Electronic Industrial Park Wastewater Treatment

1. Project overview

Electronics Industrial Park includes chip packaging and testing area, PCB area and smart home appliance manufacturing area. In the daily production and operation process of enterprises in the park, a large number of high-concentration wastewater will be generated, and the wastewater is of many types and the water quality is complex. Liyuan environmental Protection will not pretreat the wastewater of various types, and then carry out biochemical treatment and deep treatment according to the situation of the park. Finally, the water reaches the reuse standard.

2. Design inlet and outlet water quality

According to the information provided by the owner, combined with the analysis of the actual operation experience of Liyuan Environmental Protection in the past, it is decided to design the influent water quality as follows:

pH: 6-9

COD: 30000mg/L

Ammonia nitrogen: 100mg/L

After the wastewater is treated by the sewage treatment station, it meets the "Discharge Standard of Electroplating Water Pollutants" and is discharged into the municipal sewage network and industrial sewage treatment plant for phase II treatment. The specific influent indicators are as follows:

pH: 6-9

SS: ≤60mg/L

CODcr: ≤100mg/L

Ammonia nitrogen: ≤16mg/L

Total nitrogen: ≤30mg/L

Total phosphorus: ≤1.0mg/L

Total nickel: ≤0.1mg/L

Total silver: ≤0.1mg/L

Total chromium: ≤0.5mg/L

Hexavalent chromium: ≤0.1mg/L

Total copper: ≤0.3mg/L

Total cyanide (in CN) : ≤0.2mg/L

3. Technical analysis of wastewater treatment process

In the wastewater treatment project of the electronic industrial park, different types of pre-treated sewage are sent to the biochemical regulating tank, the water quality and quantity are adjusted, appropriate nutrients are added, and then the biochemical regulating tank lift pump is pumped into the ph regulating tank 1 and acidic agents are added to adjust the ph, and then the ph regulating tank 2 and alkaline substances are added to adjust the acid and alkaline of the comprehensive wastewater. The effluent from the ph regulating tank 2 is sent to the transfer tank. The comprehensive waste water pump is pumped into the air flotation treatment system through the lifting pump of the transfer tank, the PH is adjusted in the air flotation tank 3, and the reagent is added to react with the treated water. The solid particles in the waste water condense in the reaction, forming flocculant alum. After mixing with the pressurized dissolved gas, the dissolved gas sticks to the flocculant to form an upward trend, and then enters the separation area of the air flotation device. The flocculant rises to the liquid level to form a separation layer, so as to remove solid impurities, insoluble suspended matter and oil in the wastewater, so that the treated water body is clear and transparent, and the scum of the air flotation system is automatically scraped out to the physicochemical organic sludge tank through the slag scraper, and the treated effluent is sent to the anaerobic reaction tank.

The wastewater flows into the bottom of the sludge bed of the anaerobic reaction tank and is mixed with the granular sludge layer and suspended sludge layer. The efficient degradation of the granular sludge provides the substrate for the methanation stage in the mixed anaerobic digestion process. Under the action of methanogens, most of the organic matter in the sewage is decomposed into carbon dioxide and methane, and most of the organic pollutants are removed. Reduce the subsequent biochemical tank processing load.

The wastewater is fully in contact with the anaerobic granular sludge in the anaerobic reaction tank, and the anaerobic digestion liquid separated by the three-phase separator is discharged into the anaerobic regulation tank, and then back into the internal system of the anaerobic reactor, and a part is discharged into the anoxic tank for subsequent treatment.