Question about Sludge

I have been doing more research, finding that there are some very strong anti-sludge sites on the net. I can certainly see some of the bias that comes through, so I began checking references and citations.

The first thing of importance is a read of the actual EPA regulation that forms the "safety net" That can be found here:
http://ecfr.gpoaccess.gov/cgi/t/text...1.2.41&idno=40

To my untrained eye, I'm seeing stated limits on about ten metals, a differentiation between class A and class B biosolids, limitations on active fecal coliform and limitations on but not exclusion of salmonella. I do NOT see any mention of endocrine disruptors, medical and prescription drug residues, or a number of other possible chemical compounds. This is cause for concern.

I do see that when dumping or spreading is "high dose" (my words) that the public access to the area is required to be not allowed for a year, and if it is "low dose" (again, my words) be limited for 30 days. That is prudent, and may even be overkill, but the very requirement is screaming at me that the biosolids are NOT considered totally safe within that time frame.

Individual states may have regulations that are more stringent, but the EPA sets the minimum regulation. Enforcement is an entirely separate subject. From the experiences related to me, I would say that it is reasonable to say enforcement is "spotty."

Further searching found this:
http://webcache.googleusercontent.co...ient=firefox-a

It contained this comment:
"Frequently, nearby residents object vigorously to the
practice of landspreading sewage sludge, and both local
residents and the Archer city commissioners opposed continued
landspreading of biosolids and Whistling Pines Ranch[19]. The
safety of landspreading sewage sludge, which may be toxic
because of heavy metals, radio-nuclides, pathogens, and
untreated organic chemicals, is highly questionable [20, 21, 22].
Some of the organic chemicals in sludge are known endocrine
disruptors such as those that caused reproductive problems for
alligators in Lake Apopka [23, 24] . The EPA regulates only ten
pollutants out of many thousand found in sludge"

The reference for the last statement was Wikipedia. I searched but could not find a corresponding statement in the Wiki article, but did feel the article was reasonably good at providing some basic information. That article is here:
http://en.wikipedia.org/wiki/Biosolids
I won't quote Wiki however, because of the nature of the resource.

After having read the EPA regs, considering the spotty enforcement, and noting the numerous negative comments and complaints, I have a more negative view towards the current disposal methods. Sorry, Cabin Fever.

The benefit to farmers appears to be a low or no cost source of carbon matter as a soil amendment, with some free nitrogen and phosphorous thrown in. I'm certainly aware of manure spreading, it has been used on the family farm in Vermont for well over 100 years. I'm not inherently against the concept.

For me, here is the rub-
When cattle manure is spread, it comes from a limited and controlled and observable source. To a lesser extent, the same is true of spreading chicken litter. The possibility of active fecal coliform and salmonella don't bother me tremendously. With chicken litter, the estrogen-like (bad term, but more easily understood) soy waste from the chicken feed is a mild concern.

Municipal sewage is NOT a limited, controllable, or highly observable source. It can and does contain - waste paint and thinners from washing brushes, photographic chemicals, cleaning chemicals and solvents of all types, medications, illegal drugs, anything that can be ground in a kitchen waste disposal, auto and lawn equipment oils, fibers from all sorts of laundered items, and a host of other items. And that ONLY covers residential wastes.

Placing the semi-processed sludge created by such wastes on food crop land is, to me, irresponsible.

There are three alternatives that I can readily see. At least one of them runs at odds with the Al Gore crowd.

1. Placement in landfills. This allows recovery of some carbon as methane, which can be used as fuel.
2. Placement in dry areas with minimal contact with water or food crops. Many biotoxic materials have existed on earth in this fashion since before man came on the scene.
3. Burning in waste-to-energy incinerators. This is generally thought of as a zero gain, since the bio-solids contain a significant amount of water. Further extraction of water prior to incineration could change that. The other purported negative is the addition of CO2 to the atmosphere. This is a feeble argument at best.

In short, for me, I am having to reluctantly join the eco-nuts on this one, and say that municipal sludge spreading does NOT appear to be safe or reasonable, especially since there are alternatives.

No reason to be sorry Harry

But, I am not going to get caught up in a no-win debate that will just end up with me and Mr. Bynum referencing dozens of excerpts from various technical sources....how boring is that! I am sure that we could both fill pages and pages with scientific mumbo jumbo that is confusing to the layperson. Would all of our diatribe actually sway you to one side or the other of the biosolids recycling issue?

