Location	Camp Muir – Mount Rainier National Park, Washington
Toilet Type	Waste Away
Building Type	Retrofit (of a failing evaporator)
Vault Type	Barrels
Seat Type	BTW (7 units on the mountain)
Usage Rate / Description	Seasonally > 200/day
Solid Waste Retention	1/5 of the previous barrel fly outs
Temps / Elevation	18F to 45F / 10,188 ft
Start-Up Year	2016 & 2017

History of Camp Muir Toilets--pdf

At Camp Muir, two stone buildings were constructed on the north side of the public shelter in the 1920’s. Ramps were built under the seats, and the waste solids would fall into a crevasse at the bottom of the slope behind the buildings. If there was a buildup of solids, the climbing ranger would rake the material down hill into the crevasse. The system was redesigned by the late 60’s and utilized five gallon cans lined with plastic bags under the seats. The full bags were then disposed into the crevasse.

The first pit toilet at Camp Muir was constructed in 1966 and the second in 1971. The permafrost made digging the pit difficult and time consuming; only about 6 inches per day could be dug on a warm day, with 2 inches per day the average. The pit toilets were four feet by four feet by six feet (depth). Both toilets were open during the summer, and one was kept open during the winter. Park personnel would use a posthole digger and scoop shovel to place waste material into 55-gallon drums. The pits were cleaned out twice a year and the drums, containing primarily solids, were flown out by helicopter.

In 1968 a propane assisted toilet was installed at Camp Muir in order to incinerate wastes. However, serious injuries occurred while a user was incinerating the wastes and the toilet was abandoned.

In 1972 a Jet-O-Matic Chemical Toilet was installed at Camp Muir. This system required five to six gallons of ethylene glycol in order to charge the reservoir tank and three gallons of a formaldehyde based solution placed in the holding tank solution for each 160 uses. When the sewage holding tank was full, the materials, including solids, liquids, and chemicals, were flushed into 55-gallon drums and flown out. Several problems occurred that forced the abandonment of this system. An adequate supply of water was not available to the system and the flush water did not recirculate, causing piles of materials to accumulate directly beneath the seat. The material in the full tank was difficult to flush into the 55-gallon drums because the concentration of solids was too high. At least 660 gallons of waste from the chemical alone had to be flown off the mountain in one year.

In 1974 an indoor toilet system was installed in the public shelter at Camp Muir. A curtain was placed around a toilet seat in the corner, and plastic bags were supplied. Plastic bags were then placed in 55-gallon drums and later flown out. However, many visitors preferred more private locations and the system was eventually abandoned.

In 1978 four vault toilets were installed at Camp Muir. Two were eventually replaced with pit toilets and the remaining vaults were removed in 1984. The urinals did not drain well due to the permafrost. Consequently, liquids and solids had to be removed by hand and stored for helicopter removal at the end of the season. The used vaults were exchanged several times a week for empty ones and stored in racks.

In 1983 a waste composter bin had been proposed for installation in a crater steam cave. This system included a basket approximately one foot square made of wire mesh that would hold the waste and allow aerobic bacteria to encourage decomposition. Installation was planned for one of the vent caves where temperatures remain above freezing. However, a suitable vent cave could not be located and the project was abandoned.

In 1984 a prototype solar assisted composting toilet was installed at Camp Muir with the assistance of the U.S. Public Health Service and the Maintenance and Engineering personnel at the NPS Denver Service Center under the Remote Area Management Waste Disposal (RAWAD) project. The RAWAD project was an effort made by the NPS to document and identify appropriate systems for backcountry human waste disposal by assessing performance of existing facilities; installing demonstration facilities; and to identify and review new or potential technological applications that might be available. The cost to design, construct, install and modify the solar assisted structure (at Camp Muir) was from $50,000 to $75,000.

Although significant biological decomposition of human wastes would be difficult at high elevations on the mountain, the effort was directed towards reducing the volume of wastes by evaporating the liquids and drying the solids. The drying process was assisted by heating the air and/or the liquid, so solar energy was used to provide as much thermal energy as possible. However, the number of uses this facility received (6,000 in less than two months) and other mechanical problems resulted in the accumulation of liquids which were evaporating at a very slow rate and resulted in at least 500 gallons of liquids that had to be flown off the mountain (not sure what year or years). In 1988 a leach field was installed and approximately 400 to 600 gallons of waste liquid was run into the ground below the permafrost level. As a result the solids were reduced in weight by 50% with a 75% total waste reduction. However, the overall ecosystem effects of the disposal of waste liquids through the leach system are unknown. This toilet remained in use until 1999. The large vault that the liquids went into was a block of ice for most of the year and never fully melted even in August. Liquids did flow out of the toilet into the leach field.  In 2000 the toilet building was removed and the remaining liquids and ice removed from the vault. Approximately half of the vault was filled in with soil and rock and the rest of the vault was used as a pit for a toilet, which was primary used in the winter (October through May). The drain to the leach field, which was installed in 1988, is still in use in 2016. Approximately 100 gallons of solid waste is removed from this toilet each year (2000 through 2016). To remove the waste Park staff use posthole diggers and place the waste in 55-gallon drums, which are flown off the mountain in either June or September.

