The Research On The Function For Immobilized Biocatalyst To Strengthen Biological Treatment Of Printing And Dyeing Wastewater

The main pollutants in the printing and dyeing wastewater are non-biodegradable dyes and additives which are hazardous materials. According to the current situation of dyeing wastewater treatment, there is no substantive technology breakthrough despite years of efforts to achieve a series of practical technology solving a lot of problems. Especially, the unreasonable product structure and layout make the wastewater hard to be treated.Biological method is the commonly used method in printing and dyeing wastewater treatment. This kind of wastewater contains a lot of non-biodegradable, toxic and hazardous substances, reducing microbial activity. And the serious fluctuation of the printing and dyeing wastewater will have an effect on the biochemical treatment efficiency, leading to unstable effluent quality. What’s more, the biochemical treatment efficiency of the system running years decreases with the lower microbial activity and insufficient aeration rate. Nowadays, low biochemical efficiency has become a common concern of printing and dyeing wastewater biological treatment. It makes the effluent fail to meet the requirements of discharging, so it is not rare to see water pollutions. Therefore, it is of socially importance and practical use to explore an economical and effective new technology.This paper selected Immobilized Biocatalyst (IBC) to strengthen the printing and dyeing wastewater biological treatment in the ABR and BAF reactors. It investigates the biological treatment efficiency and discusses the strengthening mechanism. It carries out by a engineering verification test in a printing and dyeing factory. The results are as follows:(1) IBC is used for the treatment of dyeing wastewater in the ABR reactor, and the experimental results show that addition of IBC can achieve the objective of strengthenning treatment of printing and dyeing wastewater in ABR. COD and color removal rates increase by8.2%and11.1%respectively. Anaerobic sludge microbial activity is also raised largely. After adding IBC, the mean VSS/SS rises from0.349to0.447. Extracellular polymers (ECP) of compartment1,2,3increase from550,484,424μg/mg to766,692,648μg/mg respectively while coenzyme F420from724,616,3004μg/gVSS to899,863,5431μg/g VSS.(2) IBC is used for the treatment of dyeing wastewater in the BAF reactor, and the results indicate that dosing of IBC can achieve the objective of strengthenning treatment of printing and dyeing wastewater in ABR. COD, ammonia nitrogen and the aniline removal rates are increased by14.5%,6.9%,21.8%. Simutaneously, the number and microbial activity of microorganisms in the BAF ceramic have a lot of growth. After adding IBC, the number of micro-organisms, extracellular polymers (ECP) and dehydrogenase activity (DHA) have been risen from7.9×106/cm3,170.1μg/mg,8.9μg/(mg·L) to11.1×106/cm3,242.6μg/mg,11.1μg/(mg·L).(3) IBC is used in a engineering verification test of a printing and dyeing factory, and the results show that in the actual printing and dyeing wastewater projects, addition of IBC also can achieve biological treatment enhancement. In the ABR pilot experiment, COD, chroma removal rate of the test group are36%,65.3%compared to the control group29.9%,57.1%respectively. The removal rate of COD and aniline in BAF increase by8.0%and15.7%respectively.(4) Small-scale and pilot test results indicate that changes of each indices appear a similar trend. In the beginning of the dosing, there is a little change. Then it turns to be stable after a process of rapid change. However, the changing time is not exactly the same. This may demonstrates that the function of biological systems is influenced by a variety of micro-organisms, but each of the microorganisms has different ability to adapt to the environment.(5) According to the study on properties of sludge and ceramic of ABR and BAF, it can be seen that the number and microbial activity of microorganisms are increased, which means IBC enhances biological treatment of printing and dyeing wastewater. It promotes the decomposition of organics, thereby increasing the COD removal efficiency.