The Adsorption And Hydrolysis Of Dye Wastewater By Anaerobic Sludge

With the rapid development of dye industry in the world, dye wastewater due toits good stability, difficult to degradation and strong toxicity characteristics hasbecome the research focus in recent years in our country and abroad. Because of theproblems like low rate of CODcr removal, dye removal, decolorization and wil causesecondary pollution during the physical and chemical methods, most researchersfocus their research on biological treatment. This study focuses on proposing a newtechnology of dye processing——high concentration of anaerobic sludge adsorbedand hydrolyzed dye wastewater. There were a series of in-depth studies researched onhigh concentration of anaerobic sludge adsorbed and hydrolyzed dye wastewater.This paper was doing research from the sludge cultivation, anaerobic sludgedomesticated, static adsorption experiment and dynamic adsorption and hydrolysisexperiment four aspects.The anaerobic reactor was used for anaerobic sludge cultivation. After45days,the concentration of sludge was33490mg/L. The ORP value was stability between-200mV and-400mV, the DO value was already unger0.3mg/L and large anaerobicsludge floc appeared, it was considered the cultivation of anaerobic sludge wassuccessful. After the successful cultivation of high concentration anaerobic sludge, westarted using methylene blue, methyl orange and malachite green to domesticate thehigh concentration anaerobic sludge. The dosing ratio of nutrients duringdomestication in accordance with COD：N：P=200：5：1. The domestication processwas count in cycle. There are7days per cycle. The domestication process wasdivided into6cycles. At the end of the domestication, When the influent CODcrvalue was about2400mg/L,the effluent CODcr value of methyl orange was about240mg/L and the CODcr removal rate was steady at more than90%. When theinfluent effluent concentration of methyl orange was about400mg/L, the effluentconcentration of methyl orange was about3.8mg/L, the methyl orange removal ratewas steady at more than99%. When the influent color of methyl orange was about16000, the effluent color of methyl orange was about100, the color removal rate wassteady at more than99.3%. When the influent CODcr value was about2400mg/L, theeffluent CODcr value of methylene blue was about60mg/L and the CODcr removalrate was steady at more than97%. When the influent effluent concentration ofmethylene blue was about400mg/L, the effluent concentration of methylene blue was about1.2mg/L, the methylene blue removal rate was steady at more than99.5%.When the influent color of methylene blue was about24000, the effluent color ofmethylene blue was about150, the color removal rate was steady at more than99.3%.When the influent CODcr value was about2400mg/L, the effluent CODcr value ofmalachite was about90mg/L and the CODcr removal rate was steady at more than96%. When the influent effluent concentration of malachite was about400mg/L, theeffluent concentration of malachite was about3.2mg/L, the malachite removal ratewas steady at more than99.1%. When the influent color of malachite was about8600,the effluent color of malachite was about40, the color removal rate was steady atmore than99.5%.During the static adsorption experiments, the influences of sludge concentration,adsorption reaction time, concentrations of dyes and dye types on the static adsorptionexperiments were studied. The results showed that the concentration of anaerobicsludge has a greater impact on the effluent concentration of dye and dye removal. Thehigher the sludge concentration was, the adsorption rate was faster, the adsorptionequilibrium time was shorter, the dye removal rate was higher. Influent concentrationof dye and dye types also had an impact on the adsorption reaction, but the impactwas relatively small. The results of the static adsorption experiment showed that whenthe influent concentration of the dye was400mg/L, the MLSS was18620mg/L andthe adsorption reaction time was30min, the best results could be achieved. In thiscase, the removal rates of methylene blue, methyl orange and malachite were98.59%,98.09%and98.51%.During the dynamic adsorption and hydrolysis experiments, according to thestatic adsorption experiment fixed adsorption time as30min. The influences of sludgefeflux ratio, anaerobic hydrolysis time, influent concentrations of dyes and influentdye types on the dynamic adsorption experiments were studied. The results showedthat the sludge reflux ratio and anaerobic sludge hydrolysis time has a greater impacton the effect of anaerobic hydrolysis. The types of dyes followed. When the influentconcentration of dye was lower than400mg/L, the impact of influent concentration ofdye could not be considered. The results of the dynamic adsorption experimentshowed that when the adsorption time was30min, the sludge reflux ratio was400%and the anaerobic hydrolysis time was4h, the best results could be achieved. At thistime, the CODcr removal rate was steady at more than90%, the removal rate ofmethylene blue, methyl orange and malachite were were about99.61%,99.06%and 98.64%.During the static adsorption experiment and dynamic adsorption experiment, thevariations of pH value were the same. As the reaction proceeds, pH value decreases.This was caused by anaerobic hydrolysis produce acid.