Papermaking wastewater is harmful, the black liquor is the most harmful pollutants, it contains accounted for more than the total emissions of the pollution of papermaking black liquor as 90%, alkaline, deep color, smell heavy, foam, and consume a large amount of dissolved oxygen in water, serious water pollution, which is harmful to environment and human health. The most serious pollution to the environment in the middle of the bleaching process of chlorine wastewater.
 

1 workshop wastewater by gravity ditch into the sump, the grill is arranged in trenches, with thick suspended closure;

2 use the pump to collect the waste water into the flotation tank, after flotation, part of the pulp transported back to the workshop;

3 of the waste water through the flotation tank, into the hydrolysis acidification tank, large organic molecules will be difficult to decompose into easy degradation of small organic molecules or CO2 and H2O, greatly improve the biodegradability of wastewater;

4 wastewater into the contact oxidation pool, the organic matter in wastewater under aerobic conditions, aerobic bacteria are decomposed into CO2 and H2O, thereby removing organic matter.

5 wastewater after biochemical treatment, flow into the two sedimentation tank, biological membrane in biochemical treatment stage falling precipitation separation, the supernatant from the bottom sludge into the sludge treatment system, part of the sludge reflux to hydrolytic acidification;

6 the surplus sludge in the air floatation tank and the two sedimentation tank is pumped into the sludge thickening tank by a pump to reduce the sludge treatment volume, and the sewage sludge is dewatered by the pump. The concentrated supernatant and filter water discharged into the water collecting well, with wastewater treatment.