A mathematical model for techno-economic evaluation of industrial wastewater sludge to resources

Abstract

Wastewater has typically been regarded as an environmental problem and a source of health hazard. Converting wastewater into value-Added products such as energy production, and various products recovery have become more attractive. Industrial wastewater sludge has become viable resource of many products such as fertilisers, soil conditioner and artificial aggregate or cement-like materials. The objective of this study is to develop a model to select the appropriate wastewater treatment units that could maximise resources recovery via a simple and cost effective technology while complying the environmental discharge limit. A superstructure of potential treatment technologies is proposed in this work. Ideal networks that consist of interconnections between few treatment technologies to remove contaminants and recover valuable products are obtained by maximising the Net Present Value (NPV) for the plant. The model recommends the connection between anaerobic digester (AD), sludge pump (SP) and bio solid utilisation (BS) to reduce the final concentration in the effluent and at the same time generate the maximum amount of bio solid (soil conditioner) for agricultural purposes. Results of the proposed network yields an optimal network selected by the model that gives a positive NPV of USD 4,035, 506.