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 gMLVSS.L-1 and a high microbial activity of 21.88 mg O2.gMLVSS-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.

Effect of polyphenols on activated sludge biomass during the treatment of highly diluted olive mill wastewaters: biomass dynamics and purifying performances.

This study aims to investigate the feasibility of treating olive mill waste water (OMWW) by activated sludge pilot (AS) after its high dilution (1%) by urban waste water (UWW) and to study the effect of polyphenol compounds on the biomass during the treatment. Specific oxygen uptake rate (SOUR), mixed liquor volatile suspended solids (MLVSS), chemical oxygen demand (COD) and total polyphenols, were followed up over 100 days. In spite of the polyphenols' high concentration (up to 128 mg·L-1), successful biomass growth of 7.12 g MLVSS.L -1 and activity were achieved. Most of the bacteria (Pseudomonas sp., Klebsiella oxytoca, Citrobacter fereundii, Escherichia coli and Staphylococcus sp.) and fungi (Trichoderma sp., Rhizopus sp., Aspergillus niger, Penicillium sp., Fusarium sp., Alternaria) identified in the aerobic basin during the stabilization stage were known to be resistant to OMWW and showed effective adaptation of the biomass to polyphenols in high concentration. COD and polyphenols were highly eliminated (90%, 92% respectively). The sludge volume index in the pilot settling tank was almost constant at around 120 mL.g -1. This suggests the possibility of managing OMWW by simple injection at a given percentage in already functioning conventional AS treating UWW.