人工湿地基质再生技术的研究进展

人工湿地中基质对污染物的吸附是一个有限的过程,对其进行再生可减缓净化效果的下降趋势,降低周期性更换基质的材料消耗和购置成本,回用营养物质于农业。基质可以通过物理、化学或生物的方法原位或异位再生。其中生物再生成本低廉,生态友好且具有可持续性,是基质脱氮再生的最有效途径,可以通过优化离子浓度和交换速率,碳源、溶解氧、微生物群落结构等提高再生效果和速率。基质除磷物理再生效果受基质类型、磷浓度负荷、落干休作开始时机和持续时间等的影响,其操作简便,可在人工湿地的日常运行管理中原位实施。化学再生效果受基质种类、再生试剂的成分和浓度、环境条件如温度、pH值、Eh值和DO值等的影响,可在基质吸附饱和后作为应急措施使用。

Regeneration technology of substrates in constructed wetlands: A review

The adsorption of contaminants by substrates in constructed wetlands is a limited process. Regeneration of substrates can ease the downtrend of purification efficiency, reduce the materials consumption and acquisition cost of replacing substrates periodically, and reuse nutrient substance back to agriculture. Substrates can be regenerated through physical, chemical and biological techniques in situ or ex-situ. Biological regeneration, which is low-cost, eco-friendly and sustainable, is the most effective way to regenerate the substrates for removing nitrogen. The effect and rate of biological regeneration can be improved by optimizing ion concentration and exchange rate, carbon source, dissolved oxygen(DO), microbial community structure, and so forth. Physical techniques to regenerate substrates for removing phosphorus is affected by substrate types, concentration load of phosphorus, timing and duration of resting period, and so on. Physical regeneration, which is easy to operate, can be implemented in situ during the daily operation management of constructed wetlands. Chemical techniques to regenerate substrates is influenced by substrate types, composition and concentration of regeneration reagents, environmental conditions such as temperature, pH value, Eh value and DO value, etc. Chemical regeneration can be used as emergent countermeasures when substrates reach their adsorption saturation point.