Teaching ecosystem ecology through studying sewage treatment

Sewage treatment plants offer an excellent model ecosystem in which inputs and outputs can be quantified, and the response of the system to change measured The dynamics of ecosystem functioning can be difficult for students to appreciate when systems are complex and difficult to quantify, in terms of flow of energy and cycling of matter. Most ‘textbook’ examples of real ecosystems are based on data collected over many years of study. A sewage treatment plant offers a working ‘model’ of an ecosystem but one which is still relatively complex, yet quantifiable. If is also a system which mimics a number of the transformations of energy and matter, which go in real ecosystems. It allows students to clearly understand the relationships between inputs and outputs, whilst being introduced to the design principles of environmental engineering required to design such an artificial ecosystem.