Trihalomethane Formation in Water Treatment
Biological Treatment of a CTMP Effluent
Acidification of Small Lakes
Novel Wastewater Treatment Process
River Transport of Phosphorus and Metals
Groundwater Contamination from Manure Spreading
Screening Assay for Dioxins
Treatment of Wastewater in Developing Countries
Horseradish Peroxidase Catalyzed Phenol Removal
Landfill Leachate Treatment
Natural Degradation of Organochlorines
Sampling North-Temperate Lakes for Trophic Status
Decolouration and Detoxification of Wastewater
Bench-Scale Jar Tests
Metal Toxicity in Landfill Leachate Treatment
Thickening and Dewatering Sludges
Integrated River Basin Management
Degradation of Resin Acids
Effluent Quality of Lagoon-Based Systems

École Polytechnique scientist M. Prévost and colleagues studied the effects of ozonation and biological activated carbon (BAC) filtration on chlorine demand and the formation of trihalomethanes and total organic halide compounds. The study used the Sainte-Rose water treatment facility in Laval, Quebec, with a surface water influent having a dissolved organic carbon content of 6-7 mg/L. The results, published in the Canadian Journal of Civil Engineering, showed that ozonation marginally reduced short term chlorine demand but that BAC filtration reduced it by 40-55%. Ozonation reduced trihalomethanes and total organic halides by 48-60% and 39% respectively. Subsequent BAC filtration further reduced these by 20-34% and 16% respectively.

In a paper published in the Water Quality Research Journal of Canada, University of Quebec scientists H.W. Liu, S.N. Lo and H.C. Lavallée present basic equations based on the Monod kinetic model for a two-stage sequential anaerobic-aerobic treatment system. The effects of operating conditions on the behaviour of this system for the treament of a CTMP effluent were studied theoretically by these researchers. The study revealed that unstable operation of the anaerobic process could be due to the treatment being carried out in a time range in which the operation was very sensitive to the variation in either hydraulic retention time or mean cell age.

Environment Canada scientist M. Papineau surveyed 25 small lakes (less than five hectares area) in the area northwest of Quebec City to assess the chemical status of these lakes in relation to acidic deposition. About one-third of these lakes have very little neutralizing capacity and a relatively high concentration of aluminum. As described in the Water Quality Research Journal of Canada, the average concentration of hydrogen ions, sulfates, aluminum, colour, and dissolved organic carbon was higher in these small lakes than in a group of nearby lakes which are larger than five hectares.

University of Manitoba scientists S.K. Basu, T. Mino and J.A. Oleszkiewicz investigated the feasibility of utilizing the symbiotic relationship of bacteria related to sulfur metabolism for organic removal in a sludge blanket type reactor. The microaerophilic upflow sludge bed reactor relies on the interaction between sulfate reducing bacteria and microaerophilic sulfide oxidising bacteria, Beggiatoa, for organic matter removal. As reported in the Canadian Journal of Civil Engineering, maximum removal of total COD, filtered COD and suspended solids were 92%, 94%, and 87% respectively at a hydraulic retention time of 4.5 h. At a low hydraulic retention time of 2.5 h, a filtered COD removal efficiency of 89% could still be achieved.

National Water Research Institute scientists investigated the role of suspended sediments in the transport of phosphorus and metals in the Grand River and its tributary, the Nith River. T. Meyer and E. Delos found that about one-half the total phosphorus in the water was transported in the particulate form, of which about 20% is in a form that would be potentially available for biological utilization upon depletion of soluble phosphorus. As described in the Water Quality Research Journal of Canada, there was a lack of significant sample site differentiation in suspended sediments chemistry reflecting the absence of chemical and/or biological processing of particles in transit and the similarity of sediment sources.

