Composting A Dead Horse: The ProcessBy Jeffrey Rolo
In our previous article regarding composting a dead horse we learned how to create a horse compost pile, from selecting an appropriate site to which materials should be used. Now we're ready to “activate” the pile and monitor it throughout the composting process.
Just Add Water
Once your compost pile has been formed, you'll need to wet it down. The moisture levels throughout the composting process must fall within a 40-60 percent wet weight ratio. Initiating the pile with a 50% ratio is a safe starting point. Let's say the horse carcass weighs approximately 1100 pounds. At a 50% wet weight ratio, you would be looking to add 550 pounds of water to the compost pile, or approximately 66 gallons.
One reason I don't recommend composting a dead horse for beginners is that although maintaining proper moisture levels is critical to ensuring a successful compost, it will require some trial and error until you get the feel for it. The weight of a carcass can vary the wet weight ratios, plus moisture added through natural means such as morning dew, rainfall, etc. must be taken into account when determining how much additional water is required by you periodically.
As long as you keep the pile somewhere within the 40-60 percent ballpark, you should be fine. There is some wiggle-room, just don't let your pile dry out or become too wet.
Compost Temperatures Are Key
Biological processes such as composting are tricky, and unless you're a scientist by trade, chances are you'd rather not need to worry about things such as proper pH levels, C:N ratios, or pathogens (bacteria and viruses). The bad news is that you don't have a choice if you wish to compost a horse carcass; the good news is that you need not break out a chemistry set to know if everything is proceeding properly. The compost pile's temperature will tell you all you need to know.
It will take a few days for a compost pile to heat up, but once a few days pass the pile should always contain a minimum temperature of 130 degrees Fahrenheit. 130 degrees is the absolute minimum; the sweet spot for a compost pile is 140 degrees. Temperatures can safely go up to as high as 160 degrees, but if it exceeds 170 degrees you run the risk of spontaneous combustion, so remove and cool the materials. It will be uncommon for a pile to exceed 160 degrees, but it is a potential problem to be aware of.
On the flip side, it's far more common for a pile to have difficulty achieving the 130 degree minimum. If your pile is having a problem warming up to the necessary temperatures, it's likely in an anaerobic state, which is characterized by strong odors as well as black sludge escaping from the bottom of the pile. Two common culprits of an anaerobic pile are a lack of nitrogen (fertilizer can help combat this) as well as too much moisture.
If after a few days your compost pile doesn't achieve the necessary internal temperatures, it will be necessary to break-down the pile and create a new one; an unpleasant job to say the least.
Why is it so important to maintain an internal temperature of 130-160 degrees? Aside from odor and decomposition considerations, it's important for you to ensure the majority of pathogens are killed during the decomposition process so as to avoid contamination. 140-160 is the ideal kill point for such pathogens.
I recommend checking the temperature daily at first, and then every other day once you know the composting process is going well. If temperatures slip below 130 degrees after the initial few days, make sure your pile contains the appropriate nitrogen levels, that your compost materials allow enough oxygen flow throughout the pile, and that you're not applying too much water to the pile.
Typical Composting Periods
Large animals such as a horse require a composting period of approximately 75-90 days. (As a point of comparison, smaller animals require about a month.) Once the 90 days has passed, the composting process is finished, but you should allow the compost contents to sit another 90 days before applying it to gardens or soil as fertilizer.
Once a compost is finished, you may find some bone remains, but the rest of the horse carcass will have decomposed into a rich fertilizer.
Final Caution Regarding Composting
I know I've warned you to prepare and monitor your compost pile carefully throughout this article, but at the risk of sounding like a broken record, I'd like to again emphasize that you must monitor a compost pile if you go this route. An improper compost pile can pose significant health risks, attract undesirable vermin and flies, and send obnoxious odors to your home or those of your neighbors.
If composting a dead horse sounds like too much work or worry to you, chances are it is. I personally do not recommend this route of dead horse removal for anyone that doesn't know exactly what he's getting into. It works, it can be environmentally friendly, but it's not nearly as simple as a horse burial or taking advantage of a nearby landfill.