Issue Focus: Industrial Energy Efficiency in the States
Energy Matters was a quarterly newsletter for DOE's Advanced Manufacturing Program (AMO). It provided in-depth technical articles to help industry professionals save energy, reduce costs, and increase productivity. These archived issues may contain broken links or information that is no longer accessible. Some of the following documents are available as Adobe Acrobat PDFs.
This issue highlights some programs, partnerships, and activities that focus on industrial energy efficiency in the states; many are either carried out with DOE's Industrial Technologies Program or modeled on ITP activities. Also included: how to reduce process heating energy consumption, make use of wireless sensors, and create a more energy-efficient wastewater treatment plant.
In This Issue
- DOE Works with the States on Energy-Efficient Industrial Products and Practices
- Purdue and Indiana WIRED Work With DOE to Train and Certify Industrial Energy Efficiency Practitioners
- Top 10 Ways to Reduce Steam and Process Heating Costs and Save Energy Now
- Featured Technology: DOE and Industry Create a New Generation of Wireless Sensors
- Spotlight: DOE Software Tools Essential to Energy-Saving Processes at Wastewater Treatment Plant
DOE Works with the States on Energy-Efficient Industrial Products and Practices
Because industry consumes more energy than any other sector in the country, discovering opportunities to improve industrial energy efficiency and use clean, renewable energy technologies can strengthen our economy, help protect our environment, and ensure greater energy independence. Through the Industrial Technologies Program (ITP), the U.S. Department of Energy (DOE) helps industries in every state of the nation use energy more efficiently.
After many years of successful collaborations, ITP is expanding its work with the states in some promising new areas. For example, a new financial agreement with the National Association of State Energy Officials (NASEO) is now in place to help ITP with outreach activities to the state energy offices (SEOs). The SEOs then provide information and assistance to organizations in their states that work on energy efficiency with industrial partners. Other new activities include partnership programs in Indiana (see the related article in this issue) and Wisconsin.
A New Web Site Focuses on the States
In addition to providing resources, energy assessment opportunities, and training to state organizations in these and other states, ITP has a new state-focused Web site designed to promote greater awareness and deployment of industrial energy efficiency practices and technologies in your state. By clicking on any state in the map on the site, readers can obtain the following:
- Statistics on industries in that state
- Economic indicators and a snapshot of industrial energy use in the state
- Links to training opportunities in the state that can help improve its industrial energy use
- Ways to contact experts who can provide services and resources to help increase the state's industrial energy efficiency.
The site lists ITP activities in these four categories:
Save Energy Now large-plant energy assessments, which are provided to qualifying facilities at no cost
Energy, waste, and productivity assessments provided by DOE's university-based IACs, which also can be obtained at no cost
Events and training to improve the efficiency of energy-intensive motor, pump, process heating, steam, and fan systems
R&D conducted at laboratories, universities, nonprofits, and private companies across the country to bring advanced energy and economic solutions to industry.
A Sampling of ITP's Work with States
Here is a snapshot of some of the information you will find on the new Web site. For example, in the State of New York, ITP has worked with more than 30 partners on R&D projects, such as one to develop intelligent extruder software for use in polymer compounding (PDF 940 KB), and on uncovering opportunities for savings through large-plant assessments conducted under DOE's Save Energy Now initiative. Download Adobe Reader. ITP also supports a university-based Industrial Assessment Center (IAC) at Syracuse University; IACs provide free energy assessments to eligible small and mid-sized industrial plants and make recommendations that can save the plants both energy and dollars.
Missouri is also home to an IAC based at the University of Missouri-Columbia. And ITP is working with at least 13 partners in the state on cost-shared R&D and on recommendations for obtaining near-term industrial savings through Save Energy Now. Successful R&D projects include one to develop new chromium tungsten alloys that can be used in designing hydrocracker and chemical reactors (PDF 1.3 MB). Download Adobe Reader.
ITP has been working with more than 45 partners in Texas on R&D projects and on identifying opportunities for industrial savings through Save Energy Now. In one project, ITP sponsored the development of an emissions control technology for the wood products industry that could provide significant energy and cost savings as well as environmental and health benefits (PDF 1.1 MB). Download Adobe Reader. The program currently supports an IAC at Texas A&M University that provides free industrial energy assessments to small and mid-sized plants while training the engineers of the future.
