Characteristics Of Iron Dissimilation Reduction Of Iron Rich Soils In Constructed Wetland

This paper selected the common lateritic red soil in South China as the research objects. Sequence batch experiments and destructive sampling system were applied to study the alienation reduction characteristics of Fe(III) in lateritic red soil with glucose, sodium acetate and starch as the electron donors respectively, as well as the role of the accelerant AQS and temperature to the reaction. The lateritic red soil and their microbial morphology were observed by High throughput sequencing. Finally, the analysis of the iron dissimilation reduction of lateritic red soil in the dynamic system was carried out by the simulation of the soil column system.Results showed that the Fe alienation reduction could be observed in different lateritic red soil under the anaerobic system of glucose, sodium acetate and starch. However, ferrous iron productions in the 3 systems were quite different, with starch system to be the highest, up to 479.28 mg/L and the overall ferrous iron productions in lateritic red soil 1 were higher than those in lateritic red soil 2. AQS had obvious facilitating effects on Fe alienation reduction in lateritic red soil 1 and lateritic red soil 2 under starch system with different pathways, in which it enables more ferric iron to reduce into ferrous iron in lateritic red soil 1 and the ferrous iron production was up to 1101.36 mg/L while in lateritic red soil 2 it promotes the reduction rate. Temperature also influenced obviously the alienation reduction rate in lateritic red soil, with little difference between 25℃ and 30℃ but the reaction slowed down significantly below 20℃.In lateritic red soil, the bacteria which promote the reduction of the iron dissimilation are mainly Clostridium, Ruminococcus, Anaerolinea, Geobacter and Anaeromyxobacter. In the dynamic experiment of lateritic red soil system, the rate of the organic load and the high hydraulic load were decreased and the iron dissolution rate was high. The amount of iron dissolved in lateritic red soil decreased with the increase of the height. The increase of small particles on the surface of Lateritic red soil in the reduction of iron dissimilation.