EPA/625/11-90/001
April 1991
User Documentation
POTW Expert vl.l
An Advisory System for Improving the Performance of
Wastewater Treatment Facilities
U.S. Environmental Protection Agency
Office of Research and Development
Center for Environmental Research Information
Cincinnati, OH 45268
Printed on Recycled Paper
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Notice ,
Both the software and user documentation have been reviewed in accordance with the U.S.
Environmental Protection Agency's peer review and administrative review policies and approved
for publication. Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
This computer software and user documentation is not intended to be a guidance or support
document for a specific regulatory program. Guidance documents are available from EPA and
must be consulted to address specific regulatory issues.
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POTW Expert
Version 1.1
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TABLE OF CONTENTS
ATTENTION
ACKNOWLEDGEMENTS v.
REGISTRATION FORM
TECHNICAL SUPPORT
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1 INTRODUCTION TO POTW EXPERT !
1.0 Introduction -
1.1 System Methodology j
1.1.1 Problem Definition !
1.1.2 Evaluation of Major Unit Processes 2
1.1.3 Identification and Prioritization of Performance 2
Factors
1.2 Technical Information 3
1.2.1 Hardware Requirements 3
1.2.2 Contents of the System 3
1.3 Installing POTW Expert 4
1.3.1 Make a Backup Copy of POTW Expert 4
1.3.2 Installation Routine 4
1.4 Running POTW Expert 5
1.4.1 Starting the Program 5
1.4.2 Introductory Screens 5
2 POTW EXPERT DATA ENTRY 7
2.0 Introduction -
2.1 POTW EXPERT Data Entry Features 7
2.1.1 Data Entry Forms 7
2.1.2 Single Answer Format 9
2.2 Windows and Menus o
2.3 Command Line 10
> POTW EXPERT DATA ENTRY FORMS 12
3.0 Introduction j2
3.1 The Data Entry Sequence 12
3.2 Input Tables 12
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CONTENTS, continued
SLUDGE HANDLING CONFIGURATION AND DATA ENTRY 158
4.0 Introduction 158
4.1 Creating a Sludge Handling Configuration 158
4.1.1 Starting a Configuration Screen 158
4.1.2 Adding Sludge Handling Units and Links 158
4.2 Sludge Handling Configuration Command Line 159
4.3 Leaving the Sludge Handling Configuration 161
4.4 Sludge Data Entry 161
4.5 Evaluation of the Sludge Handling Process 173
4.6 Explanation of Potential Projected Capacity 173
POTW EXPERT CONSULTATION AND REPORT GENERATION 175
5.0 Introduction 175
5.1 Data Integrity Check ' 175
5.2 Major Unit Processes Evaluation 175
5.2.1 Major Unit Processes Report 176
5.3 Evaluation of Performance-Limiting Factors 176
5.3.1 Observation Report 176
5.3.2 Identification and Prioritization of PLFs 177
5.3.3 Summary of Potential Performance-Limiting Factors Report 179
5.3.4 Final Performance-Limiting Factors Report 179
5.3.5 Data Entry Detail Report 179
5.4 Saving and Printing Reports 179
5.5 Files 180
5.3.1 Data Files 180
5.3.2 Report Files 181
APPENDIX A A-l
APPENDIX B B-l
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Attention
The POTW Expert system and user documentation are designed to supplement a full
Comprehensive Performance Evaluation (CPE) effort. The "expert" information contained in the
program's knowledge base was obtained from knowledge engineering sessions with the domain
experts and from:
» Handbook, Retrofitting POTWs, EPA/625/6-89/020
This document provides procedures for conducting POTW performance evaluations which include
the following:
on-site interviews conducted by a two-person evaluation team
data collection to gather both quantitative and qualitative information
an approach to identify reasons for non-compliance
an assessment of the suitability of existing facilities for improved performance
This product should be used in conjunction with the above handbook. It must be remembered
that this program can provide valuable assistance, but cannot replace the overall judgement and
experience of the evaluation. To obtain a copy of the Handbook, Retrofitting POTWs, fill in the
form below and send it to:
Center for Environmental Research information (CERI)
Technology Transfer
U.S. Environmental Protection Agency
P.O. Box 19963
Cincinnati, OH 45219-0963
Please send me a copy of Handbook, Retrofitting
POTWs, EPA/625/6-89/020
Name
Organization
Address
City
State
Zip
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Acknowledgements
This user documentation and expert system, POTW Expert were developed under EPA contract
No. 68-C8-0014. Many individuals contributed to the preparation and review of this expert system
and user documentation. Contract administration was provided by the Center for Environmental
Research Information, Cincinnati, Ohio.
System Developers:
Linda J. Berkman, B. Keith Law, Jennifer Jacobs, Andrew Hargens - Eastern Research Group,
Inc., Arlington, Massachusetts
Domain Experts:
Bob A. Hegg, Larry DeMers - Process Applications, Inc., Fort Collins, Colorado
Reviewers:
Susan Germain, Rick Alden, David Kyle - MA Dept. of Environmental Protection, Milford,
Massachusetts
John Esler - NYS Dept. of Environmental Conservation, Albany, New York
William Cosgrove - U.S EPA-Region 4, Athens, GA
Dick Pederson - Montana Dept. of Water Quality, Helena, MT
Technical Direction/Coordination:
Denis J. Lussier - U.S. EPA-CERI, Cincinnati, Ohio
Jack M. Teuschler - U.S. EPA-CERI, Cincinnati, Ohio
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SOFTWARE/USER REGISTRATION FORM
Software registration is the key to receiving the full benefits of EPA's Technology Transfer Support
Services. Please be sure to fill out the User Registration form and drop it in the mail. By returning this
card to EPA, you become entitled to participate in the services that are available with the POTW Expert
software package. ,
Periodically, EPA may make available upgrade/update versions of this program. If you are a registered
user, you will be notified of the Upgrades/Updates by EPA
Remember, Updates/Upgrades are automatically registered to you at the time of issuance only if you have
a completed User Registration Form on file with EPA To register, fill in the form below and send it to:
Center for Environmental Research Information (CERI)
Technology Transfer/POTW Expert Software Support
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
Please include me as a registered user of POTW Expert Version 1.1 This
will entitle me to automatic updates/upgrades and timely notification of
other news about this product.
Name
Title
Organization
Address
City
State
Zip
Phone
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TECHNICAL SUPPORT
EPA is committed to helping users get the most out of the POTW Expert software. You must return the User
Registration Form before you can benefit from EPA's Software Support Services. The following will be
helpful should you have to call for technical support.
Software/Hardware Information
Software version # (e.g., 1.1):
Computer Brand Name:
RAM (memory) kbytes:
Operating system name and version:
If possible, record the manufacturer and model number of these components:
Video Adapter Board:
Printer/Plotter:
Expansion RAM Board:
Before you call Software Support, please follow this Pre-Call Checklist. If you follow the Checklist, our
Software Technicians can help you more quickly and efficiently.
Step 1. Check to see if your computer meets the minimum hardware requirements necessary to use this
software as described in the POTW Expert Installation procedures. For detailed information
of the configuration of your hardware, contact the hardware manufacturer or the dealer where
you purchased the hardware.
Step 2. If your question is not answered by the user documentation, you can phone the EPA Expert
System Support Center, provided that you have completed the User Registration Form.
You can call the Expert System Software Support at the number below:
If possible, before you call, you should be sitting at you computer, with the computer on and the
software loaded.
Did the program work correctly any time before? If so, have you changed anything in the computer
environment (e.g., extended memory to expanded)?
» Can you reproduce the sequence of steps or the application that demonstrates the problem?
Did any error messages appear? If so, exactly what were they?
Telephone: (513) 569-7883
Hours: 8:30 a.m. to 5:30 p.m. (Central Time) Monday through Friday.
During non-business hours, your call will be answered by a voice-mail
system. Please leave your name, organization, telephone number, and
the time that you called.
If we can reproduce the specific problem on a hardware configuration supported by the software, we will
attempt to correct the problem. We may ask you to send us a copy of the data file that caused the error
(filename.SVR). If we cannot reproduce the problem on a supported machine, it may be because of a problem
caused by the hardware-software interface, and not the software itself. We then encourage you to phone your
hardware manufacturer for additional technical assistance.
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CHAPTER 1
INTRODUCTION TO THE POTW EXPERT
1.0 INTRODUCTION
POTW Expert is a PC-based software program modeled after EPA's Handbook, Retrofitting POTWs
(formerly, Handbook for Improving POTW Performance Using the Composite Correction Program
Approach^ POTW Expert assists POTW owners and operators, state and local regulators, and
consulting engineers to identify probable factors that hinder an existing facility's ability to achieve
optimum performance and/or capacity.
1.1 SYSTEM METHODOLOGY
1.1.1 Problem Definition
EPA's 1986 NEEDS Survey Report to Congress (an assessment of Publicly Owned Wastewater
Treatment Facilities in the United States) identified 10,131 of 15,438 operating POTWs as having
documented effluent quality or public health problems; the study estimated that $36.2 billion would
be required to address these problems. At the same time, federal funding to support POTW
improvements has been decreasing, as the federal government has asked states and local governments
to shoulder an increasing share of the financial responsibility for maintaining and upgrading POTW
performance. There is clear need among POTW owners/operators to optimize the performance of
existing facilities before embarking on major new design modification and construction projects.
Over the course of nearly a decade of EPA- and state-sponsored investigations, Process Applications,
Inc. (PAI) of Fort Collins, CO has developed a set of standardized procedures to analyze POTWs
and identify factors that contribute to degraded plant performance. Called a "Comprehensive
Performance Evaluation," or CPE, and described in the EPA Handbook, Retrofitting POTWs (EPA-
625/6-89-020), these procedures describe the approach to evaluating the capability of existing POTW
facilities to meet effluent permit requirements utilizing low-cost, non-construction-oriented options.
Significant components of a CPE are:
Evaluation of Major Unit Processes
« Identification and Prioritization of Performance-Limiting Factors
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1.1.2 Evaluation of Major Unit Processes
The goal of this step is to determine whether existing treatment processes are adequate to meet
effluent quality goals, given existing influent volumes and organic loadings. The evaluation consists
of an analysis of key major unit processes in the plant, which categorizes the plant into one of three
types:
Type 1 Capability of major unit processes do not limit plant performance.
Type 2 Capability of one or more major unit processes is marginal. Efforts to optimize all
aspects affecting the unit's capability are warranted prior to upgrade of the unit
process.
Type 3 One or more major unit processes is inadequate to satisfactorily treat existing influent
volumes or organic loads. Plant performance cannot improve significantly until the
limiting process(es) are upgraded.
Analysis of major unit process capability allows POTW operators, regulators, and consultants to assess
factors related to a facility's d.esign that contribute to a performance problem. The evaluation is
based on a unique scoring system, which facilitates categorization of process type. Much of the data
collected for the evaluation supplements subsequent identification of Performance-Limiting Factors.
For these reasons, the major unit process evaluation is one of the primary modules of POTW Expert.
1.1.3 Identification and Prioritization of Performance-Limiting Factors
A CPE identifies and prioritizes factors that can be correlated with plant performance problems.
Based on hundreds of completed plant analyses, a set of 66 factors related to plant administration,
maintenance, design, and operation are identified. These Performance-Limiting Factors (PLFs) are
structured as a series of questions that require the evaluator to judge the extent to which each PLF
may be related to the plant performance problem. Typically, an,analysis identifies 10 to 15 PLFs that
contribute to less than optimum performance.
To conduct a CPE, the evaluator obtains multiple data "inputs" through unit process assessments,
interviews with plant operators and administrators, and data collection, development, and
interpretation efforts. These activities are performed on site prior to utilizing POTW Expert. After
these data are obtained, the system allows the evaluator to proceed systematically through a sequence
of data entries until the prioritized list of factors is developed. The expertise, developed by Process
Applications, Inc., and incorporated into POTW Expert, includes the engineering and socio-economic
knowledge to distill the information provided by the evaluator into the most probable prioritized list
of PLFs for a particular facility. The final prioritization of factors is the evaluator's responsibility, and
is contingent upon the his or her judgement and interpretations.
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The end result is a list of PLFs, which defines those factors that must be addressed if plant
performance is to be improved. The real results are due to the identification and prioritization of
the unique combination of factors affecting a particular facility's performance.
h2 TECHNICAL INFORMATION
1.2.1 Hardware Requirements
The POTW Expert system requires an IBM Personal AT Computer (or more memory) or 100%
compatible with the following components:
A minimum of 640K bytes of RAM memory and 2Mb extended memory
1.2 megabyte disk drive
DOS version 3.0 or higher
A hard disk with at least 5 megabytes of free space
A printer (EPSON compatible) configured as system device PRN (optional)
If you have installed POTW Expert, but are unable to run the program, you may need to check your
computer's memory configuration. Although your computer may have the minimum memory
requirements of 640K bytes of memory and 2Mb extended memory, memory resident programs may
use some of this memory. If memory resident programs are installed and adequate memory is not
available for POTW Expert, an error message will appear on the screen when you attempt to run the
program. If this occurs, memory resident programs should be removed prior to beginning POTW
Expert (Edit your autoexec.bat file.) For more information on how to alter files, see the MS-DOS
manual that came with your computer.
To scan your drive and report the status of the disk and available memory you can run the MS-DOS
command Chkdsk (check disk). This command will list the total amount of memory and available
memory (e.g., free). In addition, the POTW Expert system disk includes an optional program that
can be run to check the amount of available memory. To start the memory check program, insert
the POTW Expert system disk into drive A and type the following:
armapmem
and press the Enter key.
1.2.2 Contents of the System
POTW Expert system includes one (1) double-sided, high density, 1.2Mb, 5 1/4" diskette and user
documentation.
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1.3 INSTALLING POTW Expert
1.3.1 Make a Backup Copy of POTW Expert
Make a backup copy of the POTW Expert system diskettes prior to installation. For information
about how to copy a diskette using the DISKCOPY or COPY commands, see the MS-DOS manual
that came with your computer.
