News – September 1998

Environmental Compliance & Technologies ’99 Conference & Tradeshow

Environmental Science & Engineering magazine in association with Templegate Information Services Inc., will again be producing the conference and workshop program for “Environmental Compliance & Technologies ’99”. The workshop will also include a table-top trade show. The two day event will be held April 7 – 8, 1999, at the Regal Constellation Hotel, 900 Dixon Road, Toronto (close to Pearson International Airport).

Presenters will be required to prepare written materials and deliver presentations to environmental consultants and managers from across Canada at this two day event.

Preference will be given to those willing to undertake responsibility for organizing half-day sessions likely to be of interest to:

• corporate environmental managers
• engineers and consultants
• municipalities
• environmental and real estate lawyers
• emergency response personnel
• process personnel, etc.

The Conference and workshops will, in addition, feature table-top exhibits and networking opportunities designed to bring suppliers and specifiers together in a professional and stimulating environment. Authors should fax Lawrence Earl: (905) 873-6424.

For information about table-top displays, call Environmental Science & Engineering at: (905) 727-4666 or fax: (905) 841-7271.

Piranhas found in Ontario

A 12-year-old girl landed the larger cousin of a piranha while fishing in a river in Peterborough, Ontario. Meanwhile, Professor’s Lake in Brampton, Ontario was closed for days after a man caught a red bellied piranha there.

The Peterborough girl, Tommi-Jean Russell and her father were not quite sure what she reeled in from the Otonabee River. “It sure had lots of teeth,” said Tommi-Jean, who has been fishing since she was two.

Three biologists from the Ministry of Natural Resources and an exotic-species specialist were unable to identify the fish. Paul Tilley, who owns a fish and aquarium store, immediately recognized the red pacu, a fresh-water tropical fish native to the Amazon Basin.

Tommi-Jean’s catch, which had a large mouth filled with sharp upper teeth, was about 38 centimetres long. Mr. Tilley and ministry officials are convinced the pacu outgrew someone’s aquarium and was dumped into the river.

The fish caught in Professor’s Lake was native to South America, and was likely someone’s unwanted aquarium pet, dumped in the lake sometime this summer.

That single fish cost the City of Brampton more than $5,000 in consulting fees and several thousand dollars in lost revenues from beach admissions and cancelled programs.

Environmental consultants Gartner Lee scoured the 26-hectare lake for four days with nets, traps and snorkels.

The Grand River Conservation Authority spent one day using electrical current to stun fish and bring them to the surface to check for piranhas. No other piranhas were found.

First major drinking water public-private partnership signed by City of Moncton

Moncton, New Brunswick has announced it has awarded Canada’s first major drinking water public-private partnership to Greater Moncton Water Ltd., a New Brunswick incorporated company owned by USF Canada, Inc. (85%), and The Hardman Group Limited (15%).

USF Canada is affiliated with United States Filter Corporation, that manages more than 200 operations and maintenance contracts in North America. The Hardman Group, a privately held company, is Atlantic Canada’s leading independent construction management and real estate development firm.

The 20-year agreement, valued at approximately $85 million (CDN), calls for the financing, design, construction, operation, and maintenance of a 27 million gallons per day (4,250 m3/h) drinking water filtration facility. Upon the facility’s commissioning, Moncton will purchase the plant and Greater Moncton Water Ltd. will enter into a 20-year lease and license agreement with exclusive rights to sell water to the municipality. The article has been abridged.

Easy arsenic removal

A new way to remove arsenic from water has been developed that is both cost-efficient and easily transportable. The process was developed at Environment Canada’s Environmental Technology Centre, in partnership with ZENON Environmental Inc. and the University of Ottawa.

Originally developed to remove arsenic from mining effluents and wastewater where it is effective at over 99 percent, the process can make drinking water safe. This work can provide hope to communities in countries such as Sri Lanka and Bangladesh where arsenic-contaminated water is a major concern.

In Canada, naturally occurring arsenic is found in rocks in Nova Scotia and leaches into water, while in the US some remote communities in New Mexico and Arizona have to bring in drinking water by truck because of arsenic in the local water.

