Bioreactor landfill

The Solid Waste Association of North America (SWANA) has defined a bioreactor landfill as any permitted Subtitle D landfill or landfill cell where liquid or air is injected in a controlled fashion into the waste mass in order to accelerate or enhance biostabilization of the waste. ... 

Hybrid (aerobic-anaerobic). The hybrid bioreactor landfill accelerates waste degradation by employing a sequential aerobic-anaerobic treatment to rapidly degrade organics in the upper sections of the landfill and collect gas from lower sections. Operation as a hybrid results in an earlier onset of methanogenesis compared to aerobic landfills. 

The bioreactor landfill is a remedial alternative that can be applied either on site or off site. However, landfilling is regarded as the least attractive alternative at a site cleanup action. Landfilling of hazardous materials is becoming increasingly difficult and more expensive due to steadily growing regulatory control.92-93... 

Bioreactor landfill operations should comply with RCRA landfill facility standards under 40 CFR Part 264. It should be noted that SARA strongly recommends on-site treatment that permanently and significantly reduces the volume, toxicity, or mobility of hazardous substances, and utilizes cost-effective permanent solutions. The legislation prohibits land disposal of hazardous wastes unless U.S. EPA determines otherwise. U.S. EPA guidance for CERCLA responses requires most on-site disposal actions to attain or exceed applicable and relevant standards of all Federal public health and environmental laws unless specific circumstances dictate otherwise. 

The ET landfill cover is a complete cover, not a cover component. It offers opportunities for improved performance and lower construction and maintenance cost. In addition, the new cover may be beneficial for use with bioreactor landfills because ET covers can be designed to pass a controlled amount of precipitation through the cover and into the waste.4... 

It is evident therefore, that landfill gas production may be increased significantly by the addition of water, but that the volume of leachate will necessarily increase. The addition of water is a key requirement of the bioreactor landfill, and arguments relating to the advisability and technology of this landfill principle are discussed in Chapter 7. If the rates of waste degradation within landfill are to be increased, then optimisation of moisture content and flow is essential. For this to be achieved, effective control and treatment of leadiate will be necessary. However, the addition of excess moisture may not be necessary The moisture content of municipal solid waste is typically 20-30% in develop ... 

The information supplied above shows that waste composition, moisture content, waste particle size, waste density, temperature and pH will all affect both the extent and the rate of waste degradation.. However, very little of this knowledge has been utilised by landfill operators in their management of landfill sites until control of these parameters is attempted on an operational landfill, it will be impossible to know to what extent the bioreactor landfill can meet the... 

If containment of waste is one area where risk reduction can be realistically achieved, a second area with greater potential is that of hazard reduction. This can be achieved through careful control of waste inputs and through appropriate choice of landfill design and operation (e.g. bioreactor landfill, pre-treatment). The choice of design and operation of a sustainable landfill will be affected by the nature of the emplaced waste. If truly inert waste is deposited there will not be a hazard and sustainability will be easily achieved. Waste minimisation and recycling wUl impact upon the composition and hazardous nature of waste and the effects of these practices will affect the choice of sustainable landfill design. 

Dumps and landfills Sanitary landfills Controlled dumps Bioreactor landfills... 

A temperature of 40 °C, quite unusual for geotechnical applications, was chosen within the BAM certification because geomembranes in landfill liners may be exposed to elevated temperatures when the waste body of the landfill contains biodegradable materials and especially when it is run as a bioreactor landfill. 

Bioreactor landfills were designed to accelerate the degradation of municipal solid waste (MSW) in... 

Shao L et al (2006) Electrolytic degradation of biorefractory organics and ammonia in leachate from bioreactor landfill. Water Sci Technol... 

In general, landfills in the United States and Europe utilize a cap and seal strategy, wherein the bed of the landfill is lined with clay and then the top sealed to prevent contamination with ground water and to capture gases in the landfill. Landfill gases can be burned or collected to reduce dangers associated with overpressure. Methane can be captured in a bioreactor landfill for energy utilization. 

ASTM D7475-11, Standard Test Method for Determining the Aerobic Degradation and Anaerobic Biodegradation of Plastic Materials under Accelerated Bioreactor Landfill Conditions, American Society for Testing and Materials, PA, USA, 2011. 

For economic and regulatory reasons a bioreactor is built as a deep cell which should be completed within 2 5 years (Gupta et al. 2007). But, too deep a cell could cause a problem due to the slow infiltration of liquids through the heavily compressed waste layer in the lower part of the bioreactor landfill. 

Designing a system for leachate recirculation and distribution of liquids inside the bioreactor landfill. 

Shortening the waste stabilization time. The decomposition of waste in an anaerobic bioreactor landfill lasts years versus decades in dry tombs . Ensuring an adequate amount of water accelerates the decomposition of organic matter. According to Pacey et al. (1996) almost all of the rapid and moderately biodegradable organic constituents are decomposed... 

Decrease of pollutant concentrations in the leachate. Positive effects in the reduction of leachate strength in a full-scale bioreactor landfill were observed at Sea Carr Landfill. The COD in the leachate from the area with recirculation was always lower than in the control area (without recirculation). The differences became more apparent with time. After three years of observation the COD values in the recirculated leachate were approximately 15 g dm while in the control they exceeded 50 g dm . A similar trend was observed in the case of chlorine, and ammoniacal-N. During three years of observations concentrations of these substances decreased in both cells, but the lower values and a more pronounced drop were noticed in the cell where leachate recirculation was applied. After three years, the chlorine and ammoniacal-N concentrations in the recirculated leachate was about 1,600 and 500 mg dm" respectively, while in the leachate from the control cell they were about 2,100 and 800 mg dm, respectively (Bioreactor Landfill for Sustainable..., 2004). Recirculation of leachate from an active or closed landfill cell can be considered as an in situ leachate treatment method. It minimizes the hazard to the environment and reduces the leachate treatment costs (Reinhart et al. 2002). Due to the continuous recirculation of leachate the operator does not bear the costs associated with its pre-treatment and transport to the treatment plant. 

CRITICAL APPROACH TO ANAEROBIC BIOREACTORS LANDFILL TECHNOLOGY... 

Increased risk of fires or explosion. Rapid degradation of organic matter is a reason for the fast production of LFG. Gas venting systems used in conventional landfills may not be able to efficiently vent the bioreactor landfills which could cause an explosion (US EPA, 2006). 

Intensified odour nuisance. Compared to traditional landfills, bioreactor landfills produce more gases, such as HjS, which have an extremely putrid smell. 

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