Under the Direction of the MOP 11 Subcommittee of the Technical Practice Committee

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1 Operation of Municipal Wastewater Treatment Plants WEF Manual of Practice No. 11 Chapter 25 Process Performance Improvements Sixth Edition Prepared by the Operation of Municipal Wastewater Treatment Plants Task Force of the Water Environment Federation Michael D. Nelson, Chair Zafar I. Bhatti, Ph.D., P. Eng. G. Michael Coley, P.E. Zeynep K. Erdal, Ph.D., P.E. Charles G. Farley Peter L. LaMontagne, P.E. Daniel A. Nolasco, M. Eng., M. Sc., P. Eng. George R. Schillinger, P.E., DEE Timothy H. Sullivan, P.E. Under the Direction of the MOP 11 Subcommittee of the Technical Practice Committee 2007 Water Environment Federation 601 Wythe Street Alexandria, VA USA 1

2 About WEF Formed in 1928, the Water Environment Federation (WEF) is a not-for-profit technical and educational organization with 32,000 individual members and 80 affiliated Member Associations representing an additional 50,000 water quality professionals throughout the world. WEF and its member associations proudly work to achieve our mission of preserving and enhancing the global water environment. For information on membership, publications, and conferences, contact Water Environment Federation 601 Wythe Street Alexandria, VA USA (703) IMPORTANT NOTICE The material presented in this publication has been prepared in accordance with generally recognized engineering principles and practices and is for general information only. This information should not be used without first securing competent advice with respect to its suitability for any general or specific application. The contents of this publication are not intended to be a standard of the Water Environment Federation (WEF) and are not intended for use as a reference in purchase specifications, contracts, regulations, statutes, or any other legal document. No reference made in this publication to any specific method, product, process, or service constitutes or implies an endorsement, recommendation, or warranty thereof by WEF. WEF makes no representation or warranty of any kind, whether expressed or 2

3 implied, concerning the accuracy, product, or process discussed in this publication and assumes no liability. Anyone using this information assumes all liability arising from such use, including but not limited to infringement of any patent or patents. Copyright 2007 by the Water Environment Federation All Rights Reserved. Water Environment Research, WEF, and WEFTEC are registered trademarks of the Water Environment Federation. 3

4 Manuals of Practice of the Water Environment Federation The WEF Technical Practice Committee (formerly the Committee on Sewage and Industrial Wastes Practice of the Federation of Sewage and Industrial Wastes Associations) was created by the Federation Board of Control on October 11, The primary function of the Committee is to originate and produce, through appropriate subcommittees, special publications dealing with technical aspects of the broad interests of the Federation. These publications are intended to provide background information through a review of technical practices and detailed procedures that research and experience have shown to be functional and practical. Water Environment Federation Technical Practice Committee Control Group B. G. Jones, Chair J. A. Brown, Vice-Chair S. Biesterfeld-Innerebner R. Fernandez S. S. Jeyanayagam Z. Li M. D. Nelson S. Rangarajan E. P. Rothstein A. T. Sandy A. K. Umble T. O. Williams J. Witherspoon 4

5 Contents Chapter 25 Process Performance Improvements Introduction, Purpose, Background, Chapter Organization Introduction Purpose Background Chapter Organization Steps of Process Performance Improvement Objectives Resources Labor and Equipment Schedule Capabilities of Existing Facility Process Layout Data Collection and Analysis Data Collection Methodology Data Analysis and Process Loadings Process Capacity Diagram Reassess Flow Meters Accuracy Vital to Program Field Calibration Dye Testing Techniques Fill and Draw Test Redundant Instrumentation Hydraulic Modeling Testing and Analysis Tools Hydraulic Capacity Analysis Hydraulic Capacity General Capacity Exceedance Indicators Hydraulic Bottlenecks 5

6 Flow Splitting Imbalances The Use of Hydraulic Modeling Techniques Tracer Testing Aeration System Analysis Oxygen Transfer Tests Techniques Used to Determine Oxygen Transfer Off-Gas Analysis Hydrogen Peroxide Test ASCE Clean Water Test Aeration Electrical Efficiency Empirical Equations/Modeling Meeting Oxygen Demand Reducing Aeration Energy Consumption Chemical Addition Introduction Limited Plant Capacity Energy Consumption Impacts of Chemical Application Plant Wide Chemical Selection Obtaining Industry Experience Plant testing Assuring Process Compatibility Defining Byproducts and Residuals Management Considerations Selecting Points of Application Selecting Dosing Control Options Confirming Availability Defining Storage and Handling Requirements Determining Environmental Effects Defining Costs Ongoing Performance 6

