Water Environment Federation (WEF) Discussion Forums / WEF Discussion Forums / Operation & Maintenance

RE: Poor Settling (but not filamentous)

nadiae — Fri, 09 May 2008 10:16:23 GMT

Dear Mr. Koch,

I send you a PM, anyways.

Before you said it would be good to put down the waste line and the return sludge. But now you mention somthing about putting the return line up. I didn't get that very clear.

Thank you

Poor Settling (but not filamentous)

nadiae — Wed, 07 May 2008 11:20:02 GMT

Hi, in the plant we have a poor settling in the clarifier. We are working with not many filamentous m.o. but the settling is very poor.

we have a constant RAS flow. Do you think that could be the problem? What parameters should I check?

Thank you

RE: Poor Settling (but not filamentous)

J.W.Koch — Fri, 09 May 2008 09:26:44 GMT

You need to increase your mlss this will help you achieve some degree of nitrification. With the mlss that low it is likely you over wasted and are now over aerating which would explain the high ammonia. So try building the mlss and increasing the return sludge rate. keep us posted

RE: Poor Settling (but not filamentous)

nadiae — Fri, 09 May 2008 09:05:05 GMT

It would be great if we can get some nitrification going. We can change the velocity of the first and second agitator.

What about the recicle line that you told me before?

RE: Poor Settling (but not filamentous)

J.W.Koch — Fri, 09 May 2008 08:23:32 GMT

Are you required to nitrify? Is the high ammonia in your effluent? Is there any speed control on the mixers?

RE: Blower leaking oil

TerryF — Thu, 08 May 2008 17:15:22 GMT

It is unusual to have oil in the rotor chamber because it is at a higher pressure than the oil filled gear housing.

I am not sure about the Aerzen blowers but most brands do not have a proper seal between the gear box and the blower chamber but rely on close tolerances and labyrinth arrangement.

My only suggstions are:

1) Check that you are using the correct grade of oil.

2) Check that the gearbox is vented to atmosphere so that any build up of pressure is vented out rather than in.

3) The oil levels are correct as in not overfilled.

4) It will probably mean a strip down but a check of tolerances on the shaft and seals might be worth it.

Regards

TerryF

Blower leaking oil

J.W.Koch — Thu, 08 May 2008 10:41:05 GMT

We have two model 35 positive displacement blowers that have been seeping oil from pressure relief valves for about a year and a half. Does any one out there have Aerzen blowers or have a similar experience with a different brand. We are getting no real answers from the manufacture.

RE: Poor Settling (but not filamentous)

nadiae — Thu, 08 May 2008 15:45:29 GMT

Another thing,

We are having high levels of Amonia and low of Nitrite and Nitrate at this moment.

We can put down the recicle line, in which way would taht help?

RE: Poor Settling (but not filamentous)

nadiae — Thu, 08 May 2008 15:37:08 GMT

Thanks for the answer.

The Mholman Index is the SVI index. When you put the sludge in a tube you see like smooth.

I am not really sure if it works at extended aireation. The F/M and sludge age goes with it, but not the LVR, which is aproximately around 1.0.

The lay out of the aireation tank is six surface aireator Actirotor and it works as a piston flow. The first 3 aireator give more oxignen than the other 3. The OD in the last 3 is about 3ppm.

Does it help?

ATI chlorine analyzer

Rob Baur — Thu, 08 May 2008 14:30:56 GMT

Has anyone else had a problem with bubbles being carried over to the sensor on the ATI Cl2 analyzer? Contact me off list at

baurr(at)cleanwaterservices.org

Thanks

RE: High H2S feeding lagoon?

FreshAWL — Thu, 08 May 2008 14:10:44 GMT

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High H2S feeding lagoon?

Dennis — Wed, 09 Apr 2008 18:19:31 GMT

We may have to take over a private lagoon. I was wondering if there were anything special to consider if the influent is always high in H2S? The reason for the high H2S levels (we believe) is due to an extremely long detention time in both the force mains from each home's grinder pump to the subdivisions pump station, and also in the force main that carries all that collected waste to our system some 1.9 miles away! Another problem is that there are only 17 homes on the system, so LOW flow.... The TSS' and BOD's are typically in the 300mg/L range, so no problem there, pH's are 7.5 ish...

