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Stabilization Pond Systems Manual

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Stabilization Pond Systems Manual 2013 Stabilization Pond Systems Operations • Maintenance • Management Minnesota Pollution Control Agency 520 Lafayette Road North St. Paul, Minnesota 55155-4194 651-296-6300 • 800-657-3864 Authors Original authors: Williard N. Sexauer, Roger V. Karn 2013 edition: Gene Erickson, Kay Curtin, Steve Duerre Contributors to editions 1975, 1979, 1994, 1996, 1999 Janet Eckart, Gene Erickson, Linda Grant, Del Haag, Mike Herman, Dianne Navratil, Dwayne Nelson, Brian Roach Acknowledgements Wastewater training staff appreciate the attendees of stabilization pond training courses beginning in January, 1974; their comments and suggestions have been incorporated into this manual. Editing and Graphic Design Graphic design: Carol Pruchnofski, Nancy Ellefson Editor: Nancy Ellefson Cover photo: City of Albany, Minnesota Courtesy of Stantec Consulting Services The stabilization pond at Albany, constructed in 1955, was the first such system in Minnesota. The system was upgraded in 1984 with construction of the two pond cells in the background. The pre-aeration pond was added in 2001. Minnesota Pollution Control Agency 520 Lafayette Road North | Saint Paul, MN 55155-4194 | www.pca.state.mn.us | 651-296-6300 Toll free 800-657-3864 | TTY 651-282-5332 wq-wwtp8-22 Forward This manual was developed to help wastewater operators understand how wastewater is treated in stabilization ponds. It is intended to provide a comprehensive guide for an operator to follow during normal operation and maintenance. Although many practices covered in this manual can be used for all types of ponds, information does not specifically include aerated ponds, polishing ponds or storage lagoons. This manual is NOT intended to replace various procedures and requirements contained in your NPDES permit; it only serves as guidance to the user. In cases where there are differences, your NPDES permit is the final governing document and should be relied upon for compliance purposes. The manual is organized to follow the normal flow of wastewater after its discharge to a sanitary sewer system, including collection system operation and maintenance. Disclaimer Any references to commercial products are for illustration purposes only and do not constitute endorsement by the Minnesota Pollution Control Agency or the State of Minnesota. Dedication The Minnesota Pollution Control Agency (MPCA) began offering wastewater operator training in the early 1970s under the leadership of the operator training group’s first supervisor, Bill Sexauer. Bill’s vision included not only mandatory wastewater operator certification, but also specific training for stabilization pond operators and others. As a result, the first pond seminar was held in January, 1974. Because of Bill’s leadership and wisdom and based on experience from those seminars, this manual was first created in 1975. Although Bill passed away on March 14, 2010, his legacy of pond seminars continues. This manual is dedicated to Willard (Bill) Sexauer. Stabilization Pond Systems Operation, Maintenance, Management | i ii | ©2013 Minnesota Pollution Control Agency All rights reserved. Contents Contents 1. Introduction to stabilization ponds ............................................ 1 2. Wastewater collection systems ................................................ 19 3. Lift stations ............................................................................... 29 4. Stabilization ponds treatment process ..................................... 37 5. Design criteria ........................................................................... 51 6. Stabilization pond operation .................................................... 61 7. Discharging stabilization ponds ................................................ 81 8. Maintenance ............................................................................ 95 9. Sampling and lab testing ........................................................ 109 10. Records and reports ............................................................... 117 11. Safety ...................................................................................... 125 12. Personnel ................................................................................ 133 13. Troubleshooting ...................................................................... 139 14. Appendix ................................................................................ 149 A: Pump calibration procedure & worksheet ........................ 151 B: Emergency notification ..................................................... 155 C: Solving word problems & design problems 1 & 2 ............. 157 D: Total days needed to discharge ......................................... 161 E: Discharge calculation worksheet ....................................... 163 F: Discharge evaluation report ............................................ 165 G: Dilution ratio worksheet ................................................... 167 H: MPCA regional offices ....................................................... 169 I: Various pond worksheets & spreadsheets ........................ 171 J: References and suggested resource material .................... 187 Stabilization Pond Systems Operation, Maintenance, Management | iii iv | ©2013 Minnesota Pollution Control Agency All rights reserved. 1 — Introduction Introduction to Stabilization Ponds Characteristics of wastewater ................................................ 3 Commonly-measured parameters .......................................... 5 1Biological organisms ............................................................... 6 Overview of wastewater treatment ....................................... 7 Management and operator responsibility ............................ 13 Effluent quality limits............................................................ 14 Total Maximum Daily Load (TMDL) ...................................... 14 Unauthorized releases (bypassing) ....................................... 15 Upsets ................................................................................... 16 Effluent violation .................................................................. 17 Written reports ..................................................................... 17 Significant industrial users .................................................... 17 NPDES permit provisions ...................................................... 18 Public health concerns ......................................................... 18 Stabilization Pond Operation and Maintenance | 1 1 — Introduction 2 | ©2013 Minnesota Pollution Control Agency All rights reserved. 1 — Introduction Chapter 1 — Introduction Characteristics of wastewater Wastewater is water that has been degraded or contaminated. It generally contains 99.9 percent water and 0.1 percent solids. Sources of wastewater include: • Human and animal wastes • Household wastes • Infiltration of ground water • Inflow of surface waters (rain water) • Various industrial wastes Physical characteristics The physical characteristics of wastewater – color, odor, temperature, flow, solids – can tell you a lot about the type of waste you are receiving at your facility as well as warn you of developing problems. • Color – The color of normal domestic wastewater is gray, resembling dirty dishwater. A black color may indicate septic (no oxygen) conditions or certain types of industrial loading. Many color variations can occur. If you know the source and nature of the wastewater, you can often use color as a tool to assist you in operating your facility. • Odor – The odor of fresh domestic wastewater is often described as musty. A rotten egg odor (hydrogen sulfide) indicates septic conditions. • Temperature – The normal influent temperature of domestic wastewater is a few degrees warmer than the water supply. Higher temperatures may indicate industrial cooling water discharges. Cooler water may indicate excessive infiltration or inflow water. • Flow – The variation in flow in a community may be extreme, especially in smaller cities. The impact of this variation may cause severe problems depending on the type of wastewater treatment plant you operate. • Solids – Wastewater is 99.9 percent water and 0.1 percent solids. It is the 0.1 percent solids that creates the need for wastewater treatment facilities. Types of solids Solids in wastewater are classified by their characteristics. • Total solids includes all solids: suspended, dissolved, and floating solids. Each person contributes an average of 0.5 pounds of total solids per day to the waste stream. • Suspended solids are visible; they are hanging (in suspension) in the water. They are normally removed by a sedimentation or filtration process. Typical domestic wastewater contains about 200-250 mg/L of suspended solids, with each person Stabilization Pond Operation and Maintenance | 3 1 — Introduction contributing about 0.2 pounds suspended solids per day to the wastewater stream. Suspended solids can be divided into settleable solids and colloidal solids. • Settleable solids are those solids that are of sufficient weight and size to settle in a period of one hour. Primary clarifiers do most of the work of removing settleable solids. • Colloidal solids are the solids that remain uniformly dispersed throughout the water and do not settle. • Dissolved solids are in solution (dissolved) in the wastewater. An example of a dissolved solid is a teaspoon of sugar stirred into a glass of water. You cannot see the sugar; however, it is present in
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