A Discussion of the Scientific Principles Underlying The Effective Phytotreatment of Stormwater = A Discussion of the Scientific Principles Underlying The Effective Phytotreatment of Stormwater

다국어 초록 (Multilingual Abstract)

Rapid urbanisation in Auckland, and other urban parts of New Zealand, has resulted in increased generation of stormwater containing dissolved pollutants such as heavy metals and synthetic organics, which can be difficult to remove in conventional filters. In addition, the accumulation of contaminants can lead to decreased filter performance. Bioretention systems may offer a solution. These systems generally consist of an engineered permeable soil with specific vegetation and associated microorganisms. During a storm event, runoff entering the bioretention system infiltrates the soil, where sediments and dissolved pollutants are retained. In the period between rain events, contaminants are mobilized by compounds produced by plants and bacteria. Subsequently, plants can take up the dissolved contaminants via their root network. Additionally, pollutants can be degraded by plants and the associated microbial communities in the rhizosphere. Plant matter can be regularly harvested for disposal. While the design and implementation of such systems appear to be simple, this simplicity is deceptive as suggested by the variable and often poor performance of such systems in practice. The processes occurring in the rhizosphere are varied and complex. This paper presents a review of the processes occurring in a stormwater bioretention system with the objective of motivating discussion on ways to improve the performance of such systems.