Scheme of sewage sludge recycling

• Main Authors: Jie-xi Cheng, 程介羲
• Other Authors: Zhi-dong Lin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/56988574311121920193

碩士 === 國立中央大學 === 土木工程學系在職專班 === 103 === Abstract Sewage systems are an indispensable public facility of modern urban areas, and are an indicator of national competitiveness. As part of its active efforts in developing nationwide sewerage systems, the Executive Yuan ratified the “Phase 5 Sewage System Construction Plan” of the Construction and Planning Agency, which aims to increase the ratio of household pipelines connected to public sewage to 35.10% and the overall ratio of sewage treatment to 60.80% between 2015 and 2020; sewage sludge volume is expected to show sequential growth each year. Sewage sludge is rich with organic matter, inorganic matter, and heavy metals. This study collects data on domestic and foreign laws and regulations related to sewage sludge reuse, reuse technologies, characteristics of sewage sludge in Taiwan, corresponding laws and regulations, government policy, and the national situation. Sewage sludge reuse technology is divided into three categories, namely “renewable energy,” “green farmland” and “construction material,” and the strengths and weaknesses of each technology is analyzed from the perspective of technology, market, environment, and laws and regulations, evaluating the most technology for sludge reduction and discussing its feasibility. Considering that there are many methods for reusing sewage sludge, but sewage sludge reuse products cannot be used in farmland due to current laws and regulations, as well as objections from the Council of Agriculture (COA), this study proposes the use of sewage sludge carbonization equipment together with a cement kiln, so as to produce a product that conforms to current laws and regulations and satisfies the COA’s requirements. This study mainly uses waste heat from a cement kiln to carbonize sewage sludge. The organic waste gas generated from drying and carbonizing the sewage sludge is channeled back into the cement kiln for combustion, and then the carbonized product (auxiliary fuel) is mixed with coal and used as fuel for the cement making process. The ultimate objective is to mix sewage sludge ash into coal ash and directly uses it as part of the pozzolanic material application system.