Farther west, in California, ITP is working with more than 30 partners on R&D projects and on assessments to uncover industrial savings opportunities through Save Energy Now. One R&D project of note was carried out to develop a high-efficiency, ultra-low-emission, integrated process heater system for the petroleum and chemicals industries (PDF 292 KB). Download Adobe Reader. ITP also supports IACs at San Diego State and San Francisco State universities and at Loyola Marymount University in Los Angeles.
Be sure to visit the new ITP State Activities site to learn more about industrial energy efficiency and savings opportunities in your state.
Purdue and Indiana WIRED Work With DOE to Train and Certify Industrial Energy Efficiency Practitioners
A good example of effective federal and state collaborations can be found in a new program in which U.S. Department of Energy (DOE) Qualified Specialists work with Purdue University's Technical Assistance Program (TAP) Energy Efficiency Services and Indiana's Workforce Innovation in Regional Economic Development (WIRED) initiative to increase industrial energy efficiency. The new worker training and certification program will benefit up to 28 manufacturers in North-Central Indiana in the very first round of activities.
TAP Energy Efficiency Services is introducing the Energy Efficiency Practitioner Certification Program in the 14-county WIRED region through a competitive solicitation for applications from regional manufacturers. Each manufacturer selected can send up to five employees through the program free of charge, thanks to funding from WIRED.
The new training and certification program should be especially useful to facility engineers, plant managers, end users, purchasing agents, decision makers, and other professionals who use or purchase energy in their respective plants. Purdue TAP also hopes to make the program available statewide later in the year on a fee-for-service basis.
Certifying In-Plant Practitioners of Energy Efficiency
The program is designed to make manufacturers more knowledgeable about energy-efficient industrial processes, provide technical assistance, and build skills among manufacturing employees. It should also help to create a new network of energy-conscious firms in the region that are increasing their productivity and profits through more efficient use of energy.
On-site training will be provided by instructors from TAP Energy Efficiency Services and TAP's Manufacturing Extension Program (MEP) Center, which is an affiliate of the U.S. Department of Commerce's National Institute for Standards and Technology (NIST) MEP. Off-site workshops on evaluating industrial process systems for improvement opportunities will be conducted by numerous Qualified Specialists in the DOE Industrial Technologies Program (ITP).
All the training modules have been developed by DOE, industry trade groups, manufacturers, engineering firms, or Purdue faculty and staff. Many of these modules will provide trainees with continuing education units they can use in obtaining or maintaining their professional accreditation.
As part of a seven-and-one-half-day certification course that takes a system-wide approach to energy efficiency, trainees will select three or more off-site, one-day BestPractices workshops on optimizing various industrial systems. These include fans, compressed air systems, motors, pumps, process heating systems, steam systems, and more. During the first day of their on-site training, participants will also make use of DOE's Quick Plant Energy Profiler (Quick PEP) software to get a feel for the best opportunities for savings in their plants.
The 28 companies will be selected from among all applicants by TAP and WIRED reviewers. Three energy-intensive industry groups in the north-central WIRED region are the focus of the first solicitation: transportation-related manufacturers, including automakers and related suppliers; primary metal manufacturers; and fabricated metal products manufacturers. Firms in other industries could also apply.
Required for Certification: An Energy-Saving Project
To be certified, trainees must identify and implement an on-site energy efficiency project. A Qualified Specialist will spend about half a day at each plant that sent a team of trainees through the course. The Qualified Specialist will help trainees identify potential projects, rank them in terms of priorities, and develop an implementation strategy for at least one project.
At the end of the training period, each company represented in the program will have 12 months to implement an actual energy efficiency project. It will also have a specified amount of time to monitor, measure, and verify the energy savings resulting from the project and convey the results to TAP and WIRED.
This requirement virtually guarantees both reductions in energy use and increases in profitability in the region. Estimates indicate that this manufacturing-intensive part of the state could be spending more than $100 million on natural gas and $150 million on electricity each year. The first 140 employees or so who take the course are likely to not only save energy and dollars in their own plants but also help spread the word to other firms they deal with in the course of their business operations, thus propagating the benefits of the program.
For more information, contact Ethan Rogers, Manager of Energy Efficiency Services, Purdue Technical Assistance Program, email@example.com. And for more information about a joint project between DOE Industrial Assessment Centers and the MEP, see a related story in the Spring 2007 issue of Energy Matters.
