As cities expand and our population continues to increase, we are continuously faced with the problem of what to do with our waste. Human waste is an especially tough problem. We currently use large municipal treatment centers to filter it out of wastewater and return what is then considered clean water to streams and rivers. But what about the leftovers?
When human fecal matter used for fertilizer it is called municipal sewage sludge or biosolids. A problem faced with using sludge is that it is not simply fecal matter. Because it is collected from a treatment center, which often filters waste for large areas, there are also contaminants from hospitals, industry, institutions, businesses, landfills and households who discharge into sewers. Some of these chemicals persist and can bioaccumulate in us.
Europe also currently uses sludge. However it is strictly regulated and only allowed in certain cases if the sludge in question meets certain criteria. The concentration of pollutants must not exceed a certain level.
The U.S. also has policies regulating the use of sludge. The EPA has also done studies that show the risk for humans is very low, if all criteria for the sludge are met.
Alternatives to using sludge on agriculture are to burn it or to bury it in a landfill. With both of these pollutants can be released and we can indirectly ingest them, but the incidence would be lower. I believe most would say that dispersing pollutants is better than directly ingesting them. Also, by placing sludge into a landfill, we run the risk of it leaking out and polluting groundwater or other waterways.
So the question is which is worse. Should we risk using sludge as a fertilizer when it might contain contaminants that could be passed onto us through the food that it helps to grow? I don't think so. The possible health risks are too great. Even though studies have shown that if used correctly it is not toxic, I think that alternate ways of disposing of sludge are better. It is unlikely that a person buying food from a grocery store would know that a product was grown using sludge. I am sure that if they did, they would be less likely to buy it because of the chance of contaminants. Overall, disposal of waste is a continuing problem but I do not think using sludge as fertilizer for commercial agriculture is a good idea.
Image from:
http://www.veoliawater.com/library/fr/repository/37D8vA2yGdTK35O-main.jpeg
http://wpcontent.answers.com/wikipedia/commons/thumb/8/84/Biosolid.pumpkin.row.jpg/220px-Biosolid.pumpkin.row.jpg
Like you said, if all criteria is met, then the harm coming from sludge is very low, so I do not really seem it posing a problem when being used as a fertilizer. It would help out the fact that we already have way to much wastes in landfills and sewer disposals. Of course, everything should be very well regulated, and sludge that could contain potentially higher contaminants such as from hospitals, should not be used. Otherwise, i'm all for the sludge.
ReplyDeleteJacquelyn Wright
The problem of where to store or use biosolids/sludge is a growing topic. I have to agree that I do not like the idea of possibly eating produce that has been grown in human waste, let alone possible toxic chemicals.
ReplyDeleteIn 2001 the EPA conducted a survey to obtain updated national estimates of dioxins and dioxin-like compounds in sewage sludge managed by land application. Results from this survey helped EPA conclude that the incremental risk from exposure to dioxins in land-applied biosolids is below levels of concern. Also, the EPA has begun assessing the nine pollutants identified from the 2003 biennial review as needing updated concentration information and molybdenum to determine whether additional action may be necessary.
This seems as if the EPA is on top of managing and monitoring these chemicals, although this is the newest information from the EPA website itself explaining biosolids and sewage sludge issues. In my opinion, a follow-up needs to be done, a new survey conducted, and new regulations need enactment for these problem chemicals in biosolids.
I agree with both of you that it does seem safe, especially since the EPA is monitoring it so closely. I just worry that someone will abuse this system someday because that seems to happen with a lot of other systems. I think that if there was a program to inform shoppers of what farming methods were used to grow their crops sludge would be a better idea. It just bothers me that people don't know that their food could have been grown in fertilizer that could possibly have harmful chemicals in it. And in the meantime, until the EPA is totally sure about sludge, I think there are other methods, like burning, that can be used. If I knew that my food had been grown with sludge, I would probably buy a different product just to avoid the risks all together so I wouldn't have to worry about it, and I would definitely wash my vegetables off with soap!
