Water Quality and PFAS Treatment Pilot Study at the Potomac Water Filtration Plant

Contract No. 109582

Scope of Work

Background

WSSC Water has completed a holistic water quality and bench top treatment study and identified the following water quality concerns that require an enhanced treatment alternative or management strategy:

• Per-and Polyfluoroalkyl Substances (PFAS)

• Disinfection By-Products (DBPs)

• Total Organic Carbon (TOC)

• Manganese

• Taste and odor (Geosmin, MIB)

• Harmful Algal Blooms (HABs) and their potential toxins

• Opportunistic pathogens

• Unknown spill contaminants

• Salinity

The treatment technologies that were considered during the bench studies consisted of pre-treatment (prior to filtration) alternatives and post treatment (after filtration) alternatives. A feasibility and benefit analysis was performed to compare and identify the treatment technologies that would be further evaluated in the next step under flow through and continuous settings over a longer period of time (a minimum of 12 months), which is referred to as “pilot test” throughout this document.

Using the progressive design-build delivery method, WSSC Water now desires to pilot test various process treatment trains by selecting a qualified Team to design, construct and operate the pilot plant for the time required to obtain the target water quality listed in Table 1 in Section B of this document (“the Project”). The selected Team should have prior experience in successful collaborative project delivery designing, constructing and operating pilot plants for water treatment.

The Project will be broken into two stages: the Preliminary Stage, including design up to 70% and planning efforts for remainder of project, and the Completion Stage, including the remainder of design, construction, operations and maintenance (O&M), and handover.

The Preliminary Stage services shall include the 30% and 70% design stages, early equipment / material purchase and cost estimates leading to cost proposed and negotiations for the Completion Stage.

The Completion Stage services shall include the completion of design, construction, commissioning, operation and data collection, data compilation and reporting, maintenance, demolition and restoration, and handover.

Offerors shall submit a Technical Proposal describing their qualifications, relevant experience, and technical approach along with a Price Proposal for Preliminary Stage only. The selected Team will be awarded a Contract to perform the Preliminary Stage services.

During the Preliminary Stage, the Owner and the selected Team will negotiate the scope of work, pricing, risk allocation, schedule, and other commercial terms for the Completion Stage. Upon successful negotiation, the selected Team will be awarded a separate authorization and contract amendment to proceed with the Completion Stage and will be responsible for completing all services associated with that Stage.

The Offeror must provide advance 30 days written notice of any key personnel substitution.

Offeror must submit a written justification detailing the reason for the change and the impact on project performance. Proposed replacements must have qualifications and experience "substantially equal to or greater than" the original staff. A resume will be required. WSSC Water reserves the right to approve or disapprove the replacement of key personnel.

Descriptions of the expected services, for the Preliminary Stage, though not inclusive, are outlined below:

I. PRELIMINARY STAGE SERVICES

A. Develop design documents, up to 70% design, sufficient to construct the treatment trains to adequately pilot test the recommended alternatives. This will include identifying the proper location within the confines of the Potomac Water Filtration Plant to construct the pilot plant and design all necessary utility connections and testing ports. Design drawings and specifications shall be submitted to WSSC Water for review at various Stages of design completion; expected to be 30 and 70%. The Team will adhere to the following schedule where “days” refers to working days, for the completion of design submittals:

1. 30% Design Submittal: Submit draft version for review within 60 days from the Notice to Proceed. Allow 20 days for WSSC Water review. Final version shall be submitted within 20 days of receipt of WSSC Water review comments for WSSC approval. A workshop will be required to clarify review comments with WSSC Water stakeholders.

2. 70% Design Submittal: Submit draft version for review within 90 days of approval of the 30% Design Submittal. Allow 20 days for WSSC Water review. Final version shall be submitted within 20 days of receipt of WSSC Water review comments for

WSSC Water approval. A workshop will be required to clarify review comments with WSSC Water stakeholders.

