Eneliis Kattel

Ferrous ion-activated persulphate process for landfill leachate treatment: removal of organic load, phenolic micropollutants and nitrogen

ABSTRACT The innovative treatment technology based on sulphate radicals induced oxidation was applied for the treatment of landfill leachate. The performance of chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal in the Fe2+-activated persulphate system was moderate; however, the results of dissolved nitrogen (DN) and total phenols removal showed significant efficacy (≤39% and ≥87%, respectively). addition to the system enhanced the treatment efficacy and resulted in supplementary 15% of COD and 5% of DN removal. Hydroxyl radical-based H2O2/Fe2+ treatment of the landfill leachate was performed as well; the results indicated higher removal efficacy of COD and DOC compared to the system. However, practical application of the H2O2/Fe2+ system is considerably influenced by temperature rise and excessive foam formation. Generally, the ferrous ion-activated persulphate treatment could be a promising technology for ex situ as well as in situ landfill leachate treatment applications.

Hazardous waste landfill leachate treatment by combined chemical and biological techniques

AbstractThe efficacies of coagulation, ozonation, Fenton treatment, activated sludge process, Fenton treatment–activated sludge process (CHEM-BIO) and activated sludge process–Fenton treatment (BIO-CHEM) to treat hazardous waste landfill leachate were investigated and compared. The results of the biodegradability test revealed a high content of readily biodegradable organic matter in semicoke landfill leachate, and thus, aerobic biological oxidation was found to be a more reasonable and cost-effective technique for leachate treatment than direct chemical processes (ozonation, Fenton treatment). However, in terms of treatment efficacy, both chemical and biological processes resulted in a high residual organic load, indicating an insufficient leachate quality improvement. The treatment performance of the combined schemes (BIO-CHEM and CHEM-BIO) proved more effective and ensured the removal efficacy percentage met that required by EU legislation as well as the specific target discharge limits of the measured...

Treatment of high-strength wastewater by Fe2+-activated persulphate and hydrogen peroxide

Ferrous ion-activated persulphate and hydrogen peroxide were studied for the treatment of real high-strength industrial effluent. The Fenton process demonstrated greater organic load removal, biodegradability improvement and toxicity reduction as well as lower treatment cost than the activated persulphate system. However, the use of an activated persulphate process was more favourable due to the exothermic effect intrinsic to the Fenton reaction, which resulted in a rapid increase in the temperature of the high-strength wastewater along with excessive foam formation. Overall, for the H2O2/Fe2+ and processes, the application of a chemical oxygen demand (COD)/oxidant/Fe2+ weight ratio of 1/0.4/0.075 resulted in a COD removal of 58 and 50%, a 7-day biochemical oxygen demand/COD ratio increase from 0.14 to 0.3 and 0.23, and an increase in the EC50 (Daphnia magna) by 6.5-fold and 2.9-fold, respectively. The stepwise addition of the oxidant and activator was favourable for the Fenton process and resulted in negligible improvement in the wastewater treatment efficacy in the activated persulphate system.

Persulfate-based photodegradation of a beta-lactam antibiotic amoxicillin in various water matrices

ABSTRACT Amoxicillin (AMX), a widely used beta-lactam antibiotic, belongs to the World Health Organization’s list of essential medicines. This subsequently causes its long-term presence in the environment and therefore, affects different environmental compartments. In this research, the degradation and mineralisation of AMX by UVC-activated persulfate-based treatment in various aqueous media was assessed. The degradation of the target compound was in accordance with the pseudo-first-order reaction kinetics in all the UVC-induced systems. The results indicated that AMX degradation in any real water matrices is notably inhibited by the matrix properties. The trials with radical scavengers in ultrapure water proved the existence of and HO., but mainly contributed to the degradation of AMX in the UVC/ and UVC//Fe2+ systems. It was shown that the parent compound disappeared during the treatment, but the mineralisation extent referred to the formation of transformation products the main of which were identified. The findings of this study could provide valuable information about the elimination of beta-lactam antibiotics from various environmental and processed waters. GRAPHICAL ABSTRACT