Hangtown Creek Water Reclamation Facility (HCWRF)
City of Placerville, California
The Hangtown Creek Water Reclamation Facility (HCWRF) is located in the Sierra Nevada
foothills of Northern California. The treatment plant capacity is 101 L/s (2.3 mgd) average dry
weather flow. Substantial improvements were required to comply with new waste discharge
requirements (including nutrient removal, year-round tertiary treatment, reduction of disinfection
byproducts, and effluent cooling) and a cease and desist order, sludge treatment regulations, to
address safety issues. A substantial increase in annual operation and maintenance (O&M) cost
was probable with the addition of the upgraded treatment processes and need to meet more
stringent effluent limits.
The design strategy included upgrading critical processes and replacing inefficient outdated
technology to improve treatment plant efficiency while mitigating increases in overall operation
O&M cost. Since the City service area is of limited size and the number of connections is not
growing, controlling O&M costs was a major concern of the City.
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Posted: May 20th, 2011 | Filed under: <50K, Waste Water Treatment | Tags: Improved Treatment Plant Efficiency, O&M Cost Savings, Plant Improvement | No Comments »
Toho Water Authority
Kissimmee, Florida
Toho Water Authority (TWA) provides water, wastewater and reclaimed water service to
approximately 85,000 customers in Kissimmee Florida. For the past three years the Utility has
been implementing an asset management program for their over $700 million dollars worth of
water, wastewater, and reclaimed water assets. During this program TWA has made significant
investments in asset management information systems including INFOR EAM Computer
Maintenance Management System (CMMS) and an ESRI Geographic Information System (GIS)
database. These two systems now contain the comprehensive asset inventory for the utility. A
built-in interface between the programs allows the CMMS and GIS to integrate and share
information.
Once the software implementation and inventory was complete, TWA wanted to obtain
additional physical, financial, and asset management attributes for their assets to support the
overall asset management program, which includes evaluating asset risk, measuring utility
performance and effectively planning for future renewal and replacement needs. The CMMS
software was configured to store the attribute data in January of 2008 after conducting interactive
workshops with staff to define the attributes. In August of 2008 a pilot project was implemented
to define the process to consistently collect and calculate the asset data including condition,
consequence of failure, risk, and replacement cost for all vertical assets in the utility. The pilot
area contained one water plant, one wastewater plant and 47 lift stations that fed the wastewater
plant. This paper will describe the methodology that was established to obtain and calculate the
data, the results of the data analysis, and uses for the data to further their asset management
program and overall decision making.
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Posted: May 20th, 2011 | Filed under: 50k-100k, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Capitol Planning, Improved Asset Management, Improved Operation and Maintenance | No Comments »
Bryan Wastewater Treatment Plant
Bryan, Ohio
Many communities are faced with considering a change in how their boisolids processing and disposal
programs will operate in the future. This discussion is coming about due to many biosolids processes that
were installed in the 1970s and 1980s under a different era of reuse and regulation and reaching the end of
their useful life.
To move forward there needs to be the establishment of objectives and goals that an evaluation is to be
built around for the future needs of biosolids processing for the owner/authority. The evaluation should
indentify the process that will be the most cost effective in capital and operation and maintenance costs. In
addition, with today’s concerns regarding climate change every evaluation should evaluate the carbon
footprint created by the various processes.
This is a case study of one evaluation done by the author that turned into a thermal dryer project that has
now been in operation for over six years.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Cost Effective Solution, Decreased Gas Consumption, Improved Plant Sustainability, Smaller Carbon Footprint, Solids reduction | No Comments »
Magna Water District
Magna, Utah
Aeration accounts for up to 60% of the total energy required for a typical activated sludge wastewater plant. A new process was developed that decreases aeration demand during secondary wastewater treatment. This process, called BIOBROx, blends oxidant-laden residuals with screened municipal wastewater followed by treatment in a fixed-bed (FXB) bioreactor. Pilot testing showed that the BIOBROx process was effective at removing perchlorate and nitrate from membrane residuals. Considerable biochemical oxygen demand (BOD) and suspended solids were also removed across the process. A 3.8-mgd BIOBROx demonstration facility is now operating at the Magna Water District. The BIOBROx train treats 1/3 to 1/2 of Magna’s total wastewater flow, uses no aeration, has an empty-bed contact time of 10 minutes, and has a footprint that is one-twentieth the size of the conventional secondary processes. Preliminary data show effluent that even under these conditions, BOD5 and TSS levels in the effluent from the BIOBROx process are similar to those in Magna’s conventional secondary treatment effluent.