7 Examples Primary Treatment Secondary Treatment Polymers Chlorine Soda Ash and Caustic Soda Disinfection Lagoons Thickening Anaerobic Digestion Aerobic Digestion Bioaugmentation Minimizing Impact of Solids Recycle Streams Appendix 1 Flow Meter Background Information Flow Meter Types Open Channel Meters Full Pipe Flow Meters Troubleshooting Open Channel Meters Full Pipe Flow Meters Accuracy Appendix 2 Off Gas Analysis Testing Trials Appendix 3 Hydrogen Peroxide Testing Details Appendix 4 ASCE Clean Water Test Appendix 5 Case-History Tracer Testing Anaerobic Digester References 7

8 LIST OF TABLES 25.1 Common unit process loading and operational parameters 25.2 Historical data review findings and derived process performance improvement tasks 25.3 Factors affecting oxygen transfer 25.4 Chemical dosage guide for wastewater treatment 25.5 Sample calculation for estimating sludge mass 25.6 Basis for sludge mass calculation 25.7 Additional sludge to be handled with chemical treatment systems: phosphorus removal by mineral addition to secondary plants 25.8 Criteria for selecting chemical addition locations 25.9 Environmental effects of chemical discharges Effects of polymer addition to primary clarifier on process performance Effects of lime addition on primary clarifier performance Possible treatment applications of bioaugmentation products Flow metering equipment commonly used in wastewater treatment facilities Flow metering equipment common installation concerns Examples of when to use the off-gas test Examples of when to use the hydrogen peroxide test Examples of when to use the clean water test Summary of results for mixing tests in digester No. 1 and No. 2 8

9 LIST OF FIGURES 25.1 Simplified outline of the steps involved in process performance improvement 25.2 Typical task flows 25.3 Unit process capacity 25.4 Offgas analyzer 25.5 Tracer study results for digester no Tracer study results for digester no Completely stirred tank reactor with an initial Li concentration equal to that measured immediately after lithium addition 25.8 Lithium washout curve fitted to a simple CSTR model 25.9 Lithium washout curve for digester no. 1 fitted to a simple CSTR model Completely stirred tank reactor combined with a bypass line directed to a small CSTR Results for digester no. 2 using the model shown in Figure

10 Preface This sixth edition of this chapter was produced under the direction of Michael D. Nelson, Chair. The principal author of this chapter is Daniel A. Nolasco, M. Eng., M. Sc., P. Eng. Michael D. Nelson served as the Technical Editor of this chapter. Tony Ho and Dr. Mano Manoharan, Standards Development Branch, Ontario Ministry of the Environment, Canada, and Dr. Glen Daigger, CH2M HILL, collaborated in the successful development of the methodologies presented in the chapter. This chapter has been completely rewritten. It outlines the steps of process performance improvement. An important relevant topic, flow meter accuracy, is discussed. Next, tools used to define the process performance of the existing facility are presented. They include hydraulic capacity analysis, tracer testing, and aeration system analysis. Embedded in the tools are approaches to improve process performance. A section then follows on chemical addition. Chemical selection steps are detailed in addition to examples of process performance improvements. Next, a section on bioaugmentation is presented. Appendices are included to fully explain flow meters and aeration system analysis and present a tracer case history. Authors' and reviewers' efforts were supported by the following organizations: American Bottoms Regional Wastewater Treatment Facility, Sauget, Illinois CH2M HILL, Santa Ana, California 10

11 Environmental Assessment and Approvals Branch, Ministry of Environment, Toronto, Ontario, Canada Hubbell Roth & Clark, Detroit, Michigan Mike Nelson Consulting Services LLC, Churchville, Pennsylvania NOLASCO & Assoc. Inc., Ontario, Canada NYSDEC, Albany, New York Peter LaMontagne, P.E., New Britain, Pennsylvania 11