Page 132 - Wastewater Solids Incineration Systems

Combustion Technology 99

membrane filtration, anaerobic digestion, and air floatation, to meet required
effluent specifications. The CO byproduct stream and dryer exhaust streams are
2
directed to a recuperative thermal oxidizer to oxidize any volatile organic com-
pounds in the gases.
EnerTech has operated one plant in Japan, which only operated on slurried
organic solid waste and had a capacity of 20 metric tonne/d (22 ton/d) of dry solids.
A demonstration-scale facility has been operated in Atlanta, Georgia using residuals
from several WWTPs.
In southern California, EnerTech is developing a regional facility at a site adja-
cent to the Rialto wastewater treatment plant. The site is in a heavily industrialized
area. The facility will process approximately 178 metric tonne/d (196 dry ton/d)
from five municipalities and produce approximately 150 metric tonne/d (167 ton/d)
of product.
EnerTech states that the process is a net producer of power, generating an excess
of 1.25 to 1.5 times the energy requirement, although the understanding is that this is
based on the use of undigested sludge. Feed solids concentration is limited by the
ability to pump the feed cake before heat treatment. Several cement kilns within an
80-km (50-mile) radius of the proposed site in Rialto have expressed interest in the
fuel product. Tests conducted by General Electric show that NOx emissions from the
char is similar to coal and that SOx and other emissions are lower, providing a
cleaner burning fuel overall. The ash from burning the fuel is used in the cement
process and, therefore, does not require disposal.

11.0 REFERENCES

California Integrated Waste Management Board (2001) Conversion Technologies for
Municipal Residuals. Background Primer for the Conversion Technologies for
Municipal Residuals Forum; Sacramento, California, May 3–4; CIWMB: Sacra-
mento, California.
Dangtran, K.; Holst, T. (2001) Minimization of Major Air Pollutants from Sewage
Sludge Fluid Bed Incinerators. Proceedings of the 74th Annual Water Environment
Federation Technical Exposition and Conference [CD-ROM]; Atlanta, Georgia, Oct
13–17; Water Environment Federation: Alexandria, Virginia.

European Commission (2000) Directive 2000/76/EC of the European Parliament and
of the Council of 4 December, 2000 on the Incineration of Waste. Brussels, Belgium.