About the Program's Key Providers
Purdue University's TAP Energy Efficiency Services is supported and funded by the Indiana Office of Energy & Defense Development (OED). As part of the Office of the Lieutenant Governor, the OED manages renewable energy and energy efficiency programs and engages in policy development and advocacy of the Hoosier Homegrown Energy Plan, which promotes energy resource development in Indiana. As the state's energy office, the OED receives funding from the ITP State Energy Program and uses some of those funds to support TAP Energy Efficiency Services. The TAP MEP Center is supported by NIST.
WIRED is a federal initiative designed to energize the nation's economy through regional economic development partnerships and workforce education and training. In 2006, the U.S. Department of Labor awarded $15 million each to 13 U.S. regions, including a grant to the Indiana Department of Workforce Development (IDWD), which covers the 14-county Indiana WIRED region. The IDWD selected Purdue to oversee the Indiana WIRED project.
Top 10 Ways to Reduce Steam and Process Heating Costs and Save Energy Now
Large U.S. plants can save millions of dollars in energy and maintenance costs each year by improving the energy efficiency of their steam or process heating systems. This was one of the major findings of U.S. Department of Energy (DOE) Energy Experts and plant assessment teams when they evaluated the energy efficiency of industrial steam or process heating systems in 200 large, energy-intensive U.S. plants in 2006.
In the Winter 2007 issue of Energy Matters, we described the top 10 energy-saving recommendations in terms of how frequently they were made in all the plant energy assessments conducted in 2006. Since then, energy efficiency specialists in the DOE Industrial Technologies Program (ITP) and at Oak Ridge National Laboratory have analyzed how much energy and money those plants could save by following the recommendations in their Save Energy Now energy assessments. They also looked at potential emission reductions and other benefits. The full report on the 2006 assessments is available on the Results page of the Save Energy Now Web site.
Tables 1 and 2, which are based on the report's findings, list the top five money-saving recommendations among all those made for industrial process heating systems and the top five for steam systems, out of about 30 recommendations made for each type of system. The tables also include the potential natural gas savings and estimated environmental emissions reductions associated with each recommendation.
Following each table are links to ITP resources, such as tip sheets, produced by technical experts in energy-efficient industrial systems. These resources, and those listed at the end of the article, can help you start to Save Energy Now in your own plant.
Five Ways to Reduce Process Heating Energy and Maintenance Costs
Table 1 shows the top five potential money-saving recommendations made in the 2006 Save Energy Now energy assessments that focused on improving process heating systems.
|Recommendation from 2006 Save Energy Now Process Heating Assessments||Total Potential Cost Savings
|Total Potential Natural Gas Savings
|Total Potential Reductions in Carbon Dioxide
|Recover and use heat from industrial furnaces||$20 million||1 million||182,000|
|Use heat cascading||$16 million||2 million||142,000|
|Use proper heating methods||$13 million||1 million||74,000|
|Use proper furnace insulation and maintenance techniques||$12 million||1 million||124,000|
|Reduce flue gas oxygen content||$9 million||878,000||111,000|
|*Rounded to the nearest thousand or million.|
Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.
1. Recover and use heat from industrial furnaces:
To make use of the considerable heat from industrial furnaces, see these tips:
2. Use heat cascading:
The heat from flue or exhaust gases in higher temperature processes can be used to supply heat to lower temperature processes, as described in this tip:
3. Use proper heating methods:
To increase your process heating savings by replacing inefficient, uneconomical methods with efficient, economical systems, see these tips:
4. Use proper furnace insulation and maintenance techniques:
To avoid localized losses in furnaces, consider these tips:
5. Reduce flue gas oxygen content:
To lower the oxygen levels in exhaust gases in order to raise available heat levels and improve energy efficiency, see this tip:
Five Ways to Reduce Steam System Energy and Maintenance Costs
Table 2 shows the top five potential money-saving recommendations made in 2006 during Save Energy Now energy assessments that evaluated industrial steam systems.
|Recommendation from 2006 Save Energy Now Steam System Assessments||Total Potential Cost Savings
|Total Potential Natural Gas Savings
|Total Potential Reductions in Carbon Dioxide
|Reduce steam demand||$89 million||8 million||1 million|
|Use alternate fuel||$78 million||14 million||376,000|
|Improve boiler efficiency||$43 million||4 million||284,000|
|Add or modify backpressure steam turbine||$34 million||130,000||166,000|
|Improve condensate recovery||$24 million||2 million||151,000|
|*Rounded to the nearest thousand or million.|
Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.
