Water and Wastewater.com Help Forums - DAF oil and grease removal %

Hennessy Ex Member	DAF oil and grease removal % Dec 01^st, 2009, 1:42pm I'm going to be sending out a sample to a certified lab for Oil and Grease before and after our DAF unit. I'm wondering if anyone has any info for what is considered good removal %. I'm not sure what the initial O & G concentration is but it is for dairy wastewater. thanks, any help is much appreciated
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Dan Keys

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Re: DAF oil and grease removal %
Reply #1 - Dec 1^st, 2009, 5:24pm

Good afternoon!

A well run DAF with proper chemistry can be expected to remove greater than 95% of Oil and Grease content. It will also remove about 90% of the suspended solids in the water.

If the DAF is run without chemistry, it will remove only "free" fats and oils, that is, oils that are not emulsified or suspended by surfactants. In dairy processing, most of the fats are in an emulsified state naturally. That's why you have to use a churn to make butter Wink

So, don't expect more than about 20% removal of fats and oils without the use of chemicals in a DAF treating dairy processing water.

Let me know if you have any further questions.

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Jeff Naumann

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Re: DAF oil and grease removal %
Reply #2 - Dec 10^th, 2009, 1:03pm

And, the removal percentage will depend upon the influent O&G concentration. In other words, you can get the 95% that Dan quotes if the influent O&G is fairly high, say 100 mg/l or higher; but, if the influent concentration is only 20 mg/l you won't be able to achieve more than say 75%. At least that's my experience in the tuna industry.

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Hennessy Ex Member	Re: DAF oil and grease removal % Reply #3 - Dec 10^th, 2009, 3:45pm Dan- I got the lab results back for the O&G analysis and you were right on the money ;24% reduction. Now I've got something to present to the client and hopefully get the ball rolling on our chemical program- hope to contact you soon!
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Dan Keys Senior Member Offline Dissolved Air Flotation Specialist Posts: 318 Florida, USA Gender: Company or Organization: KeysTec Environmental, Inc.	Re: DAF oil and grease removal % Reply #4 - Dec 10^th, 2009, 9:36pm I completely agree about the percentage of reduction when the influent O&G levels are very low. Of course, in a dairy application, O&G can be quite high. By the way, WELCOME to the forum, Jeff. I look forward to your input.
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Jeff Naumann God Member Offline I love Water and Wastewater.com Posts: 1133 Torrance, California Gender: Company or Organization: Jeff Naumann & Associates	Re: DAF oil and grease removal % Reply #5 - Dec 11^th, 2009, 2:41pm Thanks for the welcome, Dan. BTW, do you know Roy Carawan at NC State? We used to attend the same annual junket back in the 1980's.
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Dan Keys

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Re: DAF oil and grease removal %
Reply #6 - Dec 11^th, 2009, 4:16pm

Yes. It's been awhile. Roy Carawan has had a prolific input to waste water treatment of food industry effluents. He did significant work in the development of chitosan, a natural polymer derrived from shrimp shells at the same time I was working on natural polymers derrived from seaweed for use in the food processing industry. He, Wayne Bough Brian Sheldon and Bill Merka, all of NC State Extension, were very active in specialised wastewater treatment and water re-use.

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Jeff Naumann

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Re: DAF oil and grease removal %
Reply #7 - Dec 11^th, 2009, 4:23pm

I remember Wayne Bough, also. I vaguely recall that he went to Mid-America Dairy in that time frame.

I miss going to that annual meeting for "Environmental Engineering in The Food Industry." I wonder if they still have it?

I chitosan actually being used? I recall Roy and Wayne were always talking about it. In those days my main worry was getting rid of zillions of gallons of stinky tuna cannery sludge.

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Re: DAF oil and grease removal %
Reply #8 - Jan 16^th, 2011, 2:35am

Hi prf'ls,
it is being of very much interesting to me when i see the DAF,i would like to share my problim in the waterproofing industry,a mixture of chemicals in the generation water to treat.
Most of the chemicals which may be presesnt in the water :
Bitumen oils/Low molecular weight bitumens (containing mercaptans)
Lube oil
Caustic soda
Detergent
Cement filler dust
Polypropylene dust and fibres
SBS rubber dust
Small traces of chemicals (Soda Ash, phthalic anhydride, maleic anhydride.)
we merely require the water purity to be good enough to recycle back into the system, or to dispose off as irrigation water etc

From our point of view the important criteria are odour, and removal of suspended oil etc.

i do use the OIl trap but i did not reach to the removal limit,now i am thinking the DAF will work wel for rthis situation to handel.

Look forward to hearing your opinions on the above,

Thanks in advance.

