GAYAN MANTRA

Biochemical Oxygen Demand (BOD) Explained | Definition, Principle, Procedure, Calculation & Importance Introduction Biochemical Oxygen Demand (BOD) is one of the most important parameters used to assess the level of biodegradable organic pollution in water and wastewater. It indicates the amount of dissolved oxygen required by microorganisms to biologically decompose organic matter under aerobic conditions. BOD is widely used in environmental science, wastewater treatment, water-quality monitoring, and pollution assessment. What is BOD? Biochemical Oxygen Demand (BOD) is the amount of dissolved oxygen consumed by microorganisms while decomposing biologically degradable organic matter present in a water sample under aerobic conditions. The standard BOD₅ test measures the oxygen consumed during a 5-day incubation period at 20°C. Definition BOD₅ is the amount of dissolved oxygen consumed by microorganisms during the biological decomposition of biodegradable organic matter ...

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 ...

Most Probable Number (MPN) Test Explained | Complete Environmental Studies Guide ✅ Introduction The Most Probable Number (MPN) Test is a widely used microbiological method for assessing the quality of drinking water. It helps estimate the number of coliform bacteria, which are indicators of fecal contamination. Since contaminated water can spread diseases such as cholera, typhoid, and dysentery, the MPN test plays a vital role in ensuring water safety. What is the MPN Test? The Most Probable Number (MPN) test is a statistical technique used to estimate the concentration of coliform bacteria in a water sample. Instead of counting bacteria directly, it determines the most probable number of microorganisms based on bacterial growth in multiple test tubes. Importance of the MPN Test The MPN test is essential because it: Checks the microbiological quality of drinking water. Detects contamination by coliform bacteria. Helps prevent waterborne diseases. Monitors water used for dom...

Standard Plate Count (SPC) and Soil Profile – Complete Environmental Studies Guide Environmental Studies covers a wide range of topics related to water quality, soil science, and ecosystem health. Two important concepts are Standard Plate Count (SPC) and Soil Profile. These topics are frequently asked in competitive exams and are essential for understanding environmental monitoring and soil characteristics. Standard Plate Count (SPC) What is Standard Plate Count? Standard Plate Count (SPC) is a microbiological method used to estimate the number of aerobic and facultative bacteria present in a water sample. These bacteria can grow under laboratory conditions, usually at 37°C. SPC is widely used to assess the microbial quality of drinking water and wastewater. Purpose of SPC Measures bacterial population in water. Detects excessive microbial contamination. Evaluates the efficiency of water and wastewater treatment plants. Helps ensure water safety for human use. Principle of ...