City Services Building –
Exhibit D: Cutting Edge Technologies: Agencies and Precedents
Exhibit D: Cutting-Edge Technologies: Agencies and Precedents
1 Net Zero Water
The International Living Future Institute (ILFI) describes the Living Building Challenge (LBC) as
a rating system, advocacy tool and philosophy. ILFI promotes LBC as an advocacy tool
because projects endeavoring to meet the rigorous requirements of the rating system often
encounter outdated regulatory codes that prevent maximum efficiency from innovation. The LBC
process daylights opportunities to reassess these barriers and places practitioners in a unique
position to collaborate with regulatory agencies on updating codes.
Net-zero water (NZW) is identified as the LBC requirement most associated with regulatory
challenges. NZW is an approach to development where the available water supply at the project
site equals the project water demand. The available water supply is often defined by the amount
of precipitation that falls on the project site and any other water that is captured and treated on
site.
During project planning, it is critical that the estimated available water supply informs the project
programming in order to find a match between water supply and demand. For the City Services
Building (CSB), the City of Santa Monica (CSM) identified potential water supplies that could
contribute to the project’s NZW goal but were either unregulated or explicitly prohibited by
county, state and federal regulations. Early discussions with the CSB design-build consultants
indicated there were opportunities to argue these alternate water supplies could be safely
implemented and provide the most water efficient building possible with no adverse risk to
human health or the environment. There are examples of other California projects that have
been granted regulatory variances and numerous case studies from other states and countries
that demonstrated California is not yet enabling viable sources of water in buildings.
While endeavoring to meet the Living Building Challenge, per council direction, it became
apparent to the project team that multiple Net Zero Water (NZW) cutting-edge technologies
must be employed including composting toilets, rainwater to potable water system and
advanced reuse of grey water. In order to utilize these systems in the CSB project, state,
regional and local agencies must agree to allow for their construction, use and maintenance.
The City staff including the City’s Office of Sustainability and the Environment (OSE), Public
Works Administration, Water Resources Division, Architecture Services Division, and the CSB
design-build team have initiated meetings and discussions with regulatory bodies early in the
project design process. The project team has been working through challenges together with
the required agencies in order to promote and coordinate these systems and to encourage the
evolution of codes and best practices in California. This should allow for the emerging
technologies and high performance systems to meet health and safety standards and to be
approved for use in the CSB project.
After a thorough research process, including conversations with practitioners around the world,
the City has met with regulatory agencies to share what we had learned. This included, but is
not limited to, the following meetings:
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Meeting
Date
Los Angeles County
Department of Public
Health
September 2014  LBC
 Compost
toilets
Topic(s)
Seattle Water Forum
January 2015
 Bullitt Center
Permitting
 Compost
toilets
 Rainwater to
potable
 Graywater to
edible
landscape
California State
Division of Drinking
Water (DDW)
December 2015
 Rainwater to
Potable
 Groundwater
well to potable
 Graywater to
edible
landscape
Attendees
 LA County Health –
Environmental Protection
Senior Staff
 CSM OSE
 CSM Architectural Services
 CSM Public Works
 Bullitt Foundation
 ILFI
 King County (WA)
 State of Washington
 Bullitt Center Designers
 LA County Health –
Environmental Protection
Senior Staff
 CSM OSE
 CSM Architectural Services
 CSM Public Works
 CSM Building & Safety
 CSM Facilities Maintenance
 CSM Plumbing Plan
Check/Inspection
 CA Regional Water Quality
Control Board (RWQCB)
 CA DDW
 LA County Health –
Environmental Protection
Senior Staff
 CSM OSE
 CSM Architectural Services
 CSM Public Works
 CSM Building & Safety
 CSM Water Resources
 CSB Design-Build Team
Each of these meetings resulted in acknowledgement that the proposed strategies are
technically feasible at the building scale and can be evaluated collaboratively moving forward.
Details of the systems in the context of California regulations will be discussed in this report.
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Figure 1: This flow diagram illustrates a conceptual net zero project that includes rainwater harvesting and
the use of non-potable water for foam-flush composting toilets. Source: Biohabitats, Inc.
2 Net Zero Strategies
2.1 Potable Water from Rainwater
System Description
A rainwater harvesting system consists of an area to collect rainwater, a place to store water
(cistern), and a treatment system to filter and disinfect rainwater prior to reuse. Rainwater is a
relatively clean drinking water source, therefore rainwater harvesting systems should be
designed to minimize degradation of this high quality water. Collection, or catchment, areas
should be located in close proximity to where water will be stored and must consist of materials
that do not contaminate water with pollutants.
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Figure 2: An example of a rainwater harvesting system to provide potable water
Source: Biohabitats, Inc.
Catchment areas may have photovoltaic (PV), solar thermal systems or other similar systems
