Degradation of the organic part of LANDFILL in along with rainwater percolation produces a polluted liquid named "LEACHATE", which poses a considerable hazard to the environment because of its toxic and hazardous compounds. In this research, the treatability of LEACHATE was investigated using combined anaerobic digesters. Each digester had an effective volume of 150 l, a flow rate of 10 l/d, and a HRT of 15 d working at a temperature of 31oC (mesophilic). The OLR applied to the system was gradually increased from 0.07 to 3.4 g/l.d in 5 steps. TCOD concentration was 48552-62150.4 mg/l and BOD5/COD ratio was more than 0.7 during the study period. At an OLR of 2.2 g/l.d, the total maximum COD removal efficiency achieved in both digesters was 93.59%. Not only did ammonia concentration not reduce in the anaerobic system but it increased. Ammonia concentrations at optimum OLR in the influent to the 1st and 2nd digesters were 721, 952, and 1054 mg/l, respectively. Maximum biogas production was 9.823 l/day in the 1st digester and 6.298 l/day in the 2nd digester, both of which occurred at an OLR of 3.4 g/l.d.

Organic and mineral compounds generated as products of waste mineralization within biological processes and accompanying physical and chemical processes are washed out by percolating rainwater through the deposit of wastes in LANDFILL and form LEACHATE that has created many health and environmental concerns. This study intended to determine the efficiency of reducing COD, BOD5, TS and color of Hamadan LANDFILL LEACHATE by using carbon nanotubes. Experiments were performed in batch reactor and changing effective factors such as pH, time and concentration of iron nanoparticles. The efficiency of carbon nanotubes were investigated using a statistical test, One-Way ANOVA software SPSS-12. Highest removal efficiency was at concentrations of 2500 mg/ L NZVI, pH=2.5 and 10 minutes reaction time, 58.23%, 12.5%, 66.87%, 80% for COD, BOD, TS and color, respectively. The project results showed high potential for carbon nanotubes into absorbing organic use for treatment or pretreatment of Hamadan LANDFILL LEACHATE.

Background and Objectives: Owing to the non-seperated municipal solid wastes the LEACHATE form in land fills contain high amounts of heavy metalls and toxic substances Hence, LEACHATE treatment is a serious problem. In order to design LEACHATE treatment and collection systems, estimation of quality and quantity of LEACHATE is of high necessity. Hydrologic Evaluation of LANDFILL Performance (HELP) Model was used to estimate LEACHATE generation in the lined LANDFILL cells for a variety of conditions. The HELP program is a quasi-two-dimensional hydrologic model for conducting water balance analysis of LANDFILLs, cover systems, and other solid waste containment facilities. In this paper HELP program is used to predict LEACHATE generating in Semnan LANDFILL after its operational life.Materials andMethods: HELPmodel useweather, soil and design data to estimate LEACHATE quantity.The meteorological data were obtained from semnan Atmospheric Data Centre. Soil mechanics examinations in the LANDFILL area were applied to achieve soil data. In addition, design parameters were based on Semnan LANDFILL design specifications. Semnan LANDFILL capacity is designed so as to accommodate municipal solid wastes generated during the next 25 years.Results: In this study result indicated that precipitation and evapotranspiration has the most influenced on LEACHATE generation increase and decrease, respectively.82% of annual precipitation isn.t percolated into Semnan LANDFILL due to evapotranspiration. HELP Model simulations were indicated that the maximum and average value of LEACHATE height above barrier layer is 36 and 3mm, respectively.Conclusion: Semnan LANDFILL is designed under minimum standard condition. Therefore, low height of LEACHATE generated is due to area weather. The precipitation amount is low while the evapotranspiration amount is high in this area. High evapotranspiration is due to high temperature and solar radiation in Semnan LANDFILL area. High evapotranspiration in the LANDFILL cap caused 14.2% of the precipitation to infiltrate into the wastes and became LEACHATE.

Advanced Oxidation Processes (AOPs) have been employed to degrade biorefractory organic matters. This study investigates the combination of classical Fenton reaction with electrochemical oxidation, the electro-Fenton process, for the treatment of semi aerobic LANDFILL LEACHATE, collected from Pulau Burung LANDFILL Site (PBLS), Penang, Malaysia. The investigation has been carried out in batch reactors with aluminum electrodes to establish the optimal treatment conditions. The effects of applied current, pH, reaction time, electrodes separation distance, H2O2/Fe2+ molar ratio, and H2O2 and Fe2+ concentrations, significant process parameters by themselves, have also been investigated. According to the obtained results, electro-Fenton process is very efficient for the treatment of LANDFILL LEACHATE. Optimum oxidation efficiency has been achieved when neither H2O2 nor Fe2+ are overdosed, so that the maximum amount of OH radicals is available for the oxidation of organic compounds. The highest COD and color removals have been 92% and 93%, respectively; obtained at initial pH=3, H2O2/Fe2+ molar ratio=1, applied current= 2A, treatment duration= 30 min, and electrodes separation distance= 3 cm. The current efficiency declines from 94% to 38% when the current rises from 0. 5A to 2A.

