Sewage sludge for horticultural use is usually allowed to sit for an extended time (during or after composing on granular bark or wood chips) for the purpose of viral deactivation. Six months rings a bell, but I am really not sure of the time involved.

Here's a thread that might be helpful:

http://forums.gardenweb.com/forums/load/orglawn/msg0616354424488.html?38

Look for the December postings in that thread.

Thanks for the link, ZoysiaSod. All of the points are well taken -- PCB's, dioxin and pharmaceuticals can still be present in treated sludge and nobody tests for them.

Anyway, the stuff we are thinking of getting is not all sludge. They also use manure and green waste and it is composted, according to their web site (linked below). It comes from a farm community (Santa Maria CA) with not much in the way of industry. They test it at Soil Control Lab in Watsonville for everything the EPA regulates.

There are a lot of industrial farming operations here in Central California, using a host of nasty fungicides and herbicides. It's hard to decide which poison is best!

BTW we have our garden on a green manure rotation which really helps. But the soil is very sandy so the compost addition is an effort to increase the organic matter percentage and hence the CEC.

Here is a link that might be useful: http://www.engelandgray.com/compost_quality.asp

What is in sewage sludge depends on what travels down the waste stream. Many places require industries that could introduce contaminates to pretreat their waste to remove those, however households often dump unwnated stuff into that waste stream without thinking of later consequences, or a "this little bit won't do any harm" mindset.
So whether to use compost that consists of sewage sludge depends on the source of that sludge. Know also that some of those heavy metals are being found in storm water runoff that is flowing into our streams, rivers, and lakes without any treatment.

I thought that sludge had to be analyzed for a host of contaminants under the EPA Biosolids Rule in order to use it, but it may be limited only to metals.

There have been surveys of a much wider range of contaminants in sludge samples nationwide, as seen here:

http://water.epa.gov/scitech/wastetech/biosolids/tnsss-fs.cfm#results

But what those results MEAN - beyond the fact that many chemicals were detected - is another question that I am not sure has been answered.

EPA decided in 2003 not to regulate dioxin in sewage sludge on the basis that the amounts present were not a particular risk and had been declining for years.

http://yosemite.epa.gov/opa/admpress.nsf/b1ab9f485b098972852562e7004dc686/209dab87e1b0a8b785256dc20050c977?OpenDocument

And there are emerging contaminants - like the polychlorinated diphenyl ether flame retardants - that we don't know much about at all yet, and it will be years before a 'safe' level for soil is known.

I haven't had to answer the question of whether I'd use it myself because we have other local sources, but given what I know, I *might* use it on my lawn, but not my vegetable garden, just to be safe.

Natural vermiculaite may have a significant amount of asbestos.

Natural phosphate may have a significant amount of uranium.

Chicken manure up to recently could have a significant amount of arsenic (I assume, because they fed arsenic to the chickens at therapeutic doses).

Avoiding risk at relatively low levels is not easy.

Sewage sludge, including compost, contains infectious human and animal prions which can cause transmissible spongiform encephalopathies (mad cow disease, etc.)

Alzheimer's Disease (AD) and sporadic Creutzfeldt Jakob Disease (sCJD) are sister prion diseases, transmissible, infectious by medical equipment, (scopes, etc.) dental and eye equipment, blood, urine, feces, saliva, mucous (aerosols: possibly by coughs & sneezes) Doctors frequently misdiagnose AD and sCJD one for the other. The symptoms and neuropathology are almost identifical.

Right now the US is in the middle of a raging, always fatal, prion disease epidemic: There are over 6 million victims of AD and 1 million Parkinson's Disease victims, with a new AD case every 69 seconds !

