Removal of Phosphorus from Water through Microbially-induced Calcium Carbonate Precipitation

CAO Jinpeng; QIU Xuan; MA Liyuan; LIU Deng

doi:10.19672/j.cnki.1003-6504.0935.23.338

Abstract：Due to human activities,excessive phosphorus emissions into water bodies are increasing,leading to eutrophica-tion.The phosphorus-induced eutrophication can directly result in deterioration of water quality and biological imbalance in aquatic ecosystems.Therefore,it is important to develop efficient and cost-effective approaches to phosphorus removal from waters.As a novel bioremediation technology,microbially-induced calcium carbonate precipitation(MICP)has been widely employed to mitigate heavy metal contamination.However,it is still unclear whether MICP is a suitable strategy for reducing phosphorus-based water eutrophication.To achieve this goal,the present study evaluated the effect of MICP using a typical ureolytic bacterium Sporosarcina pasteurii on the removal of soluble phosphate in the range of 150～400 mg/L.The results showed that the concentration of soluble phosphate quickly declined within 2 hours when MICP was initiated by Ca2+ additive.Upon the treatment of MICP,the removal extents of soluble phosphate for the systems with 150,300 and 400 mg/L reached 95.4%,87.72%and 72.05%,respectively.The resulting bio-precipitates were collected for mineralogical analyses.The data showed that phosphate was removed from solution by the adsorption of microbial calcite under low phosphorus conditions(150 and 300 mg/L).However,phosphate was mainly removed via the co-precipitation process when the initial phosphate concentration was 400 mg/L.The co-precipitated minerals were composed of hydroxyapatite and phosphorus-containing calcite.This study reveals that MICP has a great potential for removing and fixing phosphorus from water bodies.