Enabling Lean Water Operations: Transforming Data Into Information is Critical for Driving Efficiency for Rene wable Water Resources (ReWa) Randy Boyette, Senior Process Control Officer, Renewable Water Resources Chuck Scholpp, Director IIM Business Unit, Hach Gabi Miles, IIM Product Manager, Hach

ABSTRACT

Today, the water/wastewater industry faces many challenges. Budgets are tight and regulations are constantly changing. More than 60 percent of the workforce is expected to retire in the next four years, meaning decades of knowledge retention will need to be passed on to the next generation of water/wastewater ope rators. Additionally, not only ar e we seeing the need for more and more data collection, but also analysis of cr itical data, which has led to information overload. With all of these challenges taken into consid eration, data collection n eeds to be simplified.

In line with WEF’s Five Principles and Ten A ttributes of Effectivel y Managed Water Sector Utilities, implementing a lean organization for the water/wastewater industry supports these basic tenets and helps organiza tions address the growing challe nges they are facing regarding constant change, reduced budge ts and increasing regulations

. Taking a lean approach to the water industry provides utility managers with a clear roadmap for how to improve their organization-wide performance. “Lean” is a concep t that applies to every business and process. Essentially, it is a methodology to help deal with constant change. For the water/wastewater industry, going lean means automating processes, utilizing technology and ultimately, optimizing

the business.

Renewable Water Resources (ReWa) brings a real world example of how the early stages of implementing a lean operation is beginning to have a major impact on the water utility’s operating efficiencies.

ReWa realized significant benefits by embraci ng lean concepts. Findings to date include:

 Facility savings of as much as $232,000 a year in solids management and chemical usage

 Savings of over 200 hours per year on pla nning and travel the various facilities

 Facilitates close monitoring of aging equipment, allowing better preventive maintenance, reducing costs and increasing efficiency

 Supports decision making and improves the budgeting process

 Provides accurate data for constr uction and optimization projects

 Reduces the learning curve for bringing new ope rators up-to-speed, k eeping skillsets sharp

KEYWORDS

Lean operations, efficiency, water/wastewat er, data management, water information management, Hach, ReWa

INTRODUCTIONIn today’s economy, finding ways to “do more with less” extends to virtually every business, government and education institution. Plain and s imple, the days of “business as usual” are a thing of the past as economic and social pre ssures mandate more effi ciency, accountability and performance. The water and wast ewater industry has greatly im proved its own performance and the value delivered to communities by adopting lean principles – by leveraging new technology and processes to modernize the industry. This paper outlines four tips and a case study to illustrate lean principles that water and wastewat er facilities can incorporate into their daily operations to “do more with less” in the f ace of ever-changing regulations and tight budget

constraints.

Renewable Water Resources (ReWa), located in Greenville, South Carolina, is embracing lean concepts and has realized real savings and e fficiency gains across the organization. ReWa currently operates nine wastewater treatment pl ants and one of the S outheast’s largest liquid biosolids land application program. ReWa has deve loped a solid, 20-year st rategic plan that is reviewed regularly and provides fo r efficient utility operation. Employee safety and Zero NonCompliance are top priorities at ReWa.

This paper outlines Lean concepts, four actionable tips for Lean Operations and how they are applied at ReWa to achieve effici encies and sustainable results.

 Taking a holistic approach to operations

 Creating a lean culture

 Automating manual processes

 Achieving lean sustainability

TAKING A LEAN APPROACH

The Lean Institute points out: “Lean applies in every business and every process. It is not a tactic or a cost reduction program, but a way of thinki ng and acting for an entire organization.” The fundamental concept is to systematically identify and eliminate wasteful elements in processes until an organization is executing its purpose at th e highest level possible. When that happens, greater value is created for the customer, the pr ocesses within the organization are optimized and the people running the processes are aligned with actions that enable them to continually deliver what’s most important.

Looking specifically at the water and wastew ater industry there ar e many challenges and opportunities for lean thinking to have a pos itive impact on operations. Not surprising, budget constraints, with a public that is highly resistant to rate in creases and facilities increasingly expected to do more with less, is a big concern. Adapting to th e ever-changing regulations poses the risk of fines, citizen complaints, reputation, or worse, environmental impact or public health. Within the workplace, knowledge retention is a main concern as an aging workforce prepares to retire. More data is being generated and empl oyees are being asked to make the difficult transition from being collectors and reporters of data to bein g data analysts and knowledge

workers.

