Just found this.

When San Francisco, one of the greenest cities in America, offered its residents free compost, many were excited to take it. Few of the gardeners who lined up to receive the free compost at events like last September's Big Blue Bucket Eco-Fair suspected that the 20 tons of free bags labeled "organic biosolids compost" actually contained sewage sludge from nine California counties. On Thursday, March 4, angry San Franciscans returned the toxic sludge to the city, dumping it at Mayor Gavin Newsom's office in protest.

Sewage sludge is the end product of the treatment process for any human waste, hospital waste, industrial waste and -- in San Francisco -- stormwater that goes down the drain. The end goal is treated water (called effluent), which San Francisco dumps into the Pacific Ocean and San Francisco Bay. But the impurities and toxins removed from the water do not go away. With the water removed, the remaining byproduct is a highly concentrated toxic sludge containing anything that went down the drain but did not break down during the treatment process. That usually includes a number of heavy metals, polycyclic aromatic hydrocarbons, pharmaceuticals, steroids, flame-retardants, bacteria (including antibiotic-resistant bacteria), fungi, parasites and viruses.

The EPA only requires treatment plants to kill off any fecal coliforms in the sludge and ensure that nine heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, molybdenum, selenium and zinc) are not present in unacceptable levels. But that only cleans up a tiny fraction of the harmful substances present in the sludge. A recent EPA study of 84 sludge samples from around the country found 27 metals, three pharmaceuticals (Ciprofloxacin, Diphenhydramine and Triclocarban), four anions (nitrates/nitrites, fluoride and water-extractable phosphorus), three steroids (Campesterol, Cholestanol and Coprostanol), and a number of toxic flame-retardants in nearly every single sample tested. Many of the other contaminants tested for showed up in a high percentage of samples as well.

The land application of sewage sludge is actually a national issue, not merely an issue limited to San Francisco or even California. It can be traced back to the Clean Water Act and the subsequent outlawing of dumping sewage sludge into the ocean. The Clean Water Act of 1972 required sewage plants to remove at least 85 percent of pollutants in the waste they received before discharging the resulting effluent. Waste treatment reform advocate Abby Rockefeller points out the irony that the more successful a plant is in removing impurities and toxins from wastewater, the more concentrated and toxic the resulting sludge.

Other options to dispose of the sludge exist, such as dumping into landfills, incineration (releasing pollutants into the air), or gasification to generate methanol for energy (the most environmentally sound and most expensive option), but land application is the cheapest. That is -- it's the cheapest to the dumper, but perhaps not to the dumpee. One year after sludge was spread on an adjacent farm, the cows began to die on the Washington dairy farm of Linda and Raymond Zander. Tests revealed heavy metals in the soil where the sludge was applied and in two neighborhood wells. The casualties were not limited to the cows; Raymond Zander suffered from nickel poisoning and 16 neighboring families reported a range of health problems they believe are linked to the sludge.

So where does this leave San Francisco? According to the EPA, about half of all sewage sludge is applied to farmland as fertilizer. As seen in the McElmurray case, even when sludge is limited to use on fields growing animal feed, the toxins in it can still find their way to the human food supply. Also, Class A biosolids are approved for unrestricted use, meaning they can be applied to farms growing food for humans (although they cannot be applied on land where organic food is grown). EPA expert Hugh Kaufman warns that government regulation for Class A biosolids ignores 99 percent of the pollutants found in it.

In San Francisco, the sludge hit the fan because the city had the audacity to label sludge as "organic" and give it away to home gardeners and even school gardens. The city's actions are outrageous, but they serve as a wake-up call that the entire nation regularly consumes foods grown on fields fertilized with sludge. The so-called beneficial use of our sewage sludge is actually the distribution of sludge into our land, our water and our bodies.

This post was edited by ernie85017 on Thu, Mar 6, 14 at 14:34

he EPA's 2009 Targeted National Sewage Sludge Survey concluded that all sewage sludge contains toxic and hazardous materials, including large numbers of endocrine disruptors. The Targeted National Sewage Sludge Survey results are described in two EPA reports published in 2009. EPA found that dozens of hazardous materials, not regulated and not required to be tested for, have been documented in each and every one of the sludge samples EPA took around the USA. [1] Hundreds of communities across the U.S. sell sludge products that are renamed biosolids and sold or given away as "organic fertilizer."

