Reservoir Management Discussion: SNWA + Anglian Water

Anglian Water requested a meeting with the Southern Nevada Water Authority to share knowledge and best practices around reservoir management.  Specific topics (and the corresponding time stamp in the video) included:

  • Online Water Quality Monitoring Efforts (9:55) – presented by Todd Tietjen, Ph.D, Regional Water Quality/Research & Development, SNWA
  • Remote Inspections (34:47) – presented by Ryan Benner, Sr. Maintenance Engineer, Asset Mgmt Division, LVVWD/SNWA
  • Reservoir Repair and Maintenance (53:07) – presented by Matthew Brems, Manager, Maintenance Engineering, LVVWD/SNWA
  • Water Quality Monitoring in the Distribution System (1:08) – presented by Mao Fang, Sr. Civil Engineer, LVVWD/SNWA
  • Pipeline Risk Assessment for Capital Improvement Planning (2:02) – presented by Roger Jordan, Sr. Civil Engineer, LVVWD/SNWA

Thank you to everyone that participated and to Mike Dishari, Director of Infrastructure Management at LVVWD/SNWA, for coordinating the content. Please send questions to rebecca.shanahan@waterstart.com or feel free to contact a participant directly.

 

AM-TEAM: An Evaluation of Finished Water Reservoir Mixing Conditions

The Issue

The Metropolitan Water District of Southern California (MWD) was investigating options to enhance mixing and minimize short-circuiting within the Finished Water Reservoirs (FWRs) at the Joseph Jensen Water Treatment Plant (Jensen). The objective for this specific project was to provide a better understanding of mixing conditions and identify potential options for modifying the reservoir inlet design at the Jensen plant’s FWR Nos.1 and 2 to minimize chloramine decay and nitrification potential under various flow conditions.

The Solution

AM-TEAM applied Computational Fluid Dynamics (CFD) simulation and biokinetic modeling to assess current mixing conditions in Jensen’s reservoirs and to evaluate potential options for modifying the reservoir inlet design that minimizes short-circuiting within the reservoir.

The Pilot

MWD, with funding support from WaterStart, conducted a CFD study of the Jensen FWRs.  The pilot consisted of modelling the two FWRs at high flow (250 MGD) and low flow (60 MGD).  These flow rates were selected based on historical flow data from 2012 through 2017.  Although the capacity and the flow through each reservoir are similar, their configurations are different.  FWR No. 1 has a baffle wall at the inlet while FWR No. 2 does not.  Additionally, each reservoir has different inlet and outlet configurations and locations. Total project costs amounted to $48,000. WaterStart contributed $25,000.

The Results

Through CFD simulations and analysis, it was determined that the baffle wall at the entrance of the FWR No. 1 provides adequate mixing and allows a plug flow condition through the FWR No. 1 under various flows.  On the contrary, the absence of the baffle wall at the inlet and the location of the outlet of FWR No.2 create a region where water tends to circulate, resulting in higher water age.  Higher water age can contribute to chloramine decay and nitrification.  The regions with high water age within FWR No. 2 were present in both high and low flow conditions.  Through CFD analysis, it was determined that with appropriate modifications, the mixing conditions and the overall detention time in FWR No. 2  can be improved.  CFD allowed the analysis of the mixing conditions under various flows and the evaluation of potential improvement options without making operational changes and requiring actual modifications to the reservoirs.

See animation of tracer concentration!

Further Development

Metropolitan will use the results from the CFD analysis to determine the best option to enhance the mixing condition within FWR No. 2. Furthermore, FWR No. 1 was determined to be effective in its existing configuration; and therefore, no capital funds will be lost due to trial-and-error methodologies being applied.

About AM-TEAM

AM-TEAM provides advanced modelling services based on a unique combination of computational fluid dynamics capabilities and in-depth process knowledge.  The realistic 3D process models allow fast visual troubleshooting, virtual piloting, and virtual testing of solutions offering an alternative to onsite trialing.  AM-TEAM is specialized in multiphase CFD simulation, combined with water treatment process understanding and in-house developed process kinetic models.   Visit https://www.am-team.com to learn more.

