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Greywater treatment and re-use

Aaronbn1 — Wed, 13 Feb 2008 20:37:22 GMT

I am researching a system that will take the greywater from my washer, kitchen sink, and showers and allow that water to be re-used as toilet flushing water. I saw an article in Mother Earth News about this. The system that someone had tried there had a collection tank that they strained, added bleach, and then pressurized and plumbed it back into special lines that went to the toilets only. This made the load on the septic much lighter. Has anyone done any work in this area or know of anything like this? I am very interested.

RE: Greywater treatment and re-use

Jeff Naumann — Wed, 13 Feb 2008 20:57:06 GMT

To a great extent, what you can do depends on how much property you have to work with, and how complicated you want to get. I have an average home, with large backyard. Since my washer is essentially outdoors, and I live in an area where freezing temperatures are not likely, I just water the backyard with the washer water. You have to be careful about using bleach (I never do), or really hot water, which might harm plants or the lawn. I suppose that you could use kitchen water for watering plants if they are near the kitchen drain. Again, it would depend on whether you have freezing conditions. I think that capturing water from the shower or bathtub would by more difficult, but that would depend on your particular situation. I wouldn't worry about needing to filter or chlorinate the water if it's going to be used for landscape watering.

If you have a basement that makes the drainage system easily accessible, I suppose you could capture the "non-toilet" waters in some kind of tank, and then supply the toilets with a separate system, which would require a separate pump. Sounds like it would be more trouble than it's worth. Easier just to use "low-flow" toilets. One famous phrase from the past during drought times in California is "if it's yellow, it's mellow; if it's brown, flush it down."

RE: Michigan Industrial Wastewater exam for constructed wetlands

steve — Fri, 01 Feb 2008 15:59:28 GMT

No but I have to deal with the D E Q on a regular basis. I did find that there is a company which provides pure artesian water to Southeastern Michigan. NO bottles. they bring it to your home or business by a tanker truck. They pipe it to your Refrigerator, cooler or coffee maker. Check it out. www.millbrookwaterco.com , Steve

Michigan Industrial Wastewater exam for constructed wetlands

rwhitworth52 — Wed, 25 Oct 2006 15:59:38 GMT

Has anyone taken the Michigan Industrial wastewater exam for constructed wetland ?

What is the format ? multiply quess, essay, or true false

Thanks

RE: Looking for ideas on thickening sludge in sludge holding tanks

Grant H — Fri, 01 Feb 2008 07:52:49 GMT

I used to help run package extended aeration plants like this. The mixed liquor was wasted into these types of tanks and let settle. Then we had a hose fitted inside the tank that we could lower and then we would open a valve and slowly decant the supernatant back to the wet well. This gets the MLSS from 3000 mg/L to 10000 mg/L = 1%. This maximum can be worked out from your 3-24 hr settling test (eg. 3000 ppm X 1000ml/250 ml settling = 12000 mg/L = 1.2%).

Our operators had another trick where they would add Sodium or Calcium nitrate (dissolve the powder in water in a bucket and add to the tank during decant). The addition of the nitrate to freshly decanted sludge will cause denitrification and nitrogen bubbles will float the sludge particles to the top of the tank. You then decant the supernatant from the bottom of the tank. The sludge should be better than the gravity option, if you allow some time for the solids to float and water to drain (just like the slow rake time for the float sludge in a DAF tank). I would start with a dose of say 50 mg/L = say 1 lb powder per 2500 US gal tank. You may need to decrease or increase the quantity. Monitor you supernatant for solids and if too high add more nitrate. If the solids of the float is not too good add more nitrate. I am sure you will find it a winner. However you probably also need to check that there is not too much nitrate in the supernatant - particularly if you have limited efluent discharge limits.

Alternatively you would be looking at polyelectrolyte. A 2500 gal tank contains 27 kg solids at 3000 ppm MLSS. Dosing poly at around 3 to 5 kg/tonne requires 80 to 135 g of poly. Select an anionic liquid emulsion polymer (get you rep to help you) and you would use 150 to 270 ml/2500 gal. However you need a polyblend unit of appropriate size and then secondary dilution to get the polymer thin enough to dose into the pipe from the aeration tank to the sludge tank. Sounds a lot of cost and worrying about the equipment.

