"Just add water" to get rid of trash faster.

• Position: Waste Management - Brief Article

Trash in a municipal landfill could decompose nearly 10 to 20 times faster than it normally does through a system that keeps the trash continually wet. Landfills are normally dry environments, and the lack of adequate moisture doesn't allow biodegradable trash to decompose as quickly as it should, according to researchers at Ohio State University, Columbus.

In fact, keeping a landfill saturated means it could stabilize in five to 10 years, instead of taking the average 100 years or longer to do so, indicates Ann Christy, assistant professor of food, agricultural, and biological engineering. In a stabilized landfill, the majority of trash already has decomposed. "Quicker decomposition rates mean more room for more trash in the same landfill, which would cut down on the need for additional landfill space. This also feeds into recycling--once the biodegradable material decomposes, we can extract recyclables from the landfills, then the landfills aren't filling up as quickly."

Christy is currently experimenting with moisture levels in two laboratory-scale wet-tomb bioreactors. A wet-tomb bioreactor is a self-contained unit with water purposely pumped in. The water creates an environment suitable for bacteria actively to decompose waste. The water is recirculated throughout the system.

Christy and her colleagues monitored the experimental bioreactors for 15 months. Each bioreactor--or bin--was filled with approximately 3,300 pounds of nonshredded municipal solid waste collected from a local sanitary landfill. (While many small-scale landfills require waste to be shredded in order for it to fit, shredding is not economically feasible for a full-scale landfill, Christy maintains.) The bins were three feet long, six feet wide, and three feet tall. The researchers could watch the decomposition through a two by two-and-a-half-foot Plexiglas observation window installed in each bin.

The waste in one bin was covered with a single layer of sludge--sewage already decomposed by bacteria. Sludge has been used in landfills...