Voluntary Programs

EPA, state regulatory agencies, AWWA, and other drinking water organizations have established voluntary programs for systems to ensure the delivery of safe water to their

customers. These programs often focus on optimizing the treatment process and identifying the limiting factors of performance. Consequently, they are excellent aids for systems considering this toolbox option. This section discusses two programs, the Partnership for Safe Water and the CCP. (The CCP is also promoted as part of the Partnership for Safe Water).

7.5.4.1 Partnership for Safe Water

The Partnership for Safe Water is a voluntary cooperative effort between EPA, AWWA, and surface water systems. The goal of the program is to “provide a new measure of safety to millions of Americans by implementing prevention programs where legislation or regulation does not exist. The preventive measures are based around optimizing treatment plant

performance, and thus increasing protection against microbial contamination in America’s drinking water supply.” (http://www.awwa.org/partner/partner1.htm).

For further information about the Partnership for Safe Water and how to join, see AWWA’s website:

http://www.awwa.org/Resources/PartnershipMain.cfm?ItemNumber=51227&navItemNumber=5 1231.

Water systems that participate in the program go through four phases:

Phase I: Commitment – operators and management indicate their willingness to complete the program through phase III.

Phase II: Data Collection and Analysis – the water system must collect one year of raw, settled, and filter effluent turbidity data and submit to AWWA for analysis.

Phase III: Self Assessment – allows the system to examine the capabilities of the existing plant’s operation and administration and identify factors that limit performance.

Phase IV: Procedures and Applications Package – systems demonstrate they addressed areas of limited performance and produce high quality water as measured by filter effluent turbidity.

Through the efforts of monitoring, data analysis, and evaluating the capabilities of unit processes, significant improvements in water quality can be achieved. In the Partnership’s 2001 Annual report, AWWA reported an increase from 20 percent to 32 percent of plants completing Phase II with finished water turbidity levels less than 0.1 NTU (based on 95th percentiles). At the beginning of Phase III, approximately 51 percent of plants reported 95th percentile turbidity less than 0.1 NTU, and after completing Phase III approximately 70 percent of plants achieved less than 0.1 NTU.

7.5.4.2 Composite Correction Program (CCP)

The CCP was developed in 1988 to optimize surface water treatment plant performance with respect to protection from microbial pathogens. The program consists of two parts, the comprehensive performance evaluation (CPE) and comprehensive technical assistance (CTA). The CPE is a thorough review and analysis of a facility’s design capabilities and associated administrative, operational, and maintenance practices as they relate to achieving optimum

LT2ESWTR Toolbox Guidance Manual 7-20 April 2010 performance from the facility. It can be conducted by the system or by a third party over a period of roughly 3 to 4 days. The CTA builds on the results of the CPE by addressing the combination of factors that limit a facility’s performance. If conducted by a third party, it should be

implemented by a third party who is in a position to pursue corrective actions in all areas, including politically sensitive, administrative, or operational limitations.

EPA published a handbook, Optimizing Water Treatment Plant Performance Using the Composite Correction Program (1998), that fully describes the goals, methods, and procedures of the CCP. To obtain a copy, call the EPA Safe Drinking Water Hotline at 1-800-426-4791.

7.6 References

American Water Works Association. 2000a. Operational Control of Coagulation and Filtration

Processes, 2nd Edition. American Water Works Association.

American Water Works Association. 2000. Water Quality and Treatment 5th Edition. McGraw Hill.

Kawamura, Susumu. 2000. Integrated Design and Operation of Water Treatment Facilities. John Wiley & Sons, Inc.

U.S. EPA. 1998. Optimizing Water Treatment Plant Performance Using the Composite

Correction Program. Office of Water and Office of Research and Development. EPA 625/6-

8.1 Introduction

Under the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), bag and cartridge filters are defined as pressure driven separation devices that remove particles larger than 1 micrometer (µm) using an engineered porous filtration media. Bag filters are typically constructed of non-rigid, fabric filtration media housed in a pressure vessel in which the direction of flow is from the inside of the bag to the outside. Cartridge filters are typically constructed as rigid or semi-rigid self supporting filter elements housed in pressure vessels in which flow is from the outside of the cartridge to the inside (40 CFR 141.2).

A pressure vessel may contain either single or multiple filters in a series or in parallel. As the water flows through a bag or cartridge filter, particles collect on the filter and the difference in pressure from the inlet to the outlet, termed “pressure drop,” increases. Once a “terminal pressure drop” is reached, the bag or cartridge filter is replaced.

