L. Martínez Nieto

Kinetics of aerobic treatment of olive-mill wastewater (OMW) with Aspergillus terreus

A kinetic study was carried out on the aerobic treatment of olive-mill wastewater by fermentation with Aspergillus terreus. The bioreactor used was batch fed at several concentrations. The aerobic treatment process followed a Quiroga and Sales model, which is represented by a second-grade polynomial from which the kinetic constants; maximum substrate concentration (h), maximum specific growth rate (P) and organic matter present in the medium (q) were calculated by using a non-linear regression. The mean values for chemical oxygen demand (COD) elimination velocity were 126.3 mg l − 1 h − 1 in the first 24 h and 77.3 mg l − 1 h −1 at 72 h. An increase in airflow allowed higher degradation percentages in less time (COD: 65.77% and BOD: 85.41%). The kinetic parameters ‘q=S’, corresponds to the organic matter present in the medium, which cannot be metabolized by the microorganisms under operating conditions. The value of P =max was influenced by the transfer of pure oxygen, the value of c M (minimum cellular retention time) decreased from 22.42 h for air with a porous plate to 8.31 h for pure oxygen.

THE BIOLOGICAL PURIFICATION OF WASTE PRODUCTS FROM OLIVE OIL EXTRACTION

Aspergillus terreus gave the overall best results in alpechin at approximately 80% concentration, degrading organic material by 53%, expressed as COD, and 67%, expressed as BOD. Degradation of the total phenol content, which included the great majority of phenolic compounds, reached 69%.

Elimination of pesticide residues from virgin olive oil by ultraviolet light: preliminary results.

Virgin olive oil is one of the essential products for the economy of Mediterranean countries. The possible residues of pesticides that can reach the oil may be a risk to public health, thus causing the prohibition of its marketing by the health authorities. This paper is a preliminary study on photochemical degradation of pesticide residues using a small-scale prototype (1L capacity). The method presents an effective alternative for the complete photodegradation or reduction of these chemicals using ultraviolet light without harming the quality parameters of the virgin olive oil. The photodegradation yields have varied within the range 7-80% depending on the time and temperature applied.