Abstract:-This study presents the results of a mature landfill leachate treated by a homogeneous catalytic ozonation process with ions Fe 2+ and Fe 3+ at acidic pH. Quality assessments were performed using Taguchi's method (L 8 design). Strong synergism was observed statistically between molecular ozone and ferric ions, pointing to their catalytic effect on OH
“…This can be explained by competition between different species of Fe 2+ ions and hydroxyl radicals (Equations (5)–(7)). A similar behavior was observed by Peixoto and Filho, [ 20 ] when studying the degradation of organic compounds in wastewater. Those authors found the optimal experimental conditions to be a high level of O 3 (0.6 g O 3 h –1 ) and low Fe 2+ (5 mg L –1 ).…”
Given the issue of lipids in effluent treatment systems and their negative impact on the environment, this study aimed to examine lipid degradation by homogenous catalytic ozonation with the aid of iron and manganese ions. This technology presents the possibility of completely mineralizing pollutants using hydroxyl radicals. Milk is chosen as the lipid source because of the high concentration of triglycerides in its matrix, this kind of lipid being the one found most frequently in food and, consequently, in effluent treatment systems. The milk pH value is controlled, and acidic, neutral, and basic conditions are evaluated. The rates of pseudo-first-order reactions and the effective value are estimated. It is shown that under acidic conditions low catalyst dosages are enough to cause the complete degradation of lipids. Under neutral conditions, a similar behavior is observed. Under basic conditions, higher catalyst dosages give higher reaction rates. The order of effectiveness of the catalysts under acidic and basic conditions is Fe 2+ > Mn 2+ , with Mn 2+ > Fe 2+ under neutral conditions. Homogeneous catalytic ozonation is therefore efficient at lipid degradation. This technique is viable economically, since the lipid removal occurred at low ozone levels. In addition, the ions used as catalysts are naturally abundant.
“…This can be explained by competition between different species of Fe 2+ ions and hydroxyl radicals (Equations (5)–(7)). A similar behavior was observed by Peixoto and Filho, [ 20 ] when studying the degradation of organic compounds in wastewater. Those authors found the optimal experimental conditions to be a high level of O 3 (0.6 g O 3 h –1 ) and low Fe 2+ (5 mg L –1 ).…”
Given the issue of lipids in effluent treatment systems and their negative impact on the environment, this study aimed to examine lipid degradation by homogenous catalytic ozonation with the aid of iron and manganese ions. This technology presents the possibility of completely mineralizing pollutants using hydroxyl radicals. Milk is chosen as the lipid source because of the high concentration of triglycerides in its matrix, this kind of lipid being the one found most frequently in food and, consequently, in effluent treatment systems. The milk pH value is controlled, and acidic, neutral, and basic conditions are evaluated. The rates of pseudo-first-order reactions and the effective value are estimated. It is shown that under acidic conditions low catalyst dosages are enough to cause the complete degradation of lipids. Under neutral conditions, a similar behavior is observed. Under basic conditions, higher catalyst dosages give higher reaction rates. The order of effectiveness of the catalysts under acidic and basic conditions is Fe 2+ > Mn 2+ , with Mn 2+ > Fe 2+ under neutral conditions. Homogeneous catalytic ozonation is therefore efficient at lipid degradation. This technique is viable economically, since the lipid removal occurred at low ozone levels. In addition, the ions used as catalysts are naturally abundant.
“…Leachate is classified as stabilized (mature), intermediate, or fresh (young) given BOD 5 /COD values of <0.2, 0.2-0.5, and >0.5, respectively (Robinson et al, 1983;Sun et al, 2010;Pilli et al, 2011). Some methods have been reported for the removal organics from landfill, such as biological treatment (aerobic, anaerobic and anoxic processes), physical methods (sedimentation, air stripping, adsorption, and membrane filtration) (Çeçen et al, 2003;Dehghani et al, 2007) and chemical methods (chemical precipitation (Lim et al, 2009;Kettunen et al, 1996), chemical oxidation (Zhao et al, 2010;Kurniawan et al, 2006), reverse osmosis, granular activated carbon (Peixoto et al, 2010), ion exchange R E T R…”
-Landfill leachate is one of the most important sources of toxic organic compounds for ground and surface waters. Advanced oxidation processes can offer an effective and environmentally friendly method for pretreatment of landfill leachates. In this study, an ultrasonic process was used for the pre-treatment of landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of the BOD 5 /COD ratio, up to a value compatible with biological treatment. Under optimized experimental conditions (pH of 10, power of 110 watts, frequency of 60 kHz, TiO 2 concentration of 5 mg/L and exposure time of 120 min), this method showed suitability for partial removal of chemical oxygen demand (COD). The biodegradability was significantly improved (BOD 5 /COD increased from 0.210 to 0.786) which allowed an almost total removal of COD by a sequential activated sludge process.
“…Scaling agent may absorb UV light or block penetration of UV light during the oxidation process, hindering the photolysis process and / or decreasing the production of ÁOH (Ghaly et al, 2001). Some examples of the compounds that absorb UV radiation are humic and fulvic acids (Peixoto and Filho, 2010), iron (200-400 nm), nitrate (230-240 nm), nitrite (300-310 nm), etc. (NWRI, 2000).…”
Section: Phasementioning
confidence: 99%
“…Physical-chemical and biological treatment are the common methods for landfill leachate treatment (Anfruns et al, 2013;Wu et al, 2004), especially the latter which is widely practiced due to its easy operation and low cost. However, the major drawback of biological treatment is that it is easily inhibited by toxic and recalcitrant compounds in landfill leachate, such as XOC and humic acids (Wang et al, 2012;Peixoto and Filho, 2010;Atmaca, 2009;Kim et al, 2001). Various authors also reported that biological treatment is only effective on immature leachate which has high biodegradability (Zhang et al, 2013;Wang et al, 2008;Kurniawan et al, 2006a).…”
Advanced oxidation processes (AOPs) are of special interest in treating landfill leachate as they are the most promising procedures to degrade recalcitrant compounds and improve the biodegradability of wastewater. This paper aims to refresh the information base of AOPs and to discover the research gaps of AOPs in landfill leachate treatment. A brief overview of mechanisms involving in AOPs including ozone-based AOPs, hydrogen peroxide-based AOPs and persulfate-based AOPs are presented, and the parameters affecting AOPs are elaborated. Particularly, the advancement of AOPs in landfill leachate treatment is compared and discussed. Landfill leachate characterization prior to method selection and method optimization prior to treatment are necessary, as the performance and practicability of AOPs are influenced by leachate matrixes and treatment cost. More studies concerning the scavenging effects of leachate matrixes towards AOPs, as well as the persulfate-based AOPs in landfill leachate treatment, are necessary in the future.
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