City living sewage treatment process

Abstract

The invention provides a city living sewage treatment process which comprises the following steps: dividing pretreated living sewage into two parts, and carrying out respective nitrogen and phosphorusremoval, namely feeding a part of the living sewage into a first anoxic pond, a second anoxic pond and a first aerobiotic pond in sequence; feeding the other part of the living sewage into an anaerobic pool and a second aerobiotic pond in sequence; backflowing a part of a mixed liquid in the first aerobiotic pond into the second anoxic pond; backflowing a part of a mixed liquid in the second anoxic pond into the first anoxic pond; backflowing a part of a mixed liquid in the first anoxic pond into the anaerobic pool; backflowing a part of a mixed liquid in the second aerobiotic pond into the second anoxic pond; effluents of both the first aerobiotic pond and the second aerobiotic pond are fed into a homogenization adjusting tank. By adopting the city living sewage treatment process provided by the invention, the nitrogen and phosphorus removal efficiency can be improved, ammonia nitrogen in living sewage can be rapidly and effectively removed, and effluent indexes meet standards of grade A in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).

Description

technical field [0001] The invention belongs to the field of sewage treatment, in particular to a treatment process for urban domestic sewage. Background technique [0002] Domestic sewage is mainly various detergents and sewage, garbage, feces, etc. used in urban life, mostly non-toxic inorganic salts, domestic sewage contains a large amount of organic matter, such as cellulose, starch, sugar and fat protein, etc.; It also often contains pathogenic bacteria, viruses and parasite eggs; inorganic salts of chloride, sulfate, phosphate, bicarbonate and sodium, potassium, calcium, magnesium, etc. The general feature is high nitrogen, sulfur and phosphorus content, and under the action of anaerobic bacteria, it is easy to generate odorous substances. Therefore, domestic sewage needs to be treated. [0003] At present, the most typical process of nitrogen and phosphorus removal in sewage treatment is A 2 O technology, yet this technology at least has the following defects: (1) ...

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Problems solved by technology

[0003] At present, the most typical process of nitrogen and phosphorus removal in sewage treatment is A 2 O technology, yet this technology at least has the following defects: (1) the impact of dissolved oxygen and nitrate - the concentration of dissolved oxygen in the anaerobic zone and the concentration of nitrate are too large, which will inhibit the growth of phosphorus-accumulating bacteria; the oxygen in the anoxic zone will interact with Nitrate competes for electron donors, and inhibits the formation and activity of nitrate reductase, which is not conducive to denitrification; dissolved oxygen and nitrate in the aerobic zone are brought into the anaerobic tank by the external return sludge, affecting the anaerobic tank. The full release of phosphorus; (2) the impact of carbon sources—the phosphorus accumulating bacteria in the anaerobic zone can only absorb soluble low-molecular-weight organic substrates to synthesize PHB, and the denitrification in the anoxic zone requires a large amount of organic carbon sources as electron donors. There are too few organic carbon sources in the area, and the phosphorus-accumulating bacteria release the absorbed phosphorus due to endogenous respiration

If the sand in the sewage enters the follow-up treatment unit, it will affect the operation of the follow-up treatment unit, causing various hazards such as excessive wear of the delivery pump and sludge dewatering equipment

There are about 10% organic matter in the grit grains of ordinary advection grit chambers, and the interception effect on the sand grains coated with organic matter is not good.

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