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In this study, the effect of CuO nanoparticles (NPs) on partial nitrification (PN) process was investigated at various pH values. The shortand long-term experiments were carried out in six identical reactors, with or without CuO NPs, at pH values of 6.5, 8.0 and 10.0. The ammonia oxidation, reaction rates, copper content, and the microbial community were investigated. The results of this work suggested that CuO NPs inhibited the ammonia oxidation by aerobic ammonia-oxidizing bacteria (AOB), under both the acid and alkali conditions. AOB could resist the acid condition but was significantly suppressed when CuO NPs was fed, and the low pH did not aggravate the inhibition level. Almost all the bacteria lost bioactivity under the pH as 10.0, while anaerobic ammonia-oxidizing bacteria survived. The acid condition increased the Nitrosomonas relative abundance while the alkali condition lowered it. More than 60% of the supplied CuO NPs was discharged via effluent. [ABSTRACT FROM AUTHOR]

Laboratory bench-scale anoxic/aerobic reactors with complete mix and continuous flow conditions were operated with high-strength synthetic wastewater to achieve simultaneous COD and nitrogen removal. High concentrations of organic carbon and nitrogen can be found in slaughterhouse, dairy, and food processing wastewaters, and also in some landfill leachates. Therefore, the goal of this study is to find a simple, efficient, reliable, cost-effective, and general solution for organic carbon and ammonia removal from streams with high influent concentrations of more than 5000 mg/L COD and 250 mg/L NH3–N. The highest COD (97%) and NH3–N (91%) removal efficiencies were obtained with initial COD and ammonia concentrations of 5211 mg/L and 262.8 mg/L NH3–N with volumetric loading rates of 11.26 kg COD/m3 d and 0.57 kg NH3–N/m3 d for COD and ammonia, respectively. Anaerobic oxidation is the main COD removal pathway in a simultaneous anaerobic oxidation/partial nitrification–denitrification (SAO/PND) system, and nitrogen removal significantly occurs via bacterial assimilation and partial nitrification–denitrification pathways. There are several advantages for this proposed SAO/PND system from a practical point of view, such as feasibility of simultaneous COD and nitrogen removal in a single reactor; simple operation; flexibility and practicality of this system as a general solution and cost effectiveness. [ABSTRACT FROM AUTHOR]

Improper design and maintenance of stormwater ponds (SWPs) may lead to hypoxic conditions, poor water quality and the production of hydrogen sulfide (H2S). The objective of this study is to develop a comprehensive understanding of hypoxic conditions of SWPs, with a focus on the potential for H2S production and emission. This study was conducted at two retention SWPs in Ottawa, Canada; a problematic pond with the propensity for H2S emission and a reference pond that did not demonstrate H2S emission. The investigation illustrated a significant impact of low dissolved oxygen (DO) concentrations, hypoxic conditions, on the concentration of total sulfides in the water column. Both ponds were shown to periodically experience hypoxic conditions at depth, especially during summer periods with less precipitation and across longer periods of winter, ice-covered conditions. The problem pond, however, was shown to experience lower DO and longer hypoxic conditions than the reference pond in both non-ice-covered and ice-covered conditions due to greater depth and a longer hydraulic retention time. Hypoxic conditions were initiated at the deepest locations in the problem pond and subsequently were spread across the entirety of the pond under winter, ice-covered conditions. Algal biomass (Chlorophyll-a) and soluble biochemical oxygen demand concentrations were shown to not likely be significant factors in the development of hypoxia in the H2S-generating pond. Algal blooms of colonial Chrysophyceae, Synura, a known mixotroph, were observed during ice-covered conditions in the problem pond possibly due to stress-coping mechanisms of algae. [ABSTRACT FROM AUTHOR]

Ammonia removal kinetics and solids' production performance of the bio-cord technology are studied in this research. Three nitrifying reactors housing different bio-cord substratum were operated at five different ammonia loading rates. All of the bio-cord substrata demonstrated stable and high ammonia-nitrogen removal efficiencies of 96.8 ± 0.9%, 97.0 ± 0.6% and 92.0 ± 0.4% at loading rates of 0.8, 1.6 and 1.8 g -N/m2 d, respectively. At these same loading rates, the bio-cord reactors housing the three substrata also showed low solids' production rates of 0.19 ± 0.03, 0.23 ± 0.02, 0.25 ± 0.03 g total suspended solids/d. A reduction of system stability, identified via fluctuating ammonia removal rates, was however observed for all substrata at loading rates of 2.1 and 2.4 g -N/m2 d. Further, the solids' production rates at these higher loading conditions were also observed to fluctuate for all substrata, likely indicating intermediate sloughing events. The effects of enhancing the air scouring of the bio-cord on the ammonia removal rate was shown to be dependent upon the substratum, while enhanced air scouring of the bio-cord was shown to stabilize the production of solids for all substrata. This study represents the first performance and optimization study of the bio-cord technology for low-carbon nitrification and shows that air scouring of the substratum reduces sloughing events at elevated loading and that the bio-cord technology achieves stable kinetics above conventional rates of 1 g -N/m2 d to values of 1.8 g -N/m2 d. [ABSTRACT FROM AUTHOR]

