Effluent treatment plants such as the Gold Bar Wastewater Treatment Plant in Edmonton, Alberta, from which the effluent stream can be seen above as a dark color in the North Saskatchewan River water, need to deal with an expanding range of compounds. Photo: City of Edmonton, Alberta, Canada
Instead of testing for the presence of a limited range of compounds, it's more effective to ask what effect, if any, the effluent has on organisms in the receiving environment. Effects-based testing removes the guesswork and focuses on what really matters: the impact on the living creatures exposed to the substances.Test Process
Effects-based testing involves exposing organisms to effluent, measuring the effect of that exposure, performing fractionation, and retesting the fractions.
The fractionation procedure uses conventional wastewater treatment technologies such as aeration, filtration, manipulation of pH, and solubility in water. One effluent sample is turned into 24 fractions to isolate compounds based on their physical/chemical properties. Then all fractions are tested, and the fractions with the greatest effect are analyzed.
The effects of the different fractions are totalled and compared to those in the unfractionated effluent to determine recovery and identify potential synergistic and other interactive effects. Once the substance has been identified, and if it's commercially available, it can be added back into the effluent as a final confirmatory step.
Estrogenic compounds are an example of the utility of an effects-based investigation. We know these compounds turn male fish into females, so the measurable effects include changes to the appearance of the fish and production of an egg yolk protein in the blood (vitellogenin). If these effects aren't found, it can be deduced that no effective levels of EDCs are present in the effluent stream.
If the effects are found, the next stage is to corroborate them with faster, inexpensive tests that require less volume, such as the yeast assay. The sample is subjected to a routine fractionation procedure to isolate the responsible estrogens from compounds, including other estrogens, that aren't causing the effect. Once isolated, the compounds are more easily identified and managed.
The cost of conducting this type of testing to confirm the presence of EDCs in an effluent, including the initial confirmatory test, fractionation, retesting of fraction, chemical analyses, and reporting typically ranges from $15,000 to $25,000. The lower cost is for identifying conventional contaminants; the higher cost covers using mass spectra to identify chemicals not previously isolated and recognized.
For wastewater managers, the return on investment comes in peace of mind, pre-emptive compliance with pending and future regulations, and potential savings from not having to commission a lab to identify unknown compounds.
— Stephen Goudey and Laura Tipple are CEO and manager of business development and communications, respectively, for HydroQual Laboratories Ltd., Calgary, Canada.Articles & Extras
- Sidebar: To Screen or Not to Screen?: Testing breaks new ground but raises new questions
- Sidebar: From Micro to Nano: Even as we contend with micro constituents, the byproducts of nanotechnology are invading our effluent
- Making Water Work: The main page for WaterWorks, an in-depth look at how municipalities are changing the way wastewater and stormwater is being treated to avoid water pollution
- Processing Success: An Oregon city relies on sequencing batch reactor technology to clean up wastewater discharging into the economically vital Columbia River
- Pipe-within-a-Pipe: A Northern Ohio wastewater utility shaves $1 million from its stormwater compliance project with a dual-material design
- Fish Stories: Effects-based testing goes directly to the source to discover the environmental impact of wastewater contaminants on living organisms
- New Products: Water, wastewater and stormwater products
To see Web-exclusive material for the "PW Solutions: Water Works" series visit the Article Links page.