Nutrients' behavior and removal in an activated sludge system receiving Olive Mill Wastewater

This work aims to monitor inorganic nutrients (phosphorus and ammonium) behavior during the injection of Olive Mill Wastewater (OMWW) in an activated sludge process. The system was fed firstly with urban wastewater (UWW) and was alimented after its stabilization with OMWW (at 0.1% (v/v) and 1%) for 100 days. Total polyphenols, chemical oxygen demand (CODT), nutrients, and biomass behavior against OMWW injection were investigated. The results showed a satisfactory biomass growth of 7.12 g(MLVSS).L-1 and a high microbial activity of 21.88 mg O-2.g(MLVSS)(-1).h(-1). An overall removal reached 90%, 92%, 59% and 93% respectively for, CODT, total polyphenols, PO43- and NH4+. Adding OMWW at 1% seems to improve the nutrients elimination, especially phosphorus by the biological process probably though bringing more biodegradable organics. The chemical processes (precipitation/complexation) could also be involved in phosphorus removal, due to the OMWW wealth on salts elements such as calcium.

Automated summary

The study demonstrated that adding 1% OMWW in the activated sludge process improved the removal efficiency of nutrients, especially phosphorus. The presence of biodegradable organics in OMWW and possible involvement of chemical processes like precipitation/complexation contributed to the enhanced removal of phosphorus.