Table Olives Processing Wastewater Treatment With Application Of The GACS Method Of Zeologic S.A.


General Information
Wastewater produced from table olives production, contain both solid and liquid components. The ratio of oil, water and solid components, depends mainly from raw materials, processing technology and the type of the final product. Maturing stage affects significantly the composition of product and waste. Usually an olive with 8,4g weight contains 7g of water, 0,57g of oil, 0,47g of carbohydrates, 0,2g of fiber, 0,08g of proteins, 0,083g of inorganic salt and 0,03g of vitamins. Water content is reduced during maturing (from green to black olive) up to 2g while oil content is increasing. Water from grinded olives contains inorganic components, like nitrogen, iron, potassium and organic components as well, such as sugars, organic acids, pectin and polyphenols. All these components are increasing the wastewater’s organic load, which results in the fact that conventional wastewater treatment plants based on biological methods can’t be adequate for removing all the pollutants from this type of wastewater.
COD values of 8.000-23.000 mg/lit and BOD values of 2.000 – 9.000 mg/lit are not rare in wastewater produces from olive processing. It is noteworthy that in a conventional urban wastewater treatment plant the COD and BOD fluctuate between 400 and 800 mg/lit. Also the main wastewater production from olive processing focuses on a short period of time during the year (from November until February).
The main characteristics olive processing wastewater are presented on table 1.
Table 1. Olive processing wastewater characteristics
Characteristic Value Range
Ph 3,4 - 12
Conductivity (mS/cm) 23 - 146
Turbidity (NTU) 100 - 440
TOC (mg/lit) 480 – 2.700
Polyphenols (mg /lit) 192 – 3.000
COD (mg/lit) 8.600 – 23.000
BOD (mg/lit) 2.400 – 9.000
Total sugars (mg/lit) 480 – 1.100