Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Oxygen Demand (TOD), Total Organic Carbon (TOC), Total Nitrogen (TN), Total Phosphorus (TP), pH, Heavy Metals.
Physical Indicators
Temperature, color, smell and taste, and three forms of existence of solid matter: suspended, colloidal, and dissolved. Solids use total solids (TS) as an indicator, and suspended solids (SS) are commonly used in wastewater treatment to indicate the content of solids (TDS indicator is higher than 1000 or more).
Chemical indicators
I, chemical oxygen demand (COD): refers to the use of strong chemical oxidant (China's legal use of potassium dichromate) in acidic conditions, the organic matter oxidized into CO2 and H2O by the amount of oxygen consumed (mg / L), expressed in CODcr, abbreviated as COD. the higher the chemical oxygen demand, indicating that the more organic pollutants in the water, the more serious pollution.
Two, biochemical oxygen demand (BOD): organic pollutants in the water is aerobic microbial decomposition of the amount of oxygen required is called biochemical oxygen demand (mg / L).
If the composition of the sewage is relatively stable, then, in general, COD> BOD. general BOD/COD is greater than 0.3, considered suitable for biochemical treatment.
Three, total oxygen demand (TOD): the main elements of organic matter is C, H, O, N, S, etc., when the organic matter is oxidized in its entirety, will produce CO?, H?O, NO, SO? etc., respectively, at this time the oxygen demand is known as total oxygen demand (TOD).
Four, total organic carbon (TOC): including water samples of all organic pollutants in the carbon content, but also to evaluate the quality of organic substances in water samples of a comprehensive parameter.
Fifth, total nitrogen (TN): sewage containing nitrogen compounds are divided into organic nitrogen, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, the total amount of four nitrogen-containing compounds known as total nitrogen (TN). Kjeldahl nitrogen (TKN) is the sum of organic nitrogen and ammonia nitrogen.
Six, total phosphorus (TP): including organic phosphorus and inorganic phosphorus two categories.
seven, pH.
VIII. heavy metals.
Biological indicators
I. Coliforms: the number of coliforms contained in each liter of water samples, in terms of a / L.
Second, the total number of bacteria: is the number of coliform bacteria, pathogenic bacteria, viruses and other bacteria, the total number of bacterial colonies per milliliter of water samples. p>Life sewage, livestock and poultry farm sewage, as well as tanning, wool washing, slaughter industry and hospitals and other wastewater discharged, often contains a variety of pathogens, such as viruses, bacteria, parasites. Pollution of water bodies by pathogens can spread diseases such as schistosomiasis, cholera, typhoid, dysentery and viral hepatitis. Some of the plagues that have been prevalent throughout history are water-borne infectious diseases.
such as 1848 and 1854, two cholera epidemics in the United Kingdom, the death of more than 10,000 people; 1892 German cholera epidemic in Hamburg, death of more than 750 people, are caused by water pollution. Contaminated by pathogens after the water body, microbial surge, many of which are pathogenic bacteria, pathogenic eggs and viruses, they tend to exist with other bacteria and E. coli ****, so the total number of bacteria and E. coli index and the number of bacterial value is usually specified as a direct indicator of pathogen contamination.
Pathogen contamination is characterized by:
(1) large number;
(2) wide distribution;
(3) longer survival time;
(4) rapid reproduction;
(5) easy to produce resistance, it is difficult to extinction;
(6) the traditional secondary biochemical wastewater treatment and chlorination disinfection, some pathogenic microorganisms, viruses are still able to survive in large numbers. survive.
The common coagulation, sedimentation, filtration, disinfection treatment can remove more than 99% of the virus in the water, such as turbidity greater than 0.5 degrees, will still be accompanied by virus penetration. Pathogenic pollutants can enter the water body through a variety of ways, once the conditions are suitable, it will cause human disease.
Baidu Encyclopedia - Wastewater