A hot topic, and incredibly complex. One percent of 800,000 tons, the annual output, is 8000 tons. That is still a lot of sludge to be handing out. What else do they mix with the sludge? Do they include shredded leaves, wood chips, sawdust, lawn clippings, kitchen waste, and restaurant waste? What is the relative ratio of the various ingredients? How much time does this material spend in the compost pile, and how warm does it get? I don't understand how the city can responsibly fail to test for pharmaceuticals and certain pesticides. If it is true that cows exposed to this compost later died, then there needs to be an explanation of how that happened. We have to come to terms with municiple sludge. We can't keep hiding it away forever.

There was an episode of modern marvels on the history channel that covered some of this in one of it's episodes. It's been a long time since I've seen it, but basically before it goes out the door it's put through a rotary kiln to ensure a 100% pathogen kill.

Maybe there was something wrong with the kiln.

As stated, I don't think it is the human waste itself that is the issue so much as it is all the other "stuff" that gets washed into the waste stream.

It would be near impossible to test every batch for every toxic substance and pharmaceutical. Most compost tests just look for the basic pathogens and other toxins so anything that is not tested for may or may not be there.

I won't use sludge and I'm even leery of composting manures. If it was from a local farm I trust, maybe, but it's easier to just not use manures.

Lloyd

The industrial 'stuff', meds, and antibiotics that are processed through the disposal system and become the 'sludge' that is composted, are a major stumbling block in the path to finding a way to use that part of our waste....which most folks agree, we must find a way to deal with. The groups that look beyond FREE and GREEN to raise these questions, are doing us all a favor if the disposal folks are forced to find a way to deal with those polutants. The same questions should be raised with animal manure from feed lots, which have a similar load of meds and are sold at super cheap prices.

I am from San Francisco. We have a composting program, but there is no free compost give aways. I would know. As far as I can tell that whole thing about the sewage is a hoax. If they were giving away free compost as a compost wacko, I would be frist in line. I might not take it if it was bad, but nothing is given away. What they make from the green cans, they must sell it somewhere to someone. Compost is expensive, they don't give it away here.

Here is a link that might be useful: composting program

The SF Biz Journal also states that SF has had a give away program.
...snip...."Still, the SFPUC said it's not trying to mislead the public and has literature about the makeup of the compost on its web site and available at its giveaway events. It also provides staff to answer questions at the events. And anyone who feels uncomfortable using biosolids/sewage sludge obviously doesnÂt have to use it, said SFPUC spokesman Tyrone Jue.

"We hold this (giveaway) at the (water) treatment plant and people have to drive in the gates to pick it up," Jue said. "ItÂs not like weÂre going around the city and throwing it up in the air."

The SFPUC said the compost is treated at its San Francisco plant and again at another plant in Merced. It has lower levels of metals and other toxins than commercially sold organic fertilizers and is safe to grow food in, the SFPUC said. And the compost is approved by the Environmental Protection Agency."
http://www.bizjournals.com/sanfrancisco/blog/2010/03/poop_to_hit_fan_well_stairs_really_at_city_hall.html
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The SF Sewer Dept website has a link to a 'fact sheet' on biosolids ... but it is a dead link ... wonder why?
http://sfwater.org/mto_main.cfm/MC_ID/14/MSC_ID/117/MTO_ID/671
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Though not about the situation in SF - this article describes the disposal methods/standards in NH.

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...snip..."There are essentially four options for dealing with sewage sludge: spreading it on land with minimal treatment; spreading after composting; sequestering it in a landfill; and incinerating it and either using the resulting ash in concrete or some other material or landfilling it. " ..... interesting that the article doesn't mention selling to producers of home gardening materials.

Here is a link that might be useful: disposing of biosolids

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Let's not forget about the prions. That stuff'll make you a sponge brain square pants. Not much does anything about prions.

The fatal flaw with waste water treatment is it is a concentrating process. Take all that awful stuff that people throw down the toilet along with all the other odds and ends that end up in the sewer and then concentrate it.

There's also a confusion of terms. Sewer sludge ain't compost. Even if you compost it, compost won't don't jack to metals and prions.

Garbage in, garbage out

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Our main paper is sf gate, I did not read about it the sf gate. I did hear bout this sludge before I read it here, and I really looked into it carefully to see if I could get any free. Free being the operative word, and I can not, so what the article says is they are giving it to all takers is not correct.

The other article is about Belmont in San Mateo country not San Francisco County. San Mateo does not have good green can program as far as I know San Mateo Starbucks still throw all the grounds in the trash. So, I decided it was a hoax, without more proof of who they were selling it to and why they would add the sludge when they have plant with the green cans program, we have waste treatment plants for the sludge. I believe it flows into the bay, which is bad enough, so the ocean is the real things people should be alarmed about. I do make my own compost and would take it from a questionable source, but still if it was free, I would consider it. Then I would have a way to look into it, but it does not make logically sense for them to add sludge. People would get sick, this is not Mexico, and therefore, we are not immune to sickness, and there would be a scandal and legal action. None of this has happened. We are a very good place for good environmental things.

