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 »
Ithaca Area Wastewater Treatment Facility
Ithaca, New York
The results of the Fenton reagent treatment of biosolids at a bench scale and at a full scale
operation, as well as the cost-benefit analysis, are presented here. We compare the results of one
year of full-scale operation of Fenton reagent treatment during 2008 against the normal operation
parameters for the period 2005 – 2007. The treatment of biosolids with Fenton reagent was tested
in a full-scale reactor at the Ithaca Area Wastewater Treatment Facility, IAWTF. The Fenton
reagent treated biosolids were returned back to an anaerobic digester for additional digestion.
The most relevant results were the reduction in the amount of final residual biosolids for disposal
(11.5% reduction), the increase in the percent solids content of the final residual biosolids (7.5%
higher), and a higher energy cogeneration output (13.0% higher specific biogas production, &
13.0% higher heat output). The net economic benefit was $78,000.00 per year.
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Posted: May 20th, 2011 | Filed under: 100K-500K, 500K-1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Improved Anaerobic Digestion, Improved Biogas Production, Improved Plant Efficiency, Reduced Biosolids Disposal | No Comments »
Manholes represent a rather complex structure for assessing its structural condition and
“leakiness” potential. Factors such as the assembly of components with multiple construction
materials and exposure mechanisms to rainfall and runoff make computational scoring and I/I
quantification logic complicated. Manholes have the potential to be significant sources of
extraneous infiltration/inflow (I/I) but it is difficult converting visual inspections into I/I
quantification. The American Society of Civil Engineers (ASCE) 2009 publication titled
Manhole Inspection and Rehabilitation and other publications were used to develop an analysis
tool for assigning infiltration/inflow (I/I) to standard manhole defects and projecting the I/I rates
to vary with specific storm event rainfall frequency, intensity, and duration. The tool also adjusts
the I/I rates depending the defect’s component location and on which one of four rainfall runoff
exposure mechanisms the manhole is exposed; sheet-flow, ponding/tributary limited,
ponding/tributary un-limited, and elevated. The tool’s I/I quantification process and development
basis improves the engineering integrity of rehabilitation cost effective analysis and prioritization
decisions.
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Posted: May 20th, 2011 | Filed under: Sanitary Sewer, Stormwater | Tags: Improved Manhole Rehabilitation, Improved Organization, Improved Plant Efficiency, Manhole Prioritization, Reduced Infiltration and Inflow | 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 »
Washington Suburban Sanitary Commission (WSSC)
Laurel, Maryland
The Washington Suburban Sanitary Commission (WSSC) serves 1.8 million residents with water
and wastewater service with 2 surface water treatment facilities and 5 wastewater treatment
plants. In an effort to reduce operating costs and encourage sustainable practices the
Commission entered into a series of agreements with an Energy Services Company (ESCO) to
perform Energy Performing Contracts (EPCs). These alternative delivery projects involved theCost
Commission conducting upgrades to water and wastewater treatment facilities based on
guarantees of reduced operating expenditures.
In this project delivery and financing method, the ESCO in conjunction with the Commission
and the owners engineer conducted preliminary evaluations of treatment processes in an effort to
identify opportunities for reduction in operating expenses (power consumption, demand
management, solids disposal and fuel usage, based on a 15 year payback period. Upon
agreement between the owner and the ESCO as to the process improvement, construction cost
and reduction in operating costs, the owner and ESCO entered in an agreement whereby the
ESCO designed and constructed the improvement (under a modified design-build process) and
the ESCO guaranteed the projected operations savings for a 15 year period.
The first series of project involved the expenditure of $10.2 M in construction and design cost
with a guaranteed annual savings of $700,000 per year. In the first two years of operation, these
projects have saved $1,500,000 per year. While these figures indicate that the Commission has
been able to have its cake and eat it too, “There ain’t no such thing as a free lunch”
(TANSTAFL)”. The process and implementation of these projects demonstrated a number of
lessons to the Commission in how to conduct the initial evaluation, design, construction and
verification of energy savings. This paper will detail the challenges and lessons learned from the
ESCO process and demonstrate the path to success for future ESCO projects.
The process demonstrated the importance of well defined and consistent design standard,
particularly for instrumentation and control, electrical and HVAC systems. The Commission
was challenged with developing and writing appropriate contractual terms at the preliminary
design stage, as that is stage at which the project cost is established and requirements for
equipment are developed. In addition, the Commission was challenged with balancing the
desires and requirements of multiple groups including operations, engineering, finance, and
power management. The paper will present examples of each of the challenges, along with solutions to the challenges that allow the Commission to continue with this project delivery
method with greater success.
