The characteristics of industrial effluent vary according to industries, but domestic effluent is not, it always has the same characteristics so it would be foolish to compare between two.
The pollutants in domestic effluent are always same; it contains human waste, kitchen waste, laundry detergents, etc., so the pollution standards are not too high, but I want to add one thing that definitely the pollution load in terms of pollutants is less, but the pollution hazard is more because of its huge quantity. The below table shows the daily sewage generated in India (Urban Areas). Source website “ENVIS Centre on Hygiene, Sanitation, Sewage Treatment Systems and Technology” Ministry of Environment, Forest & Climate Change.”
Domestic Effluent Characteristics:
Temperature : In practical the temperature of the raw sewage is in between 15 to 350C but it varies as per the weather conditions.
PH: Fresh sewage does have neutral pH (5.5-8.0). It may reduced after a few hours due to the decomposition of organic matter by natural microbes.. If there are fluctuations in pH then it means some industrial effluent is coming in sewage.
Color andOdour : Fresh sewage looks like soapy and cloudy. It becomes gray & black after a few hours of retention. Old sewage has a pungent smell of H2S gas.
Solids: Sewage contains grit,slit , sand and other settable solids. The quantity of biodegradable solids content is less than 0.5 % of the total.
Nitrogen and Phosphorus: The main nitrogen source in sewage are proteins, amines, amino acids, and urea. These compound forms ammoniacal nitrogen after bio-degradation. The nitrogen content in sewage is observed in a range between 20 to 50 mg/L. Phosphorus containing food waste is the source of phosphorus in sewage. The synthetic detergents are also a very good source of phosphorus. The concentration of PO4 in raw sewage may in the range of 5 to 10 mg/L.
Chlorides: The chloride concentration in sewage is always more than the chloride concentration of water used in houses. Chlorides are the most stable compound with water, it generally combines with sodium & potassium, magnesium and calcium.
Organic Material: Sewage mainly contains 99% of water & leftover are organic & inorganic substances which are in suspension, colloidal & in dissolved form. Carbohydrates,lignin , fats, soaps, synthetic detergents, proteins and their decomposition products are the main organic substances present in sewage. We can measure the organic material of sewage by BOD & TOC tests. The pollution strength of sewage is mentioned in the table. The parameters are not exact; it will vary according to cities.
Temperature
PH: Fresh sewage does have neutral pH (5.5-8.0). It may reduced after a few hours due to the decomposition of organic matter by natural microbes.. If there are fluctuations in pH then it means some industrial effluent is coming in sewage.
Color and
Solids: Sewage contains grit,
Nitrogen and Phosphorus: The main nitrogen source in sewage are proteins, amines, amino acids, and urea. These compound forms ammoniacal nitrogen after bio-degradation. The nitrogen content in sewage is observed in a range between 20 to 50 mg/L. Phosphorus containing food waste is the source of phosphorus in sewage. The synthetic detergents are also a very good source of phosphorus. The concentration of PO4 in raw sewage may in the range of 5 to 10 mg/L.
Chlorides: The chloride concentration in sewage is always more than the chloride concentration of water used in houses. Chlorides are the most stable compound with water, it generally combines with sodium & potassium, magnesium and calcium.
Organic Material: Sewage mainly contains 99% of water & leftover are organic & inorganic substances which are in suspension, colloidal & in dissolved form. Carbohydrates,
Industrial Effluent Characteristics:
Industrial effluent characteristics are not same it varies according to industry. It contains organic, inorganic, heavy metals, colour and oil & grease. The organic & inorganic substances found in the suspended & dissolved form. The pollution strength of few important industries are as in the table: I have tried to give exact data, but the pollution load is not always same, fluctuation is always there:
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