Chemical Treatment and Enhancement of Bioavailability of Olive Mill Wastewater

In this research, the potential of chemical treatment of olive mill wastewater (OMW) using different compounds such as lime, potassium permanganate, hypochlorite, and Fenton's reagent has been investigated. The capability of these compounds to breakdown the carbonaceous content of OMW was tested at different concentration ratios and contact times using a batch system. Chemical oxygen demand (COD) was used as an indicator for the organic content of the OMW. The results showed that chemical treatment is an effective means of treating highly concentrated wastewater such as OMW. A COD removal of about 90% was obtained at permanganate:COD ratio of 1:25 and contact time of 25 minutes. Using Fenton's reaction, more than 93% COD removal was observed at COD:Fe ratio of 50:1, H2O2:Fe ratio of 10:1, and contact time of 10 minutes. The lowest COD removal was observed using sodium hypochlorite. It was possible to reduce the bioavailability indicator, COD/BOD 5 ratio, by 40 and 50% by treating the OMW with permanganate and Fenton's reagent, respectively. These results along with the short contact time required indicate that chemical treatment is an effective alternative to conventional biological treatment of highly concentrated OMW.