B. The primary treatment objectives, technologies, and a brief description of the proposed pilot trains are provided in the paragraphs below. Table 2 shows the proposed pilot in integration with the current water treatment process provided at the end of this Scope of Work.

Table-1 Performance target data for each contaminant category

Target Parameter Performance Criteria

PFAS 2 ppt

DBPs 80% DBP MCL while maintaining 0.2 ppm minimum free chlorine residual while preparedness to meet higher future minimum disinfectant residual requirements

TOC below 2 mg/L

Manganese 0.015 ppm

Taste and odor (Geosmin, MIB) more reliable and greater removal than existing systems

HABs and their potential toxins

Microcystins: 0.3 ug/L

Cylindrospermopsin: 0.7 ug/L

Opportunistic pathogens No Specific Criteria

Unknown spill contaminants No Specific Criteria

Salinity 1,000 mg/L

1. Primary Treatment Objectives and Potential Treatment Approaches:

a) Enhanced Manganese (Mn) Removal –This can be difficult to meet when raw turbidity or when chlorine demand is high. WSSC Water is interested in the following technologies for manganese removal:

• Permanganate (with or without pH adjustment) – existing

• Chlorine dioxide

• Ozone

• Induced-oxide anthracite filters - existing

• Biological filters

b) PFAS Removal –Average PFAS concentration in the WSSC Water effluent is around 2 - 3 ppt for PFOA and PFOS (0 ppt by compliance calculations).

Currently, there is no PFAS treatment component within the plant. WSSC Water is interested in the following technologies for PFAS removal:

• Granular Activated Carbon (GAC) in pressure contactors (post-filtration)

• Ion Exchange (IEX) resins in pressure contactors (post filtration)

• Nanofiltration (NF) (post-filtration)

• GAC in gravity filters (retrofit existing filter beds)

• GAC/IEX in pressure contactors (post-filtration), with GAC as pre-treatment to IEX

c) Enhanced DBPs and chlorine residual – Internal targets are currently met with careful operational balance. WSSC Water is interested in the following technologies for DBPs removal:

• Enhanced coagulation – existing

• GAC

• Ozone/Biologically Active Filtration (BAF)

• Chloramines

d) Enhanced Taste and Odor (T&O) and Algal Toxins –Existing treatments within the WSSC Water plant provide limited T&O removal. WSSC Water is interested in the following technologies for T&O removal:

• Powdered Activated Carbon (PAC) - existing

• Permanganate – existing

• GAC

• Ozone/Biologically Active Filtration (BAF)

e) Opportunistic Pathogen (OP) Control and Unknown Spill Contaminants

• The pilot treatments shall remove OP

• Monitor pilot plant for chlorine demand and spills should they occur

2. Pilot Trains Selection and Evaluation Criteria:

a) Performance and/or compliance

(1) Treatment effectiveness for identified elements

(2) Possible operational problems (e.g., biofouling)

(3) Holistic system considerations (e.g., corrosion control)

b) Need for property acquisition to house footprint of treatment option

c) Constructability, complexity, and feasibility

d) Maintenance of Plant Operations (MOPO)

e) Implementation schedule

f) Life cycle cost

g) Residuals streams management

h) Operational complexity

i) Permitting requirements

Based on the items (a) through (i), a minimum of four (4) treatment trains will be selected to move to the Completion Stage.

3. Proposed Pilot Trains (refer to Table 2): During the design process, the Team is expected to apply technical experience and expertise to recommend a few different treatment trains that can generate the aforementioned water quality objectives. The pilot trains proposed below are listed as example treatment trains and are only to be used as a starting point. The Team is to collaborate with WSSC Water staff to refine the treatment combinations to be tested by bench-, pilot-, or full-scale testing;

periodic or continuous testing; the sequence and duration of testing; adsorbent selection; and the number and configuration of treatment trains. Recent bench-testing results of various technologies are provided in the Water Quality and Treatment Master Plan final report.

