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Importance of Combined Electrochemical Process Sequence and Electrode Arrangements: A Lab-scale Trial of Real Reverse Osmosis Landfill Leachate Concentrate
- Source :
- Water research. 192
- Publication Year :
- 2020
-
Abstract
- Reverse osmosis (RO) is a widely applied technique for wastewater effluent reuse and landfill leachate treatment. The latter generates a refractory RO leachate concentrate (ROLC), for which cost-effective treatment is required. This study focuses on a two-step electrochemical method consisting of aluminum-based electrocoagulation (EC), and simultaneous electrooxidation-electrocoagulation with a titanium-based lead dioxide (Ti/s-PbO2) anode and aluminum cathode (EOEC) assembly. The sequence and electrode arrangements of the combined electrochemical process were investigated to determine the organic transformation, Ti/s-PbO2 anode viability, and energy consumption. Series-based EC-EOEC decreased the total chemical oxygen demand (COD) from 8750 mg L−1 to 380 mg L−1, a 96% removal efficiency, in 3.5 hours at 141 A m−2. Under a low energy consumption of 28.7 kWh kgCOD−1, the ROLC biodegradability (BOD5/COD) significantly increased from 0.015 to 0.530, which was ascribed to aromatic removal (e.g., -C=C) and an increase in -COOH functional groups. Furthermore, the rapid removal of natural organic matter and increase in pH elevation from EC suppressed the dissolution of Pb from the Ti/s-PbO2 anode during the subsequent EOEC, thereby leaving 0.061 mg L−1 in the ROLC after treatment. The treatment cost was 3.86 USD kgCOD−1, which was approximately 34% lower than that of previously reported electrochemical processes for ROLC treatment. These findings obtained with a real RO concentrate provide a foundation for scaling up this new electrochemical treatment approach.
- Subjects :
- Osmosis
Environmental Engineering
medicine.medical_treatment
0208 environmental biotechnology
02 engineering and technology
010501 environmental sciences
01 natural sciences
Electrocoagulation
PH elevation
medicine
Leachate
Reverse osmosis
Waste Management and Disposal
Effluent
Electrodes
0105 earth and related environmental sciences
Water Science and Technology
Civil and Structural Engineering
Biological Oxygen Demand Analysis
Chemistry
Ecological Modeling
Chemical oxygen demand
Pollution
020801 environmental engineering
Anode
Wastewater
Oxidation-Reduction
Filtration
Water Pollutants, Chemical
Nuclear chemistry
Subjects
Details
- ISSN :
- 18792448
- Volume :
- 192
- Database :
- OpenAIRE
- Journal :
- Water research
- Accession number :
- edsair.doi.dedup.....e82d652c099866dfb9195030a26be297