1.3.2 Installation Routine
The POTW Expert installation program reads all files from the POTW Expert system disk in the
floppy drive (i.e., drive A or drive B). If your computer has only one drive slot, this is the A drive.
If your computer has more than one drive slot, generally the top drive or the left-hand drive is the
A drive. If there is any question about which is your computer's A drive, consult the MS-DOS
manual that came with your machine.
The POTW Expert installation program automatically creates a directory called POTWEX on your
computer's hard disk. All program files, and conclusion files are stored in the POTWEX directory
on the hard disk.
POTW Expert may be installed to on any default drive (e.g., c, d, e). For the purpose of this
installation procedure we will assume that the default drive is drive c. When you are ready to install
POTW Expert:
1) Place the POTW Expert system disk in your computer's floppy drive.
2) At the C: prompt (shown as C> on the screen), type A:INSTALL or B:INSTALL. Press
the ENTER key.
(NOTE: If you already have a POTW Expert directory on your computer's hard disk, you will
receive the message Unable to create directory. This is not a problem. It simply means
that the installation routine will reuse the existing directory instead of creating a new one.
Files on the hard disk are replaced by the version of POTW Expert on the system floppy
disk.)
3) Follow the instructions on the screen. The name of each file on the POTW Expert
system disk should appear on the screen as it is copied.
4) Remove the POTW Expert system disk from the floppy drive.
After the installation program is completed, the C: prompt will reappear on the screen and you are
ready to run POTW Expert.
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1.4 RUNNING POTW Expert
1.4.1 Starting the Program
If you have just installed POTW Expert, you are automatically in the C:\POTWEX directory In this
case, type POTWEX and press ENTER to start running POTW Expert.
If you have been using another program or just turned the machine on, follow these procedures:
If the screen shows A> or B> rather than C>, type C: and then press ENTER. This
command assures that you are working on the hard drive. If the screen shows a O
prompt, proceed to the next step.
ShOWS C:\POTWEX>' that «, a C: prompt with the directory listed as
POTWEX, proceed to the next step. Otherwise, type CD\ and press ENTER This
command assures that you are in the POTW Expert subdirectory.
Type POTWEX and press ENTER to begin the program.
For more information on directories and entering DOS commands, see the MS-DOS user's manual
that came with your computer. momuu
1 .4.2 Introductory Screens
Once started, the POTW Expert program automatically presents a sequence of three introductory
screens. The sequence includes: y
1) The POTW Expert title screen, which lists the development information,
2) A screen presenting a brief system description.
3) A screen from which the user elects to Start New Session, Load Saved Data, or Continue
to edit the current data set (see Figure 1-1).
After viewing the first two screens, press ENTER to select Continue in the lower right and proceed
to the next screen. The third screen (Figure 1-1) includes a three-item menu in the lower right
below1" 6 °Ptl°nS (SdeCt USfag ^ arr°W kCyS and prCSS ENTER to execute) are described
Start New Session - Clears all existing data and begins a new consultation.
Load Saved Data - Clears all existing data and displays a list of saved data files that can
be selected and loaded for editing and/or reanalysis.
" Proceeds directly to the first data entry screen, preserving the existing data set
1 his feature allows a user who has exited a data entry form (see Section 2.3) to return to
the beginning of the program to review and edit the data sequence that has just been
input. J
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POTW Expert third
Introductory screen:
details the three
procedure options
Question Window:
explains the current
question or the
required user action
POTW EXPERT
To START a new sanion select START NET SESSION.
To LOAD data from a prerioua 'session select LOAD SAVED DATA.
To CONTINUE with existing session select CONTINUE.
NOTE: LOADING DATA FROlf A PREVIOUS SESSION
MAY TAKE UP TO SEVERAL MINUTES ...
Select the appropriate action.
Start New Session
load Sand Data
Continue
Response Menu:
window for choosing
a response using
arrow keys to
highlight and ENTER
Figure 1-1. The third POTW Expert introductory screen from which the user elects to begin
a Start New Session, Load Saved Data, or Continue.
NOTE; Selecting F7: Quit and End Session and Restart from the command line of a data entry
form will return the program to the beginning to allow for data to be reviewed and edited.
When one of the options described above is chosen, the first POTW Expert data entry form,
GENERAL INFORMATION, appears.
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CHAPTER 2
POTW EXPERT DATA ENTRY
2.0 INTRODUCTION
This chapter describes the POTW Expert data entry system. After completing the installation and
start-up routines described in Chapter 1, the system is prepared to accept user inputs. POTW Expert
integrates user-friendly windows, menus, and function keys in a series of uncomplicated data entry
screens. All user command options and other necessary information are constantly displayed on the
screen. In addition to being easy to use, the format and the sequence of data entry screens organizes
data by topic. The POTW Expert data entry system is described in more detail below.
2.1 POTW EXPERT DATA ENTRY FEATURES
POTW Expert has two data entry mechanisms, Data Entry Forms and the Single Answer Format.
Both response formats accept numeric and multiple choice input and both are composed of menus
and windows. The system first requests information, by category, in the Data Entry Forms. If
information necessary to complete an analysis is not entered, each question is asked a second time
in a Single Answer Format screen.
2.1.1 Data Entry Forms
Data Entry Forms appear when a series of data must be entered. Each Data Entry Form requests
a group of information about a specific aspect of the POTW Expert system. For example, all the
data about the rectangular secondary clarifier is one such information group. The tables in Chapter
3 list all the Data Entry Forms, the questions each include, and all accepted answers.
A Data Entry Form, as seen in Figure 2-1, consists of four information windows that are arranged
to allow systematic data input and editing. The text and menus within these windows, in conjunction
with the command line described below, work together to create a straightforward data entry system.
Basically, data is requested on the left side of the screen and entered on the right. Field descriptors
(data cells) are listed in the column in the upper left window and data is entered in the data entry
fields in the upper right window. Data is entered by either typing it in the cells in the Response
Window (the right column) or selecting it from the response menu, called by pressing F10: Menu (see
Section 2.3). When all of the questions in the Data Entry Form have been answered, pressing F5:
Next Screen takes you to the next screen.
(NOTE; If there are more data cells in a data entry form than will fit on the screen at one time, a
small scroll arrow indicates that more questions remain to be scrolled onto the screen.)
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Two windows across the bottom of the page provide response bounds and an expanded explanation
of the required user response or action. The function of each window is described below.
In the upper left, the Question List Window lists the field descriptors or data cells as a series
of abbreviated questions.
In the upper right, the Response Window provides data input lines that correspond to the
question lines in the Question List Window.
Directly below the Question List Window and the Response Window, the Bounds Window
provides the data limits (numeric boundaries) or multiple choice options for the current
highlighted question. The system requires numeric bounds to screen out inconsistent or
unacceptable data.
Below the Bounds Window, across the bottom of the screen, the Expanded Question
Window gives the complete form of the current highlighted question or required user action.
Screen Header
Question List Window:
lists a scries of ^
abbreviated questions
Bounds Window:
lists the accepted
multile-choice responses
or numeric bounds >
Command Line:
lists the active
(unction keys and
the commands they
execute
General Information
Name ol POTf
Name of Sraluator
Tjfo of Secondary Treatment Process
Population Served
Tea»8ter POTT
S. a-ejel
25050
Choices ore: Suspended Growth; Rxed Film; Stabilization Pond
Select the type of secondary treatment
process used in this plant (See Help}
Fl: Help F3: Save F5: Next Screen F7: Quit FB: Clear Reid F10: Menu
Response Window:
contains fields in
which to enter
responses
Expanded Question Window:
explains the current question
in greater detail
Figure 2-1. General Information data entry screen, simulating the cursor on the third question,
Type of Secondary Treatment Process. Note the question-specific information in the
Bounds Window and the Expanded Question Window.
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2.1.2 Single Answer Format
Some critical information is necessary for POTW Expert to complete a successful evaluation If key
data are omitted from the Data Entry Form, the system will present questions a second time
individually, using the Single Answer Format screens. This screen displays only the current question
and answer cell. The expanded version of the current question is displayed in the larger window at
the top of the screen, and instructions are displayed in the lower window. The-response options
numeric bounds, and multiple-choice options appear in a third "pop-up" window. Figure 2-2 shows
an example of a Single Answer Format.
Variable Label
Clarification
or Help Text
Acceptable value limits:
end points are in the
acceptable range . >
Expanded Question Window:
gives the required user >
response or action
BODS Effluent Permit Requirement
Because of national implications of water quality
rsquireznenta...
Bounds are 0-10,000.000
Whot is the permitrequired BODS concentration
of the final clorifer in mg/l?
Figure 2-2. Single answer format data entry screen. Note the clarification or help text which
appears in the center of the screen.
2.2 WINDOWS AND MENUS
Both of POTW Expert's data entry formats use windows and menus to facilitate data entry The
specific window functions are discussed in Section 2.1. This section explains how to use these
features.
Windows are panels or subsections of the screen that contain a menu or text explanation. They often
appear layered on top of an underlying image. A window that appears automatically or when an
assigned key is pressed is called a "pop-up" window. Within a Data Entry Form, the screen is divided
into tour windows that coincide on the screen while data is being input (see Figure 2-1). A number
ot pop-up windows can be called by pressing assigned function keys. For example, pressin* F10:
Menu, produces a "pop-up" window containing the Response Menu of possible user inputs (see
figure 2-3). When a response is selected from the menu, the window disappears. The active
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function keys that call pop-up windows are listed in the command line at the bottom of each data
entry screen. Section 2.3 describes of the active function keys and their associated commands.
A menu is a list of choices that appears within a window. Menus are used throughout POTW Expert
to select the major program commands and answer options. Some menus appear automatically and
some are called by pressing a function key. The Load Saved Data Menu, that appears at the
beginning of the program, is an example of a menu that appears automatically. Menus that are
activated by the user appear on the screen when an assigned key (usually a function key) is pressed.
An example of a user-triggered menu is the Response Menu, called by pressing the F10: Menu
function key within the data entry form. Arrow keys are used to move a highlighted (inverse video)
cursor block through the menu choices. When the desired choice has been highlighted, pressing
ENTER executes the command or selects that option.
2.3 COMMAND LINE
The command line, which appears at the bottom of each data entry form (Figures 2-1 and 2-3), lists
the keys that execute commands necessary to enter data and move throughout POTW Expert.
Pressing one of these keys executes the chosen command or brings a menu to the screen. The active
function keys vary for the systems different types of data entry forms. A complete list of the active
POTW Expert function keys and descriptions of their assigned commands are listed below.
F1: Help
F3: Save/Output
PS: Next Screen
F6: Data
F7: Quit
Brings an expanded description of the current question to the screen (see
Figure 2-3).
a) Calls the Save Menu to a pop-up window within the Data Entry Form.
Menu choices allow an Existing file to be loaded from the A:, B:, or C: drive
or a New file to be created.
b) Calls the Output Menu that includes save and print features from within
the Summary Report Screen. Report files can be saved to a file in ASCII
format for editing and printing.
(NOTE: The Output Menu replaces the Save Menu in the command line
after the analysis has been completed and the reports compiled.)
Proceeds directly to the next data entry screen following confirmation.
With in the Summary Report Form, displays the full list of system variables
and user inputs on the screen. This list can be saved to a file in ASCII format
for editing and printing.
Calls the Exit Menu that includes Exit System and Restart options. There is
no save feature within this menu.
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Exit System: Leaves the system following confirmation without saving data.
Restart: Returns to the beginning of the program to the Load Saved Data
screen to review and edit data.
F8: Clear Field
F10: Menu
ENTER: Accept
ESC: Escape
Clears an existing response in the current data entry field (the highlighted
response line on the right side of the data entry screen). ° *
Calls a window containing a multiple choice Response Menu or numeric input
bounds. Choices are selected using arrow keys and entered bv pressm*
ENTER. ' *
Once a desired response has been typed in the data entry field or hicrhli
Fixed Him Facilities
Activated Bio-Filter (ABF)
Botattog Biological Contactors (RBC)
Trickling Filters (rock or plastic media)
Stabilization Ponds
Facultative
Aerated
Select the type of secondary treatment
process used in this plant (See Help)
Suspended Growth
fixed Film
Stabilization Pond
ESC: Coneel ENTER; Accept F8: Clear Reid t /I Scroll
Response Menu:
pop-up window
^_ for choosing
response
^~ Command Line:
lists the active
function keys and
the commands they
execute
Figure 2-3.
The detailed Fl: Help information screen that can be called for every data entry field
Also, note the F10: Menu response menu in the lower right corner, from which
responses can be selected and entered.
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CHAPTER 3
POTW EXPERT DATA ENTRY FORMS
3.0 INTRODUCTION
As described in Chapter 2, POTW Expert accepts data on specific plant characteristics and on the
volume and characteristics of plant influent through data entry forms. This chapter includes lists
of all possible system questions and acceptable answers. These sections may be useful for
compiling data from the Retrofitting POTWs Handbook field evaluation forms and field notes
before running the system.
3.1 THE DATA ENTRY SEQUENCE
There is tremendous potential for variation in the particular equipment employed and the
specifics of process configuration between POTWs. POTW Expert has been developed to be
useful across a broad spectrum of the POTW community, and therefore includes the capability to
analyze the performance capability of a large number of combinations of specific unit processes.
The sequence of data entry forms POTW Expert displays reflects the user's responses to
questions regarding the design and equipment characteristics for the POTW under evaluation.
Figures 3-1, 3-2, and 3-3 show the data entry relationships that are possible for Fixed Film,
Suspended Growth, and Stabilization Pond Facilities.
3.2 INPUT TABLES
This Chapter includes complete versions of all POTW Expert questions and response options.
The sections contain the information the system displays on the screen within each POTW Expert
Data Entry Form. See Chapter 2 for an expanded description of Data Entry Forms. Below is a
list of chapter contents. Facility types are abbreviated as FF for Fixed Film, SG for Suspended
Growth, and SP for Stabilization Pond. Use these tables for compiling data from the field
evaluation forms and field notes before running the system.
