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Nutrient removal is one of the primary goals of wastewater treatment and large amounts of ammonia are present throughout the wastewater treatment process. Conventional ammonia removal technologies are energy intensive and do not result in recoverable forms of the nutrient. Anaerobic dewatering side-streams are the liquid recovered during the biosolids dewatering processes following anaerobic digestion. The dewatering side-streams contain high concentrations of ammonia (~1000 mg/L NH4-N) making them an excellent candidate for resource recovery technologies. In this study electrodialysis (ED) was investigated for ammonia (NH4-N) recovery from anaerobic dewatering side-streams with an emphasis on fouling and scaling control on ion exchange membranes (IEMs). The experimental set-up consisted of 3 bench-scale electrodialyzers operating in parallel. The dewatering side-stream (centrate) was collected directly from centrifuges at a local WWTP and pretreated using a 0.3-mm screen. Electrodialyzer operation over 2.25 hrs achieved 95% NH4-N removal and the ammonia separation rate was slowed down by the concentration gradient between concentrate and diluate streams. A combined 269 hrs of operation during fouling experiments showed that electrodialysis (ED) performance decreased over time due to IEM fouling and thus clean-in-place (CIP) procedures was conducted every 60-120 hrs to restore the ED effectiveness. The two stage CIP procedures consisted of a NaCl Clean (5% NaCl, 2 hrs recirculation) and an Acid Clean (5% v/v HCl, 2 hrs recirculation). The NaCl Clean targeted organic fouling and the Acid Clean removed scales that precipitated on the IEMs. CIP procedures were able to recover 84-90% of the initial separation efficiency, the permanent loss in separation efficiency indicating that a portion of IEM fouling (10-16%) is irreversible. The higher applied voltage condition (7.5 V) showed faster fouling rates compared to low voltage conditions (4.5 V), while the degree of irreversible fouling was independent of the applied voltage. Organic fouling and inorganic scaling were individually quantified during CIP procedures using electrochemical impedance spectroscopy (EIS). While both fouling and scaling contributed significantly to the overall increase in the IEM stack resistance (63% scale formation, 37% organic fouling), inorganic scaling was found to play a more important role in reducing the separation rate in ED. ICP and SEM-EDS analysis identified the scale that formed on the surface of the IEMs as mostly of CaCO3 precipitation with smaller amounts of struvite. This finding indicates that the pretreatment of dewatering side-streams should be more focused on removing divalent cations (Ca2+ and Mg2+), but also still consider organic foulant removal for its treatment in ED. Since organic fouling primarily affects anion exchange membranes (AEMs), the impacts of fouling were investigated on two types of AEMs (AR908, AR204). Fouling experimentation showed minor differences in current density and separation efficiency over 269 hrs of operation, with AR204 AEMs showing signs of worse irreversible fouling. Particle size analysis of centrate suggested that large suspended particles could obstruct electrodialyzer chambers. Screening pretreatment (0.3 mm) effectively removed large particles and mitigated clogging issues without having to increase intermembrane distances. The experimental results suggest that ED is a promising technology for recovering ammonia from nutrient rich wastewaters. ED was able to efficiently achieve high levels of ammonia separation from centrate, while fouling was shown to be manageable using CIPs at reasonable intervals. Overall ED was shown to be an effective way to recover ammonia from dewatering side-streams, but pretreatments targeting scaling and organic fouling could better mitigate performance losses due to fouling and further improve the process. / Thesis / Master of Applied Science (MASc)

No / Effective integrated water management is a key component of the World Water Vision and the way in which aspirations for water equity may be realized. Part of the vision includes the promotion of sustainability of water systems and full accountability for their interaction with other urban systems. One major problem is that “sustainability” remains an elusive concept, although those involved with the provision of urban wastewater systems now recognize that decisions involving asset investment should use the “triple bottom line” approach to society, the economy, and the environment. The Sustainable Water Industry Asset Resource Decisions project has devised a flexible and adaptable framework of decision support processes that can be used to include the principles of sustainability more effectively. Decision mapping conducted at the outset of the project has shown that only a narrow range of criteria currently influence the outcome of asset investment decisions. This paper addresses the concepts of sustainability assessment and presents two case studies that illustrate how multicriteria decision support systems can enhance the assessment of the relative sustainability of a range of options when decisions are being made about wastewater asset investment.

