Dear All,

Can you please suggest any proven technology for reduction of TSS in the produced water (say from 400 mg/l down to 50 mg/l), which could operate on a continuous basis, e.g. washable filters? The problem is further complicated by the presence of dissolved oil. The size of particles is in a range of 2-15 microns.

Thanks beforehand,
Vagif

There are many technologies available, you have to first remove oil, and then plan of installing dual media filters and activated carbon filter

What residual oil content is acceptable, though approximately? Would you please provide some more details on these filters and their purpose !

Oil content should be below 5 ppm. Dual media filters and activated carbon filters are used to remove suspended solids down to below 10 ppm and there are several companies who can provide you these as a package if you provide them the flow rates and water analysis

Hello Vagif

The non-ferrous hydrometallurgical extractive industry has always had problems with suspended solids in the pregant liquor feed from solids leaching/solids separation to solvent extraction/other metal concentration stages where suspended solids result in crud formation, reduced plant perfromance and loss of valuable solvent.

In more recent years "pinned bed" clarifiers have been found to be superior to fixed bed filters which can struggle with high solids loadings. I came across the following article came from a very quick google search which gives an outline of the technology - you might find more relevant articles from a more focused search.

www.bateman.com/papers/Pinned%20Bed%20Paper%20Final.pdf

I have no direct experience of pinned bed clarifiers but have heard good reports from others who have.

Hope this helps your investigation

Kind regards

Mike Brooks

Filters will struggle with this level of solids even to bring down to the relatively high level indicated. I would examine coagulation and either
Dissolved Air Flotation (also good for oil)
Kruger Actiflo sand ballasted clarifier
Other ballasted clarifier variants

The ballasted clarifiers operate a a much higher rate by attaching the suspended matter to denser particles such as sand that settle out faster. The 'ballast' is then recycled threough a washing process to separate a sludge stream. Principal drawbacks are that the use a fair bit of energy and chemicals and in some designs the minimum available capacity is quite large.

You may want to check with a hydrocyclone company, if they can do it with particles so fine.

DAF-HRSCC-MGF/DMF, you can also look for option of ceramic( Silicon or titanium) membrane, which can take up some emulsified oil load (Up to 5%), no free oil though, which will replace DAF and HRSCC both. Check other impurities, ceramem compatibility with other impurities.

Use a centrifuge to seperate the oil from water.You have stated dissolved oil. Please not oil is not soluble in water and since it has a lower denssity rhan water it will float on the surface of water and the differential density perfectly suits centrifugal seperation of oil from water.Thereafter use a Reverse osmosis system to remove the TDS.Alternatively distill the water with oil suspension. the condensate will be free from oil as well as TDS

The use of dissolved air flotation system works well when the waste water is pH corrected. The solids and oil rise to the surface and are removed. Chemical addition introduced into the DAF can reduce total suspended solids in the waste water by up to 90% and reduce BOD through coagulation, it is important to remember for this to be effective the pH must be consistent. From past experience best results were obtained with pH 6.5 - 7.5

You say that pH is important for DGF operation. Is it due to addition of coagulants/flocculants? I.e they work well within certain pH range or...?