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American Society ©f Civil Engineers

Standard Guidelinesfor In-Process Oxygen

Transfer Testing

Published by^B| jjjj?jjj^jjS American Society5=i]viiPii JE of Civil Engineers

345 East 47th StreetNew York, NY 10017-2398

ASCE-18-96



Abstract:

This Standard Guidelines for In-Process Oxygen Transfer Testing describes several proventechniques for measuring oxygen transfer under process conditions. Nonsteady state, offgas, andinert gas tracer methods are detailed in the body of this standard, which is followed by a briefdiscussion of comparisons among methods. It is intended that these guidelines be used byengineers, owners, and manufacturers in evaluating the performance of aeration devices underprocess conditions.

Library of Congress Cataloging-in-Publication Data

Standard guidelines for in-process oxygen transfer testing.p. cm.Prepared by the ASCE Oxygen Transfer Standards Subcommittee.ISBN 0-7844-0114-41. Aeration tanks—Testing. 2. Water—Aeration—Evaluation. I. American Society of CivilEngineers. Oxygen Transfer Standards Subcommittee.TD758.S73 1997 97-8344628.1'65-dc21 CIP

Photocopies. Authorization to photocopy material for internal or personal use undercircumstances not falling within the fair use provisions of the Copyright Act is granted by ASCEto libraries and other users registered with the Copyright Clearance Center (CCC) TransactionalReporting Service, provided that the base fee of $4.00 per article plus $.50 per page is paiddirectly to CCC, 222 Rosewood, Drive, Danvers, MA 01923. The identification for ASCEBooks is 0-7844-0114-4/97/$4.00 + $.50 per page. Requests for special permission or bulkcopying should be addressed to Permissions & Copyright Dept, ASCE.

Copyright © 1997 by the American Society of Civil Engineers,All Rights Reserved.Library of Congress Catalog Card No: 97-8344ISBN 0-7844-0114-4Manufactured in the United States of America.



Standards

In April 1980, the Board of Directors approvedASCE Rules for Standards Committees to governthe writing and maintainance of standards devel-oped by the Society. All such standards are devel-oped by a consensus standards process managed bythe Management Group F (MGF), Codes and Stan-dards. The consensus process includes balloting bythe balanced standards committee made up of So-ciety members and non-members, balloting by themembership of ASCE as a whole, and balloting bythe public. All standards are updated or reaffirmedby the same process at intervals not exceeding fiveyears.

The following standards have been issued:

ANSI/ASCE 1-82 N-725 Guidelines for Design andAnalysis of Nuclear Safety Related Earth Struc-tures

ANSI/ASCE 2-91 Measurement of Oxygen Transferin Clean Water

ANSI/ASCE 3-91 Standard for the Structural De-sign of Composite Slabs and ANSI/ASCE 9-91Standard Practice for the Construction and In-spection of Composite Slabs

ANSI/ASCE 4-86 Seismic Analyis of Safety RelatedNuclear Structures

Building Code Requirements for Masonry Structures(ACI530-95/ASCE5-95/TMS402-95) and Spec-ifications for Masonry Structures (ACI530.1-95/ASCE6-95/TMS602-95)

Specifications for Masonry Structures (ACI520-95/ACSE6-95/TMS602-95)

ANSI/ASCE 7-95 Minimum Design Loads for Build-ing and Other Structures

ANSI/ASCE 8-90 Standard Specification for the De-sign of Cold-Formed Stainless Steel StructuralMembers

ANSI/ASCE 9-91 listed with ASCE 3-91ANSI/ASCE 10-90 Design of Latticed Steel Trans-

mission StructuresANSI/ASCE 11-90 Guideline for Structural Condi-

tion Assessment of Existing BuildingsANSI/ASCE 12-91 Guideline for the Design of Ur-

ban Subsurface DrainageASCE 13-93 Standard Guidelines for Installation of

Urban Subsurface DrainageASCE 14-93 Standard Guidelines for Operation and

Maintainance of Urban Subsurface DrainageANSI/ASCE 15-93 Standard Practice for Direct De-

sign of Buried Precast Concrete Pipe Using Stan-dard Installations (SIDD)

ASCE 16-95 Standard for Load and Resistance Fac-tor Design (LRFD) of Engineered Wood Con-struction

ASCE 18-96 Standard Guidelines for In-Process Oxy-gen Transfer Testing

ASCE 20-96 Standard Guidelines for the Installa-tion of Pile Foundations

ASCE 21-96 Automated People Mover Standards —Part 1

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Foreword

These guidelines for testing oxygen transfer de-vices in process water are the result of field testing bythe ASCE Oxygen Transfer Standards Committee sinceabout 1979. A significant portion of the early work bythe Committee was supported by grants from the USEnvironmental Protection Agency.

