The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
Manuel Soto - One of the best experts on this subject based on the ideXlab platform.
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Effect of different bypass Rates and unit area ratio in hybrid constructed wetlands
Environmental Science and Pollution Research, 2020Co-Authors: Omar Gael Gonzalo, Isabel Ruiz, Manuel SotoAbstract:This study presents the performance of a hybrid constructed wetland (Bp(VF + HF)_2:1) system which consists of an unsatuRated vertical flow (VF) unit followed by a satuRated down-flow unit simulating horizontal flow (HF) with HF/VF area ratio of 0.5 and influent bypass to the HF unit. Treating synthetic wastewater simulating municipal wastewater, optimum total nitrogen (TN) removal (57%) was reached at 39% bypass and Surface Loading Rate (SLR) of 33 g BOD_5/m^2 day and 9.7 g TN/m^2 day (overall system). On the other hand, treating actual municipal wastewater, the system reached 63% TN removal at 30% bypass and SLR of 18 g BOD_5/m^2 day and 4.7 g TN/m^2 day. Surface removal Rates reached 5.5 and 3.0 g TN/m^2 day for synthetic and municipal wastewater. Surface nitrification Rate in the VF unit was in the range of 5.0–7.4 and 3.6–3.8 g N/m^2 day for synthetic and municipal wastewater, respectively, indicating a large effect of wastewater characteristics on the nitrification process. Infiltration Rate in the VF unit remained high and far from clogging risk. Overall greenhouse gas emissions were 0.11 (N_2O) and 0.41 (CH_4) g/m^2 day which corresponded to emissions factors (relative to total organic carbon and TN influent) of 0.7% (N_2O) and 3.6% (CH_4). Compared with a similar system with a different HF/VF area ratio of 2.0, organic matter and nitrogen removal efficiency was similar, but Surface removal Rates were about 3 times higher.
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Hydrolytic anaerobic reactor and aeRated constructed wetland systems for municipal wastewater treatment - HIGHWET project.
Environmental technology, 2016Co-Authors: A. Pascual, D. De La Varga, Carlos A. Arias, D. Van Oirschot, R. Kilian, J. A. Álvarez, Manuel SotoAbstract:The HIGHWET project combines the hydrolytic up-flow sludge bed (HUSB) anaerobic digester and constructed wetlands (CWs) with forced aeration for decreasing the footprint and improving effluent quality. The HIGHWET plant in A Coruña (NW of Spain) treating municipal wastewater consists of a HUSB and four parallel subSurface horizontal flow (HF) CWs. HF1, HF2 and HF3 units are fitted with forced aeration, while the control HF4 is not aeRated. All the HF units are provided with effluent recirculation, but different heights of gravel bed (0.8 m in HF1 and HF2, and 0.5 m in HF3 and HF4) are implemented. Besides, a tobermorite-enriched material was added in the HF2 unit in order to improve phosphorus removal. The HUSB 76-89% of total suspended solids (TSS) and about 40% of chemical oxygen demand (COD) and biological oxygen demand (BOD). AeRated HF units reached above 96% of TSS, COD and BOD at a Surface Loading Rate of 29-47 g BOD5/m2·d. An aeration regime ranging from 5 h on/3 h off to 3 h on/5 h off was found to be adequate to optimize nitrogen removal, which ranged from 53% to 81%. Average removal Rates of 3.4 ± 0.4 g total nitrogen (TN)/m2·d and 12.8 ± 3.7 g TN/m3·d were found in the aeRated units, being 5.5 and 4.1 times higher than those of the non-aeRated system. The tobermorite-enriched HF2 unit showed a distinct higher phosphate (60-67%) and total phosphorus (54%) removal.
