Novel combined IME-O3/OH−/H2O2 process in application for mature landfill leachate treatment

In order to verify the feasibility of Fe/C microelectrolysis-Fenton oxidation for mature landfill leachate treatment in industrial application, this study conducted the treatment processes at full-scale by physicochemical and spectral characterization. The full-scale studies showed that 48.17% of the dissolved organic carbon (DOC) and 42.27% of the dissolved organic nitrogen (DON) were removed by the microelectrolysis-Fenton oxidation process, respectively. Spectra analysis further suggested that the mature leachate was mainly composed of tryptophan-like and fulvic-like compounds. The combination of microelectrolysis and Fenton oxidation efficiently decomposed the aromatic C=C into carboxyl-C and decreased the molecular size of DOC, resulting in a dramatic reduce (97.1%-98.3%) of the fluorescence intensity. The DON removal by microelectrolysis-Fenton oxidation likely associated with the NH2-decomposition of tryptophan-like and aromatic compounds into NO3-N. The tryptophan-like compounds may play a dominant role in Ba binding, while Pb and Cd were likely bound to both the tryptophan-like and fulvic-like compounds. Above 60% of the heavy metals were removed in the microelectrolysis-Fenton oxidation section. Results above confirmed the effectiveness of Fe/C microelectrolysis-Fenton oxidation for mature landfill leachate treatment in industrial application.

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Combining Coagulation and Electrocoagulation with UVA-LED Photo-Fenton to Improve the Efficiency and Reduce the Cost of Mature Landfill Leachate Treatment

Molecules ◽

10.3390/molecules26216425 ◽

2021 ◽

Vol 26 (21) ◽

pp. 6425

Author(s):

Javier Tejera ◽

Daphne Hermosilla ◽

Antonio Gascó ◽

Carlos Negro ◽

Ángeles Blanco

Keyword(s):

Landfill Leachate ◽

Treatment Cost ◽

Great Influence ◽

Leachate Treatment ◽

Dissolved Iron ◽

Pre Treatment ◽

Cost Efficient ◽

Mature Landfill Leachate ◽

Electro Coagulation ◽

Total Dissolved Iron

This study focused on the reduction of the treatment cost of mature landfill leachate (LL) by enhancing the coagulation pre-treatment before a UVA-LED photo-Fenton process. A more efficient advanced coagulation pretreatment was designed by combining conventional coagulation (CC) and electro-coagulation (EC). Regardless of the order in which the two coagulations were applied, the combination achieved more than 73% color removal, 80% COD removal, and 27% SUVA removal. However, the coagulation order had a great influence on both final pH and total dissolved iron, which were key parameters for the UVA-LED photo-Fenton post-treatment. CC (pH = 5; 2 g L−1 of FeCl36H2O) followed by EC (pH = 5; 10 mA cm−2) resulted in a pH of 6.4 and 100 mg L−1 of dissolved iron, whereas EC (pH = 4; 10 mA cm−2) followed by CC (pH = 6; 1 g L−1 FeCl36H2O) led to a final pH of 3.4 and 210 mg L−1 dissolved iron. This last combination was therefore considered better for the posterior photo-Fenton treatment. Results at the best cost-efficient [H2O2]:COD ratio of 1.063 showed a high treatment efficiency, namely the removal of 99% of the color, 89% of the COD, and 60% of the SUVA. Conductivity was reduced by 17%, and biodegradability increased to BOD5:COD = 0.40. With this proposed treatment, a final COD of only 453 mg O2 L−1 was obtained at a treatment cost of EUR 3.42 kg COD−1.

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