KETOS- Continuous Advanced Water Monitoring for Arsenic

The Issue

The Southern Nevada Water Authority (SNWA) manages the water treatment and distribution system for the small community of Searchlight, Nevada. This system is over 50 miles away from the main operations center in Las Vegas.  The wells in Searchlight produce water that contains arsenic and therefore require an arsenic-removing ion exchange process to assure that only high-quality, potable water is being served to the Searchlight community.  The system is made up for two arsenic canister contactors.  These canisters must be monitored for arsenic breakthrough so that regeneration of the media can be scheduled and performed.  This is a timely process requiring an operator to travel the fifty miles to the remote location, collect a water sample, and return to the laboratory for analysis to determine if adjustments are required.

The Solution

SNWA, through WaterStart, discovered the KETOS Fabric Shield, now referred to as the KETOS Smart Water Intelligence Platform.   KETOS Shield Fabric delivers actionable insights and early warnings with predictive intelligence through real-time and on-demand monitoring of several ionic, environmental, water health parameters, amongst other contaminants at lab precision levels of accuracy on a continuous basis.  KETOS solution offering of proprietary, patented hardware with a secure connectivity framework and a robust interactive platform allows customers to have mission-critical water metrics proactively at their fingertips to drive a significant impact in their core-business and public health.

The Pilot

Recognizing that this technology had the potential to significantly reduce the required number of grab samples and yield operational intelligence for both SNWA and the Las Vegas Valley Water District in addressing rapid water quality changes at multiple organizational assets, the pilot was divided into two stages. WaterStart and the Southern Nevada Water Authority each funded $27,700 (USD) to KETOS for the piloting of two KETOS Shield units, one for each phase of the pilot. The pilot began in July 2019.

The primary stage was to install a KETOS Shield unit within the STAR Laboratory at the Alfred Merritt Smith Water Treatment Facility (AMS) located at Lake Mead. The KETOS Unit was tested with grab

sample comparisons for basic water quality parameters made between the compliance laboratory and the KETOS Shield unit.

The second stage was to install a KETOS Shield unit at the arsenic ion exchange facility in Searchlight for comparison between the unit and the compliance laboratory for arsenic measurements.

The Results

The system in the lab was monitored for several physical parameters like pH, EC, TDS, Salinity, DO and temperature at a 60sec level continuously while Nitrates was measured on an hourly basis as a scheduled test. Several other inorganics and heavy metals were also measured as desired. The arsenic levels at the Searchlight facility remain below or near the designed detection limit of the KETOS unit of 2ppb, so to date, at no fault of KETOS, there has been minimal arsenic to measure.  It has been determined by the SNWA research staff that the testing should continue to a point where partial arsenic breakthrough occurs in the contactor.  At that point, it will be determined whether the technology is useful in this type of operational environment.  Further, more testing is required to validate other heavy metal detection capabilities.

“Southern Nevada Water Authority is one of the foresighted utilities leveraging real-time intelligence for improving process controls and using KETOS advanced analytics towards their journey of digital transformation. Utilities around the country have a great model to replicate, learn and customize from to serve their needs in this new era of labor-free, cost efficient and CapEx free driven business models of accurate and affordable real-time monitoring”, Meena Sankaran, CEO, KETOS Inc.

“KETOS staff have been very proactive and responsive in ensuring their technology is able to meet the value propositions we’ve identified as an agency we’ve identified as an agency. It’s too bad that we did not see arsenic breakthrough align with historical trends but sometimes that’s how these pilots play out.  We look forward to continuing the work with KETOS and helping to prove out their technology. The benefits of a successful pilot outweigh the delay,” says Eric Dickenson, PhD, Water Quality Research & Development and Project Manager for SNWA.

Check out this video for more in-depth details on the Ketos project at SNWA.

Further Development

The system is capable of measuring 26 parameters autonomously that are remote controlled and offered as a fully integrated solution with the heavy metals, inorganics and nutrients of most interest compared to the other offerings in the Industry: lead, copper, cadmium, manganese, arsenic, chromium, nitrates, orthophosphates, calcium, hardness, free and residual chlorine, boron, silica, iron, and selenium. Mercury and Zinc will be available by end of Q1-2021. SNWA has signed up for another year’s subscription to continue the validation and use of this technology.  Even though the field application data is not complete, SNWA staff felt that this technology should be tested further at SWNA’s cost. Hence, adoption of this technology as a business-as-usual solution is under consideration.

