo, M.; Zhu, W.; Peng, L.; Vlaeminck, S.E. |
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Title |
Autotrophic nitrogen polishing of secondary effluents : Alkaline pH and residual nitrate control S0-driven denitratation for downstream anammox treatment |
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A1 Journal article |
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Year |
2023 |
Publication |
Journal of Water Process Engineering |
Abbreviated Journal |
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Volume |
56 |
Issue |
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Pages |
104402-104409 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Energy-lean nitrogen removal technologies, such as partial nitritation/anammox, often encounter effluent issues due to elevated nitrate and ammonium levels. This study proposed a novel autotrophic polishing strategy coupling sulfur-driven denitratation with anammox. To explore the denitratation potential in obtaining stable and sufficient nitrite accumulation, the effects of pH, residual nitrate level, and biomass-specific nitrate loading rate (BSNLR) were investigated in an S0-packed bed reactor at low hydraulic retention time (i.e., 0.2 h). Implementing pH and residual nitrate control strategies would be easier in practice than BSNLR control to polish secondary effluent. Alkaline pH values could realize successful nitrite accumulation without residual nitrate, and further intensify the accumulation under increased residual nitrate levels. The nitrate level was positively correlated with the nitrite accumulation efficiency. At pH 8.5 and nitrate concentration of 1.0 ± 0.8 mg N L−1, sulfur-driven denitratation could successfully maintain nitrite accumulation of 6.4 ± 1.0 mg NO2−-N L−1, ideally for the downstream anammox in case of residual ammonium levels of around 5 mg N L−1. Since Thiobacillus members play a key role in managing nitrite accumulation, their abundance should be guaranteed in the practical application. |
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Wos |
001103341400001 |
Publication Date |
2023-10-18 |
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Edition |
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ISSN |
2214-7144 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
7 |
Times cited |
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Open Access |
Not_Open_Access: Available from 18.04.2024 |
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Notes |
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Approved |
Most recent IF: 7; 2023 IF: NA |
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Call Number |
UA @ admin @ c:irua:200036 |
Serial |
8835 |
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Author |
Xie, Y.; Spiller, M.; Vlaeminck, S.E. |
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A bioreactor and nutrient balancing approach for the conversion of solid organic fertilizers to liquid nitrate-rich fertilizers : mineralization and nitrification performance complemented with economic aspects |
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A1 Journal article |
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Year |
2022 |
Publication |
The science of the total environment |
Abbreviated Journal |
Sci Total Environ |
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Volume |
806 |
Issue |
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Pages |
150415 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Due to the high water- and nutrient-use efficiency, hydroponic cultivation is increasingly vital in progressing to environment-friendly food production. To further alleviate the environmental impacts of synthetic fertilizer production, the use of recovered nutrients should be encouraged in horticulture and agriculture at large. Solid organic fertilizers can largely contribute to this, yet their physical and chemical nature impedes application in hydroponics. This study proposes a bioreactor for mineralization and nitrification followed by a supplementation step for limiting macronutrients to produce nitrate-based solutions from solid fertilizers, here based on a novel microbial fertilizer. Batch tests showed that aerobic conversions at 35 °C could realize a nitrate (NO₃−-N) production efficiency above 90% and a maximum rate of 59 mg N L−1 d−1. In the subsequent bioreactor test, nitrate production efficiencies were lower (44–51%), yet rates were higher (175–212 mg N L−1 d−1). Calcium and magnesium hydroxide were compared to control the bioreactor pH at 6.0 ± 0.2, while also providing macronutrients for plant production. A mass balance estimation to mimic the Hoagland nutrient solution showed that 92.7% of the NO₃−-N in the Ca(OH)₂ scenario could be organically sourced, while this was only 37.4% in the Mg(OH)₂ scenario. Besides, carbon dioxide (CO₂) generated in the bioreactor can be used for greenhouse carbon fertilization to save operational expenditure (OPEX). An estimation of the total OPEX showed that the production of a nutrient solution from solid organic fertilizers can be cost competitive compared to using commercially available liquid inorganic fertilizer solutions. |
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Wos |
000707640400021 |
Publication Date |
2021-09-20 |
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ISSN |
0048-9697 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.8 |
