Guest Contribution: Composting your Pee February 04, 2014 14:11 4 Comments

Follow guest contributor Dylan Rawlyk at his blog, http://tothrowforward.blogspot.ca.

For the past while I've been composting my pee as a way to increase nutrients for my garden, to reduce my water use, and to reduce my wastewater impact. I plan to walk you through my current method, as it works quite well. This may not be for everyone, but some of you may become inspired.  

Why I compost my pee instead of flushing it down the toilet. Our toilets are filled with drinking water. This water comes from three finite reservoirs near North Van that are replenished solely from snowmelt and rainfall on the mountains, and is treated before reaching our toilets. How ridiculous is this that we use a finite resource, treat it with more resources and energy, waste it, to just treat it again, and leaving the end wastewater not as clean as it started! Furthermore, as our population in Metro Vancouver continues to grow, our water treatment and wastewater treatment centres are strained, needing very expensive upgrades and expansions to keep the system running properly. By composting our pee, we can reduce our water consumption, while keeping our nutrients in a closed-loop system benefitting our gardens, instead of polluting our waterways.  

What you’ve got to know. Urine by itself is sterile, as opposed to poo, making it easier to safely compost. It is also very high in nitrogen (great for plants), and is water-soluble. So if we were to just put our urine on our garden, there’s a high chance we’d overdo it with nitrogen, and might kill the plants, and any excess nutrients will leach from the garden with water infiltration, and will be lost, potentially polluting other areas. So, to compost your pee, we need to get it in a less mobile state, and reduce the nitrogen concentration. Typically, an efficient compost system relies on having a balance of carbon and nitrogen. In compost, this means balancing your waste products to have a 20:1 – 35:1 carbon:nitrogen ratio. Urine, by itself has a carbon:nitrogen ratio of about 0.8:1. That being said, we must add a lot of carbon (woody material) to balance it properly for our compost systems. So I’ve experimented with multiple woody materials. I suggest using waste products from around you if possible, such as twigs, fall garden stalks, local sawdust, leaves, maybe even cardboard. These days, I’ve been using a bought carbon source. It’s cheap, compacted so takes up less space, and works extremely well. It’s called pet bedding or wood pellets. It’s very easy to see when this carbon source is balanced with your urine because it expands, and all the liquid should be absorbed into the sawdust. Lastly, if you are dumping the pail often, and balancing your urine with carbon, this will not stink up your bathroom.

How I do it. 1)   Find a large pail that can be stored next to your toilet. 2)   Cover the bottom of the pail with your chosen woody material. 3)   Urinate in the pail. If you prefer to sit when you pee, you can attach a toilet seat to the pail. 4)   Put a handful of woody material on top. 5)   Repeat until pail is close to full. 6)   Dump it onto your compost pile. 7)   Repeat.

Things to keep in mind. This is a very simple process and if you are a bit off on your nutrient ratios, your compost system should be able to still balance it out. It is very important to have a diversity of waste products going into your compost system, so don't overload it with your urine mix. Make sure you have other waste products going in too. It’s helpful to have a wingdigger or similar tool to mix and aerate your compost bin. It’s good to have the balanced urine/wood mix distributed within your compost system. The nutrients found in our urine came from the food we ate, which in turn came from farms and gardens. Composting our urine returns those nutrients back to where they came from, instead of them getting lost to the ocean. Experiment. Observe. Learn.