People in remote areas are still drinking surface water that may contain certain pollutants include harmful microorganisms and chemical compounds directly without any pretreatment. In this study, we have designed and operated a pilot-scale drinking water treatment unit as part of our aim to find an economic and easily operable technology for providing drinking water to people in those areas. Our small-scale treatment unit contains filtration and disinfection (UV–C irradiation) stages to remove pollutants from source water. The water quality index was determined based on various parameters such as pH, temperature, dissolved oxygen, nitrate, nitrite, ammonium, phosphorus, dissolved organic carbon and bacteria. Water and media samples after DNA extraction were sequenced using Illumina Miseq throughput sequencing for the determination of bacterial community composition. After the raw water treatment, the reduction of bacteria concentration ranged from 1 to 2 log10. The average removal of the turbidity, ammonium, nitrite, phosphorus and dissolved organic carbon reached up to 95.33%, 85.71%, 100%, 28.57%, and 45%, respectively. In conclusion, multiple biological stages in our designed unit showed an improvement of the drinking water quality. The designed drinking treatment unit produces potable water meet standards at a lower cost operation and it can be used in remote areas.
This pilot study proved the effective performance of biofiltration, physical filtration and UV disinfection for removing the pollutants from source water. The biofiltration process showed high removal of turbidity, nitrite and ammonium as well as DOC. The results of physico-chemical and microbiological parameters match the requirements of international standards. Multiple biological stages in our designed unit showed an improvement of the drinking water quality. BAC played an important role in the removal of organic pollutants and turbidity. Nitrospira and Nitrosomonas, which mainly occupy the surface layer of the BAC media in our system, played an important role to remove NH4+-N through the microbial nitrification process. The UV irradiation is recommended for drinking water disinfection because of its power germicidal ability and reduction of disinfectant by-products formation. Our study provides a design for a drinking water treatment system can be used in remote areas at lower operating cost as well as producing potable water meeting international and national criteria.