1. Chemical wastewater treatment
Acid and alkali wastewater treatment. First, discharge the acidic wastewater (or alkaline wastewater) into the neutralization tank, and then discharge the alkaline wastewater (or acidic wastewater), stir and neutralize, and discharge it after the pH value reaches 6-9.
Inorganic wastewater treatment. The main pollutants of inorganic wastewater are acid or alkali, suspended matter, dissolved salt, etc. For acid or alkali, neutralization method (neutralization precipitation method) can be used for treatment. When the concentration of acid or alkali is too high, recycling should be considered. For suspended matter or colloid, precipitation, coagulation and other methods can be used to remove it, while the removal of dissolved salts should mainly rely on adsorption, ion exchange, electrodialysis and other methods.
Organic wastewater treatment. Organic wastewater refers to the wastewater from organic acid washing of boilers, which is treated by evaporation in evaporation tanks.
2. Treatment of oily wastewater
High-efficiency flotation method
This method uses the SPD type high-efficiency flotation device and utilizes its special "zero speed" principle: the raw water enters from the central rotating head of the flotation tank and distributes water through the water distributor. The moving speed of the water distributor is the same as the flow rate of the incoming water, but in the opposite direction, resulting in "zero speed". In this way, the incoming water will not disturb the raw water, so that the suspension and sedimentation of particles are carried out in a static state. Qinhuangdao Thermal Power Plant uses this method to treat and recycle industrial wastewater in the plant. It no longer discharges sewage to the original sewage outlet Xinkai River, reducing pollution to the Bohai Bay and having obvious environmental benefits. In short, for the emulsified oil in the oily wastewater of the power plant, the flotation method is generally used to remove it, and the oil removal efficiency is relatively high. The figure below shows the process of industrial wastewater treatment and recycling of Anyang Power Plant...
The correct and reasonable use of flotation method to treat oily wastewater is the key to meeting the effluent standards. The key to the reasonable use of flotation method lies in the control of the dosage and the pH range at the optimal dosage. In the treatment project of oily wastewater in Nankou Locomotive Depot, basic aluminum chloride is used as a coagulant. It is an inorganic polymer coagulant. If the dosage is too little, the coagulation effect will not be achieved; if the dosage is too much, the flocculation effect will be reduced or even stabilized again. Through the exploration of dosage and optimal pH range during the debugging process, it is proposed that the dosage is 0.01%-0.02%, and the pH value of the effluent is controlled in the range of 6.5-7.0, the effluent effect is the best, and the oil content of the effluent can be maintained at 3-5mg/l.
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