Why would this be a no-win debate? Because I cannot prove that there is zero-risk associated with the recycling of biosolids. And hopefully, we all realize that there is never a guarantee of zero-risk in anything we do or in any of the decision we make as humans. With that said, be assured the overall, long track record of biosolids recycling in the USA shows that it is a safe practice when regulations and Best Management Practices are followed.

What do I suggest? When I’m faced with a decision regarding an issue....especially an issue that might be way over my head in technical information and jargon....rather than investing hours and days trying to understand it, I look at who are the people and organizations that support the two sides of the issue. The EPA, the USDA, the FDA, state agricultural extension, state environmental departments, and municipal wastewater treatment agencies encourage the beneficial use of biosolids. These governmental organizations have nothing to gain by supporting biosolids recycling. To see who supports the other side of the issue, I encourage you to read the websites that Mr. Bynum has referenced: www.deadlydeceit.com and www.thewatchers.us Draw your own conclusions on which organizations are using sound science and research to educate and inform and which ones are using fear mongering and emotionalism.

Lastly, we should all understand that WE are the problem. We all produce wastewater that must be treated. When we are pointing fingers at the municipal wastewater treatment plant and inferring that they are the cause of the problem, we are actually pointing fingers at ourselves. That wastewater treatment plant exists because of YOU and me. Don’ t think that just because you’re on a septic system that you are not contributing to the problem. Where do you think YOUR wastewater is going? It goes directly into the environment via your drainfield. Where do you think YOUR sludge goes when your septic tank is pumped? It either gets land applied directly or it goes to the municipal wastewater treatment plant where is gets treated and then land applied as biosolids. Let’s not be hypocrites.

And speaking of municipal wastewater treatment plants, think of this question. Who are the real environmental heroes when it comes to taking care of the environment and reducing pollution? Is it the over-zealous environmentalists who point fingers and preach that we’re doing it all wrong? Or is it the men, women, and neighbors who operate our local wastewater treatment facilities? If wastewater and biosolids were so toxic who in the world do you think would be affected first? It would be these people who handle it every workday of their lives! And guess what, studies have shown that these people are more healthy than the average population. IMHO, the real environmental heroes are those who turn polluted wastewater into water clean enough to fish and swim in and produce a product (biosolids) that is used to recycle organic matter and nutrients back from whence it came. Yes, these are the real environmentalists! They are doing something about it.

I think I’ve said enough. I want to leave this discussion with some concluding remarks made by a committee of National Research Council of the National Academy of Science after being assigned to review the history, technical literature and regulations regarding the reuse of wastewater and sewage sludge (biosolids).

“In summary, society produces large volumes of treated municipal wastewater and sewage sludge that must be either disposed of or reused. While no disposal or reuse option can guarantee complete safety, the use of these materials in the production of crops for human consumption, when practiced in accordance with existing federal guidelines and regulations, presents negligible risk to the consumer, to crop production, and to the environment. Current technology to remove pollutants from wastewater, coupled with existing regulations and guidelines governing the use of reclaimed wastewater and sludge in crop production, are adequate to protect human health and the environment. Established numerical limits on concentration levels of pollutants added to cropland by sludge are adequate to assure the safety of crops produced for human consumption. In addition to health and environmental concerns, institutional barriers such as public confidence in the adequacy of the regulatory system and concerns over liability, property values, and nuisance factors will play a major role in the acceptance of treated municipal wastewater and sewage sludge for use in the production of food crops. In the end, these implementation issues, rather than scientific information on the health and safety risks from food consumption, may be the critical factors in determining whether reclaimed wastewater and sludge are beneficially reused on cropland.”

__________________
This is the government the Founding Fathers warned us about.....

Cabin Fever does have a point. However, I must address his statement: "The EPA, the USDA, the FDA, state agricultural extension, state environmental departments, and municipal wastewater treatment agencies encourage the beneficial use of biosolids. These governmental organizations have nothing to gain by supporting biosolids recycling."

