A Stochastic Model to Predict Flow, Nutrient and Temperature Changes in a Sewer under Water Conservation Scenarios

• Published in: Water (Basel) Vol. 12; no. 4; p. 1187
• Main Authors: Bailey, Olivia, Zlatanovic, Ljiljana, van der Hoek, Jan Peter, Kapelan, Zoran, Blokker, Mirjam, Arnot, Tom, Hofman, Jan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-04-2020
• Subjects: Chemical oxygen demand; Drinking water; Greywater; Home appliances; household discharge; Households; Hydrologic cycle; Infrastructure (Economics); Mass flow; Netherlands; Nutrient concentrations; Nutrient flow; Phosphorus; Pollutants; Rain water; Rainwater recovery systems; reduced water consumption; sewer design; Sewer systems; Software; Solid suspensions; Solids flow; Stochastic models; stochastic sewer modelling; Stochasticity; Total suspended solids; United Kingdom; Wastewater; Wastewater discharges; wastewater quality; Water; Water conservation; Water harvesting; Water quality; Water reuse; Water use; United Kingdom; Netherlands; United Kingdom > UK
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w12041187

Reducing water use could impact existing sewer systems but this is not currently well understood. This work describes a new flow and wastewater quality model developed to investigate this impact. SIMDEUM WW® was used to generate stochastic appliance-specific discharge profiles for wastewater flow and concentration, which were fed into InfoWorks® ICM to quantify the impacts within the sewer network. The model was validated using measured field data from a sewer system in Amsterdam serving 418 households. Wastewater concentrations of total suspended solids (TSS), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TPH) were sampled on an hourly basis, for one week. The results obtained showed that the InfoWorks® model predicted the mass flow of pollutants well (R-values 0.69, 0.72 and 0.75 for COD, TKN and TPH respectively) but, due to the current lack of a time-varying solids transport model within InfoWorks®, the prediction for wastewater concentration parameters was less reliable. Still, the model was deemed capable of analysing the effects of three water conservation strategies (greywater reuse, rainwater harvesting and water-saving appliances) on flow, nutrient concentrations, and temperature in sewer networks. Results show through a 62% reduction in sewer flow, COD, TKN and TPH concentrations increased by up to 111%, 84% and 75% respectively, offering more favourable conditions for nutrient recovery.