The state of California has done great job of reaching its 50-percent waste diversion goal. We are now entering a phase of that will require us to achieve even higher recycling rates to reach increasingly stringent state goals.
This means several things -- new recycling technologies will need to be developed and implemented, and more green jobs will likely be a result. Another outcome is the potential for using what was once our waste as resources.
According to the state, one of the largest portions of landfilled materials is organics such as food, yard clippings, leaves, and wood. Since organics make up about 25 percent of our "garbage," there is a major push in California to divert organics from landfills. The main reason is because environmentally harmful gases -- methane in particular -- are created when these types of materials are buried. Another motive for diverting organics from landfills is that they actually can be converted into resources.
Methane is generated in landfills as waste decomposes under anaerobic (without oxygen) conditions. Methane is considered a potent "greenhouse gas" by the US Environmental Protection Agency and is about 23 times more harmful than carbon dioxide.
Reducing this methane can be accomplished, in large part, by developing and implementing organics recycling programs. For example -- many municipalities, including some in Central Contra Costa -- allow residential food scraps to be
Food scrap recycling programs are very popular, but they also come with their own set of challenges. Typical household organics (e.g. food scraps and yard trimmings) are collected and taken for processing to large composting facilities, which are usually outdoors. This poses issues with smells, pests and dust in the areas where the compost site is located. The result is that many communities oppose having large-scale commercial composting in their community. Therefore, compostables are usually transported to more rural areas that will allow such facilities.
One way to circumvent the issues associated with industrial composting is to develop new types of facilities and techniques to process recyclable organics. These innovative systems vary, but the trend is toward smaller enclosed composting sites that can be located in more populated areas. This strategy decreases the cost of transportation and methane emissions.
A local example is the Central Contra Costa Solid Waste Authority's Commercial Food Waste Recycling Project partnership with East Bay MUD and Allied Waste Services. Local commercial food waste is collected and deposited in large holding tanks called digesters. Like at a landfill, this anaerobic process creates methane. But East Bay MUD captures the gas and uses it to create electric power at its Oakland facility. The solid residuals from this process, like compost, are used as a soil amendment.
Industrial compost operators can also cover or enclose their compost piles and capture and filter the emissions. In 2008, the Inland Empire Regional Composting Facility in Southern California began doing just that. Their facility is an extensive indoor operation, using a large abandoned commercial warehouse retrofitted with a massive air filtration system.
A method called dry fermentation also uses an enclosed system and creates useful soil amendment and biogas energy. However, this technique does not require grinding of the waste or introduction of water into the system, like other composting processes do. Through dry fermentation,about 60 percent of waste that goes into the system is left over as compost after the relatively short 28-day cycle. The City of San Jose is currently developing a dry fermentation digester facility adjacent to the Zanker Road Landfill, which should be operational in approximately two years.
Although diverting organics will reduce the amount of methane from the landfills, there are ways to further decrease these gas emissions. Many California landfills, including our local Keller Canyon landfill near Pittsburg, owned by Republic Services, capture methane at the site and converts it into electrical power.
The development of new waste management technologies holds much promise in helping to reduce associated impacts on the environment, while producing important resources. Compost helps farmers and gardeners grow better plants, and methane can be turned into electrical power. Like the old saying goes, "let's make lemons into lemonade" ... let's make waste into resources.
If you have a question, comment or idea about current or future solid waste programs, please email them to email@example.com