SWAG agenda 082514 - Laserfiche WebLink

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Comprehensive Review of S olid W aste Collection and Disposal Options v2.1 170 10/22/12 Exhibit 12 -9. Basic Anaerobic Process 12.4.2.2 Aerobic Process The aerobic process relies on a continuous supply of air to be mixed in with the waste material. Again, the waste is ground up into pieces. Recyclable materials are removed before this process. In a typical plant the waste is ground up and formed on an outdoor pad into long piles called windrows. The windrows are agitated a few times per week to allow all parts of the pile to be exposed to air. The agitation and aerating process can also be conducted in a vessel into which air is forced. The aerobic environment supports a different, but also common microorganism that, like the anaerobic process, feeds on the organic fraction of the waste. The waste is converted to by-products that include CO2, water vapor and compost. Typically a site had to be located in a rural area; otherwise, the odors from the process could become a nuisance. 12.4.3 Bio-Chemical The bio-chemical process is based on breaking down the cellulosic part of the organic fraction of the waste stream. This would include certain foods (e.g., vegetables, fruits), paper products and yard vegetation. Biosolids can also be added as a waste material. All other materials in the waste stream should be removed prior to the process. In the process, following drying and shredding of the waste, the prepared waste stream is mixed with water and sulfuric acid in a closed reactor vessel. This causes a reaction that in conjunction with common bacteria already in the waste, breaks down the material into sugar compounds and a by-product known as lignin. There are some companies that are testing natural enzymes, instead of the strong acid chemical, to initiate this reaction.