I think people sometimes go a little overboard on the 'toxic' thing, and I say that as a gummint regulator of hazardous substances. Below is a link to EPA's page on the Biosolids Rule. Also I would recommend searching this forum using the keyword "sludge" to find some good comments from others more knowledgeable than me about the rules.

For me the big question is how important the quantities are that are found in the stuff. Given enough lab equipment, I can find dioxin in your chocolate milk, but it doesn't mean it's a risk. When people wave around research studies that show umpty-ump chemicals were detected, they are overinterpreting the studies, because such a study does not measure risk, but only seeks to identify contaminants and the levels present. It is Step 1 in a multi-step risk assessment.

All that said, due to the uncertainty about the risks, and the availability of other compost, I personally would not choose to use it on edibles.

Here is a link that might be useful: EPA Biosolids Page

"I think people sometimes go a little overboard on the 'toxic' thing"

Ditto Tox, I work for a sewer company, so I know a little bit.

All sludge, water, and other byproducts are closely monitored and tested in high tech labs. And there are sophisticated monitoring systems that catch bad things coming through.

Someone recently dumped PCB's into the system. It was detected immediately and diverted. All land applications stopped from all of the plants even though there were no PCB's at most of the plants.

We have spent millions of extra $ processing ALL of our sewage to be sure that we aren't allowing someones D*** A** dumping to be released into other places.

I feel safe that I could use our sludge on vegetables, but I wouldn't because of the EWWWW factor!

No, humans are the moist diseased and poisoned creatures in the world now - this won't help.

"humans are the moist diseased and poisoned creatures in the world now"

Ummm...okay, then...uh...hmmm.

I know a lot of fish, bird, lizard, and plant species that would like to have a word with you on that subject. ...and there's the whole aspect of what's being sold as human sludge to the general public is already well composted (with much more regulation and care than even most every plant waste composting facility).

To get back on subject...

The biggest downside to using sewage sludge for anything but lawns and trees/shrubs...aka, food crops...is using them in constant application as an amendment for years on end.

The accumulation of metals via constant application can occasionally cause some problems with a lot of annual plants sensitive to them. A lot of grasses and trees/shrubs can handle it fine, but growing veggies through seedling/youth/adult/fruiting/decline has various levels of sensitivities to metal buildup in the soil.

It's a nice source for a lot of things, but it's not something I'd use as an "every season/year" compost amendment to a veggie garden.

Most sludge that is used on cropland is NOT sterilized and is still filled with bacteria and viruses and hookworm eggs, etc. (Class B sludge).

And in SC, I think I remember that PCBs were found on some farms where sludge had been used.

It's a trade-off. I've used it on some ornamentals at home, but not around fruit trees or in the garden. If I were growing ornamental palms, say, in containers, then I would be using a lot of it.

Your home gardener end-user consumer isn't going to be able to get the more "raw" versions of sludge, though...they have to deal with the highly composted stuff (thankfully).

When you're dealing with the stuff that isn't available to the general public at large you're moving into realms of regulation regarding storage and application rather than the stuff that people can just load up in the back of an open truck bed and take home.

ernie needs to post the source of his information so we can know if it was published last week or 50 years ago.
As of now using sewage sludge, biosoilds, in your home garden is not recommended because of the potential of diseases, but then the use of animal manures is not recommended for the same reasons.

They were recent publications. I was researching so I could make an informed decision. Sorry, don't have the pages.

The "SF compost protest" thing happened in 2009, btw...if you can call a handful of people a protest.

They had been doing it since 2007 and halted the public giveaway in 2010 much to the dismay of many that used it and to the joy of Northern California commercial farmers who now enjoy more access to it.

Certain animals are more sensitive to pollution. But you'd not want to (knowingly) eat poisoned animals / plants every day just because they're cooked but contained certain nutrients. Even though regulations say this is good for us since most food is like that for humans and domestic animals. The big agribusinesses don't have a good record of treating land well. If it was pure human waste it'd be concerning due to the drugs that everyone is taking. And the raw sludge would end up back on everyone's plates even if not in the personal garden.