ReplyDeleteI'm sorry but just because it is supposedly safe doesn't mean that using sludge as fertilizer is a feasible option. Most sane people would never in a million years buy things that have been grown in human waste. If there are even minimal risks, then every product would most likely be required to carry some sort of label that it had been fertilized with sludge - an instant deal breaker for the majority of Americans (or at least those who don't like eating their own waste)...
ReplyDeleteSewage sludge "biosolids" contain hazardous industrial chemicals, drugs, radioactivity, landfill and superfund leachates and virulent antibiotic resistant microbes.
ReplyDeleteClass A sludge "compost" is promoted as being virtually pathogen-free". It is not. All sludge - both Class B AND CLASS A - may contain infectious human and animal prions. In a September 2008 report, the US EPA lists prions as one of the emerging contaminants of concern in sludge biosolids. http://www.epa.gov/waterscience/strategy/compendium.pdf
Prion researcher Dr. Joel Pedersen, Univ. of Wisconsin:
" Our results suggest that if prions were to enter municipal wastewater treatment systems, most of the agent would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in
treated biosolids. Land application of biosolids containing prions could represent a route for their unintentional introduction into the environment. Our results argue for excluding inputs of prions to municipal wastewater treatment."
"Prions could end up in wastewater treatment plants via slaughterhouse drains, hunted game cleaned in a sink, or humans with vCJD shedding prions in their urine or faeces, Pedersen says"
Recently, researchers at UC Santa Cruz announced that Alzheimer's Disease (AD) is a prion disease. Nobel Prize winner (for his prion research) Dr. Stanley Prusiner, UCSF, recently wrote that Parkinson's Disease may also be a prion disease (over 1 million US victims).
Thus, 6.3 million US Alzheimer's and Parkinson's victims may be shedding infectious prions in their urine and feces to public sewers. The wastewater treatment process does NOT inactivate prions, They are concentrated in the sludge. http://sludgevictims.com/pathogens/prion.html
Sludge topdressed on grazing lands, hay fields and dairy pastures poses risk of prion infections of wildlife and livestock. Class A sludge "biosolids" spread in home gardens poses prion risks to humans, including "eat dirt' children, and family pets.
----- Original Message -----
From: Helane Shields
To: a
Sent: Friday, April 23, 2010 12:35 PM
Subject: LETTER TO EDITOR - go back and check EPA EMERGING CONTAMINANTS PRIONS CLASS A - NOT STERILE OR PATHOGEN FREE - 5.3 MILLION AD VICTIMS.- posted
http://www.sfgate.com/cgi-bin/blogs/kalw/detail?entry_id=61960&o=1&rv=1272040397906>a=commentslistpos#commentslistpos
In September 2008 the US EPA issued a report listing EMERGING CONTAMINANTS OF CONCERN IN SLUDGE "BIOSOLIDS" AND WASTEWATER. Included were endocrine disrupters, drugs and personal care products, nanomaterials, flouorinated compounds, and PRIONS.
None of those substances are monitored, tested or regulated.
San Francisco promotes its Class A sludge biosolids as being pathogen free. It is not, because PRIONS ARE PATHOGENS. Univ. of Wisconsin researchers found infectious human and animal prions survive up to 3 years in soil and become 680 times more infectious when bound to dirt. Human prions are 100,000 times more difficult to inactiavate than animal prions. An infectious dose is measured in molecules.
Recently, researchers at UC Santa Cruz announced that Alzheimer's Disease (AD) is a prion disease.
Thus, 5.3 million US Alzheimer's victims may be shedding infectious prions in their urine and feces to public sewers. The wastewater treatment process does NOT inactivate prions, They are concentrated in the sludge. http://sludgevictims.com/pathogens/prion.html
Bay area sewage plants should focus on the plan to use their sludge biosolids as a renewable resource to generate power and energy, and keep it off agricultural land and out of home and school gardens.