Current Status and Trends of Municipal Sludge Treatment and Disposal in China

<p style="text-align:justify"><span style="font-size:10.5pt"><span style="line-height:200%"><span style="font-family:&quot;Times New Roman&quot;,serif"><a name="_Hlk170823277"><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">&nbsp; &nbsp; &nbsp; As urbanization accelerates, an increasingly significant problem of municipal sludge treatment and disposal has emerged in China. Sludge is both a waste and a resource, therefore, its reasonable and effective treatment and disposal are crucial for protecting the environment and promoting the recycling of resources. </span></span></a><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">This article reviewed the current status and technologies of sludge treatment and disposal, proposed the mainstream routes for sludge treatment and disposal in China, including anaerobic digestion-land application, drying incineration-construction material utilization, aerobic </span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">composting-land application, deep dewatering-emergency landfill. According to the comparative analysis of carbon emission, economic benefit and life cycle assessment, anaerobic digestion-land application </span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">was</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%"> considered the optimal technological route. It ha</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">s</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%"> extremely low carbon emissions</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%"> (</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">-44.43 kg·t^-1</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">) (calculated as CO₂/dry sludge)</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">, low net costs</span></span> <span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">($31.93/t)</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%"> and significant environmental benefits</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">, including </span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">SO₂(-1.9×10⁵kg), electricity (-6.2×10⁸kWh) and fuel (-4.6×10⁷MJ)</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">.</span></span> <span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">Based on this, it highlighted the issues in sludge treatment and disposal, such as vague policies, an incomplete management system, and inefficiency in the resource utilization of sludge. In response to these issues, suggestions were made to improve relevant policies, achieve more precise regulation, and establish an industrial chain for the resource utilization of sludge.</span></span> </span></span></span></p> <p style="text-indent:24.0pt; text-align:justify"><span style="font-size:10.5pt"><span style="line-height:200%"><span style="font-family:&quot;Times New Roman&quot;,serif"><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">In summary, this article offer</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%">ed</span></span><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:200%"> innovative insights into the optimal technological route for sludge treatment and disposal in China, while highlighting the practical engineering significance of addressing policy, management, and resource utilization challenges. Its recommendations have the potential to drive significant improvements in sludge management practices, contributing to a cleaner, greener, and more sustainable urban environment.</span></span></span></span></span></p>