The following four treatment trains are proposed for inclusion in this pilot. The design-builder is encouraged to evaluate these and pursue other innovative solutions and/or combinations to meet the outlined objectives:

Note: Pilot Train 1 will use the effluent of the WSSC Water plant, which is treated with existing pretreatment chemicals, enhances coagulation, flocculation, sedimentation, filtration, and disinfection. Pilot Trains 2, 3, and 4 can be connected to the WSSC Water plant influent.

a) Pilot Train 1: Post-Filtration Enhancements – Pilot Train 1 can include (GAC) in a lead/lag configuration, IX in a lead/lag configuration, combined GAC/IX, novel absorbents, or (NF) treatment of reject stream is also required, and chloramine disinfection. WSSC Water understands that PFAS removal is achieved primarily via GAC/IX and NF polishing and upstream oxidation targets DBO precursors and Mn.

b) Pilot Train 2: Full-train Enhancement – Pilot Train 2 builds upon Train 1 by adding ozonation and biologically active carbon filters to improve removal of organic compounds that form DBPs. This train also enhances removal of taste and odor compounds, and potentially Mn. Pilot Train 2 provides PFAS and DBP polishing by the same methods as Pilot Train 1 and includes testing of chloramines for DBP control.

c) Pilot Train 3: Interim Retrofit – Pilot Train 3 incorporates existing pretreatment chemicals, enhanced coagulation, flocculation, sedimentation, the replacement of anthracite with GAC in the existing filters, and disinfection with either chlorine or chloramines. The purpose of Pilot Train 3 is to be able to take immediate action, if needed, via potential interim solution by replacing anthracite in one to all existing filters with GAC for both filtration and PFAS adsorption.

(1) Pilot: Replicates existing treatment with the ability to test pre-oxidants for

Mn control, followed by a filter column to simulate replacing anthracite in existing filters with GAC (approximately 25-inches of GAC and 12-inches of sand). The objectives of Pilot Train 3 are:

• Assess impact of limited Empty Bed Contact Time (EBCT) and regular backwashing on GAC performance.

• Assess chlorine dioxide for enhanced Mn removal in place of chlorine on anthracite filter.

WSSC Water proposes the following two tests in addition to Pilot Train 3:

(2) Full Scale Demonstration – In addition to the above pilot train, WSSC Water may consider retrofitting one or two existing filters with GAC/sand media to establish a baseline and as a proactive step prior to implementing the retrofit across 50% to 100% of all filters. Filters would be monitored for turbidity, head loss development, PFAS, TOC, manganese, and other parameters. During the Preliminary Stage, it will be decided whether the retrofit of a filter GAC/sand media will be done by WSSC Water Filtration Plant personnel or the Team. In either scenario, the Team would still be responsible for monitoring the filter performance.

(3) PAC tests for removal of PFAS is included as another potential interim solution.

d) Pilot Train 4: Intensification Retrofit – Pilot Train 4 incorporates all the existing treatment steps in addition to the installation of submerged ceramic filters in part of the existing sedimentation basins, replacement of existing filter media with GAC, and disinfection with either chlorine or chloramines. The purpose of Pilot Train 4 is to assess a permanent replacement within the existing plant footprint by adding ceramic membranes immersed in the sedimentation basins and repurposing existing anthracite/sand filters as GAC contactors. (a.k.a.

ultrafiltration) and conversion of existing filter boxes to post-filtration GAC contactors.

(1) The treatment objectives of Pilot Train 4 are:

• Assess impact of limited EBCT on GAC performance following pre-treatment with membranes

• Assess chlorine dioxide or ozone for Mn removal in place of chlorine on anthracite filter

• Assess ceramic filter impact on finished water quality and coagulation dosage

C. Services necessary to execute the Preliminary Stage may include the following:

1. Project Controls and CPM scheduling – Develop project schedules and perform schedule reviews for logic, durations, constraints, sequencing, resource loading and costing.

2. Data Accumulation and Analysis – Accumulate and review applicable data, criteria, standards, regulations, and other information pertinent to the work. Verify existing conditions that may affect or be affected by the design, even if as-builts exist.

