The pH in a landfill layer affects many phenomena such as dissolution/precipitation and adsorption/desorption of heavy metals, activities of microorganisms, CO2 absorption/emission etc. However, because of a lack of knowledge about the leachate characteristics after closing a landfill site, some inhabitants around a landfill site that has been constructed or is under consideration are anxious about the environmental safety of the landfill site, and often oppose the construction of a new landfill site. Therefore, it is very important to predict the pH change for a long term period for the management of a landfill site after closing. In order to predict the pH in a landfill layer, it is necessary to know the total amount of alkali and acid and their supply and consumption rates.
In order to evaluate the alkali elution rate from MSW incinerator bottom ash for a long term period, sequential leaching test of 6 sizes of sieved ashes was conducted with nitric acid as a solvent. The pH of the solvent was stepwise changed to 1.7, 2.7 and 4. After changing the pH of the solvent to 4, for a leaching time of more than 2 days the pH of the leachate remained constant, at about 7 for any particle size of bottom ash. The elusion rate of total alkalinity (
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Quelle: | Specialized Session D (Oktober 2007) | |
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CLONIC: CLOSING THE NITROGEN CYCLE FROM LANDFILL LEACHATES. A BIOLOGICAL PROCESS WITH PARTIAL NITRITATION AND ANAMMOX FOLLOWED BY THERMAL DRY TREATMENT.
© IWWG International Waste Working Group (10/2007)
CESPA, being part of the Ferrovial Group, is a leader in waste management and urban services in Spain. CESPA has a long experience in landfill construction and management, having a total of 37 landfills either in property or in exploitation. As one of the legal and environmental requirements, a suitable leachate treatment must be applied before the discharge to the receiving media. Thus, the decision to choose for an specific leachate treatment depends on different parameter such as: the landfill site location, physical location of the leachate treatment plant, the leachate quality, the discharge requirements and the best technologies available.
MODELING OF TRANSPORT AND GEOCHEMICAL PROCESSES BETWEEN LANDFILL LEACHATE AND A SATURATED BARRIER SYSTEM
© IWWG International Waste Working Group (10/2007)
Landfill leachate is a dangerous and polluting solution formed by a very complex sequence of physical, chemical and biological processes modifying the rainwater that percolates through waste (Bogner et al.,1996). Migration of the pollutants from the waste material into the percolating water is another important phenomenon requiring attention (Mora-Naranjo et al., 2004). The resulting leachate is a solution containing dissolved organic matter, inorganic macrocomponents, heavy metals and xenobiotic organic compounds and is characterized by reducing redox state (Christensen et al., 2001). Migration is a long-term and continuous process and the leachate may evolve and pollute the surrounding environment for hundred of years (Ustohalova et al., 2006).
A COMBINATION OF COGENERATION, EVAPORATION AND MEMBRANE TECHNIQUE FOR LANDFILL LEACHATE TREATMENT
© IWWG International Waste Working Group (10/2007)
Landfill leachate treatment is an actual point of interest for many landfills managers mainly due to the regulations that are changing in several countries and that impose more restrictions. Traditionally there are several types of techniques applied to landfill leachate treatment:
- Evaporation
- Membranes techniques;
- Biological treatment
- Chemical-physical treatment.
EMISSIONS MEASUREMENT AND GAS CAPTURE FROM A HORIZONTAL PLANE BASED GAS COLLECTION SYSTEM
© IWWG International Waste Working Group (10/2007)
In an effort to increase waste biodegradation rates, landfill operators in the United States have been actively recirculating leachate and pursuing bioreactor landfill practices that utilize additional liquids from outside sources to increase the moisture content of the waste. The preferred waste moisture content range of these advanced sanitary waste cells is 35% to 45% (wet weight basis). Historically, U.S. landfills have used vertical gas well systems for the recovery of landfill gas. With the onset of over 150 leachate recirculation projects in the U.S. and over 20 bioreactor landfills, an increase in maintenance costs in the vertical well fields and a potential for increased surface emissions have been noted. The classic vertical well systems have been filling with leachate. This has resulted in the need for the installation of automatic pump out systems and an increased frequency of maintenance to reduce surface emissions.
TREATMENT OF LEACHATE FROM A LARGE HAZARDOUS WASTE LANDFILL SITE IN SOUTH AFRICA
© IWWG International Waste Working Group (10/2007)
The Vissershok Waste Management Facility is a privately owned hazardous waste landfill site, located to the north of Cape Town in South Africa. The joint owners are South African waste management companies, Enviroserv Waste Management and The Wasteman Group (partly owned by Suez Environment). Forty hectares of the site is permitted to receive H:H (high hazard rating) waste and has been in operation since 1974. It has an anticipated life to between 2020 and 2025. The facility presently receives about 300 000t of waste per annum of which some 23 percent is hazardous. The site provides disposal and treatment facilities for many types of hazardous waste. In addition there is an encapsulation process for wastes that cannot be treated or disposed of onto the landfill.