The grey water treatment plant is designed and developed by Department of Irrigation and Drainage, DBSKKV, Dapoli. It is a combination of natural and locally available material in which physical operations such as inflow, filtration and collection could be performed. The most effective combination of media found after experimentation were 45 cm sand, 45 cm grit, 30 cm brick pieces, 30 cm charcoal and 30 cm gravel, respectively. The hydraulic retention time (HRT) of designed filter was found 24.00 hours at hydraulic loading rate of (HLR) of 3.77 m/day. The filter cross sectional area will increases with the required capacity. The grey water treatment plant was found effective for reduction of turbidity from 80 NTU before filtrationupto 30NTU after filtration. It also reduced effectively the colour and odour of the treated water up to acceptable standards. The BOD, COD, oil and grease, RSC and SAR which are considered to be major parameters influencing water quality were reduced by 82.70, 86.10, 78.78, 69.23, and 21.33 percent respectively. Similarly Sodium, Magnesium, Nitrogen, Potassium, bicarbonate, calcium, TDS, EC and pH were also reduced by 31.42, 33.33, 5.55, 48.76, 44.62, 20.00, 31.19, 26.19 and 0.6 percent respectively. All the chemical parameters of the filtered water were found in permissible range according to irrigation water quality standards. The cost of the construction of the treatment plant is Rs. 31958 per square meter. The filtration capacity per square meter filtration plant is 3770 liter per day. Considering cost of 1 m3 water was Rs. 10, shows the payback period of one square meter grey water treatment plantis 3.0 years. The low construction cost, use of locally available material, less maintains cost and long life increases the importance of the system under scarcity driven situation in rural as well as urban areas.
