Dr. Teresa Valentine PhD, PE, BCEE receives Environmental Stewardship Award.

Dr. Teresa Valentine PhD, PE, BCEE receives Environmental Stewardship Award.

Dr. Teresa Valentine, Phd, PE, BCEE, managing principal of Valentine Environmental Engineers, is the recipient of the 2015 Environmental Stewardship Award from the AZ Water Association. The award recognizes members for their dedication to exceptional water management practices which serve to protect the environment and enhance the water and wastewater industry in Arizona

Valentine’s work as a professional engineer, a woman business owner, and environmental steward of local, regional and global water initiatives were cited in giving her this honor.

“Teresa also has provided us with excellent services on near and long term planning for needed improvements to our water and wastewater systems with an eye towards sustainability, energy efficiency, and reduced operations and maintenance, “ said Wendy S.W. Barnett, president, Utilities, Inc. Arizona / Nevada. “Teresa’s interest in our environment is apparent.”

To accomplish Valentine’ vision to deliver innovative solutions that build for a future of clean water and help improve the quality of life for people worldwide, Valentine has built a process that champions system innovation and efficiency focused strategies in in all stages of planning, design, construction, and maintenance solutions.

“Receiving an award like this shows our dedication to providing the best service to our clients and the environment. We are grateful for the opportunity in our profession to work on behalf of the environment, and provide water engineering solutions that help municipalities, private companies, and our overall water industry save energy, increase efficiencies, and improve operations,” said Valentine, who will receive the award today at the 88th annual conference and exhibition in Glendale, AZ. “Preserving water for generations to come and ensuring everyone has access to drinking water is our passion.”

Valentine also enjoys her time as a Girl Scout leader and president of the her children’s PTO, and supporting local and national organizations, such as Water for People, AZ Water Association, Compassion, Feed my Starving Children, YMCA, and St. Mary’s Food Bank.


Valentine Environmental Engineers has been an advocate for water recycling technology for years and is at the forefront of grey water reuse and water reuse.  They have designed and managed multiple projects over the past decade blazing a trail for others to join this ideal.  “Preserving our fresh water supplies is important but eventually we will have to adjust our technology and how we view our water.  Water engineers and water companies need to collaborate and understand the need to recycle water from tap to toilet back to tap again,” says Dr. Teresa Valentine, managing principal.

Many countries are already doing this in large quantities because of the short water supplies in their region such as: Australia, Singapore, and Israel.

Whether water recycling is something you are doing today or plan to do in the future, the critical element for success is communication and education.  The tools NDEEP developed are based on research findings around perceptions and beliefs of stakeholders regarding recycled water.

There are three key questions we need to ask ourselves and we need to consider for the future of water in our communities especially here in our own backyards in the Southwest.

  1. What is the big picture? Being transparent and thinking about the complete water scenario is critical to give our communities and our citizens the facts they need to determine what is best for them.  NDEEP research shows that we cannot just communicate about water recycling, we need to help the public understand the entire urban water cycle, and how drinking water is produced, and primarily the risk in drought-stricken areas and the risk we face.
  2. What are others doing – what’s working, what’s not? It is our responsibility to learn from other best practices in our field and use those to improve our master plans and design philosophies.
    Another tool NDEEP created was a Global Connections Map showing information featuring expert and citizen commentary about potable water recycling schemes all over the world – including more than 50 videos featuring interviews with key personnel from the plant engineer and regulators of a particular scheme, to local politicians and citizens.
  3. How can we work together? We understand the importance of collaborating with municipalities, private companies, the public, other engineers, other planners, and the list goes on.  When all constituents are brought together to create a plan, it works – from operators in a plant to community leaders.

Water recycling is not new to our field but how we evolve it and talk about it can change how it is perceived and how we develop communities.  Water preservation is Valentine’s sole purpose, and a future of pure water is our vision.

Laundry washing units for water recycling

Laundry washing units

Laundry water treatment

Laundry water treatment

One example of the impact water recycling can have is Valentine’s water recycling projects with Corrections Corporation of America.  They utilize laundry water recycling which reduced water consumption by 80-90%, and shower water recycling for toilet flushing which reduced potable water demand by over 70%.  See the complete case study.


Teresa.Valentine at ADEQ brown bag

Teresa.Valentine at ADEQ brown bag

Walking The Talk

Arizona Department of Environmental Quality (ADEQ) welcomed Teresa Valentine to speak at a Water Quality Division brown bag with ADEQ employees about incorporating green technologies into water and wastewater treatment. The topics of conversation that were of most interest included innovative processes being used to reduce odors at wastewater treatment plants and how gray water recycling techniques have been used to greatly reduce the amount of water being used at the Eloy Detention Center.  Other energy and water saving innovations discussed were turbo blower technologies and hydroturbine projects.  We send out a big thank you to Chuck Graf, Senior Hydrologist at ADEQ for the invitation.

To learn more about these technologies, please visit our Case Studies or contact Teresa at tvalentine@valentineengineers.com.


