Abstract

Continuous sensor measurements directly in wastewater are increasingly being used to control wastewater treatment processes. Unisense has developed an online, real-time SulfiLogger sensor for dissolved sulphide measurements, and in this presentation we show how this sensor can be used for optimization of the collection system. We provide examples of how the sulphide sensor can be used to give a full picture of the production of sulphide directly in the wastewater, and we discuss how the sulphide monitoring can enable a minimization of both emissions and chemical use for sulphide mitigation in the sewage system. With proper control of the sulphide production, it is hence possible to save both resources and be environmentally friendly.

Sulphide is a major problem in the utilities’ sewage network, where the toxic gas causes odour problems and can lead to hazardous incidents for sewage workers. Sulphide can furthermore be converted into sulfuric acid in biofilms and cause corrosion on the drainage network, wells, pumping stations and treatment plants. To minimize the amount of sulphide emission from the wastewater, large amounts of chemicals are added to wastewater, which is both costly and environmentally disadvantageous. In the talk we present a new and large demonstration project where Unisense together with Aarhus Vand, Aalborg Forsyning and Thames Water will demonstrate the potential for minimizing chemical dosing and saving on asset management cost by acquiring an overview of the daily and seasonal variations of sulphide load in their collection systems.