Research On The Treating Methods Of Areca Wastewater

With the enhancement of industrialization, industrial wastewater increased per year. Nowadays research on wastewater treatment technology is becoming deeper and deeper since society pays more attention to environmental protection. However, no one has investigated the treatment process of areca wastewater in China, which due to it is a typical persistent organic wastewater. The organic wastewater has the quality of high concentration of pollutants, nonbiodegradable and nonbiodegradable. So the main process to deal with areca wastewater is physical or chemical pretreatment and biochemical treatment at present. Pretreatment is useful to change the biochemical treatment of refractory organic matter, lift biotoxicity, enhance the biodegradability of wastewater, which will shorten reaction time, increase treatment effect and decrease operation cost in practice. Besides, system with pretreatment is stable, easy to control and won’t bring secondary pollutant to environment.Iron-carbon micro-electrolysis has wide application scope, but its treatment effect of refractory organic matter is not good and the effluent can’t come up to the standard. Fenton reagent has great oxidizing capacity which can oxidize organic matters to CO2and H2O. Fenton reagent has very good treatment effect but its disadvantage is that the cost is too high. Coagulating sedimentation, as a commonly known pretreatment process, could transfer the organic matter in wastewater by chemical and physical processes. Coagulating sedimentation has a fair treatment effect and its mix-wise use with other treatment process is common.This paper investigated the combination treatment process of the three mentioned process, which is called iron-carbon micro-electrolysis-Fenton-A/O and Coagulating-Fenton oxidation process。Iron-carbon micro-electrolysis has the advantage of wide application, using the waste iron fillings and Iron shavings for raw materials, so it has the significance of making of waste circularly. But the shortcoming is too difficult to deal with refractory organics.This research uses the areca wastewater from Hunan Youwen Co.Ltd. to investigate the main components of areca and areca wastewater and the mechanism, the influence factors and relative merits of iron-carbon micro-electrolysis, Fenton oxidation and coagulating sedimentation.The optimum reaction condition of Iron-carbon micro-electrolysis and Fenton reaction is investigated by single factor experiment. Besides, the best reaction condition is that Fe/C=1:1, pH=3, reaction time is3h, the addition amount of H2O2is3%(volume ratio), initial pH of Fenton is3. GC-MS technology was used to analyze and compare the components of raw wastewater and effluent. The result of the biochemical treatment of effluent under the optimum reaction condition showed that the biodegradability increased from0.094to0.37. After one cycle in A/O system, COD decreased from791mg/L to247mg/L which means that COD removal efficiency of micro-electrolysis-Fenton-A/O process was96.22%and chroma removal efficiency was98.8%, respectively.This research also analyzed coagulating-Fenton technology using five common coagulants to treat areca wastewater and investigated the removal efficiency of COD and chroma of coagulation process under different conditions with different addition amount and pH. According to the COD removal efficiency, the descending order is polymeric coagulants>inorganic aluminates>inorganic malysite; according to the sedimentation rate, the descending order is polymeric coagulants<inorganic aluminates<inorganic malysite; Fenton oxidation reaction, which used optimal coagulant and pH=7.5, was used to treat wastewater. The result showed that when the addition amount of H2O2was2mL/L,pH=3,n(Fe2+):n(H2O2)=1:10and reaction time was30min, the treatment efficiency was the best.