Study On Enhanced Treatment Of Molasses Alcohol Anaerobic Effluent

Molasses alcohol anaerobic effluent contains plenty of toxic organic compounds, such as long-chain hydrocarbon, olefin, benzene and form phenols, which leads to poor biodegradability. In order to ensure that wastewater could meet the discharge standard, pretreatment of high density and refractory organic compounds is indispensable. Therefore, experiments were conducted to study the role of Fenton reaction and micro-electrolysis in removing COD and decreasing toxicity and improving the biodegradability.Fenton treatment was preliminarily employed to investigate the mechanisms of affecting factors. Based on both of the removal performance and the operating costs, optimal reaction condition was proposed as follows:m(H2O2):m(Fe2+)=1:1, H2O2 dosage2.13g/L,30min at initial pH=6, and the treated wastewater regulated by calcium hydroxide. Under these conditions, the COD removal is 77%, color removal is 86% and the degradability of Fenton effluent can be enhanced to 0.24 (BOD5/COD), bio-toxity decreased to non-toxic from strong toxicity. Furthermore, organic compounds analyzed by GC-MS method are mainly non-toxic complex organics. Operation cost was 16.33 RMB/t considering reagent cost.Due to costliness of H2O2, further experiment of iron-carbon electrolysis was pretreated by iron-carbon micro-electrolysis and the effect of the influent pH value, iron to carbon ratio, and aeration time on the COD removal efficiency was mainly discussed. Operating at m (iron):m(carbon)=1:1, aeration time 5.5 hour at initial pH=3, and calcium hydroxide regulated the treated wastewater, great preformance achieved:71% of COD was removed and 89% of chromaticity was decreased. Furthermore, the degradability of iron-carbon electrolysis effluent can be increased from 0.14 to 0.35 and bio-toxity decreased to non-toxic. The iron-carbon electrolysis process is much preferred regarding the COD removal efficiency and biodegradability, including the cost of reagent is 6.6 RMB/t.Response Surface Methodology model was set up for Fenton reaction on anaerobic effluent treatment, taking COD removal rate as the response value, and F=32.89 and p=0.0006 shows the model is reliable. The results show that it is a reliable model for their interactions and single factors of initial pH, hydrogen peroxide dosage and H2O2/Fe2+ ratio have a significant effect on the model, which in order as initial pH, m(H2O2):m(Fe+), and H2O2 dosage. The model results have a better prediction.