Garbage disposers, are they greener option for waste management? Well, let’s see. Garbage flows from various directions and there is no way in which you can reduce it. In the US, more than 31 million tons of solid wastes in form of food scraps are generated each year. The kitchen wastes are often secured in trash cans that emptied in a local disposer. They are thereafter truck-loaded to landfills. Disposing food waste in the landfill has it consequences. The food waste would gradually decay in the open area emitting methane, a greenhouse gas almost 21 times more potent in trapping heat in the atmosphere than carbon dioxide. The waste would also produce an acidic liquid residue (leach ate) that can seep into ground water. You should also not forget the gas-spewing trucks that ply all over the city to transport the waste to the landfills.
Another eco-friendly way of disposing garbage is home composing. But given the fast pace of modern life not many of us will be able to avail time for it. Also the urban setting with its high-rises, frigid weather will not be suitable for composing.
The garbage disposers
A greener way of disposing food waste has been found in form of garbage disposers that are fitted under the sink. These units grind the food scraps into small pieces and pulp and push them down your pipes. The liquid food waste is drained to the sewage system.
According to InSinkErator, a leading manufacturer of in-sink garbage disposers, almost 70% of food scraps are water. About 30% of it is solid. This is screened out by the wastewater treatment plant and is sent to the landfills where it is decomposed in the absence of oxygen to produce methane. The can be a great source of energy. The wastewater plants also have a way to reuse leftover food screened from the waste water as fertilizer.
The other side
According to life cycle analysis expert Eric Massenet, PhD, of Northwestern University, and Debra Shore, commissioner of the Metropolitan Water Reclamation District of Greater Chicago, the in-sink disposers surely have some clear advantages over trash cans but they are not the greenest way of disposing uneaten food. Well let’s turn our attention now to the other side of the spectrum.
Running your semisolid food waste down the drainage system increases the likelihood of clogs. Food waste has a high content of grease and oil that solidify at room temperature and can build up inside pipes. It not only causes day-to –day inconvenience to the homeowners but also lead to sanitary sewer overflows. The San Francisco Public Utility Commission spends about $3.5 million per year to clear grease-related blockages.
Another point that should not be missed in this aspect is that conveying food waste through the sewer lines also requires lots of water. This goes against conservation of precious water and also encourages high energy use for pumping water and wastewater.
Dumping food waste into the waste water system also has other consequences. The waste water after treatment is evacuated into local water streams. They can change their chemical composition and harm aquatic lives. At an extreme level this impact is called as eutrophication. A higher concentration of nutrients results in algae blooms. According to an Australian research, the impact of eutrophication is three times larger than sending food waste to the landfills.
Also using the solid food waste from the wastewater as fertilizers may not be safe.