Fuel in Sewage Sludge Incineration

Abstract

As a result of a demonstration project partly sponsored by the United States Environmental Protection Agency in cooperation with the Indianapolis Center for Advanced Research, the City of Indianapolis, Indiana, realized a 34% fuel savings for sewage sludge incineration. At the same time, sludge throughput was increased 10%. In addition to these proven savings, operational downtime for repairs was reduced, maintenance costs were reduced, and air pollution was reduced. The air pollution reduction allowed Indianapolis to cancel a $3,000,000 construction program for air pollution abatement.

Other cities incinerating sewage sludge in the United States that have initiated the fuel efficient mode of operation have saved even more fuel than Indianapolis. Nashville, Tennessee, reduced its fuel usage 40%; Buffalo, New York, reduced its fuel usage 47% from design expectations; Hartford, Connecticut, reduced its fuel usage 51%; and Jacksonville, Florida has reduced its fuel usage over 50%.

These savings result from installing additional instrumentation and controls (often not required at newer facilities), modifying the incinerator operating methods, and training the operators to operate the facilities more efficiently. At Indianapolis, it cost $20,000 per incinerator for instrumentation and operator training. This was ah older plant and required a maximum amount of new controls and instrumentation; however, the payback for this $20,000 was less than three months due to the reduction in fuel use based on an oil price of $0.264 per litre ($1.00 per gallon). In the other cities where instrumentation controls were adequate, the cost for developing the now operating mode and training the operators averaged $75,000 per city.