Details: http://www.ec.gc.ca/tips/en

City of Langley leads in water metering

One municipality stands out as a model of water conservation in Greater Vancouver, a region where people drink, spray and flush more per capita than in any other metropolitan area in Canada. A typical Langley city resident uses nearly 50 percent less water than the Greater Vancouver regional average on peak summer days.

For years, homeowners in Langley city paid a flat rate for a certain volume of water before their meters clicked in to charge an additional fee for drawing more. A year ago, the bulk rate was eliminated entirely. The city became the only fully metered municipality in the Greater Vancouver water system.

Langley city taxpayers do benefit as a result of lower water use. It is estimated that Langley has been able to delay some costly local water main expansions.

R&D News

Treatment of Kraft Condensates

University of British Columbia scientists used a feedback-controlled sequencing batch reactor to treat kraft accumulator and evaporator condensates. The control strategy used the level of dissolved oxygen to terminate the oxidation phase and commence the settling phase of each cycle. While treatment rate varied substantially in response to influent variability, the overall level of treatment remained substantially constant with COD removals averaging 88% for the accumulator concentrates, and 64% for the evaporator concentrates. In their paper presented at the 19th biennial conference of the International Association on Water Quality, G.M.D. Milet and S.J.B. Duff reported that over 90% of the initial sulfur compounds were removed.

Resin Acid Degrading Bacteria

University of British Columbia scientists investigated the relationship between the growth rate and ratio of RNA to DNA in four resin acid degrading bacteria isolated from a sequencing batch reactor. Chemical assays, as well as slot blot hybridizations with species-specific oligonucleotide probes, were used by A.F. Murray and W.W. Mohn to quantify the nucleic acids. These slow-growing bacteria have a positive linear correlation between growth rate and RNA/DNA ratio similar to faster-growing bacteria like E. coli. Preliminary experiments reported in Water Science and Technology suggest that hybridization probes can be used to detect growth rate-dependent changes in the RNA/DNA ratio.

Sludge Production Under Aerobic and Anoxic Conditions

J.B. Copp and P.L. Dold presented the results of their research at the WQI ’98 conference which demonstrated a significant difference in biomass yield under anoxic and aerobic conditions using a variety of soluble substrates. The anoxic yield obtained by these McMaster University scientists was only 62% of the corresponding aerobic yield. Batch tests were performed using a seed of either activated sludge from one of two local municipal wastewater treatment facilities or a prepared sample of Pseudomonas denitrificans. Regardless of the test organism, the calculated yields were consistent for each electron acceptor. A novel approach to quantifying the consumption of electron acceptor was employed in these batch tests.

Review of Biodegradability Tests

K.L.E. Kaiser has undertaken a review of the literature in order to propose acceptable testing methods for the measurement of biodegradability of chemicals under both waste treatment and typical environmental conditions. As a result of the survey, published in the Water Quality Research Journal of Canada, this National Water Research Institute scientist recommends a multi-tier biodegradability test system for the protection of the environment and human health. The tiers are comprised of ISO standard tests for rapid biodegradability, for inherent biodegradability under oxidative conditions, and for biodegradability under anaerobic conditions.

Biodegradation of PAHs

J.D. MacRae and K.J. Hall investigated the feasibility of using nitrate as an alternative electron acceptor for PAH-degrading microorganisms in anoxic marine sediment. As described by these University of British Columbia scientists, to delegates attending the 19th biennial conference of the International Association on Water Quality, PAHs could be degraded under denitrifying conditions as long as other nutrients were not limiting. The half-lives of low molecular weight PAHs ranged from 33 to 88 days. The degradation rate of high molecular weight PAHs was slower with half-lives ranging from 143 to 693 days. Nitrate may be applied to sediments in situ or used in bioreactors to reduce bioremediation costs.

Metal Leaching from Sludge

M. Roy (Agriculture et Agroalimentaire Canada) and D. Couillard (INRS-Eau) applied dried urban sewage sludge to a sugar maple and yellow birch forest in Quebec at doses ranging from 200 to 800 kg of available nitrogen per hectare. Metal concentrations were measured in the soil solution at a 30 cm depth during the growing seasons. At the lowest level of sludge treatment, Al and Zn exceeded water quality criteria for the protection of aquatic life while Cu and Pb were below the limits of detection. As concluded in Water Research, the results indicate that there is a potential of metal leaching when sewage sludge is applied at doses of 200 kg available N per ha to soils with pH less than 4.5.