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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Optimization, Energy Savings, Evironmental Impact, Improved Plant Efficiency, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions, Reduced Operating Costs | No Comments »
Odor control equipment is important to the wastewater industry throughout the world. It allows
wastewater plants and collection systems to operate with minimal impact on the surrounding
regions. One very prominent technology is engineered dry-scrubbing media. This media
consists of various base materials formed into spherical media through the processes of
agglomeration and impregnation. The base materials include adsorbents such as activated
alumina, activated carbon, and sodium bicarbonate. The liquid impregnants include potassium
permanganate, sodium permanganate, and potassium hydroxide. These materials combine to
form an engineered media having physical and chemical properties that allow contact with and
removal of odorous gases.
This paper focuses on reducing capital cost by increasing the velocity of air through an odor
control system. In the past, odor control systems performed well at face velocities of 60-100 feet
per minute (fpm) across a media bed. Experience and performance tests on installed systems
confirm this. In the examples sited here, systems have achieved acceptable life times as well as
efficiencies greater than 99.5%.
The efficacy of an air velocity increase depends on the following parameters: gas mass transfer
zone, media pressure drop, capital cost reduction, and energy consumption. These factors point
toward 125 fpm as the optimum velocity-increase point. The scrubber is also capable of
operating at 150 fpm with higher energy consumption. Wastewater plants can use these results
to evaluate scrubber options and meet budgetary constraints.
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Posted: May 3rd, 2011 | Filed under: Uncategorized | Tags: Decreased Energy Consumption, Engineered Odor Control Media, Improved Odor Control, Improved Plant Efficiency, Increased Cost Savings | No Comments »
Milton Regional Sewer Authority
Milton, Pennsylvania
Designed in the 1960’s and constructed in the mid-1970’s, the Milton Regional Sewer
Authority’s (MRSA’s) 3.420 MGD wastewater treatment plant (WWTP) is in need of a
complete facility upgrade. The upgrade will need to not only account for strict nitrogen
and phosphorus effluent requirements, but also seek out opportunities to minimize energy
dependence and operational costs through biogas production, electrical generation,
biosolids drying and sale of electricity to the Grid.
The end goal for this project is to create an energy independent, green wastewater
treatment facility. The objectives are to maximize energy recovery by exploiting all
reasonable sources; to minimize energy use throughout the facility; and to identify the
most feasible methods of energy recovery. Anaerobic treatment will be used were
applicable to meet these objectives through lower connected horsepower and biogas
production.
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Posted: May 3rd, 2011 | Filed under: <50K, Sanitary Sewer, Waste Water Treatment | Tags: Biosolids Management, Cost Savings, Energy Production, Energy Savings, Environmental Impact, Improved Plant Efficiency, Plant Optimization, Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Letchworth Avenue Wastewater Treatment Facility
Billerica, Massachusetts
When replacing equipment that has reached the end of its life cycle, breaking with tradition and
exploring the marketplace for industry trends and cutting edge technologies can often yield
substantial results. For example, when the Town of Billerica, Massachusetts, needed to replace
its aging belt filter press; rather than replacing the equipment in kind the Town installed a rotary
sludge press for dewatering of blended primary and thickened waste activated sludge, the first
installation in Massachusetts and one of only a few in New England, at its 5.4-MGD municipal
wastewater treatment facility.
Replacing a belt filter press with a rotary sludge press is a unit process replacement with a
smaller footprint, making design, construction, and installation a logical retrofit. Where the open
belt filter press presents greater exposure to odors, health hazards, and presents a challenging
work environment for operators, the rotary sludge press is fully enclosed, providing a more
operator friendly environment.
This paper presents a review of the piloting, design, construction, startup, and operation of
Billerica’s new rotary sludge press over the first year of operation.
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Posted: May 3rd, 2011 | Filed under: <50K, Waste Water Treatment | Tags: Cost Savings, Environmental Impact, Improved Plant Efficiency, Improved Working Conditions, Increased Cake Dewatering, Increased Process Reliability, Optimized Chemical Usage, Plant Optimization, Reduced Carbon Footprint | No Comments »
Post Point Wastewater Treatment Plant
Bellingham, Washington
The paper describes an approach to design and control of high purity oxygen (HPO) activated sludge treatment systems incorporating anaerobic zones for settleability control, efficient oxygen transfer, and control of dissolved oxygen concentration through variable speed drives. A case study from an upgrade project in Bellingham, Washington is used as an example of the approach. Results from upgrade of the Post Point WWTP provide proof that significant improvements can be made in the process control and energy efficiency of HPO plants. Improvements to sludge settleability can result from conversion from fully aerobic to anaerobic selector operation. Continuing improvements in oxygen transfer can make upgrade of impellers economical. Provision of variable speed drives reduces waste of DO, drive power, and HPO gas. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Energy Savings, Improved Oxygen Transfer, Improved Plant Efficiency, Improved Sludge Settleability, Reduced Loss of DO in the Effluent | No Comments »