Leachate is produced when water moves downwards through a landfill, picking up dissolved materials from the decomposing wastes. The amount of leachate produced is directly related to the amount of precipitation around the landfill. Landfill leachate is defined as a liquid that seeps through solid waste in a landfill, producing extracted, dissolved, or suspended materials. It is a potential pollutant that may cause harmful effects on groundwater and surface water that surround a landfill site unless it is returned to the environment in a carefully controlled manner.
Leachate contains high amounts of organic compounds, ammonia, heavy metals, a complex variety of materials, and many other hazardous chemicals. The quantity of this leachate is generally small compared with that of other wastewater, but its contents are extremely hazardous in this regard, dedicated treatment facilities are required before leachate can be discharged into the environment.
Researchers worldwide are still searching for a total solution to the leachate problem. Various site-specific treatment techniques can be used to treat hazardous wastewater depending on leachate characteristics, operation and capital costs, and regulations. The treatment technology that can be used may differ based on the type of leachate produced. Even after treatment, the effluent characteristics are always hard to comply with the discharge standard leachate treatment schemes likely to include biological, physical, and chemical processes; their combination and specific modifications are greatly influenced by the characteristics of leachate produced.
Leachate in classical wastewater treatment plants is rarely treated because of its nature and high levels of pollutants (i.e., high chemical oxygen demand [COD] and ammonia content and low biodegradability). Treatment by a conventional water treatment system (i.e. a combination of sedimentation, biological treatment, filtration, and carbon adsorption) cannot remove salts or organics, such as harmful recalcitrant compounds. Therefore, the papers of this special issue will address research on advanced processes for landfill leachate treatment and the related areas. Ozone is one of the chemical processes used in the water industry, and recently ozonation has been given significant attention in the treatment of landfill leachate in order to increase oxidation potential and reduce the treatment time in pre or post-treatments that utilise a combination of ozone and other treatment techniques. Although ozone is effective in leachate treatment, the treatment efficiency for stabilised leachate still needs to be improved. This improvement can be achieved through the use of advanced oxidation materials and techniques.
Suitable topics include, but are not limited to, the following:
- Combination of ozone and other advanced oxidation processes (AOP) processes
- Sequential and simultaneous ozonation processes
- Combination of ozonation with physical and chemical treatments
- Biodegradability improvement of landfill leachate
- Influence of ozonation on leachate compositions
- Pre and post ozonation processes
- Chemical reactions and mass balance during ozonation
- Modelling and computation
- Other related topics of ozonation in landfill leachate treatment
Submission of manuscripts: 31 March, 2017
Notification to authors: 30 June, 2017
Final versions due: 31 October, 2017