Removal of Phenols in Table Olive Processing Wastewater by Using a Mixed Inoculum of Candida boidinii and Bacillus pumilus: Effects of Inoculation Dynamics, Temperature, pH, and Effluent Age on the Abatement Efficiency

The main goal of this paper was to assess the ability of a combination of Candida boidinii and Bacillus pumilus to remove phenol in table olive processing water, as a function of some variables, like temperature, pH, a dilution of waste and the order of inoculation of the two microorganisms. At this purpose C. boidinii and B. pumilus were sequentially inoculated in two types of table olive processing water (fresh wastewater, FTOPW and wastewater stored for 3 months-aged wastewater, ATOPW). pH (6 and 9), temperature (10 and 35 °C) and dilution ratio (0, 1:1) were combined through a 2k fractional design. Data were modeled using two different approaches: Multifactorial Analysis of Variance (MANOVA) and multiple regression. A higher removal yield was achieved by inoculating B. pumilus prior to the yeast (192 vs. 127 mg/L); moreover, an increased efficiency was gained at 35 °C (mean removal of 200 mg/L). The use of two statistic approach suggested a different weight of variables; temperature was a global variable, that is a factor able to affect the yield of the process in all conditions. On the other hand, an alkaline pH could increase the removal of phenol at 10 °C (25-43%).

Assessing biomass diversity and performance of an activated sludge process treating saline table olive processing wastewater

This study aimed to determine the effects of salinity on the biomass behavior and its diversity in activated sludge process (ASP) treating the table olive processing wastewater (TOPW), and to evaluate ASP performances under increased TOPW concentration feeding, the numerical abundance, diversity and activity of the biomass, removal efficiencies of chemical oxygen demand (COD), phenolic compounds, nitrogen and phosphorus were evaluated. Results showed that biomass growth is very high and became faster according to an increase in the percentage of TOPW feeding and reached 5.2 g_MLVSS l^-1. The specific oxygen uptake rate (SOUR) analysis revealed that salinity up to 10 g l^-1 provides an increase in biomass activity. SOUR reached a maximum of 20.3 g_O2 g_MLVSS^-1 h^-1. The increasing percentages of TOPW induce actually an evolution of microorganism's biodiversity; the microorganism communities were characterized by the abundance of halotolerant, Pseudomonas and Yeast genus that became the most abundant in the bioreactor as adaptation response against salinity. Furthermore, COD, phenolic compounds, nitrogen and phosphorus removal efficiencies attained 92.3%, 84.5%, 80% and 60%, respectively. A satisfactory release of extracellular polymeric substances is found to occur in the reactor with regard to increased saline TOPW, providing significant removal efficiencies and best settling of sludge.