Evaluation of custom‐made and commercial greywater treatment systems: a case study from Oman

This paper reports a study to evaluate two types of greywater treatment systems; commercial and custom‐made. Commercial greywater treatment systems are expensive for small quantities. Therefore, a cost‐effective, low maintenance treatment system was designed to collect, treat and re‐use ablution water from small‐ to medium‐sizes mosques. The system included a sand trap, an ablution water collection tank, a filtration unit, chlorination chute, and treated water collection tank. Treatment and re‐use was automated using submersible pumps and timers. The study revealed that both the commercial and custom‐made systems were capable of treating greywater to satisfy relevant government regulations in Oman. The financial analysis showed that the internal rate of return (IRR) for custom‐made and the commercial systems for the mosques were 14.9% and 19.06% respectively. IRR for the commercial system at private house was −1.44%. Costs of the systems and the amount of greywater treated were the main factors affecting the IRR.