The Application Research Of Perchlorate Removal From Drinking Water Sources Using Slow-release Electron Donor Polymers

Perchlorate is a kind of persistent endocrine disruption poluttants and it inhibits iodineuptake in the thyroid gland causing the reduced production of thyroid hormones, which hasbeen detected in groundwater, surface water and even drinking water, and has attach highlyconcerns to researchers home and abroad. In the technologies of perchlorate degradation,biological approaches for treating perchlorate have proven to be effective and economicallyattractive, and perchlorate was degraded to chloride ion which is nontoxic and harmless byanaerobic bacteria. The reduction process needs to accept electron from some inorganic ororganic electron donor, but electron donor are extremely insufficient in actual groundwaterand need to dose some electron donor to reaction system. Looking for the cheap and highlyactivity slow-releasing material that can be used as electron donor and biofilm carrier is thekey to the safe and efficient of perchlorate biodegradation.The primary objective of this research was to study the process of ativated sludgedomestication, and to demonstrate the feasibility of biodegradation take BDPs as carbonsource and biofilm carrier to remove perchlorate in affected drinking water. This paperincludes following contents and conclusions:1. There are three kinds of biodegradation material of PVA, PCL, PBS were preparationand used to perchlorate biodegradation, finally select PBS as the electronic donor and biofilmcarrier for further research of perchlorate biodegradation.2. Temperature has a certain influence on perchlorate degradation rate in PBS biofilmsystem and the optimal biodegradation temperature is30℃, perchlorate degradation rate was0.2857mg/L·h; PBS biofilm can endure some extent shock load of influent pH, the removaleffect were better under neutral or slightly alkaline environment; The perchlorate degradationrate was1.57times while DO was1.4mg/L than in saturated DO conditions; PBS biofilm canendure a certain hydraulic shear force; At some extend, perchlorate degradation rate willimprove as the increase of PBS dosage,2mg/L perchlorate can be reduced to detection limitsin5h while PBS was60g.3. In PBS biofilm reaction system, the realationship of temperature and perchloratedegradation rate constant can be described by Arrhenius equation and fit ln k0.6546.81/T; Results shown that there is a linear relationship between perchloratedegradation rate and PBS dosage; At some extend, the degradation rate constant was reducedas inflow perchlorate increase, and it fit first order kinetics.4. To observe the biofilm on PBS surface after biofilm reach maturity and the scanpicture of PBS material surface and the biofilm on PBS surface show that the PBS surfaceemerged some crowded pores after biofilm formation, the space will further increase the areaof degradation bacterium growth and increase the perchlorate degradation rate. Perchloratedegrading bacteria can easily growth on PBS surface and formed dense and structured biofilmto remove perchlorate steadily.5. Static experiment shown that PBS can be decomposed to release small organicmolecules and provide carbon source for degradation bacterium only in the microbial function.The number of suspended bacteria were rare in reaction solution after biofilm reach maturity,and the inflow perchlorate were mainly reduced by biofilm.6. The biofilm on PBS surface in packed bed were relatively loose and caused it waseasily affected by inflow shock load. The inflow perchlorate could be removed effectively in acertain influent flow. In the running processes of packed bed, HRT was increased from4h to2h,1h,2mg/L perchlorate can be reduced to detection limits, and the perchloratedegradation was not ideal after further improved to0.5h.7. The perchlorate degradation rate was0.1901mg/L·h by PBS granule in packed bedand the degradation rate was0.2857mg/L·h in static experiment, the biofilm morphology wasobserved by SEM and find the biofilm were relatively loose, this is because the conditions ofbiofilm gowth were different and made their composition of microbes differently and causedthe differences of perchlorate removal effect.