Figures Figure 1. Schematic Diagram of the Challenge 3 Figure 2. Process Block Diagram of the FGD Blowdown Treatment System 5

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1 IWC Case Study: Cost-minimization Approach to the Design, Procurement, Installation and Commissioning of a FGD Wastewater Treatment System at a Power Station Antonio O. Lau, Ph.D., Infilco Degremont, Inc. Richard A. Ubaldi, Infilco Degremont, Inc. Michael G. McDonough, Dominion Resources Services, Inc. Edward V. Bowes, formerly with Dominion Wayne G. Spitzner, formerly with Dominion Keywords: Flue Gas Desulfurization, Wastewater, Heavy Metals, Open Book Table of Contents Abstract 2 Background 2 Introduction to the Challenge 2 The Technical Challenge and its Solution 3 The Open Book Concept for Project Implementation 6 The Goal 6 Scope and Responsibility 7 Payment Basis 9 Major Commercial Terms 9 Benefits of a DRS-IDI Open Book Alliance 10 Project Execution 12 Summary 12 References 12 Acknowledgements 12 Figures Figure 1. Schematic Diagram of the Challenge 3 Figure 2. Process Block Diagram of the FGD Blowdown Treatment System 5 Tables Table 1. Removal of Total Suspended Solids (TSS) and Heavy Metals from the FGD Blowdown Stream 4 Table 2. Benefits of a DRS-IDI Open Book Alliance 10 1

2 Abstract An innovative approach was utilized to design, procure, install and commission a FGD wastewater treatment system at a power generating station in Virginia. Dominion Resources Services, Inc. (DRS) and Infilco Degremont, Inc. (IDI) partnered to develop and optionally install a cost-effective flue-gas desulfurization (FGD) wastewater treatment system using a phased, Open Book approach. One of the critical steps in this approach is to define the wastewater treatment process interactively between the Owner, DRS, and the scrubber and wastewater treatment Equipment Suppliers. This step proved to be successful in minimizing the overall project cost because it recognized the inter-dependent design aspects of two important systems previously evaluated independently, while eliminating those expenditures associated with uncertainties (i.e., contingencies) normally built into a process design in typical competitive bids. This highly successful project was commissioned in 2009, costs were kept below the target value, and the facility met all the performance guarantees. A detailed discussion on the implementation of this Open Book concept is provided in this paper. Background Air emissions from coal-fired power plants require the installation of various types of air pollution control system technologies. One such technology is the use of wet scrubbers for the removal of sulfur dioxide (SO 2 ) from stack emissions. The wet scrubbing of flue gases with lime or limestone slurries is a proven and commercially established process to decrease SO 2 emissions. However, inherent with this system is the blowdown of a slurry stream that contains elevated concentrations of suspended and dissolved solids, chlorides, sulfates, heavy metals (chromium, mercury, selenium, etc.), and nitrates. FGD systems available in the marketplace have different combinations of characteristics (such as coal type, scrubber type, additive use, operational strategies, etc.) that result in extremely varied wastewater characteristics. This paper describes the unique implementation of a physical/chemical treatment process for the removal of total suspended solids (TSS) and heavy metals from a FGD blowdown stream. Introduction to the Challenge The DRS project engineering team developed the conceptual process values and system design, and then commissioned detailed engineering of the FGD system and Balance of Project designs to an Architectural/Engineering consulting engineering firm. They also decided that economically the gypsum produced by the FGD system would not be landfilled, but rather sent to a wall board manufacturer who provided stringent gypsum quality criteria. The final component of the FGD system required a downstream wastewater treatment (WWT) system to handle the variable characteristics of the blowdown stream. Thus, an iterative design approach had to be undertaken to generate the most cost-effective wastewater treatment system that was 2