DATA INPUT SECTIONS
General Information
FF - Data Branching Options
SG - Data Branching Options
SP - Data Branching Options
Primary Clarifier
Plant Hydraulic and Organic Loading
Wastewater Recirculation - Trickling Filter, ABF
Wastewater Recirculation - Trickling Filter, RBC
PAGE
17
21
24
27
29
32
37
40
-12-
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DATA INPUT SECTIONS, cont. PAGE
FF - Trickling Filter 45
FF - Rotating Biological Contactor 47
FF - Activated Bio-Filter, Diffused 50
FF - Activated Bio-Filter, Mechanical 55
FF - Trickling Filter/RBC - Secondary Clarifier, Rectangular 60
FF - Trickling Filter/RBC - Secondary Clarifier, Circular 67
FF - Activated Bio-Filter - Secondary Clarifier, Rectangular 74
FF - Activated Bio-Filter - Secondary Clarifier, Circular 84
SG - Aeration Basin, Diffused 92
SG - Aeration Basin, Mechanical 97
SG - Secondary Clarifier, Rectangular 101
SG - Secondary Clarifier, Circular HO
Aerated Pond Facility 118
Facultative Pond Facility 123
Stabilization Ponds 126
Industry Contributors 132
Performance Limiting Factors 136
Process Control Test 141
Follow-Up Questions for Process Control Testing 153
All system questions, help explanations, and answer options are presented in the tables that begin
on page 17. These items are organized in two columns, Screen Text Questions on the left and
Answer Options on the right. The left column includes three types of information:
Screen Text Questions -- The abbreviated form of each POTW Expert question,
numbered and bolded, is listed as the item title. This is the same text that appears in the
Data Entry Form Question List Window.
Help - A detailed version of the current question is in the normal font. The system
displays this information when F1: Help is pressed within the Data Entry Form. Users
may wish to reference this detailed explanation.
Expanded Question ~ The version of the question that appears in the Expanded
Question Window (see Figure 2-1) appears in italics. This question is a more direct
explanation of the required user response or action.
The acceptable answers/inputs corresponding to each question in the left column are specified in
the right Answer Options column. Listed are the inputs, either a list of multiple choice options
or, for numeric answers, lower and upper bounds, that can be entered to the POTW Expert data
entry forms. For numeric answers, the bounds serve to screen user inputs, providing a data
integrity check. ft- &
-13-
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GENERAL
INFORMATION
PLANT BRANCHING
OPTIONS
FIGURE 3-1:
FIXED FILM FACILITY
POTW Expert Flow Diagram
OPTIONAL
PLANT HYDRAULICS
AND ORGANIC
LOADING
WASTEWATER
RECIRCULAT10N
(
OPTIONAL
INDUSTRY
CONTRIBUTORS
CONFIGURATION
SLUDGE
KEY
k.
>
J
( >
r \
PERFORMANCE I
UMTING 1
MUP
REPORT
C PERFORMANCE 1
LIMITING 1
FACTORS 1
J
\
f
r^\
OBSERV.
REPORT
IDENTIFY
POTENTIAL ]
PLFS
PLF
REPORT
-14-
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PLANT HYDRAULICS
AND ORGANIC
LOADING
FIGURE 3-2:
SUSPENDED GROWTH FACILITY
POTW Expert Flow Diagram
)
\ ' *»
V >
^
MANCE 1
ING I
MUP
REPORT
OBSERV.
REPORT
PLF
REPORT
-15-
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[GENERAL I
INFORMATION I
FIGURE 3-3:
STABILIZATION POND FACILITY
POTW Expert Flow Diagram
PLANT BRANCHING
OPTIONS
PLANT HYDRAULICS
AND ORGANIC
LOADING
OPTIONAL
c
INDUSTRY
CONTRIBUTORS
KEY
CCNO.WOM
UTOKT
[PERFORMANCE I
UMTING I
FACTORS I
\f
MUP
REPORT
IDENTIFY
[ POTENTIAL ]
PLFS
OBSERV.
REPORT
-16-
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POTW EXPERT DATA ENTRY
GENERAL INFORMATION
SCREEN Tiber QUESTIONS
ANSVirefl OPTIONS
1. Name of POTW.
What is the name of this treatment facility?
Plant name?
POTW name
2. Name of Evaluator.
What is the name of the evaluator?
What is your name?
Your name
3. Type of Secondary Treatment Process.
The types of secondary treatment processes are:
Suspended Growth Facilities -
Conventional Activated Sludge
Extended Aeration (including oxidation ditches)
Contact Stabilization
Fixed Film Facilities -
Activated Bio-filters (ABF)
Rotating Biological Contactors (RBC)
Trickling Filters (rock, plastic, or redwood
media)
Stabilization Ponds -
Facultative
Aerated
Select the type of secondary treatment process used in this
plant (see Help).
Suspended growth
Fixed film
Stabilization pond
-17-
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SCREEN TEXT QUESTIONS {
ANSWER OPTIONS
4. Population Served.
What is the population that contributes waste to the
treatment facility? '
What is the population that contributes waste to the treatment
facility?
Lower bound: 0
Upper bound: 500,000
5. Plant Location.
Enter the state in which this plant is located. Use a valid,
two letter abbreviation. In the following list, abbreviations
are capitalized.
Alabama
California
ELorida
ILlinois
Kentucky
Massachusetts
Missouri
New Hampshire
No. Carolina
ORegon
South Dakota
VermonT
Wisconsin
Enter the state in which this plant is located. The state must
be a valid, capitalized, two letter abbreviation.
Enter state abbreviation
AlasKa
Colorado
GeorgiA
INdiana
LouisiAna
Michigan
MonTana
New Jersey
North Dakota
PennsylvAnia
TeXas
VirginiA
WYoming
Arizona
ConnecTicut
Hawaii
lowA
MainE
MiNnesota
NeVada
New Mexico
OHio
Rhode Island
TeNnessee
WAshington
ARkansas
DElaware
IDaho
KanSas
MarylanD
Mississippi
NEbraska
New York
OKlahoma
So. Carolina
UTah
W. Virginia
-18-
-------
ANSWER OPTIONS
6. Superintendent Salary. » Lower bound: 0
Upper bound: 500,000
Job descriptions for three key process control positions will
be described. Although these descriptions may not precisely
describe the personnel at this particular plant, enter the
salary of that person whose responsibilities most closely
corresponds to the Superintendent's job description.
Superintendent - The person who has broad responsibility for
all the plant function including operations, maintenance,
laboratory, administration, and minor plant modifications.
Enter the annual salary for the plant's SUPERINTENDENT.
If unknown, enter 0.
7. Operations Supervisor Salary. Lower bound: 0
Upper bound: 50,000
Job descriptions for three key process control positions will
be described. Although these descriptions may not precisely
describe the personnel at this particular plant> enter the
salary of that person whose responsibilities most closely
correspond to the Supei visor's job description.
Operations Supervisor - The person who has the
responsibility for all operational activities at the plant
including operations, staffing functions, and supervising staff
responsible for process control decisions.
Enter the annual salary for the plant's OPERATIONS
SUPERVISOR. If unknown, enter 0.
-19-
-------
SCREEN TEXT ^UESTJONS
ANSWER OPTIONS
8. Key Operator Salary.
Job descriptions for three key process control positions will
be described. Although these descriptions may not precisely
describe the personnel at this particular plant, enter the
salary of that person whose responsibilities most closely
corresponds to the Key Operator's job description.
Key Operator - The person who has responsibility for process
control decisions and adjustments at the plant.
Enter the annual salary for the plant's KEY OPERA TOR. If
unknown, enter 0.
Lower bound:
Upper bound:
0
45,000
-20-
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POTW EXPERT DATA ENTRY
FIXED FILM
DATA BRANCHING OPTIONS
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Primary Clarifier(s).
Primary clarification is the treatment process during which
pollutants are removed from the wastewater by gravity settling
and by flotation.
Are primary clarification facilities provided?
Yes
No
2. Type of Fixed Film Process.
Which of the following fixed film secondary treatment
processes does this POTW use?
Activated Bio-Filter (ABF) equipped with a Diffused
Aeration System -
air is introduced to the wastewater through multiple air
inlets in the basin
Activated Bio-Filter (ABF) equipped with a Surface
Mechanical Aeration System -
air is introduced to the wastewater through agitation of
the water surface by a mechanical mixer
Rotating Biological Contactors (RBC)
Trickling Filter
Select the most appropriate process.
ABF - Diffused Aeration
ABF - Surface Mechanical
Aeration
RBC
Trickling Filter
-21-
-------
SCREEN TEXT QUESTIONS
~ - -AHS^ltf OJ»TfdNS^ ',
'v,rt
-------
QUESTIONS
ANSWER OPTIONS
6. Number of Industry Contributors.
Industrial wastes may be adversely affecting the existing
capabilities of the POTW. If it is possible to identify one or
more industries that contribute industrial wastes to the
POTW, then enter the number of contributing industries.
For each industry that is entered into the system, you will be
asked to provide the name, average daily flow, BODS
concentration, and TSS concentration data.
If more than three industries exist, you may choose to
combine several industries so that all can be included. If a
specific industrial waste problem cannot be identified, enter 0.
Enter the number of industries that may be contributing
significant industrial wastes to the POTW. If industrial wastes
are not a problem or they cannot be identified, enter a 0 in the
data entry field.
Lower bound:
Upper bound:
0
3
7. Septic Contributors.
Septic waste may be adversely affecting the existing
capabilities of the POTW. If septic waste is entered into the
system, you will be asked to provide average daily flow, BOD5
concentration, and TSS concentration data.
Is septic waste entered into this POTW?
Yes
No
-23-
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POTW EXPERT DATA ENTRY SUSPENDED GROWTH
DATA BRANCHING OPTIONS
SCREEN TEXT QUESTIONS^ '-; { ANSWER OPTfONS
1. Primary Clarifier(s). Yes
No
Primary clarification is the treatment process during which
pollutants are removed from the wastewater by gravity settling
and by flotation.
Are primary clarification facilities provided?
2. Type of Suspended Growth Process. Conventional Activated
Sludge
Which of the following processes does this POTW use? Extended Aeration
Contact Stabilization
Conventional Activated Sludge -
includes tapered aeration, step flow, plug flow, and
complete mix
Extended Aeration -
includes oxidation ditch
Contact Stabilization
Select the most appropriate process.
-24-
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SCREEN TEXT QUESTIONS
ANSWEH OPTIONS
3. Type of Aeration.
What type of aeration system does this POTW use?
A Diffused Aeration System -
air is introduced to the wastewater through multiple air
inlets in the basin
A Surface Mechanical Aeration System -
air is introduced through agitation of the water surface
by a mechanical mixer
Select the type of aeration system that most closely matches the
current system.
Diffused Aeration System
Surface Mechanical
Aeration
4. Secondary Clarifier Shape (see Help).
Often a plant will have more than one secondary clarifier. If
this is the case, and there are both circular and rectangular
clarifiers, choose the shape of the clarifier(s) that receive the
greatest flow. For example, if a plant has an old rectangular
clarifier and new circular clarifiers, which carry more than 50%
of the flow, choose circular as the shape. It is noted that
choosing rectangular will give the most conservative results.
Select the appropriate shape for the secondary clarifier.
Circular
Rectangular
5. Volume of Flow Equalization Basin, gal.
The primary objective of flow equalization basins for municipal
wastewater plants is to dampen the diurnal flow variations, as
well as variations caused by inflow/infiltration, on the
downstream treatment processes. The volume of the basin
relative to incoming flow is utilized to characterize a flow
equalization basin's dampening capability.
If the plant does not have a flow equalization basin, enter 0.
What is the volume of the flow equalization basin, in gallons?
If basin does not exist, enter 0.
Lower bound:
Upper bound:
0
20,000,000
-25-
-------
SCREEN TEXT QUESTIONS . ANSWER OPTIONS
6. Number of Industry Contributors. Lower bound: 0
Upper bound: 3
Industrial wastes may be adversely affecting the existing
capabilities of the POTW. If it is possible to identify one or
more industries that contribute industrial wastes to the
POTW, then enter the number of contributing industries.
For each industry that is entered into the system, you will be
asked to provide the name, average daily flow, BOD5
concentration, and TSS concentration data.
If more than three industries exist, you may choose to
combine several industries so that all can be included. If a
specific industrial waste problem cannot be identified, enter 0.
Enter the number of industries that may be contributing
significant industrial wastes to the POTW. If industrial wastes
are not a problem or they cannot be identified, enter 0.
7. Septic Contributors. Yes
No
Septic waste may be adversely affecting the existing
capabilities of the POTW. If septic waste is entered into the
system, you will be asked to provide average daily flow, BOD5
concentration, and TSS concentration data.
Is septic waste entered into this POTW?
-26-
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POTW EXPERT DATA ENTRY
STABILIZATION POND
DATA BRANCHING OPTIONS
ANSWER OPTIONS
1. Type of Stabilization Pond Process.
Which of the following stabilization pond treatment systems
does this POTW use?
A Facultative Pond system, or
A Aerated Pond System - air is introduced through
agitation of the water surface by a mechanical mixer or
through multiple air inlets in the pond.
Select the most appropriate stabilization pond treatment system.
Facultative Pond System
Aerated Pond System
2. Number of Industry Contributors.
Industrial wastes may be adversely affecting the existing
capabilities of the POTW. If it is possible to identify one or
more industries that contribute industrial wastes to the POTW
then enter the number of contributing industries.
For each industry that is entered into the system, you will be
asked to provide the name, average daily flow, BOD5
concentration and TSS concentration data.
If more than three industries exist, you may choose to
combine several industries so that all can be included. If a
specific industrial waste problem cannot be identified, enter 0.
Enter the number of industries that may be contributing
significant industrial wastes to the POTW. If industrial wastes
are not a problem or they cannot be identified then enter a 0 in
the data entry field.
Lower bound:
Upper bound:
0
3
-27-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
3. Septic Contributors.
Septic waste may be adversely affecting the existing
capabilities of the POTW. If septic waste is entered into the
system, you will be asked to provide average daily flow, BOD5
concentration, and TSS concentration data.
Is septic waste entered into this POTW?
