Philadelphia Water Department (PWD)
Philadelphia, Pennsylvania
Because of issues with plant efficiency and the inconsistency of year round performance, the
Philadelphia Water Department (PWD) identified areas where they would like to see the
performance of their DAFT systems improve. The objective was to investigate factors that
would improve the DAFT’s performance, particularly by increasing float solids concentrations
and reducing the suspended solids loads returned to the treatment plants via the underflow. An
evaluation of existing plant operational data showed that in most cases the parameter that most
influences float solids concentration was the SVI and the parameter that most influences the
underflow concentration was the air/solids ratio.
Because of the importance of the air/solids ratio in maintaining low underflow solids
concentrations, an on site evaluation of the efficiency of the air saturation systems was
performed. Representative tanks were tested using a saturator monitoring unit which isolates a
small portion of the pressurized flow from the saturation tank and measures the mass of air
precipitated from the volume of flow. The mass of the precipitated air volume was compared to
the theoretical mass of air dissolved under the same ambient conditions to compute efficiency. A
well designed saturation system should provide an efficiency of approximately 88-percent. The
measured efficiencies ranged from approximately 48 to 78 percent. There are a number of
actions that could be taken to improve efficiencies including nitrogen purging from the saturator
headspace, verification that impingement plates are adequately designed and fully intact, and
adequately sized nozzles within the saturators. Improving the A/S ratios would reduce underflow
solids thereby reducing the return solids loads and overall operating costs at the plants.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Improved Plant Efficiency, Improved Plant Performance, Increased Float Solids Concentration, Operating Savings, Optimized Air/Solids Ratio, Reduced Suspended Solids | No Comments »
Sacramento Area Sewer District
Sacramento, California
The Central Trunk Sewer is an eight mile pipeline that conveys both residential and industrial
sewage for Sacramento County. Constructed in the 1960’s of unlined reinforced concrete, the
pipeline ranges from 33-inches to 60-inches in diameter and is located deep under major roads,
residential backyards, creeks, protected wetlands, and a state highway. Nearly 50 years of
corrosion has severely deteriorated the pipeline and restoring the structural stability of the
pipeline in a cost effective manner with minimal decrease in capacity and distribution to the
community became the primary goals for the Sacramento Area Sewer District (SASD). To meet
these goals SASD and their design consultant West Yost Associates (West Yost) chose cured-inplace
pipe (CIPP) to rehabilitate the entire eight mile pipeline alignment.
Throughout construction several lessons have been learned from this large CIPP project. This
paper will discuss some of the lessons learned as well as considerations for owners and designers
regarding quality control and quality assurance of liner samples, bypass vs. plugging sewer
flows, environmental mitigation monitoring and reporting program, public outreach, air quality
regulations, construction noise mitigation, and debris estimating.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: CIPP Rehabilitation, Corrosion Prevention, Environmental Impact, Improved Customer Relations, Improved Sewer Rehabilitation, Increased Sewer Life, Minimized Community Disruption, Noise Mitigation, Pipe Construction Alternative, Reduced Inflow and Infiltration | No Comments »
Orange County Sanitation District (OCSD)
Orange County, California
Wastewater from the coastal areas of the City of Huntington Beach are conveyed to the Orange
County Sanitation District’s Treatment Plant No. 2 through a 1350 mm/1800 mm/2100mm PVC
(Polyvinyl Chloride) lined RCP (Reinforced Concrete Pipe)sewer. The sewer was constructed in
the early 1980′s to service an area that included residential development at the north end that did
not occur due to overwhelming environmental issues. Since then, the sewer has conveyed
substantially lower flows and the portion of the sewer not lined with PVC has been exposed to
corrosive sewer gases and has corroded.
