Environmental accounting--a decision support tool in WWTP operation and management.

The various emissions to water, air and soil from the municipal wastewater treatment plant of Avedore Wastewater Service Company are accounted for and quantified in terms of the environmental impacts to which they contribute: global warming, acidification, eutrophication, space demand for controlled deposition of residues, as well as persistent toxicity, human toxicity and eco-toxicity. The impacts are expressed on the same scale, namely as fraction of the total per capita loads in a national scenario 1990, also called the person equivalent or PE1990. This provides a compact and informative overview of the environmental impacts and allows for a holistic prioritisation in the operation and management of the plant. The accounting shows that the resulting emissions per person in the catchment area of the plant correspond to 0.5-5.0% of the average Danish PE1990 for the impacts in question.