EPA, FDA and USDA signed a federal policy in 1981 to promote treated sewage sludge and effluent as a fertilizer and irrigation water for fruits and vegetables because our water was being contaminated. They did know bacteria would survive for 72 weeks on grazing land and treatment systems were releasing antibiotic resistant bacteria. They were to use the Land Grant Colleges and University agricultural extension services to educate farmers. They ignored the fact that Congress in its wisdom defined sludge as a solid waste which must be disposed of in a legally permited sanitary landfill. In
1993, EPA converted the 1981 policy into the part 503 sludge Rule (not biosolids rule). There were two parts to the sludge rule of interest here. The first was the self-permitting section for land application under part 503.13 which allowed chromium pollutant levels of 3,000 ppm. Later chromium was removed from the regulation because it could not be disposed of under a legal EPA permit in the land disposal section of sludge the rule, part 503.23, which only allows a maximum chromium pollutant level of 600 ppm.
http://deadlydeceit.com/503-13.html
http://deadlydeceit.com/503-23.html

If you read 503.4 of the sludge rule you will find that there is no requirement to comply with any law unless sludge is disposed of in a municipal solid waste landfill unit under the CWA/RCRA.
http://deadlydeceit.com/503-4.html

As a solid waste, sewage sludge is a point source of pollution and must be prevented from entering our surface waters -- unless it is dumped on agricultural land which is exempt from the CWA requirement to prevent stormwater runoff. In effect, our states are creating solid waste open dumps which are prohibited by RCRA. The trick is that the states are responsible for stopping open dumping.

It is all about money for Land Grant coleges and University studies. After finding bacteria survive on grazing land for 72 weeks, antibiotic bacteria are being created in treatment plants and there is no treatment process to destroy bacteria, another 100 million or so on studies is not going to change anything. The farm is the last place without regulations, but that is going to change shortly because of the explosion in food contamination caused by EPA, FDA and USDA. We can't blame people like Cabin Fever because he was simply relaying what he was taught.

Gentlemen, I appreciate that both of you have exposed points of view in the finest traditions of debate. If only our politicians and media could be so well spoken and smart.

I certainly agree that nothing we do is zero risk. I've been playing that violin myself for years against the cacophony of over-regulation, laws invoked at the behest of special interest groups, and the like.

I also am reminded of a comment made by a doctor who lived long before me in the town where I grew up. When lauded about his contributions to the health of the community, he backed away and said "The person you should be thanking is not me, but Mr. X. who for years has been fastidious in filling in the filled outhouse holes so that they were completely sealed, and digging new ones that were safe and properly located."

Unlike back then, we have chemical compounds today that have never existed in nature. We only have a brief window of experience with most of those. Will a few of them be found to be bad apples? I have no doubt that a few will. The percentages of chance alone seen to indicate that it is a probability rather than just a possibility.

If the alternatives were not there, or seemed LESS reasonable, then I would be lockstep with you, CF, that everything we do has inherent risk. I'm not ready to say that yet, precisely because the other possible handling methods appear to involve less risk. In other words, I'm willing to walk around the pasture with the breeding bull who may or may not be friendly, in favor of walking through the shoats in the pigpen.

I understand the strong feelings on both sides of the issue. Ultimately, I'm going back to the idea that if you HAVE to do biosolid spreading, do it in your own yard. That, to me, indicates personal responsibility and independence.

Again, kudos to a GREAT debate.

Harry, you are a gentleman and a scholar.

There is terribly little benifit to farmers in 'carbon addition'. You just can't build up organic matter on 1000's of acres by hauling it in - way too costly, takes way way too much N out of the soil. I understand this is common on garden plots - who don't realize the actual costs of doing such! The sum total of the sludge is in it's N, P, K, and micro nutrent content. Cabon value = very very close to nill. This stuff is applied very thinly, several 1000 gallons per acre is all - much of that is water so really very little carbon. I think your book-reading got in the way of reality on this one.


It has been my understanding that sludge cannot be used to grow a food crop????


1. Filling landfills with sludge so you can generate a bit of methane seems a terrible waste of resources to me. There is far more value to the N,P, & K for growing crops, than the dribble of methane you'd get. While wasting landfill space, which is a very limited resource with many worries. Blah.

2. Where do you live, that there is a 'dry area'??? There is none where I live! Not a realistic alternative at all. Basically you are describing - a landfill. See #1.

3. Burning releases the heavy metals into the air. Scrubbers to remove such are terribly expensive. Burning sludge, which is a wet product, is a zero-gain deal, takes as much to dry it as the energy it gives off. So, you are not gaining anything at all, wasting a resource (the fertilizer value), and creating air pollution.

You seem afraid of the bugs in the poop - any homesteader or farmer tends to be knee deep in poop from time to time if they have any livestock - or kids. Certainly one needs to safeguard against plagues & such, and keep poo seperate from the food. But - if you've ever used a public bathroom you've been around the same bugs as are in sludge. These bugs are all around, in small amounts, and we do fine.

