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Surface Water Treatment
What is Optimization?
Current Optimization Goals
What's New?
Free Training Opportunities
Learn More About...
Forms, Tools & Resources


Background & Introduction
The information on this page is intended for operators and owners of water systems that treat a surface water source. Water systems that treat surface water sources have to deal with complicated regulations for Oregon Drinking Water Services (DWS), Department of Environmental Quality, Water Resources Department, and various other state and local entities. In addition to these regulatory requirements, systems have to adhere to National Sanitation Foundation treatment and Oregon's construction standards (PDF), water rights requirements, constantly changing raw water quality including periodic algae blooms and high turbidity (PDF) events, and costly management of various assets. Information below is being presented to provide operators the information and tools needed to optimize water treatment processes to maximize public health protection without costly capital improvements. Although primarily focused on treatment optimization, this page also provides technical, managerial, and financial resources (e.g., Oregon's Drinking Water State Revolving Fund) needed to build water system capacity. Particularly useful is the U.S. Environmental Protection Agency's Small Public Water Systems and Capacity Development Web site and the free technical assistance offered through the DWS Circuit Rider Program. If you have specific topics that you believe should be included on this page, comments about the content of this material, or discover links that do not work, please contact us.

Figure 1. Multiple Barriers



Water Treatment Optimization
Water treatment plant optimization is the process of improving the performance of particle removal beyond regulatory requirements without making major capital expenditures. As outbreaks (e.g. in 1993 in Milwaukie, WI) have made clear it clear that just meeting current regulatory water quality standards might not be enough to protect against contaminants. For these reasons, surface water treatment plants are encouraged to optimize their treatment processes and adopt more stringent water quality goals (PDF) as a component of the multiple barrier approach (PDF) to protect against these contaminants and prevent waterborne disease outbreaks. For more information and a table of recommended optimization goals, read about Area Wide Optimization below.

Figure 2. Multiple Barrier Goals



Area Wide Optimization (AWOP)
In order to assist treatment plant operators and promote optimization concepts, a network of partners including the U.S. Environmental Protection Agency (EPA), state drinking water programs, Process Applications, Inc., and the Association of State Drinking Water Program Administrators (ASDWA) have teamed up to implement a national Area Wide Optimization Program (AWOP). AWOP is a non-regulatory approach to identify and address performance limiting factors at surface water treatment plants.

DWS has joined with neighboring states and EPA Region 10 to participate in AWOP. In Oregon, AWOP is focused on optimizing particle removal at existing surface water treatment plants in order to maximize public health protection by minimizing exposure to pathogens such as Giardia (PDF) and Cryptosporidium (PDF).

Oregon's AWOP is currently focusing on implementing optimization activities for conventional and direct filtration treatment plants and establishing goals for turbidity (PDF) removal. Conventional treatment includes a clarification process prior to filtration. In direct filtration, coagulated water is directed straight to the filters without the intermediate clarification process. The diagrams below illustrate the differences between conventional and direct filtration:


Figure 3. Conventional Filtration Schematic




Figure 4. Direct Filtration Schematic




Table 1. Oregon Area Wide Optimization (AWOP) and Water Treatment
Plant Goals are listed below (refer to water treatment and system type)

SEDIMENTATION
(for Conventional Filtration)
Turbidity Criteria
Settled Water = 2.0 NTU, 95% of the time. If average annual raw water turbidity is > 10 NTU.
= 1.0 NTU, 95% of the time. If average annual raw water turbidity is = 10 NTU.
FILTRATON
(for Conventional and Direct Systems)
Turbidity Criteria
IFE and CFE Filtered Water
  • Turbidity = 0.10 NTU, 95% of the time.
  • Max. turbidity = 0.30 NTU.
Based on maximum values recorded during 4-hour increments (excluding the 15-minute period following backwash).
IFE filtered water after backwash
  • Turbidity returns to = 0.10 NTU within 15 minutes after backwash.
  • Max. spike = 0.30 NTU.
  • Turbidity at return to service = 0.10 NTU.
Goals apply to both systems with and without filter-to-waste capability. Goals also apply to the backwash recovery period starting immediately after backwash.
IFE = Individual Filter Effluent; CFE = Combined Filter Effluent