Recent studies have shown that Ebola virus can persist in wastewater, and the potential for the virus to be aerosolized and pose a risk of inhalation exposure has not been evaluated. We considered this risk for three wastewater systems: toilets, a lab-scale model of an aeration basin, and a lab-scale model of converging sewer pipes. We measured the aerosol size distribution generated by each system, spiked Ebola virus surrogates into each system, and determined the emission rate of viruses into the air. While the number of aerosols released ranged from 105 to 107 per flush from the toilets or per minute from the lab-scale models, the total volume of aerosols generated by these systems was ~10-8 to 10-7 mL per flush or per minute in all cases. The Ebola virus surrogates MS2 and Phi6, spiked into toilets at an initial concentration of 107 PFU mL-1, were not detected in air after flushing. Airborne concentrations of MS2 and Phi6 were ~20 PFU L-1 and ~0.1 PFU L-1, respectively, associated with the aeration basin and sewer models. This corresponds to emission rates of 547 PFU min-1 and 3.8 PFU min-1 of MS2 and Phi6, respectively, for the aeration basin and 79 PFU min-1 and 0.3 PFU min-1 for the sewer model. Since information on the aerosolization of Ebola virus is quite limited, these emission rates can greatly help inform risk assessment of inhalation exposure to Ebola virus. / Master of Science

The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h⁻¹ on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO⁻) and the inhibitory effects of its conjugate acid, nitrous acid (HNO₂). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass. / Master of Science

Yes / This paper describes a new heat transfer parameterisation between wastewater and insewer air based on understanding the physical phenomena observed in free surface wastewater and in-sewer air. Long-term wastewater and in-sewer air temperature data were collected and studied to indicate the importance of considering the heat exchange with in-sewer air and the relevant seasonal changes. The new parameterisation was based on the physical flow condition variations. Accurate modelling of wastewater temperature in linked combined sewers is needed to assess the feasibility of in-sewer heat recovery. Historically, the heat transfer coefficient between wastewater and in-sewer air has been estimated using simple empirical relationships. The newly developed parameterisation was implemented and validated using independent long-term flow and temperature datasets. Predictive accuracy of wastewater temperatures was investigated using a Taylor diagram, where absolute errors and correlations between modelled and observed values were plotted for different site sizes and seasons. The newly developed coefficient improved wastewater temperature modelling accuracy, compared with the older empirical approaches, which resulted in predicting more potential for heat recovery from large sewer networks. For individual locations, the RMSE between observed and predicted temperatures ranged between 0.15 and 0.5 °C with an overall average of 0.27 °C. Previous studies showed higher RMSE ranges, e.g., between 0.12 and 7.8 °C, with overall averages of 0.35, 0.42 and 2 °C. The new coefficient has also provided stable values at various seasons and minimised the number of required model inputs.

Wastewater treatment is essential to protecting the environment and human welfare. Although chlorination is widely used, the environmental and health concerns associated with chlorine are growing. Treatment facilities are implementing alternative technologies, though the cost and efficiency associated with these practices leave much room in the wastewater field for innovation. Hydropath Technologies Limited introduced a piece of equipment that uses the properties of a transformer to pass an alternating electric current through the pipe and into the contents of the channel. Hydroflow claims that the charged microorganisms react with the oppositely charged water molecule to force osmosis and kill the cell. Disinfection capabilities of three Hydroflow models with varying voltages are tested using municipal wastewater from the secondary clarifier using Escherichia coli concentration as the unit for quantification. After testing the results surrounding theses experiments cannot support the hypothesis that the Hydroflow technology could replace chlorination for municipal wastewater disinfection.

