Abstract
In the scope of this study, a pilot facility for the recycling of laundry effluent was developed and tested. With the aim to enable nearly complete energy and water self-sufficiency, the system is powered by a photovoltaic plant with second-life batteries, treats the wastewater within the unit and constantly reuses the treated wastewater for washing in a closed cycle. The technology for wastewater treatment is based on a low-tech approach consisting of a physical/mechanical pre-treatment and biological treatment in trickling filter columns. The treatment process is operated in batch mode for a capacity of five washing cycles per day. During five weeks of operation water quality, energy consumption and production, water losses and washing performance were monitored. The system recovered 69% of the used water for the washing machine while treating the wastewater to the necessary water quality levels. The average COD removal rate per cycle was 92%. Energy analysis was based on modelled data of the monitored energy consumption. With the current set-up, an internal consumption rate of 80% and self-sufficiency of 30% were modelled. Future developments aim at increasing water and energy self-sufficiency and optimizing the water treatment efficiency.
Highlights
Freshwater is becoming an increasingly scarce resource due to global trends such as urbanization, climate change and population growth [1]
This study examines a pilot low-tech laundry facility on domestic scale where the laundry effluent is treated within the unit and repeatedly reused for washing in a closed cycle
Water quality parameters were monitored in the laundry effluent, after pre-treatment, after the biofilter and in the treated water
Summary
Freshwater is becoming an increasingly scarce resource due to global trends such as urbanization, climate change and population growth [1]. The 2017 United Nations Global Water Report [1] highlights the importance of wastewater reuse as a strategy to address water scarcity. The local treatment and reuse of greywater is experiencing increased popularity because greywater (water from kitchen, bath and washing machine) is only lightly polluted compared to average municipal wastewater [3]. A number of studies have examined local greywater treatment and its reuse potential [4,5,6,7,8,9]. The cascading use of the treated greywater has the potential to reduce freshwater demand and wastewater discharge. Such systems require suitable infrastructure to supply the freshwater and discharge the wastewater
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