3. Surveying – Perform surveys required for detailed design, topographical surveying, surveying for connections to existing utilities, and/or surveys to specifically locate and define existing conditions that may affect the design.

4. Hazardous Materials – Perform identification and testing of any potential hazardous materials on site, such as lead, asbestos, PCB’s, etc., which must be removed or abated prior to construction of pilot facility. Provide recommendations for removal and disposal of materials and/or remediation of the site.

5. Geotechnical Investigations – Perform geotechnical evaluation of the site to include but not limited to conducting soil borings, soils sampling, and soils testing as necessary for proper design / location of pilot facility.

6. Construction Cost Estimating – Develop detailed construction estimates at no less than the 30% and 70% design milestones based on the design drawings and specifications. Participate in price reconciliation workshops with WSSC Water’s Neutral Cost Estimator (NCE) to reconcile and validate costs.

7. Permitting – Identify permits required for the project. Prepare drawings, specifications, and applications as required for each permit. Coordinate with each permitting agency and WSSC Water staff to address issues.

8. Risk – Identify risks and opportunities for the Project and develop a Project risk register. Participate in risk workshops to develop and evaluate the risk register, update the risk register as design progresses, and agree on the appropriate allocation of risks between the parties.

9. Completion Stage Cost Estimating—Develop cost estimates and resourcing plans required for the post-construction Completion Stage activities including operations, data collection, compilation, reporting, maintenance, demolition, restoration, and handover. The cost estimate and resourcing plan should address what resources will be required for these post-construction Completion Stage activities, who intends to provide these resources, qualifications of any resources/personnel provided, time commitments broken down by week including for on-boarding.

NOTE: The Proposal for the Preliminary Stage shall include all the effort and items listed above.

II. COMPLETION STAGE, DESIGN SERVICES

NOTE: The proposal for the Completion Stage shall include all the items listed below.

Completion Stage shall not begin until 70% design is completed, a price for the Completion Stage detailed in Article 3.03 of the Agreement, and a Definitive Contract Modification has been negotiated and executed.

A. Final Design Submittal: If WSSC Water and the Team agree to a Completion Stage amendment, the Team will submit a draft final design for WSSC Water review, comment, and approval. For modifications to working plant facilities/processes contained in this submittal, precise and detailed drawings may be required. As-built drawings will be required prior to start-up and commissioning. A workshop may be required to clarify review comments with WSSC Water stakeholders.

B. The Team shall provide all materials and equipment necessary to construct the pilot plant in accordance with the approved design.

C. An amendment to the Contract requiring approval of the WSSC Water Commissioners will be required before proceeding with the Completion Stage. Once the amendment has been issued and NTP for the Completion Stage is issued, the Team may proceed with constructing the pilot plant. A preconstruction conference with Project stakeholders will be required before commencing construction, and the Team will need to coordinate all construction Work and interruptions to treatment plant operations with WSSC Water and any other Project stakeholders. It is anticipated that periodic progress meetings will be held with the Team, WSSC Water and any other Project stakeholders until the construction Work is completed.

III. COMPLETION STAGE, CONSTRUCTION AND COMMISSIONING

A. Design-Builder shall perform and furnish the construction of the pilot in accordance with the Final Design documents.

B. Design-Builder shall keep Owner advised as to the progress of the Construction.

IV. COMPLETION STAGE, OPERATION AND TESTING

A. The Team shall provide the manpower and incidental materials necessary to operate the pilot plant in accordance with the design parameters as stated in the contract documents.

Additionally, the Team shall be responsible for all laboratory testing of water samples necessary to determine treatment train performance.

1. The testing and data collection shall include any testing and performance data that may be required to satisfy the regulators who will be approving the new technology.

B. It is anticipated that the pilot plant will need to be operated for 12 to 18 months to collect the necessary performance data. WSSC Water may provide limited manpower to assist with operating the plant on an as-available basis.

1. It is expected that the design builder shall conduct all testing operations. The

WSSC project manager may determine what services provided by the WSSC Consolidated Laboratory be considered as a best-value alternative in lieu of contracted laboratory services.