During Science Week at a summer camp in Seattle, the kids learned all about water conservation and then went online to do their own research.  They came across the Valentine website and our Resource Page which has a section dedicated specifically to educational resources for youth or anyone interested in gaining more knowledge about the environment.  The students and their teacher wrote us a nice letter thanking us for the information and expressed how useful it was to them while they were learning all about water conservation and the environment.

The kids made a special request to add another page for our visitors to enjoy and we agree that it offers great tips for saving water:

“How to Conserve Water in the Bathroom” – http://www.bathroomremodel.com/how-to-conserve-water-in-the-bathroom/ 

It’s so important for all of us to better understand what is happening with our environment and how we can protect it.  A very big thank you to the kids and their teacher, Francesca Davis, for their great suggestion to add more great resources to our Resource Page

If you have creative ideas for our resource page, Teresa would love to hear from you at tvalentine@valentineengineers.com.


City of Mesa SEWRP Turbo Blowers

City of Mesa SEWRP Turbo Blowers

Municipal water and wastewater plants, pumps, and lift stations can consume more than 40% of a city’s energy in a year to distribute, disinfect, treat, and pump water for their customers.  The City of Mesa realized this and took action to make improvements to their systems.

The City of Mesa Southeast Water Reclamation Plant (SEWRP) aeration improvements project represents a unique application of different technologies brought together to achieve two main goals; reduce energy use and optimize aeration and process control in the activated sludge process. The different technologies installed at the Mesa SEWRP include fine bubble aeration, high speed turbo blowers, and real time analyzers for nutrients (ammonia and nitrate) and dissolved oxygen.  The blend of these technologies as well as the cutting edge high speed turbo blower technology is a unique application in the State of Arizona.

Collectively, the turbo blowers and the fine bubble aeration saved the city more than 2 million kilowatt-hours annually which equates to more than 60% savings in energy use, or approximate $166,000.  Check out City of Mesa video and learn about their SRP rebates.

The heart of this unique aeration system is the high speed turbo blower.  The new high speed turbo blowers (200hp) provide additional 30% energy efficiency over the existing centrifugal blower (400hp) technology due to several key benefits of this cutting edge technology.  The benefits include:

  • Lower installed motor horse power (HP) due to a more efficient blower design
  • Efficient blower design components include the direct drive impeller to motor configuration coupled with an air bearing design and the more efficient permanent magnetic synchronous motor
  • Up to 40% turndown capability due to variable frequency drive

Like many WRPs, the Mesa SEWRP experiences diurnal swings in influent flow and loading.  A conventional aeration system consisting of constant speed centrifugal blowers, dissolved oxygen analyzers and modulating or manually operated airflow control valves is typically utilized and was the original method installed at the facility.  The conventional system has two main shortcomings, limited ability for airflow turndown on centrifugal blower, and thus limited ability to optimize energy consumption and process control. Furthermore it lacked the partial optimization of energy use and process control that can be realized with dissolved oxygen only control.

Due to the shortcomings of the existing aeration system, the Mesa staff at the SEWRP found the existing centrifugal blowers to be limited in their turndown capabilities, resulting in high devolved oxygen (DO) concentrations during low flows and forcing staff to blow off air excess to maintain DO concentrations.  The generally higher DO concentrations consequently also increase the DO concentration in the anoxic zone due to internal mixed liquor return flows, resulting in inefficient nitrogen removal.  Mesa operations staff had devised an interim control strategy for inlet valve modulation which achieved some turndown, but it could not provide significant energy savings.

The combination of fine bubble aeration, high speed turbo blowers, and both dissolved oxygen and nutrient analyzers offers a combined solution that optimized energy use while at the same time improved process control.  The fine bubble aeration alone has resulted in approximately 30% greater oxygen transfer efficiency over the existing coarse bubble diffusers.  The fine bubblers were designed with a tapered heads allowing for minimal transfer of oxygen from final aerated zone back to the anoxic zone.

Although fine bubble aeration is not a new technology, coupling it with nutrient/DO controls provided for a unique application with this project.  The fine bubble aeration control valves at each of the aeration basin zones will now modulate and control both the DO set point and an overriding ammonia set point.  Thus, even when the optimum DO requirement is met and ammonia set point indicates treatment to be complete, the control strategy will further decrease the DO set point to further optimize energy usage.

In addition to the energy, control and technology benefits, the high speed turbo blowers required less overall maintenance than conventional blowers and operate at a significantly reduced noise level.  The operational noise is a real added tangible benefit for plant staff that has to work in close proximity with the system on a daily basis.

Bringing together new technologies and blending it with various applications has provided the City of Mesa with an innovative solution to accomplish major financial and operational goals.  The techniques that have now been applied provide a significant energy savings which reduces overall operational costs and CO2 emissions.  This project has been a great example of how technology and the use of variable control techniques in the application of that technology can solve many of our greatest wastewater challenges.


