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Wastewater
Treatment & Disposal
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To
responsibly operate and maintain the wastewater
treatment and disposal system of the North
San Mateo County Sanitation District in a
manner that provides current and future customers
with safe, efficient and cost effective wastewater
treatment services while protecting the environment
from water pollution.
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treatment plant is on the site of the
very first treatment system for the
area. A large septic tank served the
early population - which grew drastically
as survivors of the 1906 San Francisco
earthquake and fire sought refuge in
Daly City. In 1907, the Spring Valley
Water Company, fearing pollution of
its water supply, permitted the septic
tank overflow to be diverted to the
Vista Grande Tunnel for disposal to
the Pacific Ocean. The Vista Grande
Tunnel was built in 1895 to handle storm
water overflow from Lake Merced. The
brick, egg-shaped tunnel is still used
today to transport treated wastewater
from the City's effluent pipeline to
the ocean outfall at Thornton Beach.
The
area's population took another sharp
jump after World War II, as returning
veterans bought homes for their families
in Broadmoor Village and Westlake subdivisions.
To serve the wastewater collection and
treatment needs of this growing area,
the San Mateo County Board of Supervisors
created the North San Mateo County Sanitation
District on January 16, 1951. In 1953,
voters approved a $600,000 bond issue
to finance construction of a primary
wastewater treatment plant at the southerly
end of Westlake Park. The plant went
into operation in August of 1955, serving
a population of 30,000.
Artichoke fields and hog ranches continued
to give way to houses as St. Francis
Heights and Serramonte were completed.
In 1975, with funding from the Clean
Water Act Grant Program, the plant facilities
were upgraded to full secondary treatment.
The secondary plant utilized the UNOX
pure oxygen, activated sludge process.
On July 1, 1985, the North San Mateo
County Sanitation District became a
subsidiary district of the City of Daly
City. At that time, the plant was nearing
its treatment capacity. As interim measures,
the City formalized a Water Conservation
Program and instituted a moratorium
on new sewer connections. Meanwhile,
planning began for Daly City's most
ambitious public works project ever
undertaken.
The
treatment plant experiences very high
morning and evening peak flows. This
is a characteristc common to "commuter
communities", but in Daly City the peaks
are abnormally high - nearly three times
greater than the average daily flows.
In 1989 the plant was expanded to equalize
the peak flows and provide additional
capacity. |
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The
expansion featured a unique underground
primary treatment and flow equalization
system. The $14.7 million underground
facilities increase the plant's secondary
capacity from 8 to 10.3 million gallons
per day. The facilities were designed
for underground construction to preserve
the residential and recreational setting
of the plant site. An existing softball
park was temporarily removed during
construction. The plant expansion and
related landscaping, roadways and lighting,
were financed entirely by District-backed
Certificates of Participation.
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City's collection, treatment and disposal
systems serve the majority of the residents
of Daly City, along with the Broadmoor
Village, a portion of the Town of Colma,
the Westborough County Water District
in South San Francisco, and the San
Francisco County jail in San Bruno.
Daly
City's operation of its wastewater system
has been widely recognized for its community
involvement, dedication to water quality
issues, and efficient operation. The
City was awarded "Wastewater Treatment
Plant of the Year" from the California
Water Pollution Control Association,
"Award for Excellence in Collection
System Operation and Maintenance" from
the United States Environmental Protection
Agency, as well as awards to individual
staff members such as "Treatment Plant
Operator of the Year, "Collection System
Person of the Year" and "Plant Maintenance
Person of the Year". |
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Annual
Discharge Monitoring Report |
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NORTH
SAN MATEO COUNTY SANITATION DISTRICT DISCHARGE
MONITORING REPORT SUMMARY FOR 1999 |
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GRAPHIC
AND TABULAR SUMMARIES |
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Annual
Discharge Monitoring Report for 1999 |
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Biosolids Monitoring Report |
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NOTICE
AND NECESSARY INFORMATION (NANI)
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Regulatory
and Policy Background |
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In
1972, under the authority of Public Law 92-500,
the Federal Water Pollution Control Act, EPA
created the NPDES. This was intended to control
discharges to the Nation's waters from industrial,
commercial, and municipal point sources; these
discharges presented a threat to water quality
and public health. Initial efforts focused
on traditional pollutant discharges from industrial
manufacturing processes and municipal Wastewater
Treatment Plants (WWTP).
