Insight on the biological treatability of dairy and beverage waste mixture using natural coagulation prior fermentation.

In both dairy and beverage industries, returned products are considered as waste and they are forwarded to the wastewater treatment plants (WWTP). Nevertheless, such products have an important organic load disturbing the WWTP performance. In this work, an upstream biological treatment for those products is proposed. Different mixture proportions of dairy and cola beverage waste (DW-B) were studied and their pollution loads were assessed. An equal volume mixture of cola beverage, source of phosphoric acid, with dairy waste allowed COD and turbidity reductions of 52% and 72%, respectively. Moringa oleifera seeds aqueous extract (10 g/L) has been incorporated (50%) as natural coagulant in the resulted mix DW-B₅₀. COD and turbidity abatement values reached 92% and 93%, respectively. The natural coagulation achieved better results compared to the chemical one using 10% of FeCl₃ solution (60 g/L) where the recorded abatement rate was 78% for COD. Then, the indigenous microflora in the mix was used for the biological treatment which reduced both COD (76%) and residual sugar (15%) contents. Nevertheless, the mixture inoculation using 1 and 3% of kefir grains improved sugar consumption rates to 58 and 73%, respectively. Such approach allows a better DW-B waste mixture treatability and milk proteins recovering for eventual valorization. [ABSTRACT FROM AUTHOR]