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

Abstract

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.

Hybridised Artificial Neural Network Model with Slime Mould Algorithm: A Novel Methodology for Prediction of Urban Stochastic Water Demand

“…Zubaidi, et al [8] mention that the relation between water demand time series and climatic time series is stochastic. Stochastic models will also offer a better reflection of reality and insight into the system's dynamics [48]. Hence, an empirical mode decomposition (EMD) approach was applied to decompose the original time series of dependent and independent variables into trend, seasonal, stochastic and noise components, and to detect the stochastic component after that.…”

Advances in Modeling and Management of Urban Water Networks

“…Bailey et al [49] present the analysis of the impact of water use reduction on the operation of UDSs. The methodology used for the analysis is made up of two elements, namely SIMDEUM WW®and InfoWorks®ICM.…”

Microbiological Health Risk Assessment of Water Conservation Strategies: A Case Study in Amsterdam

“…One way to make resource recovery more effective is by concentrating the wastewater by using less drinking water. The options are through using water saving appliances and recycling greywater [ 8 ], which may contribute to alleviating the stress of available drinking water sources.…”

“…In addition to greywater reuse, rainwater harvesting is another method that has been proposed to reduce drinking water demand [ 9 , 10 ], although it will not result in a more concentrated wastewater [ 8 ]. Both greywater and rainwater offer an additional source for water usage in households that does not require drinking water quality such as flushing toilets.…”

“…The water conservation scenarios include implementation of water saving appliances such as 1 L flush toilets and water saving showers, and reuse of greywater and rainwater harvesting for toilet flushing and washing machines. Research has been carried out into hydraulics and wastewater composition [ 8 ]. However, the health risks of the implementation of water conservation scenarios have not been assessed yet.…”