Looking for ideas on thickening sludge in sludge holding tanks

WaterPlanet — Fri, 25 Jan 2008 15:25:20 GMT

My company operates several small, on-site wastewater treatment plants. By "small" I mean 5,000-25,000 gpd.

Sludge is wasted to sludge holding tanks. The tanks are buried septic tanks. The sludge is pumped periodically by septic haulers and taken to large municipal wastewater treatment plants. The frequency of the pumping ranges from as often as once per week to as infrequently as once per month. The waste sludge is typically around 1-2 percent solids, but sometimes, as in the case of a plant that we just started running, the sludge is more like 0.5 percent solids.

Question: Has anyone had a good experience using polymers, metal salts, or other agents to easily and economically thicken the sludge to closer to 2 percent? If so, how was the product mixed with the sludge? I'm thinking that the ideal solution for us is to add a cup or so of some product each time a few thousand gallons of RAS is wasted, and to mix it with a submerged pump. But I don't know what product to try. Absent feedback, I'll start ringing up vendors.

Would very much appreciate learning from others' experiences. Thanks..

RE: Looking for ideas on thickening sludge in sludge holding tanks

TerryF — Fri, 25 Jan 2008 23:54:08 GMT

I would suggest getting a couple of gallons of WAS from the plant and doing some jar tests. I don't think any one will be able to give you any better guidance as these things tend to be plant and application specific.

I would start off with what ever you have or can get hold of easily. 2 percent solids might be possible but it would be certainly easier to achieve if you had a special thickener rather than just a septic tank.

Regards

TerryF

RE: Red Lagoon in Iraq

Joel B — Fri, 25 Jan 2008 16:03:07 GMT

it very likely is red due to purple sulfur bacteria, which thrive in anoxic conditions. So the red lagoon may be that color due to heavier BOD loading.

Red Lagoon in Iraq

kevinjctx — Thu, 18 May 2006 09:26:09 GMT

I am in Iraq and have three lagoons to operate. My background is contact stabilization so I"m new to this. For now they are containment only. No discharge. The Euphrates Rives is only 3 miles away but in hostile territory. Lagoon Alpha flow into Bravo and then into Charlie. Total capacity is around 31 million gallons. Black and grey water trucks are dumped into Alpha which is full and Bravo has about 2 ft with Charile still empty. My problem is that Bravo has turn very red and Alpha a bright green. I've researched it and think it might be algae but there are no blooms. Why Bravo and not Alpha?

Kevin Cochran

KBR Services Inc.

RE: Lagoon denitrification

Joel B — Fri, 25 Jan 2008 15:35:02 GMT

Cain,
I would consider running all influent to 1st aerated cell, putting a skimmer outlet on first cell to retain solids to build up nitrifiers, having extra aerators in first cell and then alternating them so that when an aerator turns on it kicks up solids that had settled in that area previously. The goal would be to get the TSS up in the first aerated cell to as high as you can, to increase nitrifier population. In most lagoons TSS comes in at 200mg/l and due to settling is 50 mg/l at the outlet. If you can keep it at 300-1000 mg/l in first total mix lagoon, you should nitrify just fine. Most likely, if you adjust aerators to keep DO just above 0 you will de-nitrify in the same lagoon, no need for the anaerobic lagoons with their odor issues. The downstream aerated lagoons will most likely not contribute to nitrogen removal at all due to no significant TSS in them. We can discuss this in more detail if desired, we have some experience with success with this approach.

Lagoon denitrification

Cain — Sun, 06 Jan 2008 19:48:54 GMT

Hi. Was wondering whether anyone had any experience or advice on achieving reasonable Nitrogen removal in lagoons?

We are looking at options to upgrade an existing lagoon. Our current thinking is to separate the lagoon into six cells in series. The cells would be an aerated cell with 2 days HRT, anoxic with 0.75 HRT, 2nd aeration with 2 days, 2nd anox with 0.75 days followed by a 3rd 1 day aeration cell and a large final cell for settling prior to discharge. We would split influent 50% to the first aeration cell, 25% to first anox and 25% to second anox.

The detention times are based on the full flow i.e. as only 50% flow goes to cell 1 the actual HRT for cell 1 would be 4 days. Aeration would be set point controlled using fine bubble diffusers.