The need to achieve higher efficiencies and reduce operational inaccuracies is driving positive changes in how water and wastewater treatmen t utilities operate. Embr acing lean and supportinglean thinking with new technologies and methods is helping facilities meet these goals and cope with the many challenges that they face. The f undamental concept of Lean Operations is to systematically identify inefficiencies and put more focus on improving th e overall value of the

system.

THE CASE FOR LEAN OPERATIONS

There are numerous ongoing issues that impact wa ter and wastewater utilit ies but, according to AWWA’s State of the Industry Report 2010, busin ess issues are the most pressing challenges that they face. Simply stated – the cost of ope rations continues to increase while rates remain flat. Meanwhile, capital investment into rehabili tation and new infrastructure is not keeping pace with current and projected demands.

In addition, complying with increasing federal a nd state regulations is financially burdensome. The legacy approaches taken to monitor and docum ent the treatment processes can be inefficient and inaccurate. Relying on labor-intensive, manua l data logging contributes to violations, subsequent fines and expensive-to-impleme nt process changes. Compounding the costs associated with compliance is the increasing pub lic awareness of drinki ng water quality issues, ranging from upstream discharge fro m wastewater facilitie s into pristine waterways to the chance of pharmaceuticals and metals seeping into wate r supplies, which of course leads to more requirements and the added burden of addressing them.

Another industry issue that is looming is th e “brain drain” as long-time employees, who constitute the bulk of the workforce, near re tirement. It is estimated that the number of employees currently active, yet at retirement ag e, is close to 200,000. Wh ile this large group of seasoned professionals is currently delaying their departure from the workplace, because

retirement funds have been reduced and the econo my is unstable, a positi ve shift in the economy will compel them to eventually move into reti rement. When that happens, the challenge of replacing them and preserving the k nowledge they posse ss, will swell.

To meet these challenges, water and wastewater utilities need to l ook for efficiencies in treatment processes and business management. Lean principles need to be continually evaluated and applied. As in other industr ies, lean principles and techno logies that help optimize and automate the business can be integrated to create a platform for dealing with constant change.

BECOMING A LEAN OPERATION

What does the water/wastewater utility customer want? The Lean Operations process starts with realizing that water and wastewater customers want the highest quality product at the lowest prices. For this industry it is re latively easy to define: provide total customer and community

value – which in Lean terms is the purpose – while overcoming the challenges previously described. The four principles of Lean Operatio ns provide opportunity as well as challenges for the industry.1. Taking a holistic approach to operations In a Lean Operation every person, resource and process within the plant is dependent upon one another and should be managed in unison. Achievi ng Lean Operations calls for identifying each point in the process, assessing it to determine if it is necessary and then deciding what action needs to be taken to optimize that point for maximu m value at the lowest cost. Identifying all the steps in the value stream and eliminating unnecess ary steps that do not crea te value is part of looking at the processes with a lean perspective.

Technology can be leveraged in the overall assessment of op erations, to complement the knowledge that operators have and the observations that they make. Team s may want to gather and analyze data across the uti lity, from operations and field da ta to lab results. Consider including third-party back-office systems associ ated with accounting, GIS, weather service, pretreatment and CMMS software to complete the picture. This centralized view of enterprisewide data is a central element to increased collaboration across departments and functions, and helps facilitate a collective mindset and decision-ma king process that leads to the elimination of wasteful practices and promotes a leaner, more efficient operation.

A related component of lean thinking is: Make the value-creating steps occur in tight sequence so the product will flow smoothly toward the cust omer. It’s important to keep in mind that what the service utilities prov ide is a product. And, ensuring that the product is available as needed, with the right quality and at the lowest cost possible, is realiz ed through continual monitoring of the processes and equipment. When operators k now what is happening throughout the plant, they can use diagnostics to keep a ssets functional, anticipate pr oblems, schedule preventive maintenance, eliminate downtime and look for opportunities to optimize operations. What’s new here is the ability to see the big picture; that perspective creates the ability to more proactively marshal operations.