3 flexible enough to handle the expected blowdown variations while equally matched to the most cost-effective scrubber system. This integrated System is extremely important because a malfunctioning WWT System would compromise the gypsum quality, requiring it to be sent to a landfill, or worse, cause the issuance of violation notices because of effluent excursions. Figure 1. Schematic Diagram of the Challenge Gas Scrubber Gypsum Blowdown WWT System Because the cost of the initial scrubber system is so much higher than the downstream WWT System, scrubber decisions often come first, and the WWT System must be designed to match the scrubber blowdown values required to maintain gypsum quality. A typical project execution method would then commission a consulting engineering firm to broadly layout the WWT System parameters and have separate supplies bid an independent detailed design. However, DRS, who has a competent engineering staff of their own, decided to explore the advantages of an Open Book agreement directly with a WWT supplier who had expertise in treating complex FGD wastewaters and could assist in optimizing the integration of the various processes directly with DRS. Under this approach, the commissioned engineering firm was used as the overall project advisor. DRS also had options of their own relating to the siting of the WWT system within the plant boundaries which affected the design, layout and ultimate cost. These options also benefitted from the Open Book collaboration. The Technical Challenge and its Solution IDI has extensive experience in designing WWT systems for FGD wastewaters. The influent design parameters were the following: Flow Rate: 300 gpm (150 gpm per scrubber) Total Suspended Solids (TSS): 20,000 mg/l Total Dissolved Solids (TDS): 20,000 60,000 mg/l Chlorides: 30,000 mg/l 3

4 The requirements of the WWT system were as follows: Meet or exceed 20 heavy metal effluent requirements. Provide 99% operational reliability. Comply with the limited space availability. WWT system to be completely indoors. Design a future biological treatment system to meet expected requirements for selenium and nutrient control. The WWT system proposed by IDI met all these requirements and is shown below in Table 1 and Figure 2. Table 1. Removal of Total Suspended Solids (TSS) and Heavy Metals from the FGD Blowdown Stream Parameter Removal Efficiency (%) TSS 99.9 Ag 90 Al 99.5 As 96.7 Cd 95 Cu 95 Cr 70 Fe 99.7 Hg 90 Ni 75 Pb 90 Zn 98 4

5 Figure 2. Process Block Diagram of the FGD Blowdown Treatment System FGD Wastewater 300 GPM (Max) ph = 6.0 Equalization Tank Lime Desaturation Tank ph = Sludge Recycle Organo-Sulfide Coagulant Metals Precipitation Tanks Flocculant Sludge Waste Clarifiers/Thickeners (DensaDeg ) HCI Effluent Tank Sludge Dewatering System Ash Storage Area 5

6 The overall treatment process consisted of the following components: 1. Wastewater Equalization Tank. 2. Desaturation Tank for ph elevation and gypsum desaturation using lime, (Ca(OH) 2 ), to raise the ph to the required level for optimum treatment. 3. External Sludge Recirculation from the DensaDeg Clarifiers/Thickeners to the Desaturation Tank to aid in gypsum desaturation. 4. Heavy Metal Precipitation Tanks (2 tanks) using an organo-sulfide solution. 5. Dosing of a Coagulant, such as ferric chloride. 6. Dosing of a Flocculant aid (e.g., polymer) to the Reactor Tank of the DensaDeg units. 7. Flocculation, Sedimentation, Thickening and Final Clarification in the DensaDeg Clarifiers/Thickeners (2 units). 8. ph adjustment at the outlet of the DensaDeg units to a ph range of Excess sludge removal from the DensaDeg units. 10. Effluent Tank. 11. Sludge dewatering system (Sludge Holding Tank and 2 recessed chamber filter presses). The Open Book Concept for Project Implementation The Goal The goal of the Open Book approach was to establish an exclusive contractual relationship to align the resources of DRS and IDI to work together toward a common goal of achieving a superior, value-added FGD blowdown WWT System design. This approach would also utilize the expertise from all three parties (DRS, IDI and the Engineer) to develop an optimally designed, environmentally compliant WWT System in accordance with all current federal, state and local codes, laws and regulations. The goals of the parties further included defining in greater specificity the following items: Wastewater influent and effluent characteristics, physical-chemical and biological treatment considerations, operating parameters and transients and both current and projected regulatory thresholds. 6

