Bryan Wastewater Treatment Plant
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.
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 »
Humber Treatment Plant (HTP)
Toronto, Ontario (Canada)
The Humber Treatment Plant (HTP) was experiencing severe settling problems. An opportunity
to improve the performance of the HTP was seized by the plant’s Senior Engineer by developing
and implementing a program of repair, continuous assessment, analysis, and tuning to ensure
optimal operation of the aging infrastructure. Through the strategic utilization of existing inhouse
expertise and resources, a new benchmark of excellence, serving the community through
improved and consistent effluent quality with accompanying odour reductions, was established.
This achievement was accomplished paradoxically using less energy and chemicals, thus,
significantly reducing the Humber’s environmental footprint. The direct delivery of these
services by City staff, while further enhancing in-house knowledge, skill, and stewardship,
eliminated the delays associated with project delivery using external contractors and made it
possible to reap the immediate rewards. The monetary benefits to the City are savings in
operating costs of $550,000 per year and capital savings of $6,000,000.
Posted: May 20th, 2011 | Filed under: 500K-1M, Waste Water Treatment | Tags: Capital Savings, Decreased Energy Consumption, Improved Plant Sustainability, Operating Cost Savings, Reduced Carbon Footprint, Reduced Odor Problems | No Comments »
Dallas Water Utilities (DWU)
Dallas Water Utilities (DWU) has identified multiple projects within their wastewater treatment
plants (WWTPs) to support the Green Dallas Initiative for energy conservation and
sustainability. In 2010, a new co-generation facility at the Southside Wastewater Treatment Plant
(SWWTP) will be brought on-line. This facility will utilize digester gas for electricity
production. As part of the Green Dallas Initiative, and to optimize the co-generation facility, the
feasibility of adding high strength wastes to the anaerobic digesters at SWWTP to increase the
digester gas production was evaluated.
Posted: May 20th, 2011 | Filed under: 100K-500K, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Electricity Production, Environmental Impact, Improved Plant Sustainability, Increased Digester Gas, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Annacis Island Wastewater Treatment Plant
Vancouver, British Columbia (Canada)
Annacis Island Wastewater Treatment Plant which is operated by Metro Vancouver, is leading
the way in working within a carbon based regulatory environment. British Columbia has
instituted carbon reduction legislation province wide, a leader in North America. As a result
public entities, such as Metro Vancouver, must be carbon neutral by 2012. In response the utility
is holistically investigating different approaches to achieve the required GHG reductions. One
approach now being actively pursued is the implementation of co-digestion at Annacis Island.
Having developed a the scope for a full co-digestion program at the plant, a pilot facility was
constructed to provide further process controls as well as a start at reducing emissions by codigesting
material at the plant. This project also provided Metro Vancouver a basis of handling
its own sludges from other wastewater treatment plants on an emergency or planned basis by
dual tasking the receiving facility to receive both sludges and co-digestion substrates.
Posted: May 20th, 2011 | Filed under: 500K-1M, Waste Water Treatment | Tags: Cost Savings, Energy Production, Environmental Impact, Improved Plant Performance, Improved Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Milwaukee Metropolitan Sewerage District (MMSD)
Significant opportunities exist to increase renewable energy production using existing municipal
anaerobic digesters. Many wastes can be added to co-digest more carbon and produce more
methane. The objectives of this study were to identify and compare potential co-digestates,
determine synergistic, antagonistic and neutral co-digestion outcomes, quantify performance of
co-digestion for selected wastes and estimate economic benefits. Over 80 wastes were identified
from 54 facilities within 160 km of an existing municipal digester. The most promising wastes
(26 wastes) were characterized by biochemical methane potential (BMP) and other testing. A
simple economic comparison identified the greatest benefits for seven co-digestates.
Performance was investigated using bench-scale digesters receiving synthetic primary sludge
with and without co-digestates. Methane production rates in co-digesters were as much as 180%
greater than anticipated from the additional chemical oxygen demand (COD). Therefore,
significant synergism was observed. The VS destruction efficiencies were 49 and 33% higher
when co-digestates were present. Co-digestion is one method to increase renewable energy
production via anaerobic digestion.
Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment | Tags: Cost Savings, Environmental Impact, Improved Plant Performance, Improved Plant Sustainability, Increased Biogas Production, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
Gwinnett County Department of Water Resources
The F. Wayne Hill Water Resources Center (FWHWRC), owned and operated by the Gwinnett
County, GA, Department of Water Resources (DWR), is an advanced wastewater treatment plant
which currently discharges into the Chattahoochee River and Lake Lanier. The FWHWRC
maximum month design flow is 60 million gallons per day (mgd) and currently about 30 mgd of
wastewater is received.
In light of rising energy costs and declining revenues reflective of the continuing, severe
economic downturn that began in 2007, the Gwinnett County DWR began an initiative to make
the best possible use of resources under DWR control, including renewable energy resources.
DWR retained CH2M HILL to identify and evaluate opportunities to improve resource
utilization and reduce energy costs at the FWHWRC. The results of the evaluations, procedures
for capturing stimulus funding, and technologies employed are discussed in this paper.
The energy types considered for the FWHWRC were biogas derived from anaerobic digestion,
solar, wind, and low-head hydropower. A screening analysis concluded that biogas combustion
to produce power and heat was the optimum alternative.
Next, a Business Case Evaluation (BCE) was conducted to determine if the construction and
operation of a gas-to-energy facility would be economically feasible. The BCE considered
several different scenarios for generating power from biogas, including biogas production with
and without addition of fats, oil & grease (FOG) and high strength waste (HSW) to the existing,
anaerobic sludge digesters.
