GAYAN MANTRA

Chemical Oxygen Demand (COD) – Definition, Principle, Procedure & Importance Chemical Oxygen Demand (COD) is one of the most important parameters used in environmental science and water/wastewater quality analysis. It indicates the amount of oxygen required to chemically oxidize oxidizable substances present in a water sample. What is Chemical Oxygen Demand (COD)? COD is the amount of oxygen required to oxidize organic and certain inorganic substances present in water or wastewater by a strong chemical oxidizing agent. It is generally expressed as: mg/L of O₂ (milligrams of oxygen per litre) A high COD value usually indicates a high concentration of oxidizable pollutants and therefore greater pollution potential. Principle of COD Test In the conventional dichromate method, a known quantity of water sample is heated under acidic conditions with a strong oxidizing agent, usually potassium dichromate (K₂Cr₂O₇). The oxidation is carried out in the presence of sulfuric acid ...

Turbidity and Electrical Conductivity of Water | Complete Environmental Studies Guide Water quality is an important part of environmental science. Two simple but significant parameters used to assess water quality are Turbidity and Electrical Conductivity (EC). They provide useful information about suspended particles, dissolved ions and the overall characteristics of water. 1. Turbidity What is Turbidity? Turbidity is the cloudiness or haziness of water caused by the presence of suspended particles such as: Clay and silt Organic matter Algae and microorganisms Fine soil particles Other suspended materials When light passes through turbid water, these particles scatter the light. The amount of scattered light is related to the turbidity of the water. Measurement of Turbidity Turbidity is commonly measured using a nephelometer/turbidity meter. The result is generally expressed in: NTU – Nephelometric Turbidity Units A standard turbidity suspension is used as a reference for ...