that are safe for collection of rain water. Rainwater will land in the catchment area and be
directed to collection network. Rain will be screened to remove coarse debris, and then stored in
a cistern. Rainwater stored in the cistern will require filtration and disinfection prior to use. The
City is committed to implementing a rigorous monitoring, testing and reporting program in
accordance with guidelines from the applicable regulatory agencies.
Basis of Design and Precedent Projects
Roof material should meet NSF P151 certification (Appendix K of California Plumbing Code)
and may include inert mechanical systems, such as PV panels, within the collection area. The
predominant type of PV panels available on the market today are made from monocrystalline
silicon modules, also referred to as “safety glass.” Panels sometimes include an antireflective
coating (ARC), made from silicon dioxide. Silicon dioxide is an inert silica compound that is
approved by the U.S. Food and Drug Administration (FDA) for consumption.
Rainwater from the roof will go through a screen before it enters the cistern. This screen will
prevent large debris, such as leaves, from accumulating in the cistern. Water leaving the cistern
will be filtered using a series of bag or cartridge filters. They are available in various sizes, to
accommodate the design flow rate through the filter. For potable supplies, systems should
include redundant disinfection.
Potential disinfection systems include chlorination, UV, carbon or ozone. Chlorination is the
most widely used chemical for water disinfection, utilized by most municipalities for their drinking
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water. Chlorination is relatively inexpensive, simple to administer and its presence in treated
water can be measured, often referred to as a chlorine residual. However, the use of chlorine
has several negative implications including the creation of carcinogenic disinfection by-products
(trihalomethanes), contribution to chlorine resistance in bacteria, and taste. UV lamps require
regular cleaning, periodic replacement and energy to operate. UV does not create any
disinfection by-products and pathogens do not develop a resistance to UV as with chlorine.
Activated carbon filtration does not require moving parts, but must be replaced periodically as
the filter loses capacity. Ozone must be manufactured on site and safety accommodations must
be made within the mechanical room to avoid any concentration of ozone if it were to leak from
the production tank. UV, carbon filters or ozone are often used in cases where certain chemicals
must be avoided, for example, within Living Building Challenge (LBC) projects.
Below are several precedent projects that collect rainwater from a catchment area that includes
PV panels and treat it for potable use.
Table 1: Precedent projects in the United States that utilize PV panels in their potable water catchment area
Project Name
Chesapeake Bay Foundation’s Phillip Merrill
Environmental Center
Bullitt Center
Chesapeake Bay Foundation’s Brock
Environmental Center
Location
Year
Constructed
Annapolis, MD
2001
Seattle, WA
2013
Virginia Beach, VA
2014
Design and Operational Considerations
The design of a roof rainwater harvesting system may choose to exclude the “first flush” or the
first runoff from the roof into the cistern after an extended dry period. In a climate like Santa
Monica, the first flush may be a large percentage of a single rain event and it is therefore
preferable to implement a regular maintenance program to keep the catchment (proposed: roof
and PV panels) area free of debris and plan for first flush contaminants (including bird
droppings) in the design of the treatment system. The filtration, disinfection and testing process
described above would adequately address bacteria concerns associated with bird droppings.
A potable rain harvesting system will require a detailed Operations and Maintenance Plan to
ensure that system components are maintained in optimal condition. For example, PV panels
will need to be inspected regularly to identify any damage and maintained according to
manufactures’ specifications. PV Panels are a relatively resilient system with strict
manufacturing standards. Panel manufacturers are subject to standards from the Underwriter
Laboratories (UL), International Electro-technical Commission (IEC), and the International
Organization for Standardization (ISO). Panels withstand standard testing conditions that
replicate 1 inch diameter hail hitting panels at 50 mph.
The screens that remove coarse debris, before rainwater enters the cistern, must be inspected
at least once a week and cleaned regularly. The cistern used to hold rainwater may occasionally
need to be drained and cleaned to remove the sediments that have passed through the initial
screen and accumulated on the bottom of the cistern. The frequency of draining and cleaning
the cistern will depend on sediment impacts to water quality. The ongoing maintenance and
inspection will be integrated into the monitoring, testing and reporting program described above.
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2.2 Composting Toilets
System Description
Composting toilets can significantly reduce a project
water demand when compared to a traditional project
that uses flush toilets. In the CSB, it is estimated
composting toilets would save 228,000 gallons of water
per year. Options for composting toilets include dry
toilets that are similar to a pit toilet, where waste falls
directly down to a composter. A more common
approach for commercial applications, and the type
proposed for the CSB, is the use of a foam flush
composting toilet, which uses as little as 6 ounces of
water per flush and has an appearance similar to
