Studies On Treatment Of Papermaking Wastewater With Mixed Flocclating And Air Floating-Aerobic Biological Fluidized Bed Technology (ABFT)

The paper industry is one of important industries of our country national economy, however it brings more and more environment pollution day by day and becomes the hot spot and the focal point which the society pays attention. The paper industry uses a lot of water, it also results in more pollution. Along with the development of economy, the corporation must face the problem of short water and meterial resource. On the other hand, water pollution becomes more and more serious, now in our country, The paper industry pollution is not only the chief problem of prevention, it is also the chief problem of disposal industry waste water eligibility. The pulp waste water has the characters of abundant effluent and complicated contamination. The production crafts of some medium-scale are backward, There are no effective processing measure for the papermaking waste water, and it has the bad influence to the environment, therefore, it can obtain the ideal preventing and controlling effect by researching the economically and highly effective waste water processing craft, This need to understand fully in the paper industry production characteristic and the waste water characteristic.This article uses the flocculation-flotationt and the aerobic biological fluidized bed techology (ABFT) to dispose the pulp waste water which from the North Paper Company of Si Ping. The experiment provides the master data and the technical support for the actual project project. Finally, make technical and economical analysis for the experimental results.The North Paper Company of Si Ping uses straw for the main producers'goods. The waste water from this factory includes three parts. The concentration of mixed waste water'COD is 3566mg/L.According to the former research, it obtains the good effect by using polymerization aluminum chloride (PAC) to dispose the paper industry wastewater, the selection of coagulant aids is polyacrylamide (PAM). Carrying on the laboratory experiment through the Single Factor Rotates, under the condition of pH is 5, the optimal dosage of PAC (the Al₂O₃ content is 10.3%)is 14ml/L, and PAC(5‰) is 6ml/L, the temperature of coagulant is 20℃, the mix round time is 5min. Under the best conditions, it obtained the good effort that showed removal rate of COD from papermaking waste water about 42%.The size of mixed flocclating and air floating equipment is 3.2×1.2×1.4 (m). The dosages of PAC and PAM are according to the laboratory experiment, considered the economic agent, the pH of mixed flocclating and air floating is equal to the original water's pH (pH=7⁸).The water power resident time is 15min, the reflux ratio is 10%. The COD of original water is about 3500mg/L, after the mixed flocculating and air floating processing, the COD is 1800²000mg/L, removing rate is approximately 45%, it has provided the advantage for the following treatment of using biological method. But after some time, the removing rate of mixed flocclating and air floating equipment becomed down. This is because the granule go down the bottom of the equipment. So it is necessary to clean the equipment after some time.The section of biological treatment is six levels of aerobic biological fluidized bed technology (ABFT). After 62 day-long breed and domesticated, when the flux is 350 L/h, the disposal of the waste water by ABFT is at the steady state. On the 62nd day, the COD of which waste water from the fourth pond has achieved 229mg/L, that is lower than the national discharge standard for papermaking waste water (300 mg/L). The COD degradation efficiency of the sixth pond is very low, it has very small function for the waste water disposal, its function when design mainly is the protective function and preventing the shock loads which caused by high COD concentration of original water.Estimate the cost of waste water disposal project by the master data which from research, after the run of this disposal project, the disposal cost is 0.799Yuan per ton waste water. Contraposing other disposal project, the disposal cost is 0.799 Yuan per ton waste water, the cost of medicament is 0.20 Yuan, the runing cost of biology disposal is under 0.35 Yuan. It proved that mixed flocclating and air floating- aerobic biological fluidized bed techology is a kind of economical and effective processing craft for papermaking waste water.