Cette thèse présente divers aspects du polissage des eaux usées de galvanoplastie par des zones humides artificielles : analyse de la performance, étude de la configuration et de la mise en œuvre, influence de différentes sources de carbone, évolution du substrat, l'analyse des plantes et des problèmes de conception.Les objectifs de ce travail sont triples: (i) étudier la faisabilité du polissage des effluents de la galvanoplastie, (ii) étudier l'influence des systèmes opérationnels, des plantes, du substrat et de la charge des eaux usées, (iii) comprendre les mécanismes conduisant à une diminution de la charge métallique dans des microcosmes de zones humides construites.Ce travail a fourni de nouvelles informations et élargi les connaissances actuelles sur le traitement des eaux usées industrielles dans les zones humides artificielles. En fait, il s'agit, à notre connaissance, de la première étude concernant l'élimination des métaux et du cyanure d'eaux usées par des zones humides artificielles en écoulement de sub-surface. / This thesis presents various aspects of polishing the electroplating wastewater in constructed wetlands: analysis of the performance, study on the operation and configuration effects, effects of various carbon sources, analysis of the substrate (bed media), analysis of plants, and design issues.The goals of the experiment were to: (i) study the feasibility of polishing electroplating effluent, (ii) study the effect of operating schemes, plants, bed media and wastewater strength, (iii) to elucidate metal removal mechanisms in the CW microcosms.This study furnished new information and expanded the existing knowledge on industrial wastewater treatment in constructed wetlands. In fact, this is, to the best knowledge, the first publication studying the removal of metals and cyanide from electroplating wastewater in subsurface flow constructed wetlands. The aim of this study was to study the polishing of the electroplating wastewater pretreated using physical-chemical methods.

Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of pollutants is higher than the required national technical regulation on the effluent of the natural rubber processing industry (QCVN 01:2008/BTNMT). Thus, this paper summarizes various technologies and methods currently applied for the treatment of latex processing wastewater in Vietnam. Additionally, the new effective methods being researched and applied in Thailand and Malaysia are also mentioned (countries with the highest production of natural rubber in the world). This paper also provides a screening of treatment technologies for reducing environmental pollution and contributing to high-quality effluent for meeting the required standard. / Cao su là một trong những cây trồng chính và đóng vai trò quan trọng trong nền kinh tế của miền Đông Nam Bộ, Việt Nam. Sản phẩm từ cây cao su thiên nhiên tại Việt Nam chủ yếu là xuất khẩu (khoảng 90%), tuy nhiên chỉ mới là dạng cao su thiên nhiên sơ chế. Quá trình sơ chế mủ cao su thiên nhiên thải bỏ một lượng lớn nước thải vào môi trường. Ở Việt Nam, hiện tại có rất nhiều công nghệ xử lý nước thải sơ chế mủ cao su đã được thiết lập và vận hành. Tuy nhiên, nồng độ ô nhiễm trong nước thải sau quá trình xử lý còn cao so với tiêu chuẩn yêu cầu (QCVN 01:2008/BTNMT). Vì vậy, bài báo này tóm tắt những công nghệ và phương pháp khác nhau được sử dụng để xử lý nước thải sơ chế mủ cao su tại Việt Nam gần đây. Thêm vào đó, những phương pháp mới và hiệu quả đang được nghiên cứu và áp dụng tại Malaysia và Thái Lan, những quốc gia có sản lượng sản xuất mủ cao su cao nhất trên thế giới cũng được giới thiệu. Bài báo này cũng cung cấp sự đa dạng của những phương pháp xử lý nhằm giảm thiểu ô nhiễm môi trường và góp phần đảm bảo chất lượng nước đầu ra đạt tiêu chuẩn cho phép.

This thesis presents various aspects of polishing the electroplating wastewater in constructed wetlands: analysis of the performance, study on the operation and configuration effects, effects of various carbon sources, analysis of the substrate (bed media), analysis of plants, and design issues.The goals of the experiment were to: (i) study the feasibility of polishing electroplating effluent, (ii) study the effect of operating schemes, plants, bed media and wastewater strength, (iii) to elucidate metal removal mechanisms in the CW microcosms.This study furnished new information and expanded the existing knowledge on industrial wastewater treatment in constructed wetlands. In fact, this is, to the best knowledge, the first publication studying the removal of metals and cyanide from electroplating wastewater in subsurface flow constructed wetlands. The aim of this study was to study the polishing of the electroplating wastewater pretreated using physical-chemical methods.