Electrochemical process for the treatment of landfill leachate

Abstract

In this paper, the anodic oxidation of a real leachate from an old municipal solid waste landfill has been studied using an electrolytic flow cell equipped with a lead dioxide (PbO 2 ) anode and stainless steel as the cathode. The influence of several operation parameters such as (i) the applied current (from 0.5 to 3 A), (ii) liquid flow rate (from 50 to 420 L h -1 ), (iii) temperature (from 25 to 50°C), and (iv) pH (from 3.5 to 8.2) on the COD removal rate, current efficiency, and energy consumption has been evaluated. The galvanostatic electrolyses always yielded COD values below the discharge limit (COD \160 mg L -1 ); the COD removal rate increased with rising applied current, solution pH, and temperature, whereas it remained almost unaffected by the recirculation flow rate. These results indicate that the organic compounds were mainly removed by their indirect oxidation by the active chlorine generated from chlorides oxidation. The specific energy consumption necessary to reduce the organic load to below the disposal limit was 90 kWh m -3 .

Combined Treatment of Old Sanitary Landfill Leachate

“…Compared to the current study results, somewhat lower removal efficiencies of COD (60% to 92%) were obtained by other researchers using electrooxidation methods (8)(9)(10)(11)(12)(13). By applying electrooxidation process, 92% of the COD and 100% of ammonium was removed from the old landfill leachate using titanium anode coated with Sn-PdRu oxides (8).…”

Sustainable treatment of landfill leachate

“…= 104, pH = 6.5, reaction temperature = 30 ± 1°C, reaction time = 300 min, number of stepwise addition = 7. Panizza et al (2010) utilized anodic oxidation using electrolyte flow cell equipped with lead dioxide (PbO 2 ) anode and stainless steel as cathode. They observed that the galvanostatic electrolyses enhanced COD removal along with rising current, solution pH and temperature.…”

Study on treating old landfill leachate by Ultrasound–Fenton oxidation combined with MAP chemical precipitation

“…[3,6] Leachates are mainly generated by (i) the natural precipitation and runoff in landfill site, (ii) the original water in the wastes, and (iii) decomposition processes occurring in the wastes. [7] The natural precipitation and runoff in landfill site are the main sources of leachate. It is a specific type of wastewater with a complex composition, containing large amounts of organic pollutants, ammonia nitrogen, inorganic salts, and heavy metals, and so on.…”

“…[2,9] The old landfill leachate (i.e., >10 years old) contains biorefractory compounds such as humic and fulvic acids, and is characterized by a low chemical oxygen demand (COD < 4000 mg L −1 ) and biological oxygen demand/ chemical oxygen demand ratio (BOD/COD < 0.1), so it is a kind of refractory and high concentrated organic wastewater. [7,10] At present, the treatments of landfill leachate are mainly physical-chemical method and biological method. [3] Because of their high cost-effectiveness and simplicity, biological treatments such as activated sludge, aerated lagoons, sequencing batch reactors, and upflow anaerobic sludge blanket reactors are widely and effectively used to treat the young leachate.…”

“…[2] However, it is difficult to remove COD from old landfill leachate with these conventional biological treatments, due to the low BOD/COD ratio (<0.1) and the presence of bio-refractory and toxic contaminants. [7,10] Simultaneously, owing to the potential risks posed by landfill leachates to aquatic ecosystems, especially ground water, the enforcement of environmental rules and regulations OPEN ACCESS to remove COD and ammonia nitrogen from the old landfill leachate, which collected from one sanitary landfills in Wuhan. The property of landfill in this experiment is that the COD concentration and ammonia nitrogen concentration are 800-900 mg L −1 and 900-1200 mg L −1 , respectively.…”