Hey everyone, it is my first time posting here and I come to you with a ridiculous situation.
I got a job at a pig farm, where tons and tons of manure is produced. After pressing the slurry and sending the liquids to a biodigestor, I am left with the solids and my job is to compost them. The owners didn't plan to make compost at all, but environmental regulations force them to do something with the pig slurry.
They bought a Kohshin composting machine from Japan for quite some money and now they want to sell pig manure compost to recover their investment. In past years they made their workers compost it manually in different tests and the results where kinda promising.
Now, with the machine, what comes out of the piles is toxic:
- Organic Matter (g/kg) – 916.4 g/kg
- Ash (g/kg) – 83.6 g/kg
- Total Carbon (g/kg) – 531.53 g/kg
- Carbon/Nitrogen Ratio (C/N) – 2.32
- Total Nitrogen (g/kg) – 229.11 g/kg
- Phosphorus (g/kg) – 2.47 g/kg
- Potassium (g/kg) – <LOQ
- Sodium (g/kg) – 1.14 g/kg
- Calcium (g/kg) – 19.91 g/kg
- Magnesium (g/kg) – 1.95 g/kg
- N-NO₃ (mg/kg) – 62.00 mg/kg
- Chlorides (mg/kg) – 2038.22 mg/kg
- Sulfates (g/kg) – 9.49 g/kg
- Copper (mg/kg) – 263.30 mg/kg
- Iron (mg/kg) – 2124.00 mg/kg
- Zinc (mg/kg) – 505.30 mg/kg
- Manganese (mg/kg) – 127.80 mg/kg
- Boron (mg/kg) – 18.09 mg/kg
- pH (1:10 Mixture) – 5.8
- Carbonates (1=low, 3=high) (meq/kg) – ND
- Electrical Conductivity (1:10 Extract) (dS/m) – 5.49 dS/m
I know what the problems are: 1. Lack of carbon-rich material, 2. Turning and aireating the piles daily (because "they want to make use of their new toy"), 3. Inefficient humidity control, 4. Avoiding to let the compost rest for 30 or so days, 5. Lack of a lixiviation system, 6. Not being in control of the pigs diet (we are wean-to-finish).
Because of all these errors, when the piles come out of the tracks, THEY ARE STILL BURNING HOT, and thats what they want me to sell to the public.
They won't listen to reason because their hand-turned compost got better results but I know that the C/N ratio of those composts were 8:1 and 13:1 because they lost all the nitrogen, which happened because they don't add a carbon rich material.
IMO, the only way to use this would be by selling it to composting companies so they can use it as a brown material. Worms would likely suffer in these substrate unless is combined with other material and so would Black Soldier Flies.
This whole thing has me depressed and anxious as I need these job to pay for my car, bills and master's degree, but if we can't start over with new trials or reuse the concentrated manure that we have to make real compost, then I will be most likely fired for not being able to sell poison.
What do you guys think?
by Fluid_Foot_1068
19 Comments
Look into turning it into biochar
Consider this a part of your education.
I think your brave to tell your story!
Hope you find a solution!
Uhh. This isn’t gonna go the way you think.
That stuff is fine. It’s a bioactive fertilizer with 2.9% nitrogen and would be great for growing trees or commodity feed crops. Contact local arborists, tree farms, and people who do grains/alfalfa/hay.
Hope you didn’t show your ass at work.
Low C/N ratio (2.3)
Add carbon (sawdust, straw, leaves, etc.)
Compost still hot
Cure for 4–6 weeks
High salinity (EC 5.49)
Leach or dilute with carbon-rich materials
Toxic to plants
Blend, test, rest – do not sell immature
Pathogens possible
Ensure temps reached 55–65°C during composting
What other industries are nearby? Are there other waste products available that could balance out the mix?
From experience, I’ve used hot compost, from pig manure and other materials, and everything has been fine.
You realize that it’s going to continue to break down and stabilize right?
Could this be sold as an amendment or additive?
Much appreciate the education, detail, and sincerity.
I’d buy that. Are the toxins in the room with you now?
Can’t you just mix it with wood chips.
I read toxic and expected stuff like lead paint or benzene or whatever.
You just need more carbon rich compost materials. Call up all your local tree companies and see who needs to get rid of wood chips or mulch. They will often give them to you just to avoid the trip to the dump if they are in the area. If you get a good relationship with a busy company it might be a cheap solution for both of you.
I would be concerned about the heavy metals content that is not shown in your numbers.
Ever hear of Milorganite? Milwaukee organic fertilizer.
It’s the cheapest fertilizer you can buy at Home Depot, assuming they still sell it. It’s 100% organic.
As in, it’s 100% composted organic human waste. Still organic, and LOADED with heavy metals.
This material has been used by decades by the National Park Service as ordered by the government, because if they don’t spread that around, it’s classified as toxic waste. Exceptions were put in the law to be able to use it on ornamental lawns.
So, when Michelle Obama wants to make an organic garden at the White House, she wanted to do it on a lawn that had been using Milorganite for *decades*.
Heavy metal contamination was off the charts when they tested the soil. They had to dig out tons of White House lawn dirt and ship in good, uncontaminated topsoil so that she could have her organic garden at the White House.
So yeah, composting mammal waste from highly-concentrated sources can concentrate all of the bad things, and it makes it into the compost.
Humans consume different foods, take lots of prescription drugs and have exposure to other things that can affect what goes in their waste, but pigs also have similar things, drugs they are given, antibiotics, and feed that may contain metals in low concentration, but would be concentrated through the waste treatment process.
If your boss gave you those numbers, he may have omitted the heavy metals, or the testing company just doesn’t test for it because they don’t want to give people bad news.
If it’s as bad as you say, surely no one would even buy it? Are you being told to lie about its composition as well? If so, you should report your employer to the appropriate authorities.
As bad as you think this is, it is still much better than biosolids made from sewage because it doesn’t have all the weird stuff that people flush down toilets.
Just be honest about what it is when you sell to a customer and you have done your duty. You warn them about high nitrogen, salinity, etc and they should adjust for that. Show them the lab results if you want.
Do you have heavy metals testing available too? That’s probably the easiest way to get a regulatory body to jump in and save your job.
“I started selling it and they told me to stop…” And then you can even suggest the fix and show off to your bosses when you get an agency off their dick.
Edit: this presumes a lot though
I worked somewhere similar to this where I was permit holder. As long as you’re meeting your required Process to Further Reduce Pathogens (if even required); this should be fine if used properly. We would make an extremely high N, fairly wet compost that was still very active when sold – farmers loved it because they were amending at 2-5 tons/acre so the high N and organic matter was cut enough by application and tilling that they never saw issues with volatility. If you’re around other ag – look for some of the waste materials that hog feedlots can’t take (soybean stem waste, corn fodder, etc.) and see if you can get it for way better cost than sawdust (which is always expensive). We used to let tree guys dump for free. Good luck!
Seems like a perfect thing to mix with raw biochar. Massive carbon source, can tie up heavy metals, etc. But if they don’t want to pay for sawdust, I doubt they want to pay for that.