We would also look at adding attached growth media to aeration cells to enhance year round nitrification. We are only looking for an effluent TN of < 15mg/L and there doesn't appear to be any limiting parameter in the influent. Influent flow is pretty stable. Any advice, experience or ideas very much appreciated.

Thanks

WW treatment in S America Rainforest

Emery L — Wed, 23 Jan 2008 19:47:45 GMT

WEF Form Members,

I have recently through my local WEF affiliation's become a Professional Mentor for some students at ASU (local university) in their Engineers Without Borders program. They have a very interesting project in a rural community of Ecuador. The community has a broken water system and little wastewater infrastructure. Current cesspools and septic tanks are daylighting and adding to the health problems of drinking water not disinfected. A traditional septic seems to be out of the question due to local groundwater at 2 to 4 feet bgs. As you can guess the community members have serious health problems associated with sewage contamination of community surface waters.

More info on their website:

http://ewb.asu.edu/tsuraku/index.htm

I am helping them with the design of a community master plan and sewage treatment facility (supporting about an 800 person build-out). They have settled on the idea of a lagoon treatment system with a cartage system until the town can raise enough capital for a sewer system. This seems to be the lowest capital and O&M cost. The village consists of about 40 homes, a school, medical facility and church. Previous efforts to provide community bathrooms (clustered system) have not been successful. The citizens want flushing toilets in each home.

A big push of our efforts is public health related. Without adding too much more info I was curious if anyone had experience in this type of project? I have done this type of work in the US but this is a totally different animal. Is there anyone with success (or horror) stories of a system that we may be overlooking for a project with a VERY limited budget?

Thanks in advance.

Take care,

Emery

RE: WW treatment in S America Rainforest

Emery L — Wed, 23 Jan 2008 21:15:01 GMT

Jeff,

Thanks for the info. I understand your O&M concerns. It is my understanding that the EWB program at ASU has committed to a 5 year program to follow up with them. They currently have an operator for the water system and the townsfolk is charged $1 per month. The plan is to train another operator for the sanitary system and cross train them both on the w & ww systems. The town is also a community center for a local tribe...hence the additional "wanting" for those things of the modern world. They recently got an small building with internet access.

Looks like a good idea to leave on the list for the March trip where some team members are going to propose several ideas and come up with the ultimate solution.

Thanks again.

RE: WW treatment in S America Rainforest

Jeff Naumann — Wed, 23 Jan 2008 20:12:49 GMT

For some time now I have following an interesting blog of an American who has become an expatriate living in fairly rural Mexico. He has installed a composting toilet at his home there. Here's a non-working direct link that that blog, specifically talking about his composting toilet:

http://www.vivaveracruz.com/blog/?p=421

Frankly, for a rural system in Equador, with only a small number of hookups (or, not even hookups), and shallow groundwater, I think something like Sr. Calypso is doing in Mexico makes much more sense. Often, people in the non-first world want what those in the first world have, with no practical understanding of how to operate it, or the will to properly maintain it. Who is going to pay for and operate/maintain even a simple lagoon system in a rural area.

RE: Lagoon denitrification

Wiff P — Fri, 11 Jan 2008 12:46:18 GMT

I'm not sure how cold it is where you are but could take a while to get going if you're only starting now in January so be patient. Also agree with recirc idea although could present a practical challenge in cold weather but if you can recirc even at 100% feed forward from last aerobic cell before settling that would likely be helpful in getting denitrification going. You don't mention influent condentrations or loadings but assume all this is with conventional municipal wastewater. Would watch DO concentrations in the different lagoons (will require sampling in various locations to really get a good handle on overall DO environment in each lagoon) but you'll want to check this to see if you're actually creating the right environment in each lagoon for both nitrification and denitrification.

Wiff Peterson

RE: Lagoon denitrification

TerryF — Mon, 07 Jan 2008 15:59:38 GMT

Cain,

In broad terms what you are proposing looks okay without doing the numbers. At the end of the day your results will depend on how big of a population of nitrifiers you can build up and being to maintain adequate aeration.

If your last cell is being used for settling , you will need recirculation up to the first cell to bring back nitrifiers. You don't say how big your last cell is but you should be careful about algae growth etc in that cell.

I agree with Jerry in that a filter might be worthwhile afterwards. Even an aerated rock filter outlet might be better than nothing.

Regards

TerryF

RE: Lagoon denitrification

Jerry — Mon, 07 Jan 2008 11:49:27 GMT

I would follow the existing lagoon with a Recirculating Sand Filter.