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Effect of plants and Surface Loading Rate on the treatment efficiency of shallow subSurface constructed wetlands
Ecological Engineering, 2016Co-Authors: T. Carballeira, I. Ruiz, Manuel SotoAbstract:Abstract The aim of this research was to study the influence of the presence of plants and of plant species on the treatment efficiency of shallow (0.3 m effective depth) horizontal subSurface flow constructed wetlands (CWs) treating diluted municipal wastewater. The pilot plant was situated in A Coruna (Spain) and constituted of five CW units in parallel: CW1 (unplanted), CW2 ( Juncus effusus ) CW3 ( Iris pseudacorus ), CW4 ( Typha latifolia L.) and CW5 ( Phragmites australis ). A long term study (from October 2009 to March 2012) was carried out with five monitoring campaigns during the two first years of operation at low Surface Loading Rate (SLR, 2.5 g BOD 5 /m 2 d on average) and two monitoring campaigns during the third year at design SLR (4.7 g BOD 5 /m 2 d on average). At low SLR Rate, significant differences between units were not found for TSS (89–93%), COD (83–88%) or BOD 5 (90–95%) percentage removal which, in turn, appeared at design SLR, when BOD 5 removal decreased to 78% (CW1), 69% (CW4), 87% (CW2), 86% (CW3) and 94% (CW5). Thus, the effect of plants on the removal efficiency of organic matter (COD, BOD 5 ) appeared to be dependent on the Loading Rate. CW2 reached the highest nitrogen removal, followed by CW4, CW5 and CW3 at a similar level and, finally, by CW1. Results indicate that the additional nitrogen removal Rate in planted units increased with plant biomass productivity which also determined evapotranspiration variability between units. Typha latifolia L. appeared to be the most sensitive species to adverse conditions.
Miklas Scholz - One of the best experts on this subject based on the ideXlab platform.
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Wetlands for wastewater treatment and subsequent recycling of treated effluent: a review
Environmental Science and Pollution Research, 2018Co-Authors: Suhad A. Almuktar, Suhail N. Abed, Miklas ScholzAbstract:Due to water scarcity challenges around the world, it is essential to think about non-conventional water resources to address the increased demand in clean freshwater. Environmental and public health problems may result from insufficient provision of sanitation and wastewater disposal facilities. Because of this, wastewater treatment and recycling methods will be vital to provide sufficient freshwater in the coming decades, since water resources are limited and more than 70% of water are consumed for irrigation purposes. Therefore, the application of treated wastewater for agricultural irrigation has much potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for plant production. Among the current treatment technologies applied in urban wastewater reuse for irrigation, wetlands were concluded to be the one of the most suitable ones in terms of pollutant removal and have advantages due to both low maintenance costs and required energy. Wetland behavior and efficiency concerning wastewater treatment is mainly linked to macrophyte composition, substRate, hydrology, Surface Loading Rate, influent feeding mode, microorganism availability, and temperature. Constructed wetlands are very effective in removing organics and suspended solids, whereas the removal of nitrogen is relatively low, but could be improved by using a combination of various types of constructed wetlands meeting the irrigation reuse standards. The removal of phosphorus is usually low, unless special media with high sorption capacity are used. Pathogen removal from wetland effluent to meet irrigation reuse standards is a challenge unless supplementary lagoons or hybrid wetland systems are used.
Shoupeng Duan - One of the best experts on this subject based on the ideXlab platform.
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Optimizing the inclined plate settler for a high-Rate microaerobic activated sludge process for domestic wastewater treatment: A theoretical model and experimental validation
International Biodeterioration & Biodegradation, 2020Co-Authors: Hangyu Zhang, Shaokui Zheng, Xueyu Zhang, Shoupeng DuanAbstract:Abstract This study used a theoretical model and an experimental system to investigate the feasibility of using inclined plate settlers (IPSs) to upgrade the secondary clarifier for bulking sludge recovery in the high-Rate microaerobic activated sludge (MAS) process that achieved enormous reduction in aeration energy consumption during domestic wastewater treatment. Compared to bulking sludge concentration (1.2–4.2 g/L) (and thus varied sludge zone settling velocities), both the experimental results and the theoretical predictions demonstRated that the plate length-to-spacing (L/D) ratio (3.75–15) of the IPSs likely plays a decisive role in determining its treatment capacity of the IPSs for bulking sludge recovery. The theoretical model was finally simplified to predict the critical Surface Loading Rate of the IPSs as a function of the L/D ratio. The maximum biomass concentration in the micro-aeration tank of the high-Rate MAS process was set at 4.5 g/L to assure effective sludge/water separation and bulking sludge recovery. Lastly, the continuous operation of the high-Rate MAS-IPS process over a lengthy period achieved stable effluent turbidity of 28%.