Bioremediation of Contaminated Soil

P.Y. Yeung, R.L. Johnson and J.G. Xu studied the effects of temperature and forced aeration on the biodegradation rate in soil contaminated with crude oil from a pipeline break using a field operated bioreactor. As described in the Journal of Environmental Quality, the soil was aggregated, amended with nitrogen and phosphorus fertilizers and packed 15 cm deep in the bioreactor. Both heating and, to a lesser extent, forced aeration significantly increased the hydrocarbon biodegradation rate. The half-lives of the hydrocarbons remaining in the bioreactor, measured by these Alberta Research Council scientists, were 105 days for the heat treatment alone, 182 days for forced aeration, and 248 days for the control.

UV Disinfection of Wastewater

McGill University scientists R. Gehr and H. Wright conducted collimated beam and pilot tests using low or medium pressure UV lamps to assess the disinfection performance of a municipal wastewater which had been pretreated by ferric chloride coagulation followed by sedimentation. The feed to the UV systems contained high levels of Fe. As described to delegates attending WQI ’98, the collimated beam tests indicated that the target level of 2,500 coliform units per 100 ml often could not be reached. The pilot tests revealed significant fouling after only a few hours.

PCBs in the St. Lawrence River

University of Ottawa scientists M.R. Richard and F.R. Pick, and M.E. Fox from the National Water Research Institute, examined PCB concentration and congener composition in sediments and in macrophytes in the St. Lawrence River downstream from Cornwall. As described in the Journal of Great Lakes Research, total PCBs in the macrophytes ranged from 37 to 585 ng/g dry weight, with biota to sediment accumulation factors ranging from 0.3 to 10. Congener specific analysis showed that congener patterns shifted between plants and sediments, macrophytes tending to have higher levels of tetrachlorobiphenyl congeners. The high biomass of macrophytes within the river represents an important reserve of PCBs which may be transferred to food webs.

Suspended Biomass in Distribution Systems

M. Prévost and colleagues from École Polytechnique and the City of Laval investigated the presence of suspended bacterial biomass in two full-scale drinking water distribution systems. The results reported in Water Research show that biomass and bacterial production are lower in the distribution system fed by the treatment plant with the lower biodegradable dissolved organic carbon concentration in the plant effluent. The results also suggest that heterotrophic plate counts are not a good indicator of bacterial regrowth in distribution systems. Statistical analysis demonstrated that the treatment type and cumulative surface to volume ratio are the significant factors affecting regrowth in the distribution systems studied in warm waters.

Effect of Nutrient Removal on COD

A number of studies have identified the possible phenomenon of COD “loss” in nutrient removal activated sludge systems. One potential cause for the calculated loss is the mathematical assumption made with regard to nitrate reduction in denitrification. J.B. Copp and P.L. Dold undertook batch denitrification tests to examine the phenomenon. As described in Water Research, these McMaster University scientists were able to confirm that, in fact, no COD was “lost” in these dominant denitrifier experiments with a simple soluble substrate.

Phosphorus Removal by Intermittent Aeration

D.S. Mavinic and colleagues at the University of British Columbia undertook a bench-scale continuous-flow study to investigate the factors affecting phosphorus removal in a two-stage intermittent aeration process. The two-stage process consisted of an anaerobic zone and an intermittently aerated completely mixed tank in which the intermittent aeration was controlled by the absolute oxidation-reduction potential. The results were presented by H.W. Zhao in a paper at WQI ’98 conference in Vancouver. The degree of phosphorus removal in the process depended mainly on the presence of acetate in the aerobic zone. The average ORP control level also affected phosphorus removal at relatively low external acetate dosages.

