October 2013 Manual Introduction to Drinking Water Quality Testing 424 Aviation Road NE Calgary, Alberta, T2E 8H6, Canada Phone: + 1 (403) 243-3285, Fax: + 1 (403) 243-6199 E-mail: [email protected], Website: www.cawst.org CAWST, the Centre for Affordable Water and Sanitation Technology, is a nonprofit organization that provides training and consulting to organizations working directly with populations in developing countries who lack access to clean water and basic sanitation. achieved, in part, by developing and freely distributing education materials with the intent of increasing the availability of information to those who need it most. This document is open content and licensed under the Creative Commons Attribution Works 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0 or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California 94105, USA. 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Introduction to Drinking Water Quality Testing Manual Table of Contents Section 1: Overview of Drinking Water Quality Testing Section 2: Planning for Drinking Water Quality Testing Section 3: Sanitary Inspections Section 4: Water Sampling and Quality Control Section 5: Testing for Physical Parameters Section 6: Testing for Chemical Parameters Section 7: Testing for Microbiological Parameters Section 8: Interpreting Test Results Appendix 1: Sanitary Inspection Forms Appendix 2: Product Sheets Appendix 3: Chemical Fact Sheets Appendix 4: WHO Guidelines for Chemicals and Health Effects Appendix 5: Culture Media Appendix 6: Data Recording Forms Appendix 7: Water Quality Testing Report Appendix 8: International Travel with Test Equipment and Materials Appendix 9: Country Fact Sheets i Introduction to Drinking Water Quality Testing Manual ii Introduction to Drinking Water Quality Testing Manual Acronyms AAS atomic absorption spectrometer BSF biosand filter CAWST Centre for Affordable Water and Sanitation Technology CFU colony forming units DWQT drinking water quality testing EC electrical conductivity ENPHO Environment and Public Health Organization FC fecal coliform FRC free residual chlorine FTU Formazin turbidity units H2S hydrogen sulphide HWT household water treatment HWTS household water treatment and safe storage ICP inductively coupled plasma L litre m metre MCL maximum contaminant level MF membrane filtration mg milligram mL millilitre MLSB membrane lauryl sulphate broth mm millimetre MPN most probable number ND no date, not detected NGO nongovernmental organization NTU nephelometric turbidity units P-A presence-absence PPB parts per billion PPM parts per million SMCL secondary maximum contaminant level SODIS solar disinfection iii Introduction to Drinking Water Quality Testing Manual SOP standard operation procedure TC total coliforms TCU true colour units TDI tolerable daily intake TDS total dissolved solids TNTC too numerous to count TTC thermotolerant coliform µg microgram µm micrometer UN United Nations UNDP United Nations Development Programs UNICEF US EPA United States Environmental Protection Agency WHO World Health Organization Measurement Conversions Length or Distance Volume Weight 1 foot = 0.30 metres 1 gallon = 3.78 L 1 kg = 1,000 g 1 m = 3.28 feet 1 L = 0.26 gallons 1 g = 0.001 kg 1 inch = 25.4 mm 1 L = 33.8 fluid oz (US) 1 g = 1,000 mg 1 inch = 2.54 cm 1 L = 1,000 mL 1 mg = 0.001 g 1 cm = 0.39 inches 1 mL = 0.001 L 1 mg = 1,000 µg 1 cm = 10 mm 1 µg = 0.001 mg 1 mm = 0.1 cm 1 mm = 1,000 µm 1 µm = 0.001 mm Concentration 1 ppm = 1 mg/L = 1/1 million = 0.000001 1/1 billion = 0.000000001 To convert ppb to ppm divide by 1,000 To convert ppm to ppb multiply by 1,000 To convert µg/L to mg/L divide by 1,000 To convert mg/L to µg/L multiply by 1,000 iv Introduction to Drinking Water Quality Testing Manual Glossary Accuracy How close a measured value is to the actual (true) value. Adsorption When a contaminant attaches or sticks to the surface of a solid, such as a grain of sand. Agar A semi-solid gel with nutrients used to grow bacteria. Aseptic technique Preventing contact with microorganisms. Bacteria Single-celled microorganisms, typically a few micrometres (µm) in length. They can live in water, soil, in animals and on plants. Bacteria are usually too small to see with the human eye. Some, but not all, bacteria can make you sick. Blue-baby syndrome An illness most common in young infants that can be caused by drinking high amounts of