Aerobic pretreatment of olive oil mill wastewater using Ralstonia eutropha

Analysis of pharmaceuticals, hormones and bacterial communities in a municipal wastewater treatment plant - Comparison of parallel full-scale membrane bioreactor and activated sludge systems

In this study, the occurrence of pharmaceuticals, hormones and bacterial community structures was studied at a wastewater treatment plant in Finland having two different parallel treatment lines: conventional activated sludge (CAS) treatment with a sedimentation stage, and a membrane bioreactor (MBR). Influent and effluents were sampled seven times over a period of one year. The bacterial communities of the influent samples showed a high degree of similarity, except for the February sample which had substantially lower diversity. There was significant fluctuation in the species richness and diversity of the effluent samples, although both effluents showed a similar trend. A marked decrease in diversity was observed in effluents collected between August and November. The initiation of nitrogen removal as a result of an increase in temperature could explain the changes in microbial community structures. In overall terms, suspended solids, bacteria and total organic matter (COD and BOD) were removed to a greater extent using the MBR, while higher Tot-N, Tot-P and nitrate removal rates were achieved using the CAS treatment. Estrone (E1) concentrations were also consistently at a lower level in the MBR effluents (<0.1-0.68 ng/l) compared to the CAS effluents (1.1-12 ng/l). Due to the high variation in the concentrations of pharmaceuticals, no clear superiority of either process could be demonstrated with certainty. The study highlights the importance of long-term sampling campaigns to detect variations effectively.

Use of a packed-bed airlift reactor with net draft tube to study kinetics of naphthalene degradation by Ralstonia eutropha

Biodegradation of naphthalene by Ralstonia eutropha (also known as Cupriavidus necator) in a packed-bed airlift reactor with net draft tube (PBALR-nd) was studied; the Kissiris pieces were the packing material. The reactor hydrodynamics has been characterized under abiotic conditions and the dependencies of the superficial gas velocity (U G) on the gas holdup (εG), liquid mixing time, and mass transfer coefficient were determined. The improving role of the net draft tube in this small column reactor (height 42 cm, ID 5 cm) was confirmed. The flow regime was described using the εG α U G (n) expression, and bubbly flow was observed in PBALR-nd at U G < 2.83 cm/s. In the second step of the present work, the kinetics of biodegradation was modeled using the Haldane and Aiba equations. The fitting of the experimental results to the models were done according to the nonlinear least square regression technique. The biokinetic constants (q m, K s, and K i) were estimated and q m as the specific biodegradation rate was equaled to 0.415 and 0.24 mgnaph./mgcell h for the Haldane and Aiba equations, respectively. The goodness of fit reported as R (2) and root-mean-square error (RMSE) showed the adequate fitness of the Haldane and Aiba models in predicting naphthalene biodegradation kinetics. On the basis of the HPLC results, a hypothetical pathway for the biodegradation was presented.

Literature review on production process to obtain extra virgin olive oil enriched in bioactive compounds. Potential use of byproducts as alternative sources of polyphenols

This review describes the olive oil production process to obtain extra virgin olive oil (EVOO) enriched in polyphenol and byproducts generated as sources of antioxidants. EVOO is obtained exclusively by mechanical and physical processes including collecting, washing, and crushing of olives, malaxation of olive paste, centrifugation, storage, and filtration. The effect of each step is discussed to minimize losses of polyphenols from large quantities of wastes. Phenolic compounds including phenolic acids, alcohols, secoiridoids, lignans, and flavonoids are characterized in olive oil mill wastewater, olive pomace, storage byproducts, and filter cake. Different industrial pilot plant processes are developed to recover phenolic compounds from olive oil byproducts with antioxidant and bioactive properties. The technological information compiled in this review will help olive oil producers to improve EVOO quality and establish new processes to obtain valuable extracts enriched in polyphenols from byproducts with food ingredient applications.

Pilot-scale treatment of olive oil mill wastewater by physicochemical and advanced oxidation processes

The pilot-scale treatability of olive oil mill wastewater (OOMW) by physicochemical methods, ultrafiltration and advanced oxidation processes (AOPs) was investigated. Physicochemical methods (acid cracking, oil separation and coagulation-flocculation) showed high efficiency of chemical oxygen demand (COD) (85%), oil and grease (O&G) (> 97%), suspended solids (SS) (> 99%) and phenol (92%) removal from the OOMW. Ultrafiltration followed by physicochemical methods is effective in reducing the SS, O&G. The final permeate quality is found to be excellent with over 90% improvements in the COD and phenol parameters. AOPs (ozonation at a high pH, O3/UV, H2O2/UV, and O3/H2O2/UV) increased the removal efficiency and the O3/H2O2/UV combination among other AOPs studied in this paper was found to give the best results (> 99% removal for COD, > 99% removal for phenol and > 99% removal for total organic carbon). Pilot-scale treatment plant has been continuously operated on site for three years (3 months olive oil production campaign period of each year). The capital and operating costs of the applied treatment alternatives were also determined at the end of these seasons. The results obtained in this study have been patented for 7 years by the Turkish Patent Institute.

Microwave-enhanced Fenton-like system, Cu(II)/H2O2, for olive mill wastewater treatment

Olive mill wastewater (OMW) is a substantial pollutant not only because of its high organic matter content and recalcitrant compounds such as polyphenols, but also due to its high chemical oxygen demand and biological oxygen demand. Its degradation by means of hydroxyl radicals generated from microwave application in the presence of hydrogen peroxide and Cu(II) has been investigated. The optimal experimental conditions were found to be a microwave intensity of 680 W, the presence of Cu(II) and relatively concentrated hydrogen peroxide (12 mol L(-1)). In these conditions, discolouration of OMW reached 98.0 +/- 0.2% and phenolic compounds decreased to 81.8 +/- 0.2% of their initial concentration after 12 min microwave time. Fourier transform infrared analysis confirmed that microwave degradation of phenols by means of the Fenton-like system Cu(II)/H2O2 could be an efficient solution for the treatment of olive mill wastewater.

Catalytic behaviour and copper leaching of Cu0.10Zn0.90Al1.90Fe0.10O4 spinel for catalytic wet air oxidation of phenol

A Cu0.10Zn0.90Al1.90Fe0.10O4 spinel catalyst prepared by the sol-gel method was tested for catalytic wet air oxidation (CWAO) of phenol. The catalyst showed high activity for phenol degradation. During successive test at 170 degrees C, 100% phenol conversion and 95% chemical oxygen demand (COD) removal were observed. Results from scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) indicated that the catalyst structure remained unchanged during reaction. From the analysis of temperature programmed reduction (TPR), diffuse reflectance UV-Vis spectra (DR UV-Vis) and activity assay at basic solution pH, it can be suggested that the highly dispersed copper ions on the catalyst surface were almost completely dissolved into the reaction solution, whereas the tetra-coordinated copper ions were not only stable against leaching but also active towards phenol degradation.