改良雨水生物滞留系统截留微塑料效果及影响因素探究

Investigation on removal effect of microplastics and influencing factors of modified rainwater bioretention system

选取聚乙烯(PE,疏水)和聚苯乙烯乳胶微球(PS,亲水)两种使用广泛且在水环境中频繁检出的微塑料为代表,对基质为90%砂土+10%给水厂污泥的雨水生物滞留系统在不同水力停留时间、离子强度、pH值和阳离子类型条件下截留微塑料的效果进行了研究。结果表明,当进水中两种微塑料的丰度分别为5.0×10^(4),5.3×10^(4)个/L、HRT为10 min时,微塑料在改良雨水生物滞留系统中开始穿透及完全穿透时间较传统雨水生物滞留系统均明显后移。在改良雨水生物滞留系统中,HRT由10 min提升至30 min后,聚乙烯开始穿透从90 min(9 FVs)后移至360 min(12 FVs),聚苯乙烯乳胶微球开始穿透从40 min(4 FVs)后移至240 min(8 FVs);高离子强度时(50.0 mmol/L)系统对微塑料的截留能力更强;pH及阳离子类型对微塑料的截留效果无明显影响。

Polyethylene(hydrophobic)and polystyrene latex microspheres(hydrophilic),two kinds of microplastics widely used and frequently detected in water environment,were selected as representatives.The effect of the rainwater bioretention system consisting of 90%sandy soil and 10%feedwater sludge under different hydraulic retention time,ionic strength,pH and cation type was studied.The results showed that when the abundance of two kinds of microplastics in the water was 5.0×10^(4),5.3×10^(4) items/L and HRT was 10 min,respectively,the beginning and complete penetration time of microplastics in the modified rainwater bioretention system was significantly delayed than that in the traditional rainwater bioretention system.In the modified rainwater bioretention system,after HRT increased from 10 min to 30 min,polyethylene began to penetrate from 90 min(9 FVs)to 360 min(12 FVs),and polystyrene latex microspheres began to penetrate from 40 min(4 FVs)to 240 min(8 FVs).At high ionic strength(50.0 mmol/L),the system has a stronger ability to trap microplastics;pH and cation type have no significant influence on the retention effect of microplastics.