The Evaluation of Costs and Greenhouse Gas Reduction Using Technologies for Energy from Sewage Sludge

Sewage sludge is a biomass resource that can create a solid fuel and electricity. Utilizing sewage sludge as a renewable energy can contribute to the reduction of greenhouse gases. In Japan, the "National Plan for the Promotion of Biomass Utilization" and the “Priority Plan for Social Infrastructure Development" were approved at cabinet meetings in December 2010 and August 2012, respectively, to promote the energy utilization of sewage sludge. This study investigated costs and greenhouse gas emission in different sewage sludge treatments with technologies for energy from sewage sludge. Expenses were estimated based on capital costs and O&M costs including energy consumption of solid fuel plants and biogas power generation plants for sewage sludge. Results showed that the cost of sludge digestion treatment with solid fuel technologies was 8% lower than landfill disposal. The greenhouse gas emission of sludge digestion treatment with solid fuel technologies was also 6,390t as CO2 smaller than landfill disposal. Biogas power generation reduced the electricity of a wastewater treatment plant by 30% and the cost by 5%.

Authors:

• Futoshi Kakuta
• Takashi Ishida

Keywords:

• Global warming counter measure
• energy technology
• solid fuel production
• biogas.

References:

[1] Basic Plan on Promotion of Biomass Utilization (2010): Ministry of
Agriculture, Forestry, and Fisheries, pp11.
[2] Third Priority Plan for Social Infrastructure Development (2012):
Ministry of Land, Infrastructure, Transport, and Tourism, p79.
[3] Sewerage Works in Japan (2014): Japan Sewage Works Association,
pp84.
[4] Guidelines for Sewage Sludge Energy Generation Technology Revised
(2015): Ministry of Land, Infrastructure, Transport and Tourism, Water
and Disaster Management Bureau, Sewerage and Wastewater
Department, pp29-29.
[5] Master Plan Manual for Usage of Biosolids (Comprehensive Plans for
Sewage Sludge Treatment) (2004): Ministry of Land, Infrastructure,
Transport and Tourism, City and Regional Development Bureau and
Sewage Works Association, pp77-87.