RE: Lagoon denitrification

Victor — Sun, 06 Jan 2008 22:21:27 GMT

Cain:

It appears that a resource for lagoon management is what you are looking for. In my honest opinion, the best online resource for lagoon information is www.lagoonsonline.com There is also a dedicated online forum.

Disk Filter Rotation

01667602 — Mon, 17 Dec 2007 13:00:36 GMT

We had an Aqua-aerobics disk filter which has been running backwards (for a long time). One of the brackets holding the spray nozzle on broke. After talking with the factory we found out this unit has been running backwards, probably since installation. It should rotate down into the back wash headers. I have heard of more than one unit doing this and could not find any notes to check it. Has anyone else had this problem? I would recommend everyone check their unit since it does work in both directions. This broken bracket did some damage to our unit and could have torn the filter if we hadn't caught it immediately.

Let me know how many are going the right way and how many are not.

Thanks

RE: Algaecide usage in California

Jeff Naumann — Fri, 14 Dec 2007 13:31:39 GMT

One favorite used to be copper sulfate or copper hydroxide. It's still used in many pesticides, and probably as an algaecide. Another possibility is chlorine.

Algaecide usage in California

rwhitworth52 — Tue, 23 May 2006 17:31:01 GMT

Is there any algaecide that can be used in California ? Do you need an appliers certification ?

Thanks

RE: Algaecide usage in California

Jerry — Fri, 14 Dec 2007 12:16:02 GMT

Barley hay.

RE: Algaecide usage in California

Big Kiwi — Sat, 03 Nov 2007 08:23:14 GMT

I have read somewhere that the use of straw bales in ponds and lagoons has been used for reducing algal growth. Probably googlable for a full article on it. And I imagine as it is a 'natural' remedy that it will be acceptable for Calif. regulations.

Cheers

Simon T

RE: Orenco Fixed Film Treatment systems

bugwisperer — Wed, 31 Oct 2007 20:48:49 GMT

Many thanks Jerry - http://www.orenco.com/ots/ots_adv_commercial.asp

Orenco Fixed Film Treatment systems

bugwisperer — Sun, 28 Oct 2007 14:45:53 GMT

Does anyone have any experience with this system? Its a STEP collection system followed by sort of a recirculating sand filter system sans the sand filter - they use big plastic boxes with a 1/2" thick non-woven geotetile fabric which is draped over rods and hung packed close together in these plastic boxes - sort of a packed bed system. The septic tank effluent is sprayed over top of the packed material via spray nozzles- media stays unsubmerged and is dosed intermittently. Drainage goes back to recirculation tank. Iterested in any comments on permit parameters met (or not), reliability, ops cost, problems. Thanks!

RE: Orenco Fixed Film Treatment systems

Jerry — Mon, 29 Oct 2007 23:29:56 GMT

What does orenco call this system? Maybe they have a model number. Let me know and I will give you an opinion.

x

SRB — Wed, 24 Oct 2007 15:58:58 GMT

RE: How to lower ammonia level in an sbr plant

D Shulmister — Mon, 22 Oct 2007 13:13:10 GMT

Bob is correct -- the alkalinity numbers sound way off. My plant influents usually run around 100 to 140 mg/L alkalinity. You won't get conversion of ammonia if there is not enough alkalinity.

How to lower ammonia level in an sbr plant

LaurieH — Wed, 22 Aug 2007 12:19:27 GMT

HELP!!!!!!!

I am operating a small sbr plant, (.5 mgd), I am having problems with one of my basins being sky high in ammonia. Will raising my react time lower my ammonia? Need help quickly, EPA is looking over our shoulder. What would be the fastest way to get the ammonia lowered? I hope someone has a suggestive, I'm desperate!!!

Thanks,

Laurie

RE: Ammonia Removal in Wetlands

John Sansalone — Sun, 21 Oct 2007 15:39:02 GMT

Re-reading some of this post, now that it has come back up, I see one item that can be clarified. The limit for unionized ammonia is pretty low, but the proportion of ammonia in the ionized or unionized states depends upon the pH and temperature. You may find that the standard being applied to the effluent actually represents a total ammonia that, while tight, is very achievable. Around here, we have a number of STPs that successfully meet total ammonia limits in the 1.2 - 2.4 range. The 5.0 should be do-able. The 1.0 sounds a lot tougher, but not impossible. I'm still waiting to see it demonstrated that the reed bed systems will consistantly meet those type of limits in winter.

