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Huang J.J.,Tianjin University | Gao X.,Tianjin University | Balch G.,Center for Alternative Wastewater Treatment | Wootton B.,Center for Alternative Wastewater Treatment | And 2 more authors.
Ecological Engineering | Year: 2015

With the increasing number of constructed wetlands being built, the modelling of wetland function and performance is valuable. This work examines the efficacy of applying a numeric model (SubWet 2.0) originally designed for horizontal subsurface flow wetlands to model wastewater treatment within vertical subsurface flow constructed wetlands (VSSF-CWs). The treatment efficiencies of two VSSF-CWs with substantially different influent characteristics, one in Canada and one in China, were modelled with SubWet 2.0 and simulated values were then compared to observed values to determine how closely SubWet 2.0 reflects the actual observed performance of these wetlands. The model was calibrated to each wetland with observed data that had been collected prior to the simulations. The correlation coefficient (R) and Nash-Sutcliff coefficient of efficiency (NSE) were used to evaluate the modelling performance for 5-day biochemical oxygen demand (BOD5), ammonium nitrogen, nitrate nitrogen and total phosphorous (TP). The results showed that the modelling performance for TP and BOD5 was better for these parameters than that observed for ammonium nitrogen and nitrate nitrogen for either of the two wetlands. For TP and BOD5, the correlation coefficient R achieved a value of 0.79 for the wetland receiving stormwater and exceeded this value for the Canadian wetland receiving domestic wastewaters. For nitrate nitrogen, the wetland treating domestic waste showed a correlation coefficient R as high as 0.97, while the wetland treating stormwater runoff had a correlation coefficient R of 0.48. For ammonium nitrogen, both wetlands showed low correlation coefficients with values of 0.70 and 0.60 for domestic wastewater and for stormwater runoff, respectively. This study demonstrated that SubWet 2.0 is suitable for the modelling of VSSF-CWs. The two case studies, with substantial differences in the characteristcs of the influents, demonstrated that Subwet 2.0 is a versatile and robust tool for modelling of constructed wetlands. © 2014 Published by Elsevier B.V.

Snow A.,Queens University | Snow A.,Golder Associates | Anderson B.,Queens University | Wootton B.,Center for Alternative Wastewater Treatment
Environmental Reviews | Year: 2012

The growing of finfish, crustaceans, molluscs, and aquatic plants is termed aquaculture and it is currently the fastest growing animal food producing sector in the world. Flow-through aquaculture facilities are the most commonly used production system for the culture of salmonids. Flow-through land-based aquaculture facilities place great demands on water resources because they require large volumes of high quality source water to grow fish and they also discharge their wastewaters into the aquatic environment. The main source of waste in aquaculture wastewaters is the addition of formulated feed to the culture structure. Discharge of untreated aquaculture wastewaters can lead to physicochemical and biological degradation of receiving waters. Despite advances in feed quality and feeding practices, the treatment of wastewaters from flow-through land-based aquaculture facilities is a necessary practice. Conventional wastewater treatment from flow-through land-based aquaculture facilities has focused on gravitational sedimentation and mechanical screening of the wastewater, which successfully addresses the particulate fraction of the waste. In the past decade, the use of subsurface flow constructed wetlands (SSFCWs), which treat both the particulate and the dissolved fraction of the waste have been gaining attention for the treatment of wastewater from flow-through land-based salmonid farms. Existing studies have demonstrated that SSFCWs have the potential to successfully remove solids, oxygen demanding materials and nutrients from flow-through land-based salmonid wastewaters. © 2012 Published by NRC Research Press.

Yates C.N.,University of Waterloo | Varickanickal J.,University of Waterloo | Cousins S.,University of Waterloo | Wootton B.,Center for Alternative Wastewater Treatment
Ecological Engineering | Year: 2016