7 Required WWT System components and redundancy. Required chemical and polymer selection and consumption. Footprint location on a crowded power plant site. WWT System capital cost. Development of the construction bid package based on final engineering drawings. Expedited implementation schedule. Construction oversight and/or management. Start-up, testing and commissioning. Operator training and system turnover. Operating considerations and refinements. Cost of initial investment (including start-up spare parts and consumables). Sludge production, dewatering capabilities and disposal. Individual equipment warranties and overall system performance parameters. Scope and Responsibility The itemized WWT System scope and responsibility of the parties were outlined in five phases. Phase I Joint Development This first phase consisted on the following activities by the IDI Team at no cost to DRS. Participated and provided technical support to include, but not be limited to, participation in the design and scheduling coordination meetings, meetings with plant operators, and touring appropriate facilities as required. Provided preliminary layout, flow and P&ID drawings, boundary interfaces and related documentation and data for the WWT System, including better definition of the influent and effluent parameters and their possible variations. 7

8 Progressively developed a scope of supply and services and corresponding WWT System target pricing, cost and consumption of chemicals and polymers and with options and/or alternatives. Assisted in providing technical support and commercial discussions as necessary to better discuss and promote the technology of the WWT System. Provided technical support to DRS in its permit applications and any public hearings that were required. The DRS Team provided its parallel support and any third party costs required to achieve the above goals. At the conclusion of Phase I, a not-to-exceed target price was developed and DRS made their decision to proceed with a full contract covering the balance of the Phases. Had DRS decided not to go further than Phase I, IDI would have been paid a not-to-exceed documented cost previously agreed upon by both organizations. Phase II Detailed Engineering and Design Continuing from the support items in Phase I, IDI provided the following: Coordinated the development of the Project s Critical Path Milestones (CPM) with DRS as it related to the System supply. Completed all process engineering and design and submitted to DRS for review and approval of all drawings and documentation. Refined bidder s list and solicited competitive bids for all equipment and any required third party services. Completed all bid evaluations, shared evaluation results and recommendations with DRS. Processed the awards to selected equipment bidders. Completed all WWT System descriptions. Phase III Equipment Procurement, Fabrication and Delivery Provided equipment costs with an explicit mark-up. Jointly prepared a construction bid package for DRS use. Phase IV Start-up, Testing and Equipment Commissioning Provided support for the start-up, testing and commissioning of the WWT system based on agreed upon service rates for IDI personnel conducting field work. 8

9 Phase V - Warranty Period Provided a 2 year warranty for all supplied equipment. Payment Basis As noted above, the DRS-IDI Open Book alliance used an incentivized payment schedule wherein both parties benefited from the long-term working relationship. The following general provisions were used: Payments to IDI were linked to the five phases of the Project. IDI offered to pay its own internal and approved third-party costs during Phase I. Payment for the balance of the phases was linked to defined, mutually agreed set of milestones with the expectation that they included as a minimum, coverage for detailed engineering, release for fabrication, equipment delivery and final commissioning. IDI s detailed internal and third-party engineering, procurement and project coordination costs, including overhead and margin, were a lump-sum, not-to-exceed cost guarantee plus a determined and explicit percentage management and profit fee. Agreed overage and/or approved change notices were billed at an agreed upon rate. IDI s proprietary equipment and third-party equipment were furnished as a lump sum not-to-exceed cost guarantee plus a management fee. IDI provided site field service cost for in-state start-up, testing, commissioning and any follow-up non-warranty service at an agreed-upon rate. An incentive program was also implemented to provide both parties with opportunities to reduce costs and prevent overruns. Major Commercial Terms The following major commercial terms were included in the Open Book agreement: IDI guaranteed meeting mutually agreed critical path milestone events, including delivery of all major equipment, or be subject to proportionately derived liquidated damages, the sum of which would not exceed an agreed upon percentage of the WWT System cost. IDI guaranteed that it would meet mutually agreed-upon WWT System performance parameters or it would repair and/or replace such WWT System components as necessary at its expense until such performance was achieved. The sum of any incurred liability to include liquidated damages or make whole performance obligations was limited to a value of the WWT System cost. 9