1. Reduce steam demand:
For information about opportunities for improving the energy use and performance of steam systems as well as the benefits of a systems approach, see this resource from ITP:
2. Use alternate fuel:
To switch to a fuel with a higher theoretical combustion efficiency and save money on fuel, see these tips:
3. Improve boiler efficiency:
To reduce boiler losses and use less fuel to achieve the production rate you need, review these tips:
4. Add or modify a backpressure steam turbine:
To increase your total steam usage and potentially reduce your overall energy costs, see these tips:
5. Improve condensate recovery:
To increase the condensate returned to the boiler and supply hotter water to the boiler feedwater system, try this tip:
To review the entire report on the 2006 plant assessments, Results from the U.S. DOE 2006 Save Energy Now Assessment Initiative, you can visit the ITP Save Energy Now Web site or order the CD. And for more information about how to improve your plant's process heating or steam system efficiency, see the following ITP resources.
To improve process heating system efficiency:
- More process heating tip sheets
- Improving Process Heating System Performance: A Sourcebook for Industry (PDF 1.2 MB)
- More technical handbooks, guides, and technical briefs on process heating
- Process Heating Assessment and Survey Tool (software)
- Process heating assessment training
To improve steam system efficiency:
- More steam system tip sheets
- Improving Steam System Performance: A Sourcebook for Industry (PDF 1.3 MB)
- More technical handbooks, guides, and technical briefs on steam systems
- Suite of Steam System Assessment Tools (software)
- Steam system assessment training
And for more information about Save Energy Now energy assessments, including activities planned in 2007, please visit the Save Energy Now Web site.
Featured Technology: DOE and Industry Create a New Generation of Wireless Sensors
Some exciting new wireless sensors are proving to be highly effective in monitoring and controlling industrial equipment and processes. These sensors, which were developed with support from the U.S. Department of Energy (DOE) Industrial Technologies Program (ITP), can also help improve process reliability, reduce waste and downtime, and enhance the safety of employees, all of which ultimately boost a plant's productivity and profitability.
ITP has been involved with wireless sensor work since 1999. Sponsored activities are designed to identify, develop, and deploy integrated measurement systems for operator-independent control of manufacturing processes. Technologies are developed for application in more than one industry, and systems are designed to work in harsh industrial environments. Ultimately, these systems should enable a plant to achieve a high level of productivity and quality as well as increase the plant's energy efficiency by as much as 10% (for more information, see Industrial Wireless Technology for the 21st Century (PDF 1.3 MB) on the ITP Web site). Download Adobe Reader.
New wireless sensors not only eliminate the cost of the wiring and cabling needed for conventional sensor technologies, they also save money by contributing to a plant's overall energy efficiency. They can quickly identify inefficiencies so plant managers can correct them before they become serious problems. They can also be cost-effective in applications not directly related to energy efficiency.
Several new products are based on technologies developed with the technical assistance and funding provided through the ITP Sensors and Automation program area. Selected through a competitive bidding process, industrial partners in this work include, among others, General Electric Company (GE); Sensicast Systems, Inc.; Honeywell International; and Eaton Corporation. GE, Sensicast, and Honeywell have already introduced new sensors into the marketplace based on wireless technologies developed under ITP sponsorship, and Eaton should not be far behind.
One project partner has estimated that ITP-sponsored research and development projects with industry have made wireless sensors a reality five years sooner than they would have been without ITP as a catalyst. This work has also alerted the company's business units to the prospects for wireless measurement systems.
Working with ITP, GE Develops Important New Products
GE has introduced several products based on the robust radio technology developed in ITP-sponsored work. One product developed by GE, LabWatch™, is used in stability, environmental, and facility monitoring applications and is especially suitable for the pharmaceutical and biotechnology industries. GE reports that LabWatch is capable of precise monitoring combined with alarming, reporting, and data collection features.
