Download Marshall Community Wastewater Program

Excellence in Environmental Health Award
2016
Marshall Community Wastewater Program
A Community Approach to Solving Old and Failing Septic Systems
Submitted by
Marin County Environmental Health Services
Introduction
Marin County Environmental Health Services (EHS) recently completed a five year program to
design, permit, and construct Phase 2 of the Marshall Community Wastewater System. This
milestone culminates over fourteen years of work to mitigate old and failing septic systems on
small lots adjacent to commercial shellfish beds in Tomales Bay. This innovative and community
based approach is a step beyond the traditional land use duties to manage, permit, and inspect
individual on-site waste treatment systems (OWTS.)
This new role represents an alternative approach for environmental health professional to
address widespread problems of failing septic systems in rural areas. It also represents a new
opportunity to develop problem solving skills, to help a community to come up with a solution,
and to carry a project forward from concept to operation.
Marin County EHS has an ongoing role to operate and maintain the Marshall Community
Wastewater System. This includes ensuring compliance with all operating permits, making sure
emergency procedures are in place, and implementing the Sewer System Management Plan.
Background
Located along the west coast of Marin County, Tomales Bay (Bay) is a long narrow inlet of the
Pacific Ocean. The Bay is a valuable and aesthetic resource for recreation, shellfish, and
wildlife. The Bay provides habitat for several threatened or endangered species, including Coho
salmon and steelhead, and is safe harbor for the migration, feeding, and resting areas of
waterfowl and marine mammals. The Bay supports seven commercial shellfish operations, as
well as popular recreational activities such as boating, kayaking, and fishing.
In 1995-1996, the San Francisco Bay Regional Water Quality Control Board (RWQCB)
conducted an Investigation of Pollution Sources Impacting Shellfish Growing Areas of Tomales
Bay. Of the sources of pathogens, human waste carries the highest risk of viral contamination.
Faulty sewage and on-site septic systems from near-shore homes along the Bay were identified
as the most likely sources of human pathogens.
A call to action came in 1998 when a norovirus outbreak affected 171 people who consumed
shellfish harvested from the Bay. Contamination was traced to human fecal origin. It was
determined that the two most likely causes were substandard and potentially failing septic
systems or toilet waste discharge from a boat.
In 2005, the RWQCB designated the Bay as impaired for pathogens and issued the Pathogens
in Tomales Bay Watershed Total Maximum Daily Load (TMDL.) This plan calls upon Marin
County EHS to asses and oversee the repair of OWTS, particularly within 100 feet of Tomales
Bay.
The rural community of Marshall runs along the northeastern shoreline of Tomales Bay and is
characterize by small single-family residences and a few businesses built decades ago with
septic systems reflecting the minimal design requirements of that time. Some of the septic
systems had zero setbacks to the bay and discharged effluent into fill or old oyster shells. An
evaluation of individual septic systems revealed that 40% of the existing systems were either
failing or only functioning marginally. Based on these results and the TMDL, older systems
within 100 feet of open water were identified as the highest priority for remedial action.
Given the small lots and proximity to the Bay, EHS hired engineering consultants and worked
with the community to design a system that would provide a better, long-term solution that
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would improve and protect coastal waters. In 2007, EHS formed a special assessment district
along the northern shoreline of Marshall and began construction of the first phase of a
community-scale wastewater collection, treatment, and land-discharge system. Phase 1
involved the replacement or upgrade of individual septic tanks with submersible septic tank
effluent pumps (STEP), construction of a mile-long pressure sewer line, and installation of a
common leachfield on a 6-acre site purchased by the County. At the community leachfield site,
a pump house was constructed for the main effluent lift station, which transmits wastewater
uphill to a 2,000-gallon dosing tank feeding two duplex dosing siphons that disperse wastewater
to alternating portions of leachfield. This work was completed in July 2008 and serves 32.5
residential units, the post office, and two small commercial connections. While the initial design
flow was for 9,120 gallons per day, the leachfield was designed with provisions to expand and
accommodate a Phase 2 area.
The direct cost of Phase 1 was approximately $2.01 million dollars. Marin County EHS secured
this funding through a collaborative effort with the San Francisco Regional Water Quality Control
Board ($702,500), the U.S. Environmental Protection Agency ($374,000), Marin County
($237,174), and property owners ($700,800.)
