Study On Water-Based Ink Wastewater Treatment Technology

Because of the shortage of petroleum, people in printing and packaging turned around the research and appliance of oil-based ink from water-based ink. With the development of material science, the binder of water-based ink was improved that exploits its application area, which resulted in water-based ink wastewater discharge increasing greatly. As a new kind of printing and dyeing wastewater, water-based ink wastewater which outstanding characteristic is high chemical oxygen demand, high chroma and difficultly biodegraded is still part of dyeing and finishing of textile industry. Once the wastewater enters water body, it will greatly pollute water environment that will seriously threaten human production and life and the natural ecological balance, which has attracted wide attention in the social life. In order to the request of improving environmental quality, the government drawn strick discharge standard of water-based ink wastewater, and developing economical, high efficient treatment of this wastewater has become the emphasis and hotspot of water treatment technology.This paper taking high concentration water-based ink wastewater from a corporation in Xi'an as the researching object, studied on its treatment technology via the preparation of experimental material, degradation of methylene blue—simulating water-based ink wastewater and the treatment of water-based ink wasterwater. This thesis aimed at finding out the optimum conditions of photocatalysis degrading methylene blue by Kaolin ultrafine zeolite composite photocatalyst, and establishing the economical treatment technology on water-based ink wastewater by acid precipitation, chemical flocculation, photocatalysis and biological method.The main findings were as following:(1) In allusion to the characteristic of water-based ink wastewater, we have choosed reasonable determining quota and the standard manual method, filtrated methylene blue as the simulant water-based ink wastewater and prepared Kaolin ultrafine zeolite composite photocatalyst.(2) Using L25(56) orthogonal experiment, we have discussed the effect of the light source, pH, reaction time and the concentration of H2O2, photocatalyst and methylene blue on photodegrading methylene blue. The result showed that the optimum conditions were 2 000 mg/L, 500 mg/L and 80 mg/L respectively being as the concentration of H2O2, photocatalyst and methylene blue, pH=10.00, ultraviolet disinfection lamp (20 W) irradiating 240 minutes, then the decoloration rate, the chroma and pH for methylene blue were 99.46%, 17.37, 7.58 respectively, which reached theⅠd ischarge standard of water pollutionts for dyeing and finishing of textile industry(GB 4287—92).(3) Through acid precipitation, chemical flocculation, photocatalysis and biological method, the economical treatment technology on water-based ink wastewater was established: the optimum pH value and standing time of acid precipitation was 4.36 and 12 hours respectively, the residence time of supernatant in the hydrolysis-acidification pool was 24 hours, then entering the sequencing batch reactor, the optimum dose of activated sludge was by SV30=25%, the temperature was 20±1℃,the dissolved oxygen was 9.07 mg/L and the aeration time was 8 hours, which could stablely operate half a month at least. The effluent of SBR: the pH value was between 6 and 9, the chroma was less than 40(dilution multiple method: the initial chroma was106 375), the BOD5 was less than 25 mg/L, which reached theⅠdischarge standard of water pollutionts for dyeing and finishing of textile industry. The CODcr was less than 500 mg/L (the initial was 31 040 mg/L), which was close to theⅡdischarge standard of water pollutionts for dyeing and finishing of textile industry. The SS and turbidity of supernatant were not detected. The optimum condition not only saved energy sources of traditional biological method but also the indexs of effluent reached or exceeded theⅢd ischarge standard of water pollutionts for dyeing and finishing of textile industry.