10 IDI provided warranty for each equipment component of the WWT System in accordance with its standard warranty provisions for 2 years from Provisional Acceptance or 30 months from receipt of equipment on site, whichever came first. Neither party was liable to the other for any special, incidental or consequential damages in connection to work performed as part of the Project. Other commercial terms and conditions such as scheduling and coordination, confidentiality and exclusivity, insurance, taxes, force majeure, design changes, documentation and audit rights, indemnification, dispute resolution and termination were incorporated into the definitive agreement by mutual agreement and in accordance with accepted industry standards for such clauses. Benefits of a DRS-IDI Open Book Alliance The Open Book approach to project implementation provided the following benefits to the DRS- IDI alliance: Table 2. Benefits of a DRS-IDI Open Book Alliance BENEFIT Open Book, Not-to-Exceed Price IMPACT 1. Given the iterative nature of FGD effluent treatment, this approach provided DRS with an important understanding of cost components. 2. Not-to-exceed price provided a platform for DRS to accurately budget expenses. Interactive Design Approach 1. Allowed for discussions with DRS, Owner s Engineer, and scrubber supplier to refine the total system design from a cost and performance standpoint. 2. Reduced design changes. 3. Expedited schedule. Committed Resources IDI planned and reserved its prime resources and those of its prime sub-contractors for the benefit of DRS s project. 10

11 BENEFIT On-going R&D Validation of Design Alternatives IMPACT 1. Verified design assumptions and calculations prior to detailed engineering and fabrication. 2. Avoided unnecessary changes. 3. Expedited schedule. Operator O&M Interface 1. Optimized layout 2. Optimized design for load and transients. 3. Optimized labor and possible shift utilization. 4. Standardized equipment manufacturer selection. 5. Allowed for better implementation of specific needs to ease maintenance. Regulatory Interface 1. IDI assisted DRS in regulatory discussion of control technology. 2. IDI helped present arguments against over-control. 3. IDI helped formulate strategies for favorable public opinion. Expedited Schedule Minimized Construction Cost Team meetings on the above subjects resulted in faster communication of needs and resolution of issues in an open dialogue format. Engineering design was 100% complete before executing the Construction Contract, thus providing an exact design to eliminate contingencies normally applied by the Construction Contractor. 11

12 Project Execution Throughout the project, weekly meetings, monthly reports and progress milestone invoices were provided to DRS, which included a summary of the hours spent and all the procurement costs. Summary A FGD wastewater treatment system was successfully implemented for Dominion Resources Services (DRS) using the Open Book alliance approach. The overall project costs and schedule were minimized because it recognized the inter-dependent design aspects of three important systems (scrubber, wastewater treatment system and gypsum quality) previously evaluated independently, while eliminating those expenditures associated with uncertainties (i.e., contingencies) normally built into a process design in typical competitive bidding situations. The key features of the Open Book project implementation approach were the following: Owner s Engineer was involved in the design and selection of the scrubber and provided additional advisory services for the design and procurement of the WWT System. The EPC contracting strategy was avoided which resulted in cost savings and an expedited project schedule. Direct interaction between DRS and IDI staff resulted in an optimized WWT System at the lowest possible cost. This highly successful project was commissioned in 2009 and the WWT System met all the performance guarantees. The costs were kept below the target value. References 1. Pudvay, Michael L., Operating Experience on the Treatment of FGD Scrubber Blowdown from Existing Generating Stations, IWC-05-69, San Antonio, TX (2005). 2. Mierzejewski, M.K., Wastewater Management at FGD Installations, Proceedings, 88 th Air and Waste Management Association Conference, San Antonio, TX (1995). Acknowledgements We would like to acknowledge the following individuals for their assistance in preparing this paper: Mr. Dwyane Terrier of Dominion, and Hunter Cox, IDI s Project Manager. 12