Refuse and refuse disposal

An analytical investigation was conducted to evaluate the geotechnical safety and
stability of MSW landfills constructed with significantly steepened slopes achieved
through geosynthetic reinforcement. The primary motivation for this endeavor was to
propose a new design/construction methodology for innovative expansion of landfill
capacity. A 2-D plane strain linear elastic analysis was performed with ANSYS finite
element software on full-scale MSW landfill structures (with and without geogrids),
having slopes of 1:1, 1:2, and 1:3. Both local and global factors of safety were
determined employing the Mohr-Coulomb failure criteria, and compared with traditional
solutions using the Bishop's Modified Method. It was found that the landfill slopes could
be steepened up to 1:1 using geogrid reinforcement, resulting in higher storage capacity
and consequential environmental and economic benefits.

Since the United States Environmental Protection Agency (USEPA) began requiring landfills to implement a leachate collection system in 1991, the proper disposal of leachate has become a growing concern. The potential toxicity of landfill leachate will contaminate groundwater and soil if not managed properly. Research has been made in efforts to manage leachate in a cost-effective, single treatment process. Photocatalytic oxidation is an advanced oxidation process (AOP) which has shown ability to reduce toxicity of an array of leachate constituents including organics, inorganics and heavy metals. The purpose of this manuscript is to scale up the batch scale study of TiO2 photocatalytic degradation of leachate utilizing a pilot scale falling film reactor. In this research project, the use of UV/TiO2 for the removal of chemical oxygen demand (COD), ammonia, alkalinity and color will be studied in order to optimize catalyst dosage, determine pH effects and reaction kinetics and develop preliminary cost estimates.

A landfill is in a reserved space on land used for the disposal of refuse by utilizing the principles of engineering to confine the refuse to the smallest practical area to prevent the creation of nuisances to public health or safety (Andersen et al. 1967). However, because landfills are open to the atmosphere, rainfall can saturate them, resulting in a liquid called leachate. Leachate generated within the landfill contains suspended solids, soluble components of the waste and by-products from the degradation of the waste by various micro-organisms. Treatment of leachate is an emerging area of need. In this manuscript the main purpose is to investigate a laboratory scale batch reactor that is able to detoxify and treat leachate by using an advanced oxidation process (i.e. TiO2). Based on the results obtained from this ground breaking research, it appears that the process investigate has the potential to radically change the way landfill leachate is treated. Scale up may provide direction that can be used to improve the efficiency of the different stages of toxicity of leachate during the entire life of a landfill.