For more information, click links below:

Coagulation
Coagulation (PDF) is a process where chemicals are added to water in order to improve subsequent treatment processes. Chemicals may include pH adjusters and various polymers. Coagulants (such as alum) neutralize positive or negative charges on small particles allowing them to stick together and form larger particles that are more easily removed by sedimentation (i.e., settling) or filtration. Chemicals and components used to treat water must be certified for potable use under NSF/ANSI Standard 60 (chemicals) or 61 (components). A variety of devices, such as baffles, static mixers (shown right), turbines (shown extreme right), impellers, and in-line sprays can be used to mix the water and distribute the chemicals evenly. This process is usually called rapid mix.

Click the links below to learn how to:

Flocculation
Flocculation (PDF) typically follows coagulation and rapid mixing, and is the process where chemically treated water is sent into one or more basins (or stages) where suspended particles can collide and agglomerate (i.e., stick together) and form larger particles called "floc." Gentle agitation of the water by paddle mixers (shown right) or impeller type blades and appropriate detention times (i.e., the length of time water remains in the basin) help facilitate this process. It is important that conventional filtration systems with a treatment plant sedimentation process strive for a larger, heavier floc that is easier to settle out. In some types of treatment systems, such as direct filtration without a sedimentation/clarification process, a smaller "pin" floc is more desirable.

Click the links below to learn how to:

Sedimentation/Clarification
Following flocculation (PDF), a sedimentation or clarification (PDF) step can be used to remove larger particles. During sedimentation, the velocity of the water is decreased so that the suspended material (including flocculated particles) can settle out by gravity. Once settled, the particles combine to form a sludge that is later removed from the bottom of the basin. Settling plates (shown right) or incline square or rectangular tubes (shown below right) are sometimes used to accelerate this process. A wide variety of other clarification processes can then be used to remove floc as well. Sedimentation used to remove solids prior to chemical addition (called pre-sedimentation) may also be employed to aid treatment.

Click here (PDF) to learn more about the following topics:
  • Dissolved Air Flotation (DAF),
  • Contact adsorption clarifiers,
  • Solids contact clarifiers, and
  • Optimize sedimentation.

Filtration
With most of the larger particles typically removed after sedimentation/clarification (PDF), clarified water passes through a filtration process. In rapid sand filtration, at a rate of between 2-10 gpm per square foot, the water is filtered through an approximate 36-inch depth of graded sand. Filters are periodically cleaned by backwashing (reversing the flow of water through the filter). Anthracite coal or activated carbon may also be included in addition to sand to improve the filtration process, especially for the removal of organic contaminants and taste and odor problems. Pressure filters are similar to rapid sand filters, except that the water enters the filter under pressure. Slow sand filtration occurs at a slower rate of 0.5-1.0 gpm per square foot and is aided by a biological layer called schmutzdecke.

Other types of filtration processes can be used without coagulation, and include membrane and cartridge filtration, as well as diatomaceous earth.

Click the links below to learn how to:
Click the links below to learn more about:

Disinfection
Disinfection (PDF) involves inactivating pathogens from filtered water with the use of chlorine, chloramines, or other oxidizing agent, and can include ultraviolet light.

Chlorine disinfection (PDF) is achieved through delivering a chlorine dose with adequate contact time (CT) (shown right). The parameter CT is defined as the free Chlorine residual as measured at or before the first user (in mg/l) multiplied by the contact Time (in minutes) between the point of chlorine addition and the point at which chlorine is measured.  [CT = Chlorine concentration X contact Time]

Chloramination (PDF) involves adding ammonia to chlorinated water. Although not as effective a disinfectant, chloramination allows the chlorine residual to be carried further in large distribution systems, and has the added benefit of reducing the formation of disinfection byproducts (a product of the reaction of chlorine with organic matter).

Ozone (PDF) is a powerful oxidizing and disinfection agent, and is formed by passing dry air through a system of high voltage.

With ultraviolet light (PDF) (shown below right), there is no residual concentration to measure in the water. Other parameters such as UVT, intensity, dose, and flow are used to verify adequate disinfection for systems with ultraviolet light.

