The potential for recycling municipal sewage sludge as a substrate for wetland creation

Municipal sewage sludge (MSS) is proposed as a suitable substrate for wetland creation. Sludge disposal is currently limited to terrestrial conditions due to concern for the transmission of pollutants. Wetland structure and wetland biogeochemical cycles were compared with sludge disposal practices to identify strengths and weaknesses in wetland mechanisms for pollution control. Potential pollution from sludge use is proposed to be mitigated both by wetland function and by the substrate construction method. Because MSS requires specific handling techniques to prevent undesired release into the environment, to protect workers and to be practical for construction, designs responsive to the nature of the construction material were necessary. Three designs were developed, evaluated and compared in terms of aesthetics, educational opportunities, environmental safety, nutrient cycling, waste material utilization, substrate construction requirements and wetland establishment requirements.