Pulping and papermaking wastewater treatment project of a paper mill in Kunming, Yunnan
Pulping and papermaking wastewater treatment project of a paper mill in Kunming, Yunnan
Pulping and papermaking wastewater treatment project of a paper mill in Kunming, Yunnan

Pulping and papermaking wastewater treatment project of a paper mill in Kunming, Yunnan

Yunnan Kunming Paper Mill Co., Ltd. is a large-scale pulp and paper enterprise that produces bamboo and wood paddles using eucalyptus, pine, and bamboo raw materials, with an annual output of approximately 150000 tons. In the papermaking sector, we use self-produced bamboo and wood pulp and waste paper pulp as raw materials to produce kraft cardboard, with an annual output of approximately 320000 tons.

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案例詳情

1、 Project Overview
Yunnan Kunming Paper Mill Co., Ltd. is a large-scale pulp and paper enterprise that produces bamboo and wood paddles using eucalyptus, pine, and bamboo raw materials, with an annual output of approximately 150000 tons. In the papermaking sector, we use self-produced bamboo and wood pulp and waste paper pulp as raw materials to produce kraft cardboard, with an annual output of approximately 320000 tons. Pulping wastewater contains lignin, residual cellulose and hemicellulose, tannin compounds, resin compounds and chlorides that are difficult to be biodegraded. Paper wastewater contains small fibers, impurities in waste paper, and a small amount of organic pollutants such as pectin, wax, and sugars.
The scale of wastewater treatment is 1500m3/d for the pulping section and 1000m3/d for the papermaking section, in accordance with the "Discharge Standards for Water Pollutants in the Pulping and Papermaking Industry" (GB3544-2008). The raw water quality and discharge standards are shown in the following table:

 

project COD（mg/L） BOD5（mg/L SS（mg/L） Chromaticity (mg/L) Water temperature (℃) pH
pulping wastewater 1500 500 400 300 65

6~9
papermaking wastewater 5000 1500 3500 - 50 6~9
emission standard 90 20 30 50 - 6~9

 

2、 Design Features
1) Pulping wastewater treatment
a. The quantity and quality of pulping wastewater in this project vary greatly, and a regulating tank with a large retention time and an accident emergency tank have been set up to cope with the impact of changes in quantity and quality and impact loads;
b. The aerobic biological treatment system used in this project is relatively sensitive to the inlet water temperature, while the water temperature of pulping wastewater is generally ≤ 65 ℃. Therefore, a cooling tower is set up before biological treatment to ensure the stable operation of the subsequent treatment system;
c. Pulping wastewater contains fibrous suspended solids, and the use of chemical coagulation sedimentation method can remove most of the pollutants such as S S and degrade some COD, improving the quality of subsequent biological treatment influent water;
d. Adopting an A/0 biological treatment system, microbial screening is carried out in tank A, and organic pollutant degradation is carried out in tank 0;
e. Adopting Fenton advanced oxidation standard raising and deep treatment technology for discharge, to ensure that the quality of the discharged water in this project meets the requirements of the Water Pollutant Discharge Standard for Pulp and Paper Industry (GB3544-2008).
2) Paper wastewater treatment
a. The papermaking wastewater of this project contains a large amount of pulp fibers and other impurities, and the influent SS is high. Therefore, inclined mesh fiber recovery is carried out first, and then chemical coagulation sedimentation is used to remove most of the dispersed and colloidal pollutants, improving the subsequent biological treatment influent water quality;
b. After physicochemical treatment, the concentration of organic pollutants in the effluent is still high, and most of them exist in a dissolved state. Therefore, EGSB anaerobic treatment is first used to remove some organic pollutants and reduce the subsequent load of good pen treatment. The aerobic treatment adopts a two-stage A/0 system to adapt different bacterial communities to different organic concentrations, achieving the effect of segmented training and treatment, and ensuring stable and standard discharge of treated water quality;
c. A deodorization system has been set up for the odor generated by the regulating tank, EGSB anaerobic reactor, and sludge storage tank of the anaerobic treatment system in this project。