The BCE concluded that a gas to energy facility based on an internal combustion engine (ICE)
was feasible. The proposed system, in addition to continuously generating electrical energy for
use at the FWHWRC, would be capable of producing sufficient heat to keep the anaerobic
digesters operating in the mesophilic temperature range of 95-100 degrees Fahrenheit (F). By
capturing the heat produced by the ICE, in addition to generating power, the system would have
a total energy-recovery efficiency approaching 80%.
The BCE recommended a gas to energy facility of approximately 2 megawatts (MW) in capacity
at the FWHWRC. The biogas requirement at a nominal 600 British Thermal Units (BTU) per
cubic foot (ft3) for an ICE of this capacity is approximately 520 standard cubic feet per minute
(scfm). However, as the FWHWRC is at only about 50% of its total design capacity, the
currently available biogas is considerably less than 520 scfm, and a purchased natural gas fuel
blend would be required to obtain full power generation and heat recovery benefits. To minimize purchase of natural gas, maximize biogas, and as a result improve the return on
investment in the cogeneration system, DWR next investigated addition of FOG and high
strength waste (HSW) to the anaerobic digesters to supplement the solids feed. The project was
made even more attractive by DWR’s successful pursuit of funding under the American
Recovery and Reinvestment Act (ARRA), as administered by the Georgia Environmental
Facility Administration (GEFA), and from the U.S. Department of Energy (DOE).
A schematic design of the system with specifications was prepared for competitive selection of a
design-build contractor. The design-build contract was awarded in October 2009. The contract
value is $5.19 million and includes the installation of a 2.1 MW engine generator along with
digester gas cleaning and drying equipment. The gas-to-energy facility is expected to reach
substantial completion by the end of 2010 with contractual completion in May 2011.
A second RFP for the design and construction of a FOG and HSW receiving facility was
advertised in February 2010. The design-build contract was awarded in June 2010 at a contract
value of $3.16 million. Its completion and startup will closely follow the completion and startup
of gas cogeneration facilities.
Once operational, the FOG/HSW handling and cogeneration facilities will have the potential to
save over one million dollars annually in power costs and generate more revenue in FOG and
HSW disposal fees. When operating at its rated capacity, the resulting power production will
offset the amount of fossil fuel used to generate over 17,000 MW-hours of electrical power
Posted: May 20th, 2011 | Filed under: 500K-1M, Stormwater, Waste Water Treatment, Water Treatment | Tags: Cost Savings, Energy Savings, Environmental Impact, Heat Production, Improved Energy Production, Improved Plant Sustainability, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »
San Francisco Public Utilities Commission
San Francisco, California
When the City and County of San Francisco (City) first began its land application program in
Solano County in 2000, it was with an eye toward a sustainable future. Significant odors and
truck traffic were generated near a newly developed retirement community, and outraged citizens
were quick to complain about the land application practices to Solano County staff. By winter of
2002, it appeared that the practice of land application in Solano County was over. The San
Francisco Public Utilities Commission (SFPUC), along with its sister agency, the East Bay
Municipal Utilities District (EBMUD), moved swiftly to begin engaging with stakeholders. The
end result was a revised local ordinance that addressed public concerns associated with noise,
traffic, and odors, but allowed continued Class B land application. Since that time, the two
agencies have continued to engage with the community by participating in routine biosolids
stakeholders meetings and meeting annually with the Solano County Board of Supervisors. In
addition, San Francisco has taken a more proactive role in managing its biosolids. Initiatives
include enrollment in the National Biosolids Partnership’s Environmental Management System
program, inspections of land application sites, increased biosolids monitoring, and participation
in biosolids stakeholder group meetings. The Solano County ordinance that allows Class B land
application was recently extended for another five years, an achievement that would likely not
have been possible without the extensive outreach efforts of San Francisco and other Bay Area
Posted: May 3rd, 2011 | Filed under: >1M, Waste Water Treatment | Tags: Enhanced Interaction with Stakeholders, Improved Customer Relations, Improved Plant Sustainability, Plant Optimization | No Comments »
Metropolitan Water Reclamation District of Greater Chicago
The District’s mission includes the protection of our water environment, specifically the water
quality of Lake Michigan, the region’s drinking water source, at all times in compliance with our
NPDES permits. All of the energy management measures listed above were implemented
without compromising or diminishing our ability to meet our primary goal. As an environmental
organization, the District has a responsibility to not only to achieve its primary function of
treating wastewater, but also to do so in an environmentally responsible manner.
The measures discussed above ultimately result not only in O&M cost savings but energy use
reduction. The decrease in energy use reduces the emissions of greenhouse gases, which has
taken on a new significance with the current concern regarding global warming and its predicted
dire effects on the planet and its ecosystems. They also demonstrate how vigilant maintenance of
public systems can have benefits above and beyond the immediate results.
The success of any initiative is directly dependent on the knowledge, dedication and efforts of
personnel involved not only in establishing protocol, but also in implementing and performing
the associated tasks on the daily basis. The District’s success, as measured by the cost savings
and energy reduction shown in the tables above, demonstrates the ability of District personnel to
work collaboratively as a team. The District will continue to seek additional measures to be
implemented at all facilities to not only save taxpayer money but also to operate more efficiently
to better improve the overall environment.
Posted: August 24th, 2010 | Filed under: >1M, Sanitary Sewer, Waste Water Treatment, Water Treatment | Tags: Energy Savings, Environmental Impact, Improved Plant Sustainability, O&M Cost Savings, Reduced Carbon Footprint, Reduced Greenhouse Gas Emissions | No Comments »