Pretreatment method of high-concentration cutting fluid sewage

Abstract

The invention discloses a pretreatment method of high-concentration cutting fluid sewage. The pretreatment method comprises the following steps: high-concentration cutting fluid sewage is inputted into a demulsification tank, a chemical oxidation pond, a flocculation basin and an air flotation tank so as to respectively carry out demulsification, chemical oxidation, flocculation, air flotation and the like; scum and bottom sludge which are discharged out of each treating pond are all connected into a nearby sludge collection tank by a self-flowing mode; and clean water flows into a clean water area of the air flotation tank from the outer periphery of an internal cylinder of the air flotation tank, and the clean water is injected through a clean water pipe into a clean water basin to be stored for the next regular treatment. In the air flotation tank, spiral-flow water distribution and dissolved air flotation technologies are combined, equipment is simplified, and the conventional air flotation treatment effect is improved. After high-concentration cutting fluid sewage is treated by the method, effluent COD can be reduced below 800 mg / L, thus satisfying inflow conditions of secondary sewage treatment. Thus, the method provided by the invention has characteristics of simplified equipment, reasonable technology and good treatment effect, and is very suitable for chemical pretreatment of metal working high-concentration cutting fluid sewage.

Description

technical field [0001] The invention relates to a sewage pretreatment method, in particular to a pretreatment method for high-concentration cutting fluid sewage. Background technique [0002] The waste water in the process of metal machining mainly comes from coolant, organic cleaning liquid, spray paint waste water, EDM working fluid, etc. The amount of organic matter is small but the concentration of organic matter is high, among which the cooling liquid COD Cr Up to tens of thousands or even hundreds of thousands. There is a bottleneck in the treatment of high-concentration mechanical processing wastewater in China, and many combined treatment processes can successfully reduce its COD Cr However, it is very difficult to achieve the follow-up treatment conditions of conventional sewage. In recent years, with the advancement of metal machining production technology, the emulsions used have become more stable and difficult to break. At the same time, this type of wastewat...

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Problems solved by technology

However, these methods are difficult to achieve long-term stable and effective treatment, and have the following disadvantages: 1. The effect of conventional destabilization and oil removal is not good; 2. Micro-electrolysis fouling and fouling are ineffective; 3. Activated carbon adsorption cannot be desorbed and regenerated; 4. The operating cost and investment cost of ultrafiltration reverse osmosis membrane technology are very high

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