Hydro Turbines - Energy Recovery

Hydro Turbines for Energy Recovery

The process of delivering water from the treatment plant to the customer requires a significant amount of hydraulic energy. In the process of water delivery, excess pressure often needs to be reduced or is wasted. Pressure reducing valves (PRVS), atmospheric discharge, or excessive hydraulic head are commonplace. Reclaimed water and raw water delivery systems also experience similar hydraulic conditions. This hydraulic energy can be captured with the use of hydro turbines.

How it works

As with a PRV, a hydropower turbine reduces pressure. Instead of dissipating this excess energy like a PRV, however, the turbine converts it to usable power. A pump can be operated as a turbine, referred to as “pump as turbine” or PAT, but it is not as efficient as a classical hydro turbine such as the francis-type turbine (see picture). For free discharge, a pelton or turgo type turbine is recommended with the pelton turbine most effective at high head applications. To determine the best turbine for an application and the subsequent expected return on investment, a good understanding of flow and pressure characteristics and site conditions is required.

Where to use

In many Cities throughout the Phoenix area, there are numerous examples of electrical energy that can be garnered from wasted hydraulic energy: 1) PRVs, 2) Free discharge to reservoirs, 3) Recharge wells, 4) RO brine discharge, 5) low head-high flow raw water intake, and 6) CAP/SRP canal systems.

Valentine is currently performing a study for the City of Scottsdale to investigate the use of hydro turbines within their water system.



40% REDUCTION in energy costs


Energy Savings with Turbo Blower Technology



  • 40% REDUCTION in energy costs
  • NO noise
  • SMALL footprint
  • MINIMAL Maintenance

The typical WWTP uses 40% of its overall energy consumption in its aeration process. Positive displacement or multistage centrifugal blowers are two technologies that are utilized for process aeration. These technologies, while proven, are energy intensive. These technologies are also noise and maintenance intensive.

Valentine Environmental Engineers designed the expansion and upgrades to the Arizona American Water Company Wishing Well Water Reclamation Facility (AAWC). The facility was equipped with a small blower room and conventional blower technology. The WRF aeration capacity was being doubled but the available space did not increase. The new conventional blowers to meet the increased capacity could not fit in the building, exceeded available electrical supply and would require HVAC modifications to the building to evacuate the additional heat load from the new, larger conventional blowers.

Valentine and AAWC investigated the problem from all angles and the challenges presented to determine the best use of space and more modern technology.

Case Study: Arizona American Water Company Wishing Well WRF

The Solution

The dawn of the Turbo Blower Technology has revolutionized the process air blower supply for WWTPs. Turbo blowers are not only quiet and require a small footprint, they are more efficient than conventional blowers and offer greater turndown capabilities.

Turbo blower technology has its roots from the aviation and aerospace industry. This technology relies on an air foil bearing supported on a shaft that is directly integrated with the variable frequency drive, motor and control system in a single enclosure. The air foil bearing eliminates friction between the bearing and the shaft and thus improves the efficiency of the blower while allowing 40% turndown capability.

Success with the Turbo Blower Technology

Valentine and AAWC investigated the Turbo Blower Technology to resolve all of the project issues:

  • Ability to install turbo blowers in existing space without having to expand the building
  • No requirement for additional electrical power due to the efficiency of the units and requires less installed hp overall
  • No HVAC retrofits required as blowers produce virtually no heat and can function at temperatures of 120 F

The blowers reduced overall construction and operations costs. Turbo Blower Technology is significantly more efficient than conventional blowers. You will save on energy costs, decrease noise, reduce your footprint and reduce your maintenance costs with newer methods.

Other turbo blower retrofits that Valentine Environmental Engineers designed:

  • Corrections Corporation of America Eloy Detention Center – three new 50 hp blowers
  • City of Scottsdale Gainey Ranch – replacing three existing 75 hp blowers with three new 50 hp turbo blowers, 6.7 year payback, $50,000 annual energy savings
  • City of Scottsdale Water Campus – replacing two existing 400 hp blowers with three new 250 hp blowers, 3.4 year payback, $200,000 annual energy savings
  • Other projects in the design phase for City of Tempe and City of Peoria


Blower Energy Audits performed by Valentine Environmental Engineers at local WWTPs are continuing to prove successful from both an energy savings and rebate perspective for local municipalities.  Valentine has performed or is in the process of performing upgrades of the centrifugal blowers at four major WWTP facilities in the Phoenix area.

The blower technology will be upgraded to high speed air bearing turbo blowers and is estimated to realize nearly $1M annually in energy savings and garner over $700,000 in one time rebates from SRP and APS.

For more information on these projects see the Projects List or Energy Audits area of our website or call Teresa Valentine at 480-283-8991.


Valentine Environmental Engineers recently acquired the first grey water permit in the state of Arizona for laundry water recycling. This innovative package treatment technology, manufactured by AquaRecycle, treats the laundry discharge and recycles it back to the washing unit for use in the next washing cycle.

Water savings of 60 to 85% are realized along with energy reduction benefits. The laundry recycling will be utilized in local prison facilities with a total savings of over 40,000 gallons per day or 14.6 MG annually.

For more information on the laundry recycling technology visit www.aquarecycle.com or call Teresa Valentine at 480-283-8991.