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Dispersion of the Stratford sewage treatment plant effluent into the Avon River

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dc.contributor.author Bacchus, Alan
dc.coverage.spatial Avon River Basin
dc.coverage.spatial Stratford
dc.coverage.spatial Ontario
dc.date.accessioned 2018-12-05T13:56:19Z
dc.date.available 2018-12-05T13:56:19Z
dc.date.copyright 1982
dc.date.created 1982-08
dc.identifier.uri http://hdl.handle.net/10214/14563
dc.description.abstract As part of the Stratford-Avon River Environmental Management Project, the Water Resources Branch of the Ontario Ministry of the Environment investigated the possibility of creating a shore-attached effluent plume and mixing zone boundaries in the Avon River below the Stratford Water Pollution Control Plant (WPCP). In a survey conducted on June 18, 1980, Rhodamine-WT dye analyzed with standard fluorometric techniques was used as a tracer to determine the extent of the WPCP mixing zone. Data from the survey were used to calibrate the mixing zone model MIXAPPLN. MIXAPPLN was then used to make predictions of allowable total residual chlorine (TRC) and ammonia concentrations in WPCP effluent under various effluent and streamflow conditions. Survey results indicate that at 247 m downstream of the WPCP outfall, the effluent has completed crossed the stream (however, concentrations at that point are not uniform across the stream). These observations suggest that it may be necessary to realign the outfall position and perhaps channelize the river bed downstream of the outfall in order to create a shore-attached effluent plume and a zone of passage for aquatic fauna. Results of subsequent computer modelling indicate that allowable effluent concentrations depend on the size of the limited use zone For example, a limited use zone of 40% of the river width can be achieved with TRC concentrations in the effluent of 80 ?g/L under the most favourable conditions, and 13 ?g/L under the worst, to meet Provincial Water Quality Objectives (PWQO ). By contrast, to achieve a 20% limited use zone, effluent requirements are much more stringent. Under the most favourable conditions, only 6 ?g/L TRC is allowable in the effluent, and this falls to 4 ?g/L under the worst conditions. For ammonia, similar patterns are observed. To achieve a 40% limited use zone under the most favourable conditions, the maximum allowable total ammonia concentration in the effluent is 4 mg/L. Under more typical summer conditions of average flow, high temperature and high pH, effluent concentrations would have to be restricted to less than 1.0 mg/L. For a 20% limited use zone, the effluent requirements for total ammonia are still more stringent, as they were for TRC. Under the most favourable conditions, the maximum allowable total ammonia concentration in the effluent is 2 mg/L. Under more typical summer conditions, the allowable effluent concentration fails to 0.39 mg/L. Because these levels are lower than are usually observed in the WPCP effluent modifications to the WPCP processes or structure (e.g. dechlorination, improved nitrification) should be evaluated in order to assess the feasibility and cost of meeting the provincial water quality objectives for chlorine and ammonia under summer conditions.
dc.description.sponsorship Ontario Ministry of the Environment
dc.format pdf
dc.language.iso en
dc.publisher Queen's Printer for Ontario
dc.relation.ispartofseries Technical report S-8, Stream Management Sub-Committee, SAREMP
dc.rights Queen's Printer for Ontario, Crown Copyright, Non-Commercial Use Permitted
dc.rights.uri https://www.ontario.ca/page/copyright-information-c-queens-printer-ontario
dc.subject river
dc.subject water quality
dc.subject sewage treatment
dc.subject effluent
dc.subject control measures
dc.subject water pollution control plant
dc.subject mixing zone
dc.title Dispersion of the Stratford sewage treatment plant effluent into the Avon River
dc.type Technical report
dc.rights.holder Queen's Printer for Ontario
dc.contributor.affiliation Water Resources Branch, Ontario Ministry of the Environment


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