Treatment Of Printing And Dyeing Wastewater By Biofilm Reactor

Printing and dyeing industry is a main drainage department in our country, this kind of wastewater with great capacity, high-color and complex component. Dye exhaust into the water to reduce the diaphaneity, break the ecosystem and cause the disease. At present the biological method was used mainly to process the printing and dyeing wastewater, and the biofilm reactor is the best processes method in it.In this paper, the activated carbon was used as the adsorption carrier, and the Kingella H was used as the main bacteria, the characteristic of the bacterium adsorption,the condition of the reactor movement,the dynamics of the substrate removed and the biomembrane growth,the contrast of the processing simulation wastewater and actual wastewater were studied. And obtained the results as following:(1) In the studied of the bacterium adsorption characteristic, investigated the influence of suspending bacterium concentration,liquid ionic strength,liquid pH value and temperature on the fixed biomass. The result indicated that, along with the suspending bacterium concentration increase; the fixed biomass on the activated carbon also increases and gradually tends to a stable value. The fixed biomass and liquid ionic strength become the direct proportion, the increment shows distinctness special within the scope of NaCl for 0.01⁰.20 mol/ L. When the liquid pH value is 6, the fixed biomass is most, achieve 28.9μg/cm2. The best temperature is 35℃.The kinetics research indicated that, the behavior of Kingella H bacterium adsorption on the activated carbon follow the first-order reversible reaction kinetics. After determines, the adsorption kinetics equation is: 1/B = 1.4697(1/t)+0.025.(2) Using the Kingella H strain to form biomembrane on activated carbon to establish the biofilm reactor. The influences of carbon source concentration,nitrogen source concentration,dye concentration,pH value,the temperature of enter water and aeration amount on the decolorization of biofilm reactor to crystal violet (CV) were analyzed. And obtained the order of influence factor through the orthogonal experiment: processing time>the temperature of enter water>carbon source concentration>nitrogen source concentration>pH value> dye concentration. The result indicated that, the normal operation of reactor needs the lower concentration of carbon source, nitrogen source, and the processing result was perfect. CV has the suppression to the biomembrane, but the reactor can still keep the decolorization rate above 97% when the CV concerntration is 500mg/L. The best operating conditions as following: the pH value is 7, the temperature is 35℃, and the aeration amount is 180L/min.(3) Taked the mass balance of substrate as the foundation, studied the substrate remove and the biomembrane growth dynamics, obtained the dynamics model, the CV remove dynamics model is: ; the general biomembrane growth dynamics model is: because of the CV has the suppression to the biomembrane, introduced the substrate suppression constant K IS, obtained the suppression type dynamics model is: At the same time determined the dynamics parameter: the biggest biomembrane ratio rate(μ_max) is 0.0287d^-1; the biomembrane production rate coefficient obeys equation y=129.59x^-1.1121; average biomembrane thickness( d|-) is 79.42μm; biomembrane average dry density(ρ) is 1.028×10⁶g/m³.(4) Finally, under the best operating conditions, applied this biofilm reactor, contrasted the processing results of the CV simulation wastewater and the actual printing wastewater, the simulation wastewater decolorize rate is above 95%, decrease ratio of CODCr is above 90%; the actual wastewater decolorize rate is 78%⁹2%, CODCr decrease ratio is 76%⁹0%. From these results, can find this biofilm reactor have the better application foreground, and has the value to further enlargement research.