Biodegradation in Green Infrastructure

This chapter introduces biodegradation processes in general and sustainable drainage systems (SuDS) in particular. Biodegradation results in the biologically mediated breakdown of pollutants, to simpler materials, and if biodegradation is considered to be complete and irreversible, then the final product should include a gaseous component of a nutrient cycle. One of the most important aspects of both biodegradation and detention of pollutants in a green SuDS system is the formation of a biofilm. In the design of SuDS, where biodegradation is to be encouraged, conditions should be provided in which attached biofilm development is encouraged and where materials for degradation are concentrated where the biofilm is most easily maintained. Nitrogen can enter SuDS in a variety of forms, including both reduced, oxidised inorganic nitrogen, and both dissolved and particulate organic N. The relative importance of inorganic versus organic forms can vary as a function of land use.