The lagoons came in to play when the subdivision couldn't comply with our pre- arranged agreement, and took it upon themselves to build and operate a lagoon! Now that the Department of Natural Resources has gotten involved, we may end up taking it all over.

We have an activated sludge plant and no lagoon experience, so just looking for things we should consider, while exploring all options.

Thanks,

RE: Poor Settling (but not filamentous)

J.W.Koch — Thu, 08 May 2008 13:33:33 GMT

Your F/M is in the range of extended aeration and I guess it safe to say that this is an extended aeration plant you are operating? Your MLSS # is very low specially for extended air typically anyways. Sounds like you may be over wasting and over aerating. Decrease your wasting and let your MLSS build up. You may want to try and reducing the return sludge rate if this is possible. This depends on how much you are returning compared to your influent "raw sewage" flow. If your plant is extended air I would try not wasting for awhile.

When observing the settability test how does the MLSS look in the cylinder is it smooth or granny in appearance? And what does Moholman mean ?

RE: Poor Settling (but not filamentous)

nadiae — Thu, 08 May 2008 13:03:35 GMT

Ok, I have done a few numbers... The sludge age is set to 30 days (taking into account the TSS of aireation tank and sedimentation tank), and it's done by wasting an amout of effluent, but the recicle is set at a constant rate (could this be one thing???).

I get an F/M of about 0.02/0.03, HRT is 35 hours (only the aireation tank), the MLSS is at about 1600mg/l (which I think is low) and in the recicle line in about 3000mg/l and with that we are getting an Moholman Index of more than 400.

We don't have a filamentous problem... What can you say about it?

Thank you

RE: Poor Settling (but not filamentous)

J.W.Koch — Thu, 08 May 2008 11:04:50 GMT

There are lots of things you can check. mixed liquor suspended solids in your aeration basin, pH, Dissolved oxygen and you could be over or under wasting. Look at these and let us know.

RE: How to get rid of Brown Foam

Sabir — Thu, 08 May 2008 00:39:03 GMT

Try this link and recomended cure;

http://www.alken-murray.com/NocardiaFrameSet.html

How to get rid of Brown Foam

Joey Campo — Tue, 06 May 2008 14:31:06 GMT

Hi, Has there been any more research on how to get rid of NOCARDIA BACTERIA. It has taken over my plant for about two years i have tried every thing known to man to get rid of it. You name I've done it. Had a lot of ww guys to check out my plant seems there is no answer to solve this problem. Just wanted to see if there is anything that I'm over looking. The plant is very small a 10,000 gal a day. Any help on this matter will be greatly appreciated. Cell 985-517-2930. jp.campo@charter.net

Thanks for your time

RE: Poor Settling (but not filamentous)

Victor — Wed, 07 May 2008 12:55:59 GMT

Nadia:

You say you have settling problems but do not describe the type of plant, domestic/industrial, flow, nutrient removal, whether you have bulking issues. You can still get bulking problems without filaments such as viscous/zoogleal bulking. Need more information about your plant before any help can be given as well as a microscopic examination of your mixed liquor.

RE: How to get rid of Brown Foam

TerryF — Wed, 07 May 2008 06:35:11 GMT

Joey,

There are lots of reasons , causes and solutions for Norcardia foamining and i would be certain that you have tried them all. One thing i did once with a pilot plant that got overrun with norcardia foam was to reduce the aeration rate. I still had the same DO , the same air volume etc but i just slowed down the rate at which it was applied and applied it longer(this was on a SBR which was not continuously aerated). Obviously this changes the biological dynamics but it also simply slowed the rate at which foam was formed.

Another time i used a small amount of polymer that was used on the main plant belt press , and sprinkled it on the foam.

Neither of these are solutions but did provide symptomatic relief.

Fixing the norcardia problem is normally related to DO , SRT , plant configuration etc.

Regards

TerryF

RE: Pilot for gas flare

Jerry — Tue, 06 May 2008 19:13:41 GMT

John/Victor

The person who spent a winter in a cabin with me would become a very religeous person. He/she would be using a lot of Rev Wright language at the end of the term.