Yes
No
-28-
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POTW EXPERT DATA ENTRY PRIMARY CURIFIER
SCRPE^I TEXT QUESTIONS.: ANSWER OPTIONS
Lower bound: 0
1. Surface Area of Primary Clarifier(s), sq ft 'Upper bound: 35,000
Enter the total surface area of the primary clarifier(s), in
square feet
Enter the total surface area of the primary darifier(s), in square
feet.
2. BODS Cone, from Primary Clarifier(s), mg/I. Lower bound: 0
Upper bound: 1,000
Enter the annual average concentration of BOD5 in the
effluent from the primary clarifier(s), in mg/1. If the primary
clarifier effluent concentration is not available, then POTW
Expert will calculate a removal rate based on the following
schedule:
Surface Overflow Rate % Removal
(gallons per day of BOD5
per square feet)
0 - 1000 gpd/sq ft 30
1000 - 1500 gpd/sq ft 20
1500 - 2000 gpd/sq ft 10
> 2000 gpd/sq ft no removal
What is the average effluent BOD5 concentration from the
primary clarifier(s) for the previous twelve months, in mg/l?
-29-
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SCREEN TEXT QUESTIONS H ANSWER OPTIONS
3. TSS Cone, from Primary Clarifier(s), mg/1. Lower bound: 0
Upper bound: 1,000
Enter the annual average concentration of TSS in the effluent
from the primary clarifier(s), in mg/1. If the primary clarifier
effluent concentration is not available, then POTW Expert will
calculate a removal rate based on the following schedule:
Surface Overflow Rate % Removal
(gallons per day of TSS
per square feet)
0 - 1000 gpd/sq ft 65
1000 - 1500 gpd/sq ft 45
1500 - 2000 gpd/sq ft 30
> 2000 gpd/sq ft no removal
What is the average effluent TSS concentration from the primary
clarifier(s) for the previous twelve months, in mg/l?
-30-
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SCREEN tear QUESTIONS
' '
ANSWER OPTIONS
4. Sludge Vol. from Primary Clarifiers(s), gpd.
Sludge is typically pumped from the primary clarifier(s) to
digestion or thickening facilities. Often a positive
displacement pump is used for this purpose. Monitoring the
strokes of these pumps can provide information on the volume
of sludge pumped. If the volume of sludge pumped from the
primary clarifier is not available, then enter 0 and POTW
Expert will calculate a volume based on a typical underflow
concentration and a typical suspended solids removal from a
primary clarifier based on the following schedule:
Surface Overflow Rate
(gallons per day
per square feet)
0 - 1000 gpd/sq ft
1000 -1500 gpd/sq ft
1500 - 2000 gpd/sq ft
> 2000 gpd/sq ft
% Removal
ofTSS
65
45
30
no removal
Enter the daity average volume of sludge pumped from the
primary clarifier(s) for the previous twelve months, in gallons per
day. If unknown, enter 0.
Lower bound:
Upper bound:
0
5,000,000
5. Sludge Cone, from Primary Clarifier(s).
If no thickening unit processes are available, sludge is typically
pumped as thick as possible from the primary clarifier. This
must be balanced with minimizing decomposition and
associated gasification and scum formation.
If the concentration of sludge pumped from the primary
clarifier(s) is not available, then enter 0 and POTW Expert
will calculate a volume based on a typical underflow
concentration.
Enter the daify average sludge concentration pumped from the
primary clanfter(s) for the previous twelve months, in % by
weight. If unknown, enter 0.
Lower bound:
Upper bound:
0
15
-31-
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POTW EXPERT DATA ENTRY
PLANT HYDRAULICS AND ORGANIC LOADING
SCREEN TEXT OUESTIONS
ANSWER OPTIONS
1. Maximum Monthly Average Daily Flow, gpd.
Several flow rates are used for evaluating a wastewater
treatment plant. The maximum monthly average daily flow is
determined as follows: for each of the past 12 months
calculate the monthly average, where monthly average = (total
of daily flows for a given month)/(# of days in a month).
Then select the highest monthly average flow from the last
twelve months of data.
What was the maximum, monthly average daily flow to the
facility, in gallons per day, for the previous twelve months?
Lower Bound: 0
Upper Bound: 30,000,000
2. Average Daily Flow, gpd.
The average daily flow rate is determined by totaling the daily
flows to the plant during the past year and dividing by 365.
What is the average daily flow to the facility, in gallons per day,
for the previous twelve months?
Lower Bound: 0
Upper Bound: 20,000,000
3. Minimum Monthly Average Daily Flow, gpd.
Several flow rates are used for evaluating a wastewater
treatment plant. The minimum monthly average daily flow is
determined as follows: for each of the past 12 months
calculate the monthly average, where monthly average = (total
of daily flows for a given month)/(# of days in a month).
Then select the lowest monthly average flow from the last
twelve months of data.
What was the minimum monthly average daily flow to the
facility, in gallons per day, for the previous twelve months?
Lower Bound: 0
Upper Bound: 20,000,000
-32-
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ANSWER OPTIONS
4. Short-Term Seasonal flow Variations, gpd (see Help).
Does this POTW periodically experience large seasonal flow
variations (e.g., Christmas, holiday peaks) of less than one
month's duration? When large seasonal flow variations last
less than one month, the peak monthly average may not fully
capture the significance of the event or its impact on the
POTW's performance. If such a situation does exist, enter the
peak weekly average daily flow (PWA), in gallons per day, for
the past year, where PWA is determined as follows: weekly
average = (total of daily flows for a given week)/?.
Then select the highest weekly average, where peak weekly
average = maximum of weekly averages for the past 52 weeks.
If large seasonal flow variations are not a problem, enter 0.
If the plant experiences large short-term seasonal flow variations,
enter the peak weekly average daily wastewater flow, in gallons
per day. If large seasonal flows are not a problem, enter 0.
* Lower Bound:
Upper Bound:
0
35,000,000
5. Influent BODS Concentration, mg/1.
Enter the influent daily average BOD5 concentration for the
most recerit twelve months. (Exclude side streams from the
influent BOD5.)
What is the daity average BOD5 concentration for the previous
twelve months, in mgll? If unknown, enter 0.
« Lower Bound:
Upper Bound:
0
1,000
-33-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
6. Influent TSS Concentration, mg/1.
Enter the influent daily TSS concentration for the most recent
twelve months (exclude sidestreams from the influent TSS). If
TSS concentration is unknown, enter 0. POTW Expert will
assume a TSS concentration based on organic loading.
What is the TSS concentration for the previous twelve months,
intngll? If unknown, enter 0.
Lower Bound: 0
Upper Bound: 1,000
7. Effluent BODS Permit Requirement, mg/1.
The federal government initiated a national program for
permitting discharges from wastewater treatment facilities.
These permits control maximum effluent BOD5 and TSS
concentrations. Nationally, a monthly average BOD5
concentration of 30 mg/1 is allowed for secondary treatment
facilities. If this requirement is not sufficient to attain
acceptable water quality, the water quality standards of the
receiving waters will dictate a more stringent level of
treatment Also, the states have the right to set more
stringent effluent quality requirements.
Enter the monthly average effluent BOD5 concentration, in
mg/1, required by the facility's discharge permit. If seasonal
requirements exist, enter the most stringent effluent
concentration.
What is the monthly average effluent BOD5 concentration
allowed by the facility's discharge permit, in mg/l?
Lower Bound:
Upper Bound:
0
200
-34-
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SCREEN TEXT QUESTIONS
!"'
ANSWER OPTIONS
8. Effluent TSS Permit Requirement, mg/I.
The federal government initiated a national program for
permitting discharges from wastewater treatment facilities.
These permits control maximum effluent BODS and TSS
concentrations. Nationally, a monthly average TSS
concentration of 30 mg/l is allowed for secondary treatment
facilities. If this requirement is not sufficient to attain
acceptable water quality, the water quality standards of the
receiving waters will dictate a more stringent level of
treatment. Also, the states have the right to set more
stringent effluent quality requirements.
Enter the monthly average effluent TSS concentration, in
mg/1, required by the facility's discharge permit. If seasonal
requirements exist, enter the most stringent effluent
concentration.
What is the monthly average effluent TSS concentration allowed
by the facility's discharge permit, in mg/l?
Lower Bound:
Upper Bound:
0
200
9. Design Average Daily Flow, gpd.
Typically, a treatment facility is designed to process a given
average daily flow.
Enter the average daify design flow, in gallons per day, to the
plant.
Lower Bound:
Upper Bound:
0
20,000,000
10. Design Influent BOD5 Concentration, mg/1.
What is the design influent BODS concentration of the
POTW, in mg/1?
What is the design influent BODS concentration of the POTW,
in mg/l? If unknown, enter 0.
Lower Bound: 0
Upper Bound: ' 1,000
-35-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
11. Design Influent TSS Concentration, mg/I.
What is the design influent TSS concentration of the POTW,
in mg/I?
What is the design influent TSS concentration of the POTW, in
mg/l? If unknown, enter 0.
Lower Bound: 0
Upper Bound: 1,000
-36-
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POTW EXPERT DATA ENTRY
WASTEWATER RECIRCULATION
AERATED BIO-FILTER
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Recirculation Around Fixed Film Process.
Recirculation, for the purposes of this analysis, is the pumping
of wastewater from downstream of the fixed film process to a
point upstream of the process, with the intention of increasing
the exposure of wastewater to the filter media. Typically, the
volume of wastewater recirculated is equal to or greater than
the average flow of the POTW.
Can this POTW recirculate wastewater from the effluent of
the fixed film process (in ABFs, from the effluent of the
biocell) to the influent of the process, and is this type of
recirculation currently in use in this POTW?
Can this POTW recirculate wastewater from the effluent of the
fixed film process to the influent of the process, and if so, is the
recirculation used?
Available and in use
Available but not used
Not available
2a. Recirculation Around Fixed Film Process Volume, gpd.
When recirculation around Kxed Film Process is available and
in use, what is the volume of wastewater recirculated from the
effluent of the fixed film process to the influent of the fixed
film process (effluent of the biocell for ABF POTWs), in
gallons per day?
What volume of wastewater is recirculated from the effluent of
the fixed film process to the influent of the process, in gallons
per day?
Lower bound:
Upper bound:
0
50,000,000
-37-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
2b. Recirculation Around Fixed Film Process Volume, gpd.
When recirculation around Fixed Film Process is available but
not in use, what is the maximum volume of wastewater, in
gallons per day, which the recirculation pumps can transfer
from the effluent of the fixed film process (effluent of the
biocell for ABF POTWs) to the influent of the fixed film
process?
What volume of wastewater could be recirculated from the
effluent of the fixed film process to the influent of the process, in
gallons per day?
Lower bound:
Upper bound:
0
50,000,000
3. Recirculation Through Final Clarifier.
Recirculation, for the purposes of this analysis, is the pumping
of wastewater from downstream of the fixed film process to a
point upstream of the process, with the intention of increasing
the exposure of wastewater to the filter media. Typically, the
volume of wastewater recirculated is equal to or greater than
the average flow of the POTW.
Can this POTW recirculate wastewater from the final clarifier
to the influent of the fixed film process, and is this type of
recirculation currently in use in this POTW?
Can this POTW recirculate wastewater from the final clarifier to
the influent of the fixed film process, and if so, is the
recirculation used?
Available and in use
Available but not used
Not available
4. Recirculation Through Final Clarifier Controllable.
Do the controls and/or recirculation pumps of this POTW
allow recirculation from the final clarifier to the influent of
the fixed film process to be turned off?
Can recirculation from the final clarifier to the influent of the
fixed film process be turned off?
Yes
No
-38-
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ANSWER OPTIONS
5. Recirculation Through Final Clarifier Volume, gpd. Lower bound: 0
Upper bound: 50,000,000
What is the volume of wastewater recirculated from the final
clarifier to the influent of the fixed film process, in gallons per
day?
What volume of wastewater is recirculated from the final
clarifier to the influent of the fixed film process, in gallons per
day?
-39-
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POTW EXPERT DATA ENTRY
WASTEWATER RECIRCULATION
TRICKLING FILTER/ROTATING BIOLOGICAL CONTACTOR
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Recirculation Around Fixed Film Process.
Recirculation, for the purposes of this analysis, is the pumping
of wastewater from downstream of the fixed film process to a
point upstream of the process, with the intention of increasing
the exposure of wastewater to the filter media. Typically, the
volume of wastewater recirculated is equal to or greater than
the average flow of the POTW.
Can this POTW recirculate wastewater from the effluent of
the fixed film process (in ABFs, from the effluent of the
biocell) to the influent of the process, and is this type of
recirculation currently in use in this POTW?
Can this POTW recirculate wastewater from the effluent of the
fixed film process to the influent of the process, and if so, is the
recirculation used?
Available and in use
Available but not used
Not available
2a. Recirculation Around Fixed Film Process Volume, gpd.
When recirculation around Fixed Film Process is available and
in use, what is the volume of wastewater recirculated from the
effluent of the fixed film process to the influent of the fixed
film process (effluent of the biocell for ABF POTWs), in
gallons per day?
What volume of wastewater is recirculated from the effluent of
the fixed film process to the influent of the process, in gallons
per day?
Lower bound:
Upper bound:
0
50,000,000
-40-
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SCREEftfBCT QUESTIONS
ANSWER OPTIONS
2b. Recirculation Around Fixed Film Process Volume, gpd.
When recirculation around Fixed Film Process is available but
not in use, what is the maximum volume of wastewater, in
gallons per day, which the recirculation pumps can transfer
from the effluent of the fixed film process (effluent of the
biocell for ABF POTWs) to the influent of the fixed film
process?
What volume of wastewater could be recirculated from the
effluent of the fixed film process to the influent of the process, in
gallons per day?
Lower bound:
Upper bound:
0
50,000,000
3. Recirculation Through Final Clarifier.
Recirculation, for the purposes of this analysis, is the pumping
of wastewater from downstream of the fixed film process to a
point upstream of the process, with the intention of increasing
the exposure of wastewater to the filter media. Typically, the
volume of wastewater recirculated is equal to or greater than
the average flow of the POTW.