Applying a holistic approach does not need to be a big-bang transformation. Water and wastewater utilities can start small by having facility, operations, managers and back-office staffers attend meetings associated with busin ess, operations and res ource allocation. Have managers rotate through facility, maintenance an d operations departments to experience day-today practices that are either wo rking or not working. Provide repor ts with operational, workflow,

asset allocation and field and lab data in dashboa rd-view in a central meeting area. And, provide visibility and the opportunity to share suggestions and ideas th at will lead to continuous improvement. These steps will help establish a culture of lean, where effective problem solving and continuous improvement can take root.

2. Creating a Culture of Lean Improving processes and harnessing the power of t echnology is only part of the Lean Operations equation. Much of the success of lean comes from cultural changes that encourage openness, the freedom to question the status quo and a willingness to reflect on the past as a means of instituting new ideas that will improve future performance. The goal of Lean is to open up the work process and abolish the usual hierarch ies, thereby empowering each and every team member, regardless of “rank,” to have input on issues large and small.A key principle of lean is to “speak with da ta.” Therefore, technol ogy that enhances data

collection and communication must be used to transform the disp arate data points into useable and impactful information that can drive sound d ecisions. The days in which years of operator experience traditionally was requisite to performi ng the job needs to morph into a science-based process. A utility can use the data to prove to th ose resistant to change that eliminating wasteful steps in a process or making other changes will ultimately benefit the organization and, consequently, them.

3. Automating manual processes Supplanting manual data collection in the field and the facility with computer-based data gathering, communication and anal ysis is a prime example of how automation can improve technician productivity and business management . Equipment suppliers, software vendors and even the EPA are all moving to integrate and auto mate the data gatheri ng, reporting and sharing lifecycle. Water and wastewater operators should take it upon themselves to learn, reach and become an active participant in the developmen t and adoption of new t echnologies that replace and enhance tried and true manual process that worked for years, but are no longer viable.

Today, utilities can gather and show visibility into the entire sy stem, and feed data back into operations, asset management, supply purchas ing and equipment maintenance operations. Superior data collection and commu nication drastically cuts time lo st by operators – letting them focus on running the plant. Utilizing auto mation afforded through technology provides actionable data that can help quickly create regulatory and business reports, and improve operational efficiencies.

4. Achieving Lean sustainability Constant change is part of lean, just as it is part of the water/wa stewater treatment industry. Lean Operations calls for its own form of sustainability – by revisiting lean processes again and again, and improving them on an ongoing basis. It is th e concept of “Plan-Do-Check-Act” framework. This concept mirrors the philosophy that is in spiring industry leader s to implement lean approaches and to create an organizational cult ure that embraces the notion of change and is committed to continuous improvement. Combini ng lean thinking with the advantages of automation, visibility, accuracy, improved analytics and the ability to real ize a holistic approach to operations is helping utilities provide th e highest quality of community service while improving efficiencies and fiscal performance.

Wringing more efficiency out of already well-functioning operations depends on having access to and leveraging reports, visual graphs, da shboards and other resources as a means of establishing a data-driven decisi on making process. New technology is available to allow for the visual management of metrics, and business in telligence solutions are emerging for improved visibility, both at the high le vel and down to a focus on a sing le device, making it possible to more effectively extend lean pr inciples across the organization.

Managing water, as well as the resources and facil ities that treat it throughout both the water and wastewater lifecycle, makes “sustainability” a cr ucial component of the ov erall Lean Operations

mix.LEAN OPERATIONS IN ACTION: ReWa - A REAL WORLD EXAMPLE

Renewable Water Resources (ReWa), located in Greenville, South Carolina, currently operates nine wastewater treatment plants and one of the Southeast’s largest liquid biosolids land application program. Providing water reclamation to more than 400,000 people in five counties, its service area spans 296 square miles and includes three river basins. ReWa releases treated water at the headwaters of the Reedy and Sal uda rivers, and into Du rbin Creek. ReWa has developed a solid, 20-year strategi c plan that is reviewed regu larly and provides for efficient utility operation. The plan incorporates in cludes a holistic approach and provides more transparency across the organization to allo w for “leaner” operations and to continuously streamline operations.

Business Situation

 ReWa was an early adopter of data management software. In 1989, the Durbin Creek Facility purchased its first personal computer and prot otype data management software designed for water and wastewater monitoring. This early ve rsion allowed the plant to store up to six months of data in a single location; develop complex equatio ns to monitor Mixed Liquor Suspended Solids (MLSS) and to graphically view data.