standard toilets. The small amount of water needed for
the composting foam flush toilet can be supplied by
treated greywater to further reduce the potable portion
of the project water demand.
Several brands and types of composting toilets are
available for residential or commercial applications. The
Phoenix composting toilet is the type used in the Bullitt
Center and has the most history of use in a mid-rise
building. This system has been proposed for use in the
CSB. Rather than flushing with water, a continuous
Photo 1: A composting foam flush toilet
layer of foam is distributed around the bowl and
at the Bullitt Center in Seattle, WA.
transports waste down into a composter. The foam
consists of a soap called Neponol, a biodegradable
alcohol-based surfactant.
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Figure 3: One possible treatment path for composting toilet leachate and solids
Source: Biohabitats, Inc.
Composting toilets are piped to composter units located below bathrooms, often in a basement
level. The composting unit is vented to the roof, maintaining a constant negative pressure in
order to avoid odors. This means air in the bathrooms is constantly being drawn into the toilets,
through the composting units and out of the building at the roof.
The length of time that the compost remains in the composter unit will depend on the amount of
use that the units receive and the temperature where the composter units are located.
Composting toilets experience optimal decomposition when the composter room is kept at 65
degrees Fahrenheit (F). Urine and any additional water added to the composter units will result
in the formation of leachate. This liquid is high in nutrients and may be treated for landscape
application. The system represents the Living Building Challenge goal of buildings designed to
be resource producers instead of resource consumers.
Basis of Design and Precedent Projects
Composting toilets convert human waste to humus through the process of aerobic degradation.
Bacteria breakdown the waste into simple organic compounds that can be used as a soil
amendment. Additional forms of carbon are needed for this process, so sawdust or wood chips
must be added to the composter units on a regular basis. The composter units may also
incorporate worms, or vermicomposting, further aerating the compost and contributing to waste
conversion. Compost produced from the Phoenix composter units is classified as an EPA Class
B biosolid. The process also produces a leachate by-product. At the Bullitt Center these two end
products, Class B biosolid and leachate, are removed from the building periodically and
transported to off-site locations for further treatment. This is not the optimal solution for
managing what should be considered resources that contain beneficial nutrients. As indicated
above, the Phoenix composting system is currently being proposed for the CSB. It is the intent
of the CSB design-build team to identify a design approach that would allow the project to meet
the true requirements of LBC and reuse these resources on site.
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Uniform Plumbing Code (UPC) Section 406.3 defines composting toilets as a dry toilet. The
Phoenix system does not apply under this code, because it is not a dry toilet. The California
Plumbing Code (CPC) Title 24, Part 25, Section 601.1(3) identifies a requirement that “water
closets and urinals shall be flushed by means of an approved flush tank or flushometer valve.” If
the flush mechanism is not CPC approved, there may be need to apply for an exemption.
The International Association of Plumbing and Mechanical Officials (IAPMO), who create the
UPC, recently released the 2015 Green Plumbing and Mechanical Code Supplement (GPMCS),
which recommends compost toilets as a regulated process in the plumbing code. Additionally,
IAPMO plans to use the 2015 GPMCS as its basis for a water efficiency and sanitation
American National Standard (ANSI) to be known as WE•Stand 2017.
With the goal to manage composting by-products on-site, the CSB project is proposing
disinfection by pasteurization. An onsite pasteurization unit can be used to treat the compost
taken from the composter units to EPA Class A biosolids standards. Class A biosolids are safe
for handling and can be readily applied to the landscape. Pasteurization would require that the
compost is heated to 158 degrees F for 30 minutes to achieve designation as a Class A
biosolid, in accordance with EPA Standard Title 40 CFR part 503. The compost will need to be
tested for fecal coliform and volatile solids content to ensure that it meets Class A designation.
Pasteurization can also be used to reduce pathogens in leachate and make it safe for land
application.
Composting toilets have been installed in commercial and residential settings throughout the
United States for decades. The Bullitt Center provides an appropriate precedent for using
composting toilets on a commercial scale, with 25 composting toilets and 10 composter units.
The Phoenix units have been operating under regular use since 2013, providing practical
operations and maintenance experience. Public project precedents in California include the San
Jose Environmental Innovation Center and El Polin Spring at the Presidio. The San Jose
Environmental Innovation Center uses foam flush composting units. The Chesapeake Bay
Foundation’s Brock Environmental Center, in Virginia, incorporates the finished compost from
their composting toilets into the surrounding landscape. Table 2 lists projects throughout the
country that have utilized composting toilet systems, along with the year that they were built.
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Table 2: Projects in the United States that utilize composting toilets
Project Name
Location
