1, sewage treatment biological treatment method
biological treatment is to use microbes to absorb, decompose and oxidize the organic matter in the sewage, and degrade the unstable organic matter into a stable and harmless substance, so that the sewage is purified. modern biological treatment methods can be divided into two categories: oxygen oxidation and anaerobic reduction according to the different microorganisms. the former is widely used to treat municipal wastewater and organic industrial waste water. aerobic oxidation is widely applied and contains many kinds of arts and crafts and structures. biofilm process (including biological filter, biological turntable), biological contact oxidation and other processes and structures. both activated sludge and biofilm are artificial biological treatments. there are also natural biological treatments for farmland and ponds, namely irrigated fields and biological ponds. biological treatment is the most widely used sewage treatment method because of its low cost.
2, what is the amount of waste water treatment or bod5 removal and treatment quality?
sewage treatment capacity or bod5 removal capacity: the daily total sewage flow (m3/d) into the sewage treatment plant can be used as an indicator of the capacity of the sewage treatment plant. the total amount of bod5 removed daily can also be used as an indicator of sewage treatment capacity. the total amount of bod5 removed is equal to the product of the difference between bod5 and kg/d, which is treated as a unit of kg/d or t/d.
quality of treatment: the two level sewage treatment plant takes the factory bod5 and ss value as the quality indicators. according to the newly developed effluent discharge standard of the sewage treatment plant, the effluent bod5 and ss of the two grade sewage treatment plants are all less than 30mg/l. the treatment quality can also be measured by the removal rate. the removal rate is removed by inflow concentration and water concentration. the effluent value or removal rate of ammonia nitrogen and tp is also applied to the treatment of quality indicators.
3. what is the ph value and its directive significance?
ph indicates the degree of acid and alkalinity of sewage. it is the value of the reciprocal number of hydrogen ion concentration in water, its range of 0~14, ph value equal to 7, the water is neutral, less than 7 is acidic, the smaller the value, the stronger the acidity, more than 7 is alkaline, the greater the value, the stronger the alkalinity. the ph value of sewage has a certain effect on pipes, pumps, gate valves and sewage treatment structures. the ph value of domestic sewage treatment plants is usually 7.2~7.8. too high or too low ph can indicate the entry of industrial wastewater. too low a value will corrode the pipeline, pump body and may cause harm. for example, sulfide in sewage will generate h2s gas under acidic conditions. high concentration causes headache, runny nose, asphyxia and even death. therefore, it is necessary to strengthen monitoring, find sources of pollution and take countermeasures to reduce ph. at the same time, the allowable range of ph for biochemical treatment is 6~10, too high or too low can affect or destroy biological treatment.
4. what is the total solid (ts)?
it refers to the total amount of solid water evaporated from the water bath to dry at 100 c. it is the sum of dissolved solids and non soluble solids in sewage. it can reflect the total concentration of solid in the polluted water. the analysis of the solid in and out water can reflect the effect of sewage treatment structures on total solids removal.
5. what is a suspended solid (ss)?
it refers to the quantity of solid matter trapped in the sewage. part of suspended solid can be precipitated under certain conditions. determination of suspended solids is usually carried out with asbestos filtration. the main equipment is the ancient crucible. when the laboratory equipment is not available, filter paper can also be used as a filter, from the total solid and dissolved solid reduction to obtain the suspended solid content. when measuring suspended solids, the difference is often greater because of the different filters.
this index is one of the most basic data of sewage. the suspension solid determination of water and water can be used to reflect the condition that the suspended solids decrease after the treatment of the sewage through the initial sedimentation tank and the two sink is treated. it is the main basis for the construction of the sedimentation efficiency.
6. what is chemical oxygen demand (cod)
chemical oxygen demand (cod) refers to the amount of oxidant needed to oxidize organic matter in sewage by chemical means. using potassium permanganate as oxidant, the result is customarily called oxygen consumption, expressed in oc. with potassium dichromate as oxidant, the measured results are called cod, the difference between the two is the choice of oxidant. using potassium permanganate as an oxidant, it can only oxidize straight chain organic compounds in sewage, and potassium dichromate is an oxidizing agent, which is more powerful and complete than the former. besides the organic compounds, it can oxidize many complex organic compounds that can not be oxidized by potassium permanganate. therefore, the cod value of the same sewage is much larger than the value of oc. especially when a large number of industrial wastewater enters the sewage plant, the chemical oxygen demand of the potassium acid method should be measured. the cod value of a municipal sewage plant is generally about 400~800mg/l.
the consumption value of potassium permanganate method is often used as reference data for determining the dilution ratio of five days biochemical oxygen demand in sewage treatment plants.
7. what is biochemical oxygen demand (bod)?
biochemical oxygen demand (bod) refers to the amount of oxygen needed by microorganisms in water to decompose organic matter under aerobic conditions. it is an indirect indicator of the pollution degree of organic matter. the biochemical oxidation decomposition of organic matter usually has two stages. the first phase is mainly the oxidation of carbon containing organic matter. it is called the carbonization stage, which takes about 20 days to complete. the second stage is mainly the oxidation of nitrogenous organic matter, which is called nitrification stage, which takes about 100 days to complete. it is generally accepted that the standard practice is to incubate at 20 c for 5 days to determine the measured data called five-day bod. bod5 is therefore referred to as "bod5".
