Bruce C. Anderson

Urbanization, land use, and water quality in Shanghai 1947-1996

The paper undertakes a preliminary investigation into the relationship between water quality and urbanization as well as the changing patterns of land use within Shanghai. Longitudinal changes to water quality at various points along the course of the Huangpu River are analysed and compared to changes in the rates of urbanization and changes in land uses. The results reveal that rapid urbanization corresponds with rapid degradation of water quality. It also shows that urban land uses are positively correlated with the decline in water quality. A regression model shows that close to 94% of the variability in water quality classifications is explained by industrial land area. The paper concludes with the need for comprehensive land use planning as a way of protecting valuable water resources.

Evaluating and modeling biogas production from municipal fat, oil, and grease and synthetic kitchen waste in anaerobic co-digestions.

The feasibility of using synthetic kitchen waste (KW) and fat, oil, and grease (FOG) as co-substrates in the anaerobic digestion of waste activated sludge (WAS) was investigated using two series of biochemical methane potential (BMP) tests. Ranges of ideal substrate to inoculum (S/I) ratio were determined for the FOG (0.25-0.75) and KW (0.80-1.26) as single substrates in the first experiment. The second experiment, which estimated the methane production performances of FOG and KW as co-substrates for WAS co-digestion, was conducted based on the optimal parameters selected from the results of the first experiment. Results indicated that co-digestions with FOG and KW enhanced methane production from 117±2.02 mL/gTVS (with only WAS) to 418±13.7 mL/gTVS and 324±4.11 mL/gTVS, respectively. FOG exhibited more biogas production than KW as co-substrate. Non-linear regression results showed that co-substrate addition shortened the lag phases of organic biodegradation from 81.8 (with only WAS) to 28.3 h with FOG and 3.90 h with KW.

Laboratory investigation of ethanol production from municipal primary wastewater solids

Abstract Ethanol can be produced from a number of renewable resources such as starches, sugars, or lignocellulosic materials. Lignocellulosic waste materials such as municipal wastes or wastepaper are defined as such because they contain cellulose in combination with lignin. The cellulose component in these materials can be converted to ethanol in a two-step process where the cellulose is first converted to glucose sugars by hydrolysis (saccharification); the resulting sugars can in turn be converted to ethanol by fermentation. A preliminary investigation was performed to assess the conversion of the cellulosic component of municipal primary wastewater solids to ethanol. Primary wastewater solids collected from two full-scale facilities were tested. A laboratory experimental set-up was designed in order to perform the necessary conversions. The primary wastewater solids were characterized to contain 10% cellulose and 26% lignin. Conversion of the cellulose to glucose was achieved by Trichoderma reesei cellulases in enzyme hydrolysis. These experiments demonstrated that higher substrate concentrations, temperatures and enzyme concentrations resulted in higher rates of reaction. Conversion of the glucose to ethanol during fermentation was accomplished by the action of yeasts from Saccharomyces cerevisiae. The two conversion processes were then combined in the same vessel to obtain simultaneous conversion in a process known as simultaneous saccharification and fermentation (SSF). SSF experiments employed the cellulase system from Trichoderma reesei QM9414 and Saccharomyces cerevisiae in the same vessel and achieved ethanol concentrations between 1.5 and 2.3 g/l from nutrient media containing 100 g/l primary wastewater solids. This corresponded to overall conversion efficiencies of cellulose to ethanol in the range of 17–60% based on theoretical values.

Adaptation of a Storm Drainage System to Accommodate Increased Rainfall Resulting from Climate Change

Extreme rainfalls in southern Ontario may increase significantly as a result of climate change. This study was designed to determine the impact of a 15% increase in design rainfall intensities on drainage of a typical urban catchment and to investigate adaptive measures. A calibrated model (PCSWMM 2000) was used to: (1) determine the system performance under current and climate-changed design rainfalls; and (2) calculate the magnitudes of various adaptive measures required to reduce the peak discharge to current levels. For this type of catchment, effective retrofit options that provide the required peak discharge reductions included downspout disconnection (50% of connected roofs), increased depression storage (by 45 m3/impervious hectare), and increased street detention storage (by 40m3/impervious hectare).

