The results obtained according to these calculations (Table2) indicate that the aerobic-anaerobic treatment of OMWW is economically feasible given that the period of Return of lnvestment(PRI) is 5.82 years three times less than the lifetime of the installation ln addition the rest of the economic variables under study showed satisfactory values namely the Net Present Value(NPV) 0.29 million and the lnternal Rate of Return (IRR) 15%