Environmental impacts have been attributed to the discharge of treated sewage effluents to receiving freshwater, estuarine and marine environments.
Domestic sewage treated to secondary or tertiary level generally produces an effluent that has low toxicity but, after dilution in receiving waters, has the potential to stimulate growth within biological receptor populations by nutrient enrichment. On the other hand, domestic sewage having an industrial waste component produces an effluent after secondary or tertiary treatment, similar to the above, but tends to contain low residual concentrations of persistent contaminants that may accumulate in the receiving water environment.
EnviroGulf Consulting (EGC) undertakes assignments to conduct environmental impact assessments of sewage effluents in receiving water ecosystems.
EGC undertakes field surveys to assess receiving water quality and aquatic biological effects of sewage effluent and storm water overflows. Internationally-registered laboratories are subcontracted by EGC to conduct the following types of analyses:
- Dissolved oxygen, BOD, COD, TOC, DOC, pH etc.
- Major cations and anions.
- Nutrients (NH3-N, NO3-N, NO2-N, PO4-P, SRP etc.)
- Trace metals.
- Dioxins and furans.
- Hexane extractable matter (HEM).
- Polychlorinated biphenyls (PCB's).
- Organochlorine Pesticides.
- total coliforms.
- faecal coliforms.
- Escherichia coli.
- Clostridium perfringens.
- general plate counts.
EGC offers the following services to clients:
- Critical review of existing literature, reports and databases on environmental contamination by sewage effluent.
- Design, implementation and execution of water quality surveys to define the physico-chemical effects of sewage effluent disposal to inland and marine waters.
- Design, implementation and execution of biological surveys to describe the physico-chemical impact of sewage effluent on receiving water communities.
- Physico-chemical and micro-biological profiles of sewage effluents and receiving water quality.
- Assessment of the potential for eutrophication and productivity changes due to nutrient enrichment in receiving freshwater, estuarine and marine ecosystems.
- Development of statistically designed sampling and monitoring programs.
- Assessment of the environmental behaviour, fate and biological impact of contaminants and persistent chemicals discharged in sewage effluents.
- Contaminant residue analyses of waters, sediments and biota.
- Environmental effects of land treatment of sewage sludge and application of treated effluent for watering/irrigation.
- Preparation of technical reports on the above.
The Principal of EGC has experience in the physico-chemical, biological and microbiological assessment of waters containing sewage effluents.
- Designed and established research facilities to undertake 5 years of basic research on the effects of an oxidised, well-nitrified sewage effluent on the water quality and biology of artificial stream mesocosms (Applied Hydrobiology Research Station, Staffordshire, UK).
- Report on the effects of an oxidised sewage effluent on the growth, productivity and tissue metal contamination of captive fish, benthic algae, bryophytes and macroinvertebrate populations (Applied Hydrobiology Research Station, Staffordshire, UK).
- Assessment of the effects of treated sewage effluent on the water quality and biological communities of the River North Esk (to Forth Valley River Purification Board).
- Microbiological assessment of water quality in the Rivers Cole and Tame, West Midlands (to University of Aston in Birmingham).
- Assessment of the marine physico-chemical and biological effects of a treated sewage effluent discharge for the Misima Gold Project (with NSR for Placer-Pacific).
- Assessment of the marine physico-chemical and biological effects of a treated sewage effluent discharge for the Lihir Gold Project (with NSR for Kennecott-Niugini Mining Joint Venture).
- Assessment of the effects of sewage effluent disposal to the Noosa River estuary (with NSR for Maunsell & Partners).