Increasingly stricter ammonia and nitrogen release regulations with respect to wastewater effluents are creating a need for tertiary treatment systems. The moving bed biofilm reactor (MBBR) is being considered as an upgrade option for an increasing number of wastewater treatment facilities due to its small footprint and ease of operation. Despite the MBBRs creation as a system to remove nitrogen, recent research on MBBR systems showing that the system's performance is directly related to carrier surface area and is irrespective of carrier shape and type has been performed exclusively on chemical oxygen demand (COD) removal systems. Furthermore, the influence of carrier type on the solids produced by MBBR systems has also been exclusively studied for COD removal systems. This work investigates the effects of three specific carrier types on ammonia removal rates, biofilm morphology, along with solids production and settleability of tertiary nitrifying MBBR systems. The study concludes that carrier type has no significant effect on tertiary nitrifying MBBR system performance under steady, moderate loading conditions. The research does however highlight the propensity of greater surface area to volume carriers to become clogged under high loading conditions and that the high surface area carriers investigated in this study required longer adjustment periods to changes in loading after becoming clogged. [ABSTRACT FROM PUBLISHER]

A mobile testing center was installed at a lagoon wastewater treatment plant (WWTP) at Terrebonne, Canada to investigate the rate of ammonia removal of attached growth treatment systems at 4°C and at low influent carbon concentrations. The testing center housed two laboratory-scale reactors, a pilot-scale BioStyr system (Veolia Water) and a pilot-scale moving bed bioreactor (MBBR) system (Veolia Water). Although the rates of laboratory-scale and the pilot-scale systems demonstrated that the exposure time to low temperature has a significant effect on the kinetics of the system, the ammonia removal rates of all the systems were shown to be significant at 4°C. A strong correlation was demonstrated between the rates of ammonia removal produced by the laboratory-scale reactors, the pilot BioStyr system and pilot MBBR system; thus verifying the scale-up capability of the laboratory-scale reactors and demonstrating that nitrifiers can achieve ammonia removal under cold temperature conditions for elapsed periods of time independent of the reactor design. Finally, the ammonia removal rates of the laboratory-scale systems, the BioStyr pilot system, and the MBBR pilot system were all accurately predicted by a recently proposed Theta model. [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, the Province of Ontario, Canada, launched a wastewater surveillance program to monitor SARS-CoV-2, inspired by the early work and successful forecasts of COVID-19 waves in the city of Ottawa, Ontario. This manuscript presents a dataset from January 1, 2021, to March 31, 2023, with RT-qPCR results for SARS-CoV-2 genes and PMMoV from 107 sites across all 34 public health units in Ontario, covering 72% of the province's and 26.2% of Canada's population. Sampling occurred 2-7 times weekly, including geographical coordinates, serviced populations, physico-chemical water characteristics, and flowrates. In doing so, this manuscript ensures data availability and metadata preservation to support future research and epidemic preparedness through detailed analyses and modeling. The dataset has been crucial for public health in tracking disease locally, especially with the rise of the Omicron variant and the decline in clinical testing, highlighting wastewater-based surveillance's role in estimating disease incidence in Ontario., (© 2024. The Author(s).)

We determined correlations between SARS-CoV-2 load in untreated water and COVID-19 cases and patient hospitalizations before the Omicron variant (September 2020-November 2021) at 2 wastewater treatment plants in the Regional Municipality of Peel, Ontario, Canada. Using pre-Omicron correlations, we estimated incident COVID-19 cases during Omicron outbreaks (November 2021-June 2022). The strongest correlation between wastewater SARS-CoV-2 load and COVID-19 cases occurred 1 day after sampling (r = 0.911). The strongest correlation between wastewater load and COVID-19 patient hospitalizations occurred 4 days after sampling (r = 0.819). At the peak of the Omicron BA.2 outbreak in April 2022, reported COVID-19 cases were underestimated 19-fold because of changes in clinical testing. Wastewater data provided information for local decision-making and are a useful component of COVID-19 surveillance systems.