There are other things the media covers vaguely and does not check sources because they are in the business of making money and not spending time doing investigating reporting. If 60 minutes or something like that looked into it, I would give it some notice.

Well, it looks like there was a program that gave away five pounds of compost on one Saturday in 2007.

http://www.sfenvironment.org/our_programs/topics.html?ssi=3&ti=6

Then in 2008, there was another give-away, where people could get ten gallons.

http://articles.sfgate.com/2008-05-15/bay-area/17152804_1_free-compost-food-waste-golden-gate-disposal

If you look at the city's website, it looks like the compost is given away once a year. Follow this link, and click on the pdf, and it seems as if much of the compost is sued to "top off" the city's landfill.

http://sfwater.org/detail.cfm/MC_ID/14/MSC_ID/127/C_ID/3972/ListID/1

My cynical self thinks that this is one of those efforts to discredit San Francisco's exemplary efforts at reducing waste.

There was a similar brouhaha over the alleged use of sludge on the kitchen garden at the White House

http://obamafoodorama.blogspot.com/search?q=sludge

I think it's so interesting how this theme of "the government is trying to kill us with environmentalism" is taken seriously by anyone.

ericwi wrote:
"I don't understand how the city can responsibly fail to test for pharmaceuticals and certain pesticides. If it is true that cows exposed to this compost later died, then there needs to be an explanation of how that happened."

The dead cows were in Georgia, not San Fran, although I don't disagree with your basic point. Not knowing anything about the GA court case, I wonder what evidence the plaintiffs had that it *was* caused by the sludge that was applied to the food crops.

Well even so, if they gave away some compost in 2008, they don't do it anymore, and that in no way proves there is sludge in the compost they gave away. There is no report of anyone getting sick. They could sue the city, and there would be some kind of lawyers wanting to do this. These guys teased a tiger and one of them was killed at zoo, although he may or may not have actually teased it. The others who were mauled sued and got a lot of money.

Why should our food recycling program be considered to be harmful? It reduces landfill. I fail to see the bad in reduced landfills. We do not have a lot of space in San Francisco.

Here is a link that might be useful: huge pay off in tiger case

I certainly agree with the earlier post by someone who said "we are going to have to come to terms with our waste." If it isn't perfect we're going to have to work on it, but you can't just throw that much organic material away. There is no 'away'.

The fatal flaw with waste water treatment is it is a concentrating process. Take all that awful stuff that people throw down the toilet along with all the other odds and ends that end up in the sewer and then concentrate it.

No wastewater treatment is not simply a concentration process. It is a digestion process, very similar to the composting process, except that it is done in a liquid form. The wastewater treatment process generates a biologicial mass of flora and fauna that consume raw wastes and digests them. The sludge that comes out of wastewater treatment process is what is left over after being consumed, it is digested either anaerobically or aerobically before it is concentrated.

Wastewater treatment plant sludges may have heavy metals in them (as heavy metals are not digested biologically) and they may have pharmaceuticals in them.

Technology exists to remove heavy metals, its a physical/chemical process rather than a biological one. The technology to track and remove pharmaceuticals is still in the development phase.

Sludges that have high concentrations of heavy metals or other contaminants must be landfilled. Class A biosolids (sewage sludge that is allowed to be used by the public) has been tested or treated to meet a minimum standard for heavy metals and other contaminants (except pharmaceuticals, those are still being studied).

The entire reduce/reuse/recycle philosophy is a closed circle. If we are flushing the toilet, then we should be willing to close the circle and reuse our own byproducts.

jopyeweed says, "If we are flushing the toilet, then we should be willing to close the circle and reuse our own byproducts."

In a perfect world, yes. I do "recycle" mine as I am on a septic system...and I am very zealous about what goes down a drain.......city people [also business places] likely are not........... so it is scary.

I am curious about processes to remove heavy metals - would they use resins, or what, and at which point in the treatment plant? Seems it would be difficult due to all the suspended solids and biological material (which would coat any resin type material in short order). Also I would expect the metals to be largely chelated and otherwise tied up in all that biomass, rather than dissovled.

Just curious, as an environmental chemist with an interest in hazardous wastes, so if you have any further info I'd be interested in hearing more.

Nicely explained joepye: I'm guessing what was meant previously by, "concentrating" was the bringing to a central point all of the matter. In a large metro area, the opposite would be interesting, can you say septic systems? Gee, what would happen to all the waste pumped from all those septic tanks? In some areas it is legal to dispose of it directly on ag. lands.