Can this POTW recirculate wastewater from the final clarifier
to the influent of the fixed film process, and is this type of
recirculation currently in use in this POTW?
Can this POTW recirculate wastewater from the final clarifier to
the influent of the fixed film process, and if so, is the
recirculation used?
Available and in use
Available but not used
Not available
4. Recirculation Through Final Clarifier Controllable.
Do the controls and/or recirculation pumps of this POTW
allow recirculation from the final clarifier to the influent of
the fixed film process to be turned off?
Can recirculation from the final clarifier to the influent of the
fixed film process be turned off?
Yes
No
-41-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
5. Recirculation Through Final Clarifier Volume, gpd.
What is the volume of wastewater recirculated from the final
clarifier to the influent of the fixed film process, in gallons per
day?
What volume of wastewater is recirculated from the final
clarifier to the influent of the fixed film process, in gallons per
day?
Lower bound:
Upper bound:
0
50,000,000
6. Recirculation Through Final and Primary Clarifiers.
Recirculation, for the purposes of this analysis, is the pumping
of wastewater from downstream of the fixed film process to a
point upstream of the process, with the intention of increasing
the exposure of wastewater to the filter media. Typically, the
volume of wastewater recirculated is equal to or greater than
the average flow of the POTW.
Can this POTW recirculate wastewater from the final clarifier
to the influent of the primary clarifier(s), and is this type of
recirculation currently in use in this POTW?
Can this POTW recirculate wastewater from the final clarifier to
the influent of the primary clarifier, and if so, is the recirculation
used?
Available and in use
Available but not used
Not available
7. Recirculation Through Final and Primary Controllable.
Do the controls and/or recirculation pumps of this POTW
allow recirculation from the final clarifier to the influent of
the primary clarifier(s) to be turned off?
Can recirculation from the final clarifier to the influent of the
primary darifierfs) be turned off?
Yes
No
-42-
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ANSWER OPTIONS
8. Recirculation Through Final and Primary Volume, gpd.
What is the volume of wastewater recirculated from the final
clarifier to the influent of the primary clarifier(s), in gallons
per day?
What volume of wastewater is recirculated from the final
clarifier to the influent of the primary clarifier (s), in gallons per
day?
Lower bound: 0
Upper bound: 50,000,000
9. Waste Sludge Pump Capability.
Will the secondary sludge wasting pumps available in this
POTW allow the operators to pump a high concentration
sludge?
The two typical types of pumps for wasted sludge are positive
displacement pumps and centrifugal pumps. Often centrifugal
pumps will not successfully move sludge of greater than 10,000
mg/1 concentration, while positive displacement pumps will
handle sludge concentrations of 10,000 mg/1 or greater.
What concentration sludge can the secondary sludge wasting
pumps handle?
High concentration
Low concentration
-43-
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SCREEN
, sSf jf -f yA-vy-'XvKA
ANSWER OPTIONS
10. Operator's Secondary Wasting Policy.
From observations of the POTW operator's methods and
conversations with him/her about secondary sludge wasting,
which of the following most closely matches the operator's
policy:
Maintains a Sufficient Sludge Blanket - The operator
maintains a blanket of sludge in the final clarifier
necessary to keep the underflow concentration high.
Does Not Maintain a Sufficient Sludge Blanket - The
operator wastes any sludge in the final clarifier as it is
deposited. Little or no sludge blanket is allowed to
develop.
Retains Excessive Sludge - The operator maintains a
blanket of sludge in the final clarifier which is thicker
than necessary to create a high underflow concentration.
Typically, a sludge blanket must be at least two feet
thick to be considered excessive.
Does the operator maintain a sufficient sludge blanket?
Maintains a sufficient
sludge blanket
Does not maintain a
sufficient sludge blanket
Retains excessive sludge
-44-
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POTW EXPERT DATA ENTRY
FIXED FILM
TRICKLING FILTER
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Type of Filter Media.
What type of media is used for this trickling filter?
Rock media
Redwood slats i
Plastic :
What type of media is used for this trickling filter?
Rock
Redwood
Plastic
2. Specific Surface Area of Filter Media, sq fl/cu ft.
What is the specific surface area of the trickling filter media?
If unknown, enter 0.
Unit surface area information for various media types is
generally available in manufacturers' literature. Rock media
typically has a specific surface area of 13 square, feet/cubic
foot. This value will be used by POTW Expert if 0 is entered.
What is the specific surface area of the trickling filter media? If
unknown, enter 0.
Lower bound:
Upper bound:
0
100
3. Volume of Filter Media, cu ft
What is the total volume of the trickling filter media, in cubic
feet?
What is the total volume of the trickling filter media, in cubic
feet?
Lower bound: 0
Upper bound: 3,500,000
-45-
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SCREEN
QUESTIONS
ANSWER OPTIONS
4. Freezing Temperature for More Than One Month.
Is the fixed film process exposed to freezing temperatures for
more than one month annually. Filters that are covered are
usually not considered to be exposed to freezing temperatures.
Is the fixed film process exposed to freezing temperatures for
more than one month annually?
Yes
No
5. If/Where Sidestreams Are Returned to Plant.
Anaerobic sidestreams can contain high concentrations of
SBODS which will affect the performance capability of a fixed
film process. Indicate where the anaerobic sidestreams are
returned to the plant flow stream:
Not returned to the plant
Returned directly ahead of the fixed film process
Returned to a flow equalization tank or to a primary
clarifier prior to the fixed film process
Fixed film process refers to either the trickling filter or the
RBC process.
Where are anaerobic sidestreams returned to the plant flow
stream?
Not returned
Returned directly ahead of
fixed film process
Returned to processes
preceding fixed film
process
-46-
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POTW EXPERT DATA ENTRY
FIXED FILM
ROTATING BIOLOGICAL CONTACTOR (RBC)
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. SBODj Concentration, mg/1.
Enter the annual average soluble BOD5 concentration applied
to the RBC process. This value will be used to calculate the
SBODj loading to the RBC process in Ib/day.
If the soluble BODS concentration is unknown, enter 0.
What is the soluble BODS concentration applied to the RBC
process for the previous twelve months, in mg/l? If unknown,
enter ft
Lower bound:
Upper bound:
0
1,000
2. Percent of Flow to the First-Stage of the RBC.
Enter the percentage of influent flow applied to the first stage
of the RBC process. Typically, 100 % of the flow is applied to
the first stage. Occasionally, a portion of the flow will be
by-passed around the first stage.
Enter the percentage of influent flow applied to the first stage of
the RBC process.
Lower bound:
Upper bound:
1
100
-47-
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SCREEN
QUESTIONS
ANSWER OPTIONS
3. First Stage Media Surface Area, sq ft
Enter the total media surface area of the first stage of the
RBC process, in square feet. For multiple trains of RBCs,
total the surface areas of each first stage.
Surface area data for RBCs are generally available in
manufacturers' literature or in plant O&M manuals. If these
sources are unavailable or do not contain the needed
information, contact the manufacturer's representative or the
manufacturer to obtain the data.
Enter the total media surface area of the first stage of the RBC
process, in square feet. For multiple trains of RBCs, > total the
surface areas of each first stage.
Lower bound: 0
Upper bound: 5,000,000
4. Total Media Surface Area, sq ft
Enter the total media surface area of the RBC process, in
square feet. For multiple trains of RBCs, total the surface
areas of each train (including the first stage media surface
area).
Surface area data for RBCs are generally available in
manufacturers' literature or in plant O&M manuals. If these
sources are unavailable or do not contain the needed
information, contact the manufacturer's representative or the
manufacturer to obtain the data.
Enter the total media surface area of the RBC process, in
square feet.
Lower bound:
Upper bound:
0
22,240,000
-48-
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AMSWEH OPTIONS
5. Number of Stages.
Enter the number of stages provided for the RBC process. A
stage is defined as the number of RBC shafts, separated by a
baffle, that are operated in series.
Enter the number of stages provided.
Lower bound:
Upper bound:
1
5
6. HyWhere Sidestreams Are Returned to Plant.
Anaerobic sidestreams can contain high concentrations of
SBODj which will affect the performance capability of a fixed
film process. Indicate where the anaerobic sidestreams are
returned to the plant flow stream:
Not returned to the plant
Returned directly ahead of the fixed film process
Returned to a flow equalization tank or to a primary
clarifier prior to the treatment process
Fixed film process refers to either the trickling filter or the
RBC process.
Where are anaerobic sidestreams returned to the plant flow
stream?
Not returned
Returned directly ahead of
fixed film process
Returned to processes
preceding fixed film
process
-49-
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POTW EXPERT DATA ENTRY
FIXED FILM
ACTIVATED BIO-FILTER - DIFFUSED
ANSWER OPTIONS
1. Volume of Biocell Media, cu ft
What is the volume of the biocell media?
What is the volume of the biocell media?
Lower bound:
Upper bound:
0
500,000
2. Aeration basin volume, gal.
What is the volume of the aeration basin, in gallons?
What is the volume of the aeration basin, in gallons?
Lower bound: 0
Upper bound: 15,000,000
3. Oxygen Transfer Capacity, Ib
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter this
value in terms of the maximum pounds of oxygen per day that
can be supplied. Firm capacity (i.e., capacity with one blower
out of service) should be considered when identifying the
available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the oxygen transfer capacity, in Ib OJday? If the oxygen
transfer capacity is not available, enter 0.
Lower bound: 0
Upper bound: 50,000
-50-
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ANSWER OPTIONS
4. Air Blower Capacity, cu ft/min.
What is the maximum capacity of the blowers? Give the value
of full firm capacity, i.e., the maximum capacity that the
blowers can supply with one blower out of service.
The ratings on blowers may be in terms of actual or inlet cubic
feet per minute (e.g., ACFM, ICFM).
What is the blower capacity, in ACFM or ICFM? Allow for
blower down-time (Le., assume one blower is unavailable).
Lower bound: 0
Upper bound: 66,500
5. Type of Diffused Aeration System (see Help).
The types of aeration systems are:
Fine bubble diffusers with total coverage of the
aeration basin floor
Fine bubble diffusers in a side wall installation
Jet aeration (fine bubble)
« Static aerators (medium-size bubble)
Coarse bubble diffusers in a wide band pattern
Coarse bubble diffusers in a narrow band pattern
Select the type of aeration system that best describes the existing
equipment.
Fine bubble diffusers, total
floor coverage
Fine bubble diffusers, side
wall installation
Jet aerators (fine bubble)
Static aerators
(medium-size bubble)
Coarse bubble diffusers,
wide band pattern
Coarse bubble diffusers,
narrow band pattern
-51-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
6. Maximum Summer Wastewater Temp., *F.
The maximum wastewater temperature affects the oxygen
transfer capability of an aeration system because it affects
oxygen solubility. Maximum wastewater temperature will vary,
depending on geographic location, typically from 50°F to 70°F
(10°C to 21°C).
What is the maximum summertime wastewater temperature, in
degrees Fahrenheit?
Lower bound:
Upper bound:
32
86
7. Maximum Summer Air Temp., *F.
What is a typical maximum summer air inlet temperature?
What is the maximum summertime inlet temperature, in degrees
Fahrenheit?
8. Altitude above Mean Sea Level, ft.
Elevation affects performance of an aeration system, since the
saturation concentration of dissolved oxygen is lower at higher
altitudes.
What is the altitude of this facility above mean sea level, in feet?
9. DO Concentration in "Aerator", mg/1.
What is the average dissolved oxygen concentration recorded
in the "aerator" over the last 12 months, in mg/1?
Wliat is the "aerator" dissolved oxygen concentration, in mgll?
Lower bound:
Upper bound:
Lower bound:
Upper bound:
Lower bound:
Upper bound:
32
120
-120
10,000
0
10
-52-
-------
ANSWE& OPTIONS
10. DO Testing.
Indicate how often dissolved oxygen is measured in the
"aerator". Select the frequency closest to the plant's actual
testing routine.
If this test is not performed, select "Test not performed."
Frequency of tests is based on plant size according to the
following schedule:
Plant
Size
Small
Medium
Large
mgd
<2
2-10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the dissolved oxygen concentration measured in the
"aerator"?
3 times/week
2 times/day
3 times/day
Test not performed
ADDITIONAL QUESTIONS
Al. DO Accuracy.
Inaccurate dissolved oxygen values can be caused by several
factors, including:
A faulty DO meter
Faulty calibration procedures
Sampling location
Equipment wear or malfunction
Is the dissolved oxygen sampling conducted in a manner that is
likely to yield accurate results?
Yes
No
-53-
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SCBEEN TEXT QUESTIONS
ANSWER OPTIONS
A2. DO Representative.
Variable dissolved oxygen values can be caused by several
factors, including:
Inadequate oxygen supply
Operational practices
Sampling location
Does the DO sampling in the "aerator" reflect overall
conditions?
Yes
No
A3. Oxygen Transfer Efficiency.
Since the oxygen transfer capacity is unknown, the clean water
oxygen transfer efficiency is needed to estimate the capacity.
For diffused aeration systems, the plant design documents or
the manufacturers specification of the equipment may contain
a value for the oxygen transfer efficiency. Typically, this value
is expressed as a percent
If the oxygen transfer efficiency is unavailable, enter 0.
What is the clean water oxygen transfer efficiency, in percent? If
the oxygen transfer efficiency is unavailable, enter 0.
Lower bound:
Upper bound:
0
10
-54-
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POTW EXPERT DATA ENTRY
FIXED FILM
ACTIVATED BIO-FILTER - MECHANICAL
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Volume of Biocell Media, cu ft
What is the volume of the biocell media?
What is the volume of the biocell media?
Lower bound:
Upper bound:
0
500,000
2. Aeration Basin Volume, gal.
What is the volume of the aeration basin, in gallons?
What is the volume of the "aerators", in gallons?