Anyway that job doesn't start until August. I'm working on something in Missouri right now.

Pilot for gas flare

brich — Tue, 29 Jan 2008 16:09:03 GMT

I currenlty am running a Groth model 8391B Waste Gas Burner Automatic Ignition & Pilot Control system on my Anaerobic digester system with flows anywhere from 0 to 200 cfm depending upon the feed rate.

My question is what is the industry using instead of the propane pilot? There has to be a cheaper and better option to keep my flame lit?

This is my first post but I have been watching and learing from this board. There are some very intelligent individuals on here.

Thanks in advance for you help.

Ben

RE: Pilot for gas flare

g. — Tue, 06 May 2008 11:21:25 GMT

Sorry to rain on the parade, the alternative to propane would be Natural gas for pilot. Biogas may not be able to ignite or sustain a flame without a good quality gas source with it. An electrical heating element just isn't going to cut it under all operating conditions. From an environmental standpoint, unburned methane in the biogas has a 23 fold larger carbon footprint than the carbon dioxide by product.

RE: Pilot for gas flare

John Sansalone — Mon, 05 May 2008 13:18:43 GMT

Jerry -

So when are you likely to go there ? One of my coworkers recently spent a couple of months there (their summer / our winter), with the National Guard. I believe they said the temp. was a balmy 20 deg. or so.

So - would you be there just in time for winter ? (There's a thought - 5 months in a hut, in the dark, with Jerry. Can anyone say " cabin fever" ?).

RE: Pilot for gas flare

Jerry — Fri, 02 May 2008 20:04:45 GMT

"Dammit Jim"! I'm an operator, not a miracle worker.

RE: Water Distribution Operation Contract

TerryF — Fri, 02 May 2008 19:27:08 GMT

Manuel,

The single most important part of becoming a consultant is understanding yourself and getting your clients to understand what it is that you will do for them. You can be the best at what you do but if you can't get the relationship between you and your clientele right then your going no where.

Seems to me that you may have a bit of research and learning ahead of you. You probably need to get some proffessional advice from attorneys , accountants and business management advisers.

Regards

TerryF

Water Distribution Operation Contract

El Centro — Fri, 02 May 2008 02:33:03 GMT

Hello to everyone!

Understanding this is a Wastewater forum, let me please refer to a Water Distribution matter, I am in the process of becoming a Water Distribution Operation Consultant, but I don't have the slightest idea of how a proper contract should be presented in order to clarify all the expectations from my services, the implications and the liabilities.

By any chance, does anybody is already in such business that could iluminate a little bit my path. Your help is greatly appreciated.

RE: Pilot for gas flare

Victor — Fri, 02 May 2008 16:58:15 GMT

Dang it! That is all we need, Jerry melting the South Pole! By the way, you will still have to work for a private (contract) company down under--no different situation than what you were in the Isles.

RE: self heating anaerobic digester

mjwboofer — Fri, 02 May 2008 16:56:55 GMT

I liked the "thermal mass" idea but since you've got only 1' above ground, I don't think you're storing much of the sun's energy in the walls (concrete cover, perhaps???).

Is your feeding consistent throughout the day or do you feed once or twice a day? A daily morning (or midday) feeding schedule could explain a few of these phenomenon. You mention your gas production picks up in the morning when it is cooler. A new batch of cold, fresh sludge could explain both observations. The bugs likely spike in activity, producing heat throughout the day...and perhaps into the night. Since now that cooler sludge is heated by the mixers and the slightly exothermic digestion, your temp sensor picks up the added heat. But, by the time the tank is heated the bugs have gotten to the easily-digested sludge and the gas production drops off. The bugs and mixers maintain the heat through the night until the new batch of cold sludge comes in the next day. Sound possible?

I'm making some assumptions and probably oversimplifying this guess...comments? Criticism?

self heating anaerobic digester

brich — Thu, 10 Apr 2008 15:21:08 GMT

I have noticed a phenomenon happening in our anaerobic digester. We are in Texas and it appears that my 200,000 gallon digester self heats at night with a rise in temperature of about .5 to 1 degree F.

