Treatment Of Industrial Wastewater Containing Methanol Using UASB

This topic derives from the project of high concentration methanol-containingester wastewater treatment from fine chemical industry of Jiangsu Province. Thefactory mainly produces two kinds of wastewater: one kind is alcohol-containingesters wastewater (mainly wastewater); another kind is formaldehyde-containingesters wastewater (secondary wastewater). According to the character of thewastewater，first of all was to adopt a upflow anaerobic sludge blanket reactor(UASB)to treatment high concentration methanol-containing ester wastewater, which mainlyfocused on anaerobic digestion characteristics, the operation stability，ability and theinfluence factors of UASB treating high concentration methanol-containing esterwastewater; and then, considering the characteristics and discharge(Wastewater closerow) of wastewater and other specific conditions, the present also studied the effect offormaldehyde on the UASB process methanol-containing esters wastewater.Test results of treating methanol-containing ester wastewater by UASB show thatunder the condition of volume loading rate(VLR)1.32kgCOD/(m3·d) and hydraulicretention time (HRT)4d，reflux ratio90:1,Influent COD concentration5280mg/L，steady operation was achieved with more than95%of total COD removed and theCOD in effluent was always between100～200mg/L.Influent COD concentration，HRT and NaHCO3dosage are determined to be key controlling factors of UASBstart-up in this paper.The tested system has good performance with high removal ofester when HRT extends to4d.Meanwhile，NaHCO3dosage decreasing to600mg/Lcan still ensure the pH value of effluent maintain at7.3～7.6.No volatile fatty acids(VFA) accumulation observed in the experiment and this result shows that thedegradation of methanol experiences no acidification phase.This paper is valuable forindustrial treatment of high concentration methanol-containing ester wastewater.Toxicity effect of formaldehyde on the performance of treating methanol-containing ester wastewater.Test results of treating formaldehyde-containing ester wastewater by UASBshow that under the condition of HRT4d，reflux ratio90:1，comparing volumeloading rate to formaldehyde loading rate in the early stage，the former to the impactof the system is significantly greater than the latter；When formaldehyde load ratemore than1.056kg FA/(m3·d)，improving the system load and load capacity ascensionformaldehyde，compared to the impact of the system to significantly greater than theformer； When formaldehyde load rate increases to3.303kg FA/(m3·d)， feedformaldehyde concentration is13.212g/L，total COD reductions fall to86.9%，thedegradation of formaldehyde without influence，and the reductions of methanol havefallen to39.43%，which explains the toxicity of formaldehyde of methanol anaerobicdegradation shows a strong inhibition. It is observed， under the condition offormaldehyde loading rate3.68kg FA/(m3·d) and HRT4d，over99%formaldehydecould be degraded when the COD reductions are only about77.24%of the controland no methanol be degraded.