Reduction of sludge formed during a coagulation treatment of Ridomil Gold by means of non-thermal quenched plasma pre-treatment

Chemical coagulation and adsorption, despite many drawbacks, are actually the main techniques used for the removal of pollutants from aqueous solution; however, these techniques are becoming ineffective due to the exponential increase in the amount and complexity of discharged pollutants; thus, the sludge treatment process became a more complex challenge. The present study focuses on the way to reduce the quantity of sludge formed during the removal of Ridomil Gold, a widely used pesticide-fungicide in agriculture. Results revealed that pre-treatment of initial waste solution by the gliding arc (Glidarc), a source of non-thermal plasma, leads to a significant reduction of the sludge formed during the coagulation treatment. For a 20-min pre-treated effluent Glidarc followed by chemical coagulation, there was a reduction in the volume of sludge formed in the order of 90 and 80% for alum and ferric sulfate coagulants respectively without reducing the performance of pesticide removal. Therefore, there is a positive synergism between treatment by chemical coagulation and plasma treatment. These results suggest that the Glidarc can be an effective solution for the reduction of sludge obtained during treatment by coagulation.     

Degradation of palm oil refinery wastewaters by non-thermal gliding arc discharge at atmospheric pressure

The gliding electric discharge in humid air is a source of activated species forming (e.g. ^? OH, ^? NO and their derivatives H₂O₂, ONO₂H and NO₃H) which are present in a non-thermal plasma at atmospheric pressure. These species are able to degrade organic pollutants in palm oil refinery wastewaters (PORW). The increase in acidity (pH decrease), conductivity and total dissolved solids (TDS) and the decrease in the total organic carbon (TOC) of PORW samples exposed to the discharge are reported. More than 50 % TOC abatement is obtained for 15 min treatment in batch conditions with a laboratory reactor. The organic pollutants of PORW, i.e. mainly fatty acids are degraded according to a pseudo first-order reaction (k*?=?0.06 min^?1). Post discharge reactions are also observed after having switched off the discharge, which suggests that the pseudo first-order (k?≈?0.05 min^?1) degradation reactions should be attributed to the diffusion of soluble reactive species, e.g. H₂O₂ and ONOOH in the liquid target.     

Photo-Fenton oxidation of Orange G azo dye: process optimization and mineralization mechanism

Environmental Chemistry Letters - Textile effluents containing synthetic dyes are one of the most important sources of water pollution. Several dyes are toxic to the aquatic life and...     

Enhancement of sorption capacity of cocoa shell biomass modified with non-thermal plasma for removal of both cationic and anionic dyes from aqueous solution

Environmental Science and Pollution Research - Removal of cationic dye, Azur II, and anionic dye, Reactive Red 2 (RR-2) from aqueous solutions, has been successfully achieved by using a modified...