Nutrient Removal - Total Phosphorus Study Guide
Nutrient Removal - Total Phosphorus Study Guide
Overview
Purpose: This guide is designed to help wastewater operators prepare for the certification exam and serve as a reference for nutrient removal, particularly total phosphorus. It consists of key knowledge concepts necessary for understanding wastewater treatment processes targeting phosphorus control.
Preface
Learning Strategy:
Study Material: Read all key knowledge until memorized.
Collaborative Learning: Engage in classes related to wastewater operations.
Further Research: Explore references provided at the guide’s end for deeper understanding.
Certification Examination: Testing will be multiple-choice, with questions drawn directly from the key knowledge concepts.
Acknowledgements
This guide developed from collaborative efforts among various stakeholders, including wastewater operators, trainers, and the Wisconsin Department of Natural Resources (WDNR).
Table of Contents
Part 1 - Biological Removal
Theory and Principles
Operation and Maintenance
Monitoring, Process Control, and Troubleshooting
Safety
Calculations
Part 2 - Chemical Removal
Theory and Principles
Operation and Maintenance
Monitoring, Process Control, and Troubleshooting
Safety and Regulations
Calculations
Part 1 - Biological Removal
Chapter 1 - Theory and Principles
Section 1.1 - Definitions
Aerobic: Condition with available free and dissolved oxygen (DO) in an aqueous environment.
Anaerobic: Condition lacking free, dissolved, and combined oxygen in an aqueous environment.
Anoxic: Condition where oxygen exists only in combined forms (e.g., nitrate, nitrite, sulfate) in an aqueous setting.
Fermentation: Bacterial breakdown of organic matter in anaerobic conditions (e.g., in collection systems, primary clarifiers).
Glycogen: Energy storage polysaccharide in cells; impactful in biological phosphorus removal (EBPR).
PAOs (Phosphate-Accumulating Organisms): Bacteria that uptake orthophosphate beyond their biological needs.
PHAs (Polyhydroxyalkanoates): Energy-rich carbon polymers synthesized by bacteria from organic molecules like volatile fatty acids (VFAs).
Poly-P (Polyphosphate): Chains of phosphate groups that PAOs can accumulate, facilitating EBPR.
Selector: Component of the treatment system that provides favorable environments for specific microorganisms.
Each parameter must be learned and understood thoroughly for the certification exam.
Section 1.2 - Wastewater Characteristics
Selector Hydraulic Retention Time (HRT): Time required for wastewater to pass through a tank.
Sludge Age: Duration activated sludge remains in treatment (measured in days).
Soluble BOD (Biochemical Oxygen Demand): BOD after filtration through a 0.45 μm filter, indicating readily fermentable material.
Substrate: Organic matter or nutrients necessary for microorganisms' growth (e.g., VFAs for PAOs).
TFO (Treatment Facility Overflow): Unpermitted release of wastewater from a facility; must be reported within 24 hours.
VFAs (Volatile Fatty Acids): Smaller organic molecules generated during fermentation, crucial as PAO food sources.
Section 1.3 - Biological Principles
BOD/TP Ratio: A minimum BOD/TP ratio of 20:1 or COD/TP ratio of 45:1 is necessary for successful EBPR.
VFA Utilization: PAOs require VFAs to produce and store PHAs, which facilitates phosphorus removal.
I/I Effects: Infiltration/inflow (I/I) can dilute organic matter and reduce VFA content, negatively affecting EBPR effectiveness.
EBPR Process: Employs alternating anaerobic and aerobic zones, supporting PAOs’ growth through phosphorus accumulation.
Section 1.4 - Performance Limiting Factors
Environmental Conditions: Presence of nitrate or DO in anaerobic zones inhibits PAOs, affecting phosphorus release and uptake processes.
Nitrification Impact: Nutrient cycles must be managed to prevent excessive nitrate levels, which can hinder EBPR.
Chapter 2 - Operation and Maintenance
Section 2.1 - Definitions
Denitrification: Conversion of nitrate to nitrogen gas by bacteria under anoxic conditions.
Nitrification: Conversion of ammonia to nitrites and then nitrates by nitrifying bacteria under aerobic conditions.
Struvite: Compound formed by magnesium, ammonium, and phosphate; can cause operational issues.
HRT: Vital for ensuring adequate contact time between microorganisms and nutrients for EBPR.
Section 2.2 - Reactors
Different EBPR configurations (e.g., A/O, A2/O, modified Bardenpho, etc.) utilize various reactor styles while adhering to EBPR principles.
Section 2.3 - Methods
Operating Parameters: Proper sludge age and HRT are essential for maximizing PAO benefits; typical ages are between 5 to 30 days for EBPR plants.
Chapter 3 - Monitoring, Process Control, and Troubleshooting
Section 3.1 - Definitions
Total Phosphorus: Combination of all phosphorus forms in wastewater, essential for process control.
Orthophosphate: Soluble form of phosphorus crucial for monitoring and process adjustments.
Section 3.2 - Sampling and Testing
Regular sampling at influent, effluent, and various system points is crucial for maintaining control in phosphorus removal processes.
Section 3.3 - Data Understanding and Interpretation
Operators must recognize the significance of phosphorus removal efficiencies and sludge characteristics to optimize treatment.
Part 2 - Chemical Removal
Chapter 6 - Theory and Principles
Section 6.1 - Definitions
Alkalinity: Key for wastewater's ability to neutralize acids; impacts phosphorus precipitation.
Chemical Precipitation, Coagulation, Flocculation, Crystallization: Processes related to phosphorus removal.
Eutrophication: Environmental effect of excess nutrients leading to aquatic overgrowth.
Chapter 8 - Monitoring, Process Control, and Troubleshooting
Operators should maintain careful records of chemical usage and effluent phosphorus metrics to ensure compliance with regulations.