Performance Of Perchlorate Reducing Granular Sludge Under Different Operation Strategies And Fe-HA Complexs

Perchlorate（ClO₄^-）is a persistent toxic pollutant which causes serious environmental problems.Thus,the ClO₄^-effective removal is widely concerned.Microorganisms in granules can completely convert ClO₄^-into Cl^-,which has the advantages of low cost,no secondary pollution and high removal efficiency.However,there are still problems such as slow degradation rate and limited perchlorate loading rate（PLR）of tolerance.Based on the successful cultivation of the perchlorate reducing granular sludge（PRGS）,the maximum PLR of tolerance with the granules was discussed under different PLR increase strategies;the effect of immobilization of iron-humic acid（Fe-HA）complexs in granules on the PLR of tolerance was studied.With denitrifying granular sludge as the inoculated sludge,the method of decreasing nitrate and increasing ClO₄^-concentration was adopted to cultivate the PRGS.After 50days of cultivation,the ClO₄^-removal efficiency was over 90%.The maximum PLR of tolerance with granules was studied by the different PLR increase strategies.These results showed that the maximum PLR of tolerance was 9.90g·（L·d）^-1 under the slow increasing strategy;the maximum PLR of tolerance was 10.67g·（L·d）^-1 under the rapid increasing strategy.The extracellular polymeric substance secreted under the rapid increasing strategy was 1.9 times higher than that under the slow increasing strategy,resulting in the accumulation of granules.Thus,the rapid increasing strategy has higher the maximum PLR.The maximum PLR of tolerance with granules was studied by the immobilization of Fe-HA complexs in granules.These results showed that the maximum PLR of tolerance was 10.29 g·（L·d）^-1 under the non-immobilization of Fe-HA complexs in granules;the maximum PLR of tolerance was 11.83 g·（L·d）^-1 under the immobilization of Fe-HA complexs in granules.Fe-HA complexs can promote the enrichment of quinone reducing bacteria in granules,resulting in the increase of the maximum PLR of tolerance with granules.