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Posted: May 20th, 2011 | Filed under: <50K, Sanitary Sewer, Stormwater, Water Treatment | Tags: Cost Savings, Decreased Aeration Demand, Decreased Energy Consumption, Plant Sustainability, Smaller Carbon Footprint | No Comments »
Paulding County
Georgia
Before the recession, Metro Atlanta and its surrounding counties were one of the fastest growing
regions in the United States. In order to reduce the impact of treatment plant discharges on its
limited water supply and to offset water demands on potable water systems, they were
increasingly looking at water conservation and water reuse. Paulding County was one of those
fast-growing counties, consistently ranked between the 12th and 15th fastest growing counties in
the United States. Wastewater treatment facilities are among the most critical to support the
County’s rapid population increase. With tighter effluent limits on the way and a halt on surface
water discharge permits, the County had to look at alternative uses for the treated wastewater.
Several technologies were evaluated, and based on this evaluation, MBR technology became the
apparent leader. This paper provides an overview of the selection process, the procurement
process, and the performance of four MBR systems currently operating in Paulding County.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Improved Plant Efficiency, Plant Sustainability, Reduced Carbon Footprint, Water Reuse | No Comments »
District of Columbia Water and Sewer Authority (DC Water)
Washington, DC
Due to potential risks associated with transportation and handling of liquid chlorine, the District
of Columbia Water and Sewer Authority (DC Water), switched to the use of liquid sodium
hypochlorite as the disinfecting agent at the Blue Plains Advanced Wastewater Treatment Plant
(AWTP). The escalating cost of bulk purchased sodium hypochlorite prompted DC Water to
commission a study to evaluate disinfection alternatives that: 1) are compatible with existing
treatment processes; 2) meet all plant effluent disinfection requirements; and 3) reduce life cycle
costs of disinfection.
The study involved a detailed technical, economic and non-economic evaluation of the feasibility
of constructing and operating an onsite sodium hypochlorite generation facility in lieu of bulk
purchase. Economic analyses included capital and O&M costs, life cycle costs over a 30-year
time horizon, and sensitivity of price of bulk sodium hypochlorite and salt, electric power cost,
debt service on life cycle costs.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Capital Savings, Improved Plant Reliability, O&M Cost Savings | No Comments »
Orange County Sanitation District (OCSD)
Orange County, California
The purpose of this paper is to help project managers in public agencies understand the reasons
for resistance to change and provide steps to overcome or minimize the resistance. These are
challenging times for all public agencies so there is a need to be wise stewards of public
resources. An increase in efficiency may require reorganizing departments, reallocating
resources and realigning staff roles and responsibilities and managing projects differently. These
all require change and growth from all levels of employees in an organization. Reducing the
resistance to change requires strong leadership qualities combined with proper project
management skills. If these combined skills are incorporated into projects that implement
change, they will be successful and can result in significant cost savings. The Orange County
Sanitation District (OCSD) has undergone many of the aforementioned changes in the past
couple of years and continues its austerity through efficiency while completing all tasks.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment | Tags: Cost Savings, Improved Plant Efficiency, Project Management | No Comments »
San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP)
San Jose, California
In this study, Nocardia foam control using a combination of polymer addition and solids
retention time (SRT) reduction was investigated at the San Jose/Santa Clara Water Pollution
Control Plant (SJ/SC WPCP). A three-week continuous polymer addition at increased dosing
rates of 0.35 mg/l, 0.5 mg/l and 0.75 mg/l reduced Nocardia foam coverage from 100% to less
than 5%. But, foam accumulation returned to 95% coverage when polymer dosing was stopped
for a week. It only took a week to eliminate Nocardia foam from the aeration tanks when 0.5
mg/l polymer addition was accompanied by SRT reduction from eleven days to four days. A
potential effluent ammonia permit violation associated with SRT reduction was avoided by
aerating the anoxic compartment of the aeration tanks and converting the step-feed biological
process to plug flow mode. Except an increase in secondary effluent solids concentrations during
plug flow operations, polymer addition to the return activated sludge (RAS) and Nocardia
wasting to the digesters via dissolved air floatation did not cause foaming in the digesters nor
was it detrimental to effluent filtration.
