Study On The Utilization Of Rainwater By Flocculation-Ultrafiltration Combined Process

With the vigorous development of cities,the problem of lack of water resources has gradually emerged.As unconventional water,rainwater is the strongest supply in urban life.The ultrafiltration process is often applied to the treatment of drinking water and sewage,but there is not much research on the use of the ultrafiltration process to treat rainwater.It is of great significance to treat rainwater reasonably and effectively to make it reach the standard of rainwater reuse and fully realize the utilization of rainwater.This paper proves through experiments that the combined flocculation-ultrafiltration process has certain pollutant removal capacity for early rainwater and later rainwater,and can meet the urban miscellaneous water standards;through calculation,it is proved that the combined flocculation-ultrafiltration process can increase the potential of rainwater resources to a greater extent Development and utilization of rainwater.And the direct running cost of the combined process is low,which is convenient for popularization and operation.Therefore,the research of this topic can play a certain reference role for the saving of water resources and the utilization of rain water resources.Based on the measured rainfall data in Yubei District of Chongqing,this paper uses conventional flocculation,direct ultrafiltration,and flocculation-ultrafiltration combined technology to simulate the early rain and the later rain through water distribution to study the treatment of rainwater.Compare the conventional water quality of the raw water and the effluent to determine whether the process of the rainwater treatment process meets the urban rainwater reuse standard.At the same time,according to the rainfall information of the area and the land use type and area and other relevant data,the rain water resources potentials of the high water year,the flat water year and the low water year are estimated respectively,and combined with the flocculation-ultrafiltration combined process for the treatment of rain water As a result,the probability that the rainwater treated by the process meets the rainwater reuse standard is calculated,so as to re-estimate the actual potential of the area.Based on the relevant tests and calculation results,the analysis and evaluation of the rainwater resource utilization,and the following conclusions are drawn:The optimal parameters for the initial rainwater treatment in the conventional flocculation process are rapid stirring for 1min,slow stirring for 6min,flocculant dosage of 6mg/L,and precipitation time of 10min to 20min;the optimal parameters for the later treatment of rainwater are rapid stirring for 1min,Slow stirring for 3min,the dosage of flocculant is 9mg/L,and the precipitation time is 20min.The best removal of water quality index is turbidity and total p Hosp Horus.The turbidity removal rate is above 86%,and the total p Hosp Horus removal rate is above 72%.The direct ultrafiltration process has a very good effect on removing turbidity,which is basically stable above 99%,and the turbidity removal ability is not much related to the original concentration of raw water.The removal rates of COD,UV₂₅₄,ammonia nitrogen and total phosphorus are all around 20%.The removal effect of the flocculation-ultrafiltration process on total nitrogen and ammonia nitrogen is equivalent to that of direct ultrafiltration,and the removal rate is about 23%and 35%,respectively.The removal effect of total phosphorus and UV₂₅₄is significantly higher than that of direct ultrafiltration,which is about 75%and 65%,respectively.And compared with direct ultrafiltration,the flocculation-ultrafiltration process significantly improves membrane fouling.The actual potential of rain water resources(PI=4mm)in Yubei District of Chongqing City is 2272.04×10⁵m³,2042.75×10⁵m³,and 1835.01×10⁵m³in high water year,normal water year,and low water year;In general,the actual potential of rainwater resources in the typical year of the area has increased by 55.5%overall.