Often times septic tank waste is spread on ag land, but if it can't be, then it is hauled to a treatment plant.

Typically removal of heavy metals is done by manipulating the pH of the water to get the metals to change from dissolved to a solid form. The amount of manipulation required depends upon the metal and the concentration. The resultant precipitate is landfilled as hazardous waste. Its not sludge that is available for public use.

Industrial contributors to a sewer system are required to remove their metals before they can discharge to a public sewer.

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Perhaps I'm cynical. Digested night soil is one thing. All the crud that gets jettisoned into the sewers from drain cleaners to stain removers to drugs to water softener brines ends up in a limited digestive process that we pleasingly call waste water treatment.

It's the stuff that doesn't digest that's scary. It's the stuff that survives and grows in that postmordial soup that's really scary.

I'll stick with the assertion that sewer sludge ain't compost.
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You are absolutely right that sewage sludge isn't compost.

Class A biosolids (sewage sludge that has gone through testing such that it is free of heavy metals and other toxic chemicals) is used as an ingredient in some compost operations.

You are wrong to think that the process at the WWTP is limited in digestion.

I would suggest that people get to know their Wastewater Treatment plant. Take a tour and find out the extent that the water is treated. And find out where your sludge does go? Is it landfilled? Is it land applied? It is sold as biosolids? Wastewater treatment plants are the single largest remover of pollutants from our waterways.

Its the "unknown" that people fear. If you get familiar with it and understand it, then you can make a fair decision on whether to use the resultant sludge.

Many treatment plants cannot offer their sludge to the public. But most small towns with limited industrial users have thorough digestion and clean sludge. Most WWTP sludges are applied to agriculture fields.

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I must be cynical.

Our county was shipping the biosolids to another county to be land applied. That other county decided they didn't like the imports. Something about smells and metals. Go figure. Now it's land applied cover to a county landfill less than 10 miles from here. Some locals are worried. Dry country around here. The wind kicks up a lot of dust. Care to live downwind from that?

I don't trust the gummint to tell me everything. Then there's the shear volume. Similar to the problem with ballistic missile defense - how much leakage can you take? We are dealing with a lot effluent from a lot of sources. The only thing that keeps the local gummints in check is the state telling them what they can't dump in the water ways. So if it isn't going in the waterways what remains is even more concentrated.

A long long time ago I got to visit the Hyperian water treatment facilities in LA. At the time its discharge was the 6th largest river in Calley forn ya.

I remember my Dad used to operate a plating facility for circuit boards. He was complaining that the OSHA people were giving him a hard time about the amount of zinc. His complaint was there was more zinc in toothpaste.

So regulate the industrial contributers all you like but I think the household contributions to the waste stream alone is enough to worry about. Household contributions are unrestricted and I expect the worse knowing that there are still people out there that will dump their used motor oil down the storm drains.

I get the contents from some of my neighbors curb side garden waste bins from time to time. I'm getting tired of spending a half hour or so for each bin cleaning out the garbage they throw in there.

Science uses pigs for experimentation because of their anatomical similarities to humans. Cannibals call human flesh to be eaten 'Long Pig'. Must have something to do with the taste. It's hard sometimes, sometimes really hard, to not think of people as pigs.

To sense
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joepyeweed is accurate in his statements about how the systems work. With regard to metals, some of the load *is* going to be captured in the biosolids, it is not all in the clarified effluent to be precipitated in a nice neat package. If this were not the case there would be no need for biosolids standards for metals. I'm sure you know that, I'm just pointing it out for others. I do agree 100% that people should understand their waste treatment systems. I've thought for a long time that anyone with curbside trash service should have to tour the landfill.

In addition, not everything organic (i.e. not metals) does break down 100% in the WWTP. Hence the interest in drugs and plasticizers and surfactants in the waterways. rott makes a very good point about the household contributions too.

rott, I assume the spraying on the landfill was done as part of the daily cover? In which case it would be buried and not available for dust-making. Or do you mean sprayed on the cap after a portion of the landfill was closed to support grass? Even in that case I would not be too worried about that amount 10 miles away. Not to minimize the problem, we do need to run things cleaner, and this sludge thing is a poster child for that.

I didn't even bother to reply to rott's post because his problem is trust.

He doesn't trust "government"; but who is the government?

It must be hard to go through life and not trust anyone. We must realize the guy working at the WWTP is doing a job just like we all do our jobs. I know lots of people in the waste industry who take pride in safely cleaning up the environment where they live.

If its about trust, then facts aren't going to make any difference.

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A certain amount of skepticism is healthy I think. Just because I saw it on the internet doesn't make it true.