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Posted: May 20th, 2011 | Filed under: >1M, Waste Water Treatment | Tags: Improved Plant Effluent, Improved Plant Operations, Nocardia Foam Control, Reduced Solids Retention Time | No Comments »
Point Loma WWTP
San Diego, California
San Diego’s Point Loma WWTP is a 160 MGD (240 MGD permitted), 100% advanced primary
treatment plant that has historically used iron salts for collection system sulfide control and
chemically enhanced primary treatment. Beginning in 2006, a PRI-SC® (Peroxide Regenerated
Iron – Sulfide Control) program was implemented by adding H2O2 at the intermediate pump
station PS2 (in place of the FeCl3), and again to the plant influent (ahead of FeCl3 addition for
CEPT). The application of PRI-SC® in the Point Loma system was designed to provide at least
$685/day in cost savings, to be achieved through reduced ferric chloride use at PS2 and Point
Loma, while improving sulfide control and CEPT performance. Since integrating the PRI-SC®
program full-time in 2008, SDMWD is realizing savings of approximately $4,700 per day
(~$1.72 million/yr) compared to the 2007 baseline iron salts program. At the same time, both
sulfide control and CEPT performance has improved. The cost savings were helped by the
hedging aspect of the PRI-SC® program – iron salt price volatility in 2008 and 2009 was
upwards of 45%. The PRI program has reduced the total iron salt use from the 2007 baseline rate
of 32.5 dry tons per day to approximately 19.3 dry tons per day in 2009, with the core savings
coming from an overall reduction in ferric chloride use at PS2 and the treatment plant (Table 1).
Significantly, ferric chloride use at PS2 was eliminated and, for CEPT, reduced from 24 mg/L to
10 mg/L (16.6 to 6.8 dry tons per day) with no loss in performance. In addition, total sulfide
removal has improved over baseline levels, and average CEPT performance exceeds the permit
levels at 89% for TSS and 65% for BOD, and effluent water quality has improved (with 60% less
spent iron (as FeS) present in the ocean discharge). For the most part, digester biogas H2S levels
were maintained below the permit requirement of < 40 ppm, but required approximately twice
the baseline FeCl2 feed rate. Even so, the overall program has maintained the stated savings
benefit.
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Posted: May 20th, 2011 | Filed under: >1M, Waste Water Treatment | Tags: Chemically Enhanced Primary Treatment, Cost Savings, Improved Operational Efficiency, Improved Plant Effluent, Improved Plant Performance, Sulfide Control | No Comments »
Saco Wastewater Treatment Plant
Saco, Maine
The use of novel CSO control, treatment and disinfection systems based on advanced vortex technologies
including Vortex Flow Controls (VFC) and Hydrodynamic Vortex Separator (HDVS) that enable,
Screening, Grit Removal, Sedimentation and Disinfection to be accomplished in one vessel is described.
The application of the technologies at the Saco Wastewater Treatment Plant involves a new generation of
HDVS and vortex flow controls that regulate wet-weather flows to control maximum flows to the existing
wastewater treatment plant to avoid hydraulic overloading and the diversion of excess combined sewage
flows to the new CSO treatment facility.
The wet-weather treatment facility utilizes an advanced HDVS that incorporates a non-powered, selfactivating
and self-cleansing CSO floatables screening system; with the captured pollutants comprising
sewer debris and solids including sediments, settleable organic solids and floatables, being returned to the
headworks at the treatment plant and the clarified, screened and disinfected overflow being discharged to
the receiving environment (Saco River), after de-chlorination.
The ability to perform several essential unit processes (i.e. Screening, Grit Removal, Sedimentation and
Disinfection) all in one vessel resulted in significant savings in the overall project scheme costs on
account of the more compact design of the advanced HDVS system coupled with the elimination of
additional tanks and vessels that would have been required with the conventional approach. Analytical
results from post-construction compliance monitoring have confirmed the efficacy of the advanced vortex
technologies.
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Posted: May 20th, 2011 | Filed under: <50K, Stormwater, Waste Water Treatment | Tags: Cost Savings, Improved Disinfection, Improved Plant Efficiency, Improved Solids Removal, Optimal CSO Control | No Comments »