Recent research (October 2011) by Dr. Claudio Soto, et al, University of Texas Medical School, has confirmed earlier research which found injecting Alzheimer's brain material into mice brains caused infectious prion disease.

http://www.sciencedaily.com/releases/�2011/10/111004113757.htm?utm_source=fee�dburner&utm_medium=feed&utm_cam�paign=Feed%3A+sciencedaily+%28ScienceDa�ily%3A+Latest+Science+News%29

AD and sCJD victims shed prions in their urine and feces. Sewage treatment does not inactivate prions - it concentrates them in the sewage sludge. The US EPA acknowledges that the landspreading of sewage sludge is also a pathway of prion risk for humans and animals (Mad Cow, CWD, etc.)
http://www.alzheimers-prions.com/

EPA NATIONAL WATER RESEARCH COMPENDIUM 2009-2014 lists PRIONS eight times
as an EMERGING CONTAMINANT of concern in sewage sludge "biosolids" , water and manure:
http://www.sludgevictims.com/prions/P�RIONS-EPA-EMERGINGCONTAMINANTSINSLUDGEB�IO.
pdf

"Could Alzheimer's be infectious? " �http://neurophilosophy.wordpress.com/20�06/11/24/could-alzheimers-be-infectious�/

SEE reply posted by:
Dr. Murray Waldman, coroner for the city of Toronto, Canada:
"In answer to the question how would Alzheimer�s (AD) be transmitted, I have written a book "Dying For A Hamburger" that hypothesizes that AD is spread by how we in North America and Europe feed and process meat, mainly beef.
If you study the rates of AD and its geographical distribution, you will find that rates start to soar when a country becomes meat eating (i.e. Japan and Korea in the 1960s) and rises even faster when it adopts a fast food culture (the US and Western Europe in the 50s and 60s) and remains low in vegetarian countries (India) and those without a processed meat industry or fast foods (equatorial Africa)�Murray " hshields@tds.net

Here is a link that might be useful: Alzheimer's, prions and sewage sludge

At one time, epidemiologists thought that steamed bone meal used by rose gardeners had probably caused two cases of "Mad Cow" in humans in England. I don't know if they ever revised that assessment.

Speaking of Mad Cow disease, I have linked an article. I don't know the truth/truths about it, but the linked story might give you some thought.

Here is a link that might be useful: Mad Cow Disease Trail

There is a school of thought that CJ disease, the human equivelant of Mad Cow Disease, can be transmitted to humans through the food chain, particularly if contact by humans is made with brain stem material that might, possibly, be mixed in with blood and bone meal. This is because many of the herds that contracted Mad Cow Disease were fed bone meal as a supplement.
Since CJ Disease is known in human populations that do not eat animal products also the link is at best tenuous. So, how is it that vegetarians contract CJ disease?

I would use for ornamental gardens only not edibles.

I have used the dried granular Sumner Grow on lawns & mixed borders. It's free anytime in Sumner, WA at their recycle center/waste treatment location off Main St/Traffic Ave. toward 410 & the river there. Shovel is provided. I wear a mask as it's dusty.

The odor repels deer (great) & my son (bad), so I can't use too much of it. He mows & helps me with the heavy work. It's not a pleasant smell, so I only apply in October & early spring & let the seasonal rains wash it in. Less smell when I fork it into the mulch layer, but you can't do that on the lawn.

I like the results as we've never fed the lawn anything by compost now & then. Hostas loved it & grew amazing this last year.

Hope that helps ~ Corrine

hshields: If true that is a scary proposition. However, you've quoted one researcher at U. Texas, and a coroner from Canada. In my book this is not enough of a body of evidence yet. If it's true, it will be confirmed by others.

In the meantime, my advice is not to eat sewage sludge. :-]

I work for a waste-water company. We sell the byproducts to farmers. At this time it is only approved by the E.P.A.for hay production in my area. Not for vegetable gardens or direct grazing by cattle.

We do extensive tests for heavy metals, pathogens, and pharmaceuticals before it is distributed. It is no more toxic or harmful than the 10-10-10 you buy locally and more environment friendly.

As an experiment I grew some tomatoes, beans, squash, turnip greens, and corn with sewage sludge in a separate garden. I didn't eat any of the veggies, but took them back to the lab for testing. There were no heavy metals,pathogens, or pharmaceuticals present in the veggies.

I'm not saying it's safe. The E.P.A. hasn't approved it. But I would use it.