Times cited |
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Open Access |
OpenAccess |
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Approved |
Most recent IF: 9.8 |
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Call Number |
UA @ admin @ c:irua:181787 |
Serial |
7132 |
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Author |
Xie, Y.; Jia, M.; De Wilde, F.; Daeninck, K.; De Clippeleir, H.; Verstraete, W.; Vlaeminck, S.E. |
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Feasibility of packed-bed trickling filters for partial nitritation/anammox : effects of carrier material, bottom ventilation openings, hydraulic loading rate and free ammonia |
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A1 Journal article |
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Year |
2023 |
Publication |
Bioresource technology |
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373 |
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128713-128719 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
This study pioneers the feasibility of cost-effective partial nitritation/anammox (PN/A) in packed-bed trickling filters (TFs). Three parallel TFs tested different carrier materials, the presence or absence of bottom ventilation openings, hydraulic loading rates (HLR, 0.4–2.2 m3 m−2 h−1), and free ammonia (FA) levels on synthetic medium. The inexpensive Argex expanded clay was recommended due to the similar nitrogen removal rates as commercially used plastics. Top-only ventilation at an optimum HLR of 1.8 m3 m−2 h−1 could remove approximately 60% of the total nitrogen load (i.e., 300 mg N L-1 d−1, 30 °C) and achieve relatively low NO3–-N accumulation (13%). Likely FA levels of around 1.3–3.2 mg N L-1 suppressed nitratation. Most of the total nitrogen removal took place in the upper third of the reactor, where anammox activity was highest. Provided further optimizations, the results demonstrated TFs are suitable for low-energy shortcut nitrogen removal. |
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000945892500001 |
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2023-02-07 |
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ISSN |
0960-8524 |
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UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.4 |
Times cited |
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Open Access |
OpenAccess |
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Approved |
Most recent IF: 11.4; 2023 IF: 5.651 |
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Call Number |
UA @ admin @ c:irua:193652 |
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7306 |
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Author |
Xie, Y. |
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Bioreactor strategies for sustainable nitrogen cycling based on mineralization/nitrification, partial nitritation/anammox or sulfur-based denitratation |
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Doctoral thesis |
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2021 |
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iv, 205 p. |
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Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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In the biogeochemical flows on Earth, the reactive nitrogen (Nr) level has three times surpassed the safe boundary. The severe transgression of this boundary goes against sustainable planetary development. The modern food production process excessively relies on synthetic Nr fertilizers from the Haber– Bosch process. However, the massive loss of valuable nitrogen resources (i.e., 78-89%) from agriculture has been causing severe nitrogen cascade. Besides, the domestic wastewater in some local areas is discharged without proper treatment, making it a nonnegligible source of Nr pollution for local water bodies. Anthropogenic activities keep pumping out Nr pollution via point-source and non-point-source (NPS) emissions. Compared to the NPS emissions, point sources give visible and identified waste streams. It is vital to intervene the nitrogen cascade from point sources and facilitate humanity back to the safe Nr boundary. The collected and collectible Nr streams from food production, waste management, and recycling secondary raw materials can be used as waste-based fertilizers for agricultural cultivation. Besides the well-investigated recovery of inorganic Nr, organic Nr accounts for a massive Nr proportion on the Earth. Proper handling and treatment make these useful organic fertilizers for soil-based cultivation. However, these organic Nr fertilizers cannot directly apply to fertigation or hydroponic cultivation systems, and further biological conversion via nitrogen mineralization and nitrification to nitrate is essential. Besides the direct Nr cycling, the indirect Nr cycling ‘over the atmosphere’ should also be considered. In this way, the nitrogen cycle can be completed via converting the waste Nr back to nitrogen gas (i.e., Nr removal) and then synthesizing into Nr again. The municipal wastewater treatment plants receive a vast amount of low-strength Nr wastewater (mainly as ammonium) daily. Compared to the conventional nitrification/denitrification process, partial nitritation/anammox (PN/A) is considered a resource- and cost-effective technology for wastewater with a low COD/N