Ammonia Removal in Wetlands

Sewerpro — Thu, 23 Mar 2006 15:55:40 GMT

I'm trying to assist a Girl Scout Camp that currently has a recirculating sand filter. Their effluent ammonia is typically less than 5 mg/L. Influent flow is 13,000 - 20,000 gallons per day, but only 6 months out of the year.

Their new permit limits their ammonia discharge to <1 mg/L ammonia year round. Since the camp is remotely located and does not have an operator, we are considering adding a wetland to remove the last bits of ammona.

Does anyone out there have any data that would help us justify our process selection to the State? Does anyone operate a wetland that has an ammonia limit?

Thank you!

RE: How to lower ammonia level in an sbr plant

bugwisperer — Sun, 21 Oct 2007 15:11:57 GMT

TerryF (10/21/2007)

I must have been away the day we were taught the relationship between floc size and MLSS , but maybe things work differently at higher elevations.

Here in the deep south this is how things work. For a given plant and a given load if i increase my MLSS theoretically i can get by nitrification wise with a lower DO. The total air required may go up a little because of greater endogenous respiration but the plant will work with a lower DO. The relationship is not linear but is proportional to some extent. Suprisingly enough the design equations for nitrification also support this relationship.

Last time i looked this was one of the principles behind oxidation ditches: Big tanks , lots of biomass (low F:M) but generally lower DOs which produces stable nitrogen removal performance.

Now with my given plant and my given biomass if i suddenly have a big hit of ammonia i require more air to increase the oxidisation of the ammonia and as the nitrifiers have to work harder i may have to raise the set point to achieve adequate oxygen transfer. (See comments in one of my previous posts about an overloaded plant requireing 4mg/l).

Many plants that are under aerated for whatever reason may show some improvement in nitrification capacity if the MLSS is reduced because the endogenous demand is reduced enough to increase the DO in the MLSS enough to get some oxygen transfer happening. Alternatively the aeration rate could be increased which would achieve the same thing.

At least i think thats how it works!!!

TerryF

Well, I believe the F:M and mixing energy provided will in fact impact the size of the floc particle. You know - quantity and characteristic of EPS bug glue on cell exteriors? Case in point - everyone "knows CBOD reduction has to be down in the range of 20-30 ppm before nitrfication really kicks in"... right? whys that? why doesnt separate stage nitrfication work real well and why do the nitrifiers have a tendency to wash out in such process configurations? It is because nitrifiers are really heterotrophic wannabees and live to incorporate themselves into the heterotrophic floc particle or onto the fixed film depending on the process? Ok, so we know where the nitrfiers like to hang out. How come nitrfication doesnt kick in (full steam) the first minute when the first drop of wastewater enters the aeration basin? Could it be that the bulk fluid DO is scavenged by the heterotrophs occupying the surface of the floc particle such that the DO on the interior of the floc structure is so low that only a minute fraction of the autotrophic organisms have adequate DO for nitrification? This is exactly what happens. Until the oxygen demand is reduced to close to the endogenous (carbon largely gone) demand the autotrophs are not hitting on all 8 cylinders - ok, 6 cylinders with a turbocharger. In cases where we have a very heavy mixed liquor and need to achieve the maximum nitrfication rate because the engineer didnt get the client to pay for a treatment tank way bigger than it really needs to be, then we are going to need to run a DO over 4 ppm to achieve this maximum rate,ie, using all the autotrophic organisms in the process as efficiently as God allows them to be. Again, mixing plays into this too from the perspective of insuring even distribution of DO and nutrient throughout the bulk fluid. Think of it this way - you have a crowd of a million people standing shoulder to shoulder versus a million people standing at arms length to each other. If you had to walk thru the crowd which would be easier? (possible?). I have a hard time diffusing oxygen into the tight crowd - cant get it in all those nooks and cranies unless I create greater force in a higher DO to drive it in there - chem E stuff you know - higher temp to lower temp - higher concentration to lower concentration drives the rate of the reaction so to speak. To get thru the tightly packed crowd you would have to have one heck of a big guy (high DO) behind you pushing. And, I maintain, the same applies to DO, MLSS and the floc particle itself - the high DO pushes through the crowd of organisms in the bulk fluid and floc particle so when it finally reaches, Fred and Mary, nitrifiers of good repute, they have enough DO remaining such that they can do their thing at an optimal rate. Certain things in wastewater just arent taught in school - I believe I have a paper in work from some PHd type who somehow actually measured DO on the floc scale basis although that happened to be in very recent times. In an SBR one doesnt have a lot of time to mess around - dilute your influent ammonia by 1/3 (say the batch volume) to say what - 18-22 ppm?? so we have to spend a half hour doing our CBOD reduction from say 80 to 10 in consideration of mix and then have the rest of the time allocated to nitrfication. We should get a pretty good specific rate and have this done in what - 4 -5 hrs maybe.

