General treatment of effluents

The oil separators located in the water treatment unit are equipped with oil collector drums. However, since there are no devices to scrape the bottoms, the sludge must periodically be removed. It may be centrifuged before it is disposed of outside the refinery. The flows to be treated collect in a 20,000 m tank kept only 50% full so it can serve as a surge tank. Then they are redistributed to purification at an average flow rate of 600 to 650 

Physicochemical purification includes flocculation (iron chlorosulfate and cationic polyelectrolyte) followed by flotation. 

Biological purification is performed in a trickling filter whose bed is filled with random plastic material (polypropylene rings measuring about 15 cm in a maximum volume of 2200 m ). SS separation is pursued in a secondary longitudinal settler. 

The facility is run based on in-line measurement of the TOC (on 100 xm filtered water) and turbidity at the DAF outlet. This gives a rapid assessment of trends. A common level for the TOC is 15 to 30 mg l and it can rise to 50 to 80 for short periods. 

Parameters DAF outlet (approx.) Secondary settler outlet (in 1989, 649 m -h )  

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