Preparation of these guidelines has been difficult.Side-by-side testing of a number of methods has beenused to verify reproducibility of those techniques and hasled to substantial refinement in procedures and rejectionof some techniques. The methods selected have provento be most reliable under rigorous field conditions. Thetechnology continues to remain dynamic, however, andmodifications and/or new procedures are likely to occurin the future.

It is intended that these guidelines be used by en-gineers, owners, and manufacturers in evaluating theperformance of aeration devices under process condi-tions. They are not intended for compliance testing ofaeration devices insofar as performance under processconditions is affected by a large number of process vari-

ables and wastewater characteristics that are not easilycontrolled. In-process testing does provide the engi-neer with useful information that can be used in futuredesign. It provides the owner with data that can beused for operation and maintenance of the aerationequipment. These procedures provide manufacturerswith a useful research and development tool for theirequipment development and design.

The procedures as a whole are applicable for alloxygen transfer devices in suspended growth systems.They may also be applicable to testing oxygen transferdevices in lakes and streams. They are not applicable tofixed film reactors, although modification of some of themethods might serve to provide data on these processesas well. The substance of the guidelines is based onthe report, "Development of Standard Procedures forEvaluating Oxygen Transfer Devices," EPA 600/2-83-102,October 1983. Throughout this document, however,other pertinent references are provided dealing withmore detail about the techniques. Section 5.0 providesa discussion on the comparison of the methods.

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Acknowledgments

The American Society of Civil Engineers acknowl-edges the devoted efforts of the Oxygen Transfer Stan-dards Committee of the Codes & Standards Activ-ity Council, Water Resources Standards Council. TheGroup is comprised of individuals from many back-grounds, including consulting engineering, research, ed-ucation, wastewater equipment manufacturing, govern-ment, industry, and private practice.

The contributions of USEPA for workshops, lab-

oratory and field studies that support the developmentand refinement of these guidelines is gratefully acknowl-edged.

This standard was formulated through the consen-sus standards process by balloting in compliance wth theprocedures of the ASCE Codes and Standards ActivityCouncil. Those individuals who serve on the Committeeon Oxygen Transfer Standards are:

C. R. BaillodEdwin L. BarnhartHenry H. Benjes, Jr.Marshall BlomquistArthur G. BoonWilliam C. Boyle, ChairRichard C. BrennerHaskel BrocinerLinfield C. BrownHugh J. Campbell, Jr.Paul Cummings, Jr.Lloyd EwingGeorge R. FisetteWilhelm FreyGary GilbertRam A. GoelMervyn C. GoronszyPeter GrossAlain HeduitRobert HookJohn Hunter, IIIRobert L. IrvineRolf G. KayserBoris M. Khudenko

Mikkel G. MandtFrederick K. MarotteJames J. MarxMikael MedelbergHenry K. MelcerJames A. MuellerWayne L. PaulsonDavid RedmonMichael G. RiethThomas C. RooneyRobert E. ShekerGerald ShellJoseph H. SherrardOle SinkjaerGordon SpeirsVernon T. StackH. David StenselMichael K. StenstromMartin WagnerRobert S. WatralJerome D. WrenShang W. YuanFred W. Yunt

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Contents

1 Scope 12.0 Non-Steady State Method 1

2.1 Objective 12.2 Theoretical basis 12.3 Assumptions and limitations 22.4 Procedure 3

2.4.1 The H2O2 technique 32.5 Sample calculation 42.6 Quality control 52.7 Test variability and accuracy 6

2.7.1 Test variability 73.0 Off-gas Method 9

3.1 Objective 93.2 Theoretical basis 93.3 Assumptions and limitations 103.4 Apparatus and supplies 10

3.4.1 Off-gas analyzer 103.4.2 Off-gas collection system 11

3.5 General requirements of apparatus 113.5.1 Off-gas collection system 113.5.2 Off-gas analyzer capabilities 113.5.3 Liquid phase DO hardware 123.5.4 Miscellaneous equipment 12

3.6 Procedure 123.6.1 Conduct of test 123.6.2 Analyzer operation 123.6.3 Sampling criteria 133.6.4 Recorded data 13

3.7 Off-gas calculations 133.7.1 General 133.7.2 Summary data sheet 133.7.3 Ancillary information 143.7.4 Report of results 14

3.8 Quality assurance/quality control procedures 143.8.1 Leak test of analyzer module and conduit hose 143.8.2 Oxygen sensor calibration 143.8.3 Sample plan adequacy 14

