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WATER QUALITY: CONTAMINATION AND PROTECTION

WATER QUALITY: CONTAMINATION AND PROTECTION. 1. Water Quality. Microbiological Quality: Presence of organisms that cannot be seen by the naked eye – faecal and total coliforms Physical Quality Affecting taste, odour and appearance. pH, Turbidity etc. Chemical Quality

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WATER QUALITY: CONTAMINATION AND PROTECTION

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  1. WATER QUALITY: CONTAMINATION AND PROTECTION

  2. 1. Water Quality • Microbiological Quality: Presence of organisms that cannot be seen by the naked eye – faecal and total coliforms • Physical Quality Affecting taste, odour and appearance. pH, Turbidity etc. • Chemical Quality Nature and concentration of dissolved substances. E.g salts, organics, etc. Most of these are essential, but in high quantities may cause problems.

  3. 2. Common Water Quality Problems: Surface Water • Faecal Pollution High faecal and total coliform counts –near dense human settlements • Colour and Stability Due to organic acids • Salt Concentrations (TDS) High sulphate and chloride concentrations. Corrosive and distinctly salty

  4. 2. Common Water Quality Problems: Surface Water • Eutrophication High nutrient concentration (nitrogen, phosphate) and high algal concentrations.

  5. 3. Common Water Quality Problems: Groundwater • Salinity Occurs where the predominant geological formations are sedimentary rocks of marine origin. Eg. The Karoo • Fluoride Especially in the coal bearing regions (central and western parts of the country) • Sulphate and Chloride Especially water with high TDS

  6. 3. Common Water Quality Problems: Groundwater • Calcium and Magnessium Especially in dolomitic areas • Iron and Manganese While they commonly occur in high concentrations in groundwater, treatment is easy

  7. 4. Water Pollution • Water Pollution occurs when water is rendered less fit for use as a result of human activities • Waste generated by human activity enters the water environment. Human Activities Waste Streams -Intensive Irrigation/Agri. -Sewage Waste (Domestic/Indust.) -Mining activities -Gray water -Industrial activity -Stormwater -Dense human settlements -Solid waste

  8. 5. Protection of Water • Everyone needs to be involved • National Government must provide a framework (policy) and legislation for protecting our water sources • Provincial and local level management measures and actions must be developed for giving effect to the national water quality management framework and legislation • Business Owners • Industry • Mines • Farmers • Interest Groups • General Public

  9. 6. Water Treatment: Chlorination • Water-borne diseases are spread by pathogens (disease-causing micro-organisms – such as bacteria and viruses) in water • Pathogenic micro-organisms enter water supplies as result of pollution by human and animal wastes. • A lot of bacteria and viruses will remain after the First Barrier and Second Barrier treatment • The final barrier is disinfection – destruction of the harmful micro-organism – though the use of a chemical agent.

  10. 7. Water Treatment: Chlorination • Types of possible disinfectants Chlorine, Ozone, Chlorine Dioxide, Calcium hypochlorite (HTH), Sodium hypochlorite (bleach) and monochloramine • Chlorine is by far the most effective, easy to control, cost effective and used in over 98% of water treatment works worldwide. • Side effects and other issues such formation THM’s have been highlighted – they are all minor and negligible as compared to the benefits of chlorinating water. Eg. Cholera epidemic.

  11. 5. Water Treatment: Fluoridation • Water fluoridation involves addition of predetermined amounts of a fluoride-containing chemical to the water during a water treatment process in order to increase the fluoride concentration to a specific level. • The WRC is currently involved in research to parameters and control that determines safe and effective fluoridation of water • On the other side of the coin is defluoridation where there is also ongoing research to reduce fluoride from waters with high fluoride concentration, though the use of modified locally occurring

  12. 7. Relevant Research • Five main fields of research addressed water quality and related problems • Over 200 projects have been carried out • Over R150 million has been spent • Over 30 patents have been taken • Over 200 reports, workshops, training session. • At least 5 centres of expertise • Over R40 million invested in on going projects • All major water treatment plants are using one or more processes or technology developed through WRC funding

  13. RESEARCH OUTPUTS • Sewage sludge guidelines and addendum to promote safe use of sludge for crop production • Compilation of a guide to assess the magnitude of non-point source pollution • With DWAF – Development of methodology to implement Waste Discharge Charges (Polluter pays principle) • Models to simulate effect of acid mine water on the quality of Witbank Dam • Design of soil covers for coal discard dumps that exclude oxygen formation of acid mine drainage • Use saline mine water to irrigate crops and remove gypsum • Reduced cost to neutralize acid mine water using cheaper agents.

  14. RESEARCH OUTPUTS • Aerobic Digestion (Low cost sanitation) – Almost all waste water treatment plants in SA use this technology • Biosure® Process – Treatment of high sulphate waters (acid mine water) • Environmental technology and Integrated waste water beneficiation – treatment of high volume saline waters • Petro Process • Membrane Technologies

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