Agriculture and Agri-Food Canada scientists C. Chang and T. Entz undertook research at Lethbridge, Alberta to determine the long-term effects of annual applications of cattle manure on nitrate accumulation and movement, and to assess the environmental impact of such a practice. Manure was applied annually at up to three times the recommended application rate to non-irrigated and irrigated clay loam soils over a twenty year period. As reported in the Journal of Environmental Quality, for non-irrigated soils, minimal leaching loss of NO3-N was observed below 1.5 m except for a year with unusually high precipitation. On irrigated soils, contamination of groundwater, even at the recommended manure application rate, was significant.

A series of environmental samples, comprising fly ash, caustic wash water from regeneration of a petrochemical reforming catalyst, fish hydrogenates, soil, and pulp mill sludge, were analysed for dioxin-like compounds by an assay involving competitive binding of a reference radioligand and an extract from the sample to mouse hepatic Ah receptor. The results, published in Environmental Science and Technology, by N.J. Bunce and colleagues from the University of Guelph and Wellington Laboratories, were compared with GC/MS. The bioassay generally gave higher dioxin equivalent values than GC/MS due to false positive values generated by coplanar PCBs and PAHs in the samples.

École Polytechnique scientist C.C. Delisle and colleagues from the Institut de recherche en biologie végétale, Montreal, and INRS-Eau investigated two economical wastewater treatment processes on a pilot scale in the sahelian region of Niger, Africa. These were combinations of a facultative lagoon and of ponds with the floating macrophytes water hyacinth or water lettuce. As described in the Water Quality Research Journal of Canada, the two processes proved to be efficient, reliable and adaptable to the local climate. The facultative lagoon was a reliable alternative to secondary treatment and the aquatic macrophyte ponds were useful for nitrogen removal.

At the CAWQ Eastern Symposium on Water Pollution Research, delegates heard a paper by I.D. Buchanan and J.A. Nicell describing the model which they developed for the kinetics of horseradish peroxidase (HRP) catalyzed removal of phenol from aqueous solution. In the process, the HRP molecule, activated by hydrogen peroxide, produces free radicals which diffuse into the bulk solution where they spontaneously react with the phenol to form polymers of high molecular weight and low solubility. These may be removed from the waste stream by sedimentation or filtration. The process is economically competitive with conventional oxidative treatment methods. The model developed by these McGill University scientists may be used to optimize the reactor configuration and operating procedures.

CH₂M Gore & Storrie scientist M.A. Warith investigated the feasibility of using peat as a filtering medium for the removal of heavy metals and organic compounds from landfill leachate. Adsorption isotherms were established using batch studies, while the migration profiles and breakthrough characteristics were determined from continuous flow studies with peat filter columns. Lead, zinc, calcium, sodium, and organic matter (measured as BOD) were examined. The results, published in the Water Quality Research Journal of Canada, demonstrate the effectiveness of peat to remove heavy metals and other contaminates from landfill leachate.

The natural degradation of organochlorines present in secondary kraft mill effluents has been investigated by scientists at the Pulp and Paper Research Institute of Canada. Samples of effluents in polyethylene bags, which permitted the transmittal of light and gas, were submerged in a lake distant from industrial areas. As described by L. Roy-Arcand and F. Archibald at the CAWQ Eastern Symposium on Water Pollution Research, the bags were submerged at depths of 0.1, 1.1 and 9 metres and periodically sampled to assess their levels of AOX. After 4 months, the mineralization of chlorine in the shallowest sample reached 70 to 85%, with lesser AOX reduction at greater depths.

Because total phosphorus and chlorophyll a concentrations vary seasonally within north-temperate lakes, estimates of lake trophic status are usually based on the results of many sampling visits. McGill University scientists R.L. France and R.H. Peters, together with R.H. Rishikof from Trent University, used data from north-temperate lakes to examine the degree to which single monthly samples for total phosphorus and chlorophyll a represent seasonal means. As described in the Canadian Journal of Fisheries and Aquatic Sciences, the most precise and accurate estimates of the means occur when single visit synoptic surveys were conducted during August to September.