About Ketos

KETOS, a water intelligence company was founded by Meena Sankaran in 2015.  KETOS delivers smarter, safer, and more sustainable water solutions to change the way the world thinks about water. This is done through a comprehensive offering of industrial-grade patented hardware, an IoT communication framework, and a robust software platform to address global water management issues. Real-time monitoring and understanding of water, both quantitatively and qualitatively, helps address both water efficiency (leak-detection & usage) and water quality (safety), ultimately increasing water availability. With the power of actionable and predictive water intelligence on a global scale, KETOS seeks to solve a number of the world’s water challenges with the goal of preserving this quintessential resource for generations to come. Learn more at www.ketos.co

microLAN

The Issue for the Drinking Water Industry

One of the most important issues for drinking water is ensuring public health protection against bacteria, viruses, and protozoan parasites. Particularly in finished drinking water, it is difficult to ensure the absence of these pathogens because of limitations with standard methods, particularly high detection limits and/or reliance on infrequent grab samples. Therefore, the existing regulatory framework allows drinking water utilities to focus on treatment process performance and monitor for indicator microorganisms, such as E. coli. Although E. coli are not necessarily pathogenic, their presence indicates that other pathogens might be present in the water, thereby representing a potentially higher risk to public health.

Drinking water utilities like SNWA routinely monitor for total coliform bacteria and E. coli to verify treatment process efficacy and ensure there are no spikes in bacteria that might indicate some other type of pathogen contamination. With standard methods, the time from sample collection to result ranges from 18 to 24 hours, which means that water might be delivered to consumers before a potential problem is detected. In the drinking water industry, the ability to speed up this process can help utilities identify and respond to potential contamination events more rapidly, thereby improving public health protection.

The Solution

SNWA looked to microLAN, an on-line sensor technology company from the Netherlands, to address this need. The company’s BACTcontrol technology has the potential to detect total coliform bacteria, E. coli, or total bacterial activity within hours, instead of the 18+ hours required for standard methods.

One of the most promising aspects of the BACTcontrol technology is that it relies on proven methods for bacterial detection that have been automated and equipped with sensitive detection capabilities to shorten analysis time. Traditional methods involve a similar approach but rely on the naked eye to detect changes, while the BACTcontrol employs a sensitive fluorescence detector. Because of this, small changes in color or fluorescence caused by bacterial activity can be detected with minutes to hours instead of nearly 24 hours.

microLAN currently has installations in Europe monitoring source water quality and treated drinking water. Although the existing applications are limited to Europe, similar drivers for the technology exist in the US, thereby indicating potential for broader deployment in the future.

Results of the Pilot

As part of the WaterStart funding, microLAN and SNWA collaborated with UNLV to conduct side-by-side bench-scale experiments with an independent spectrofluorometer, a BACTcontrol sensor, and the standard Colilert assay from IDEXX Laboratories, Inc. The team succeeded in developing a comprehensive understanding of the underlying detection mechanisms and in identifying several concerns related to the existing sensor technology. Most importantly, the sensor was unable to reliably detect total coliform bacteria and E. coli at low concentrations (i.e., excessive false negatives) and sometimes indicated ?hits? in the absence of the target bacteria (i.e., excessive false positives).

In drinking water applications, utilities are often dealing with “non-detect” situations so false positives are highly problematic from a compliance and operational perspective. Similarly, false negatives can have significant implications for public health. According to Daniel Gerrity, Associate Professor at UNLV and now Principal Laboratory Research Scientist at SNWA, “It was primarily a detection limit issue. The BACTcontrol sensor shows promise at higher concentrations, but the current technology is unable to provide reliable results at the levels typically observed in finished drinking water applications.”

Dr. Gerrity indicated that the BACTcontrol is currently a better fit for applications with higher levels of contamination. This might include monitoring recreational water quality, identifying bacterial spikes in agricultural irrigation applications, or possibly monitoring bacteriological water quality in impaired drinking water sources. The technology could be useful for establishing baseline bacteriological water quality and then identifying major spikes, although there would still be potential for false positive results.

“In principle, the microLAN technology has considerable promise because its underlying mechanisms are based off of traditional methods that are currently used to monitor for E. coli,” said Gerrity. “However, the technology still requires further refinement before it is ready for full-scale implementation in a finished drinking water setting.”

Further Development and Potential

Although the existing configuration of the BACTcontrol sensor may not be suitable for finished drinking water, recent events in other industries might justify adoption and/or testing in other applications. For example, there have been a number of recent disease outbreaks related to romaine lettuce and spinach. Although the exact source of those outbreaks has not been confirmed, expanded monitoring of bacteriological water quality might be warranted to increase public health protection and reduce risks associated with agricultural irrigation waters. Considering that irrigation waters are not always treated, the BACTcontrol technology might offer an alternative, early warning system for farmers.