Effects of ultrasonic and thermo-chemical pre-treatments on methane production from fat, oil and grease (FOG) and synthetic kitchen waste (KW) in anaerobic co-digestion.

The effects of ultrasonic and thermo-chemical pre-treatments on the methane production potential of anaerobic co-digestion with synthetic kitchen waste (KW) or fat, oil and grease (FOG) were investigated. Non-linear regressions were fitted to accurately assess and compare the methane production from co-digestion under the various pre-treatment conditions and to achieve representative simulations and predictions. Ultrasonic pre-treatment was not found to improve methane production effectively from either FOG co-digestion or KW co-digestions. Thermo-chemical pre-treatment could increase methane production yields from both FOG and KW co-digestions. COD solubilization was found to effectively represent the effects of pre-treatment. A comprehensive evaluation indicated that the thermo-chemical pre-treatments of pH=10, 55°C and pH=8, 55°C provided the best conditions to increase methane production from FOG and KW co-digestions, respectively. The most effective enhancement of biogas production (288±0.85mLCH(4)/g TVS) was achieved from thermo-chemically pre-treated FOG co-digestion, which was 9.9±1.5% higher than FOG co-digestion without thermo-chemical pre-treatment.

Fecal Indicator Bacteria Variability in Samples Pumped from Monitoring Wells

The detection of microbiological contamination in drinking water from groundwater wells is often made with a limited number of samples that are collected using traditional geochemical sampling protocols. The objective of this study is to examine the variability of fecal indicator bacteria, as observed using discrete samples, due to pumping. Two wells were instrumented as multilevel piezometers in a bedrock aquifer, and bacterial enumeration was conducted on a total of 166 samples (for total coliform, fecal coliform, Escherichia coli, and fecal streptococci) using standard membrane filtration methods. Five tests were conducted using pumping rates ranging from 0.3 to 17 L/min in a variety of purging scenarios, which included constant and variable (incremental increase and decrease) flow. The results clearly show a rapid and reproducible, 1 to 2 log-unit decrease in fecal indicator bacteria at the onset of pumping to stabilized, low-level concentrations prior to the removal of three to five well volumes. The pumping rate was not found to be correlated with the magnitude of observed bacterial counts. Based on the results, we suggest sampling protocols for fecal indicator bacteria that include multiple collections during the course of pumping, including early-time samples, and consider other techniques such as microscopic enumeration when assessing the source of bacteria from the well-aquifer system.

Pilot-scale comparison of two hybrid-passive landfill leachate treatment systems operated in a cold climate.

Hybrid-passive landfill leachate treatment systems employ active pretreatment to remove dissolved inorganic constituents and decrease the oxygen demand of the leachate prior to treatment in a passive system. In a 1-year pilot-scale study, two passive treatment systems - a peat and wood shaving biological trickle filter and a sand and gravel constructed wetland - were installed to treat leachate from the Merrick Landfill in North Bay, Ontario, Canada. Leachate was pretreated in a fixed-film aerobic reactor, which provided reductions in COD (26%), and masses of ammonia (21%), Al (69%), Ca (57%), Fe (73%) and Sr (37%). A comparison of the performance of the hybrid-passive treatment systems indicated different extents of heterotrophic nitrification; the peat and wood shaving filter removed 49% of the ammonia and nitrified 29%, while the constructed wetland removed 99% of the ammonia and nitrified 90%. Hybrid-passive landfill leachate treatment was determined to be feasible in cold climates.