Lower bound:
Upper bound:
0
15,000,000
3. Oxygen Transfer Capacity, Ib (yd.
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter this
value in terms of the maximum pounds of oxygen per day that
can be supplied. Firm capacity (i.e., capacity with one blower
out of service) should be considered when identifying the
available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the oxygen transfer capacity, in Ib OJday? If the oxygen
transfer capacity is not available, enter ft
Lower bound:
Upper bound:
0
50,000
-55-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
4. Total Aerator Motors' Horsepower.
Typically, surface aerators in a POTW are driven by electrical
motors. Marked upon the casing of these motors, or in the
plant documentation, will be a rating of the mechanical
horsepower that the motor is capable of producing. The total
of the horsepower ratings for all of the motors is necessary to
determine the amount of energy available for adding oxygen to
the wastewater.
What is the total rated mechanical horsepower of all of the
surface aerators?
Lower bound:
Upper bound:
0
1,400
5. Altitude above Mean Sea Level, ft.
Elevation affects performance of an aeration system, since the
saturation concentration of dissolved oxygen is lower at higher
altitudes.
What is the altitude of this facility above mean sea level, in feet?
Lower bound: -120
Upper bound: 10,000
6. Maximum Summer Wastewater Temp., °F.
The maximum wastewater temperature affects the oxygen
transfer capability of an aeration system because it affects
oxygen solubility. Maximum wastewater temperature will vary,
depending on geographic location, typically from 50°F to 70°F
(10°C to 21°C).
What is the maximum summertime wastewater temperature, in
degrees Fahrenheit?
Lower bound:
Upper bound:
32
86
-56-
-------
SCREEN TEXT &UESTIONS
ANSWER OPTIONS
7. DO Concentration in "Aerator," mg/1.
What is the average dissolved oxygen concentration recorded
in the "aerator" over the last 12 months, in mg/1?
What is the "aerator" dissolved oxygen concentration, in rag//?
Lower bound:
Upper bound:
0
10
8. DO Testing.
Please indicate how often dissolved oxygen is measured in the
"aerator". Select the frequency that is closest to the plant's
actual testing routine.
If this test is not performed, select "Test not performed."
Frequency of tests is based on plant size according to the
following schedule:
Plant
Size
Small
Medium
Large
mgd
<2
2-10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the dissolved oxygen concentration measured in the
"aerator"?
3 times/week
2 times/day
3 times/day
Test not performed
-57-
-------
SCREEN TEXT QUESTIONS
OPTIONS
ADDITIONAL QUESTIONS
Al. DO Accuracy.
Inaccurate dissolved oxygen values can be caused by several
factors, including:
A faulty DO meter
Faulty calibration procedures
Sampling location
Equipment wear or malfunction
Is the dissolved oxygen sampling conducted in a manner that is
likely to yield accurate results?
A2. DO Representative.
Variable dissolved oxygen values can be caused by several
factors, including:
Inadequate oxygen supply
Operational practices
Sampling location
Does the DO sampling in the "aerator" reflect overall
conditions?
Yes
No
Yes
No
-58-
-------
ANSWER OPTIONS
A3. Oxygen Transfer Rate. Lower bound: 0
Upper bound: 10
Since the oxygen transfer capacity is unknown, the clean water
oxygen transfer is needed to estimate the capacity.
For mechanical aeration devices, the plant design documents
or the manufacturers specification of the equipment may
contain a value for the oxygen transfer rate, dxygen transfer
rate is typically expressed hi pounds of oxygen per wire
horsepower-hour.
If the oxygen transfer rate is unavailable, enter 0.
What is the clean water oxygen transfer rate, in pounds of
oxygen per wire hoursepower-hour? If the oxygen transfer rate is
unavailable, enter 0.
-59-
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POTW EXPERT DATA ENTRY
FIXED FILM
TF/RBC/SECONDARY CLARIFIER - RECTANGULAR
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Total Surface Area, sq ft
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
Wliat is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound: 0
Upper bound: 60,000
2. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the depth at the weirs of the clarifier
which receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
,24
3. Launder Placement
Are the effluent launders for the rectangular clarifier(s)
located over the entire surface area or over just a portion of
the tank?
If the plant has a rectangular clarifier(s) that has a launder
attached to one end or very close to one end, select the
option "portion of tank."
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) which receive the greatest flow.)
Does the clariflerfs) have effluent launders over the total surface
area or over a portion of the tank?
Total surface area
Portion of tank
-60-
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SGKEiN H)tt QUESTIONS
ANSWER OPTIONS
4. Effluent BOD, Concentration, mg/1.
The effluent BOD5 concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent BODS.
Enter the annual average effluent BODS concentration, in mg/L
Lower bound:
Upper bound:
0
100
5. Effluent TSS Concentration, mgfl.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 me/1
effluent TSS.
Enter the annual average effluent TSS concentration, in mg/L
Lower bound:
Upper bound:
0
100
6. Months Effluent BODS Exceeds Permit Limit
The effluent BOD$ concentration is typically regulated by the
facility's National Pollution Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 BOD5 for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average of
45 mg/1 BOD5) for typical secondary treatment Exceeding
either of these conditions represents a violation for that
month.
Please indicate the number of months within the last year that
this facility has exceeded its monthly BOD5 permit limit.
Lower bound:
Upper bound:
0
12
-61-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
7. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
facility's National Pollution Discharge Elimination System
(NPDES) permit Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 TSS for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average of
45 mg/1 TSS) for typical secondary treatment Exceeding
either of these conditions represents a violation for that
month.
Enter the number of months within the last year that this facility
has exceeded its monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
8. Wasted Secondary Sludge Volume, gpd.
Sludge is typically wasted from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
attempt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational time.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have been made.
Enter the average daify volume of sludge wasted from the
secondary clarifier(s) for the previous twelve months, in gallons
per day.
Lower bound:
Upper bound:
0
5,000,000
-62-
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9. Wasted Secondary Sludge Concentration, mg/1.
If no thickening unit processes are available, sludge is typically
wasted as thick as possible from the secondary clarifier. This
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Sludpe Type Waste Cone., mg/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeration 7,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 m3/m2/d (500
gpd/sq ft).
-63-
-------
SCREEN TEXT QUESTIONS - , ANSWER OPTIONS
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film POTWs (1.21.26)
kg TSS (sludge)/
Process Type kg BODt removed
Trickling filter 0.9
RBC 1.0
ABF 1.0
Sludge Type Waste Cone., mg/i
Primary 50,000
Primary + Trickling Filter 35,000
Primary + RBC 35,000
Primary + ABF 30,000
Trickling Filter 20,000
RBC 20,000
ABF 10,000
Enter the average daily concentration of the waste secondary
sludge for the previous twelve months in mg/L If unknown, enter
0.
10. Wasted Sludge Concentration Reliability. Reliable
Unreliable
Do you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
-64-
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TEXT QUESTIONS
ANSWER OFHONS
11. Secondary Wasting Method.
Is sludge wasted from the final clarifier directly to a sludge
handling process(es), or is it wasted to the primary clarifier(s)?
Is sludge wasted to the primary clarifier(s) or directly to the
sludge handling process(es)?
(NOTE; If the operator employs recirculation from the final
clarifier to the influent of the primary clarifier(s) with no
other secondary sludge wasting, answer "Wasted to Primary
Clarifier.")
Wasted directly to sludge
handling
Wasted to Primary Clarifier
12. Operator's Secondary Wasting Policy.
From observations of the POTW operator's practices and
conversations with the operator about secondary sludge
wasting, which of the following most closely matches the
operator's policy.
Maintains a Sufficient Sludge Blanket -
The operator maintains a blanket of sludge in the final
clarifier necessary to keep the underflow concentration
high.
Does Not Maintain a Sufficient Sludge Blanket -
The operator wastes sludge in the final clarifier as it is
deposited. Little or no sludge blanket is allowed to
develop.
Retains excessive sludge -
The operator maintains a blanket of sludge in the final
clarifier that is thicker than necessary to create a high
underflow concentration. Typically, a sludge blanket
must be several feet thick to be considered excessive.
Does the operator maintain a sufficient sludge blanket?
Maintains a sufficient
sludge blanket
Does not maintain a
sufficient sludge blanket
Retains excessive sludge
-65-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
13. Control of Sludge Wasting.
Control of the sludge wasting process requires waste sludge
volume measurement and waste sludge sampling for
determining concentration. Optimum control for a sludge
wasting system includes automated volume control and
automated sampling.
Select the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the waste sludge volume measured and sampled?
Automated sampling and
volume control
Metered volume and hand
sampling
Hand measured volume
and hand sampling
Sampling or volume
measurement not available
ADDITIONAL QUESTIONS
Al. Effective Surface Area of Secondary Clarifier, sq ft
A portion of the total surface area for the secondary clarifier
is covered by effluent launders.
Surface loading on rectangular clarifiers with this type of
configuration is often exaggerated because of the location of
the effluent launders. To compensate for this increased
loading, an attempt is made to determine the "effective"
surface area available for solids liquid separation. The
effective surface area is usually less than the total surface area
of the clarifier. The effective area can be approximated by
using the area "served" by the launders (e.g., the square
footage of the portion of the tank covered by launders.
Normally, the "service area" extends beyond the furthest
inboard launder).
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, use the clarifier(s) that receives the greatest
flow.)
Enter the total effective surface area of the launders, insqft.
Lower bound: 0
Upper bound: 60,000
-66-
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POTW EXPERT DATA ENTRY
FIXED FILM
TF/RBC/SECONDARY CLAR1FIER - CIRCULAR
SCREEN TEXTQUESTIONS
ANSWER OPTIONS
1. Total Surface Area, sq ft.
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
What is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound: 0
Upper bound: 60,000
2. Weir Configuration.
Are the weirs of the circular clarifier(s) on the walls
(peripheral weirs) or are they suspended within the clarifier(s),
away from the walls?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) that receives the greatest flow.)
Select the clarifier configuration that best describes the facility.
"Donut" or interior
launders
Weirs on walls
3. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, enter the depth at the weirs of the clarifier
that receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
24
-67-
-------
SCREEN TEXT QUESTIONS
I '" " * f "> ">*,*. fy , ^v -Iw Xxj.^, '
^.-^^...^. ?............ ...:<., x. ,^^tj^^^.f.f^f>. !*!*..s. \
OPTIONS
4. Effluent BODS Concentration, mg/I.
The effluent BODj concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/l
effluent BODS.
Enter the annual average effluent BODS concentration in mg/L
Lower bound:
Upper bound:
0
100
5. Effluent TSS Concentration, mg/l.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit Typical secondary treatment requirements are 30 mg/l
effluent TSS.
Enter the annual average effluent TSS concentration in mg/L
Lower bound:
Upper bound:
0
100
6. Months Effluent BODS Exceeds Permit Limit
The effluent BODS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/l BODS for secondary treatment) or on
a weekly basis (e.g., exceeds 7-day average of 45 mg/l BOD5).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded its monthly BOD5 permit limit.
Lower bound:
Upper bound:
0
12
-68-
-------
sefiEEN ti-Dcr iciest IONS
7. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 TSS for secondary treatment) or on a
weekly basis (e.g., exceeds 7-day average of 45 mg/1 TSS).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded its monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
8. Wasted Sludge Volume, gpd.
Sludge is typically pumped from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
attempt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational time.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have to be made.
Enter the average daily volume of sludge wasted from the
secondary darifier(s) for the previous twelve months, in gallons
per day.
Lower bound:
Upper bound:
0
5,000,000
-69-
-------
SCREEN fexr attesttolls$
ANSWER OPTIONS
9. Wasted Secondary Sludge Concentration, mg/1.
Lower bound: 0
Upper bound: 15,000
wastea as tniCK as possioie irom me seconaary cianner. mis
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Sludge Type
Waste Cone., mg/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeration 7,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 m3/m2/d (500
gpd/sq ft).
-70-
-------
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film PQTWs ri.21.2fH
kg TSS (sludge)/
Process "type kg BOD, removed
Trickling filter 0 9
RBC L"0
ABF L0
Sludge Type Waste Cone., mp/l)
Primary 50,000
Primary + Trickling Filter 35,000
Primary + RBC 35,000
Primary -I- ABF 30,000
Trickling Filter 20,000
20,000
10,000
Enter the average daily concentration of the waste secondary
sludge for the previous twelve months in mg/L If unknown.
enter 0.
10. Wasted Sludge Concentration Reliability. . Reliable
r» -j . * Unreliable
-Uo you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
-71-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
11. Secondary Wasting Method.
Is sludge wasted from the final clarifier directly to a sludge
handling process(s), or is it wasted to the primary clarifier(s)?
Is sludge wasted to the primary clarifier(s) or directly to the
sludge handling process (es)?
(NOTE; If the operator employs recirculation from the final
clarifier to the influent of the primary clarifier(s) with no
other secondary sludge wasting, answer "Wasted to Primary
Clarifier.")
Wasted directly to sludge
handling
Wasted to Primary Clarifier
12. Operator's Secondary Wasting Policy.
From observations of the POTW operational practices and
conversations with the operator about secondary sludge
wasting, which of the following most closely matches the
operator's policy?
Maintains a Sufficient Sludge Blanket -
The operator maintains a blanket of sludge in the final
clarifier necessary to keep the underflow concentration
high.
Does Not Maintain a Sufficient Sludge Blanket -
The operator wastes sludge in the final clarifier as it is
deposited. Little or no sludge blanket is allowed to
develop.
Retains Excessive Sludge -
The operator maintains a blanket of sludge in the final
clarifier that is thicker than necessary to create a high
underflow concentration. Typically, a sludge blanket
must be several feet thick to be considered excessive.
Does the operator maintain a sufficient sludge blanket?
Maintains a sufficient
sludge blanket
Does not maintain a
sufficient sludge blanket
Retains excessive sludge
-72-
-------
scfieiwiflDcr QUESTIONS ANSWER OPTIONS
13. Control of Sludge Wasting. . Automated sampling and
0*1*1.,. . volume control
Control of the sludge wasting process requires waste sludge Metered volume and hand
volume measurement and waste sludge sampling for' sampling
determining concentration. Optimum control for a sludge Hand measured volume
wasting system includes automated volume control and and hand sampling
automated sampling. . Sampling or volume
c ,......,, measurement not available
belect the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the waste sludge volume measured and sampled?