Anyone know what might cause this?

RE: Pilot for gas flare

mjwboofer — Fri, 02 May 2008 16:41:21 GMT

Some of the newer flares have the option of using the digester gas as the pilot source and an electronic ignition (so you're not wasting your potentially valuable gas to run a pilot). I agree that the propane or natural gas pilot option was never a stellar idea since there's plenty of digester gas available...no sense in paying for and piping up something else...but I guess the thinking was that an external source would provide a consistent pilot because if it goes out, you're not flaring but rather venting.

I'd check with the manufacturer to see if they have any recommendations...perhaps a retrofit Digester Gas, electronic ignition pilot? As was suggested, hopefully the energy is being utilized for boilers at least...cogen is preferable these days. Energy is getting expensive enough to justify the added scrubbing, equipment, maintenance, etc. in most cases.

RE: Pilot for gas flare

Jerry — Fri, 02 May 2008 16:15:48 GMT

Sometimes Paradise can be Hades. Remember what Milton wrote. Looking at a job in the South Pole (not kidding). Anyway, I'm looking for work. "Have settleameter, will travel".

RE: Pilot for gas flare

Jeff Naumann — Thu, 01 May 2008 20:05:13 GMT

KABLOOM! Cough, cough,hak,hak.

Jerry .........

Are you choking on my math? Maybe I made a great arithmetic error. One of those embarassing ones, where I'm out by a factor of a thousand.

How's it feel to be out of the flip-flop belt?

RE: Pilot for gas flare

Jerry — Thu, 01 May 2008 17:18:08 GMT

KABLOOM! Cough, cough,hak,hak.

RE: Pilot for gas flare

Jeff Naumann — Thu, 01 May 2008 15:58:41 GMT

What do you use the gas for?

My rough calculations, assuming that the average gas production rate is 100 cfm, 600 btu/cf for the gas, and a natural gas cost of from $1.00 to $1.30 per therm (100,000 btu), shows that you have about $1000/day in heat value. I hope that gas is not all being just flared.

100 ft3/minute x 1440 min./day x 600 btu/ft3 = 86,400,000 btu/day

At a typical natural gas heat content of 1000 btu/ft3, this is the equivalent of:

86,400,000 btu/1000 btu = 86,400 ft3 equivalent per day

One therm = 100,000 btu; 1 therm is approximately 100 ft3 of gas. The typical natural gas cost per therm in Southern California is in the range of $0.90 to $1.30 for industrial customers. Your local cost will probably differ. Propane is probably more expensive.

86,400 ft3/day = 864 therms/day; 864 therms/day x say $1.10/therm = $950/day

RE: Pilot for gas flare

brich — Wed, 30 Apr 2008 13:18:24 GMT

That is what I would like to do but I do not get a high enough gas pressure. Our gas is only at a 3 Inches of water column.

I am going to try it after I get a flame arrestor ordered.

RE: Lift Station Pumps

J.W.Koch — Wed, 30 Apr 2008 07:32:01 GMT

I would check into using grinder pumps do to the nature of the waste water. I believe that Flygt and Goulds brands both carry a grinder model.

Lift Station Pumps

Sewer Rat — Fri, 18 Apr 2008 10:15:47 GMT

We are in the process of redoing one of our lift stations due to a large truck stop coming in. I was looking for some info from people who have truck stops as to what pump you are using or what type we should look toward using. The stop will gravity feed to the lift station and use force main to plant. Any help would be appreciated.

RE: Pilot for gas flare

Bill H — Tue, 29 Apr 2008 17:42:35 GMT

Where I used to work it was set up to ignite the gas by a spark plug. We used no pilot flame. Why couldn't you just hook up the line to the gas line from the digesters?

RE: Pilot for gas flare

brich — Tue, 29 Apr 2008 16:11:03 GMT

ttt

RE: self heating anaerobic digester

brich — Tue, 29 Apr 2008 16:07:05 GMT

Nothing is manually or automatically changed at night.

Something in the microbes are causing the heating at night and I am not sure what it is.