After completing a comprehensive study on the impacts and benefits of food waste disposals, in September, 2008, the Stockholm Water Board voted to allow the installation of disposals in all areas of their jurisdiction without prior approval, and also eliminated previously required surcharges. This action was endorsed by the Swedish Green Party in April, 2008, which argued that the aggressive use of food waste disposers is consistent with the national strategy to divert 35% of household food waste from incineration to biological recycling by 2010. Stockholm currently sells biogas to produce energy, and has excess digester capacity at its wastewater treatment plants to increase the amount of biogas the plants capture. Read more here: [Original Article] [English version]

The U.K. counties of Worcestershire and Herefordshire near Wales began subsidizing the purchase of disposals by residents in 2005, after studying the issue and concluding that using disposals was a cost-effective, convenient and hygienic means of diverting kitchen food waste from landfills. According to their analysis, using in-sink disposals for food waste costs less and has a better carbon footprint than other waste disposal options. The counties estimated that lower solid waste disposal costs would pay for the cost of subsidies in about three years. Read more here: http://www.insinkerator.com/pdf/fwd_eis_summary.pdf

In 2000 the city of Sydney, Australia investigated the impact of food waste disposals in five areas: technical/operational for sewer systems; environmental; economic, microbial risk and social acceptance. It focused on apartment buildings because at the time they had the highest per capita installation of disposals, but results were considered representative. The impacts of disposals in each area was compared to the impacts of the current practice of collecting food waste with municipal waste and sending it to landfills, centralized composting of food and garden waste, and home composting. Among the report‘s conclusions was that the disposal of food with municipal waste was the least satisfactory of all options; individual composting was environmentally ideal but impractical for multi-unit dwellings. Using a food waste disposal was second best for energy consumption, global warming potential and acidification. Read more here: http://www.insinkerator.com/pdf/Wainberg et al, CRC Sydney, Australia (2000).pdf

New York City had banned food waste disposals in areas served by combined storm and sanitary sewers since the 1970s. In 1995 the City Council directed the city‘s Department of Environmental Protection to conduct a 21-month pilot project that studied the impacts of using disposals on the environment, public health and the cost of operating the water and sewer system. Among the issues examined were the impact of grease and food solids on sewers, the impact on water consumption and the impact of possible increased pollutant loading on receiving waters. The study concluded that the impact of food waste disposals in any of these areas was “de minimus,” and the previous ban was overturned. Read more here: http://www.insinkerator.com/pdf/grinders.pdf

To fully assess the potential benefits and impacts of food waste disposers, Japan‘s Ministry of Land, Infrastructure and Transport, in cooperation with the Hokkaido government and Town of Utanobori, designated the town as the subject area for a disposal field test conducted over four years from 2000 through 2003. The study assessed the impacts of disposals on the sewage system, solid waste collection; and the daily lives of town residents, economy and environment. A technical report on the study found the installation of disposals did not result in any changes in the amount of system water usage; almost no deposits accumulated in even gently sloping sewer lines; no large changes were evident in the amount of foreign material and deposits discharged at pump facilities, and the frequency of cleaning did not change; no effects were observed to the quality of treated water, although waste sludge increased; the popularization of disposers would cause no changes to the environmental burden; and an overall cost benefit analysis found that the convenience benefits and the cost of purchasing and installing a disposer to be an excellent value when compared to the changes in administrative costs and disposal operation costs. Read more here: http://www.insinkerator.com/pdf/Utanobori, Japan (2005).pdf

Food waste disposals were relatively unknown in the Netherlands in 1996 when two researchers, Dr.ir. J. de Koning and Professor ir. J.H.J.M. van der Graaf from the Section of Sanitary Engineering at the Delft University of Technology studied the effect of their use on sewer systems and wastewater treatment. Their conclusions were that using food waste disposals had a negligible impact on both. Then eight years later, at the request of the Dutch government, Dr.ir. J. de Koning conducted a follow-up study specifically to quantify the impact of food waste loading to the Dutch sewage system and the effects of disposal use on the biological wastewater treatment process. The context was a government-mandated system that collected kitchen, food and garden waste for centralized composting. The study, concluded in July 2004, produced data that reinforced the conclusion that the organic loading emanating from food waste disposers present negligible impacts to the sewer system or wastewater treatment facility. In addition, the author concluded that the use of food waste disposals could be a useful addition that would improve the current system for the collection of kitchen, garden and food waste, specifically in areas where because of environmental and/or economical reasons the separate collections had been abandoned. Read more here: http://www.insinkerator.com/pdf/delpht.pdf

The National Association of Heating, Plumbing, and Cooling Contractors commissioned a life-cycle comparison of five engineered systems for managing food waste. The comparison looked at the required land, total system energy, total system materials, total emissions to the environment and total system costs for each method. The five systems were sending it through a food waste disposal to a wastewater treatment plant; collecting it with municipal solid waste and sending it to a landfill; collecting it with municipal solid waste and sending it to a community compost facility; collecting it and sending it to a central incineration facility; and sending it through a food waste disposal to a septic system. The four-year research project was concluded in January 1998. Read more here: http://www.insinkerator.com/pdf/uwstudy.pdf

This document reviews eighteen (18) of the most recent studies conducted by universities, research institutions, and government agencies across the United States and in many countries that examine the efficacy of food waste disposers. It compiles and organizes the findings regarding all facets of the sewage collection, treatment, and disposal process. Read more here: http://www.insinkerator.com/pdf/Summary_of_Research_2006.pdf

In today’s world, food waste disposers can now be considered an environmental appliance – much like EnergyStar-rated refrigerators and laundry machines. Acknowledging the “wisdom of crowds,” disposers are now approved for sale in over 80 countries – based on decades of research and widespread use that support the essential role disposers play in diverting food waste from collection trucks, landfills and incinerators. Read more here: http://www.insinkerator.com/pdf/The_Wisdom_of_Crowds_2006.pdf