This project included a full evaluation of the condition of the sewer and looked at alternatives for
repair. Ultimately, the course of action included a unique solution that allowed the line to be
rehabilitated with a minimum of impact and disturbance to surface improvements including hotel
resorts and beach activities particularly during the summer.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: CIPP Rehabilitation, Corrosion Prevention, Environmental Impact, Improved Customer Relations, Improved Sewer Rehabilitation, Increased Sewer Life, Minimized Community Disruption, Noise Mitigation, Pipe Construction Alternative, Reduced Inflow and Infiltration | No Comments »
City of Columbus Department of Public Utilities (DPU)
Columbus, Ohio
The water utility industry is facing significant challenges in these uncertain times. Many of these
business drivers have been around for some time but many are new or emerging and
now threaten business as usual and even the viability of utilities. Many water and wastewater
utilities have started asset management (AM) programs to answer these challenges; some have
been on the journey for a number of years. Large infrastructure deficits requiring huge amounts
of money needed for infrastructure replacement have caused many to rush into AM programs,
only to find that they have not realized the benefits they thought they would achieve and needed.
Some AM programs only affect a small portion of staff and staff functions that do not directly
impact the overall operation of the utility. Others have adopted comprehensive AM programs,
but are stuck in visioning and strategy or in implementation of AM areas that have limited
(obvious) benefits.
AM best practices include a broad range of activities, but the key aspects are: Asset Planning,
Setting Service Levels, Managing Risk to drive asset related decisions, Minimizing Life Cycle
Costs, and Managing Asset Related Knowledge. It is also about balancing Service Levels with
Cost, and is extremely important to involve people throughout the organization in the AM
process instead of making it simply a staff function. It requires the right organizational arrangements to sustain gains achieved as the program evolves. This paper provides a case study
on the City of Columbus Department of Public Utilities’ asset management journey and provides
useful tips and guidance to other utilities that are considering asset management or have already
started their journey.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Effective Utility Management Practices, Improved Team Work, Improved Worker Morale, Organizational Sustainability, Plant Sustainability | No Comments »
New York City Department of Environmental Protection (DEP)
New York City, New York
Long term experience with the identification, evaluation, and implementation of innovative
technologies has shown that a structured framework in the decision-making process is crucial to
the success of the overall effort. A framework for identification, evaluation, and implementation
of innovative technologies that is applicable to a wide range of wastewater treatment
technologies was developed by the New York City Department of Environmental Protection
(DEP) Applied Research Program. By using the Innovative Technology Prioritization (ITEP)
framework for screening and prioritizing innovative technologies for further development and/or
large-scale testing, the City was able to focus Research and Development (R&D) efforts in
technologies that were viable within the current constraints faced by the City, saving in excess of
$1.5 million in R&D funding.
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Posted: May 20th, 2011 | Filed under: >1M, 100K-500K, 500K-1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Foam Control, Improve Plant Performance, Improved Plant Efficiency, Nocardia Control, Technology Management | No Comments »
Metro Wastewater Reclamation District (MWRD)
Denver, Colorado
In 2007, the Metro Wastewater Reclamation District teamed with Black and Veatch and Brown
and Caldwell to implement a Capital Project Management Program to manage expenditures
approaching $100M annually. As the Program began it was successful in managing many
elements across multiple areas, but over time delays began to occur in business process
improvement work and products. In order to address these problems, a best practices-based
strategic planning process was implemented to align the Program team around the Program
vision, reprioritize improvement efforts, and improve work process interaction among the team.