 The success of the Durbin Creek solution led to a networked implementation at the Mauldin Road Facility in 1995. The data analysis was st ill limited to a single plant, but allowed better access for facility personnel and its support groups.

 In 2003, the software was installed at each treat ment plant. While improving the quality of the individual operations by automating and streamlining data entry and having data available locally, it was difficult to share information and to maintain consistency across all of the treatment plants. As a work-around to getting a complete picture, ReWa used spreadsheets to collect the data from each facil ity. This meant travel was required to each site to gather the information, causing delays in da ta availability and introducing data errors. Information Systems staff struggled to manage multiple versions of software which included multiple links to SCADA systems, multiple installations and multiple software updates/upgrades as well as ma intaining large spreadsheets.

Blake Visin, director of Information Services

, discussed another repercussi on: “Historical data is essential to optimized daily operations. I was co unting on operators to veri fy that the backup was complete and the data was safe. I often found myself wondering if we had adequate redundancy in place.”

Even though each plant had the capability to m onitor and track trends through WIMS, the full capacity of central management and optimi zation had not yet been fully realized.

Solution: Central Management of Data Makes it Sustainable

In order to solve the problem and build a multi- facility network, ReWa procured a standalone server for its central operations office. This central server hosts the data management software and acts as the primary location for ReWa’s da tabase, housing all the plant data and allowing remote access. The central server approach has si gnificant benefits, including increased security,easier backups and a database that everyone can access. The Information Technology department provides a Terminal Services approach, essentia lly giving all authorized users remote access to the data. Each facility or regional foreman can s ecurely log onto the system and check data or run reports. IT retains control over the network a nd license management, and updates are done

from the central location. Servers at the othe r facilities act as backup systems, providing the redundancy that prevents a single device failure from disrupting productivity.

ReWa implemented the centrally hosted networ k version of Water Information Management Solution (WIMS) throughout its facility network to:

 Drive efficiency and improve deci sion-making based on timely data

 Increase communication and unders tanding of operations by provi ding authorized users at all levels of the organization easy access to the data

 Increase the ability to automate reliable transm ission of accurate data to a central database

 Establish a secure backup and r ecovery contingency alternative

 Ensure a secure environment

The data management tool has improved insigh t into operations across all facilities and the system as a whole. Eleven years ago, ReWa incurred more than 100 NPDES permit noncompliance issues. This year, a ll facilities earned NACWA awar ds with four awards being platinum ratings for zero non-complia nce in the past five years.

WIMS enables ReWa to focus on compliance; po tentially saving the South Carolina counties it

serves hundreds of thousands of dollars. Non- compliance can be expensive. In addition to damaging the organization’s reputation in th e community, non-compliance could result in significant fines. The Department of Health and Environmental Control (DHEC) could put a moratorium on local building or a shutdown orde r on specific industries — the effect of which ripples out across the regional businesses.

Zero Non-Compliance

Named Zero Non-Compliance , ReWa’s approach to driving qu ality and success centers on a goal to prevent all compliance discrepancies. Randy B oyette, ReWa’s senior process control officer,

describes the shift that has occu rred within the organization. “ Zero Non-Compliance is a top priority preceded only by employee safety. We used to focus on money and budgeting. That’s changed. And as a result of focusing on opera tions, managing the budget has gotten easier.”

Given this initiative, Boyette as ked the question: "What tools can we use every day to show what problems we have?” In response, ReWa started build dashboards (F igure 1) that identify the key areas that plant operators need to monitor da ily. Alarms tied to those key indicators warn operators when any process data goes into the red. "We programmed those alarms especially for operators, so they can see where their problems ar e and quickly take measures to correct them,” said Boyette.Figure 1: Personalized dashboards provide fast access to information and allow monitoring of key performance indicators

Proactive Compliance and Pretreatment The pretreatment group also uses WIMS to spot tr ends within the data. M onitoring variations in phosphorus, ammonia and pH levels may provide an early indication of an influent problem. By getting timely data, the group can use WIMS to correlate information to specific industrial discharges. It can then work with the industries to identify potential sources and develop mutually beneficial solutions. WIMS reduces the amount of time the group would otherwise have to spend looking ac ross all industries.

Because data is stored in a secure database and is easily accessible, the compliance team can

work on the same data with the operations personnel to differen tiate simple outliers from real problems. With effortless access to WIMS data, the team is not reliant on operator availability to provide data for analysis.