Click the links below to learn more about:


Forms & Tools
The following links go to forms and tools most commonly used by surface water treatment systems. These include a summary of turbidity and coliform sampling requirements, the monthly form to report turbidities, and CTs, public notice templates, as well as EPA Quick Reference Guides for various surface water treatment rules.

Figure 6. Turbidity and Backwash Trending Data



Technical, Managerial & Financial Resources
The following organizations (see Table 2 below) offer technical assistance and additional information related to surface water treatment. Staff or members of these corporations or associations have experience with surface water treatment plant operations and are able to serve as a resource for owners and operators that wish to maximize protection of public health by optimizing plant performance. Resources include grants, loans, technical assistance, and other information. Following Table 2 below, full descriptions of technical and managerial and financial resources are provided.


Table 2. Surface Water Treatment (SWT) Resources

Resources Assistance Type Purpose
Grants Loans T.A.1 Planning New
Systems2
Rehab3 O&M4 M&A5
American Water Works Association No Yes No Yes Yes Yes No No
American Water Works Association - Partnership for Safe Water No No Yes Yes No No No No
Bonneville Power Administration - Energy Smart Industrial Program Yes No Yes No Yes Yes Yes No
Drinking Water Services Drinking Water State Revolving Fund (DWSRF) No No Yes No No No Yes Yes
DWS DWSRF - Circuit Riders No No Yes No No No Yes No
Energy Trust of Oregon (for PGE, Pacific Power, NW Natural, or Cascade Natural Gas customers) No No No Yes No No No Yes
Environmental Finance Center Network - Boise State University Yes Yes No No Yes Yes Yes Yes
National Environmental Services Center No Yes Yes Yes No No Yes Yes
Oregon Association of Water Utilities Yes No Yes Yes Yes No No No
Oregon Department of Environmental Quality - Drinking Water Protection No No Yes Yes Yes Yes Yes Yes
Oregon Infrastructure Finance Authority No No Yes Yes No No No Yes
Oregon Water/Wastewater Agency Emergency Response Network (ORWARN) No No Yes Yes Yes Yes No No
Public Utility Commission of Oregon (PUC): Water Division Yes Yes Yes Yes Yes Yes Yes Yes
Rural Community Assistance Partnership (RCAP) Yes Yes Yes Yes Yes Yes Yes Yes
U.S. Department of Agriculture - Rural Development Yes Yes Yes Yes Yes Yes Yes Yes
U.S. Economic Development Administration No No Yes No No No Yes Yes
U.S. EPA - Check Up Program for Small Systems (CUPSS) No No Yes No No No Yes Yes
U.S. EPA - Office of Ground Water & Drinking Water No No Yes Yes No No No No
U.S. EPA - Technical Assistance Center Network (TAC) No No Yes Yes Yes Yes Yes Yes
U.S. EPA - Tribal Resource Directory for Drinking Water and Wastewater Treatment No No Yes Yes No No No Yes
U.S. EPA - Water Systems and Capacity Development Yes Yes No Yes Yes Yes Yes No
Footnote:
1. Technical Assistance and Training
2. Design and Construction for New Systems
3. Design and Construction for Rehabilitation
4. Operations and Maintenance
5. Management and Administration



