Water reclamation and sludge recycling scenarios for sustainable resource management in a wastewater treatment plant in Kinmen islands, Taiwan

Abstract

Sustainable resource management in small islands is very challenging. To address the challenges, four water and waste management strategies were proposed for a wastewater treatment plant in the Kinmen islands, Taiwan. Life cycle assessment was employed for evaluation of the environmental impacts and benefits (i.e., avoidance of impacts) associated with the resource management strategies at the plant. The results showed that the energy requirements (mainly electricity consumption) for water and sludge treatments in the wastewater treatment plant had the most remarkable impact as high as 98.6%. Significant environmental advantages could be achieved by reusing the reclaimed wastewater for agricultural applications (27.8% reduction in eutrophication potential), reusing the sludge for land applications (157% reduction in global warming potential), and generating energy from incineration of recycled sludge (impacts were neutralized). Impacts from addition of tertiary treatment for wastewater reclamation could be offset by preventing discharge of nutrients (i.e. N and P) into the environment. The reclamation also reduced the demand from groundwater pumping and associated impacts. Reuse of sludge for energy generation was more favorable than for land applications. This was mainly because eutrophication impact could not be avoided when the sludge was applied to soil (excess in nutrients), and, relatively higher reduction in global warming potential was observed for energy generation (−197 kg CO2 eq/m3) than for land applications (−18.8 kg CO2 eq/m3).