Treatment of Landfill Leachates with Combined Acidification/Coagulation and the Fe0/H2O2 Process

Abstract

One of the major environmental concerns associated with waste disposal is the large amount of generated landfill leachates (LL), which are considered a type of wastewater with a complex composition. There is an urgent need to find an effective LL treatment method. LL were subjected to pretreatment followed by the Fe0/H2O2 process. Pretreatment efficiency was coagulation at pH 6.0 >> coagulation at pH 9.0 > acidification at pH 3.0. Coagulation at pH 6.0 in an optimal Fe3+ dose of 1000 mg/L decreased total organic carbon (TOC) from the initial concentration of 1061 mg/L to 491 mg/L while acidification to pH 3.0 decreased TOC to 824 mg/L. After acidification, the Fe0/H2O2 process with 8000/9200 mg/L Fe0/H2O2 reagent doses decreased TOC to 499 mg/L after a processing time of 60 min. Performance of the Fe0/H2O2 process after coagulation at pH 6.0 for optimal Fe0/H2O2 8000/5540 mg/L reagent doses decreased TOC to 268 mg/L (75% TOC removal). Treatment of landfill leachates with combined process coagulation and Fe0/H2O2 also increased their susceptibility to biodegradation, expressed as the biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio from 0.13 to 0.43, allowing LL to be considered as susceptible to biodegradation. Fe0/H2O2 process kinetics was described. A statistical analysis confirmed the obtained results. The proposed method can be successfully applied for LL treatment.

Treatment of a Mature Landfill Leachate: Comparison between Homogeneous and Heterogeneous Photo-Fenton with Different Pretreatments

“…Amor et al (2015) [19] reported an increase in TOC removal from 54% with a single solar-photo-Fenton up to 75% using a coagulation pre-treatment with 2 g/L of FeCl 3 at pH = 5. Similarly, at pH = 3, Bogacki et al (2019) [38] achieved a total TOC removal of 75% combining coagulation with ferric chloride (1 g/L at pH = 6), and heterogeneous Fenton process (Fe 0 /H 2 O 2 = 1.4 ratio). However, a systematic comparison of coagulation with ferric chloride and alum as pretreatment for a photo-Fenton process has not been published yet.…”

“…Furthermore, the use of ZVI allows working at neutral pH and can be reused several cycles [34,37]. Due to the high consumption of energy and chemicals for the direct use of AOPs without any pretreatment, the combination of coagulation/flocculation and AOPs seems to be the best option to treat the mature landfill leachates [19,38]. Amor et al (2015) [19] reported an increase in TOC removal from 54% with a single solar-photo-Fenton up to 75% using a coagulation pre-treatment with 2 g/L of FeCl 3 at pH = 5.…”

Influence of Particle Size and Zeta Potential in Treating Highly Coloured Old Landfill Leachate by Tin Tetrachloride and Rubber Seed

“…Using 3 M hydrochloric acid (HCl) or 3 M sodium hydroxide, the pH of the samples was modified to the appropriate pH value (pH3–11) (NaOH). The acid and base used in this study were also used by other researchers, for example [ 29 , 30 ]. Then, using the pre-determined value of the operational condition, the leachate was agitated simultaneously.…”