There is no question nitrfication occurs at low DO; we run a small plant , domestic wastewater local to our office at about 0.45 ppm at MLSS = 3000. We completely nitrify and typically have a total N going out of less than 2 ppm; permit is 10ppm as it goes to the ground. Its an MLE plant, ie, no second anoxic. Did I mention there is about 2 days HRT? ie, nitrfication rate and denitrification rate are not optimal but there is boocoos of time in the process so no biggie - we get by with the slower rate and as a side bonus achieve a lower TN than we otherwise could with an MLE process. Same approach as the symbio gizmo sans the messing around, and oh, pay no attention to that capacity issue. Play games with DO and nitrify and denitrify simultaneously but for a given MLSS concentration the sweet spot DO (DO at which we are nitrifying and denitrifying at a rate high enough to achieve our permit goal within the time in the process) will be higher the higher the MLSS.

As we are aware, extended aeration and oxidation ditch (ie, extended air plants with a psuedo 200Q internal recycle pump) processes are as big as they are and were developed not because the treatment time is actually needed to achieve permit if the reaction rates are not purposely (or by accident) limited ; they are as big as they are: 1. to minimize sludge production, 2. civil engineers (and I is one) are going to have a harder time screwing things up and not achieving permit if they design this process. 3. You know- 1-800-Vendor. One can run ammonia on a normal domestic waste extended air plant about half way thru the process on supernatant from the 30 min settle test and read 0.1 ppm year round assuming DO and alkalinity are not limiting. Nitrification rate is nitrfication rate, ie, zero order, over the two-Ks value for ammonia, ie, run the ammonia up above 1 ppm, as high as you want - nitrification rate aint going any faster. Its first order relative to bugs, ie, the more you have, the faster you go at a given temp to the extent you have ammonia available in the process for them. You can raise the SRT as high as you want but it doesnt mean you are going to have more and more nitrfiers - that will be limited by the raw wastewater N and the contribution from heterotrophic decay. If a system is overloaded with regard to ammonia such as one that might have a contributory school (because the engineer didnt know the "ammonia" was not 45 ppm and TKN was really 130 ppm ish) then running a 4000 MLSS with a lower D.O. isnt going to cut the mustard. Its not because the ammonia concentration is higher, its because we arent effectively using all the nitrifying organisms we have in the process to nitrify at the maximum rate they are able to if they have an unimpeded source of DO. We had terrible trouble at a plant in FL which we ran MLSS at 5000 to 5500 in the high season when all the snowbirds came down for the winter. The problem was we did not have isolated blower piping so we had to try to balance the air with butterfly valves - by the click you know. Inevitably backing off one basin one click and opening another basin one click wouldnt take the DO from 5.8 ppm (excellent nitrficiation) to 5.0 ppm in one basin and from 3.8 ppm (poor to little nitrfication) to 4.8 in the other basin - it would be like 5.8 to 3.5 and 3.8 to 5.5 so we'd really almost stop nitrfiying in the first and start in the second and round and round we'd go. Certain things in wastewater just arent taught in school - I believe I have a paper in work from some PHd type who somehow actually measured DO on the floc scale basis although that happened to be in very recent times. I maintain that you will effectively shut down nitrfication at a DO above 2 ppm in a heavy mixed liquor because I have seen it happen and can make it happen.

