Olive mill wastewater characteristics: modelling and statistical analysis

A synthesis of the work carried out on Olive Mill Wastewater (OMW) characterisation is given, covering articles published over the last 50 years. Data on OMW characterisation found in the literature are summarised and correlations between them and with phenolic compounds content are sought. This permits the characteristics of an OMW to be estimated from one simple measurement: the phenolic compounds concentration. A model based on OMW characterisations from 6 countries was developed along with a model for Portuguese OMW. The statistical analysis of the correlations obtained indicates that the Chemical Oxygen Demand of a given OMW is a second-degree polynomial function of its phenolic compounds concentration. Tests to evaluate the significance of regressions were carried out, based on multivariable ANOVA analysis, on visual standardised residuals distribution and their means for confidence levels of 95 and 99%, clearly validating these models. This modelling work will help in the future planning, operation and monitoring of an OMW treatment plant.