Guidance Document on Anaerobic Digester Foaming Prevention and Control Methods.

Cover -- Copyright -- Acknowledgments -- Abstract and Benefits -- Table of Contents -- List of Tables -- List of Figures -- List of Acronyms -- Executive Summary -- Chapter 1.0: Guidance Document on Anaerobic Digester Foaming Prevention and Control Methods -- 1.0 Introduction -- 1.1 Background and Basis of AD Foaming -- 1.2 Methodology of Managing Foam Episodes -- Chapter 2.0: Step 1: Symptom and Problem Identification (Diagnosis) -- Chapter 3.0: Step 2: Identification of Foaming Causes/Contribution -- 3.1 Historical Data Evaluation -- 3.1.1 OLR/OLR Variations to Digesters -- 3.1.1.1 Feed Flow Rate to Digesters -- 3.1.1.2 VS Loading Rate to Digesters -- 3.1.1.3 Frequency of Digester Feeding/Variations in OLR -- 3.1.1.4 Ratio of Primary Sludge to Waste Activated Sludge (PS:WAS) Solids in Feed Sludge -- 3.1.2 pH/Volatile Acids/Alkalinity -- 3.1.3 Gas Production/Pressure -- 3.1.4 Temperature -- 3.2 Sampling for Foaming Potential Measurement and Foam Causing Constituents -- 3.2.1 Sampling, Storage, and General Considerations -- 3.2.2 Experimental Protocols -- 3.2.3 Physical Methods - Foam Potential (Pagilla et al., 1997) -- 3.2.4 Biological Methods -- 3.2.4.1 Gram Stain Procedure -- 3.2.4.2 FISH Analysis -- 3.3 Long-Term Monitoring/Detection of Foam Events -- 3.3.1 Foam Detection by Monitoring and Testing of Digesters or Contents -- 3.3.2 Detection Using Sensors and Associated Instrumentation -- 3.3.3 Examples of Specific In-House Foam Detection/Monitoring Methods -- 3.3.3.1 Foam Separator Drain Temperature Difference -- 3.3.3.2 Foam Monitoring and Sensing by Pressure/Level Sensors -- Chapter 4.0: Step 3: Prevention and Control Methods -- 4.1 Sludge Disintegration Methods (WAS Pre-Treatment Methods) -- 4.1.1 Acid Phase Digestion (Biological Lysis) -- 4.1.2 Physical Lysis -- 4.1.2.1 Considerations for Sludge Disintegration Alternatives.

4.2 Operational Modifications to Prevent or Control Foaming -- 4.2.1 Digester Feed Flow Rate and Quality Maintenance -- 4.2.2 Mixing -- 4.2.2.1 Mixing Optimization -- 4.2.2.2 Depth Sampling of Digesters -- 4.2.3 Liquid Level and Feed Flow Adjustment During a Foaming Event -- 4.3 Control of the Digester Physical Features -- 4.3.1 Gas Piping -- 4.3.2 Foam Suppression Nozzle Installation -- 4.3.3 Automated Defoamer Addition -- 4.4 Control of Filamentous Foaming -- 4.4.1 Control of the Secondary Treatment Process and Associated WAS Foaming -- 4.4.1.1 Solids Retention Time (SRT) Control -- 4.4.1.2 Selectors -- 4.4.1.3 Surface Wasting -- 4.4.2 Influent FOG Control -- 4.4.3 Chemical Methods -- 4.4.3.1 Oxidizing Chemicals -- 4.4.3.2 Antifoams/Defoamers -- 4.4.3.3 Polymers/Salts -- 4.5 Digester Foam Mitigation Recommendations -- 4.5.1 Other Considerations -- References.

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Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, 2024. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries.