Toluene degradation by a water/silicone oil mixture for the design of two phase partitioning bioreactors

Toluene degradation performances were studied in a 10 L Two-Phase Partitioning Bioreactor(TPPB).The liquid phase consisted of a mixture of water and PDMS 50(Poly Di Methyl Siloxane,i.e.silicone oil,viscosity of 46 m Pa·s) in the volume ratio of 75%/25%.Two series of experiments were carried out:in the first,the reactor was sequentially supplied with toluene whereas in the second,toluene was continuously supplied.Activated sludge from the wastewater treatment plant of Beaurade(Rennes,France) was used at an initial concentration of 0.5 dry mass g·(mixture L)^(-1).The elimination capacity(EC) was investigated as well as the change in biomass concentration over time.Toluene biodegradation was very ef ficient(removal ef ficiency,RE=100%) for toluene flows ranging from 0.2 to 1.2 ml·h^(-1),corresponding to elimination capacities of up to 104 g·m^(-3)·h^(-1).For a toluene flow of 1.2 ml·h^(-1),the biomass concentration measured at the end of the experiment was 4.7 dry mass g·(mixture L)^(-1).The oxygen concentration in the liquid phase was clearly not a limiting factor in these operating conditions.Based on these results,an extrapolation leading to the design of a large-scale pilot TPPB can now be considered to study toluene degradation performances in industrial conditions.

Kinetic degradation of amoxicillin by using the electro-Fenton process in the presence of a graphite rods from used batteries

This study reports the removal of amoxicillin(AMX)in aqueous media using the electroFenton process in the presence of a graphite cathode recovered from used batteries.The impact of the relevant parameters on the electroFenton process,namely the applied current intensity,the temperature,the initial concentration of AMX and the initial concentration of ferrous ions were investigated.The results showed that the optimal values were:I=600 mA,T=25℃,[AMX]_(0)=0.082 mmol·L^( 1) and[Fe^(2+)]=1 mmol·L^(1),leading to 95%degradation and 74%mineralization.The model parameters of AMX mineralization were determined using nonlinear methods,showing that it follows a pseudosecondorder kinetic.The Energy consumption(EC)calculated under the optimal values was found to be 0.79 kWhg 1,which was of the same order of magnitude of those reported in other findings;while it is noteworthy that the electrodes used in our study are of a lower cost.

Biodegradation by bioaugmentation of dairy wastewater by fungal consortium on a bioreactor lab-scale and on a pilot-scale

A fungal consortium including Aspergillus niger, Mucor hiemalis and Galactomyces geotrichum was tested for the treatment of dairy wastewater. The bio-augmentation method was tested at lab-scale （4 L）, at pilot scale （110 L） and at an industrial scale in Wastewater Treatment Plants （WWTP）. The positive impact of fungal addition was confirmed when fungi was beforehand accelerated by pre-culture on whey （5 g/L lactose） or on the dairy effluent. Indeed, chemical oxygen demand （COD） removal yields increased from 55% to 75% for model medium, diluted milk. While after inoculation of an industrial biological tank from a dairy factory with the fungal consortium accelerated by pre-cultivation in a 1000 L pilot plant, the outlet COD values decreased from values above the standard one （100 mg/L） to values in the range of 50-70 mg/L. In addition, there was a clear impact of fungal addition on the ＇hard＇ or non-biodegradable COD owing to the significant reduction of the increase of the COD on BOD 5 ratio between the inlet and the outlet of the biological tank of WWTP. It was in the range of 451%-1111% before adding fungal consortium, and in the range of 257%-153% after bio-augmentation with fungi. An inoculated bioreactor with fungal consortium was developed at lab-scale and demonstrated successfully at pilot scale in WWTP.