Technical Resources: The following resources provide assistance related to planning, operations, and maintenance for surface water systems.
  • Bonneville Power Administration (BPA) - Energy Smart Industrial (ESI) Program: Works with BPA utility customers to deliver cost-effective energy efficiency in all industrial sectors. ESI program staff are experts in industrial sector energy efficiency. They provide technical expertise and resources that may not be available at the utility level to help utilities achieve energy efficiency goals. Program delivery is customized for each utility to assure that utility/end-user relationships are maintained, existing utility industrial programs are not impacted, and projects are completed to the satisfaction of both utilities and end-users.
  • DWS Circuit Riders: Through the DWS Drinking Water State Revolving Fund (DWSRF), contracts have been established with drinking water circuit riders to provide on-site technical services for community water systems serving populations under 10,000. For these community water systems, circuit rider services are free and are designed to address short-term operational problems; services are limited to 10 hours per issue (unless otherwise approved by DWS management staff). Some examples of short-term operational problems for which circuit rider assistance is available include conducting tracer studies, assessing filter performance, conducting jar tests, and flocculation and sedimentation process evaluations.
  • Energy Trust of Oregon: The Energy Trust of Oregon can help water treatment systems who are served by Portland General Electric, Pacific Power, NW Natural, or Cascade Natural Gas with technical assistance, finding a contractor, installation, renewable energy solutions, cash incentives for more efficient motors, and more. Call toll-free at 866-368-7878.
  • Environmental Finance Center Network - Boise State University (EFC-10): Boise State University is the site of the Environmental Finance Center (EFC) for U.S. EPA Region 10 (one of nine universities serving the regions around the country). The EFC-10 provides help to those facing the "how to pay" challenges of environmental protection. EFC-10 is committed to helping the regulated community build and improve the technical, managerial, and financial capabilities needed to comply with federal and state environmental protection laws.
  • The National Environmental Service Center (NESC)'s National Drinking Water Clearinghouse (NDWC) is a public service organization dedicated to helping small communities by collecting, developing, and providing information and free and low-cost publications, products, databases, referrals, and more. The NEC publishes technical briefs related to water treatment and operations; examples include technical briefs on package plants, membrane filtration, and calibrating liquid feed pumps.
  • Oregon Association of Water Utilities (OAWU): A non-profit independent organization that provides service and support to water and wastewater treatment facilities statewide. Services offered include training, technical support with treatment operations, and operator certification.
  • Oregon Department of Environmental Quality (DEQ)'s Drinking Water Protection Program: Oregon promotes drinking water protection through a partnership between DEQ and DWS. The DEQ site has information on how to develop drinking water protection strategies, potential contaminant sources, fact sheets on drinking water protection, an overview of drinking water protection rules in Oregon, example drinking water protection plans, and example drinking water protection ordinances.
  • Oregon Water/Wastewater Agency Emergency Response Network (ORWARN): ORWARN is comprised of member utilities providing voluntary assistance to each other during an emergency incident.
  • Public Utility Commission of Oregon (PUC) Water Division: The PUC regulates customer rates and services of certain water companies, but does not regulate people's utility districts, cooperatives, or municipally-owned utilities except in matters of safety. The PUC ensures consumers receive utility service at fair and reasonable rates, while allowing regulated companies the opportunity to earn an adequate return on their investment.
  • Rural Community Assistance Partnership (RCAP) and the Rural Community Assistance Corporation (RCAC): RCAC is the Western RCAP operating in states of AK, AZ, CA, CO, HI, ID, MT, NV, NM, OR UT, WA, and WY and provides technical, managerial, and financial assistance to water, wastewater, and solid waste systems. Specifically, the RCAC assists water treatment facilities with design and engineering of unit process improvements, as well as performing financial analyses and rate studies to support such improvements.
  • Technical Assistance Center Network (TAC): TAC assists small public water systems, including systems that serve tribes, to acquire and maintain the technical, managerial, and financial capacity needed to consistently provide safe drinking water.
  • Tribal Resource Directory for Drinking Water and Wastewater Treatment: This searchable directory is a comprehensive catalog of over thirty federal and other programs that offer funding and technical support for tribal drinking water and wastewater systems.
  • The U.S. Department of Agriculture Rural Development's Water and Environmental Programs (WEP): WEP provides loans, grants, and loan guarantees for drinking water, sanitary sewer, solid waste, and storm drainage facilities in rural areas and cities and towns with populations of 10,000 or less. Public bodies, non-profit organizations, and recognized Indian tribes all may quality for financial and technical assistance through this organization.

