Amruta Morone

Reduction of NOx in Fe-EDTA and Fe-NTA solutions by an enriched bacterial population

An enriched biomass was developed from municipal sewage sludge consisting of three dominant bacteria, representing the genera of Enterobacter, Citrobacter and Streptomyces. The biomass was used in a series of batch experiments in order to determine kinetic constants associated with biomass growth and NOx reduction in aqueous Ferrous EDTA/NTA solutions and Ferric EDTA/NTA solutions using ethanol as organic electron donor. The maximum specific reduction rates of NOx in Ferrous EDTA and Ferrous NTA solutions were 0.037 and 0.047mMolesL(-1)d(-1)mg(-1) biomass, respectively while in Ferric EDTA and Ferric NTA solutions were 0.022 and 0.024mMolesL(-1)d(-1)mg(-1) biomass, respectively. In case of Ferric EDTA/NTA solution, the kinetic constants associated with reduction of Ferric EDTA/NTA to Ferrous EDTA/NTA were also evaluated simultaneously. The maximum specific reduction rates of Ferric EDTA and Ferric NTA were 0.0021 and 0.0026mMolesL(-1)d(-1)mg(-1) biomass. The significance of these observations are presented and discussed in this paper.

Air-lift reactor system for the treatment of waste-gas-containing monochlorobenzene

An air-lift bioreactor (ALR) system, applied for the treatment of waste-gas-containing monochlorobenzene (MCB) was seeded with pure culture of Acinetobacter calcoaceticus, isolated from soil as a starter seed. It was found that MCB was biologically converted to chloride as chloride was mineralized in the ALR. After the built up of the biomass in the ALR, the reactor parameters which have major influence on the removal efficiency and elimination capacity were studied using response surface methodology. The data generated by running the reactor for 150 days at varying conditions were fed to the model with a target to obtain the removal efficiency above 95% and the elimination capacity greater than 60%. The data analysis indicated that inlet loading was the major parameter affecting the elimination capacity and removal efficiency of>95%. The reactor when operated at optimized conditions resulted in enhanced performance of the reactor.

Carbamazepine and oxcarbazepine removal in pharmaceutical wastewater treatment plant using a mass balance approach: A case study

The manufacturing of the antiepileptics, carbamazepine (CBZ) and oxcarbazepine (oxCBZ), results in generation of wastewater containing these micropollutants which exhibit toxicity even at trace levels. Therefore, we focused on monitoring their fate and removal in various units of a full-scale wastewater treatment plant (WWTP) using mass balance approach. An apparent CBZ removal of 50±3% was observed by conventional activated sludge process in the biological treatment unit, whereas oxCBZ still persisted after the biological treatment and showed negative mass balance. However, reverse osmosis resulted in 91% oxCBZ removal, whereas CBZ still continued to persist as a result of lower solubility of CBZ as compared to oxCBZ. Only 3% CBZ exhibited sorption onto the suspended solids and sludge, which was negligible for oxCBZ, thus demonstrating their tendency to remain in aqueous phase. Additionally, we attempted to understand the fundamental mechanism behind the removal of these pharmaceuticals and it was apparently the collective effect of sorption, mineralization, biotransformation, biodegradation, phototransformation/photodegradation, etc. Thus, the integrative data presented in the present study on productivity of these pharmaceuticals, their mass loading in influent and effluents allied with their removal efficiency will be significantly constructive in benchmarking the operational effectiveness through operational optimization and design improvement of the current conventional treatment plant.