Options and limits of quantitative and qualitative online-monitoring of industrial discharges into municipal sewage systems

摘要

In some cities, industrial enterprises’ discharges into municipal sewage systems have a majornimpact on the quantity and quality of inflows to the municipal treatment plants. In many cases,nindustrial discharges stand out on account of the great fluctuations in their volumetric rates ofnflow, pollution loads and temperatures. As a result, these discharges put a great strain on thensewage system, the treatment plant, and ultimately the receiving waters. The enterprisesnconcerned have to pay the treatment plant operators fees based on the load and/or volumendischarged. In most cases, qualitative monitoring operations merely consist of spot checks.nThis means that continuously surveillance is not possible and infringements of the permissiblenlimit values are only discovered by accident. If impermissible discharges are carried out thatnmay be susceptible to causing a treatment plant failure, the rapid initiation of countermeasuresnis not possible. Hence, spectrometer probes and mobile flowmeters were used in order tondetermine volumetric rates of flow, COD concentrations, and ultimately the loads discharged.nThe possibilities for, and limits to, online monitoring as well as shortcomings of spot-checksnare discussed in the course of this paper, which also includes an uncertainty analysis.