Managerial and Financial Resources: The following resources offer funding and resources for managers and administrators of surface water systems.
  • Oregon's Drinking Water State Revolving Fund (DWSRF): DWSRF provides low-cost financing for construction and/or improvements of public and private water systems.
  • Bonneville Power Administration's Energy Smart Industrial (ESI) Program: The ESI Program works with BPA utility customers to deliver cost-effective energy efficiency in all industrial sectors. ESI Program staff are experts in industrial sector energy efficiency. They provide technical expertise and resources that may not be available at the utility level to help utilities achieve energy efficiency goals. Program delivery is customized for each utility to assure that utility/end-user relationships are maintained, existing utility industrial programs are not impacted, and projects are completed to the satisfaction of both utilities and end-users.
  • Energy Trust of Oregon: Energy Trust of Oregon can help water treatment systems that are served by Portland General Electric, Pacific Power, NW Natural, or Cascade Natural Gas with technical assistance, finding a contractor, installation, renewable energy solutions, cash incentives for more efficient motors, and more. Call toll-free at 866-368-7878.
  • Environmental Finance Center Network - Boise State University (EFC-10): Boise State University is the site of the Environmental Finance Center (EFC) for U.S. EPA Region 10 (one of nine universities serving the regions around the country). The EFC-10 provides help to those facing the "how to pay" challenges of environmental protection. EFC-10 is committed to helping the regulated community build and improve the technical, managerial, and financial capabilities needed to comply with federal and state environmental protection laws.
  • Oregon Infrastructure Finance Authority (IFA): IFA helps communities develop infrastructure and addresses their utility and economic development needs through the following programs:
    • Community Development Block Grants: For non-entitlement cities and counties for a variety of community facilities, public works projects, housing rehabilitation, and services to micro-enterprises and other businesses where the proposed project will primarily benefit low- and moderate-income people.
    • Safe Drinking Water Revolving Loan Fund and Drinking Water Source Protection Fund: These loan programs fund drinking water system improvements needed to maintain compliance with the Federal Safe Drinking Water Act. The Safe Drinking Water Revolving Loan Fund (SDWRLF) is designed for collection, treatment, distribution, and related infrastructure projects and the Drinking Water Source Protection Fund (DWSPF) is designed for the protection of drinking water sources.
    • Special Public Works Funds: Funding opportunities for construction and/or improvement of infrastructure needed to support industrial, manufacturing, and certain types of commercial development.
    • Water/Wastewater Financing Program: Available for construction and/or improvement of water and wastewater systems to meet state and federal standards.
  • Rural Community Assistance Partnership (RCAP) and the Rural Community Assistance Corporation (RCAC): RCAC is the Western RCAP operating in states of AK, AZ, CA, CO, HI, ID, MT, NV, NM, OR UT, WA, and WY and provides technical, managerial, and financial assistance to water, wastewater, and solid waste systems. RCAC assists water treatment facilities with design and engineering of unit process improvements as well as performing financial analyses and rate studies to support such improvements.
  • U.S. Department of Agriculture Rural Development's Water and Environmental Programs (WEP): WEP provides loans, grants, and loan guarantees for drinking water, sanitary sewer, solid waste, and storm drainage facilities in rural areas and cities and towns with populations of 10,000 or less. Public bodies, non-profit organizations, and recognized Indian tribes all may quality for financial and technical assistance through this organization.
  • U.S. Economic Development Administration and Economic Adjustment Assistance Program: These programs provide grants for public works and economic development.
  • U.S. EPA Check Up Program for Small Systems (CUPSS): CUPSS is a free, easy-to-use asset management tool for small drinking water and wastewater utilities. CUPSS provides a simple, comprehensive approach based on EPA's highly successful Simple Tools for Effective Performance (STEP) Guide Series (PDF). Use CUPSS to help you develop:
    • Record of your assets
    • Schedule of required tasks
    • Understanding of your financial situation
    • Tailored asset management plan
  • U.S. EPA's Small Systems and Capacity Development: This resource is designed to help small system owners and operators, state and tribal agencies, technical assistance providers, and consumers learn more about helping small water systems provide safe drinking water and protect public health. Every state has a capacity development program to help small systems improve their finances, management, infrastructure, and operations.
  • Technical Assistance Center Network (TAC): TAC consists of eight universities that help small public water systems acquire and maintain the technical, managerial, and financial capacity needed to consistently provide safe drinking water. TAC addresses the needs of small public water systems, including systems that serve Indian tribes, by applying university resources in the following areas:

Algae Resources
Please visit the Algae Resources page for information on algae and drinking water.

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