New treatment method for domestic sewage

Abstract

Relating to environmental protection technologies, the invention provides a new treatment method for domestic sewage. The following problems exist in the existing domestic sewage treatment process: the competition of anaerobic phosphorus release and nitrogen removal by denitrification for carbon source; the metabolic cycle contradiction of nitrobacteria, heterotrophic bacteria and phosphorus-accumulating bacteria; the competition of nitrobacteria and heterotrophic bacteria for oxygen; and high energy consumption, high cost and troublesome operation. The method includes the steps of: letting domestic sewage enter an anaerobic tank, making the sludge-water mixed liquid of the anaerobic tank enter a sedimentation tank, enabling the supernatant of the sedimentation tank to flow automatically to an aerobic biofilm nitrification tank, simultaneously conducting aeration to supply oxygen, overflowing sludge into an anoxic tank, making the sludge-water mixed liquid of the anoxic tank enter a sedimentation tank, discharging the supernatant of the sedimentation tank, and letting the sludge flow back to the anoxic tank, with the effluent water meeting the first class A discharge standard of the national "pollutant emission standard for municipal wastewater treatment plants" (GB18918-2002). The method provided by the invention has the advantages of good sewage treatment effect, no need foradditional carbon source, low energy consumption, low process construction cost, convenient operation, environmental protection, and is conducive to improving the water environment quality.

Description

technical field [0001] The invention relates to environmental protection technology, in particular to a new method for domestic sewage treatment. Background technique [0002] With the rapid development of the economy, the eutrophication of water bodies is becoming more and more serious, such as Chaohu Lake, Taihu Lake and Dianchi Lake. Nitrogen and phosphorus are two important factors that cause water eutrophication, and many countries have strict restrictions on their discharge concentration. The Ministry of Environmental Protection of my country requires that when the effluent of urban sewage treatment plants is discharged into key river basins, lakes, reservoirs and other closed and semi-enclosed waters, the first-level A standard of "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002) must be strictly implemented . [0003] In order to meet the standard discharge of nitrogen and phosphorus in domestic sewage treatment, various places have ac...

AI Technical Summary

Problems solved by technology

However, for a long time, the C / N of urban domestic sewage in my country has been relatively low. More than 65% of sewage treatment plants have insufficient carbon sources. Nearly 43% of sewage treatment plants have influent C / N less than 3, and the carbon in sewage Sources can no longer meet the needs of microbial nitrogen and phosphorus removal

Therefore, using A 2 When the O process is used to treat domestic sewage, there is usually this outstanding problem: the competition between denitrification and denitrification and phosphorus removal microorganisms for carbon sources. Since the carbon source of urban sewage is generally low, it is difficult to meet the needs of nitrogen and phosphorus removal. Therefore, after treatment The sewage nitrogen and phosphorus are difficult to meet the discharge standards

In addition, this work also has the following disadvantages: the coexistence of different sludge age (Solids Retention Time, SRT) microorganisms has an adverse effect on the removal of nitrogen and phosphorus, and the generation time of phosphorus accumulating bacteria is short, which can be normal under the condition of short SRT. growth, and can obtain higher phosphorus removal efficiency, while nitrifying bacteria are autotrophic obligate aerobic bacteria, its growth rate is slow, the generation time is longer, and better denitrification can be obtained under the condition of longer SRT Therefore, the difference in SRT between nitrifying bacteria and phosphorus accumulating bacteria also leads to low nitrogen and phosphorus removal efficiency in domestic sewage

Although this process has achieved good results in the treatment of low C / N ratio domestic sewage, the process requires many structures (1 anaerobic tank, 1 aerobic nitrification tank, 1 anoxic tank, and a post-aeration tank 1, 3 sedimentation tanks), the operation consumes a lot of energy, and it is difficult to really apply it to the actual sewage treatment

Images