The wastewater discharged by coal chemical enterprises is mainly concentrated gas washing wastewater, which contains a lot of toxic and harmful substances such as phenol, cyanide, oil and ammonia nitrogen. In the comprehensive wastewater, CODcr is generally about 5000mg/l, and ammonia nitrogen is 200~500mg/l. The organic pollutants contained in the wastewater include phenols, polycyclic aromatic compounds and heterocyclic compounds containing nitrogen, oxygen and sulfur, etc., which is a typical industrial wastewater containing organic compounds that are difficult to degrade.
At present, the main technology for the treatment of coal chemical wastewater in China is biochemical method, which has a good effect on the removal of phenols and benzenes in wastewater, but has a poor effect on the treatment of some refractory organic compounds such as quinolines, indoles, pyridines, carbazole, etc., which makes it difficult for the coal chemical industry to reach the first-level standard for external drainage CODcr. At the same time, after biochemical treatment, coal chemical wastewater has the characteristics of high chroma and turbidity.
Therefore, in order to achieve reuse or discharge standards after treatment of such coal gasification wastewater, CODcr, ammonia nitrogen, chroma and turbidity are mainly further reduced. It is necessary to pre-treat before biochemical treatment, and the agent usually selected during pre-treatment is very key. Coagulants such as aluminum salt, iron salt, polyaluminum, polyiron and polyacrylamide are generally added to strengthen the precipitation effect. The decolorizing agent developed and produced by our company is a combination of the above several agents. It is only necessary to add about 0.5-3 parts per thousand to achieve the same or even better effect than the above agents.
Decolorizing agent is a process of solid-liquid separation by using the sedimentable properties of suspended matter in water, electrolyzing it into small particles, and then sinking it under the action of gravity through flocculation precipitation. The aim is to remove suspended organic matter in order to reduce the organic load of subsequent biochemical treatment.
As a front-end pretreatment agent for coal chemical wastewater, decolorizing agent can demulsification and decolorization of wastewater, but also reduce the high COD, SS and other organic matter in coal chemical wastewater, so the choice of front-end pretreatment agent is also extremely important, the right choice solves the problem, but also reduces the cost.
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