Innovative Solution
In 2011, building on the success and lessons learned in Phase 1, EHS embarked on Phase 2
and annexed 22 more residential units and a local restaurant located along the southern
shoreline of Marshall to the wastewater assessment district. Over the next two years, staff wrote
grants, hired engineers to design the system, applied for financing, and held an election of the
property owners to secure funding for the design and construction of additional wastewater
facility improvements. The result, the State Water Resources Control Board provided a
$750,000 grant from the Federal Clean Water Act Section 319(h) and the County secured
$450,000 with a 3.6% bond over a 20-year term to finance the property owners’ portion of this
project.
Once financing was lined up, the County went out to bid to select a construction contractor and
hired the design engineers to manage construction. Construction began in April 2015. As in
Phase 1, individual septic tanks were replaced or made watertight and retrofitted to current
standards. Controls and STEP units were installed at each tank to regulate the flow of septic
tank effluent into the force main. Approximately 4,500 feet of 2 and 3-inch diameter effluent
forced main was installed for the full length of the service area along State Route 1 to the
leachfield area.
A recirculating textile-media filter system was installed at the community treatment site. Now,
effluent from Phase 1 and 2 are mixed and receive secondary treatment. The resulting treated
effluent, which is greatly reduced in bacteria, BOD, and nitrogen, is pumped from the main lift
station to the existing dosing tank at the high point of the site for dispersal to the leachfield. An
additional 600 lineal feet of trench was added to the initial leachfield, expanding the available
soil infiltration area by approximately 25 percent. Phase 2 construction was completed on time
and within budget in January 2016.
The system incorporates several safeguards. Check valves and air release lines are
incorporated into the wastewater collection pipeline. The system has two emergency
generators: 1) the main generator for the pretreatment and leachfield operations, and 2) a
portable generator housed on a trailer that can power individual STEP units in the event of a
prolonged power failure. An additional 5,000-gallon holding tank for emergency storage capacity
is provided at the lift station. The system incorporates telemetry equipment and alarms, which
are monitored by the design engineers and the operation and maintenance contractor.
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The ongoing role of EHS is to ensure the proper operation and maintenance of the system.
Through a formal request for proposals, EHS selected a qualified wastewater management
company with 24-hour response capabilities to manage the system. The County oversees the
contractor’s monitoring and reporting of the system in compliance with the Monitoring and
Reporting Program (MRP) required by the RWQCB. This monitoring will provide an ongoing
evaluation to ensure target performance measures are met. Marin County EHS is also
responsible for ensuring individual systems are inspected each year and notifying property
owners when their tanks need to be pumped.
The total cost for constructing Phase 1 and 2 was $3.24 million. This does not include the
annual operation and maintenance cost paid by the property owners, which is estimated to be
$64,500 for the current year.
Outcome and Achievements
The overarching goal of the project was to protect and improve the bacteriological quality of
Tomales Bay by reducing human pathogen sources that contributed to the Bay’s designation as
a 303(d) impaired water body. The target was the removal of pollution from older on-site septic
systems with inadequate setbacks to the Bay. The sustained improvements and successful
performance of the project is measured several ways:
Pollutant Load Reduction
A key measure of success is the reduced pollution load achieved by decommissioning old and
failing OWTS. Overall, the wastewater stream from 54.5 residential units and three businesses
were connected to the community system. With that, property owners received financing for the
community portion of the upgrade, efficient and timely construction of the new system, and
consistent on-going maintenance and compliance that would not have been otherwise available
to them.
Construction of the Phase 2 effectively removes the potential of approximately 5,640
gallons per day of septic tank effluent from disposal along the shoreline of Tomales Bay.
Moreover, the combined effluent from both phases now passes through secondary
treatment and is discharged in the expanded community leachfield system.
Additionally, two of the homes within the overall assessment district boundary that opted not to
connect were inspected, repaired, and issued operating permits to verify ongoing compliance of
their systems. A third residence with limited use has been placed on a routine monitoring
program to ensure compliance. With that, the target of 100% reduction in wastewater flow and
100% reduction in human pathogens previously discharged to Tomales Bay from properties
within the project service area was achieved.
Monitoring and Reporting
The program’s operation and performance will be verified pursuant to the system’s new 2015
MRP. Key measurement tools include the following:
1. Wastewater flow treated by the community wastewater facility - Wastewater flows are
being monitored and evaluated on an ongoing basis. This verifies the system is working
within its design capacity 14,640 gallons per day.