2. WSSC project manager may elect for the WSSC Consolidated Laboratory team to run parallel tests at project manager determined intervals.

V. COMPLETION STAGE, MAINTENANCE OF THE PILOT TRAINS

A. The Team shall maintain all process trains and all electrical, mechanical, structural, plumbing appurtenances that are part of the process trains for the duration of operation of the pilot.

B. During the development of the Completion Stage Scope, maximum allowable down times and response requirements will be established.

C. The estimated cost for this Work effort is to be included in the cost proposal for the Completion Stage.

VI. COMPLETION STAGE, DEMOLITION AND RESTORATION

A. Once the pilot operation is complete, the Team shall demolish or remove all elements of the process trains and restore the site to the original condition including electrical connections, mechanical equipment, and the site.

B. The demolition and restoration plan shall be approved by, and conducted in coordination, with WSSC plant and engineering staff, to maintain plant operations.

VII. COMPLETION STAGE, DATA COMPILATION AND REPORTING

A. The Team shall compile all the data collected while operating the pilot plant, analyze this data to determine how each treatment train performed, and prepare a final report that WSSC Water will utilize to select treatment technologies during the next phase of the project.

B. The final report shall include (at a minimum) the following three sections:

1. Water Quality Test Data

a. As part of the pilot plant operations phase, compile appropriate data collected during operation. Discuss the attributes of each treatment train.

b. Provide tabulated and narrative comparisons discussing the effectiveness of treatment for each water quality parameter.

2. Budgetary Costs

a. Provide budgetary costs should WSSC repeat construction and maintenance of this facility. Include construction, plus annual operation and maintenance, per treatment train.

3. Report of similar facilities in the US.

a. Include all or at least 20 recently (since 2015) started or completed projects that provide treatment using any of the methods tested in this pilot, with a scale of 100-300 MGD in the United States.

b. For each project provide cost, treatment volume, type of treatment, and projected annual maintenance costs.

c. Provide treatment and building footprints (in square feet).

d. Provide any laboratory data on treatment efficiency or effectiveness.

C. The estimated cost for this Work effort is to be included in the cost proposal for the Completion Stage.

D. The Team should anticipate two review workshops prior to completing the final report.

E. The final report will need to be reviewed by WSSC Water stakeholders prior to approval.

Table 1. Proposed Pilot Treatment Trains

DisinfectionPost-filtration PolishFiltrationSedimentationCoagulation/ Flocculation (2)

PretreatmentPilot Train

Chlorine---Pre-filter chlorine(1) Anthracite 25” (1) over Sand 12”

ConventionalSulfuric acid PACl Ferric sulfate

Permanganate (1,2)

PAC (2,3)

Existing Treatment

New process enhancements are to be tested as additional and/or in substitution to existing processes

Chloramines (2)GAC (2,3) or IEX (2,3) or GAC/IEX (2,3) or Novel Adsorbents (3) or

NF (2,3,4)

Train 1 Post-filtration Enhancement

Chloramines (2)GAC (2,3) or IEX (2,3) or GAC/IEX (2,3) or Novel Adsorbents (3) or

NF (2,3,4)

Biological filtration (1,2)

Ozone (1,2)Ozone (1,2)Train 2 Full-train Enhancement

Chloramines (2)GAC 25” (2,3) over Sand 12”

Chlorine Dioxide (1,2)Train 3 Interim Retrofit

Chloramines (2)GAC 37” (2,3)Ceramic UFReduced settling time Ozone (1,2)

Chlorine Dioxide (1,2) Ozone (1,2)

Train 4 Intensification Retrofit

Note 1 – Targeting Manganese Note 2 – Targeting DBPs, Taste and Odor, Algal Toxins, and Chlorine residual management Note 3 – Target PFAS Note 4 – NF highest potential recovery; Includes pilot of NF reject treatment

2. WSSC project manager may elect for the WSSC Consolidated Laboratory team to run parallel tests at project manager determined intervals.