I'm not sure I understand, and certainly don't share, your fear of wehat is basically normal bugs that appear in nature. We need to handle concentraded amounts of them with some care, but spreading the sludge on farm fields and used to grow animal feeds the following yewar which are fed probably another 6 months later which are sold at a later time as food seems to remove us humans from the immedeate danger you see?

I would hate to see a good resource - locally produced fertilizer - be sent to a landfill or burned - and totally wasted. Be a shame to waste body waste.

The heavy metals issue & proper testing - those issues I have more reservations about. We should be able to handle those; but cheating seems to be a popular human activity....

Just friendly debate with you, don't mean to question your seriousness or thinking on the topic.

--->Paul

Jim, I don't know if you joined HT just to bring your expertise to this topic but I'm glad you're here. Your level-headed and informative posts are greatly appreciated, and the fact that you can post the information without making a dig at the opposing side shows who is really allowing folks to "draw their own conclusions" and who is trying to sway opinion with poorly concealed bias not only regarding the topic but also regarding people in general. Thanks for keeping it about the facts.


For the OP, a timely article that might interest you: http://www.nytimes.com/gwire/2010/08...l?pagewanted=1

__________________
Anne
Give me a sweet home set among the trees,
With friends whose words are ever kind and true.
-Phoebe Carey-

LONE PINE FARM
Barnesville, PA
Boer goats, Angora goats, Eclectic mix of poultry

Rambler, no the bugs don't bother me. I've cleaned enough flooded business bathrooms and cleared enough drain lines that it isn't an issue for me. I'm more concerned with incidental stuff that gets flushed. I won't rehash that, since I've detailed my concerns in previous posts.

Landfill space is ONLY limited because of political considerations. I'll repeat something I've said earlier elsewhere, that ALL the waste for the U.S. could be contained in a SINGLE landfill twelve miles by twelve miles in area. If it wasn't for transportation issues, and the energy used, I could just about guarantee that such a resource would have the best recycling in the world. The simple scale alone would make it profitable to do a thorough job on the incoming waste stream.

1. The "dribble" of methane represents a significant amount of energy over a long period of time. Understand that since methane is considered a far worse greenhouse effect contributor than carbon dioxide, and methane production can easily occur in wet areas or from decomposition, there is some benefit to controlling it (for those who are into such things).

FWIW, in composting to get sludge ready for use as an amendment, I noticed that up to 1/3 of the mass already goes into the air as carbon dioxide. Turn that 1/3 into more methane that can be burned as fuel and figure the quantities of waste being discussed, and it starts to add up.

2. There is no dry area in Alabama, unless you include "dry" counties. I was not suggesting storage in dry areas as an "only" solution, but as an effective alternative to spreading it on cropland. The west has significant dry desert areas. For California, the non-park area around Death Valley (including the off-limits military target range) could be a viable storage or disposal area, IF the eco-nuts could be satisfied. I'll admit that chances of that are slim to none.

3. Burning does not have to release heavy metals. Scrubber technology is already in place in the waste to energy plants that exist today. That, coupled with fluidized bed burns, minimizes toxins and metal release. The bugaboo is the Gore crowd and the carbon dioxide emissions.

I do need to address that briefly, since it is a red herring that a lot of people have claimed to be a real issue. Carbon. Carbon as it is expressed in sewage and mulch and many other organic forms will end up in the atmosphere whether you burn it fast, or put it on the soil and allow the buggies to feast and fart. Putting sewage on a field is only partly a carbon sink (I note your complaint that carbon isn't as much the "important" part of sludge as the chemicals, and in part agree. However we are dealing not only with fact but public perception.) Give a sludged field a few years, and unless there is a constant plant cover, and additional plant material that is allowed to lie fallow, that carbon will end up in the atmosphere without being continuously replaced.

You can burn sludge fast in an incinerator, or you can "burn" it slow as biofood. It ends up in the air either way. If we stuffed it down an abandoned coal mine, then yes, we would be sequestering some carbon. But don't fall for the media claims of saving the world from global warming by putting sewage sludge in the soil.

"Wasting" waste. That is more than just a humorous abbreviation of your "take" on the alternative ideas. It deserves a considered response. I think you are correct that it is possible to under-utilize what could be a resource. Pedantically, I'm not sure that it is even possible to "waste" waste however. We would then have to worry about wasting waste waste, and my brain is beginning to hurt from the circular reasoning.

