Reuse of California Brine Olive Oil Processing Wastewater to Meet Zero Discharge Goal

Reuse of low strength municipal wastewater is becoming quite common and many technologies are available for that purpose. However, treatment and reuse/recycling of high strength industrial wastewater is still a challenge. In this paper we present some case studies with implemented integrated systems to achieve zero discharge goal.We will concentrate on the description of a wastewater recycling/reuse system that was implemented at an olive processor plant in California. Olive processing produces large amounts of high strength wastewater with significant amounts of suspended solids, oil and grease, dissolved organics and salts (brine and caustic). The integrated wastewater treatment system was installed to achieve a zero discharge goal. The integrated system included solid screens, chemical flocculation, centrifugal flotation, ultrafiltration, reverse osmosis, ozonization, carbon filters, chlorine dioxide disinfection and evaporation.The integrated system achieved the zero discharge goal. However, concentration ratios of ultrafiltration and reverse osmosis devices and maximum flows were lower than predicted from pilot studies. The cost of treatment was high ($20 per 1000 gallons of treated water). The reverse osmosis system required cleaning with chemicals several times a day and energy costs of running the system were high.In more recent installations, it is shown that more efficient integrated systems can be implemented to achieve zero discharge goals at similar food processing plants. A system that includes flocculation/flotation, anaerobic and aerobic bioreactors and, if needed, low pressure fouling resistant reverse osmosis for salt removal can achieve similar goals at much lower cost of treatment. However, initial installation costs of bioreactors are higher, particularly for high flow applications (100 gallons per minute or more).