A bioflocculant-supported dissolved air flotation system for the removal of suspended solids, lipids and protein matter from poultry slaughterhouse wastewater.

In this study, two previously identified isolates, i.e. Comamonas aquatica (BF-3) and Bacillus sp. BF-2, were determined to be suitable candidates to utilise in a bioflocculant-supported dissolved air flotation (Bio-DAF) system as a pretreatment system for poultry slaughterhouse wastewater (PSW). A 2% (v/v) (bioflocculant:PSW) strategy was used for the DAF to reduce total suspended solids (TSS), lipids and proteins in the PSW, by supplementing the bioflocculants produced and the co-culture (C. aquatica BF-3 and Bacillus sp. BF-2) directly into the DAF. The Bio-DAF was able to reduce 91% TSS, 79% proteins and 93% lipids when the DAF system was operating at steady state, in comparison with a chemical DAF operated using 2% (v/v) alum that was able to only reduce 84% TSS, 71% proteins and 92% lipids. It was concluded that the Bio-DAF system worked efficiently for the removal of suspended solids, lipids and proteins, achieving better results than when alum was used.

Optimisation of bioflocculant production by a biofilm forming microorganism from poultry slaughterhouse wastewater for use in poultry wastewater treatment.

Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; moreover, the wastewater has microorganisms which can be harnessed to perform specific functions. Additionally, these microorganisms can grow either in planktonic (free floating) mode or sessile (attached) mode. This study focused on the optimisation of bioflocculant production by quantifying flocculation activity, determined using kaolin clay (4 g/L), by isolates prevalent in poultry slaughterhouse wastewater. Subsequent to their identification and characterisation, six bacterial strains were initially isolated from the poultry wastewater. Although all the isolated microorganisms produced bioflocculants under different conditions, i.e. pH and temperature, the strain that produced bioflocculants with a higher flocculation activity was isolate BF-3, a Comamonas sp., achieving a flocculation activity of 93.8% at 32.9 °C and pH 6.5. Fourier transform infrared spectroscopy (FTIR) analysis of the bioflocculant of the isolate, showed the presence of hydroxyl, carboxyl, alkane and amine functional groups, an indication that the bioflocculant was a protein constituent.