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Rapid technological advancements that employ various manufacturing processes have generated a wide spectrum of anthropogenic compounds, many of which generate municipal and/or hazardous waste. Disposal of such wastes have gone into landfills, as these are one of the most economically viable method of dispensation. Although fiscal mandates have been served, ecological concerns have arisen as a result of this practice. landfill disposal sites are subject to leachate generation, which might be followed by groundwater contamination, if not controlled. In keeping, attention has been focused on reversing the deterioration of aquatic and terrestrial environment through the collection and the treatment of leachate wastewater. As a cause of the magnitude of this problem, it has been necessary to explore methods that affect sufficiently but remain cost effective. Several alternatives have been developed; however, biological and physicochemical procedures have been widely used for treatment of leachates of diverse compositions, comprised of a variety of organic pollutants. While this particular method of treatment has been met with measurable success in terms of contamination removal, it has proven to be costly and technically challenging due to the special and temporal variability in leachate quantity and quality. Nevertheless, recirculation, despite the initial opposition, is, as yet, one of the best method available to manage modern landfills and treat their leachate. The benefits of leachate recirculation are explored here through modeling of the chemical oxygen demand (COD) and biological oxygen demand (BOD), and through a comparative presentations between the single pass and the recirculated leachates that are obtained from a full scale landfills. In this study, landfills leachate composition of BOD and COD are modeled as pseudo-first order kinetics, and the rates of disappearance of leachate contamination strength are estimated in terms of half-life concept. All data sets employed in the simulation were gathered ( and referenced) from full-scale landfill literature documentation. The results of this study confirmed the superiority of leachate recirculated landfills over single-pass leaching landfills.

ABSTRACT Supply of safe drinking water following disasters is essential for life support of the affected population. Recently, hurricane Katrina left New Orleans Louisiana, Biloxi Mississippi and several other Gulf Coast Cities without drinking water. There is a need to develop methods that can be easily mobilized and will consistently produce safe and aesthetically acceptable drinking water. Nanoparticles have been demonstrated to have remarkable adsorptive and catalytic properties. Enhancement in their reactivity can be attributed to very high surface areas, a unique morphology (many comer and edge sites), large porosities, and small crystallite sizes. Reactive naooparticles of metal oxides such as titania, zinc oxide and '- ceria exhibit remarkable abilities to reduce threats of highly toxic substances in water (Chjog, P., et al., 1999, Li, X.Z., et.al., 2000). They are effective at neutralizing a wide range of acids and toxic industrial chemicals with the added capability to mitigate chemical warfare agents. These materials may offer a substantial reactivity and capacity that is advantageous over competitive technologies, such as activated carbons. Depending on the need, the particles can be utilized in a dry powder, granular, slurry form, as well as incorporated within the membranes, which will result in an enhanced membrane surface that kills microorganism, chemically oxidizes organics and mitigates organic and biofouling on the membrane surface. Anatase Ti0 ₂ has both bactericidal and detoxifying (endotxin generated by E.Coli) capabilities. (Kikuchi, K., et.al., 1998). The coated film had different surface characteristic relative to the uncoated films in that the coated film was more hydrophilic, smoother and had a more neutral (less negative surface charge than the uncoated film. ii The solvent (water) mass transfer characteristics of the film were increased by TiO2 coating; however there was no significant differences in solute mass transfer between the TiO2 coated and·uncoated films as determined by mass transfer coefficients that were determined from flat sheet testing in a DI water and a surface water matrix. These results indicate that TiO2 nanoparticle coating of membranes does beneficially affect solute mass transfer diffusion controlled membrane processes by lower the energy required, and therefore the cost of operation of diffusion controlled membrane processes. Hence, more research is warranted for the determination of the beneficial effect of the coating of TiO2 nanoparticles on membrane films. Although the PEPA cell density measurements in the distilled water and surface water matrixes were somewhat contradictory, the HPC biofilm data decisively indicated that the TiO2 coating on the BW30LE films reduced biofilm growth, which indicates the TiO2 nanoparticles would reduce biofilm fouling in a membrane element containing BW30LE films.

Nonpoint source pollution from agricultural activities significantly impacts quality of receiving water bodies, including increases in stream sediments and nutrients, and occurrence of pesticides in both surface and ground water. Agricultural activities in the West Wellfield Interim Protection Area (WWIPA), located in West Dade County in South Florida, have potential to impact both the environmentally sensitive Everglades and Florida Bay, and the Biscayne aquifer. The Hydrological Simulation Program-Fortran (HSPF) has been used to simulate water and constituent transport in the WWIPA and to determine possible impacts. Surface runoff, groundwater recharge, and transport of sediments, nutrients and pesticides are simulated by this model. ARC/INFO Geographic Information Systems (GIS) is interfaced with HSPF to store, manage, and display data, and derive input parameters for the model. Results of HSPF simulations are also visually presented through GIS. A GIS user interface was developed for the study area. Menus were created through which the database can be queried to derive model parameters and to visually present results through maps. Model results show that sediments, nutrients and pesticides are present in surface runoff, and nutrients enter the ground water. Various model test runs were made to minimize pollution levels without hindering agricultural production. They include application of minimum required rates of fertilizers, replacement of fertilizers by sewage sludge, and the effect of future urbanization.

Adsorption experiments using both monosodium methanearsonate (MSMA) and its inorganic degradation by-product species As(+5), as sodium arsenate Na2AsO4, were conducted to evaluate the sorptivity of these constituents to various fractions of soil samples taken from the West Palm Beach Country Club. Adsorption data were analyzed with common isotherm equations (i.e., Linear, Freundlich, Langmuir) to determine Kd for each arsenic (As) species/soil fraction. Simulations using a one-dimensional pesticide transport model, PRZM 2.0, were completed to evaluate possible dissolved concentrations of arsenic at the water table interface under 8 different application scenarios for the soil profile found at the sample site. All contaminant/soil systems displayed a linear sorptivity relationship (R2 ranging from 0.8262 to 0.9779) with Kd values (units of L/g) ranging from 0.0102 to 0.2295. Results also indicate As(+5) had a higher affinity for the soil fractions than MSMA. PRZM-2.0 predicted concentrations of dissolved arsenic at the water table interface from 0.04 to 1018 ppb within 1 month from only 1 application. Florida's MCL for dissolved as in groundwaters is 50 ppb. It is recommended that the registration and use of MSMA be re-evaluated as it may impact ground water quality at golf courses or other sandy aquifer systems.