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Uditha

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How to reduce the color of sewage plant discharge?
Feb 03^rd, 2012, 2:37pm

Hi All,

This is a sewage treatment plant with a SBR ( 2 hour aeration, 1 hour settling, 1 hour discharge). COD of final discharge is 240 mg/l where TSS of activated sludge is between 1000 - 1300 mg/l. 30min settling is 80 ml/l. The input to the SBR is only the liquid part of sewage.

The color of final discharge of the SBR is somewhat brownish. What can I do to reduce the color and make it much clearer..? ( I am expecting a solution other than chlorination)

Thank you and best regards,
Uditha

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The sludge judge God Member Offline Posts: 649 Wisconsin Gender: Company or Organization: private	Re: How to reduce the color of sewage plant discharge? Reply #1 - Feb 3^rd, 2012, 2:47pm In the lab take a sample of your effluent and run it through a filter. If the color goes away you know you turbidity (TSS) is the problem. Try this first and let us know so the correct course of action can be advised. regards, Ryan
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Uditha YaBB Newbies Offline I love Water and Wastewater.com Posts: 3 Colombo Gender: Company or Organization: Waterman	Re: How to reduce the color of sewage plant discharge? Reply #2 - Feb 3^rd, 2012, 11:47pm Dear Ryan, I filtered the final discharge. But the problem remains same. Still the color is brownish. Regards, Uditha
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The sludge judge God Member Offline Posts: 649 Wisconsin Gender: Company or Organization: private	Re: How to reduce the color of sewage plant discharge? Reply #3 - Feb 5^th, 2012, 2:12pm Likely some form of advanced oxidation is needed. I'd be lying if I told you I knew much about color removal. Dr. Henry is the forum expert in this area. I suggest you try to contact him about your problem and some possible solutions. best regards, Ryan
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DrHenry God Member Offline Ride, boldly ride, The shade replied... Posts: 788 Raleigh, NC Company or Organization: CESTAB (see bio)	Re: How to reduce the color of sewage plant discharge? Reply #4 - Feb 6^th, 2012, 4:59pm You say this is sewage. Is it 100% sanitary or is there some industrial component? What is the influent color? When does the brown develop? Can you take some color measurements so we have some numbers?
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DAVIDCMOORE

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Re: How to reduce the color of sewage plant discharge?
Reply #5 - Feb 6^th, 2012, 7:30pm

IM NO EXPERT BUT IF YOU WOULD LIKE TO KNOW WHAT I THINK HERE GOES FIRST OF ALL THE EFLUENT OF SBR IS PRONE TO SHORT CIRCUTING DENSITY CURENTS CLARIFICATION IS NOT IDEAL I WOULD TRY AERATING A BIT MORE IN HOPES OF ACHIVING BETTER OXIDATION AND PROMOTE BETTER SETTLING.....THANKS LIKE I SAID IM NO EXPERT....

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sobisch God Member Offline Posts: 1777 Gender: Company or Organization: L.U.M. GmbH	Re: How to reduce the color of sewage plant discharge? Reply #6 - Feb 7^th, 2012, 2:19am Dear Uditha, what is the source of the wastewater. Brown colour due to polyphenols, lignins or humic acids is difficult to treat. Combination of anaerobic/aerobic treatment and coagulation with ferric was used in some cases to improve colour removal. Kind regards T. Sobisch
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grrun

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Re: How to reduce the color of sewage plant discharge?
Reply #7 - Feb 8^th, 2012, 12:24am

Because the SBR has 6 cycles/day, have you noticed any difference in the color of the discharge with the time of day? While you have identified the cycle time for the SBR; does it run at full capacity each cycle? My guess would be that the color might be less in the time from 10 PM to 6 AM. If so, this may require some operational changes.

240 mg/L COD seems rather high for a fully treated discharge and the color seems to be soluble. Have you tried chlorinating in jar tests? I was curious why you were looking for a solution that didn't include chlorination. However, if chlorination eliminates the color, then a longer aeration cycle might accomplish the same effect and bring down the COD concentration.

If the color is not associated with the 240 mg/L of COD, then Sobisch and DrHenry may have some suggestions for chemical additions for color removal. DO and pH would also be useful information.

grrun

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DrHenry

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Re: How to reduce the color of sewage plant discharge?
Reply #8 - Feb 8^th, 2012, 12:38pm

Grunn, I don't know if it is the case here, but some regulatory bodies have just said absolutely no chlorine. We have stopped using it except for disinfection on the front end and switched to ozone for a reative oxidation. This is not that chlorine doesn't work well, it is just not worth the headache when putting in a new system knowing that six months from now it may not be allowed based on the negative PR of chlorine.

