基于元分析揭示全球尺度下反硝化反应器中基质材料对硝态氮去除的显著影响

Global Significance of Substrates for Nitrate Removal in Denitrifying Bioreactors Revealed by Meta-Analysis

反硝化生物反应器(DNBR)被广泛用于减少农业废水中过量的硝酸盐。其性能取决于基质的物理和化学性质。在以前的研究中,已经对一部分常见基质做了总结。然而,很少有研究尝试确定基质类型在硝酸盐去除中起作用的一般模式。本研究利用从63篇同行评审文章中收集的数据总结了41种基质类型,包括219个独立DNBR单元。基质分为四类:(1)天然碳(NC),如木屑;(2)非天然碳(NNC),如可生物降解聚合物[如聚己内酯(PCL)和废品(如纸板)];(3)无机材料(IM),如非碳材料(如氧化铁);(4)复合材料(MM),如上述材料的混合物。通过对硝酸盐去除速率[NRR,氮去除(g·m^(-3)·d^(-1))]和硝酸盐去除效率(NRE,%)的元分析,对这些材料进行比较和评估。本文综合阐述了基质效果(NRR和NRE)、潜在机理、污染交换和成本分析。我们的分析表明,木屑和玉米芯是NC中最具成本效益的基质。对比所有参与研究的基质,我们建议将MM作为最优基质,尤其是具有很大的改进空间的基于木屑和玉米芯的基质。该分析有助于优化DNBR的设计,以满足使用者对环境、经济和实用的需求。

Denitrifying bioreactors(DNBRs)are widely used to reduce excess nitrate from agricultural drainage.Their performance depends on the physical and chemical properties of the substrate.Common substrate types have been partly reviewed in previous studies.However,few studies have attempted to determine a generalized pattern for the role of substrate type in nitrate removal.This study summarizes 41 types of substrates using a dataset collected from 63 peer-reviewed articles,which include 219 independent DNBR units.The substrates are classified into four groups:①natural carbon(NC),such as woodchips;②non-natural carbon(NNC),such as biodegradable polymers(e.g.,polycaprolactone(PCL)),and waste products(e.g.,cardboard);③inorganic materials(IMs),such as non-carbon materials(e.g.,iron oxide);and④multiple materials(MMs),such as a mixture of the above materials.These materials are compared and evaluated through a meta-analysis of nitrate removal rate(NRR;N removal(g·m^(-3)·d^(-1)))and nitrate removal efficiency(NRE).This study reviews substrate performance(NRR and NRE),potential mechanisms,pollution swapping,and cost analysis.Our analysis indicates that woodchips and corncobs are the most cost-effective substrates among NCs.In a comparison of all the studied substrates,MM substrates are recommended as the optimal substrates,especially woodchip-based and corncob-based substrates,which have great potential for improvement.This analysis can assist in optimizing the design of DNBRs to meet the environmental,economic,and practical requirements of users.