Another GE product, the Kaye RF ValProbe®, integrates radio frequency mesh technology with established thermal validation loggers produced by GE Sensing. The RF ValProbe system includes RF wireless loggers, a base station, and software. The loggers provide accurate measurements of temperature, humidity, and any 4-20 or 0-10 V output. GE notes that the software is easy to use and incorporates such features as a self-configuring mesh network and automatic data collection.
GE is also developing a wireless sensor that can be used to monitor industrial motors as well as environmental conditions in industrial settings. Electric motors use 60% of the electricity consumed in industry, and motor failures can cause costly losses in production time. Purchasing wireless sensors for motors and other important equipment can be a far better solution than spending from $40 to as much as $2,000 per foot on wiring for conventional sensors.
The GE system is both diagnostic and prognostic. It monitors the motor's condition, performance, and efficiency. The central station analyzes data obtained from the wireless sensors and can identify which motor components need maintenance. The system also projects which motors will fail next, and when, so that repairs and replacements can be done without sacrificing productivity.
For more information, visit the GE Sensing division's Web site.
Sensicast Introduces a Robust Wireless Sensor Network
Sensicast Systems, a GE subcontractor, has used the robust radio developed in an ITP-funded project to link with standard-interface sensors and wirelessly provide measurements of temperature, humidity, pressure, flow, vibration, voltage, current, and motion, among other variables. With an earlier Sensicast sensor technology, up to 30% of the data monitored by each sensor was not received at the designated monitoring station. Today, because of technical advances achieved under the ITP program, nearly 100% of the data from each sensor is received.
Using sensors to monitor and optimize the performance of compressed air systems can help industrial facilities operate at peak efficiency. In the past, however, it was not practical because of the high cost of wiring the sensors to a monitoring station. Today, a new low-cost wireless sensor technology, funded by DOE and developed by GE and Sensicast, could revolutionize the operation and optimization of compressed air and other systems.
The wireless technology was field-tested in an actual paper mill's compressed air system to capture performance data from three compressors. Employees of the paper mill were so pleased with the technology's performance that they decided to use it to monitor the demand side of the compressed air network. In less than 24 hours, seven wireless flow meters were inexpensively deployed throughout the facility to identify inefficiencies in compressed air use. Because of the resulting energy savings and the ease of implementing the technology, the paper mill decided to add five more wireless demand-point measurements.
Wireless radio technology initially created by Sensicast under ITP's sponsorship has also been incorporated in systems used to perform two key roles in the Ferreira Group headquarters building in Branchburg, New Jersey, which is the nation's first net-zero-electric commercial building. As such, the building's photovoltaic (solar electric) system produces more electricity on an annual basis than the building takes from the utility power grid.
First, wireless sensors enable the building's photovoltaic array to be tuned for maximum efficiency while simultaneously identifying any array malfunctions. The SensiNet wireless sensor network generates a maintenance request automatically if problems are found, providing maintenance personnel with the exact location of the problem.
Second, sensors monitor the building's energy-consuming systems and wirelessly link this information to a display that provides a comprehensive picture of the status of the building's systems. A control system uses this information to minimize the building's energy consumption. Over a year's time, the building will produce an extra month's worth of electricity, which is then sold back to the grid.
For more information, see Sensicast's Web site.
Why Go Wireless?
- Lower installation and maintenance costs
- Ease of replacement and upgrading
- Reduced connector failure
- Greater physical mobility and freedom
- Practical deployment of micro-electromechanical systems (MEMS) technology
- Faster commissioning
Honeywell's OneWireless Solution Supports Multiple Applications
ITP also supported work that has resulted in Honeywell's OneWireless universal mesh network. The wireless technology developed as part of a cost-shared contract with DOE has been incorporated into this second-generation network.
Honeywell reports that the new network was developed to support a number of wireless-enabled applications and devices within a single environment. The network is simple to manage, easy to upgrade, and efficient to operate, and it supports multiple industrial protocols and applications simultaneously. Its key attributes include a single, plant-wide infrastructure that is relatively low in cost; an ability to connect sensors simultaneously to a variety of protocols, such as HART, OPC, and Modbus; and high reliability and flexibility.
The OneWireless network was developed to optimize industrial operations, provide reliability, assure compatibility, help provide easy access to data, and increase security, asset life, and worker safety. The network is particularly useful for process monitoring, inventory management, health and safety assurance, and environmental compliance. Like other systems funded through ITP, the Honeywell system uses a mesh network to ensure automatic rerouting should any element fail.