LANDFILL LEACHATE presents hardly treatable, highly complex and very toxic environmental effluent originated in the municipal solid waste degradation process. Although, numerous treatment methods were developed so far, none of them alone could achieve permissible limits of the primary pollutants to discharge into natural recipients. The current study aimed to develop and apply the process to treat LANDFILL LEACHATE by simultaneous application of electrochemical methods, ultrasound, electromagnetic field and ozonation to achieve the legal criteria for its discharge into natural recipient and minimize its adverse environmental impacts. For this purpose, old LANDFILL LEACHATE was taken from the Piskornica (Koprivnica, Croatia) sanitary LANDFILL. Prior to the treatment, the LEACHATE was supplemented with NaCl (2 g/L) and subjected to simultaneous treatment with stainless steel electrode plates, ultrasound and recirculation through electromagnetic field. After 45 minutes, stainless steel electrode plates were replaced by iron electrodes and treated for another 10 minutes followed by 15 minutes of the treatment with aluminum electrode plates. Ultrasound and recirculation through electromagnetic field were also applied during Fe and Al electrode treatment. Finally, the electrodes were removed and the suspension was mixed with ozone for another 30 minutes and allowed to settle for an hour. Following the combined treatment, the removal efficiency for the turbidity, color, suspended solids, ammonium, phosphates and heavy metals was 99% or higher, while the removal of COD was 97%. All the measured parameters in the treated LEACHATE were lower compared to upper permissible limit for discharge into natural recipient.

LANDFILL LEACHATEs and LEACHATE sediments were investigated in order to survey the discharge of uranium (U) from municipal solid waste (MSW) LANDFILLs and municipal solid waste incinerator (MSWI) bottom ash LANDFILLs. Concentrations of U in the LEACHATEs were as high as or higher than concentrations of Cd, a metal more often discussed when considering the environmental effects of LANDFILL LEACHATE. However, the U concentrations in LEACHATE were no greater than levels occurring naturally in water. The U concentrations in LEACHATE sediments were also the same as or lower than those reported in lake sediments around the world. Size charge fractionation of U in freshly sampled LEACHATE showed that the metal was present mainly as either non-labile dissolved complexes or free anions, which have intermediate to high mobility and eco-toxicity. This is in contrast to other heavy metals, such as Cd, which are generally particulate bound in LEACHATE. However, based on all the results of the investigations, it was concluded that leaching of U is not of major concern in MSW and MSWI bottom ash LANDFILLs.

In most countries, sanitary LANDFILLing is the common way to dispose municipal solid wastes. In the operations, LEACHATE treatment is a difficult and expensive process. Although, LEACHATE can be treated by biological processes, COD removal efficiency is usually low due to high ammonium ion content and the presence of toxic compounds such as metal ions. This experimental study was conducted to investigate the effect of coagulation–flocculation process on the Hamadan LANDFILL LEACHATE treatment in the city of Hamedan. Also the effects of different coagulants with various dosages and pH values in the removal of chemical oxygen demand (COD) and total suspended solids were studied. Results showed that the efficiency for COD removal by Poly Aluminum Chloride at pH=12 and 2500 mg/L of coagulant, by alum at pH=12 and 1000 mg/L of coagulant dose and by ferrous sulfate at pH=12 and 1500 mg/L of ferrous sulfate dose were 60%, 62.33% and 70.66%, respectively. Also results showed that, the efficiency for Total Suspended Solids removal by Poly Aluminum Chloride that was obtained at pH=12 and 2500mg/L concentration of Poly Aluminum Chloride, by alum at pH=2 and 1500 mg/L concentration of alum and by ferrous sulfate at pH=7 and 2500mg/L of ferrous sulfate, were 39.14% , 58.37% and 35.58%, respectively. Based on results of this study, the best coagulant for COD removal was ferrous sulfate and the physico-chemical process may be used as an effective pretreatment process, especially for young LEACHATE, prior to post-treatment (polishing) for partially stabilized LEACHATE.