E2718 V6 PAF GUIDELINE FOR ASSESSMENT OF QUALITY OF DRINKING WATER September 12, 2007 Poverty Alleviation Fund, Nepal (PAF, Nepal) Chakupat, Lalitpur P.O.Box : 9985, Kathmnadu, Nepal Tel. : +977-1-5553671/5553672/5553673 Fax : +977-1-5553674 email : pafnepal@info.com.np web : www.pafnepal.org.np September 12, 2007 86 For assessment and maintaining the Quality of Drinking water PAF will adopt the following guidelines and procedures. 1. Water Quality and Sanitary Condition assessment of water source. Water quality of the source should be assessed along with the surrounding environment to predict extent of possible contamination. The source water quality means and so should be assessed under following grounds. i. Turbidity Clear: When water is transparent and clear. Turbid: When water is not transparent and not clear. ii.Color No Color: When water is transparent and no color. Colored: When water is not transparent and gives color iii.Odour Odourless: When water does not gi ve any odour. Odour: When water gives unacceptable odour. iv. Taste Good: When water is being used for drinking and taste is not objectionable to users. Bad: When taste is not acceptable for drinking. The sanitary condition of source w ould be assessed as per following. Good: When area surrounding the source is clean. Fair: When area surrounding the source is untidy where as there is little chances of contamination due to intrusion of surface water. Bad: When area surrounding the source is not clean, susceptible to animal intrusion, and obvious intrusion of surface water. Also, it is required to carry out bacteriological water quality test and other physical and chemical tests as necessary to ensure that water quality of proposed source i s acceptable for drinking. 2. Water Quality and Sanitary Condition Monitoring. The water quality and sanitary condition monitoring helps to improve source protection methods, intake and other structure designs and to incorporate treatment methods to elimi nate contamination. The water quality and sanitary condition monitoring for a scheme will be done four times in the scheme cycle-during the site survey, during site appraisal, during implementation phase and after implementation phase. The source environmental features are assessed to identify the risk for source pollution. The environmental feature include items such as source catchments characteristics; land -use pattern; existing grazing land and forests; existing irrigation systems and water courses ; and village road/paths and community settlement patterns. Human Settlement Upstream. Human settlement upstream and in the surrounding area influences the quality of water. The use of source upstream has to be investigated. The open excreta disposal system upstream and around the source and possible human intrusion for washing, cattle feeding etc. upstream may cause water pollution. Therefore surveyor should investigate the upstream and surrounding human settlement in the source. If the human settlement exi sts upstream of the source the chance of pollution is high. The conclusion should be made in following areas: · Possible measures to be taken to protect the source from contamination during intake construction. · Possible measures to be taken to protect the i ntake source. · Possible measures to be taken to protect the catchment area of the source. · Acceptability of water from water quality point of view. September 12, 2007 1 3. Possible Measures for Source Protection. Few possible measures to be taken to protect the source from con tamination could be as follows. · Source should be far from human settlement. · The possibility of animal and human intrusion should be discouraged · The catchment area should be announced as protected area and commence tree plantation. · In stead of planting big trees surrounding the source, plantation of shrubs and small trees should be emphasized. · Source should be free from any type of contamination including chemical. If surrounding area is crop field, (i.e., chance of pollution is high), the use of fertilizers surrounding the source should be discouraged. · Spring sources are usually contaminated due to surface run off. This can be prevented by building a diversion drain upstream of the source and side drain as per requirements. The spring source should be cover ed with plastic sheet on top and 30 cm thick earth compaction to prevent from polluted surface run off. In stream catchments various technical alternatives are available for the proper fetching of water. · During monsoon period the stream will have a flood and will bring silts and sands deposits. Hence with proper filter medium (such as sand, gravel and boulder) and with suitable laying of pipe water quality can be improved 4. Water Quality Test. Water Quality Test will be carried out as far as possible an d for that PAF will stick to the National Drinking Water Quality Standard and Guidelines for the Implementation of National Drinking Water Quality Standard 2005. As per National Standard for assessment of Quality of Drinking Water following parameters are to be analyzed for Surface water and Ground water sources. I. For Surface Water sources Type Parameter Unit Maximum Concentration Remarks Limits Turbidity NTU 5 (10) pH - 6.5-8.5* Physical Color TCU 5 (15) Taste & Odor - Should not be objectionable Electrical Conductivity ? s/cm 1500 Iron Mg/L 0.3 (3) Manganese Mg/L 0.2 Chromium Mg/L 0.05 Fluoride Mg/L 0.5 - 1.5 * Ammonia Mg/L 1.5 Chemical Nitrate Mg/L 50 Total Hardness Mg/L 500 Calcium Mg/L 200 Residual Chlorine Mg/ L 0.1 - 0.2 * Only for system using chlorine. Micro E. coli MPN/100 ml 0 Biological Total Coliform MPN/100 ml 0 (95 % in Sample) * These values suggest minimum & maximum limit. September 12, 2007 2 ( ) The value inside bracket is valid if there is no alternate II. For Ground Water sources Type Parameter Unit Maximum Concentration Remarks Limits Turbidity NTU 5 (10) pH - 6.5-8.5* Physical Color TCU 5 (15) Taste & Odor - Should not be objectionable Electrical Conductivity ? s/cm 1500 Iron Mg/L 0.3 (3) Manganese Mg/L 0.2 Arsenic Mg/L 0.05 Fluoride Mg/L 0.5 - 1.5 * Ammonia Mg/L 1.5 Chemical Nitrate Mg/L 50 Total Hardness Mg/L 500 Calcium Mg/L 200 Residual Chlorine Mg/L 0.1 - 0.2 * Only for system using chlorine Micro E. coli MPN/100 ml 0 Biological Total Coliform MPN/100 ml 0 (95 % in Sample) * These values suggest minimum & maximum limit. ( ) The value inside bracket is valid if there is no alternative. September 12, 2007 3