Having access to history, but no access to the possibilities of the future, we tend to be arrogant in our assessments, especially in the area surrounding technology. I am more inclined to think that the waste we store will become the resource mines of the future, simply because the technology will be so improved that heavy metals will easily be gleaned from landfills, carbon, phosphorous, and other elements will be reclaimed, and in a world where some materials have been exhausted from easily mined areas, the landfills of today will be the gold mines of the future.

Spreading sludge allows some additional plant growth. I'm not sure what the overall energy footprint is compared to converting natural gas into nitrogen fertilizer. There is energy consumed in getting sludge to a suitable state, it is on the level of a 3-2-0 fertilizer, and the conversion of natural gas and waste products from gas making into agricultural materials is efficient enough for it to be inexpensive, while creating highly potent and lightweight fertilizers that are inexpensively shipped.

The fertilizer value is primarily the N&P portion. The K can be less than the lead levels - source - http://pubs.acs.org/doi/abs/10.1021/jf60226a069 Other than N & P, Ca (calcium) and Fe (iron) are significant in the cited reference. Cd and Pb are not generally considered micronutrients, but are part of it. A buildup of the zinc and chromium may not be good for row crops, which brings the value of sludge as a fertilizer down somewhat, since less affected crops would be the less valuable ones like hay or grasses.

By the way, do you see a disconnect in your statement "Burning releases the heavy metals into the air." and your desire to place those same heavy metals directly on cropland? Do you consider the temporary release into the air (lead does not fly for long) more dangerous than the same lead when placed on cropland? If so, please state your reasoning.

Oh well, enough time on the subject. You brought up good points. My counterpoints don't mean your points aren't valid, they simply are an attempt to bring balance.

If only for the transportation costs & 'not in my back yard' issues, the one centralized landfill is an interesting idea, and I've often wondered if we won't be reclaiming some of the landfills in the future to get some valuables out of them.

Seems landfills tend to be somewhat small generators of methane, and to plumb them up, and pipe them up to be a useable source of energy is not real efficent. Doable, but I'm thinking the fert value of the sludge the following year is more than the methane value - I'm guessing? - 20 years down the road.

I have often chided people about the gas release of products when burned or used, vs letting them decay naturally. You're one of the few people who seems to agree with that. I hear you, agree.

My fields are heavy yellow clay or alkilie peat ground that is almost burnable. This after 100+ years of haevy tillage, organic matter is 4% and up. So my background is clouded, as to what carbon means.... It is just real tough to add meaningful amounts to large fields. It's not ecconomical to add enough to matter in 2 years, so - I kinda slide over that one as not worthwhile $$$$.

Any sulfur in sludge? That has become a big shortage in the soil of grass crops (like corn) since they cut the sulfur in diesel fuel. Moly is another. Can't think of the 3rd common trace fert - oh, boron. These are applied something like 5-15 lbs per acre - that's a pretty light dusting. But manures, and sludge I'd think, offer these & others. I know I wish I had more manure for my crops, it certainly is a fuller fertilizer than the commercial stuff. We need the commercial stuff, but it does come up short at times.

Sludge is also slow-release on the N, can help fertilize for 2 years really.

Around here, the sludge is pumped through draglines - hoses - and applied within a couple miles of the plant, or hauled in tankers 4-5 miles and applied. I live by communities of 15,000 or less with much farmland around, so transportation is a minor cost, compared to developing methane transport. That's a 'here' deal.

I hate having pollution in the air. A lot tends to float around the globe. You can't clean the whole air. Effects so many.

Don't like pollution in the water - it too flows all over the globe.

Spreading sludge on the ground - actually injecting it 4-6 inches deep is how they do it here - and you can test the soil every few years & see what is building up, or what is not building up - easy to control. Ground application in fairly light applications per year makes watching pollution buildups very easy. If you mess up it's limited to a 1000 acres or so, which is manageable.

Releasing that same pollution into the air or water bothers me much more. Very hard to control or cut back when it's so variable.

Ground application seems lest of a problem, much easier to control the results.

Thanks for the discussion. Not trying to change anyone, just offering my view, good or bad as it is. Enjoyed your humor.

--->Paul

I still don't have a definite opinion but this has been really informative and interesting!

Personally, I smell a rat with an agenda.

__________________
“I would remind you that extremism in the defense of liberty is no vice! And let me remind you also that moderation in the pursuit of justice is no virtue.” Barry Goldwater.
III

bloogrssgrl, most people who get involved in the sludge issues are there for two reasons. The first are those good people who wanted ocean dumping stopped and who think sludge is a great fertilizer, dilution is the solution to pollution, there are no harmful chemicals, pathogens are killed and if there was any danger EPA wouldn't allow its use on agricultural land. The other reason is those good people who have seen there environment harmed by sludge and those people who understood ocean dumping was stopped because that environment was being destroyed.