Later amended to become the Clean Water Act
(CWA), this law provides broad authority for
EPA or States (authorized by EPA) to issue
NPDES permits. Specific reporting requirements
are established in the permits to require
monitoring and reporting of discharges. The
CWA establishes two types of standards for
conditions in NPDES permits: technology-based
standards and water quality-based standards.
These standards are used to develop effluent
limitations and special conditions in NPDES
permits. Numeric effluent limitations establish
pollutant concentration limits for effluents
at the point of discharge. Section 402(a)(1)
authorizes the inclusion of other types of
conditions that are determined to be necessary,
known as special conditions, in NPDES permits.
Special conditions can include requirements
for best management practices (BMPs) to control
Wet Weather Flows (WWF).
Since the implementation of the CWA requirements,
EPA has begun to address nontraditional sources
of pollution, such as those that result from
WWF. The NPDES program currently requires
permits for point sources, but not for non-point
sources (NPS).
Pollutants in WWF discharges from many sources
remain largely uncontrolled. The EPA in both
its 1992 National Water Quality Inventory
(EPA, 1994a) and its 1995 Report to Congress
(EPA, 1995a) cited pollution from WWF as the
leading cause of water-quality impairment.
WWF from both point and non-point sources
is one of the largest remaining threats to
water quality, aquatic life, and human health
that exists today. The National Research Council
(1992) concluded that correction of NPS pollution
problems is a major priority to surface water
protection and should be implemented as part
of a large-scale aquatic ecosystem program.
In its National Agenda for the Future, issued
on December 30, 1994, two priority areas were
cited by EPA in the water program: - protect
public health by ensuring that drinking water
is safe - protect the environment by improving
WWF controls EPA reiterated this in 1996 in
the updated "National Water Program Agenda
for the Future: 1996-1997".
Over the past two decades, local, regional,
and national-scale research programs have
shown that pollutants discharged from municipal
separate storm sewer systems are among the
principal causes of water quality problems
in most urban areas. Recognizing this, Congress
and USEPA set forth legislation and regulations
(respective) that have required public works
managers in most sizeable urban areas to focus
attention on their storm water collection
and conveyance systems. The regulations were
intended to get senior management personnel
engaged in efforts to consider the following:
- What
are the physical characteristics of our
storm water system?
- Where
does it discharge to the local receiving
waters?
- What
land uses and activities are served by
the system (and contribute pollutants)?
- What
degree of control do we have over those
who contribute pollutants?
- What
concentrations and annual loads of pollutants
are discharged with our storm water?
- What
do we presently do to minimize those pollutants
and their resultant impacts?
For
most sizeable municipal public works departments
and flood control agencies, the past several
of years' efforts to respond to NPDES permitting
requirements have been challenging and illuminating;
but also frustrating. Most applicants learned
things about their systems that will help
them be better managers in the future. Most
of these applicants are now facing the lack
of practical ways to effectively conceptualize
and manage large, complex urban watersheds.
To do so will require managers to collect
and consider large amounts of diverse information
on a continuing basis. |
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Meeting
Clean Water Standards |
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The
treated wastewater (effluent) that our
Treatment Plant discharges into the
Ocean is subject to stringent water
quality standards specified in our discharge
permit. This permit-part of a program
called the National Pollutant Discharge
Elimination System, or NPDES-is issued
by the San Francisco Regional Water
Quality Control Board. Permits are usually
renewed every five years.
Specific discharge standards are determined
by the Regional Board on a case-by-case
basis and often differ from one wastewater
treatment plant to another. For example,
a treatment plant that discharges into
the Bay or river will have more stringent
standards than NSMCSD, which discharges
into the ocean.
NPDES permits specify maximum permissible
levels for various technical measurements,
including the quantity of effluent discharged
in wet and dry weather (flow rates),
plus Carbonaceous Biochemical Oxygen
Demand; Grease and Oil; Suspended Solids;
Settleable Solids; Turbidity and Acute
Toxicity.
Although no specific discharge limitations
have been set, NSMCSD's discharge permit
also requires regular monitoring of
eighty-three other water quality standards.
In addition the discharge permit requires
monitoring at the point of discharge
into the Ocean. Separate permits address
disposal of the solids removed from
wastewater and the quality of stormwater
runoff.
