Use of recycled aggregates as filter support and filter media for decentralized water filtration systems

Clean drinking water is crucial for maintaining public health and can be considered a fundamental right of people. Unfortunately, access to potable water is limited for residents of developing and underdeveloped countries, especially in rural communities. Conventional treatment systems for such regions are challenging in terms of installation, operation, and maintenance. An emerging problem of rapid urbanization and proliferating construction industry is huge quantities of Construction and Demolition (C & D) waste, which needs proper reuse and/or disposal. A simultaneous solution to these twin problems is the formulation of a decentralized water filtration system using C & D waste aggregates. In the current study, small-scale (5-lt capacity), decentralized water filtration systems were designed and tested for the treatment of surface water samples. Fresh aggregates were replaced by C & D waste aggregates progressively in the drainage media, support media, and filter media; resulting in a total of seven test filtration devices. The effectiveness of such filters was evaluated for treating river water samples. It was found that the filters prepared with C & D waste aggregates were successful in the removal of turbidity, total solids, and total dissolved solids (TDS). Removal efficiencies up to 98% for turbidity, 86% for total solids, and 61% for the TDS were observed for different combinations of fresh and recycled aggregates in these filters. The results also show that filters made with only recycled aggregates can also yield high levels of contaminant removal and cleaner water. Further, the color and odor of the raw water were also significantly improved. These results show that C & D waste can be successfully incorporated into decentralized water treatment systems and can result in high-quality water through low-cost and low-tech, easy-to-maintain/operate devices.