Thanks everyone. We have test results for this compost. They provide the actual metal content and the EPA limit. The EPA limits are:
Element EPA limit
Arsenic 41 mg/kg
Cadmium 39 mg/kg
Chromium 1200 mg/kg
Copper 1500 mg/kg
Lead 300 mg/kg
Mercury 17 mg/kg
Molybdenum 75 mg/kg
Nickel 420 mg/kg
Selenium 36 mg/kg
Zinc 2800 mg/kg
They also pass/fail test for Fecal Coliform and Salmonella. No test for prions.

I'm thinking this stuff is maybe okay for lawns but not so good for gardens. There's just too many unknowns,

The city of Austin (TX) manufactures and sells compost under the name "Dillo Dirt".
Dillo Dirt is a mix of "composted; yard waste and treated sewage sludge" that they is safe for vegetable gardens (see link).

I would think the brand you are looking at would have a disclaimer stating if it was safe (or not) for vegetable gardens as well.

{{gwi:260493}}

Here is a link that might be useful: Dillo Dirt

The trickle-filter beds in sewage-treatment plants used to have some of the finset looking tomato plants and tomatos you have ever seen. I'm sure some got eaten, but not by me. (I wouldn't be too afraid of what was inside, but the microbes on the outside from aerosols would have been formidable. Still, rather than starve I'd readily wash or sterilize the outside with alcohol and eat them with confidence. Heavy metals are chronic-acting; microbes acute.)

@ gonebananas: I was going to say something earlier and forgot, that the arsenic in chicken manure has to be from some other source, because I can't imagine any therapeutic use still approved, as it is a known toxin for humans as well. It has to be background from some ingredient in the feed, and is concentrated in the manure.

@ wertach: Very interesting experiment on the veggies! It illustrates that even if there are detectable amounts in sludge (or soil for that matter - there are background levels of virtually all these metals) it doesn't necessarily mean the veggies will be toxic, after dilution into the soil and selective uptake (or not) by plants.

@ kivasgrandma: Thanks for those numbers. I deal with safe standards in soil all day long, and it's interesting to note that these are a bit higher than what I use (at the state level) as 'residential' safe levels (including for gardening). But not that much. If one was to replace their whole yard with this stuff, theoretically it would exceed my standards by several times. I don't think I'd want to use it year after year after year on the same piece of ground, but occasional appplications will not have a significant effect on the top 6" because of the dilution effect.

Researchers are going to find something if only to justify their existence. The only way not to be around something that can pass on some disease is to dye.

It's funny that some people think researchers are there only to justify their own existence. The truth is that in order to find answers, questions have to be asked and hypotheses tested. You have to look for something in order to find it. If it's not there, then science (at least, good science) moves on.

I tend to agree with you about the finding of microbes everywhere though - OK, so doorknobs in the office have e coli on them, is that a risk or not? It's hard to know when the newspaper just says "E Coli found in offices nationwide!"

I know you're probably referring to the Mad Cow/CJ thing and not chemical contaminants, but just as an example of how science progresses:

The sludge survey published by EPA that I linked above was designed only to scientifically sample sludges from across the US and find out what was in them and how much. It did not attempt to assess the risk from those levels, and in fact, for many of the chemicals analyzed for (pharmaceuticals for example), no one knows what a safe level is in composted sludge used on lawns or gardens because that research hasn't been done yet. So this was step 1 in a long process of assessing safety and risk. But it has to be done, because "the dose makes the poison". And, chemicals that are not found because they break down in the sewage plant, can be eliminated from further consideration.

So, is that researchers looking for the bogey man under every bed, or a stepwise scientific process?

Googling _ arsenic in chicken _ shows many links discussing As intentionally placed in their feed. I am told by those more involved that this was banned several years ago, or in any event not a long time ago.

The city of Denver contracts with wheat farmers to spread the sludge out on their fields, there is some limit of how much they will use, but off hand, I dunno what it is.

toxcrusadr, You bring up a good point about not wanting to add slightly questionable ingredients to the soil year after year. Perhaps one application would be ok. A very good example of that is this wonderful leaf compost available to me. Trouble is, it contains nearly 10% small rocks. I figured that once was ok, but have screened it otherwise...a LOT of work.

Most soils likely contain a micro amount of lead, arsenic, radium, and etc, but it is the percentage that counts.