A polymer treatment has been developed in Belgium for removal of colour and toxicity of various wastewaters. D. Gagnon and H.C. Lavallée at the University of Quebec Centre for Research on Pulp and Paper have undertaken to further investigate this technology with a view to optimize and model the process. The results of this research, described at the CAWQ Eastern Symposium on Water Pollution Research, demonstrated its applicability for the treatment of several effluents. The effectiveness of the process depends on a number of factors including the type of wastewater, the nature of the polymer or polymer mixture used, the quantity of polymer added, the pH, and the temperature.

McMaster University scientists studied the effects of a number of variables on the results obtained (kinetics constants for floc agglomeration and breakup) in bench-scale jar tests of turbidity. A two-parameter kinetic model developed by others provided a good fit of the data when they were log-transformed. S.P Szpak, D.R. Woods and K. Bouchard report that the variables having a statistically significant effect were the interaction of clay concentration and flocculation velocity gradient, plus clay type combined with rapid-mix time. The jar and paddle shapes did not have significant effects.

Two nitrification-denitrification systems were used in a University of British Columbia research project to determine the possible inhibitory and/or toxic effects of supplemental chromium and nickel addition to the process in the treatment of a relatively high ammonia, low biodegradable carbon, municipal landfill leachate. The results reported by D.S. Mavinic and coworkers in Water Environment Research indicated that chromium and nickel caused inhibitory effects to the system at soluble concentrations of approximately 0.30 and 0.70 mg/L respectively. Chromium affected both the nitrification and the denitrification process whereas nickel impaired only the nitrification performance.

A paper published in the Canadian Journal of Civil Engineering presents the results of a study by École Polytechnique scientists on the influence of chemical pre-conditioning on gravity thickening and dewatering of biological and chemical sludge (alum dephosphation sludge) from facultative aerated lagoons. Two cationic polymers and two inorganic reagents were studied by M.A. Desjardins and his colleagues. The inorganic reagents did not improve gravity thickening of the sludge while the polymers were more efficient by increasing capture rate and accelerating solids settling. The addition of polymers to sludge to improve thickening does not affect the reconditioning of sludge to be dewatered.

A paper published by J. Burton in Water Science and Technology, describes the application of a river basin management approach, developed by this St. Lawrence Centre scientist, to tropical river basins. A framework for integrated river basin management was designed in consultation with African managers. It begins with an extensive documentation phase to produce an integrated diagnosis of the river basin, moves into a planning phase, and ends with an action and monitoring phase. Integrated river basin management is feasible, but the real challenge lies with the lack of information and the need for a people-oriented approach.

University of British Columbia scientists S.F. Liver and E.R. Hall compared the fate and effects of resin acids in anaerobic and aerobic biological treatment systems under batch reactor test conditions. As described in Water Research, no degradation was observed under anaerobic conditions with a non-acclimated sludge. Under aerobic batch conditions with a non-acclimated activated sludge inoculum, high initial resin acid concentrations were reduced to detection limits in two to three days. The highest specific removal rate measured in this study with non-acclimated aerobic biomass was much higher than comparable values reported by others for acclimated aerobic biomass.

To establish Best Available Technology Economically Achievable (BATEA) in non-urban communities which presently use conventional lagoon technology, B. Evans, R.V. Anderson Associates, and colleagues from the Wastewater Technology Centre, XCG Consultants, and the Ontario Ministry of Environment and Energy evaluated alternatives which can be used to improve lagoon effluent and establish costs. Two existing processes were compared: the Sutton, Ontario plant (nitrifying extended-aeration followed by polishing lagoons, with waste sludge discharged into the lagoons) and the New Hamburg, Ontario plant (aerated or facultative lagoons with lagoon effluents sprayed intermittently over sand filters). Details on the comparisons and the recommended improvements are contained in a paper published in Water Science and Technology.

For more information, contact:
Dr. H.R. Eisenhauer
Canadian Association on Water Quality
Environmental Technology Centre, Environment Canada
3439 River Road South, Gloucester, ON K1A 0H3
Tel: (613) 990-9849, Fax: (613) 990-2855.