Assessment of slow sand filtration system for rural water supply schemes--a case study.

In India, water supply programmes form a part of National Development Plans and are implemented in a phased manner under the Five-Year Plans. A number of departments and ministries of the Central and State Governments have been vested with the responsibility for water supply and sanitation. Due to inherent advantages of slow sand filters over conventional rapid sand filters, the Panchayat Raj Engineering Department (PRED), Government of Andhra Pradesh has designed and constructed a number of slow sand filter plants for rural water supply schemes in the state. At the instance of Netherland Assisted Project (NAP) Office, Hyderabad, NEERI undertook a critical evaluation of the functioning of three slow sand filter plants in Andhra Pradesh and suggested improvements in construction, operation and maintenance (O&M) including a review of design criteria followed by PRED. The paper presents the outcome of these studies along with suggestions needed to bring about improvements in source protection, design, construction, O&M of slow sand filter and training programme to improve the quality of supervision.