Year
Oakes Hall at Vermont Law School
South Royalton, VT
1998
Chesapeake Bay Foundation’s Phillip Merrill Environmental Center
Annapolis, MD
2001
Islandwood
Bainbridge Island, WA
2002
Debevoise Hall at Vermont Law School
South Royalton, VT
2005
Bronx Zoo
New York, NY
2006
Bertschi School
Seattle, WA
2010
El Polin Spring, in the Presidio
San Francisco, CA
2011
Stroud Water Research Center
Avondale, PA
2012
Bullitt Center
Seattle, WA
2013
Chesapeake Bay Foundation’s Brock Environmental Center
Virginia Beach, VA
2014
San Jose Environmental Innovation Center (SJEIC)
San Jose, CA
2014
Hard Bargain Farm
Accokeek, MD
2015
Design and Operational Considerations
Design considerations for a composting toilet system should include space allocation and
maintenance access. Composting toilets should be clustered within the building so that multiple
toilets can contribute to a single composter unit. Composter units will be located below the
bathroom facilities with composting toilets. The composter units will also require maintenance
access for biosolids and leachate handling.
Building users will require education about how to use the composting toilets. Only biodegradable products can go into the composting toilets and only non-toxic cleaning agents
should be used. The composting toilets will require periodic cleaning and monitoring of soap
levels for the foam flush process.
The composting units will require specific monitoring and maintenance, which will be outlined in
an Operations and Maintenance Manual. Items to include in the manual will include the addition
of bulking material (sawdust), monitoring compost moisture, mixing the compost, trash removal,
compost and leachate removal, and troubleshooting guidance for possible problems. The
frequency of maintenance of the composting units and biosolids management will vary
depending on the amount of use that the units receive. Approximately one gallon of bulking
agent will need to be added for every 100 uses. It is likely that the leachate will need to be
pumped out of the composter units approximately once per week. Based on the experience with
other projects, the finished compost may only need to be removed once a year, as the Bullitt
Center had their first complete removal after about 18 months and the volume was only 12 cubic
feet. The process of aerobic degradation, combined with vermicomposting, effectively reduce
the volume of solids, thereby limiting the frequency of removal. The Bullitt Center has
approximately 250 occupants. The CSB, for comparison, will have 239.
The mechanical and electrical systems associated with the composting toilets must be
monitored regularly to ensure proper ventilation. The ventilation system must be designed with
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redundancy to ensure proper air quality while components are being maintained. Backup power
must be allocated for this system in the case of power outages.
2.3 Greywater
System Description
A greywater treatment and reuse system typically consists of a screened catch basin, ahead of
a secondary treatment process to treat biochemical oxygen demand (BOD) and total suspended
solids (TSS), and mechanical filtration. When the end use of treated greywater is for indoor
applications, such as toilet and urinal flushing (including composting toilet foam flushing), or
floor drain trap priming, disinfection is required. Onsite treated non-potable greywater systems
in California are required to be certified by NSF 350, and there are multiple treatment products
available for use. Additionally, the recently published Alternate Water Reuse Guidelines (Matrix
2.0) from the Los Angeles County Public Health Department establish clear criteria for the
outdoor and indoor reuse of treated non-potable greywater. The only irrigation required for the
CSB will be for urban agriculture (a Living Building Challenge requirement). Although the
plumbing code and Matrix 2.0 do not require disinfection of greywater for subsurface irrigation,
the CSB will take additional precaution because of land application to an edible landscape zone.
Currently, it is anticipated regulatory agencies would consider wastewater from kitchen sinks
and dishwashers as blackwater, however there is reason to believe this is not the appropriate
method for regulating this source of water. By working with governing agencies, this can be
modified, reinterpreted or approved by variance. Numerous other states would classify this
water as greywater and this distinction is critical to treatment and ongoing monitoring
requirements. For the proposed CSB system, kitchen sink and dishwasher effluent could be
filtered at the source, and then added to the greywater treatment process to ensure disinfection.
Treated greywater will be used for subsurface irrigation.
Basis of Design and Precedent Projects
Chapter 16 of the 2013 California Plumbing Code (CPC) provides a pathway for the design and
installation of greywater systems for indoor reuse and subsurface drip irrigation. Additionally,
Chapter 17 of the California Code of Regulations provides guidance for cross-connections.
Both the City of Santa Monica Department of Building and Safety and the Los Angeles County
Environmental Health Department will concurrently review the proposed greywater treatment
and reuse system plans and specifications.
The CPC currently excludes kitchen waste from the definition of greywater, however, there are
examples of projects and regulations that define greywater to include kitchen sinks and
dishwashers throughout the west. Table 3 is a summary of states that classify kitchen sink
and/or dishwasher wastewater as greywater by code.
Table 3: Summary of states that classify kitchen wastewater as greywater
State
Washington
Oregon
Montana
Wyoming
Kitchen Sink
Wastewater




