Estimation of Gas Emissions using the LandGEM Model from the Landfill of Baft County, Kerman, Iran.

Over time, waste buried in landfills produces greenhouse gases (GHG) such as methane (CH4) and carbon dioxide (CO2). It is essential to know and investigate the type and amount of production of these gases from landfills as well as their effects, considering the environment's vulnerability to GHG. In the present study, the gases released from the landfill of Baft county were estimated using the landfill gas emissions model (LandGEM). CH4 production rate (k) and potential CH4 generation capacity (Lo) considering the semi-arid area for Baft county were considered 0.05 year-1 and 170 m3/Mg, respectively. According to the results, in 2054, an amount of 18703819 Mg/year of waste enters the landfill of Baft county. The emissions of landfill gases (LFG), including total landfill gas, CH4, and CO2, remained relatively constant between 2004 and 2044, followed by a period of increasing emissions until 2054. However, from that point onward, there was a decline in gas emissions that continued until 2144. In 2054, the estimated emissions for total landfill gas, CH4, CO2, and non-methane organic compounds (NMOC) are projected to be 3.043E + 05, 8.128E + 04, 2.230E + 05, and 3.493E + 03 Mg/year, respectively. Similarly, in 2144, the estimated emissions for total landfill gas, CH4, CO2, and NMOCs are projected to be 3.380E+03, 9.029E+02, 2.477E+03, and 3.881E+01 Mg/year, respectively. The potential to generate 18.25 MWh/year of electricity exists for the Baft county landfill in 2054. The study showed that a significant amount of CH4 and CO2 gases would be discharged into the atmosphere from the landfill site of Baft county, which can be recycled to help produce energy and improve air quality.

Advanced oxidation processes for phthalate esters removal in aqueous solution: a systematic review.

This study addresses a systematic review of the scientific literature to evaluate the most common advanced oxidation processes (AOP) for the removal of phthalate esters (PE) in aqueous matrices. Six AOP were reviewed for PE degradation such as processes based on photolysis, Fenton, ozonation and sulfate radicals ( SO 4 • - ), combined AOP and other processes. The PE degradation efficiencies by AOP processes ranged from 40.3 to 100%. In the reviewed literature, an initial PE concentration within 0.04-250 mg/L was applied. The H2O2 concentrations used in the UV/H2O2 process and O3 concentrations in ozonation-based processes ranged between 0.85-1,360.6 mg/L and 2-4,971 mg/L, respectively. Based on the reported results, the PE oxidation data fit well to the pseudo-first order kinetic model. A review of the studies revealed that many oxidant species are produced in the AOP, including hydroxyl radicals (•OH), SO 4 • - , superoxide radical anions ( O 2 - • ), hydroperoxyl radicals (HO2 •), hydrogen peroxide (H2O2), and singlet oxygen (O2). Among these oxidants, •OH play a key role in the degradation of PE. However, SO 4 • - are more effective and efficient than •OH since SO 4 • - has a higher oxidation power (E = 2.5-3.1 V) compared to •OH radicals (E = 1.8-2.7 V). In different AOP processes, the aromatic rings of PE are destroyed by •OH and produce intermediates such as phthalic acid (C6H4(CO2H)2), benzoic acid ethyl ester (C9H10O2), 2, 5-dihydroxybenzoic acid (C7H6O4), formic acid (CH2O2), acetic acid (CH3COOH), and oxalic acid (C2H2O4), among some others. Until now, limited data have been reported on PE toxicity assessment. The reviewed literature has shown that AOP can be used effectively to degrade PE from aqueous matrices. However, this systematic study suggests focusing more on the evaluation of the toxicity of the effluent resulting from AOP for the decomposition of PE in future studies.