Denitrification technology for printing and dyeing wastewater

Abstract

The invention discloses a denitrification technology for printing and dyeing wastewater. The technology comprises steps as follows: step 1, a denitrification system for the printing and dyeing wastewater is established and comprises an anaerobic hydrolysis tank, a low-oxygen tank, an aerobic tank and a denitrification filter which communicate with one another sequentially; step 2, the to-be-degraded printing and dyeing wastewater enters the anaerobic hydrolysis tank from a water inlet of the anaerobic hydrolysis tank, 5%-10% of sewage after hydrolysis directly enters the denitrification filter, and residual sewage flows into the low-oxygen tank; step 3, the sewage flows into the aerobic tank for denitrification treatment via the low-oxygen tank, residual sludge produced by the aerobic tank and a nitrification liquid flow back to the anaerobic hydrolysis tank in the ratio being 25%-35%, and the residual nitrification liquid flows into the denitrification filter; step 4, a sludge and water mixture obtained through backwashing by the denitrification filter also flows back to the anaerobic hydrolysis tank in the ratio being 15%-25%, and residual sewage is discharged out of the system after denitrification filtration. The technology has the advantages of good treatment effect, low sludge yield, small occupied area of the system and low operation cost.

Description

technical field [0001] The invention relates to a denitrification process for printing and dyeing wastewater, which belongs to the technical field of wastewater treatment. Background technique [0002] Printing and dyeing wastewater is wastewater with a high nitrogen content. The excessive discharge of nitrogen-containing wastewater is one of the main causes of water pollution. The harm it brings to the water body is mainly manifested in eutrophication, black and odorous water. "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002) has more and more stringent control over the discharge of nitrogen and other nutrient elements. In the printing and dyeing process, due to the use of a large number of dyes and auxiliaries, including a large amount of azo dyes and Urea, which increases the content of organic nitrogen in wastewater to a certain extent. The existing denitrification processes, such as A2 / O, UCT, CASS / CAST, SBR, etc., are all based on the tr...

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Problems solved by technology

[0004] In terms of short-range nitrification and denitrification technology research, the current research on short-range nitrification and denitrification is mainly carried out in the SBR form of sequencing batch reactor and the SHARON process is used to treat sludge digestion liquid, and few use continuous The report on the study of short-range nitrification and denitrification using immobilized microorganism technology has become one of the hot spots in the field of biological denitrification in the past ten years. The method is to use immobilized carriers to layer nitrifying bacteria and denitrifying bacteria Buried or mixed embedding, aerobic nitrifying bacteria are concentrated in the outer layer, denitrifying bacteria are concentrated in the inner layer, providing suitable conditions for nitrification and denitrification respectively, but there is an obstacle in this technology, when the embedded microorganisms pass through for a period of time After operation, the activity will decrease, and the corresponding biological denitrification performance will decrease

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