Nitrogen Removal in Large Scale Plants. Dimitri Katehis PhD, PE

Transcription

1 Nitrogen Removal in Large Scale Plants Dimitri Katehis PhD, PE May 2009

2 Overview The Basics Understanding Influent Variability and Using it to our Advantage Process Control: From Passive to Feed-Forward Controls Understanding and Managing N 2 O Emissions Sustainable Supplemental Carbon Sources & Reducing Agents Full Scale Application of Anammox Reactors

3 Achieving Denitrification in Wastewater Treatment Plants Exposing Wastewater and Biomass to Alternating Aerobic and Anoxic Conditions Sewage Additional Organic Carbon TREATED EFFLUENT ~ 2hrs ~ 6-8hrs ~ 2hrs ~ 1hr WASTE Biomass Suspended Growth Systems Typically Preferred Relatively Low Capital Cost Sludge Age and Detention Time Fixed Film Systems Sometimes Necessary Temperature, Site Constraints Can Drive The Need for Fixed Film Finicky, Best Applied Where Organic Carbon Feed is Well Characterized

4 Diurnal Influent Loadings to WWTPs Nitrogen and Organics Don t Arrive in WWTPs at the Same Time

5 Managing Organic Carbon Input is Key Refining Supplemental Carbon Addition Strategies m c t Additional Organic Carbon Sewage TREATED EFFLUENT WASTE Biomass Simple Carbon Management Strategies Result in Higher Chemical Costs, Greater Waste Biomass Production and Diminished Process Capacity

6 Carbon Footprint of Advanced Treatment Facility Operations

7 Managing Organic Carbon Input is Key Refining Supplemental Carbon Addition Strategies m c t Additional Organic Carbon Sewage TREATED EFFLUENT WASTE Biomass Recognizing the Impact of Diurnal Loadings Allows for a Simple, Yet Efficient Carbon Management Strategy

8 Managing Organic Carbon Input is Key m c Refining Supplemental Carbon Addition Strategies Feed-Back Loops Sewage Q t Additional Organic Carbon NO 3 -N TREATED EFFLUENT WASTE Biomass Optimizes Performance But Still Overdosing As There is a Detention Time Lag

9 Managing Organic Carbon Input is Key m c Refining Supplemental Carbon Addition Strategies Feed-Forward Loops Sewage Q NH 3 -N t Additional Organic Carbon NO 3 -N TREATED EFFLUENT WASTE Biomass Combining Influent Characteristics and In-Basin Monitoring Maximizes The Capacity that Can be Extracted from a Given System

10 Managing Organic Carbon Input is Key The Adoption of Activated Sludge Models (ASM Family) By the Industry Has Been Critical in Distributing the Knowledge Developed by Our Academics Process Simulation Models Provided a Usable Technology Transfer Mechanism Presentation of Research Results in Simple Matrix Format Using Industry Conventions Allow for Dynamic Time Variant Analysis of Processes 5 Minute Increments.

11 Challenges

12 Direct Emissions: Scope 1 N 2 O Release from Nitrogen Removal N 2 O Produced as an Intermediate In Biological Nitrogen Removal Denitrification: Mechanism Relatively Well Understood N 2 O Produced in Anoxic Zones If Denitrification is Incomplete N 2 O will also be present in Anoxic Zone Effluent Presence of Nitrite A Good Surrogate N 2 O is then stripped into the atmosphere in downstream Aerobic Zone

13 Direct Emissions: Scope 1 N 2 O Release from Nitrogen Removal Nitrification N 2 O Produced When Ammonia Oxidizers are Stressed Chandran et al (2008) Low DO; Elevated Ammonia Concentrations Mechanisms/Pathways Not Well Understood Yet Impact Expected Less than from Denitrification with exception of Sidestream Treatment Processes

14 Direct Emissions: Scope 1 N 2 O Release from Nitrogen Removal From: Water Research, Volume 42, Issue 3, February 2008, Pages Marlies J. Kampschreur, Wouter R.L. van der Star, Hubert A. Wielders, Jan Willem Mulder, Mike S.M. Jetten and Mark C.M. van Loosdrecht

15 Direct Emissions: Scope 1 N 2 O Can Be A Significant Contributor to GHG Inventory

16 Direct Emissions: Scope 1 N 2 O Can Be A Significant Contributor to GHG Inventory Zero Emissions Observed In Plants During Late Afternoon and Evening Hours

17 Direct Emissions: Scope 1 N 2 O Can Be A Significant Contributor to GHG Inventory.But Not for All Plants/Conditions Primary Effluent AX AER AX Aerobic Zone 1

18 The Search for More Sustainable Reducing Agent Organic Carbon Compounds Traditionally Used in Wastewater Treatment Applications Commercially Available Carbon Sources Methanol Ethanol Sugar/Corn Syrup Waste Products (Glycerol from Biodiesel Production.) Identifying and Utilizing Supplemental Carbon Sources That Minimize Cost and Provide Enhance the Sustainability of Operations

19 Using Nitrogen As the Reducing Agent ANAMMOX Reaction Harnessed in Specialized Wastewater Treatment Applications Digested Biosolids Dewatering Liquors Landfill Leachate Concentrated, Warm Streams Ability to Pair with a Nitritation Process 1 NH NO HCO H + Paques BV (2005) = 1.02 N NO CH 2 O 0.5 N H 2 O Three Reactor Configurations Demonstrated in Full Scale Upflow Anaerobic Sludge Bed (UASB) Fixed Film Nitritation/ANAMMOX Suspended Growth Nitritation/ANAMMOX

20 Some Initial Thoughts Optimization of Denitrification Process Component Hinges on Management of Reducing Agent Inherent Wastewater Organics Supplementing Reducing Agent Next Generation of Reducing Agents Sulfur Based Systems? Understanding Dynamics of N 2 O Production and Emission Population Interactions?? ANAMMOX Based Systems Cold-Startup Experiments Indicate Organisms are Far More Diverse and PRESENT!