What are the Four Fundamental Methods for Testing Wastewater?
Wastewater testing is essential for sustaining human health, the environment, and agriculture. As the industrialisation of society continues, the release of untreated or under-treated wastewater into the environment may be very dangerous for soil, crops, water bodies, and aquatic life. Therefore, wastewater should be tested and analysed strictly. In this blog, we explore the wastewater testing procedures used in water testing labs in Chennai that are crucial to water quality measurement.
Wastewater Definition & Indicators
Wastewater is described as water that has been negatively impacted in quality by human activities. It is mainly a result of domestic, industrial, commercial or agricultural activities. This water is also usually laden with pollutants, such as chemicals, biological waste and heavy metals.
To measure the degree of pollution, specialists check essential indicators such as:
- Biochemical Oxygen Demand (BOD)
- Chemical Oxygen Demand (COD)
- Total Suspended Solids (TSS)
The levels of nutrients such as phosphorus and nitrogen compounds determine the level of pollution in the wastewater. The standard practices used in wastewater testing are helpful in identifying such pollutants and in determining compliance with the local standards of environmental discharge before releasing into natural water bodies.
Determination of Total Ammonia Nitrogen (TAN)
One fundamental parameter in wastewater testing is the Total Ammonia Nitrogen (TAN), which measures the combined amount of un-ionised ammonia (NH₃) and the ionised form, ammonium (NH₄⁺). It is one of the most important indicators of water pollution, especially by sewage, animal wastes and fertiliser runoffs.
TAN is measured to understand the level of organic matter degradation and nitrogenous waste. It is necessary for soil and water testing for agriculture, as too much ammonia may worsen the soil quality and negatively affect the growth of plants.
Harm of Ammonia Nitrogen in Water
High levels of ammonia nitrogen in water are toxic to aquatic organisms. Un-ionised ammonia, in particular, is lethal to fish and other aquatic life even at low concentrations. It can disrupt ecosystems, reduce biodiversity, and cause algal blooms, which further deplete oxygen levels in water bodies.
It poses a risk for farmers as well. Contaminated water used for irrigation can affect soil microbiota and crop yields. This makes regular monitoring via wastewater testing not just an environmental concern but also an agricultural necessity.
Determination of Ammonia Nitrogen – Salicylate Method
The salicylate method of ammonia nitrogen determination is one of the most precise methods used in the water testing labs in Chennai. It is a colourimetric procedure in which ammonia reacts with salicylate with the help of a catalyst to form a complex of green-blue colour. This colour intensity is determined with a spectrophotometer and depends proportionally on the concentration of ammonia nitrogen.
The salicylate method is sensitive and reliable and is commonly employed in testing both soil and water in agriculture to make sure that the water used to irrigate crops does not harm crop health and ultimately the health of its human consumers.
Determination of Total Phosphorus (TP)
Total Phosphorus (TP) includes both organic and inorganic forms of phosphorus. The test is carried out by digesting the sample, and then a colourimetric test is done in which the orthophosphate is reacted with molybdate to produce a blue complex. Again, the concentration can be determined through spectrophotometric analysis.
In many parts of the agricultural sector, TP testing is done to ensure that the balance of nutrient supply to crops and healthy water used in irrigation is maintained. Hence, the scientific wastewater testing methods used are vital for sustainable agricultural practice.
Determination of Total Nitrogen (TN)
Total Nitrogen (TN) includes all forms of nitrogen present in wastewater, ammonia, nitrate, nitrite, and organic nitrogen. It is a comprehensive measure used to assess the overall nitrogen load, primarily from domestic sewage and agricultural run-off.
Determining TN typically involves two significant steps:
- Oxidation of all nitrogen forms to nitrate using digestion.
- Colourimetric analysis using reagents that react with nitrate to produce a measurable colour.
High levels of TN can severely affect drinking water safety, crop health, and aquatic systems.
Conclusion
Testing of wastewater is not just a requirement; it is a basic measure to safeguard our health, environment and agricultural economy. The four core wastewater testing methods discussed – Total Ammonia Nitrogen (TAN), the Salicylate method, Total Phosphorus (TP), and Total Nitrogen (TN) – provide an accurate insight into the quality and usability of water. In a nutshell, constant tests, routine care, and professional assessment are the keys to managing our most valuable resource.