The purpose of this study was to determine how well Carex aquatilis would intake nitrogen to remove it from municipal wastewater with decreasing temperatures and light, simulating summer and fall conditions in Baker Lake, Nunavut. Two trials were conducted, one at 0-5 °C and another at 5-10 °C in a controlled environmental chamber with parallel planted and unplanted planted microcosms. This study specifically examined reduction rates for ammonia, (NH3-N), nitrate (NO3 - -N), nitrite (NO2 - -N) and Total Kjeldahl Nitrogen (TKN). Wastewater was pumped at a rate of 27 L/day and influent and effluent were sampled twice per week for four weeks. Our results showed that the planted trials outperformed the controlled trials at both temperature regimes. In particular, there was a 98% decrease in NH3-N concentration for the 5-10 °C and 78% decrease for the 0-5 °C trial. We believe direct uptake by the plant is the reason for the removal. The planted system also showed a 92 percent increase in SO4 2- -S concentration (p < 0.01). Further research needs to be completed to determine how effective horizontal subsurface constructed wetlands are when built on shallow soil for extreme cold climate constructed wetlands. © 2016 Elsevier B.V.

Yates C.N.,University of Waterloo | Wootton B.C.,Center for Alternative Wastewater Treatment | Murphy S.D.,University of Waterloo
Ecological Engineering | Year: 2012

The treatment of municipal wastewater can be problematic in the remote cold climate environment of the Canadian Arctic, because of a variety of operational, financial, and technical and bureaucratic reasons. As a result, treatment facilities for many communities are thought to only achieve preliminary to primary treatment of municipal wastewater; wastewater often being discharged directly onto the tundra. In this study we provide the first season long study of tundra wetland systems in the Canadian Arctic. In 2008, we studied the performance of six wetland systems used for wastewater treatment in the Kivalliq Region of Nunavut, Canada. The wetland systems studied services communities of approximately 320-2300 residents, including commercial and government buildings, but generally minimal industry. In total, the systems receive a flow rate of approximately 28-163m 3/day of wastewater. We observed average weekly percent reduction in all parameters, with deviations immediately after snow-melt and at the beginning of freeze-up. For the six parameters monitored we observed reductions of 47-94% cBOD 5, 57-96% COD, 39-98% TSS, >99% TC, >99% E. coli, 84-99% NH 3-N and 80-99% TP. In three of the systems, the water discharged from the wetlands and into the receiving environment maintained similar concentrations, and significant similarities in NH 3-N and TP as observed in the natural background concentrations of nearby wetlands. The performance of tundra wetlands to treat the wastewater demonstrates that they are an appropriate technology for remote Canadian Arctic communities. This study also exemplifies the ability of natural systems to act as sinks and transformers, acknowledging that mechanistic assessments will be required to identify primary processes involved in the treatment of Arctic wastewater. © 2012 Elsevier B.V.

Pouladi S.F.,Queens University | Anderson B.C.,Queens University | Wootton B.,Center for Alternative Wastewater Treatment | Rozema L.,Aqua Treatment Technologies
Water (Switzerland) | Year: 2016

The dissolved salt ions that are not absorbed during irrigation of greenhouse crops are gradually accumulated in the nutrient solution resulting in levels of salinity high enough to damage the crops. This water salinity presents operational and environmental challenges as the nutrient-rich greenhouse effluent should be discharged to the environment when deemed unsuited for irrigation. In this pilot-scale study, the potential of passive salt reduction (phytodesalination) in gravel and wood-chip flow-through reactors was evaluated using seven plant species including Schoenoplectus tabernaemontani, Andropogon gerardii, Typha angustifolia, Elymus canadensis, Panicum virgatum, Spartina pectinata and Distichlis spicata along with an unplanted control reactor. While the unplanted system outperformed the planted units with gravel media, the wood-chip bioreactors with S. tabernaemontani and S. pectinata improved the greenhouse effluent reducing the solution conductivity (EC) by a maximum of 15% (average = 7%). S. tabernaemontani and D. spicata showed higher accumulated contents of Na+ and Cl- in comparison with T. angustifolia and S. pectinata. Overall, S. tabernaemontani was selected as the most capable species in the wood-chip bioreactors for its better salt management via EC reduction and salt accumulation. It was however concluded that further treatment would be required for the greenhouse effluent to meet the stringent irrigation water quality guidelines in order not to pose any adverse effects on sensitive crops. Finally, the present hydraulic residence time (HRT = 3.7 days) and the solution salinity concentration were identified as the potential factors that may be limiting the efficiency of plant salt uptake, emphasizing the need for conducting more research on the optimization and enhancement of passive desalination systems for the greenhouse effluent. © 2016 by the authors.

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