ratio. Moreover, the novel autotrophic denitratation/anammox process could be a good Nr removal process for wastewater containing both ammonium and nitrate. This Ph.D. thesis aimed to develop Nr recovery, conversion, and removal bioreactor strategies for different types of waste streams and biomass. Nr recovery was investigated on high-strength Nr waste streams for fertigation or hydroponic applications in Chapters 2 and 3. On the other hand, Nr removal was studied on the medium- to low-strength Nr waste streams in Chapters 4 and 5. In Chapter 2, a novel mineralization and nitrification system was proposed, producing nutrient solutions from solid organic fertilizers for hydroponic systems. Batch tests showed that aerobic incubation at 35°C could realize the NO₃⁻-N production efficiency above 90% from a novel microbial fertilizer. Subsequently, in the stirred tank bioreactor test, NO₃⁻-N production efficiency stabilized in a range of 44-51% under the influent loading rate of 400 mg TN L⁻¹ d⁻¹ at a 5-day HRT. Using Ca(OH)₂ and Mg(OH)₂ as pH control reagents generated the nutrient solutions with different P, Ca, and Mg nutrient levels. After modeling the nutrient balancing process, the proportion of organic-sourced NO₃⁻-N in the Hoagland nutrient solution (HNS) of Ca(OH)₂ scenario was 92.7%, while only 37.4% in the Mg(OH)₂ scenario. Compared to commercial scenarios, the total costs of the organic-sourced HNS can be cost-competitive for hydroponic cultivation. In Chapter 3, the Nr recovery as nitrate (NO₃⁻-N) from diluted human urine (around 670 mg N L⁻¹) was explored in a trickling filter (TF) for the first time. A novel concept of in-situ integrating the TF system into hydroponic systems was proposed as meaningful progress towards sustainable agriculture. The difference between synthetic and real urine in nitrification efficiency was found to be negligible. The full nitrification of alkalinized real urine was realized in the pH-controlled TF by calcium hydroxide (Ca(OH)₂) at around pH 6. The TF could handle different urine collection batches and maintain relatively stable nitrification performance, with NO₃⁻-N production efficiency and rate of 88±3% and 136±4 mg N L⁻¹ d⁻¹, respectively. The optimal HLR to realize this nitrification performance was 2 m³ m⁻² h⁻¹, with energy consumption of 1.8 kWh electricity kg⁻¹ NO₃⁻-N production. Ca(OH)₂, as a cheap base, its triple advantages on urine alkalinization, full nitrification, and macronutrient supplementation were successfully demonstrated in our proposed concept. In Chapter 4, towards more sustainable wastewater treatment, the feasibility of one-stage partial nitritation/anammox (PN/A) was investigated in three parallel packed-bed trickling filters (TFs), with three types of carrier materials of different specific surface areas. Synthetic wastewater containing 100-250 mg NH₄⁺-N L⁻¹ was tested to mimic medium-strength household waste streams after carbon removal. Interestingly, the cheap carrier based on expanded clay achieved similar rates as commercially used plastic carrier materials. The top passive ventilation combined with an optimum hydraulic loading rate of 1.8 m³ m⁻² h⁻¹ could reach approximately 60% total nitrogen (TN) removal at a rate of 300 mg N L⁻¹ d⁻¹. A relatively low NO₃⁻-N production (13%) via PN/A was achieved in TFs. Most of the TN removal took place in the top compartment, where anammox activity was the highest. Energy consumption estimation (0.78 kWh electricity g⁻¹ N removed) suggested that the proposed process could be a suitable low-cost alternative for nitrogen removal. In Chapter 5, coupling sulfur-driven denitratation (SDN) with anammox was proposed to treat the wastewater containing both NO₃⁻-N and NH₄⁺-N, like the secondary effluents of mainstream PN/A processes. To explore the feasibility of sufficient and stable NO₂⁻-N accumulation via SDN in the long term, the effects of pH setpoints, residual NO₃⁻-N level, and biomass-specific NO₃⁻-N loading rate (BSNLR) were investigated. Alternating the pH setpoints between 7.0 and 8.5 could temporarily stimulate the NO₂⁻-N accumulation. Both the residual NO₃⁻-N and BSNLR showed highly positive correlations with the NO₂⁻-N accumulation efficiency. Under the control of pH 8.5, 1.0±0.8 mg NO₃⁻-N L⁻¹ and 150±42 mg NO₃⁻-N g⁻¹ VSS d⁻¹, SDN could produce 6.4±1.0 mg NO₂⁻-N L⁻¹ in the short term. Thiobacillus members may play a crucial role in managing the NO₂⁻-N accumulation, but the reduction of abundance and possible adaptation significantly impaired the efficacy of control strategies in the long run. Overall, novel technologies have been proposed to sustainably convert Nr in waste streams and biomass. The decision for Nr recovery versus removal and synthesis should be based on specific cases with the best environmental, economic, and human-health sustainability. In the future, the Nr management concepts should be further improved to make the nitrogen cycle more sustainable with higher resource use efficiency and less Nr emissions to the environment. Although the thesis is mainly focused on limited types of Nr waste streams, it pointed out the direction of sustainable Nr management and could facilitate the Nr back to the safe boundary in the long run. |
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Notes |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:182099 |
Serial |
7563 |
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