Common use of Process Description – Maplewood Landfill Bioreactor Clause in Contracts

Process Description – Maplewood Landfill Bioreactor. The landfill bioreactor program that would be implemented at the Maplewood Landfill involves application of leachate from the landfill and small quantities of other liquids (e.g., truck, tire waste water, wastewater treatment plant sludges, or stormwater) to the waste. The liquids will be applied over an approximate ten acre area at or near the surface of the landfill as it will exist in September, 2000. The primary purposes of recirculating leachate in this manner is to treat the leachate and to increase the rate of biological degradation of waste in a portion of the landfill where liquids are applied. The potential benefits of the bioreactor are presented in Table 3. Treatment of leachate occurs within the waste when the microbes that naturally exist in the landfill consume portions of the leachate and waste material. Several studies (including some described in Table 2) have shown that leachate quality improves over time when leachate is recirculated on a regular basis. As an example, Table 4 and Figure 4 show leachate quality improving over a period of about seven years at test cells operated by the Delaware Solid Waste Authority’s Central Solid Waste Management Center (CSWMC). Recirculation of leachate can also result in accelerated generation of landfill gas; an example of accelerated landfill gas generation for the two test cells at CSWMC is presented on Figure 5. Further, at bioreactor landfills, substantial settlement of the waste typically can occur during the operating life of the landfill, thus stabilizing the waste mass and reducing the need for long-term maintenance during the post-closure care period. This settlement can significantly increase the usable waste disposal capacity compared to the facility’s original design capacity. Most importantly, bioreactor processes reduce the time needed to achieve a stable waste mass after closure. Finally, because the waste mass is more stable, it has more potential end-uses.