Dishwasher
Wastewater

Pretreatment of kitchen sinks and dishwashers at the source to remove fats, oils, and grease or
screen particles can effectively mitigate organic concerns that motivate this water to be
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classified as blackwater. California Assembly Bill 1738 introduced on February 1, 2016 by
assembly member Kevin McCarty, would establish the term “dark graywater” to define untreated
wastewater from kitchen sinks or dishwashers that has not been contaminated by any toilet
discharge, has not been affected by infectious, contaminated, or unhealthy bodily wastes, and
does not present a threat from contamination by unhealthful processing, manufacturing, or
operating wastes. The bill would require the California Department of Housing and Community
Development to adopt and submit for approval building standards for the construction,
installation, and alteration of dark greywater systems for indoor and outdoor uses.
As a precedent, the State of Washington requires that propriety treatment products used to treat
dark greywater systems meet the requirements of NSF40 certification for Residential
Wastewater Treatment Systems. The CPC requires that onsite treated greywater systems meet
the requirements of NSF350 certification for Onsite Residential and Commercial Water Reuse
Treatment, and there are currently numerous products that are both NSF40 and NSF350
certified.
There are multiple commercial projects that collect and treat building greywater, including
kitchen sink and dishwasher wastewater, for reuse. Each office in the Bullitt Center in Seattle,
WA includes a break room with kitchen sink and dishwasher. Washington State classifies these
types of waste as “dark greywater”, and it is treated with the “light greywater” in a recirculating
gravel filter. Treated greywater is then reused for irrigation. Another precedent for dark
greywater reuse is the CBF Brock Environmental Center, located in Virginia Beach, Virginia,
which utilizes a constructed wetland to treat all building greywater before it is returned to the
local aquifer.
Design and Operational Considerations
There are several design considerations to keep in mind for a viable, safe, and reliable
greywater treatment and reuse system. Building users must be educated on “best practices” for
the greywater system. Kitchen sinks should not be equipped with garbage disposals. In
compliance with CSM’s Zero Waste program, the CSB will provide compost bins for organic
waste in kitchens, which would contribute to mitigating the introduction of organics to the sinks
and dishwashers.
Regular maintenance of the greywater treatment and reuse system is essential to providing a
safe and reliable non-potable water supply for irrigation and foam flushing. Typical maintenance
activities include:
 Inspection and cleaning of the catch basin to prevent clogging
 Flushing of the lateral lines in the aerobic treatment unit to ensure even distribution
 Inspection of flow meters
 Inspection of pumps for proper function, cleaning when required
The CSB system designers will provide a comprehensive and customized Operations and
Maintenance Manual for the systems which will outline the frequency of maintenance activities
and describes each action in greater detail.
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3 Summary
The CSM goal to attain water self-sufficiency by 2020 highlights the immediate need for pilot
projects that capture and treat their own water. The CSB is a perfect opportunity to demonstrate
water self-sufficiency at building scale. The technologies to collect, store and treat wastewater
described within this report have all been implemented in other locations, however, they are
rarely supported by current regulations. The Bullitt Center provides an excellent example for not
only how to implement sustainable technologies, but how to collaborate with the regulatory
agencies to receive variances, exemptions and approvals.
The challenge before the CSM is to receive approvals for the proposed system so that future
projects can replicate some or all of the systems at the CSB. Multiple projects that conserve and
treat water will move the City closer to net zero water.
Table 4: Proposed CSB Systems and Regulatory Agencies
CSM Building
Official
Los Angeles
County
Department of
Public Health
Compost Toilets
(human waste
management)


Compost
biosolids
pasteurization



Compost
leachate
pasteurization



Rainwater to
potable


Dark greywater
as greywater


March 2016
California State
Division of
Drinking Water
California State
Regional Water
Quality Control
Board

EPA Safe
Drinking Water
Act


12
Acknowledgements
The City of Santa Monica would like to thank the following people that contributed to the
development of this Exhibit:
Pete Munoz, PE – Biohabitats, Inc.
Katie Bohren – Biohabitats, Inc.
Crystal Grinnell – Biohabitats, Inc.
Joel Cesare – City of Santa Monica: Office of Sustainability and the Environment
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