-73-
-------
POTW EXPERT DATA ENTRY
FIXED FILM
ABF/SECONDARY CLARIFIER - RECTANGULAR
SCREEN
ANSWER OPTIONS
1. Total Surface Area, sq ft
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
What is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound:
Upper bound:
0
60,000
2. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, enter the depth at the weirs of the clarifier
that receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
24
-74-
-------
SCREEN TEXT QUESTiONS
ANSWER OPTIONS
3. Launder Placement
Are the effluent launders for the rectangular clarifier(s)
located over the entire surface area or over just a portion of
the tank?
If the plant has rectangular clarifier(s) that have a launder
attached to one end or very close to one end, select the
option "portion of tank."
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) which receive the greatest flow.)
Does the darifier(s) have effluent launders over the total surface
area or over a portion of the tank?
Total surface area
Portion of tank
4. Return Sludge Removal Mechanism.
Which of the following mechanisms are used for sludge
removal from the rectangular clarifier(s)?
Cocurrent Scraper -
sludge is scraped to hoppers moving in the same
direction as the flow of the wastewater
Countercurrent Scraper -
sludge is scraped to hoppers moving against the flow of
the wastewater
No Mechanical Removal
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the sludge removal mechanism of the
clarifier(s) that receive the greatest flow.)
Select the appropriate return sludge mechanism.
Cocurrent scraper
Countercurrent scraper
No mechanical removal
-75-
-------
SCREEN TEXT QUESTIONS
ANSWEfi OPTIONS
5. Minimum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment growth process used.
What is the minimum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the lower bound
of the functioning range over which flow can be varied)?
(NOTE: Even if the return flow pumps do not have variable
flow, it may be possible to use timers to reduce the flow
volume.)
What is the minimum return sludge flow rate, in gallons per
day?
Lower bound:
Upper bound:
0
20,000,000
6. Maximum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the maximum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the upper bound
of the functioning range over which flow can be varied)?
What is the maximum return sludge flow rate, in gallons per
day?
Lower bound: 0
Upper bound: 20,000,000
-76-
-------
ANSjtfift OPTIONS
7. RAS Flow Rate Testing.
Indicate how often the instantaneous measurement of the
return sludge flow rate is recorded. Select the frequency
closest to plant's actual testing routine.
If this test is not performed, select 'Test not performed."
If the facility does not have the capability to make
instantaneous return sludge flow measurements, answer "Not
able to perform test."
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
>10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the instantaneous return sludge flow rate
measured?
3 times/week
2 times/day
3 times/day
Test not performed
Not able to perform test
8. Effluent BODS Concentration, mg/1.
The effluent BOD5 concentration is regulated by the National
Pollutant Discharge Elimination System (NPDES) permit.
Typical secondary treatment requirements are 30 mg/1 effluent
BOD5.
Enter the annual average effluent BOD5 concentration in mg/L
9 Lower bound:
Upper bound:
0
100
-77-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
9. Effluent TSS Concentration, mg/1.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mgA
effluent TSS.
Enter the annual average effluent TSS concentration in mgll
Lower bound:
Upper bound:
0
100
10. Months Effluent BODS Exceeds Permit Limit
The effluent BODS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 BODS for secondary treatment) or on
a weekly basis (e.g., exceeds 7-day average of 45 mg/1 BOD5).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded its monthly BOD s permit limit.
Lower bound:
Upper bound:
0
12
11. Months Effluent TSS Exceeds Permit Limit.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 TSS for secondary treatment) or on a
weekly basis (e.g., exceeds 7-day average of 45 mg/I TSS).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded Us monthly TSS permit limit
Lower bound:
Upper bound:
0
12
-78-
-------
ANSWER OPTIONS
12. Wasted Secondaiy Sludge Volume, gpd. . Lower bound: 0
01 A «. « J ^ * UPPer bound: 5,000,000
bludge is typically wasted from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
attempt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational time.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have been made.
Enter the average daify volume of sludge wasted from the
secondary clarifier(s) for the previous twelve months, in gallons
per day.
-79-
-------
SCREEN TEXT QUESTIONS
OPTIONS
13. Wasted Secondary Sludge Concentration, mg/1.
If no thickening unit processes are available, sludge is typically
wasted as thick as possible from the secondary clarifier. This
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Lower bound: 0
Upper bound: 25,000
Sludge Type
Waste Cone., mg/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeration 7,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 mVmVd (500
gpd/sqft).
-80-
-------
ANSWER OPTfOHS
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film POTWs (1.21.261
kg TSS (sludge)/
Process Type kg BODc removed
Trickling filter 0 9
RBC 1.0
ABF 1.0
Sludge Type Waste Cone., mp/1
Primary 50,000
Primary + Trickling Filter 35,000
Primary + RBC 35,000
Primary + ABF 30,000
Trickling Filter 20,000
RBC 20,000
ABF 10,000
Enter the average daify concentration of the waste secondary
sludge for the previous twelve months in mg/L If unknown, enter
14. Wasted Sludge Concentration Reliability. Reliable
. Unreliable
Do you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
-81-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
15. Secondary Wasting Method.
Is sludge wasted from the final clarifier directly to a sludge
handling process(es), or is it wasted to the primary clarifier(s)?
Is sludge wasted to the primary clarifier(s) or directly to the
sludge handlingprocess(es)?
(NOTE; If the operator employs recirculation from the final
clarifier to the influent of the primary clarifier(s) with no
other secondary sludge wasting, answer "Wasted to Primary
Clarifier.")
Wasted directly to sludge
handling
Wasted to Primary Clarifier
16. Control of Sludge Wasting.
Control of the sludge wasting process requires waste sludge
volume measurement and waste sludge sampling for
determining concentration. Optimum control for a sludge
wasting system includes automated volume control and
automated sampling.
Select the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the waste sludge volume measured and sampled?
Automated sampling and
volume control
Metered volume and hand
sampling
Hand measured volume and
hand sampling
Sampling or volume
measurement not available
-82-
-------
scReiNtecrQUESTIONS fc/ ANSWER OPTIONS
ADDITIONAL QURSTTONS Lower bound: 0
* Upper bound: 60,000
Al. Effective Surface Area of Secondary Clarifier, sq ft
A portion of the total surface area for the secondary clarifiers
is covered by effluent launders.
Surface loading on rectangular clarifiers with this type of
configuration is often exaggerated because of the location of
the effluent launders. To compensate for this increased
loading, an attempt is made to determine the "effective"
surface area available for solids liquid separation. The
effective surface area is usually less than the total surface area
of the clarifier. The effective area can be approximated by
using the area "served" by the launders (e.g., the square
footage of the portion of the tank covered by launders.
Normally the "surface area" extends beyond the furthest
inboard launder).
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, use the clarifiersfs) which receive the greatest
flow.)
Enter the total effective surface area of the launders, in square
feet.
-83-
-------
POTW EXPERT DATA ENTRY
FIXED FILM
ABF/SECONDARY CLARIFIER - CIRCULAR
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Total Surface Area, sq ft
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
What is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound: 0
Upper bound: 60,000
2. Weir Configuration.
Are the weirs of the circular clarifier(s) on the walls
(peripheral weirs) or are they suspended within the clarifiers,
away from the walls?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) that receive the greatest flow.)
Select the clarifier(s) configuration that best describes the
facility.
"Donut" or interior
launders
Weirs on walls
3. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes^ enter the depth at the weirs of the clarifier
that receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
24
-84-
-------
4. Sludge Removal Mechanism.
Which of the following mechanisms are used for potential
sludge removal from the circular clarifier(s)?
Rapid Withdrawal -
sludge is removed from multiple draw-off points using
the "suction" created by hydraulic differential
Scraper to Hopper -
sludge is scraped to a single bottom hopper for removal
Both of the Above
No Mechanical Removal
Select the appropriate sludge removal mechanism.
Rapid withdrawal
Scraper to hopper
Both of the above
No mechanical removal
5. Minimum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the minimum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the lower bound
of the functioning range over which flow can be varied)?
(NOTE; Even if the return flow pumps do not have variable
flow, it may be possible to use timers to reduce the flow
volume.)
What is the minimum return sludge flow rate, in gallons per
day?
Lower bound: 0
Upper bound: 20,000,000
-85-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
6. Maximum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the maximum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the upper bound
of the functioning range over which flow can be varied)?
What is the maximum activated sludge flow rate, in gallons per
day?
Lower bound:
Upper bound:
0
20,000,000
7. RAS Flow Rate Testing.
Indicate how often the instantaneous measurement of the
return sludge flow rate is recorded. Select the frequency that
is closest to plant's actual testing routine.
If this test is not performed, select "Test not performed."
If the facility does not have the capability to make
instantaneous return sludge flow measurements, answer "Not
able to perform test"
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
>10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the instantaneous return sludge flow rate
measured?
3 times/week
2 times/day
3 times/day
Test not performed
Not able to perform test
-86-
-------
SCREEN TEXT QUESTiONS
ANSWB* OPTIONS
8. Effluent BOD, Concentration, mg/L
The effluent BOD5 concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent BOD,.
Enter the annual average effluent BOD5 concentration in mg/l.
Lower bound:
Upper bound:
0
100
9. Effluent TSS Concentration, mg/1.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent TSS.
Enter the annual average effluent TSS concentration in mg/l.
Lower bound:
Upper bound:
0
100
10. Months Effluent BOD, Exceeds Permit Limit
The effluent BODS concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/l BOD5 for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average of
45 mg/l BOD5). Exceeding either of these conditions
represents a violation for that month.
Enter the number of months that this facility has exceeded its
monthly BOD$ permit limit.
* Lower bound:
Upper bound:
0
12
-87-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
11. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 TSS for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average of
45 mg/1 TSS). Exceeding either of these conditions represents
a violation for that month.
Enter the number of months that this facility has exceeded its
monthly TSS permit limit.
Lower bound:
Upper bound:
0
100
12. Wasted Secondary Sludge Volume, gpd.
Sludge is typically wasted from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
atte'mpt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational time.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have been made.
Enter the average daily volume of sludge wasted from the
secondary clarifier(s) for the previous twelve months, in gallons
per day.
Lower bound: 0
Upper bound: 5,000,000
-88-
-------
13. Wasted Secondary Sludge Concentration, mg/1. Lower bound: 0
_ 'Upper bound: 25,000
It no thickening unit processes are available, sludge is typically
wasted as thick as possible from the secondary clarifier. This
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Sludge Type Waste Cone., mg/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeration 7,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 m3/m2/d (500
gpd/sq ft).
-89-
-------
SCREEN TEXT QUESTIONS ; " ANSWER OPTIONS
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film POTWs f 1.21.26)
kg TSS (sludge)/
Process Type kg BOD< removed
Trickling filter 0.9
RBC 1.0
ABF 1.0
Sludge Type Waste Cone.. mg/D
Primary 50,000
Primary + Trickling Filter 35,000
Primary + RBC 35,000
Primary + ABF 30,000
Trickling Filter 20,000
RBC 20,000
ABF 10,000
Enter the average daify concentration of the waste secondary
sludge for the previous twelve months in mgll If unknown, enter
0.
14. Wasted Sludge Concentration Reliability. Reliable
Unreliable
Do you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
-90-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
15. Secondary Wasting Method.
Is sludge wasted from the final clarifier directly to a sludge
handling process(es), or is it wasted to the primary clarifier(s)?
Is sludge wasted to the primary clarifier (s) or directly to the
sludge handlingprocess(es)?
(NOTE: If the operator employs recirculation from the final
clarifier to the influent of the primary clarifier(s) with no
other secondary sludge wasting, answer "Wasted to Primary
Clarifier.")
Wasted directly to sludge
handling
Wasted to Primary Clarifier
16. Control of Sludge Wasting.
Control of the sludge wasting process requires waste sludge
volume measurement and waste sludge sampling for
determining concentration. Optimum control for a sludge
wasting system includes automated volume control and
automated sampling.
Select the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the wasted sludge volume measured and sampled?
Automated sampling and
volume control
Metered volume and hand
sampling
Hand measured volume
and hand sampling
Sampling or volume
measurement not available
-91-
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POTW EXPERT DATA ENTRY
SUSPENDED GROWTH
AERATION BASIN - DIFFUSED
SCREEN
QUESTIONS
ANSWER OPTIONS
1. Aeration Basin volume, gal.
What is the volume of the "aerator", in gallons?
Wliat is the volume of the aeration basin, in gallons?
Lower bound: 0
Upper bound: 15,000,000
2. Oxygen Transfer Capacity, Ib OJd.
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter this
value in terms of the maximum pounds of oxygen per day that
can be supplied. Firm capacity (i.e., capacity with one blower
out of service) should be considered when identifying the
available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the oxygen transfer capacity, in Ib OJd? If the oxygen
transfer capacity is not available, enter 0.
Lower bound: 0
Upper bound: 50,000
3. Air Blower Capacity, cu fl/min.
What is the maximum capacity of the blowers? Give the value
of full firm capacity, i.e., the maximum capacity that the
blowers can supply with one blower out of service.
The ratings on blowers may be in terms of actual or inlet cubic
feet per minute (e.g., ACFM, ICFM).
Wliat is the blower capacity, in ACFM or ICFM? Allow for
blower down-time (Le., assume that one blower is unavailable).
Lower bound:
Upper bound:
0
66,500
-92-
-------
SCREE
EED
ANSWER OPTION^
4. Type of Diffused Aeration System (see Help).
The types of aeration systems are:
Fine bubble diffusers with total coverage of the aeration
basin floor
Fine bubble diffusers in a side wall installation
Jet aeration (fine bubble)
Static aerators (medium-size bubble)
Coarse bubble diffusers in a wide band pattern
Coarse bubble diffusers in a narrow band pattern
Select the type of aeration system that best describes the existing
equipment.
5. Maximum Summer Wastewater Temp., °F.
The maximum wastewater temperature affects the oxygen
transfer capability of an aeration system because it affects
oxygen solubility. Maximum wastewater temperature will vary,
depending on geographic location, typically from 50°F to 70°F
(10°C to 21°C).
What is the maximum summertime wastewater temperature, in
degrees Fahrenheit?