The canary in the mine for this issue was dairy cows in the late 80s and early 90s. Zander dairy in Washington, Roller dairy in Missouri, Ruane Dairy in Vermont, Boyce Dairy and McElmurray dairies in Georgia. Currently in Alabama there is a lawsuit in progress because after 12 years of sludge use EPA found alarming amounts of “unregulated contaminants” in the soil of farms that received the biosolids.

During that same period we had a farm that collected runoff from a municipal sludge farm. Between 1989 and 1998 we observed the contamination and studied the literature and the laws. While the few chemicals EPA regulated didn't appear to be a problem overall we found that E. coli and Salmonella were at extreme high levels compared to fecal coliform. At that point we quit farming.

The foremost reason given for putting sludge on agricultural land was that we were running out of landfill space and no new ones were being built. A strange conclusion, since the federal government owns over 260 million acres.

The real reason is that liability is transferred to those who use sludge because it is very difficult to prove cause and effect. On the other hand consider lead. You need an EPA certified contractor for lead abatement of older homes and lawns, but EPA allows high levels of lead in the sludge you buy or that is given away to use around your home and farm.

I had to chuckle when I read this at first. My DH is the site manager for our local landfill. They use "sludge" as part of their road building for the cells at the landfill. However this sludge is not what you guys are referring to. This is foundry sludge, from the local GM foundry. And yes, the EPA has approved it for use, they're not just sneaking it in.

As far as this comment:
" Seems landfills tend to be somewhat small generators of methane, and to plumb them up, and pipe them up to be a useable source of energy is not real efficent. Doable, but I'm thinking the fert value of the sludge the following year is more than the methane value - I'm guessing? - 20 years down the road".

If you were referring to landfills, you'd better think a lot farther out than that. They recently had to reopen an old cell where DH works, and there were newspapers in there from 1970 that we're still intact with the print clearly readable, lol.

__________________
S-J Farms
http://s-jfarms.com

Jim, thank you again for the response.

Coming from and area where sludge is an issue not quite so much in regards to farmland but more so for mine reclamation projects, it's a concern to me no matter where it is placed. Each area and inteded use comes with it's own set of issues.

Can I press you for some more information? What end product (sludge-ly speaking) is one generally left with when using sludge in an anaerobic methane digester? The reason I ask is that we have a local treatment plant as a neighbor and, in an effort to possibly take lemons and make lemonade, we toyed with the idea of buiding a digester and contracting with the plant to take the sludge. As of now, they contract with a company that comes in and pumps it out to haul it away to finish the process. It is not, as far as I am aware, processed to a point at this local plant where it is considered safe to spread anywhere. The main thing that has held us back from pursuing this is the byproduct and responsible disposal that would then be in our hands.

Edited to add: The farm in Alabama that you mentioned - do you know if they were taking Class A sludge or Class B?

__________________
Anne
Give me a sweet home set among the trees,
With friends whose words are ever kind and true.
-Phoebe Carey-

LONE PINE FARM
Barnesville, PA
Boer goats, Angora goats, Eclectic mix of poultry

bloogrssgrl, there are two types of digesters aerobic and anaerobic. The first makes use of bacteria that use oxygen and the second makes use of bacteria that don't use oxygen. The trick is that these are called aerobic and facultative bacteria. Basically what that means is that they digest the organic materials whether there is oxygen present or not. It just takes a little while to convert from one phase to the other. Sludge is the biofilm resulting from the actions of the bacteria binding the fine solids together.

Class A or Class B is not relevant in regard to the Alabama sludge as the Class is determined by the fecal coliform numbers. The fecal coliform numbers only indicate the assumed numbers of individual bacteria placed on the test media at the beginning of the test. The lab technician actually counts colonies of thermotolerant E. coli/Klebsiella at the end of the test and reports them as either colony forming units or most probable number. Thermotolerant means they are looking for bacteria that would be growing at 112.1degF long after you are dead at about 108degF. The bacteria you are concerned about grow at 98.6degF.

I neglected to mention that when bacteria digest organic material they may create methane, alcohol, hydrogen sulfide, etc. Any time there are odors bacteria are at work.
Some of the odors can be deadly. http://thewatchers.us/odors.html