The ultimate goal was to establish a repeatable continuous improvement-based planning and
execution methodology to develop the annual Program Plan. Throughout 2009 the Program team
focused on implementing high priority initiatives and continuously measured performance on
objectives. The 2010 planning effort was much more efficient as the Program team embraced
this approach and adapted the lessons learned throughout 2009.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Improved Communication, Improved Plant Efficiency, Improved Plant Performance, Improved Strategic Planning, Improved Team Work, Plant Optimization | No Comments »
Sydney Water Corporation
Parramatta, Sydney (Australia)
Environmental constraints on urban growth led the Sydney Water Corporation (Sydney Water) to
implement an integrated water servicing strategy that included the piped supply of recycled water
to 36,000 new residential homes. Key lessons from introducing recycled water to residential
homes on such a scale are presented in the areas of managing public health risk, system design,
water conservation and community acceptance. The experience of developing Australia’s largest
residential recycling scheme informs consideration of dual reticulation as an option in integrated
water resource management.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Community Acceptance, Cost Savings, Environmental Impact, Improved Public Health, Optimized Water Resource Planning, Plant Sustainability, Reduced Carbon Footprint, Reduced Drinking Water Consumption, Water Conservation | No Comments »
Philadelphia Water Department (PWD)
Philadelphia, Pennsylvania
The Philadelphia Water Department (PWD) is currently evaluating the implementation of
various combined sewer overflow (CSO) control alternatives. This includes traditional
engineering approaches that rely on physical infrastructure (e.g., building large diameter
tunnels), as well as more “natural” approaches that rely on “green infrastructure” techniques
(e.g., vegetated bioswales, permeable pavement).This report provides a Triple Bottom Lineoriented
benefit-cost assessment of the CSO control alternatives under consideration by PWD.
The focus is on the benefits and external costs of the alternatives. The key finding of this report
is that the green infrastructure approaches generate a broader and more valuable array of
environmental, public health, and social benefits than do traditional CSO control strategies.
Benefits of green infrastructure evaluated and monetized include: Improved recreation
opportunities, increased property values, reduced heat-stress related fatalities, improved air and
water quality, green jobs, reduced energy use, and reduced disruption due to construction and
maintenance activities.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Combined Sewer Overflow (CSO) Control, Environmental Impact, Green Infrastructure, Improved Customer Relations, Improved Public Health, Improved Stormwater Management, Low Impact Development, Permeable Pavement, Plant Sustainability, Rain Gardens, Vegetated Bioswales | No Comments »
Upper Occoquan Service Authority
Centreville, Virginia
The cost of energy has become an increasing concern to water and wastewater utilities.
Economic drivers, combined with general industry concerns about energy supply reliability,
climate change, and sustainability have encouraged many utilities to consider alternative project
delivery methods to finance desired energy efficiency and renewable energy projects. One such
alternative delivery method is the Energy Performance Contract.
Energy performance contracting has been applied most actively by Energy Service Companies
(ESCOs) to implement building efficiency improvements at institutional facilities: universities,
schools, hospitals, and government buildings. It has been only within the past five years that
municipal water and wastewater utilities began using this alternative delivery method to
implement energy efficiency improvements at their treatment plants.
This paper provides an overview of energy performance contracting and the ESCO market. It
also presents a case study from a municipal wastewater utility in Virginia that is utilizing energy
performance contracting to implement energy efficiency projects: the Upper Occoquan Service
Authority in Centreville, VA.
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Posted: May 20th, 2011 | Filed under: >1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Efficiency, Energy Savings, Heat Drying, Plant Optimization, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Renewable Energy | No Comments »
City of Los Angeles
Los Angeles, California
This paper discusses the development of a unique sewer tunnel ventilation strategy for a future
City of Los Angeles wastewater project in the northern part of the City’s service area.
Air accumulation in sewer tunnels can be a major issue due to high air volumes generated both in
the sewer pipe and in drop structures feeding it. High air flows have many negative impacts
including limiting the liquid flow, accumulating odorous air that requires exhaust and treatment
using air treatment facilities (ATFs) at various locations, and in extreme cases causing high
pressure air pockets that can cause structural damage due to pressure alone.
The design team developed strategies to reduce those negative impacts by limiting the volume of
air entering and conveyed in the tunnel. This project is believed to be the first to use these
strategies for a sewer tunnel of this size. The paper also discusses alternative treatment
technologies for exhaust air.
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Posted: May 20th, 2011 | Filed under: >1M, Waste Water Treatment | Tags: Capital Cost Savings, Improved Air Treatment, Improved Tunnel Ventilation, Optimized Air Flow, Reduced Operating Costs | No Comments »