Tastes and Odors in Kingston's Municipal Drinking Water: A Case Study of the Problem and Appropriate Solutions

Abstract This paper describes a 1995 study conducted in Kingston, Ontario, commissioned by the water utility to quantify the degree of public concern over algae-induced tastes and odors (T/O) in local drinking water. These T/O episodes had been sporadic in the past, but were becoming more frequent as a result of changes occurring in the water source (Lake Ontario). Complaints to the utility had increased an estimated ten-fold from the previous year, due to a long-term T/O episode in the late summer/early fall of 1994. The utility was interested in gathering information both locally and provincially on the impacts and effects of these episodes, which would be used to formulate a strategy for dealing with this problem in future. The results from this study played a key role in this process. From the results of a public opinion survey and a survey of strategies used by other utilities experiencing similar problems, it was concluded that, while the number of complaints increased during these periods, the degree of public concern was not substantial enough to warrant any significant changes in water treatment operations at this time. There was also little desire to increase public spending on water treatment. As well, it appears that the affected consumers were capable of dealing with this problem on an individual basis through use of water filtration pitchers in the home. It was recommended that a public education campaign be instituted by the utility, to better inform the public about these episodes and associated risks as they occurred. Further monitoring of the frequency of occurrence of these episodes was also suggested.

Behaviour and control of nutrients in the enhanced aerobic digestion process: Pilot‐scale studies

Abstract The fate and behaviour of nitrogen and phosphorus were examined in semi‐continuous pilot‐scale aerobic digestion of waste activated sludges from an Extended Aeration, biological nutrient removal facility and a High Rate, activated sludge facility. Due to nitrification in the poorly buffered digesters, mixed liquor pH (MLpH) levels as low as pH 3.5 were observed; to counteract this, chemical MLpH control was initiated, with the goals of enhanced metabolic activity and digester efficiency. The inorganic chemicals used for this purpose (Ca(0H)2 and NaHCO3) also had substantial effects on nitrogen and phosphorus forms and concentration; digester supernatant quality was directly influenced by reactor MLpH level and controlling chemical, for both nutrients. It was concluded that chemical control of MLpH, for the enhancement of aerobic digestion, is at the same time an effective method for the removal of nuisance nutrient species, and a means of ensuring efficient overall operation of the digester.

Biological mechanisms associated with triazophos (TAP) removal by horizontal subsurface flow constructed wetlands (HSFCW).

Triazophos (TAP) is a widely used pesticide that is easily accumulated in the environment due to its relatively high stability: this accumulation from agricultural runoff results in potential hazards to aquatic ecosystems. Constructed wetlands are generally considered to be an effective technology for treating TAP polluted surface water. However, knowledge about the biological mechanisms of TAP removal is still lacking. This study investigates the responses of a wetland plant (Canna indica), substrate enzymes and microbial communities in bench-scale horizontal subsurface-flow constructed wetlands (HSCWs) loaded with different TAP concentrations (0, 0.1, 0.5 and 5 mg · L(-1)). The results indicate that TAP stimulated the activities of superoxide dismutase (SOD) and peroxidase (POD) in the roots of C. indica. The highest TAP concentrations significantly inhibited photosynthetic activities, as shown by a reduced effective quantum yield of PS II (ΦPS II) and lower electron transport rates (ETR). However, interestingly, the lower TAP loadings exhibited some favorable effects on these two variables, suggesting that C. indica is a suitable species for use in wetlands designed for treatment of low TAP concentrations. Urease and alkaline phosphatase (ALP) in the wetland substrate were activated by TAP. Two-way ANOVA demonstrated that urease activity was influenced by both the TAP concentrations and season, while acidphosphatase (ACP) only responded to seasonal variations. Analysis of high throughput sequencing of 16S rRNA revealed seasonal variations in the microbial community structure of the wetland substrate at the phylum and family levels. In addition, urease activity had a greater correlation with the relative abundance of some functional microbial groups, such as the Bacillaceae family, and the ALP and ACP may be influenced by the plant more than substrate microbial communities.