Figure 2: TKN is a required parameter for regulatory reporting and helps to monitor plant operationsOptimized Operations

With compliance as the center focus of ReWa’s op erations, it might be e xpected that efficiency takes a back seat. But by having relevant, meaningful data at hand, operators can improve plant operations as well. IS Director Visin says, “Compliance is the dr iving factor. But with that under control, we can start looking at efficienci es." And ReWa has found ways to optimize.

Area managers used to spend at least two hours a day traveling to plants for status checks and operational information. Now, through persona lized dashboards, everyone can have quick access in minutes to needed data and input form s without incurring the time and cost of visiting the various sites as frequently.

Biosolids management, a critical part of the wa stewater treatment process, can be a costly operation for systems as large as ReWa. In the past, the Biosolids Manager had to call all the plants every morning and every afternoon to get all the tank levels and adjust transportation schedules. This simple task took roughly one-t o-two hours of the manager’s week. Using WIMS, which is connected to each plant, the Bios olids Manager can use a personalized dashboard (Figure 3) to see the tank levels across the entire system. The instant access to the live data allows the Biosolids Manager to invest time on the more critical tasks of quality control and

customer relations.

The ability to see trends across significant peri ods is especially important for managing tank levels and truck usage. Efficient biosolids dewate ring is essential for cost effective transportation and to meet the strict requirements for land ap plication or other methods of disposition. The Process Control department developed a WIMS entry sheet for the solids procedure at each plant. The process is designed to increase solids digestion and to help th icken biosolids. Using long-term trends, it was able to identify a dire ct correlation between current solids set points and the real output. By running test s several times a day and making “on the fly” adjustments, the

biosolids concentration was increased from three to four percent, which re sulted in a 20 percent reduction of the solids management budget; a $20 0,000 savings. As part of a pilot study, one facility will be experimenting w ith automatic solids meters in hopes of driving efficiency up to five percent. The solids management group is ab le to land apply their biosolids to nearly 9,000 acres of farmland, which is estimated to increase to nearly 11,000 acres in the near future.

Figure 3: Dashboards that monitor tank le vels save time and increase efficienciesFigure 4: Monitoring polymer usage is essential to efficient operations

Optimizing operations includes maintaining and repl acing equipment. In the past, operators at the plant would put in an orde r for equipment maintenance. Of ten, the maintenance team would inspect the equipment and determine that the e quipment was within operational specifications, contrary to what the operators observed. Using WIMS, operators now can provide the maintenance team with long-term trend data sh owing that efficiency has dropped as equipment has aged. This data shows the return on invest ment of replacing aging equipment as well as performing preventative and routine maintenance.

Improved Finance and Budgeting Pr ocesses – “Speak with Data”

Managing the finances across multiple facilities ca n be a daunting task. In the past, yearly budget reports took each plant days to complete. The task required them to sort through pages of data,

calculations and costs for the curr ent year. Historical data was t oo difficult to obtain and factor in. Kevin James, east division manager, explai ned the benefits of using WIMS to track operational costs: "Before, we us ed Excel spreadsheets, one for each month. Now, instead of the tedious and potentially inaccurate exercise of manually reviewing spreadsheets every 30 days, we can just run a report." Using WIMS, they cr eate automatically populated entry sheets for every plant that show all expenditures in real -time. In contrast, the finance department sometimes took over a month when getting expenditu re information back to the plant. Using the real-time data, operators can make informed d ecisions. Having timely data also allows plant managers to track trends, plan budgets and make operational decisions wi th the confidence of knowing that they have accurate data.

Plant managers now can develop budgets w ith actual data. The conversations around budget needs are fact-based versus relying on suppos ition and instinct. Mana gers can examine budget spreadsheets, identify adverse trends, and formul ate in-depth root cause analysis. Solutions can be quickly devised by analyzing long-term tre nds and comparing them to current parameter deviations. For a single plan t, trends that go unmanaged can quickly cost $5,000-$10,000 inmisused chemicals. Magnifying those costs across eight plants can suddenly result in serious budget issues.

David Skyles, the Lower Reedy plant foreman, e xplains the value of watching chemical usage through WIMS on a daily basis. “By monitoring actual use of chemicals, like lime, we can identify usage that is out of the norm and adjust quickly. By doing just that, I can save as much as $32,000 a year with minimal effort."

