Identification of Contaminants Present in Rainwater Collected from Ground Pit and its Removal

Abstract

The need to use rainwater has become increasingly significant due to water scarcity, urbanization and rapid population growth, climate change, environmental sustainability, improved water quality, resilience and independence. Generally, rainwater is collected from rooftop which is not sufficient to meet the demand in water scarcity areas. In this research, the rainwater was collected from the pit dug on the open ground from two different locations. Odor, color, conductivity, total dissolved solids (TDS), turbidity, hardness, pH value and dissolved oxygen tests were conducted on the collected rainwater samples to identify the contaminants after settlement of suspended particles using plain sedimentation technique. Coagulation-flocculation, Mechanical filtration, Granular activated carbon and Powdered activated carbon filtration, Reverse Osmosis and jute rope method was used to treat the rainwater. Two methods i.e., chlorination and UV Irradiation were used to disinfect the treated rainwater. It was found that rainwater collected from two different locations have very low TDS at the time of collection and it goes on increasing with time when left undisturbed. In this research, comparison of different methods of treatment of rainwater was conducted considering quality, feasibility and cost effectiveness of the tests. Pros and cons of each method were analysed to determine the most suitable approach for treating rainwater in water-scarce areas. The study revealed that while reverse osmosis and activated carbon filtration achieved superior water quality, they were less cost-effective compared to simpler methods like the jute rope technique, which showed promise for rural and low-income settings. Chlorination proved highly effective in maintaining microbial safety, while UV irradiation offered a chemical-free alternative with minimal operational complexity. This comprehensive evaluation provides a roadmap for selecting appropriate rainwater treatment methods tailored to specific regional needs, balancing quality, cost, and feasibility to support sustainable water management practices.