The gummint is made up of people. Like the people in corporations. Like the people that sell you used cars. Seems to me that the people who go running to the gummint to solve all their problems are very often the ones who like to bash corporations for sport. Name your poison.

I've got a bridge for sale if you're interested.

To sense

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I was doing some reading and came across an article at Mother Jones about the lead in the White House garden flap last summer. The article mentions the Alabama cow kill case, and that it happened in *1979*. That was a LONG time ago - pre-RCRA and pre-Biosolids Rule.

However, MJ also stated the following:

>In May 2007, the EPA learned that sludge had contaminated as many as 5,000 acres of grazing land [in Lawrence County, Alabama] with perfluorooctanoic acid (PFOA), a probable carcinogen used in Teflon. The chemical was traced back to a local manufacturer that had dumped contaminated wastewater straight into the sewer. The case prompted the EPA to issue its first-ever advisory on PFOA in drinking water, but it did not ban the dumping of the chemical into sewers or require sludge to be tested for it. Even though the exceedingly high PFOA concentrations in the Lawrence County fields could pose a health threat to animals or humans, as of press time, the Department of Agriculture hadn't tested local cattle for the chemical.

We still have some challenges ahead of us.

If you really want "free" biosolids why not just go the safe and easy route and trade your toilet for a bucket? Seriously. Would you actually spread municipal sludge on your veggie bed? I wouldn't. If I'm gonna put sh-t in my garden I at least want to know the source. I wouldn't put my neighbor's pee in my compost any more than I want everyone else's chemicals and drugs in my garden.

It takes about 2 years to safely compost your own waste. Just add a lot of browns and keep it separate from your normal compost. I haven't done it yet myself, but my "low-water" toilet does not often like to do its job, so I've been tempted. I am a vegetarian, so my poo may be safer than others', but I'm not sure about that.

>Would you actually spread municipal sludge on your veggie bed?

No. I might consider it for my lawn if it was available in my city, as a solid compost product.

>I wouldn't put my neighbor's pee in my compost any more than I want everyone else's chemicals and drugs in my garden.

I do put my own pee around the place, when the opportunity presents itself. :-] There's an extensive thread on that around here somewhere...

"I do put my own pee around the place, when the opportunity presents itself. :-] "

Me too ;) In the compost pile, but only my own.

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What goes into the sewer?

In the kitchen I'm wondering what is in that jet dry stuff for the dishwasher.

In the laundry I'm wondering what's in fabric softener.

In the bathroom I'm wondering what in all those medicines.

How many nutballs out there throw in all kinds of stuff into the toilets and drains that collect into 50 year old waste water treatment plants made for municipalities half their current size?

Testing? Test for what? If you can't be sure what's in there, how can you test for it?

I suppose you can always get your money back when the biosolids don't work for you.

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>Testing? Test for what? If you can't be sure what's in there, how can you test for it?

Well, we do have some idea. There's a whole field of study of emerging contaminants. The next generation after the classic ones (DDT, metals, etc.) that were first regulated on the basis that they would flat out kill off wildlife. Now we're looking at endocrine disruption and other non-fatal effects of drugs, surfactants, plasticizers. The list is huge, and many different analytical methods would be required for any one sample to look at them all. Then, what do you compare the results to? Detectability does not equal toxicity. We have a long way to go, but we're climbing, I think.

this subject been around here and there before.

where i live they compost all compostable waste they chip up old furniture and lanscaping timber/logs you name it, it gets added to garden and tree lopping waste, along with up to medium grade industrial liquid waste and the humus from the sewerage treatment works.

over here they sell it to gardeners sometimes give it away, it goes to blenders of all sorts of products ie.,. potting mix, soil improvers, etc.,. and gets sold over the counter. the heaps they compost it in and mix the liquid waste into obviously get hot, how hot dunno?

the stuff that goes to potting mix blenders and baggers of soil improvers is likley screened but that from the dump sites can have all sorts of stuff in it notable pieces of plastics that get mixed into the stream early on. it is in all over the counter product.

to use or not to use, i follow the regime so long as you are fully educated into what something may contain and that product is all that is available then what to do? use it i would say but maybe sparingly. we all use potting mixes so very likley we are all using the stuff in someway anyway?

if gardeners don't use it they will put more of it onto conventional farms that is the thrust so maybe down track it will no longer be available to gardeners.

a vexing question? is this the lesser of 2 evils?

len

Here is a link that might be useful: lens garden page

It may indeed be the lesser of evils. The elegant solution, of course, is for all of us to use less toxic chemicals and products that contain toxic chemicals. For example, most people use way too much soap and detergent than is really needed to get the job done. Some of those surfactants go through the treatment plant undigested, and if they reach high enough concentrations in the receiving waterways, endocrine disruption can increase. Word to the wise. Reduce comes before reuse and recycle.