Typically, bag and cartridge filters are used by small systems for protozoa or other particle removal. The pore sizes in the filter bags and cartridges designed for protozoa removal are small enough to remove protozoan cysts and oocysts but generally large enough that viruses, bacteria, and fine colloidal clays could pass through.

This chapter provides background information on the treatment performance, design, and operation of bag and cartridge filters, with emphasis on those issues that a system should

consider for integrating bag or cartridge filters into its treatment process to comply with the LT2ESWTR. This chapter is organized as follows:

8.2 LT2ESWTR Compliance Requirements - describes criteria and reporting

requirements that systems must meet to receive Cryptosporidium treatment credit. 8.3 Toolbox Selection Considerations - describes the advantages and disadvantages

of integrating a bag and cartridge filtration process for compliance with the LT2ESWTR.

8.4 Challenge Testing - describes the challenge testing that a bag or cartridge filter must pass to be awarded Cryptosporidium treatment credit for the LT2ESWTR. 8.5 Design Considerations - discusses influent water quality, size of filter system and

redundancy, layout features, filter cycling, pressure monitoring, valves and appurtenances, air entrapment, and National Science Foundation (NSF) certification.

8.6 Operational Issues - discusses pressure drop across the filter, and monitoring to assess performance and indicate possible process upsets with the bag or cartridge filter or other upstream processes.

8.2 LT2ESWTR Compliance Requirements 8.2.1 Credits

Bag and cartridge filtration processes that meet the EPA definition and demonstrate

Cryptosporidium removal through challenge testing may receive the following Cryptosporidium

removal credit for the LT2ESWTR (40 CFR 141.719(a)):

• Up to 2.0-log removal for individual bag or cartridge filters showing a minimum of 3.0- log removal in challenge testing.

• Up to 2.5-log removal for bag or cartridge filters in series showing a minimum of 3.0-log removal in challenge testing.

Challenge testing must be conducted according to the LT2ESWTR requirements outlined in section 8.4 of this chapter. A 1-log factor of safety for a single filter and 0.5-log factor of safety for multiple filters in series is applied to the allowable removal credit over that

demonstrated by challenge testing because bag and cartridge filters cannot have their integrity directly tested; hence, there are no means of verifying their removal efficiency during routine use.

Recently, some cartridge filtration devices have been developed for drinking water treatment using membrane media, which can be direct integrity tested. These membrane cartridge filters (MCFs) could be considered a membrane filtration process for the purpose of compliance with the LT2ESWTR treatment requirements for Cryptosporidium (i.e., the MCF process would be eligible for the same credit, and subject to the same requirements, as a

membrane filtration process). A direct integrity test is a physical test applied to a membrane unit to identify and isolate integrity breaches (i.e., one or more leaks that could result in

contamination of the filtrate). Manufacturers can provide information on direct integrity testing and whether it is feasible with their products. Refer to the EPA Membrane Filtration Guidance

Manual (U.S. EPA 2005) for direct integrity testing and other membrane filtration requirements. 8.2.2 Reporting Requirements

All reporting requirements for the Surface Water Treatment Rule (SWTR), Interim Enhanced Surface Water Treatment Rule (IESWTR), and Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) are still applicable; the LT2ESWTR does not modify or replace any previous rule requirements. The location of filter effluent turbidity monitoring for

compliance with the IESWTR and LT1ESWTR does not change with the installation of a bag or cartridge filter as a secondary filtration process. That is, a system would still monitor filter effluent turbidity after the primary filters for compliance with the IESWTR and LT1ESWTR.

When bag and/or cartridge filters are used to comply with treatment requirements, the LT2ESWTR requires systems to submit an initial report that demonstrates the following (40 CFR 141.721(f)):

• Process meets the definition of a bag or cartridge filter.

• Removal efficiency from challenge testing (described in section 8.4). The removal demonstrated must be 1.0-log greater than the credit awarded for a single and 0.5-log greater than the credit awarded for multiple filters in series.

This initial report must be submitted by April 1, 2012 for systems serving more than 100,000, October 1, 2012 for systems serving between 50,000 and 99,999, October 1, 2013 for systems serving between 10,000 and 49,999 and October 1, 2014 for small systems serving fewer than 10,000 people.

For routine compliance reporting, systems must verify each month that 100 percent of plant flow was treated by the bag or cartridge filter (40 CFR 141.721(f)). One possible approach states may elect to use for flow verification is to have operators certify each month that all flow was treated by the filter. States may require additional reporting at their discretion. Section 8.6 provides recommendations for filter effluent and process monitoring.