For more information on NSMCSD's discharge
permit, please contact: Cynthia Royer
or Dennis Baker at (650) 991-8200 or
email them at croyer@dalycity.org
or dbaker@dalycity.org
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NPDES |
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Wastewater
NPDES Permit NO. CA0037737 |
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Attachments:
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Contingency
Plan - Regional Water Board Resolution
No. 74-10 |
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Self-monitoring
Program |
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Part
A, Dated August 1993 |
| Part
B, Dated February 16, 2000 |
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Stormwater |
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City
NPDES Stormwater Permit |
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Air |
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Keeping
Daly City's Air Clean
In the San Mateo County area, the Bay
Area Air Quality Management District
(BAAQMD) regulates emissions of smog-producing
chemicals. Other regulatory agencies
include the California Air Resources
Board and the U.S. Environmental Protection
Agency. These agencies establish limits
on smog-related chemicals produced by
a variety of combustion sources. NSMCSD's
principal combustion sources are:
- Digester
gas flares and boilers used in wastewater
treatment processes, and
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Diesel-powered generators and pumps
that keep critical water and wastewater
pumping stations operating during
extended power failures, ensuring
uninterrupted service to our customers.
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NSMCSD
is committed to protecting our environment.
We endeavor to recycle and reuse the treated
by-products of our plant, namely, treated
wastewater effluent and biosolids. California's
limited water supply will pose greater challenges
for our future, and the NSMCSD, in cooperation
with others, will look for new ways to reuse
water. The NSMCSD reclamation program began
in the late 1980s in response to the drought
and continues today to conserve a precious
resource. We also make sure that our biosolids
are put to good use for safe land application
and soil amendment. Reuse completes the cycle
that leads to a sustainable future. |
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Recycled Water |
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Water
Recycling - a responsible solution to the
growing demand for water
Recycled water is a smart alternative water
supply source for the Daly City area due to
its limited groundwater supply and increasing
population. By using recycled water for non-potable
(non-drinkable) uses such as irrigation, precious
drinking water supplies can be conserved.
Since the mid eighty's the NSMCSD has been
installing recycled water pipes around the
City when water or sewer projects are constructed.
Our Water Irrigates
Nearby Landscapes
Currently, our recycled water is used to irrigate
landscaped medians in the Westlake area. A
study is being conducted to use our recycled
water to maintain the level of Lake Merced
and eliminate the use of potable groundwater
to accomplish optimum level. It is also being
used for various uses at the wastewater treatment
plant. Plainly marked purple pipelines, completely
separate from drinking water systems, deliver
the water to use sites. Water recycling is
a safe and proven practice. For many years,
recycled water has been safely used for landscape
irrigation purposes throughout California
and the world saving several million-acre
feet of precious potable water for other uses.
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Biosolids |
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The
NSMCSD's treatment process produces approximately
6 tons of dry sludge per day, all of which
is recycled. During the rainy season the biosolids
are used as daily cover at Redwood Landfill
in Novato. During the spring and summer months
it is used as a soil amendment for non-edible
food crops in Solono County. |
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Date
Approved
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Ordinance
Number
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Old
Rate |
%
Increase
(Decrease)
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New
Rate |
Minimum
Charge
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7/12/99
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84
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$ 2.90 |
5.0
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$ 3.05 |
$ 36.96 |
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7/14/97
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83
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$ 2.83 |
2.5
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$ 2.90 |
$ 36.96 |
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6/12/95
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82
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$ 2.75 |
3.0
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$ 2.83 |
$ 36.96 |
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6/12/93
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81
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$ 2.95 |
(9.0)
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$ 2.75 |
$ 28.00 |
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6/13/92
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76
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$ 2.40 |
22.9
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$ 2.95 |
$ 28.00 |
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5/1/91
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75
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$ 1.96 |
22.0
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$ 2.40 |
$ 28.00 |
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6/26/89
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73
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$ 1.66 |
18.1
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$ 1.96 |
$ 25.50 |
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6/27/88
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71
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$ 1.54 |
7.8
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$ 1.66 |
$ 25.22 |
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7/13/87
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70
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$ 1.48 |
4.1
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$ 1.54 |
$ 23.40 |
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6/23/86
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65
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$ 1.31 |
3.0
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$ 1.48 |
$ 22.50 |
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5/25/85
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61
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$ 1.28 |
2.3
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$ 1.31 |
$ 18.00 |
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5/18/84
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59
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$ 1.25 |
2.4
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$ 1.28 |
$ 18.00 |
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5/23/83
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57
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$ 1.20 |
4.2
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$ 1.25 |
$ 18.00 |
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5/25/82
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54
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$ 1.20 |
$ 18.00 |
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