nitrate, which results in the blood losing its ability to effectively carry oxygen. Boiling Disinfection of water by heating it until it bubbles. To kill all the pathogens in the water, you must boil (lots of bubbles covering the whole surface of the water) for at least 1 full minute. Broth A liquid with nutrients used to grow bacteria. Carcinogenic A chemical that can cause cancer. Chronic Continuing or occurring again and again for a long time. Opposite of acute. Coliform A group of generally harmless bacteria which may come from feces or the natural environment. Colony (bacterial) A group of bacteria growing on the surface of culture media. A colony usually starts growing from a single bacteria and appears as a circular dot on the culture media. Community water The management and administration of the water supply usually supply handled by the local community. Community water supplies may include simple piped water systems, boreholes with mechanized or hand pumps, dug wells and protected springs. Concentration The ratio of the quantity of any substance present in a sample of given volume or a given weight compared to the volume or weight of the sample (e.g., mg/L, µg/L, ppm, ppb). Consumable Items that are used once or for a limited time and then disposed. Must be purchased on a regular basis for water quality testing (e.g., v Introduction to Drinking Water Quality Testing Manual reagents, filter paper, absorbent pads). Contamination Pollution of water due to human or natural causes. Culture media Combination of nutrients and reagents used to grow bacteria. Broths and agars are two examples of culture media. Deionized water Also known as demineralized water. Water that has had its minerals removed, such as sodium, calcium, iron, copper, chloride and sulfate. Deionization is a chemical process that removes the minerals from water. However, deionization does not significantly remove pathogens (e.g., viruses, bacteria). Disinfection A process that removes, deactivates, or kills pathogens in water. It is the last step of the household water treatment process, after sedimentation and filtration. Disinfection is less lethal than sterilization because it destroys most pathogens, but not necessarily all of them (e.g., bacterial spores). Distilled water Water that has many of its chemical, physical and microbiological impurities (e.g., minerals, turbidity, pathogens) removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container, thus leaving all of the impurities behind. Drinking water quality The chemical, physical, and microbiological parameters of drinking water. Effluent A discharge of liquid waste or sewage. Equipment The permanent hardware that is usually only purchased one time for water quality testing (e.g., incubator, scale, digital meters). Fecal bacteria Bacteria found in the feces of humans or warm-blooded animals. Their presence indicates fecal contamination of water and the possible presence of pathogens. Filter paper A porous paper used in membrane filtration through which the water sample is filtered and which retains the bacteria. Pore sizes for fecal bacteria are between 0.45 and 0.7 µm. Flow rate The speed at which water flows through a filter. The flow rate can be measured as the amount of time it takes to fill a container of water - often a 1 litre container. For the biosand filter, the flow rate should be measured when the reservoir is completely full of water. Fresh water Water that contains less than 1,000 mg/L of dissolved solids such as salt. Guideline A recommended limit that should not be exceeded. vi Introduction to Drinking Water Quality Testing Manual Helminth Worm or fluke. They can live in water, soil, in animals and on plants. Helminths can be very small (hard to see with the human eye), or large (up to meters in length!). They are parasites – they can live inside you and take nourishment (food) from you, making you sick. Implementation The process of carrying out a plan. The implementation phase of a project happens after the project plan has been created. Incidence Incidence is the rate of new (or newly diagnosed) cases of the disease. It is generally reported as the number of new cases occurring within a period of time (e.g., per month, per year). It is more meaningful when the incidence rate is reported as a fraction of the population at risk of developing the disease (e.g., per 100,000 or per million population).