So if one gets "hit" with a slug of ammonia its true that more lbs of air are needed to achieve this total oxidation. What is really happening though is that the rate of nitrfication needs to be increased by allowing all of the nitrfiers to hit on all 6 cylinders since we have a higher concentration to treat within the same HRT in the process. No, the "oxygen transfer" into the bulk fluid is not impeded by a higher ammonia concentration in the "slug". But to git-r-done within the HRT of the process we may need to jack up the DO so we are able to drive the DO throughout the MLSS to effectively maximise the rate of the nitrfication reaction. This is what I have observed in the field in FL, NC, VA, PA, DE, MD; IN;Il; other states could be different.

...and the bug knows best.

RE: How to lower ammonia level in an sbr plant

TerryF — Sun, 21 Oct 2007 04:07:37 GMT

I must have been away the day we were taught the relationship between floc size and MLSS , but maybe things work differently at higher elevations.

Last time i looked this was one of the principles behind oxidation ditches: Big tanks , lots of biomass (low F:M) but generally lower DOs which produces stable nitrogen removal performance.

At least i think thats how it works!!!

TerryF

RE: Ammonia Removal in Wetlands

bugwisperer — Sat, 20 Oct 2007 18:13:36 GMT

I'd add on a "recirculating sand filter" using quarter inch gravel - give the system more surface area for the nitrfiers to attach themselves and they will.

Regulators are interesting. Isnt the MDL for ammonia either 0.1 or 0.5 depending on what method you choose? I'd ask them what Std Method Test they require to measure compliance with 0.06 ppm.

I dont think a wetland is the answer - organisms will attach themselves to plant roots, nitrify the ammonia and the plant will use the NOs as a source of N for plant tissue and then die and rot from organic N to ammonia and ........ How can one "control" the process if one isnt the master of the N cycle in this case.

I have heard of ammonia this low in some pristine streams but I also hear the M word associated with these situations.

RE: high ammonia in my SBR plant

bugwisperer — Sat, 20 Oct 2007 18:01:03 GMT

We have twin 50K GPD SBRs in a higher elevation area and have maintained nitrfication through the winter even though reactor temp has been in the range of 2.8 to 4 degC. Ammonia is 55-60 ish. We run MLSS about 5,000. We also fabricated several "baskets" with fine bubble diffuser in bottom with the plastic pasta wheels in the baskets to increase our bug mass while not increasing MLSS any further.

high ammonia in my SBR plant

biker bob — Sat, 18 Mar 2006 21:00:27 GMT

I am a new operator of a sequencing batch reactor plant in New Jersey.

I am having a problem with high ammonia in my effluent during cold weather.

I am also having a problem with the units shutting down for no reason.

If anyone can help me I would be very thankful.

RE: aerated rock filters

bugwisperer — Sat, 20 Oct 2007 17:53:37 GMT

I think what we are talking about here is fixed film. Add fixed film to the process since we dont have a formal MLSS in a pond process and we grow bugs on the film. The nitrfiers are especially appreciative of this if you provide the fixed film at a point in the process where CBOD reduction is all but achieved.

Rock filters have been know to plug if stone supplied is not washed at the quarry; I believe Illinois requires it (post 1989 I think). The orignal idea of rock filters was to provide a psuedo tube settler to reduce algae in discharge as I understand. Dont think they worked.

There are some folks who have developed a concept of aerating rock filters by sinking plastic pipe wells into the rock and dropping aeration in at these points. But, the problem is how does one move the aerated water throughout the filter? I am presently trying several aspirating aerator mixers at the face of a rock filter to see if I can carry DO through it; we'll see.

My issue with them is how do i keep them from ultimately plugging? I aerate, grow bugs, they die and slough of and I cant clean them out. With a floating curtain type of fixed film system the bugs slough off but I can move my curtains.

Mark

aerated rock filters

Casey Wichert — Wed, 12 Sep 2007 16:55:44 GMT

Does anyone have any experience working with aerated rock filters as a means to polish pond system effluent? I'm considering using it for a small pond system in CA as a means to lower BOD, TSS, and NH4. In particular I'm interested in any design parameters such as depth of media, volume of media, etc.

