Added slides for Commercial Use

1. Continuous Composter Tanks
Sarah Allen. Spring 2015. Luke Kwan. INTA332 B

2. What do they do?
• A composting (or
biological) tank system
contains and processes
carbon additives, food
waste, some types of
animal waste, and
natural fibers such as
paper based products.

3. How does it work?
• Unlike a septic system, a composting system relies on
unsaturated conditions where aerobic bacteria break down
waste.
• Waste is contained, and most odor is limited due to enclosed
vessel.
• Some units end contents can be used for gardening along with
mulch. Other container systems use the gas omitted form the
composting process as cooking fuel

4. Composting Cycle
Considering the contents of tanks,
they are primarily installed
outdoors.
Sizes can range from small
households use for gardening, to
larger applications such as farms
Smaller units can be constructed at
home, while large pieces can be
ordered pre fabricated.

5. The “Other” Tank

6. Types of composting toilets
Batch Composting
Continuous Composting
Hybrid Composting

7. Waterless Composting Toilet Tanks
• Solid waste is collected in a small compost chamber
directly beneath the toilet pedestal. A low powered
electric fan circulates air through the chamber speeding
the composting process and eliminates odors. Liquids
are separated from solids and evaporated by the fan.
Any excess liquid is dispersed into a small trench
Nature Loo Composting Toilet

8. Installation
Installation of these composting
tanks take more than the basic
plumbing needs of the typical
toilet. There are drain hoses
(10ft or more), Vent stacks,
diffusers, and roof flashings.
Basically you are installing an
additional “ante chamber”
outside of the bathroom to
collect the waste and keep it
contained in needed
temperature levels, and prevent
odors from escaping

9. Types of Tanks

10. Commercial Use of Composting Toilets
• An increasing number of commercial buildings have
successfully incorporated composting toilets into their
operations. They are now found in city and state parks,
schools (see Bertschi School in Seattle, WA and College of the
Atlantic in Bar Harbor, ME), churches (Canterbury Diocese,
England ), and offices (Bullitt Center in Seattle, WA). Many
building like these have incorporated these factors in to
meeting the Living Building Challenge

11. Living Buildings
• The Living Building Challenge is the built environment's most
rigorous performance standard. It calls for the creation of
building projects at all scales that operate as cleanly,
beautifully and efficiently as nature's architecture. To be
certified under the Challenge, projects must meet a series of
ambitious performance requirements over a minimum of 12
months of continuous occupancy.

12. The Bertschi School Living Science Building
• All the sustainable features of the building are
visible and functional for students to learn
ecological concepts that can become intrinsic
values for future generations. Because the building
must have net zero water and energy usage,
students participate in real-time monitoring of the
building's energy use and production, as well as
the water usage and collection. Daily operations,
systems monitoring, and maintenance are carried
out by the Science teacher and facilities staff, with
help from students and volunteers

13. Composting Toilet
• Water needed for the building is captured rainwater for all
non-potable uses. City water is provided at the classroom
sinks due to code requirements. Net zero water is achieved
through a variety of methods including cisterns for storage,
an interior green wall which treats grey water, and a
composting toilet to treat black water. Excess captured
water is absorbed by the on-site rain garden.

14. • The Science Wing has one unisex restroom with a composting toilet. The system employs a
vacuum flush Envirolet composting system consisting of a toilet unit, vacuum/pulverizing unit,
and two composting waste storage tanks. The dual tanks add capacity and allow for an average
of fifty flushes per day. Each flush uses approximately one pint of rain water.
•
•
•
• This system was chosen due to space constraints and the inability to have the composting unit
directly below the toilet. While the vacuum system solves the space and location problem, it
uses more energy than a gravity type composting system because of the need to move waste
under vacuum and the additional heat required to evaporate the water required to flush.
•

15. Bullitt Center
• The Living Building Challenge requires all water to be
harvested and treated on site. To meet the Challenge with
respect to management of human waste on site, the Bullitt
Center team is using Phoenix Composting Toilets from
Advanced Composting Systems of Whitefish, Montana
• To date, the Phoenix Composting Toilet has been installed
only in one or two-story structures.

16. • When a user comes into the stall there is a sensor that can tell if it
is a “sitter” or a “stander”. The tank of the toilet contains a soap
solution, an air compressor, and water. The soap solution is
introduced into the toilet. After use, the waste travels down into
one of the 10 composters located in the basement of the building.
Each of these units is 84” tall x 40” wide x 61” deep. Inside the
composter wood shavings and water combine with the waste,
causing it to decompose through the action of aerobic bacteria. A
handle on the exterior rotates tines inside the composter. The tines
are manually rotated to mix the decomposing waste in order to
oxygenate the mixture. Most of the waste is converted into carbon
dioxide and water vapor. Leachate gets re-sprayed onto the
mixture and there is also a leachate tank to receive any excess.
Stabilized leachate is pumped to a vacuum port in the alley where
it is picked-up on a monthly basis and taken to a facility where it is
combined with other field-ready compost streams. On a regular
basis, wood chips will be added to the composters and a small
amount of compost will be removed. Sensors and alarms located
on each of the composting units will monitor their operation.

17. Application
• Commercial building operators may face different legal
challenges than homeowners when it comes to waste
management. Projects seeking Living Building status must
have a closed loop water system, meaning all water supply
needs must be met on-site and all wastewater must be
processed and used on-site. Even buildings that have a
greywater processing/recycling system and composting toilets
may need a backup sewer line to meet building codes.
Simultaneously meeting building regulations and project
water goals will require negotiation and possibly added cost
(for example, installing a sewer connection even if it will not
be used).