About microLAN

microLAN, based in Waalwijk, the Netherlands, is a company specialized in early warning systems for water quality monitoring. microLAN has developed a range of fully automated online monitoring technologies for drinking, surface, and process water. The company’s existing products include the ALGcontrol, BACTcontrol, and TOXcontrol for monitoring algae, bacteria, and chemical toxicity, respectively.

microLAN’s online technologies rely on proven absorbance, fluorescence, and luminescence-based methods for detecting algae, bacteria, and toxicity. For bacteriological testing, the BACTcontrol relies on enzymatic activity that triggers a fluorescence response. The sensor’s reagents are target-specific so that changes in fluorescence are indicative of the presence of total coliform or E. coli, for example.

Well To Do

The Issue Facing Southern Nevada Water Authority

Southern Nevada Water Authority identified nitrates as an important issue and the organization was looking for technologies to address the growing levels of nitrate in groundwater. “Nitrate is an issue for many groundwater systems across the nation. It enters groundwater supplies primarily from pollution, including fertilizer runoff or septic system infiltration,” said Eric Wert, a project manager with SNWA Applied Water Quality Research. “The nutrient is regulated by the United States Environmental Protection Agency in drinking water supplies to minimize the health risk of methemoglobinemia, or blue baby syndrome.”

Numerous other states and even other countries are contemplating how to best address the issue to optimize water resources safely. In recent months, states including Florida and Minnesota have put forward plans to reduce the presence of nitrates in their local bodies of water. Wert said that as new treatments and technologies emerge in the water innovation field at a reduced cost, Nevada must search for sustainable solutions to address its water quality concerns.

SNWA partnered with Israeli company, WellToDo, to implement a pilot program using an innovative approach to address the groundwater nitrate issue. “The issue of nitrates in groundwater is relevant to a lot of communities and WellToDo’s approach was not one that we had seen before,” said Nate Allen of WaterStart. The pilot program in Nevada is a collaboration among WellToDo, WaterStart, the Southern Nevada Water Authority, Corona Environmental Consulting and the government of Israel.

Result of Pilot

WellToDo was chosen to address the nitrate problem at SNWA because they offer a unique solution that does not require disposal of leftover toxic waste from a treatment process, as many other potential fixes do. Early pilot testing with the SNWA showed proof-of-concept and demonstrated that the system can effectively remove nitrate and perchlorate from source water.

“Other methods collect the nitrate or contaminant in a small volume of water, so it solves the problem with the drinking water, but 10-15 percent of the water is then very, very contaminated,” says WellToDo Chief Executive Officer Hovav Gilanhe. “It’s not solving the problem. It’s just moving it somewhere else.” That somewhere else is generally a certified landfill. a costly proposition that may also involve regulatory challenges in transportation of the waste.

SNWA was impressed with more than just the ability to remove nitrates from groundwater without creating toxic waste. “The removal of perchlorate was a surprise. That had not been researched previously and presents another potential application for the WellToDo technology,” Wert said.

SNWA and WellToDo will continue to analyze, troubleshoot and optimize the process as they learn more from the pilot project. They have already made adjustments during the pilot that they believe will allow for development of the technology and refinement of the process for such projects in the future. For instance, according to Wert, they have learned through the pilot that ammonia and nitrite can be produced as byproducts of WellToDo’s reduction of the nitrates to nitrogen gas, and they are now working to minimize production of these additional products.

Additionally, during the second phase of pilot testing, WellToDo made changes to its catalyst composition after problems with the catalyst’s functionality. The second phase began in January and is ongoing. “Changing water caused us problems. My advice is just to be prepared,” Gilan said. “Every customer’s water will be different.”

About the WellToDo Technology

WellToDo utilizes its catalytic reduction process to eliminate the common pollutant nitrate from drinking and waste water. WellToDo’s product is one of the earliest-stage innovations in which WaterStart has invested so far, in large part due to its novel approach to addressing the excess nitrate problem. Prior to its Southern Nevada pilot project, the company completed two successful pilot tests in Israel. It is also conducting pilot testing with American Water in Illinois.

The partnership with WellToDo is the first time WaterStart has jointly funded a pilot with the government of Israel. Due to the Middle Eastern nation’s shared need for clean water technology in the desert and their robust water innovation program, Israel has formed a strong partnership with WaterStart through its national innovation authority.

http://welltodo.co.il/