Honeywell is quite aware of the value of standards that will make wireless sensor systems compatible with each other and able to function in the presence of other kinds of wireless systems, such as cellular phones. Among the standards-setting groups that Honeywell supports is the ISA SP100 committee on wireless systems for automation.
ITP encourages all its contractors to participate in current standards-setting activities. And all have agreed to make any technological or other changes needed to ensure that their systems conform to new standards.
For more information, see the Honeywell Process Solutions Web site.
Eaton Works to Cut Motor Maintenance Costs, Improve Reliability
With support from ITP, Eaton has been developing a low-cost wireless motor monitoring system that continuously measures line voltage and current to evaluate motor energy use. This system will gather energy data based on Eaton's novel online inferential algorithms for energy estimation and condition-based monitoring of electric motors and connected loads.
Advanced energy management monitoring and diagnostic systems in medium and large electric motor applications (above 200 hp) are providing energy savings and economic benefits as well as reduced environmental impacts. However, 98% of all electric motors in industry are less than 200 hp. If monitoring, protection, and prognostic systems similar to those for large electric motors were implemented for smaller motors, industry could reduce the energy used in process areas by an estimated 5% to 18%.
Eaton is working to achieve this level of energy savings through novel, nonintrusive energy, efficiency, and wellness monitoring. One focus of the work is to research, test, develop, and deploy a wireless sensor network for advanced energy management solutions.
The technology will support open wireless protocols and be self-configuring, robust, and secure in industrial environments, and it will enable Eaton's novel online electric motor energy and condition monitoring. This could dramatically improve performance to minimize the adverse effects of coexistence, electromagnetic interference, and electromagnetic compatibility.
For more information about Eaton Corporation, see the company's Web site.
Much more has come from, and continues to come from, ITP's wireless projects. The work ranges from hardware to software to the creation of industry standards. These standards are likely to be based on one or more of the technologies created by ITP's industrial partners and contractors. Once the standards are adopted, all participants in the standard-setting activity have agreed to make their systems conform to them.
Permeating this work is the excitement of knowing that DOE funding is helping to create a whole new generation of industrial sensors. For more information and updates, be sure to visit the ITP Sensors and Automation Web site regularly.
DOE Software Tools Essential to Energy-Saving Processes at Wastewater Treatment Plant
For the Metropolitan Syracuse Wastewater Treatment Plant (Metro WWTP) in Onondaga County, New York, keeping up with the latest technologies in their wastewater treatment process is key to saving energy and money.
Metro WWTP provides wastewater treatment for 270,000 people and many industrial and commercial customers. A significant amount of energy is consumed while treating an average of 80 million gallons of wastewater daily. In order to improve efficiency at the plant, engineers began upgrading several wastewater treatment processes in 2004.
Utilizing two U.S. Department of Energy (DOE) Industrial Technologies Program (ITP) BestPractices tools, MotorMaster+ and the Pumping System Assessment Tool (PSAT), Metro WWTP implemented a system-level project to improve energy efficiency and validate the pump maintenance program.
By retrofitting the motors on waste-activated sludge pumps with variable-frequency drives, installing a biological aeration filtration system instead of aeration blowers, and replacing 25-year-old low-lift impellers, Metro WWTP achieved the following:
- A reduction in the number of 100-horsepower blowers from 21 to 13
- A lower annual energy consumption of 2.81 million kilowatt-hours, resulting in a cost savings of $207,500
- Better control of waste gas, reducing natural gas purchases by 270 MMBtu per year, for a cost savings of $1,500
- Total implementation costs of $233,000 for a simple payback of 13 months
The analysis provided by the MotorMaster+ and PSAT tools helped Metro WWTP engineers decide how to optimize the wastewater treatment process—projects and methodologies that can be applied to virtually all wastewater treatment and industrial facilities that require water in their processes.
Thomas W. Devine is a Qualified Pump System Specialist with more than 12 years of experience in the planning, design, construction, and start-up of the power distribution, control, and instrumentation systems that can be found in municipal, industrial, and commercial facilities. In his current role at Stearns & Wheler LLC, he specializes in process and energy audits and evaluations for municipalities and industrial plants.
NOTICE: This online publication was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.