Purification of Grey water using the natural method

Abstract

The Water crisis is a major problem now a day. To solve this problem, there are various methods of water conservation such as rainwater harvesting or water reuse. Grey water treatment is also an option for water conservation. Grey water is the untreated household wastewater that has not come into contact with sewage (WHO -ROEM2006). In this study we have used various flocculating agents like alum, PAC, lime, chitosan, alum+ lime, fuller earth, ferric chloride, ferrous sulfate, PAM, Micro+, soya bean, alum+ soya bean etc. and the one thatgave the most significant results were used for further study. Among the flocculating agents used, alum + soybean powder gave promising results. So this flocculating agent and coagulating aid were used for further experiment. We prepared biochar using groundnut husks which is a waste material and activated it using zinc chloride. We prepared a unit which consisted of a column packed with sand, gravel, activated biochar and vetiver roots. We passed the supernatant obtained after flocculation through this unit at flow rate 5L/hr. The effluent water was disinfected using Medichlor. Using this unit the turbidity was decreased to 0.08 NTU, pH was 6.3, TSS was nil, and TDS reduced upto 75%. The microbial load (bacteria, fungi, coliforms, Thermotolerents), MPN test was also found to be negative. The unit which we have prepared was ecofriendly and economically affordable. This treatment system can be used in the new constructions, bungalows, societies etc. The treated water can be used for various purposes such as gardening, car washing, toilet flushing, road construction, irrigation etc.