3.9 Accuracy and precision 144.0 Tracer Measurement of Oxygen Transfer 15

4.1 Objective 154.2 Theoretical basis 154.3 Assumptions and limitations 164.4 Apparatus 17

4.4.1 Liquid scintillation spectrophotometer 174.4.2 Grab sampling device 174.4.3 Alternate continuous-flow sampling arrangement 17

4.5 Procedures 174.5.1 Tracer quantities 174.5.2 Tracer release 174.5.3 Sampling locations, test durations, and sampling frequency 18

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4.5.4 Sample collection, storage, and shipment 184.5.4.1 Grab sampling 184.5.4.2 Continuous flow sampling 18

4.5.5 Laboratory analysis 184.6 Calculations J 9

4.6.1 General 194.6.2 Example 19

4.7 Quality assurance/quality control procedures 214.8 Accuracy and precision 21

5.0 Comparisons Between Field Oxygen Transfer Techniques 22

AppendicesA Off-Gas Analyzer 26

A.1.0 Capabilities 26B Sample Calculations for Off-Gas Technique 28

B.I Example 1 28B.2 Example 2: Computing the mean weighted average (MWA) OTE/ and SOTEpw 31

C Corrections to KLaf Ratio for Krypton Stripping 33D Symbols and Nomenclature 34E Other Methods 36

E.I Steady State Method 36E.I.I Objective 36E.1.2 Theoretical basis 36E.I.3 Assumptions and limitations 36E.1.4 Procedure 36

E.1.4.1 General 36E.1.4.2 Oxygen uptake rates - Ex situ 37E.1.4.3 Oxygen uptake rates - Other methods 37E.1.4.4 Sample calculation 39E.1.4.5 Quality control 39E.I.4.6 Test variability and accuracy 39

E.2 Mass Balance 40E.2.1 Objective 40E.2.2 Theoretical basis 40E.2.3 Assumptions and limitations 40E.2.4 Procedures 41

E.2.4.1 Driving force factor 42E.2.4.2 Saturation and temperature correction 42E.2.4.3 Nitrification-denitrification factor 42E.2.4.4 Benthal oxygen demand 42E.2.4.5 Surface rearation 42E.2.4.6 Photosynthetic factor 42

E.2.5 Example calculation 43E.2.6 Accuracy and precision 44E.2.7 Activated sludge systems 44

E.3 Aeration System Monitering Methods 46E.3.0 Objective 46E.3.1 Theoretical basis and procedure 46

Index 49

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American Society of Civil EngineersStandard Guidelines for In-Process Oxygen Transfer Testing

1.0 Scope1.1 The methods described under these standardguidelines provide several proven techniques for mea-suring oxygen transfer under process conditions. Non-steady state, offgas, and inert gas tracer methods aredescribed in the body of this manual, which is followed bya brief discussion of comparisons among methods. Themethods presented are considered to be well developedand provide satisfactory precision for a wide range of aer-ation processes in suspended growth biological systems.Because a wide range of process variables and wastewa-ter characteristics which impact the precision (and accu-racy) of these methods are difficult to control, the meth-ods are offered as standard guidelines and are not recom-mended for compliance testing of aeration equipment.

2.0 Non-steady State Method

2.1 Objective This section describes a method to de-termine the average oxygen transfer coefficient, K^Uf,for an aeration tank under actual process conditionsby measuring the DO concentration over time aftera perturbation from the steady state condition. It isrecommended that the pertubation be obtained usingH2O2, instead of by changing the power level, to pre-serve hydrodynamics and allow higher incremental DOincreases.

2.2 Theoretical basis The theoretical basis for thismethod is derived from consideration of a mass balance

around a completely mixed aeration tank under steadystate and non-steady state process conditions. The samemechanism applies for (i) O^ transfer into wastewater,when the DO is less than the steady state equilibriumvalue, and (2) for 02 stripping from the wastewater,when the DO is greater than the steady state equilibriumvalue. Note that this technique measures the oxygentransfer coefficient. It is not directly applicable for strip-ping other gases, which may have different molecularsizes and diffusion rates as well as significant gas sideresistances. Kayser (1967, 1969, 1979) was the firstresearcher to apply this technique in testing aerationequipment under process conditions.

2.2.1 A mass balance for oxygen around a com-pletely mixed aeration tank, as shown in Figure 1, isdetermined by the equation

(l)f

Dividing by V and l e t t i n g y i e l d s the followingdifferential equation:

(2)

where Qh = detention time = V/Q and Q = total flowrate = Qp + QR.

t Symbols and nomenclature are defined in Appendix D.

Figure 1: Schematic of a Completely Mixed System.

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