Biosolids reduce NOx emissions from cement plants; new technique proven by Cement Industry Environmental Consortium.

VICTORVILLE, Calif.--(BUSINESS WIRE)--Dec. 15, 1995--The Cement Industry Environmental Consortium (CIEC) has announced the results of a major innovation which is yielding significant environmental benefits for Southern California.

The innovative technique, "biosolids injection," now being used at the state's largest cement plant, has resulted in a 45 percent reduction of smog-causing oxides of nitrogen (NOx) emissions while disposing of 10 percent of Southern California's wastewater sludge.

The use of biosolids for emission control is a major breakthrough. Principals involved with the CIEC, the public-private research organization responsible for the technique, explain that biosolid injection works because ammonia converts nitrogen oxide emissions, formed during combustion, into a stable and harmless form.

Wastewater sludge is naturally high in ammonia so when biosolids are mixed with combustion gases emerging from a cement kiln, NOx levels are dramatically reduced before being vented to the atmosphere.

NOx reduction is a priority of air-quality regulators because it accelerates smog formation. NOx is ubiquitous. It is a by-product of all combustion and everything from backyard grills to automobiles and industry produces it. Use of biosolid injection (BSI), however, will be limited to the cement industry.

The objective of the CIEC, a non-profit public-private partnership, is to develop pollution-control technology to enable operating cement plants to meet the newer, stricter standards required by the Clean Air Act.

The CIEC is comprised of three cement manufacturers -- Riverside Cement Co., Southdown Inc., and Mitsubishi Cement Corp. -- along with the California Trade and Commerce Agency and Mojave Desert Air Quality Management District.

Charles Fryxell, air pollution control officer of the Mojave Desert Air Quality Management District and a founding CIEC boardmember, commented that "BSI is what we were looking for when we set up the Cement Consortium."

Cement manufacture is highly energy intensive. The heart of a cement plant is a rotating kiln which pyroprocesses rock and minerals to 2,700 degrees F -- hot enough to ignite the feed which burns like so much lava. A cement plant's NOx emissions are sizeable, similar to that of a utility power plant.

Mitsubishi Cement Corp.'s Cushenbury plant outside Lucerne Valley is the state's largest cement plant. It hosted the early tests of BSI and has used the technique commercially since receiving formal approvals from the Mojave Desert air district earlier this year.

"While we meet current standards, the technology we needed to be able to comply with the new Clean Air Act didn't exist," explained Bud Biggs, Mitsubishi Cement's plant manager. "We knew that if we couldn't find a solution, we would have to invent it."

Biggs credits the program's success -- which is reducing Cushenbury's NOx emissions at a rate of 700 tons a year (a 45 percent decline) -- to a "team effort." Radian Corp. proposed the original concept for BSI in the spring of 1992.

Radian, with headquarters in Austin, Texas, is one of the nation's leading environmental engineering firms. The CIEC adopted the concept and sponsored the research leading to its commercialization. Biggs and his staff at Mitsubishi refined the technique.

Apart from improving air quality, the commercialization of biosolids injection is benefiting Southern California in another important way.

Disposal of wastewater sludge has long been troublesome. While land spreading and composting biosolids are both accepted practices, the waste material is costly to transport, and its odorous quality makes it undesirable anywhere outside a rural setting. Sanitary officials throughout Southern California are constantly challenged to find acceptable outlets for the 1.8 million tons of wastewater sludge annually generated in the region.

The Cushenbury plant currently consumes approximately 500 tons of biosolids daily. On an annual basis (and accounting for scheduled maintenance shutdowns at the plant), the Mitsubishi cement plant can dispose of about 155,000 tons of sludge. This is equivalent to 10 percent of the annual wastewater sludge generated by Southland sewage treatment plants.

"We have set up a win-win-win here," observes Eugene Moscaret of the California Trade and Commerce Agency and CIEC boardmember. "The cement plants reduce their emissions. The state keeps cement manufacturing jobs in California. And the region's sludge is put to beneficial use."

The CIEC has patented the BSI technique and plans to market it to cement plants around the world.

CONTACT: Robert Kahn, 916/444-9585

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