Effect Of Powdered Activated Carbon Adsorption On UF Membrane Fouling Caused By EOM

With the rapid development of industrialization and urbanization, the eutrophi-cation of natural water became worse. The eutrophication of natural water can lead tothe crazy growth of algae. Algae cells and microcystin、extracellular organic matter(EOM) secreted by algae cells will effect the security of potable water. Due to a seriesof merits, UF membrane is applicated in algal-rich water treatment. However, thepromise of UF technology will be limited by the problem of membrane fouling.Pretreatments are co-mmon methods to control membrane fouling.This paper adopted PAC-UF hybird process as the treatment for water polluted byEOM. We will investigate the effect of PAC on membrane fouling and discuss whetherPAC can alleviate membrane fouling. Later, discussing the mechanism of membranefouling. Through the optimal experiments, these results can provide supports for therunning and manage of the waterworks in which PAC-UF technology is used, when theseasonal algae bloom occurs.First, the adsorption effects of EOM by different types of power activated carbonwere studied. Experiments’ results showed that the adsorption effects are different whendifferent types of PAC were used. Effect of coconut PAC was better than others. Whenthe concentration was60mg/l, DOC and UV254removal efficiency were better,. So60mg/l was the best dosage.Second, the adsorption characteristics of PAC and the characteristics of membranewere investigated. It found that PAC mainly adsorb MW<10kDa、hydrophilic、humic-like organic matters; UF mainly intercept MW>100kDa、hydrophilic、protein-likeorganic matters.Last, this paper applied PAC-UF to treat EOM-pollutant water. Comparing fluxcurve、change of resistance to evaluate the influence of factors on the PAC-UF process.The results showed that adding PAC to UF system could not alleviate membrane fouling.However, the irreversible fouling weakened. The dosage of PAC had a little effect onthe membrane flux; when pH=7, the performance of PAC-UF was best; even if theconcentration of HA reached to double of EOM, the change of flux was not evident; theflux declined seriously when TMP increased by dead-end filtration; within certain limits,adding Ca2+would improve the flux of PAC-UF. Final, three mathematical models were used to fit the processes of D-UF andPAC-UF. The similar results were obtained that the coefficient of correlation of cakefiltration was higher than others, so I drought a conclusion that the cake filtration wasthe main mechanism of fouling during the paper.