Bioaccumulation Methods

B.K. Burnison has evaluated methods recommended by OECD, ASTM and USEPA for the determination of chemical bioconcentration. As concluded by this National Water Research Institute scientist in the Water Quality Research Journal of Canada, recently finalized USEPA methods are recommended for the determination of the bioaccumulation factor (BAF) and bioconcentration factor (BCF) in fish. The slow-stir method is considered the most accurate for direct determination of the n-octanol-water partition coefficient (KOW), but computer estimations of KOW can be used when a direct measurement is unavailable. Recent bilinear equations have been derived to predict BCF values from KOW.

Determination of Past Aquatic Habitat

Environmental quality measurements for the St. Lawrence River are relatively scarce for periods prior to the 1970s, yet long-term data are often required for effective ecosystem management. In a study published in the Journal of Great Lakes Research, Queens University scientists E.D. Reavie and J.P. Smol develop a paleolimnological transfer function to provide information on past aquatic habitat. Using diatom algae collected from three dominant habitats in the river (rocks, macrophytes, filamentous algae), habitat preferences of the diatom were identified. Inference models were then developed to reconstruct past habitat conditions from fossil diatom assemblages using logistic statistical techniques.

Alkyl Phenols in Sewage Wastes

Samples of raw sewage, final effluent and sludge were collected from 16 wastewater treatment plants across Canada. D.T. Bennie and colleagues from the National Water Research Institute analysed these for 4-nonylphenol, nonylphenol ethoxylate, nonylphenol diethoxylate, and 4-tert-octylphenol. As reported in the Water Quality Research Journal of Canada, measurable quantities of these chemicals were found in almost all the raw sewage and sludge samples. Of the final effluents, 60% contained detectable amounts of 4-tert-octylphenol at concentrations up to 0.37 µg/L. Almost all the final effluents had detectable levels of the remaining alkyl phenols at concentrations ranging up to 26 µg/L.

Monitoring Biofilter Biomass

Y. Le Bihan and P. Lessard used enzymatic assays to monitor the biomass of a biofilter working under different operational conditions. In backwash waters used as biomass source, these Laval University scientists found that many enzymes, as well as dehydrogenase expressed in volumetric units, seem to correlate with volatile suspended solids (VSS) and with volumetric feeding mass. As described in Water Science and Technology, only the specific concentration of ß-Glucuronide correlates negatively with this volumetric feeding mass. The influent temperature simultaneously affects the specific concentration of ß-Glucuronide, the head loss behaviour and the total sugars/VSS ratio.

Anaerobic Degradation of Acetic Acid

University of Ottawa scientists Z. Ning, L. Fernandes and K.J. Kennedy investigated the anaerobic degradation kinetics of acetic acid in the presence of 2,4-dichlorophenol (2,4-DCP) using 2,4-DCP acclimated anaerobic granules. As described at the 19th biennial conference of the International Association on Water Quality in Vancouver, the effect of acetic acid on 2,4-DCP dechlorination was minimal. On the basis of model discrimination, the degradation kinetics of acetic acid were found to follow non-competitive inhibition with 2,4-DCP as an inhibitor.

Micro-scale Assays for Sediment Toxicity

C. Côté and colleagues applied a battery of 18 micro-scale assays and two benthic assays to assess test and endpoint performance in detecting the toxic potential of 15 freshwater sediment samples collected in the St. Lawrence River – Great Lakes systems. The two benthic assays and seven micro-scale assays successfully passed a double-tiered assessment protocol devised by these scientists from BEAK International Inc., Centre Saint-Laurent, and Eco-Innovation Technologique. As reported in the Water Quality Research Journal of Canada, micro-scale tests whose results most closely matched those of the benthic tests for appraisal of whole sediment toxicity, sediment contamination level and benthic community structure index included three bacterial assays, one algal assay, and three microinvertebrate assays.

Sorption of Organics

In a joint Ryerson Polytechnic University – National Water Research Institute study, S.N. Liss and colleagues studied the relationships between structure of minimally perturbed activated sludge flocs and the sorption of organic contaminants. The results, published in Water Science and Technology, show significant removal of selected halogenated hydrocarbons and polycyclic aromatic hydrocarbons by biosorption to activated sludge flocs. The addition of chromium (CrIII) metal ions to the biomass caused observable changes in the floc structure. At low concentrations, chromium caused an increase in the sorption suggesting that changes in the floc structure can be induced which have an impact on the sorption of pollutants to the flocs.