微生物生长繁殖条件下土壤污染物的输移降解模型

Modeling the migration and degradation of soil contaminants by considering microbe propagation

准确模拟和预测污染物在土壤中的输移降解过程对污染控制、环境保护和生态修复等均具有重要的意义,但目前的模型或将污染物的微生物降解过程简化为0阶或1阶降解过程而降低了模型模拟预测精度,或注重于对某一种或某一类污染物的微生物降解过程的描述而不具有通用性。根据微生物的生长动力学和降解动力学机理,本研究在传统的水、热和溶质运移耦合模型的基础上添加微生物降解模块来构建新的模型。该模型综合考虑污染物质在固、液、气三相中的输移降解过程、逐级降解过程和多种微生物共同作用下的降解过程,并综合考虑了微生物生长繁殖和多种限制因子对污染物降解过程的影响,同时保留了现有通用模型中常用的0级和1级降解过程,具有较强的实用性和通用性。模拟分析结果表明:土壤中的微生物降解作用对污染物质在土壤中的输移降解过程影响明显。

Accurately modeling and predicting the migration and degradation of contaminants in unsaturated soil have fatal research significance for pollution controlling,environmental protection and ecological restoration.However,most of the current numerical models either simplify the microbial degradation process to a zero-or first-order degradation process and decrease the modeling accuracy,or focus on describing one kind of microbial degradation process and cannot be used as an universal way.To make the numerical model with high modeling efficiency and universal applicability,microbial degradation module,incorporating the effects of microbe propagation,is coupled into the traditional water flow,heat transfer and solute transport model in this research.The migration and degradation of contaminants in solid phase,liquid phase and gaseous phase,sequential decay processes,and degradation under the interaction of multiple microbes are intergraded into the new model.Besides,the effects of microbe propagation and multiple inhibition factors on contaminant degradation are considered in the new model.Furthermore,the zero-and first-order degradation processes in the traditional model are also kept in the new model.Thus,the new model is with both good practicality and applicability.The modeling comparison illustrates that the bio-degradation in unsaturated soil affects solutes transport and can not be ignored.