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Dan Keys Senior Member Offline Dissolved Air Flotation Specialist Posts: 318 Florida, USA Gender: Company or Organization: KeysTec Environmental, Inc.	Re: DAF oil and grease removal % Reply #9 - Jan 16^th, 2011, 1:14pm Sir, You are correct that DAF is the solution to your problem. Please take a moment and re-post your question as a separate post rather than adding it to this post and we will address it in full.
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EECSA YaBB Newbies Offline I love Water and Wastewater.com Posts: 15 Company or Organization: gulfsaf group	Re: DAF oil and grease removal % Reply #10 - Jan 16^th, 2011, 1:23pm Thank u Dan, i'm gonna repost it as seperate topic.
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Gustavo Duarte

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Re: DAF oil and grease removal %
Reply #11 - Jan 3^rd, 2012, 1:12pm

Hey guys,

Does anyone have any calculation to preview the O&G removal in a DAF? I'm making a simple Excel DAF simulator and I can't find any information concerning it. For solids removal, I found a graph that helped me a lot.

I could input an O&G removal percentage and inlet O&G and output an O&G in DAF effluent, but I think it would not be the best way since, as commented above, O&G removal can be high if inlet concentration is high and lower if inlet concentration is low.

Thank you and best regards!

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Regards,
Gustavo Duarte

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Jeff Naumann God Member Offline I love Water and Wastewater.com Posts: 1133 Torrance, California Gender: Company or Organization: Jeff Naumann & Associates	Re: DAF oil and grease removal % Reply #12 - Jan 3^rd, 2012, 2:30pm Hi Gustavo: I'm not sure I understand what you are trying to accomplish. What do you mean by "preview?" Are you just trying to calculate "effluent O&G" from a given "influent O&G?"
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Re: DAF oil and grease removal %
Reply #13 - Jan 4^th, 2012, 6:02am

Hi Jeff,

Exactly. It's only a "no big deal" simulator I'm delevoping in Excel using some book equations. Based on literature, I found a graph that given the ratio A/S (air released/SS in influent, both known), I get SS in the effluent. This way, I could foresee how my wastewater would leave the DAF unit.

What I'm looking for now is a tool that I could make the same calculation, but now concerning O&G.

I hope you guys understood my question.

Regards!

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Regards,
Gustavo Duarte

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Dan Keys

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Re: DAF oil and grease removal %
Reply #14 - Jan 4^th, 2012, 10:48am

Gustavo,

A properly designed DAF which is properly installed and operated can remove greater than 95% oil and grease. However, there are multiple variables involved that have little to do with the equipment itself.

First, O&G can be present in the water in various forms including "free" (unemulsified) oil that readily floats, "water-in-oil" emulsion small globules that may or may not float, "oil-in-water" emulsion that suspends the oil and so on. Each condition requires variations in the chemicals used and perhaps manipulation of the pH.

So there just isn't any kind of simple formula for this or even for your suspended solids, as they will also vary considerably and are completely dependent on factors such as pH, the nature of the solids and the chemicals used for coagulation and flocculation.

The graph you found for solids reduction can only be for one particular application and package of chemicals used. Any change in any of the factors behind the graph will create an entirely new problem without changing the DAF itself at all.

Bottom line, there is no way you can truely express the performance of a DAF with an EXCEL formula. Undecided

Dan Keys

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Gustavo Duarte

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Re: DAF oil and grease removal %
Reply #15 - Jan 4^th, 2012, 11:12am

Hi Dan

I understand and totally agree with your considerations.

The graph I mentioned is based on experience with a DAF unit in a refinery, exactly the industry I work for, that's why I used it in the simulator, even knowing that it won't express the reality of any kind of equipment. As you said, it depends on a lot of factors, including the chemicals used and the reality of the process.

I'll try to achieve data from other DAF units from other refineries, such as inlet and outlet O&G and try to make a curve or something like that. Of course, won't express the truth fully, but it could be the best way to get some results closer to the reality.

Regards!!

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Regards,
Gustavo Duarte

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Dan Keys

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Re: DAF oil and grease removal %
Reply #16 - Jan 4^th, 2012, 11:29am

In that case, find the numbers (influent/effluent O&G) as a percentage of reduction from the records of a DAF that most closely matches your theoretical situation. I've seen all kinds of reduction levels in the petrochemical industry, depending on the stream being treated, the chemicals used (or not used) and the operation of the DAF.

Wink

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Gustavo Duarte YaBB Newbies Offline I love Water and Wastewater.com Posts: 30 Rio de Janeiro Gender: Company or Organization: Petrobras	Re: DAF oil and grease removal % Reply #17 - Jan 4^th, 2012, 11:46am Ok Dan, thank you for the help!!
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Re: DAF oil and grease removal %
Reply #18 - Mar 16^th, 2012, 12:52am

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I have more information can share with you, such as pictures, videos and successful cases, ect. If you are interested in, please send your E-mail to oilsludgedewatering@hotmail.com，

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Shivaram K Full Member Offline WaterandWastewa ter.Com is the best! Posts: 169 bangalore Gender: Company or Organization: Cadbury Schweppes ltd	Re: DAF oil and grease removal % Reply #19 - Mar 23^rd, 2012, 12:43am DAF can remove aminum of 95 % O & G and TSS if well designed and good flocculation
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