Check the load limits for those metals in the EPA regs and you would have to add an inch or more per year for decades or even hundreds of years to reach the soil load limit that is considered safe....not taking into account the mineralization and sabilization of these metals. Class A biosolids are safe for the homeowner to use and certainly safer than the toxin laced sythtic chemical fertilizers that are commonly used.

Gonebananas, you are correct, and I was not aware of the use (former use) of arsenic containing antibiotics in chicken feed. It appears to have been discontinued in the US in 2011.

however households often dump unwnated stuff into that waste stream without thinking of later consequences, or a "this little bit won't do any harm" mindset.

AKA, death by a thousand cuts

OMG, the sky is falling too! Give me a break, the concentrations are so low of those compounds in biosolids that they are considered completely safe. Where is the scientific evidence that they are causing problems from biosolids. Real evidence, not speculation from some occupy wall street fringe group.

Some municipalities have very strict regulations on where, when and how often biosolids can be used. Some even ban it outright. There are also restrictions on what can be grown on land that has had the biosolids applied. Now this may be an overabundance of caution but.

Personally, I would pass on sewage sludge compost.

Lloyd

I'm with Lloyd here. The amount of concern regarding use of biosolids on the part of municipalities trying to limit liability is enough to warrant caution. For me they would be a source of last resort.

A few years ago I was one of the protesters to keep the city of Muncie from spreading sewage sludge on fields a half mile away from me. Also several years ago we protesters stopped that city from opening a land fill about 2+ miles away from me even though it is in another watershed....NIMBY lol!

I would like to see it used in arboriculture, golf courses, city landscaping projects, and the like, but it is still a little sketchy to me to see it used around food crops. Once you've had a child or two, a little poop doesn't bother you much, but a lot of it - especially a lot of other peoples' ...
it's still hard to get past the ick factor.

You all have eaten food that has been grown with biosolids as it has been used in agriculture for years. If used properly, there is no danger....but don't let facts get in the way of "political science."

I would have no problem using humanure from my own family when composted to standards. I just don't trust what other people put into the sewer system.

Lloyd

Well said Lloyd, that's how I feel.

I have no objection to using it on lawns, parklands, tree crops, etc. There are all kinds of places where it could be used with minimal exposure to people.

Yes, that approach is an abundance of caution. I can tell you from my seat in the environmental toxin regulatory community that the science is changing and evolving, and the low level cocktail of man-made and natural but toxic chemicals that we are releasing in wastewater (i.e. rivers) and sewage sludge is one of the things we don't know enough about to give me a real good comfort level compared to a lot of the other toxic stuff we discuss on here. I wouldn't use it on my vegetable garden at this point.

I have read that drug residues are showing up in the water supply. Perhaps small amounts, but when added to chlorines, bromines, fluorines, pesticides, and toxic minerals, we have a cocktail of bad stuff.

@kivasgrandma

You said
"It comes from a farm community (Santa Maria CA) with not much in the way of industry." It is mixed with green waste.

I would use it without hesitation. It's better for the environment and better for your pocketbook.

In fact, get two loads. Spread one load this year and allow the other load to age for one more year. After a year you will have the best possible humus for seed starting, houseplants, potted plants, starting hard-to-germinate tiny seeds like carrots.

IACBTC
Nancy

The devil is always in the details. Caffine is a drug and it too shows up in groundwater affected by septic tanks and stream water affected by sewer plants. Yet few of us would hesitate to use coffee grounds in compost and some people are even fixated with using human urine, without respect to whether said human is a coffee drinker.

That said, hormones and other medicines found in wastewater are possible to probable environmental hazards (to aquatic animals). Can they survive prolonged microbial attack in a soil environment? Can they enter food and cause a problem? Are they anywhere near the natural effect claimed by some for estrogen-immitators in foods we already relish (e.g., soy)? Is anyone who is above suspicion looking at this carefully?

In order to make sewage sludge more usable, the EPA has developed standards. Class A biosolids has been tested and deemed safe for use on food crops.

Different communities have different things in their waste. I would not want to use the solids that came out of a big city treatment plant. I wouldn't hesitate to use the solids that come out of a small rural community with no industrial users contributing to the sewers.