P. Guerra - One of the best experts on this subject based on the ideXlab platform.
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Occurrence and fate of four novel brominated flame retardants in wastewater treatment plants
Environmental Science and Pollution Research, 2014Co-Authors: M. Kim, P. Guerra, M. Alaee, S. A. SmythAbstract:Four novel brominated flame retardants (NBFRs), i.e., decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB) were studied in 377 liquid samples and 288 solid samples collected from 20 wastewater treatment plants. Lagoon, primary, secondary, and advanced treatment processes were included, in order to investigate NBFR occurrence and the effects of WWTP operational conditions on NBFR removal. Median influent and effluent levels were 14 to 3,700 and 1.0 to 180 pg/L respectively, with DBDPE being the highest in both. Overall median removal efficiencies for DBDPE, BTBPE, HBB, and PBEB across all process types were 81 to 93, 76 to 98, 61 to 97, and 54 to 97 %, respectively with advanced treatment processes obtaining the best removals. NBFRs removal was related to retention time, Surface Loading Rate, and biomass concentration. Median NBFR levels in treated biosolids were 80 to 32,000 pg/g, influenced by solids treatment processes.
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Parameters affecting the occurrence and removal of polybrominated diphenyl ethers in twenty Canadian wastewater treatment plants
Water research, 2013Co-Authors: Minhee Kim, P. Guerra, M. Theocharides, K. Barclay, Shirley Anne Smyth, Mehran AlaeeAbstract:This study determined PBDE levels in influent, primary effluent, and final effluent collected from diverse treatment processes including four aeRated lagoons, two facultative lagoons, four primary treatments, eight secondary biological treatments and two advanced treatments. Parameters examined for correlation included seasonal temperature, community sizes, industrial inputs, and operational conditions. PBDE levels in influent were 21-1000 ng/L (median 190 ng/L). Higher concentrations in influent samples were found during summer, and in WWTPs which treated leachate and higher proportions of industrial wastewater vs. residential wastewater. Final effluent levels ranged between 3 and 270 ng/L (median 12 ng/L). Among all congeners, the sum of BDE-209, -47 and -99 accounted for 79 and 71% of total PBDEs in influent and final effluent, respectively, with BDE-209 having the highest proportion. Median removal efficiencies for all process types exceeded 90% except primary treatment at 70%. PBDE levels and removals were correlated to the levels and removals of conventional parameters that represent wastewater strength, such as chemical oxygen demand and total suspended solids. The role of the primary clarifier was significant (∼82% removal) and removal was associated with hydraulic retention time (HRT) and Surface Loading Rate. Best removal of PBDEs was achieved at greater than 2000 mg/L mixed liquor suspended solids (MLSS), longer than 10 h of HRT, and 9 days of solids retention time.
Mehran Alaee - One of the best experts on this subject based on the ideXlab platform.
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Parameters affecting the occurrence and removal of polybrominated diphenyl ethers in twenty Canadian wastewater treatment plants
Water research, 2013Co-Authors: Minhee Kim, P. Guerra, M. Theocharides, K. Barclay, Shirley Anne Smyth, Mehran AlaeeAbstract:This study determined PBDE levels in influent, primary effluent, and final effluent collected from diverse treatment processes including four aeRated lagoons, two facultative lagoons, four primary treatments, eight secondary biological treatments and two advanced treatments. Parameters examined for correlation included seasonal temperature, community sizes, industrial inputs, and operational conditions. PBDE levels in influent were 21-1000 ng/L (median 190 ng/L). Higher concentrations in influent samples were found during summer, and in WWTPs which treated leachate and higher proportions of industrial wastewater vs. residential wastewater. Final effluent levels ranged between 3 and 270 ng/L (median 12 ng/L). Among all congeners, the sum of BDE-209, -47 and -99 accounted for 79 and 71% of total PBDEs in influent and final effluent, respectively, with BDE-209 having the highest proportion. Median removal efficiencies for all process types exceeded 90% except primary treatment at 70%. PBDE levels and removals were correlated to the levels and removals of conventional parameters that represent wastewater strength, such as chemical oxygen demand and total suspended solids. The role of the primary clarifier was significant (∼82% removal) and removal was associated with hydraulic retention time (HRT) and Surface Loading Rate. Best removal of PBDEs was achieved at greater than 2000 mg/L mixed liquor suspended solids (MLSS), longer than 10 h of HRT, and 9 days of solids retention time.