Saturday, February 11, 2012

Waste Not

Last autumn I was on a garlic seed production research tear. I came across a company in china called Pretty Garlic. Log onto their website to read the mythical origins of pretty garlic -something about a sick girl saved by garlic. In reading their how-to-grow garlic page, I was a little surprised by the frank use of the term "human wastes" as supplement to growing garlic. Right click this screen-capture image so you can read it in full. After reading this, it was easy to see how American farming has been consumed by public relations, because I honestly don't think conventional farms are operating much different here than they are in China.

In the U.S., we come up with all kinds of euphemisms for human waste, so why wouldn't we do the same when talking about sewage-based agricultural products. I believe Biosolid is the preferred term, apparently generated by a focus group or PR campaign some years back to improve the image of sewage sludge.  See the EPA website for their bland assessment of applied sewage sludge products. The FAQ that most concerns me is this one:

11) Are there regulations for the land application of biosolids?
  The federal biosolids rule is contained in 40 CFR Part 503. Biosolids that are to be land applied must meet these strict regulations and quality standards. The Part 503 rule governing the use and disposal of biosolids contain numerical limits, for metals in biosolids, pathogen reduction standards, site restriction, crop harvesting restrictions and monitoring, record keeping and reporting requirements for land applied biosolids as well as similar requirements for biosolids that are surface disposed or incinerated. Most recently, standards have been proposed to include requirements in the Part 503 Rule that limit the concentration of dioxin and dioxin like compounds in biosolids to ensure safe land application. (Italics mine)
I'm not interested in using biosolids or sewage sludge-based compost on my garden mainly for the questions that the above answer dredges up. Questions like: how come we can spread dioxins, currently, on agricultural fields? There are limits for heavy metals contamination in agricultural fields, so wouldn't the annual application of cadmium, for instance, increase the load of contamination year to year? 

Someone can make the argument that it is completely unknown what quantities of heavy metals in garden or agricultural soils it actually takes before human health is affected. I concur. We have no idea. Lead, for instance, is limited to 400 ppm in NYS restricted residential soils (not intended for gardening), but Minnesota limits it at 100 ppm, while background levels appear near 20 ppm. Try to find scientifically studied limits for Cadmium, chromium, aluminum, zinc, molybdenum, mercury, etc., etc.

Last summer I smelled something near awful around my father-in-law's garden. I didn't know what it was until I later spotted him spreading grains of something all around his flowers and shrubs. In detective mode, I searched out the bag he had used and opened it up for a whiff. Yup. Milorganite. Something I had heard of, but given little thought to. Retail-branded sewage sludge from Milwaukee, Wisconsin. 
 My problem with municipal treatment is its catchall process. In other words, anything your neighbor drops down his sink, toilet, or catch basin, finds its way into your treatment plant. Are they really capable of eliminating all the contaminants from that pool? What about industrial wastes flushed into the system?

We do have to do something with all the waste we generate. But what? In the mid-19th century, after several outbreaks of cholera and other infectious diseases, Sir Edwin Chadwick proposed a sewage network for London that included the collection of human wastes for dispersal on farm fields, but this part of his plan was unfeasible and the sewage ended up in the Thames until sewage treatment plants became viable.

In our own time, sewage treatment based products are spread onto farm fields. Some municipalities pay farmers to take their waste. Some municipalities pay private companies (like Synagro) to collect and dispose of the sludge in various ways. Some municipalities create product, like Milorganite, for sale to the public. No matter which way you do it, Chadwick's original idea has come to pass, but a lot more goes into our sewers now than in his day.

What do you think? Have you already spread 'biosolids' onto your garden, knowingly or not?

The San Francisco Public Utilities Commission had in past years delivered free 'organic compost' to any citizen of the city who wanted it. The scandal that ensued was called Chez Sludge because of the involvement, however indirect, of Chez Panisse's Alice Waters, famous for her promotion of organically-raised produce.

In another more horrifying scandal, the backyards of poor black families in Baltimore were covered in sewage sludge in order, said those responsible, to protect the children from seriously high lead levels in their backyard soils. I believe the term for this theory is "Sludge Magic," promoted by a former EPA scientist and USDA official (Read this document). In short - the theory states that once soil contaminated with dangerous levels of lead is mixed with 'highly processed' sewage sludge it is safe for children to ingest. Really? By the way, excuse the low-rent links, as there was no media attention to this story.

If you asked people whether or not they would be inclined to compost their own feces and urine to spread on their vegetable garden, I think many would say they would rather not. Yet, somehow, once it becomes a product, it is then acceptable. Maybe it has something to do with what I call the bologna effect. If you had to make the bologna yourself, you might just not want to eat it, but since it comes in that nice roll at the supermarket, it's not so bad with mustard on bread.


  1. Austin offers Dillo Dirt which is a combination of yard waste collected by the city and sewage. The idea of poo and pee being in compost doesn't bother me, but I have the same problem as you with the heavy metals and other contaminants in sewage. That's the part that confuses me and rarely seems to be addressed by the people who warn against using composted sewage solids. Thank you for finally pointing it out!

  2. I kind of agree. Sometimes recycling can be a scary thing. Reading a bit about how industrial waste ends up being converted to soil amendments or fertilizers sometimes feels like you're reading a horror novel. There are a few states in recent years that are requiring the reporting of heavy metals and other information in fertilizer products (maybe Washington, Oregon, etc) (You can at least look up the product you are buying or search for an amendment with the lowest levels) Sorry to hear that your soil test came back with bad results. Was it at the beach or the garlic farm?

  3. Beach. :-(
    Not the worst, but still disappointing.
    I would rather compost my own than buy the bagged stuff. I think I bought sludge compost from a home depot in New Mexico 15 years ago. It was so cheap and then I read about Texas made sludge compost. The product was from Texas, was dense and wet, and was funky in odor. I now know what to look for and look for ingredients. I have no problem with the crap. In fact, you'll read that the sludge I not actually the crap, but the dead carcasses of all the organisms that ate the organic matter. The poisons accumulating worries me more. Although not enough study of the pathogens has taken place. There are also different classes of bio solid. You might accept type a but not type b. how would you know?