Olive oil liquid wastes–Characteristics and treatments: A literature review

Abstract

Olive oil sector witnesses an important growth due to the health benefits related to the product. However, olive oil producing countries suffer from the considerable amount of wastewater generated at the end of the process. Olive oil wastewater is a powerful pollutant. The nature of this effluent is highly variable due to various factors that should be taken into consideration. Generally, the nature of this wastewater is oily and contains a high organic load and low biodegradability due to the high content of phenols. Currently, it is discarded in the majority of countries, especially with the absence of uniform legislation for its treatment and reuse. Thus, olive mill wastewater represents a severe environmental pollution problem. Various studies suggested different types of treatment to deal with olive mill wastewater. However a low-cost and effective treatment remains a challenge on the practical part. This review aims to highlight the olive oil production with a special interest in the physico-chemical and biological characteristics of all the types of olive liquid waste, from olive washing wastewater and olive mill wastewater. In addition, the variability in olive wastewater composition based on various factors has been explored. Finally, different treatments techniques tested and applied on olive liquid waste were documented. This work will allow researchers to easily understand the variability of olive liquid waste’s characteristics and factors to study when dealing with this effluent. Moreover, it will help researchers for a better knowledge related to olive liquid waste treatments and challenges faced.