Life cycle assessment of sewage sludge co-incineration in a coal-based power station

• LCA of sludge co-incineration in coal-fired power plants was studied.
• Sewage sludge co-incineration presents higher economic benefits.
• The efficiency of net coal consumption is a key to reduce environmental impact.
• Increasing incinerated ash reuse capacity can reduce environmental burden.
• Decreasing water content rate of sludge can increase overall environmental burden.

A life cycle assessment was conducted to evaluate the environmental and economic effects of sewage sludge co-incineration in a coal-fired power plant. The general approach employed by a coal-fired power plant was also assessed as control. Sewage sludge co-incineration technology causes greater environmental burden than does coal-based energy production technology because of the additional electricity consumption and wastewater treatment required for the pretreatment of sewage sludge, direct emissions from sludge incineration, and incinerated ash disposal processes. However, sewage sludge co-incineration presents higher economic benefits because of electricity subsidies and the income generating potential of sludge. Environmental assessment results indicate that sewage sludge co-incineration is unsuitable for mitigating the increasing pressure brought on by sewage sludge pollution. Reducing the overall environmental effect of sludge co-incineration power stations necessitates increasing net coal consumption efficiency, incinerated ash reuse rate, dedust system efficiency, and sludge water content rate.