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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: How to reduce the color of sewage plant discharge? Reply #9 - Feb 8^th, 2012, 2:07pm Wait until the paranoid folks start coming down with typhoid. Then, chlorine might seem like a good idea.
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Mike F YaBB Newbies Offline I love Water and Wastewater.com Posts: 1 Company or Organization: Cumberland Co. Utilities Auth.	Re: How to reduce the color of sewage plant discharge? Reply #10 - Feb 17^th, 2012, 12:02pm We had a similar color problem when accepting a wastewater with high TDS. Difficult to treat.
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aquaticonsult

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Re: How to reduce the color of sewage plant discharge?
Reply #11 - Feb 17^th, 2012, 6:49pm

Well, we are all shooting in the dark without more info. What level was the filtration that still shouwed color? UF (0.02micron) will take tannins out of the water; I've had good luck with DE also taking a lot of color from very small precipitate and increased where polarization of the effluent is done prior to DE - so that you get getter floc accumulation on the DE particles. DE goes to 0.5 micron.
Alum or Cerium or Lanthanum coagulation could also be used by injection prior to settling basin/tank -
Just some ideas to try bench/jar testing on.

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C. Gillen God Member Offline Applied Environmental Biotechnology Posts: 773 Ireland Gender: Company or Organization: BioFuture Ltd.	Re: How to reduce the color of sewage plant discharge? Reply #12 - Feb 20^th, 2012, 11:59am Hi Uditha, I would agree with grrun that the relatively high final effluent COD would worry me. Another area to look at is the MLSS which seems quite low. More MLSS would tend to adsorb more of the colour to the flocs and ultimately lead to degradation. Best regards, Cgillen
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ronekyng YaBB Newbies Offline I love Water and Wastewater.com Posts: 6 Gender: Company or Organization: Fande tech.	Re: How to reduce the color of sewage plant discharge? Reply #13 - Feb 21^st, 2012, 3:49am Hi Uditha I think maybe an anoxic process may work.Things may be yellow or brow when it is oxidized
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BillCardinal

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Re: How to reduce the color of sewage plant discharge?
Reply #14 - Mar 7^th, 2012, 2:42pm

Color in my process is a problem as well. We have a very simple pond system which flows into a final settling lagoon. The algae begins there causing very highly colored green water. From there we have to chlorinate it to meet the required <23 mpn not to exceed 230 mpn. The disinfected water (sodium Hypochlorite 20 ppm) flows into a very large storage pond and then creates HAA's. The color problem persists as the final pond water is the source for a Reclaim Plant. The UVT is barely high enough to keep disinfection with UV at times of the year. We are about to do a little work with Ferric Sulfate and Sulfuric acid repressing the pH to <5. This removed the color on the bench to an exceptable range.

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dmoore25 YaBB Newbies Offline I love Water and Wastewater.com Posts: 3 Company or Organization: Waste Water Queensland	Re: How to reduce the color of sewage plant discharge? Reply #15 - Mar 19^th, 2012, 2:20am Good day! Just wanna say thank you so much for sharing this article about how to reduce the color of sewage plant discharge. I appreciated it a lot! Best wishes, url=http://www.wastewaterqld.com.au] wastewater management [/url]
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annracimo YaBB Newbies Offline I love Water and Wastewater.com Posts: 9 Company or Organization: student/researcher	Re: How to reduce the color of sewage plant discharge? Reply #16 - Mar 20^th, 2012, 7:47pm hi! is it the same for a landfill leachate treatment plant using ifas? the effluent in the clarifier is still brown to light yellow but it's already odorless. i was wondering what went wrong with it.
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sobisch God Member Offline Posts: 1777 Gender: Company or Organization: L.U.M. GmbH	Re: How to reduce the color of sewage plant discharge? Reply #17 - Mar 21^st, 2012, 1:57am likely humic acid like materials remain in the treated effluent.
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annracimo YaBB Newbies Offline I love Water and Wastewater.com Posts: 9 Company or Organization: student/researcher	Re: How to reduce the color of sewage plant discharge? Reply #18 - Mar 21^st, 2012, 2:47am ouch. humic acids? you said it's hard to treat. how can we treat it? if we filter the effluent sample and the color lightens/clears, then it's just TSS right?
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BillCardinal YaBB Newbies Offline This is what I do! Posts: 3 Copperopolis Gender: Company or Organization: Calaveras County Water Distric	Re: How to reduce the color of sewage plant discharge? Reply #19 - Mar 21^st, 2012, 8:37am What about tring Ferric Sulfate with Sulfuric acid with depressed pH to <5.0. I am running this test right now with results to follow.
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