Chemical wastewater pretreatment physicochemical process recommended:

I. Catalytic Microelectrolysis Technology

[Technical Background]

The treatment of organic wastewater, especially high salinity and high concentration organic wastewater, has been a difficult problem for many environmental protection workers and management departments in China. With the rapid development of China's chemical industry, various new chemical products have been applied to all walks of life, especially in heavy polluted industries such as medicine, chemical industry, electroplating, printing and dyeing. While improving product quality and quality, they also bring increasingly serious environmental pollution problems. The main manifestations are: high concentration of organic pollutants in wastewater, stable structure, poor biochemical property, and difficult conventional process. Achieving standard discharge and high cost of treatment bring great pressure to energy saving and emission reduction of enterprises.

[Technical overview]

Microelectrolysis technology is an ideal process for treating high concentration organic wastewater. It can not only greatly reduce COD and chroma, but also greatly improve the biodegradability of wastewater when applied to the treatment of high salinity, refractory and high chroma wastewater. This technology is to treat wastewater by using "galvanic cell" effect produced by filling microelectrolytic fillers in microelectrolysis equipment without power supply. When water is supplied, numerous "primary batteries" with potential difference of 1.2V will be formed in the equipment. Primary batteries use wastewater as electrolyte, and electrolytic oxidation and reduction of wastewater are carried out by discharging current to achieve the purpose of degradation of organic pollutants. The new ecology [O H], [H], [O], Fe2+, Fe3+ produced in the process of treatment can react with many components in wastewater, such as destroying the chromophore or chromophore groups of the colored substances in the wastewater, or even breaking the chain, so as to achieve decolorization and degradation; the formed Fe2+ is further oxidized to Fe3+, and their hydrates have strong adsorption-flocculation activity. In particular, after the addition of alkali to adjust the pH value, iron hydroxide and ferric hydroxide colloid flocculants are formed. Their flocculating ability is much higher than that of the iron hydroxide colloid obtained by the General Pharmaceutical hydrolysis, which can flocculate small particles, metal particles and organic macromolecules in the water. The working principle is based on the combined action of electrochemistry, oxidation reduction, physics and flocculation and sedimentation. The process has the advantages of wide application range, good treatment effect, low cost, short treatment time, convenient operation and maintenance, low power consumption and so on. It can be widely used in the pretreatment and advanced treatment of industrial wastewater.

[Technical characteristics]

(1) The reaction rate is fast, and the general industrial wastewater only needs half an hour to several hours.

(2) There are a wide range of organic pollutants, such as refractory organic compounds containing even fluorine, carbon double bonds, nitro and halogenated groups, which have good degradation effect.

(3) The process flow is simple, the service life is long, the investment cost is small, the operation and maintenance is convenient, the operation cost is low, and the treatment effect is stable. Only a small amount of microelectrolytic filler is consumed in the treatment process. Fillers need only be added regularly without replacement, and can be added directly.

(4) After micro-electrolysis treatment, the wastewater will form original ferrous or iron ions in the water, which has better coagulation effect than ordinary coagulants. Without adding coagulants such as iron salts, COD removal rate is high, and it will not cause secondary pollution to the water.

(5) It has good coagulation effect, high removal rate of chroma and COD, and the same amount can greatly improve the biodegradability of wastewater.

(6) This method can achieve the effect of phosphorus removal by chemical precipitation and heavy metals removal by reduction.

(7) The technology can be used as the pretreatment of the wastewater from the high-concentration organic wastewater treatment project which has been built up, so as to ensure the stable discharge of the wastewater after treatment. Some wastewater with high concentration in production wastewater can also be separately extracted for micro-electrolysis treatment.

(8) Each unit of the technology can be used as a separate treatment method and a pretreatment process for biological treatment, which is beneficial to sludge sedimentation and biofilm formation.

[Applicable wastewater types]

(1) Dyestuff, chemical and pharmaceutical wastewater; coking and petroleum wastewater;

The BOD/COD value of the wastewater treated above has been greatly increased.

(2) Printing and dyeing wastewater; Leather wastewater; Papermaking wastewater and wood processing wastewater;

It has a good application in decolorization, and can effectively remove COD and ammonia nitrogen.

(3) Electroplating wastewater; Printing wastewater; Mining wastewater; Other wastewater containing heavy metals;

Heavy metals can be removed from the above wastewater.

(4) Organophosphorus agricultural wastewater; Organochlorine agricultural wastewater;

----- greatly improving the biodegradability of the above wastewater, and removing phosphorus and sulfide