RE: How to lower ammonia level in an sbr plant

bugwisperer — Sat, 20 Oct 2007 17:35:46 GMT

Laurie,

I read through this a bit quickly and it does appear that forum members are keying in on DO as a problem in basin 2. I would agree and add that depending on your mixed liquor conc a 2 to 3 to 4 ppm DO may not be adequate to effectively use all your nitrfiying organisms in the floc structure. If your MLSS is in the 4,000 to 5000 ppm range then your DO is going to have to be I'd say 4.3 to 4.5 ppm minimum. I'd shoot for 2.5 if your MLSS is 2500-3000. As you start to go from 3000 to 4000 and upwards your DO is going to have to go up to into the mid to high 3s. The reason is if you think of the floc structure as a tennis ball, most of the nitrfyng organisms have incorportated themselves deep within the tennis ball. So, until carbon is consumed by the heterotrophic organisms and this DO demand subsides, its a tough nut to crack trying to get DO into the center of the tennis ball to make the nitrifiers happy. The heterotrophs are opportunists and they suck up the DO on the surface of the tennis ball and act almost as a DO barrier to the poor nitrifiers. So if you have 2 or 2.5 parts DO in the bulk liquid you may still have 1 ppm or less on a microscopic level deep within the floc structure (tennis ball). The nitrifiers will be very discouraged. Under these circumstances you may need a 4 or 5 ppm DO in the bulk liquid to achieve a high enough driving force to achieve the mass transfer of DO deep into nitrifier town in the center of the ball. In a past life I did a little work with pure culture nitrifiers and was able to observe ammonia reduction versus DO concentration over time. DO was cyclicly applied - little aerator "on" at DO = 1.5 ppm and DO off at DO = 5 ppm. The sample of pure culture and ammonium chloride (and sodium bicarb and macro and micronutients) was mixed and ammonia conc was monitored via ammonia probe. It was interesting to note that ammonia reduction versus time was linear above 2.5 ppm in this particular sample of pure culture. At DO = 2.5 ppm the ammonia probe flatlined (no ammonia reduction) until the little aerator tripped back on at DO = 1.5 ppm and raised the DO. As soon as DO surpassed 2.5 ppm ammonia started to drop again linearly. The point I am trying to make is that the heavier the organism concentration the more difficult it is to insure that adequate DO (and mixing impacts as well to a degree) is available for 100% of the organisms in the process - to drive DO into the deep recesses of the floc structure in a "heavy" mixed liquor one needs to increase the driving force and mass transfer rate by increasing the bulk liquid DO. This why many times, particularly in the summertime, if ammonia starts to go up, wasting heavily will bring ammonia back down. Yes, we are decreasing the bugs in the process including our nitrifier friends but nitrifier numbers is not the problem. The problem is inadequate DO for the MLSS we have. Reducing the bug mass and in turn the endogenous demand allows the DO in the bulk fluid to come up, increase our driving force and mass transfer rate and greatly increases the mass of nitrfying organisms which have the DO they need to do their thing, even in consideration of the pounds we actually wasted from the process.

As a side note - I guess you have a total N limit or desire to have a mix cycle in the beginning to drive nitrate down so you dont get popping in your settle cycle. If your nitrate is very low in number 2 basin and ammonia is high you may want to temporarily elimiate your mix cycle and make it all react or aerate - ie, we dont need to mix to get rid of nitrate since we have none to begin with. Throw your time at aeration. You may only be doing a little bio-p action in the mix cycle.

I may have caught wind that your aeration system may be a jet system (big centrifugul pump with blower adding air in at the jet manifold in the basin). Sounds like a jet-tech SBR system maybe? Anyway, your manifold jet nozzles may have some clogs. You might want to compare the running amps on the pumps between basins - it may or may not provide a clue depending on whether the piping is largely similar.

If you have air piping flexibility to use basin #1 blower on basin #2 it might exclude the blower being an issue.

sounds like your alkalinity is OK. If you have 80 ppm going out the door you're good. Sodium bicarbonate is an excellent source of alkalinity and you cant overdo it relative to pH - you're only going to go to 8.2 or so at most even if you mess up and overdo it.

Mark

septic mixed liquor

VFP-63 — Thu, 13 Sep 2007 21:36:50 GMT

Does anyone know how little an amount of phenol it takes to kill or wound ML critters.

How long does it take to recover after being hit with the substance.

We only have the use of one small blower at a time.

We have a citrus packing plant upstream that uses a cleaner to remove wax from the equipment after x amount of oranges has been packaged.

We've tried to catch them but it's a hit and miss situation. We only go to the small plant once or twice a week. Avg daily flow .35 MGD.

We're trying to buy a microscope to view the bugs but haven't scraped up enough money as yet.