In 1998 the first of three “solar dehydrating toilets” was installed at Camp Muir. This type of toilet was first used at Camp Schurman, where it was installed in August of 1996. The design was a modification of the 1984 prototype solar assisted composting toilet. Instead of having the large vault to collect liquids the liquids went into a four-inch deep pan four feet by four feet with a drain where any remaining liquids went into the leach field below the toilet. The solid wastes were collected in stainless steel baskets above the pan. The baskets and pan were in an enclosed structure on the south side of the toilet made of Lexan, a clear polycarbonate sheet. Solar radiation heated the enclosure during the day to well over 100 degrees F on a sunny day.  The toilet was designed this way to enhance evaporation of liquids from the pan and dehydrate the solid wastes in the baskets. To further assist dehydration and remove smell, a four inch 12-volt fan was installed and run off a battery charged by a photovoltaic panel. The chamber where the waste accumulated was large enough to store 6 baskets. Each basket could hold up to 10 gallons of solid waste. The baskets were rotated in the chamber about every third day (depending on use) to allow for the solids to dry in the chamber. Under perfect conditions each basket would remain in the chamber for 15 to 20 days and would then be removed and dumped into a 55-gallon drum. This would allow for the maximum dehydration of the solids, which would reduce the number helicopter flights required to remove the waste from the high camps.

The last of the solar toilets at Camp Muir was installed in 2000 and three toilets were in use during the summer from 2001 to 2016. All four of the toilets (3 at Muir and 1 at Schurman) have been very smelly. This is largely due to the fact that the urine and feces are mixed together in the baskets and then the urine collects in the pan below the baskets. This mixture of fecal bacteria, urine and heat created an odor problem. The pan where the urine is collected usually has a two-inch thick layer of slime by the end of the summer season. In addition, this design means that the liquids exiting the pan are extremely contaminated with fecal material before entering the leach field. Although the toilets have vents and fans to move air through the heat chamber, they were poorly designed and very ineffective at removing the smell from the toilet. In addition, any odor that was removed was blown out into the Camp Muir area at about 6 feet above the ground, making the whole Camp smell of human waste.

In 2013, Mount Rainier staff designed a toilet to hopefully eliminate the problems associated with the previous toilets. First a leach field was designed by an engineer and installed below the proposed toilet. The new toilet is being constructed in the northeast corner of the Camp so hopefully the prevailing southwest winds will carry any odors away from Camp most of the time. A solar hot water heating system is being installed to keep liquids from freezing until they can be dosed into the leach field during the summer (July through mid-September).  Construction on the new toilet began in 2014. In 2016 the Park purchased three urine separating toilets (ToiletTech Behind-the-Wall (or BTW) seats) for use in the toilet when completed. 

The three existing solar toilets at Camp Muir were modified to accommodate the TTS BTW  urine separating toilets in the summer of 2016. The first toilet was modified and the urine separating toilet installed in early July. The other two toilets were converted in August and September.

The urine separating toilets at Camp Muir worked well and there was a noticeable improvement of the smell in the toilets. The solid human waste from the toilets was collected directly into a 55-gallon barrel. This eliminated the need to transfer waste from the collection baskets in the old solar toilets to 55-gallon barrels. Previously, this was a difficult and unpleasant task. The  liquids from the toilets that were are now piped directly into the leach field below the toilets is urine only, as source separation happens prior to urine passing through fecal matter.

The biggest concern that Park staff have is how well the system will work in the late spring (May-June) when there are increased numbers of climbers but the temperature is below freezing most of the time. The existing toilets at Camp Muir that were retrofitted to accommodate the urine separating toilets currently have no external heat source.  There is the possibility that solar hot water panels could be added to the existing toilets to provide heat. The new toilet, which is being constructed, should have enough warmth from the solar system and propane heater to allow the liquids to flow into the storage tank.

UPDATE SEPT 2019 - no external heat source has been needed.