growers

Dissolved Oxygen (DO) refers to the level of free, non-compound oxygen present in water or other liquids. Oxygen is perhaps the most well-established indicator of water quality. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water.  A dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality. DO can be measured through classical method of azide modification or by membrane-electrode DO meters.

Cyanide is a carbon-nitrogen chemical unit which combines with many organic and inorganic compounds. It is an extremely toxic substance that is produced naturally and artificially. Cyanides are generally not persistent when released to water or soil, and are not likely to accumulate in aquatic life. But high levels of cyanides can cause rapid toxicity among aquatic life. One of the easiest and cheapest method available for the determination of cyanide concentration is the cyanide-selective electrode method.

The presence of dissolved natural organic material, usually from aquatic humic matter, causes water to have color. Certain industries rely to the aesthetic appearance of water suitable for their industrial applications. Color may also affect photosynthetic processes of some underwater plants and algae which may interfere sunlight to pass through. The standard method for color of water is the platinum-cobalt method.

Chlorides are salts resulting from the combination of the gas chlorine with a metal. Chlorine alone as Cl 2 is highly toxic and it is often used as a disinfectant. In combination with a metal such as sodium it becomes essential for life. Small amounts of chlorides are required for normal cell functions in plant and animal life. But excessive amounts of chlorides can also be harmful, such that it can corrode metals and affect the taste of food products. It can also contaminate freshwater streams and lakes. Some aquatic animals cannot survive in high levels of chlorides. By using chloride-selective electrode meters, concentrations of chlorides can already be measured accurately.

Chemical Oxygen Demand (COD) is a measurement of the oxygen required to oxidize soluble and particulate organic matter in water. It is an important water quality parameter that provides an index to assess the effects of discharged wastewater on the receiving environment. Higher COD levels mean a greater amount of oxidizable organic material in the sample, which will reduce dissolved oxygen levels. Thus, it will be harmful to aquatic life. COD can be determined by various method such as closed reflux digestion, by titrimetric method.

Biochemical Oxygen Demand (BOD) is a measurement of the amount of dissolved oxygen (DO) that is used by aerobic microorganisms when decomposing organic matter in water. Like COD, it is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment. The higher the BOD value, the greater the amount of organic matter for oxygen consuming bacteria, and thus higher rate of dissolved oxygen consumption. Depletion of DO causes stress on aquatic organisms, making the environment unsuitable for life. BOD is also used extensively for wastewater treatment and is a common gauge to determine the design of the water treatment facility. The most common technique used for the determination of BOD, is the 5-day incubation BOD test and azide modification method.