Barrel Composting Toilet
Urine separation is an integral component of the Barrel Composting Toilet System. The recommended system for urine diversion is described below. The system consists of 2 basic assemblies: a urine diverter built into each barrel and a hose to transport urine to an approved drainage system.
For outdoor installations, check with your local regulator to see if the subsurface leaching chamber system described below may be approved. One leaching chamber is required for each barrel. Also described below is an optional urinal for men. Perennial plants located near the leaching chambers are recommended for uptake of water and nitrogen in the urine.
For information on the sizing of the bucket leaching chamber, see Barrel Composting Toilet System: Calculating Effective Leaching Chamber Sizing for Subsurface Disposal of Urine
The diverter is made from a Super Quick Fill funnel available at auto parts stores. The drain hose is 1/4" fuel line. The reason for the small diameter hose is that urine is high in dissolved minerals that will precipitate over time on the inside of drain pipes. Rinsing the urine diverter after each use requires only 1/4-1/2 cup of water to thoroughly clean the entire inside surface of the hose, thus preventing mineral formation. A stainless steel screen prevents clogging of the hose. Also, in the unlikely event that clogging occurs, a plumbing "snake" can be inexpensively constructed as described in the "Troubleshooting" section of the Barrel Composting Toilet System: Owner's Manual
Another advantage of the small diameter hose is that it prevents insects from entering the toilet from the leaching chamber via the hose.
Notes on construction:
--#10 stainless steel fasteners are used for securing the urine diverter to the barrel, for securing the urine drain cable clamps to the barrel and for securing the men's urinal to whatever surface it's mounted on. Holes for these fasteners should be drilled using a 3/16" diameter drill bit.
--The two holes for mounting the urine diverter to the barrel should be centered on the front of the barrel, about 2" and 3" below the lip at the top of the barrel (see photo above). Inserting the urine diverter fasteners through these holes is easier if the holes are a bit larger than 3/16" diameter (7/32" is good)
--The hole for the urine drain hose to exit the barrel should be 1/2" in diameter and centered on the front of the barrel, about 12" below the top of the barrel.
--The urine drain hose from each barrel will go into a hole drilled near the top of the leaching chamber. Both of these 2 holes should be 1/2" diameter.
--Take care to be sure that hoses are level or downhill all the way from urine diversion funnels to leaching chamber. If not, air bubbles may form in uphill sections, preventing urine from flowing.
--Insert the hose into the funnel (this applies to both the urinal funnel and the diverter funnel), then press the hose into the rubber stopper. Use soapy water on the end of the hose and on the rubber stopper to help get the hose into the stopper. Gently press the stopper down into the funnel for a liquid-tight seal.
Notes on use:
--After each use of the urine diverter or men's urinal, rinse the inside with a couple squirts of water from the water bottle located by the toilet.
--The urine diversion system so effectively keeps urine out of the toilet barrel that some urine or water may have to be poured back into the barrel periodically to maintain sufficient moisture for effective decomposition.
--Occasionally pieces of cover material may fall into the urine diverter. If so, remove the screen from the diverter, turn it upside down and spray it clean with squirt bottle used for wetting toilet paper.
--Check bottom of diverter occasionally to be sure rubber stopper around urine drain hose is snug. A loose stopper can allow excessive amounts of urine to enter the active barrel, causing anaerobic conditions and resulting odors.
--See the "Troubleshooting" section of the Barrel Composting Toilet System: Owner's Manual
Materials List for Urine Diversion System
Urine Diverter (per barrel):
--Funnel, FloTool Super Quick Fill
--Funnel, FloTool Giant #
Leaching Chamber (per barrel):
--5 gallon plastic bucket, 1 @ $4.00
$4.00 (Hardware Store)