Module 3 - Water Quality PDF

MODULE 3 WATER QUALITY Microbiological Tests Source/Mode Population Served Minimum of Supply (no. of persons) Frequency of...

MODULE 3 WATER QUALITY Microbiological Tests Source/Mode Population Served Minimum of Supply (no. of persons) Frequency of It is used to define the characteristics of the water Sampling evaluate its acceptability. Level I 90-150 Once in three (3) months During water sampling, the following should be Level II 600 Once in two (2) included in the assessment report: months Level III less than 5,000 1 sample 1. Weather condition monthly 2. Time of sampling 5,000 - 100,000 1 sample per 3. Flow rate (when possible) 5,000 population 4. Physical appearance (color) monthly more than 100,000 20 samples plus a sample per Water Quality Parameters to be tested 10,000 A. High Priority (Critical) Parameters population 1. Microbiological (Total Coliform, Fecal monthly Coliform) Bottled Once in every Drinking Water two (2) months 2. Arsenic Emergency Before delivery 3. Cadmium Supplies of to users 4. Lead Drinking Water 5. Nitrate Philippine National Standards for Drinking Water 6. Benzene 7. Color Components of Water Quality 8. Turbidity 9. Iron A. Physical Characteristics 10. pH 1. Turbidity – is a measure of the degree of 11. Manganese cloudiness or muddiness of water 12. Chloride due to the presence of silt, clay, 13. Sulfate organic matter or microorganism. 14. Total Dissolved Solids (TDS) High Turbidity can inhibit effects of B. Other Parameters disinfection. 1. Temperature - Maximum level = 5 NTU 2. Biological Oxygen Demand (Nephelometric Turbidity Unit) 3. Ammonia 2. Color – is due to the presence of colored 4. Total Hardness substances in solution such as 5. Chromium vegetable matter and iron salt. 6. Sulfide - Maximum level = 5 TCU (True 7. Dissolved Silica Color Unit) 8. Total Mercury 3. Odor – can be detected by smelling. Pure 9. Pesticides water is odorless. Undesirable odor indicates presence of contaminants. Frequency of Sampling 4. Taste – pure water is tasteless. Undesirable taste indicates presence of Physical and Chemical Test contaminants. Algae, decomposing The minimum frequency for drinking water supply organic matter, dissolved gases and is once a year regardless of service levels. phenolic substance may cause tastes. EC Lazarte 7 B. Chemical Characteristics Methods of Sampling for Drinking-Water Supply 1. Hardness – is due primarily to calcium and Systems magnesium carbonates and bicarbonates (can be removed by Source/Mode Procedure Location of Sample boiling) and calcium and magnesium of Supply of Sampling Sampling Volume Points sulfate and chloride (can be Level I Pump water Sample is Not be removed by chemical precipitation). to waste for taken less than two (2) directly at the 100mL Effects of Hardness in Water minutes to mouth of the a. Magnesium and calcium has a laxative effect. remove pump. water in the b. Lathering of soap is more difficult. water c. Causes scaling in pots and kettles, resulting in column. the reduction of thermal efficiency. Level II Allow water Sample is Not be to waste for taken from the less than at least one farthest 100mL 2. Alkalinity and Acidity (1) minute. standpipe and Acidic water is corrosive to metallic piping at the entering system. point of the pH 7 = normal distribution pH below 7 = acidic system. Level III Remove Sample is Not be pH greater than 7 = alkaline any filters taken from the less than (rubber or source of the 100mL 3. Carbon Dioxide – makes water corrosive due plastic) and distribution to carbonic acid formation. allow water system and to run to taps at 4. Dissolved Oxygen – water devoid of oxygen waste for at strategic has a flat taste. least one sampling point 5. Organic Nitrogen – waste protein products (1) minute. within the from sewage, kitchen wastes and all distribution dead organic matter. network. Bottled Same Sample is Not be 6. Chemical Oxygen Demand – is a measure of Drinking procedure taken from less than the amount of organic content of Water as above for manufacturer's 100mL water. As COD increases, the samples stock and dissolved oxygen decreases because taken from outlets. the bacteria utilize it in the the source. Emergency Sample is Not be oxidation of organic matter. Supplies of taken at less than 7. Iron and Manganese – it can cause staining of Drinking storage 100mL clothing and plumbing fixtures. Water containers and 8. Toxic Substances – arsenic, barium, cadmium, mobile tankers before being hexavalent chromium, cyanide, served to end lead, selenium, silver, and mercury. users. 9. Phenolic Compounds – these cause Philippine National Standards for Drinking Water undesirable taste in water. Preservation and Storage of Samples C. Microbiological Characteristics The bacteriological analysis of water samples Drinking water should be free of pathogeneic collected should be initiated promptly after microorganisms. It should not contain bacteria collection to avoid unpredictable changes. that indicate fecal pollution. EC Lazarte 8 If samples cannot be processed within six (6) hours after collection, the use of ice coolers for storage of water samples during transport to the laboratory is recommended. The time elapsed between collections and processing should in no case exceed 24 hours. EC Lazarte 9