WIMS gives Skyles the high-level perspec tive he needs to manage overall quality assurance/quality control (QAQC). "We can QAQC the plant quickly and see something immediately out of whack. It tells us if we either have a process that’s not within specification, have equipment running poorly, or a little bit of human error.” Gilder /Durbin Plant Foreman David Collyer agrees

. “And more than one person has the ability to look at it. The more eyes that review the data, the more likely we are to catch an error.”

This streamlined access to performance data is saving ReWa at least 20 hours per plant, or roughly 200 hours per year, in budget reporting alone. And the savings aren’t just for time spent budgeting. Operators also benefit by having historical data that they can reflect on annually to see the year-over-year seasonal variations and ma ke process adjustments to compensate. This type of analysis was nearly impossible prior to the easy availability of long-term data.

Accurate Data Drives Efficiency

In a pilot study, ReWa is monitoring digester expe riments in an attempt to create more methane. By identifying how much gas can be created under alternative scenarios, it can determine the size of the methane-fueled combined heat and power (CHP) generators it will be building for the plant.

At one of the plants involved in the pilot, a gas flow meter was malfunctioning and entered an incorrect reading into the database. Using WIMS, the facilities foreman was able to identify the incorrect data using two months of data. The en gineers building the CHP generators must have exact measurements or the generators will be built out of spec. The erroneous data would have resulted in an undersized CHP generator.

Consultant and engineering firm requests for da ta are common. Fulfilling such requests for data ranges of six months to 10 years can be a daunt ing task. Boyette says that now he can respond

while the consultants are still on the phone. It is a capability th at saves Process Control team members, like Boyette, si gnificant amounts of time.

“That historic data is critical from an engi neering perspective when we are considering an upgrade or change in process. I can't estimate th e physical time it would take to pull that history otherwise,” Boyette sa id. Money also can be saved by engaging the engineering firms judiciously. Having easily accessible data not only saves time, it allows ReWa to set up their own studies, saving engineering costs.

Improved TrainingThe ReWa Process Control group also uses WIMS fo r training plant operato rs. The efficient tool inspires the new operators to ta ke the initiative to look at the data and get insight into the operations and trends that are a ffecting the plant. The Process Control group travels once a year to provide advanced WIMS training that helps ea ch facility learn how to use the tools more effectively. Using WIMS, operator and facility personnel training is provided monthly to keep skillsets sharp. Using the visual tools in WIMS, tr ends and correlations can easily be laid out for new trainees so that they can quickly s ee plant operating levels and history.

Collier sums up, “I think it speeds up the learning process greatly. WIMS helps trainees look at raw data, manipulate it, and be proactive. Because th ey can see it, they lear n much faster. It's not just a set of data points. It gi ves meaning to the data points. And, it gives them a way to apply the

data.”

Results

 Facility savings of as much as $200,000 a year in solids management

 Facility savings of as much as $32,000 a year in chemical usage

 Reduces solids management planning time by one-to-two hours a week

 Cuts as much as 100 hours per year of time on the road for area managers and the Process Control team and enables better plant performance management

 Facilitates close monitoring of aging equipment, allowing better preventive maintenance, reducing costs and increasing efficiency

 Supports decision making and improves the budgeting process

 Reduces the amount of time needed to respond to engineering firms and consultants – from days to minutes

 Provides accurate data for constr uction and optimization projects

 Reduces the learning curve for bringing new ope rators up-to-speed, k eeping skillsets sharp

CONCLUSION

The progress made at both the managerial and oper ational level within our industry is significant and continues to advance. The concepts within Lean Operations build upon that progress as illustrated by the work being done at ReWa and elsewhere, and provide an outline for revisiting and adjusting the improvement processes contin uously, and to use automation technology to drive holistic improvements th roughout the organization. Lean Operations for water and wastewater is intended to help utilities drive ev en more efficiencies from day-to-day operations, while creating the “lean sustainability” to delive r the highest level of se rvice over the long haul. Its central concern is minimizing inefficient efforts and resources, and to leverage new technology and processes to modernize the indust ry. ReWa is realizing the impact such an approach can have on fulfilling its mission of pr oviding comprehensive, sustainable water and wastewater management solutions that promot es public, economic and environmental health.

REFERENCES