Scenario analysis of source management practices: Impact on sewerage networks

Developments in urban areas increasingly consider the sustainability of water and wastewater management in their planning. One aspect of sustainability refers to the condition where water supply is sourced locally and wastewater discharges are utilized locally as alternative resources on a fit for purpose basis. Source management practices (SMPs) such as demand management, greywater reuse, rainwater use and sewer mining offer benefits of water saving and wastewater reduction. While the positive effects of SMPs have been widely acknowledged, the implementation of SMPs is also likely to alter the wastewater quality and flow characteristics. These alterations might affect downstream sewerage networks and wastewater treatment plants. SMPs tend to lower the wastewater flow, which subsequently increases the concentration of contaminants. Lower flow and higher contaminant concentration lead to increases in sewer problems such as blockages, odour and corrosion. Sewer blockages due to these SMP have been assessed in a few studies, whereas impacts of SMPs on odour and corrosion have not yet been investigated. The problems of odour and corrosion are frequently observed in sewerage networks, especially in areas with warm climate. These problems are caused by hydrogen sulphide (H2S) that is released into the sewer atmosphere. H2S formation in sewers is dependent on the wastewater quality and flow characteristics