Water Analysis

Water Coliforms (Total & E.Coli) This is the most basic test for bacterial contamination of a water supply. Total coliform counts give a general indication of the sanitary condition of a water supply. Therefore, testing for coliform bacteria can be a reasonable indication of whether other pathogenic bacteria are present. E. coli is also an indicator of drinking water quality. E. coli is a sub-group of fecal coliform. Most E. coli bacteria are harmless and have been found in great quantities in the intestines of people and warm blooded animals. However, some strains can cause illness.  Total Bacteria Count Total bacteria count represents the total bacterial load in any given sample. This test is set out to detect all viable microorganisms that could grow aerobically on a plate count agar at appropriate incubation condition (usually 37°c, 48 hours).  pH Testing a water's pH level will indicate the water's acidity or basicity. Testing tap water is important to ensure that it is safe for consumption. pH is a measured on a standard scale from 1 to 14. Values above 7 are considered alkaline and values below 7 are acidic. Tap levels should be between 6.5 and 8.5.  Chloride Chloride should be tested as it can corrode metals and pipes which can then affect the taste of food products; causing nausea and vomiting. Chlorides can also contaminate fresh water streams and lakes, resulting in death for aquatic life. Chloride ions are derived mostly from salt deposits that leech into water. Fresh water has almost no chlorine ions, while saltwater from the ocean has the highest quantity of chlorine ions.  Total Akalinity Total alkalinity is the total concentration of bases in water expressed as parts per million (ppm) or milligrams per liter (mg/L) of calcium carbonate (CO3) and they act as a buffer system that prevents drastic changes in pH.  Total Hardness Hard water is caused by the presence of naturally occurring calcium and magnesium salts. Water with small amounts of these salts is said to be soft, while greater levels of these salts are said to be hard. It is a measure of the quantity of divalent ions.  Calcium Hardness Calcium occurs in water naturally and is an important determination of water hardness. It also functions as a pH stabiliser because of its buffering qualities. Calcium also gives water a better taste.  Magnesium Hardness Magnesium is found in water because it is washed from rocks and subsequently ends up in the water supply. Magnesium has many different purposes, and can get into water in many different ways. Magnesium is just one of the alkali earth metals which is responsible for water hardness.  Nitrate High nitrate levels in water can cause methemoglobinemia, or baby-blue syndrome. You cannot detect nitrate unless chemically analysed as it is a tasteless, colourless and odourless compound.  Nitrite The nitrite ion contains nitrogen in a relatively unstable oxidisation state. Chemical and biological processes can further reduce nitrite to various compounds or oxidise it to nitrate.  Sulfate Sulfates occur naturally in numerous minerals, including barite epsomite and gypsum. These dissolved minerals contribute to the mineral content of many drinking waters.  Ammonia Ammonia gas is extremely soluble in water. It is the natural product of decay of organic nitrogen compounds. Although it is widely used and common in our society, ammonia can be both hazardous and caustic. Ammonia is present in almost all waters, to some degree. In many cases it is deliberately added to chlorinated feedwaters to reduce THM precursors. It is well removed by deionisation processes, but not by softening.  Phosphate Phosphates can play both a positive and negative role in the water and waste water industry: 

• Phosphate is added to boiler and cooling water for corrosion control.
• Phosphate concentration in waste water must be reduced to prevent growth of algae in the receiving body of water.

Chemical Oxygen Demand (COD) COD is the standard method for indirect measurement of the amount of pollution in a sample of water. The result of a chemical oxygen demand test indicates the amount of water-dissolved oxygen (expressed as parts per million or milligrams per liter of water) consumed by the contaminents during two hours of decomposition from a solution of boiling potassium dichromate.  Settleable Solids The settleable solids test is the measurement of the volume of solids in 1 litre of sample that will settle to the bottom of an imhoff cone during a specific time period. The test indicates the volume of solids removed by settling in sedimentation tanks, clarifiers or ponds. The settleable solids test indicates whether the primary and secondary processes are functioning properly.  Total Suspended Solids (TSS) Total suspended solids are solid materials that are suspended in water. These would include silt, plankton and industrial wastes. If a high concentration of suspended solids is found, it can lower the water quality by absorbing light. The water then becomes warmer and lessens the ability of the water to hold oxygen necessary for aquatic life.  Metals Chemistry Alkali metals are very reactive with water. The reactions with water can be violent, with the evolution of hydrogen gas and formation of strongly alkaline solutions.

Viscosity is a measure of fluids resistance to flow. Often defined as an ISO or SAE viscosity grade (such as VG 220 or SAE 15W/40). Typically measured at 40 or 100ºC. Each application will have a viscosity range suited to the task. Too high a viscosity can lead to lubricant starvation, wear in circulating pumps, increased temperatures and reduced efficiency. If viscosity is too low, the components will not be sufficiently separated resulting in excess friction and causing wear on the machinery. A change in viscosity could be due to:

• Contamination with water/fuel/solvents/very small particles
• Oxidation or ageing of the oil
• Incorrect oil
• Mechanical shearing of the oil