2. Groundwater monitoring wells located between the community leachfield and Tomales
Bay – Monitoring for groundwater level, nitrate as nitrogen, and fecal coliform are being
measured as part of the ongoing operation and maintenance of the system and is being
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evaluated for consistency with the system’s MRP. Phase 1 has consistently performed in
compliance with the first MRP monitoring requirements. Based on the initial levels of
nitrogen and bacteria in the monitoring wells, the expanded system is working properly.
Habitat Restoration Performance Measures
The Tomales Bay TMDL calls for no human waste (raw sewage or inadequately treated waste)
to be discharged to Tomales Bay or its tributaries. The numeric targets in the TMDL are based
on fecal coliform bacteria concentrations that protect shellfish harvesting and recreational uses.
The coliform bacteria targets, in combination with the human waste discharge prohibitions and
the closure targets for shellfish harvesting, are the basis for the TMDL and load allocations. The
Marshall project will help achieve these targets.
California Department of Public Health issues annual sanitary surveys for shellfish growing
areas in Tomales Bay. Ongoing monitoring by the State and shellfish growers will track
improvements over time. Since the construction of Phase 1, no high levels of pathogens have
been attributed to the community served by the Marshall System.
Marin County EHS tests beaches in the Tomales Bay for compliance with recreational water
quality standards. Samples at the closest beaches (Miller Park and Millerton Point) typically
meet recreational standards. The occasional water quality advisory for Millerton Point is
attributed to a creek outflow at the sample site that does not drain from the Marshall community.
Successful Involvement of People
The realization of this program relied on the cooperative involvement of many organizations and
people – State and Regional Water Quality Control Boards, Marin County, Coastal Commission,
and the community. Property owner education and awareness were essential to the success of
this program. Throughout Phase 2, property owners were fully engaged – from voting to join the
assessment district, signing access easements, arranging repairs to their household plumbing
and electrical systems to accommodate the new STEP system, and obtaining abandonment
permits for their old septic tanks.
Marin County EHS established an ongoing partnership with property owners. Numerous
meetings were held throughout the project and will continue on an as-needed basis. With a
newly managed community system, property owners will continue to be actively involved in the
ongoing operation and maintenance of their on-site system. With close communication, property
owners, residents, and property managers are learning the proper attention, use, and care of
septic systems. As a community, they are learning what to do when a warning alarm goes off,
what happens when renters ignore an alarm, and appropriate action to take when the power is
out.
Expanded Role for Environmental Health
The construction of the expanded community system required many steps and key planning
milestones, which include the following:
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Forming an Assessment District
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Grant writing and grant management
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Hiring and managing consultants to prepare design plans, oversee construction, prepare
the final as-built drawings, and update the operation and maintenance (O&M) manual.
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Preparing and notarizing access easements from all property owners
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Submit permit applications and receive public agency approvals:
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California Coastal Commission Coastal Permit,
Caltrans Encroachment Permit,
SWRCB Stormwater Pollution Prevention Plan and Sanitary Sewer Management
Plan (SSMP),
EHS community septic permit and individual permits and inspections to abandon
old septic tanks,
RWQCB issued the Notice of Applicability and MRP

Special archeological fieldwork
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Select and manage the ongoing operation and maintenance contractor
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Verify ongoing compliance with each of the system’s operating permits, e.g. community
septic permit, MRP, and SSMP
Summary
A community-based approach to septic issues offers an alternative approach to the County’s
traditional management of OWTS. This innovative program underscores the growing role and
expanding opportunities for environmental health professionals.
The success and experience gained from the Marshall project are being shared with other areas
in Marin County seeking a community-wide approach to a mutual problem of aging and failing
OWTS. Marin County EHS has taken the lead once again and is currently working with a
community group in semi-rural San Geronimo Valley. This community of approximately 300
single-family residences is faced with similar problems of failing septic systems adjacent to
waterways draining into Lagunitas Creek, a designated impaired water body for pathogens. A
feasibility study sponsored by EHS in 2014 identified a community collection system with a
tertiary treatment, ponding, and recycling to a nearby golf course as a preferred remediation for
150 properties. We recently received grant funding from the SWRCB to evaluate this option for
300 homes. With funding from the County, Marin Municipal Water District, and property owners,
we will soon begin preparing the environmental impact report on this approach.
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Marshall Community Wastewater Program - Service Area
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