Studies On The Treatment And Resource Utilization For Modified Starch Wastewater

China is a traditional agricultural country with a promising modified starch processing industry,having varieties of modified starch products.Large amount of modified starch wastewater which mainly contains high concentrate of organic matter even toxic and harmful substances will be produced in the process of modified starch products processing.Modified starch wastewater has characteristics of high values of COD,BOD₅ and SS,thus leading to serious pollution.Presently,modified starch wastewater is treated by conventional biological treatment methods which have some disadvantages and limitations such as expensive investment,complex equipment operation management and weak environmental impact resistance etc.The research adopted the coagulation sedimentation method and the vibration membrane filtration system combined with ultrafiltration and reverse osmosis membranes respectively to treat modified starch wastewater,strengthening the treatment effect and achieving dual purposes of water recycling and resource utilization.Results showed that PAC was proven to be an effective material for coagulation process to treat modified starch wastewater.In normal temperature,PAC was capable to remove TSS up to 99.22%using the recommended treatment conditions of dosage,initial pH,settling time,fast stirring and slow stirring speed at 400 mg·L^-1,pH 7,25 min,200 rpm and50 rpm,respectively.Meanwhile,the removal rate of COD was 60.28%and biogas production of sludge was 226.63 mL·g^-1VS,so as to realize the recycling of energy and create economic benefits.Modified starch wastewater was treated by the vibration membrane system combined with“UF-RO”membranes and the results showed that in normal temperature,each vibration frequency had correspondence amplitude and the shear rate induced was two times higher than traditional cross-flow system,thus better controlling membrane fouling phenomenon.At the optimal operating amplitude of 12 mm,and the optimal operating pressure of 0.2 MPa and 1.2 MPa respectively,the removal rates of COD_Cr,TP were 99.18%and 99.83%.Moreover,the effluent could be reused which fully meeting the"urban recycling landscape and environmental water quality standards"?GB/T18921-2002?.The total phosphorus content in the two levels of concentrate were as high as 142.57 mg·L^-1 and 180.48mg·L^-1 which could be extracted and recycled through certain processing methods,realizing the utilization of modified starch wastewater.This two treatment processes on the one hand,could treat modified starch wastewater effectively,breaking through the limitations of traditional biological treatment as well as obtaining good application and popularization value.On the other hand,could recycle effective resource in modified starch wastewater,achieving energy conservation and economic benefits as well as providing theory basis for other industrial wastewater.