Decarbonization and total nitrogen removal treating process for semi-coking wastewater

Abstract

The invention discloses a decarbonization and total nitrogen removal treating process for semi-coking wastewater. The process sequentially comprises a pretreatment system, a biochemical treatment system and a deep treatment system, wherein the pretreatment system comprises an oil separation tank and cavitation air flotation tanks of two stages; the biochemical treatment system at least comprises an aerobic pool, a facultative tank and a precipitation tank; the deep treatment system at least comprises a photocatalytic ozone oxidation reaction tower, and ozone enters water through a microporous aeration disc from the lower end of the photocatalytic ozone oxidation reaction tower; a gas collecting pipe is arranged at the top of the photocatalytic ozone oxidation reaction tower and is used for collecting residual ozone overflowing from a water surface and then leading the collected residual ozone into a first-stage cavitation air flotation tank. The residual ozone is introduced to an air flotation section of the first-stage cavitation air flotation tank, so that the ozone is recycled, the deoiling effect of the air flotation section is improved, meanwhile, the removal amount of harmful substances is increased, and the load of treatment of a biochemical end is reduced. Aiming at the semi-coking wastewater, the process is good in treatment effect, strong in adaptability and convenient in operation and is stable and reliable.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a decarbonization and total nitrogen removal process for semi-carbon wastewater. Background technique [0002] Semi-coke, also known as semi-coke, is a low-volatility solid carbonaceous product obtained by pyrolysis of long-flame coal, non-caking coal and weakly caking coal, etc. Coking wastewater is similar. The carbonization temperature in coke production is about 1000 ℃, while the carbonization temperature in semi-coke production is low. Therefore, semi-coke wastewater contains a large number of low- and medium-molecular pollutants that have not been oxidized by high temperature, and its concentration is about 10 times higher than that of coking wastewater. Semi-coke wastewater mainly contains high concentrations of organic and inorganic substances, which are highly toxic pollutants and are generally difficult to treat and reuse. It mainly contains c...

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Problems solved by technology

[0003] Existing semi-coke enterprises mostly use physical, chemical and biological methods for wastewater treatment systems: the main treatment methods include adsorption method, flue gas treatment method, activated sludge method, incineration method, catalytic oxidation-biochemical method, ammonia distillation Dephenol-SBR method and emulsion liquid membrane method, etc., they have problems: high investment cost, high treatment cost, poor applicability, difficult treatment or secondary pollution, such as high treatment cost of adsorption method, difficult adsorption regeneration , is not suitable for high-concentration wastewater treatment. The flue gas method requires that the ammonia content in the wastewater must be balanced with the amount of ammonia required by the flue gas, and its use is limited; the incineration method has a large investment, high requirements for water quality, and poor applicability; catalytic The oxidation method needs to be carried out under high temperature and high pressure conditions, and the treatment cost is high, and the investment scale and operation cost are large; the ammonia distillation and dephenolization-SBR method needs to use an organic solvent for dephenolization, which will cause secondary pollution, and the ammonia nitrogen will be affected after the dephenolization treatment. The treatment efficiency increases the difficulty of subsequent treatment, which may make the effluent unable to meet the direct discharge standard in Table 2 of the "Coking Chemical Industry Pollutant Discharge Standard" GB16171-2012

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