6. Maximum Summer Air Temp., °F.
What is a typical maximum summer air inlet temperature?
What is the maximum summertime Met temperature, in degrees
Fahrenheit?
Fine bubble diffusers, total
floor coverage
Fine bubble diffusers, side
wall installation
Jet aerators (fine bubble)
Static aerators
(medium-size bubble)
Coarse bubble diffusers,
wide band pattern
Coarse bubble diffusers,
narrow band pattern
Lower bound:
Upper bound:
32
86
Hower bound:
Upper bound:
32
120
-93-
-------
SCREEN
QUESTIONS
ANSWER OPTIONS
7. Altitude above Mean Sea Level, ft
Elevation affects performance of an aeration system, since the
saturation concentration of dissolved oxygen is lower at higher
altitudes. '
What is the altitude of this facility above mean sea level, in feet?
Lower bound: -120
Upper bound: 10,000
8. DO Concentration in "Aerator," mg/I.
What is the average dissolved oxygen concentration recorded
in the "aerator" over the last 12 months, in mg/1?
What is the "aerator" dissolved oxygen concentration, in mgll?
Lower bound:
Upper bound:
0
10
9. DO Testing.
Indicate how often dissolved oxygen is measured in the
"aerator." Select the frequency closest to the plant's actual
testing routine.
If this test is not performed, select "Test not performed."
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the dissolved oxygen concentration measured in the
"aerator?"
3 times/week
2 times/day
3 times/day
Test not performed
-94-
-------
OPTIONS
ADDITIONAL QUESTIONS
Al. DO Accuracy. Yes
No
Inaccurate dissolved oxygen values can be caused by several
factors, including:
A faulty DO meter
Faulty calibration procedures
Sampling location
Equipment wear or malfunction
Is the dissolved oxygen sampling conducted in a manner that is
likely to yield accurate results?
A2. DO Representative. Yes
No
Variable dissolved oxygen values can be caused by several
factors, including:
Inadequate oxygen supply
Operational practices
Sampling location
Does the DO sampling in the "aerator" reflect overall
conditions?
-95-
-------
SCREEN TEXT QUESTIONS : \, ANSWER OPTIONS
A3. Oxygen Transfer Efficiency. Lower bound: 0
Upper bound: 10
Since the oxygen transfer capacity is unknown, the clean water
oxygen transfer efficiency is needed to estimate the capacity.
For diffusion aeration systems, the plant design documents or
the manufacturers specification of the equipment may contain
a value for the oxygen transfer efficiency. Typically, this value
is expressed as a percent.
If the oxygen transfer efficiency is unavailable, answer 0.
What is the dean water oxygen transfer efficiency, in percent?
If the oxygen transfer efficiency is unavailable, answer 0.
-96-
-------
POTW EXPERT DATA ENTRY
SUSPENDED GROWTH
AERATION BASIN - MECHANICAL
SCREEN TEtfT OOESTlONS
- '"'.-.. ^ ..'.."" '
ANSWER OPTIONS
1. Aeration Basin Volume, gal.
What is the volume of the aeration basin, in gallons.
What is the volume of the aeration basin, in gallons?
Lower bound:
Upper bound:
0
15,000,000
2. Oxygen Transfer Capacity, Ib Oj/d.
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter this
value in terms of the maximum pounds of oxygen per day that
can be supplied. Firm capacity (e.g., capacity with one blower
out of service) should be considered when identifying the
available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the oxygen transfer capacity, in Ib OJday? If the oxygen
transfer capacity is not available, enter 0.
Lower bound:
Upper bound:
0
50,000
3. Total Aerator Motors' Horsepower.
Typically, surface aerators in a POTW are driven by electrical
motors. Marked upon the casing of these motors, or in the
plant documentation, will be a rating of the mechanical
horsepower that the motor is capable of producing. The total
of the horsepower ratings for all of the motors is necessary to
determine the amount of energy available for adding oxygen to
the wastewater.
What is the total rated mechanical horsepower of all of the
surface aerators?
Lower bound: 0
Upper bound: 1,400
-97-
-------
SCREEN TEXT QUESTIONS
' ^wwsssvBiifwevj -ow- '«~<'' ,,(?>
Xq^jpq^vx i-^^»i,> y-y^O- -0-KC-v SP'f'i ^ J'HJ'' nHn S
ANSw^o^ptto^^ ,;
' ' "'^/ '" J^4^'X4X.',, i
4. Altitude above Mean Sea Level, ft
Elevation affects performance of an aeration system, since the
saturation concentration of dissolved oxygen is lower at higher
altitudes.
What is the altitude of this facility above mean sea level, in
feet?
Lower bound:
Upper bound:
-120
10,000
5. Maximum Summer Wastewater Temp., °F.
The maximum wastewater temperature affects the oxygen
transfer capability of an aeration system because it affects
oxygen solubility. Maximum wastewater temperature will vary,
depending on geographic location, typically from 50°F to 70°F
(10°C to 21°C).
Wfiat £y the maximum summertime wastewater temperature, in
degrees Fahrenheit?
Lower bound:
Upper bound:
32
86
6. DO Concentration in "Aerator," mg/I.
What is the average dissolved oxygen concentration recorded
in the "aerator" over the last 12 months, in mg/1?
Wfiat is the "aerator" dissolved oxygen concentration, in mg/l?
"Lower bound:
Upper bound:
0
10
-98-
-------
ANSWER OPTIONS
7. DO Testing.
Indicate how often dissolved oxygen is measured in the
"aerator." Select the frequency closest to the plant's actual
testing routine.
If this test is not performed, select "Test not performed."
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
>10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the dissolved oxygen concentration measured in the
"aerator?"
3 times/week
2 times/day
3 times/day
Test not performed
ADDITIONAL QUESTIONS
Al. DO Accuracy.
Inaccurate dissolved oxygen values can be caused by several
factors, including:
A faulty DO meter
Faulty calibration procedures
Sampling location
Equipment wear or malfunction
Is the dissolved oxygen sampling conducted in a manner that is
likely to yield accurate results?
Yes
No
-99-
-------
SCREEN TEXT QUESTIONS;
ANSWER OPTIONS
A2. DO Representative.
Variable dissolved oxygen values can be caused by several
factors, including:
1) Inadequate oxygen supply.
2) Operational practices.
3) Sampling location.
Does the DO sampling in the "aeration" reflect overall
conditions?
Yes
No
A3. Oxygen Transfer Rate.
Since the oxygen transfer capacity is unknown, the clean water
oxygen transfer rate is needed to estimate the capacity.
For mechanical aeration devices, the plant design documents
or the manufacturers specification of the equipment may
contain a value for the oxygen transfer rate. Oxygen transfer
rate is typically expressed in pounds of oxygen per wire
horsepower-hour.
If the oxygen transfer rate is unavailable, answer 0.
What is the clean water oxygen transfer rate, in pounds of
oxygen per wire horsepower-hour?
If the oxygen transfer rate is unavailable, answer 0.
Lower bound:
Upper bound:
0
10
-100-
-------
POTW EXPERT DATA ENTRY
SUSPENDED GROWTH
SECONDARY CLARIFIER - RECTANGULAR
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Total Surface Area, sq ft
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
What is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound:
Upper bound:
0
60,000
2. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the depth at the weirs of the clarifier
that receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
24
-101-
-------
SCREEN TOT QUESTIONS
ANSWER OPTIONS
3. Launder Placement.
Are the effluent launders for the rectangular clarifier(s)
located over the entire surface area or over just a portion of
the tank?
If the plant has a rectangular clarifier(s) that has a launder
attached to one end or very close to one end, select the
option "portion of tank."
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) that receives the greatest flow.)
Doss the clarifter(s) have effluent launders over the total surface
area or over a portion of the tank?
Total surface area
Portion of tank
4. Return Sludge Removal Mechanism.
Which of the following mechanisms are used for sludge
removal from the rectangular clarifier(s)?
* Cocurrent Scraper -
sludge is scraped to hoppers moving in the same
direction as the flow of the wastewater
Countercurrent Scraper
sludge is scraped to hoppers moving against the flow of
the wastewater
No Mechanical Removal
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the sludge removal mechanism of the
clarifier(s) that receive the greatest flow.)
Select the appropriate return sludge mechanism.
Cocurrent scraper
Countercurrent scraper
No mechanical removal
-102-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
5. Minimum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment growth process used.
What is the minimum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the lower bound
of the functioning range over which flow can be varied)?
(NOTE: Even if the return flow pumps do not have variable
flow, it may be possible to use timers to reduce the flow
volume.)
What is the minimum return sludge flow rate, in gallons per
day?
Lower bound:
Upper bound:
0
20,000,000
6. Maximum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the maximum rate at which return sludge can be
removed from the secondary clarifier(s) (e.g., the upper bound
of the functioning range over which flow can be varied)?
What is the maximum return sludge flow rate, in gallons per
day?
Lower bound:
Upper bound:
0
20,000,000
-103-
-------
SCREEN
ANSWER OPTIONS
7. RAS Flow Rate Testing.
Indicate how often the instantaneous measurement of return
sludge flow rate is recorded. Select the frequency closest to
plant's actual testing routine.
If this test is not performed, select "Test not performed."
If the facility does not have the capability to make
instantaneous return sludge flow measurements, answer "Not
able to perform test."
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
>10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the instantaneous return sludge flow rate
measured?
3 times/week
2 times/day
3 times/day
Test not performed
Not able to perform test
8. Effluent BODS Concentration, mg/1.
The effluent BOD5 concentration is regulated by the National
Pollutant Discharge Elimination System (NPDES) permit.
Typical secondary treatment requirements are 30 mg/1 effluent
BODj.
Enter the annual average effluent BODS concentration in mgll
Lower bound:
Upper bound:
0
100
-104-
-------
9. Effluent TSS Concentration, mg/1.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 me/I
effluent TSS.
Enter the annual average effluent TSS concentration in mg/L
Lower bound:
Upper bound:
0
100
10. Months Effluent BODS Exceeds Permit Limit
The effluent BODS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/I BOD$ for secondary treatment) or on
a weekly basis (e.g., exceeds 7-day average of 45 mg/1 BODS).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded its monthly BODS permit limit.
Lower bound:
Upper bound:
0
12
11. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 TSS for secondary treatment) or on a
weekly basis (e.g., exceeds 7-day average of 45 mg/1 TSS).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months within the last year that this facility
has exceeded its monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
-105-
-------
r 1 ^ _,S -,V,X %
SCREEN TEXT QUEST0NS
ANSWER OPTIONS
12. Wasted Secondary Sludge Volume, gpd.
Sludge is typically wasted from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
attempt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational time.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have been made.
Enter the average daify volume of sludge wasted from the
secondary darifier(s) for the previous twelve months, in gallons
per day.
Lower bound:
Upper bound:
0
5,000,000
-106-
-------
ANSWER OPTIONS
13. Wasted Secondary Sludge Concentration, mg/I. Lower bound: 0
Upper bound: 25,000
If no thickening unit processes are available, sludge is typically
wasted as thick as possible from the secondary clarifier. This
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Sludge Type Waste Cone., mg/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeration 7,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 m3/m2/d (500
gpd/sq ft).
-107-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film POTWs (1.21.26)
Process Type
Trickling filter
RBC
ABF
kg TSS (sludge)/
kg BODc removed
0.9
1.0
1.0
Sludge Type
Primary
Primary + Trickling Filter
Primary -h RBC
Primary + ABF
Trickling Filter
RBC
ABF
Waste Cone., mg/1)
50,000
35,000
35,000
30,000
20,000
20,000
10,000
Enter the average daily concentration of the waste secondary
sludge for the previous twelve months in mg/L If unknown, enter
0.
14. Wasted Sludge Concentration Reliability.
Do you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
Reliable
Unreliable
-108-
-------
SCREEN TEXT QUESTION!
ANSWER OPTIONS
15. Control of Sludge Wasting.
Control of the sludge wasting process requires waste sludge
volume measurement and waste sludge sampling for
determining concentration. Optimum control for a sludge
wasting system includes automated volume control and
automated sampling.
Select the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the waste sludge volume measured and sampled?
9 Automated sampling and
volume control
Metered volume and hand
sampling
Hand measured volume
and hand sampling
Sampling or volume
measurement not available
ADDITIONAL QUESTIONS
Al. Effective Surface Area of Secondary Clarifier, sq ft
A portion of the total surface area for the secondary clarifiers
is covered by effluent launders.
Surface loading on rectangular clarifiers with this type of
configuration is often exaggerated because of the location of
the effluent launders. To compensate for this increased
loading, an attempt is made to determine the "effective"
surface area available for solids liquid separation. The
effective surface area is usually less than the total surface area
of the clarifier. The effective area can be approximated by
using the area "served" by the Hunders (e.g., the square
footage of the portion of the tank covered by launders.
Normally the "surface area" extends beyond the furthest
inboard launder).
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, use the clarifiers(s) which receive the greatest
flow.)
Enter the total effective surface area of the launders, in square
feet.
Lower bound: 0
« Upper bound: 60,000
-109-
-------
POTW EXPERT DATA ENTRY
SUSPENDED GROWTH
SECONDARY CLARIFIER - CIRCULAR
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
1. Total Surface Area, sq it
What is the surface area of the secondary clarifier(s), in
square feet? If there are multiple tanks, enter the total
surface area of all of the tanks.
What is the total surface area of the secondary clarifier(s), in
square feet?
Lower bound: 0
Upper bound: 60,000
2. Weir Configuration.
Are the weirs of the circular clarifier(s) on the walls
(peripheral weirs) or are they suspended within the clarifier,
away from the walls?
(NOTE: If the plant has multiple secondary clarifiers with
different shapes, enter the launder configuration of the
clarifier(s) that receives the greatest flow.)
Select the clarifierfs) configuration that best describes the
facility.
"Donut" or interior launders
Weirs on walls
3. Depth Near the Weirs, ft
How deep is the secondary clarifier(s) at the weirs, in feet?
(NOTE; If the plant has multiple secondary clarifiers with
different shapes, enter the depth at the weirs of the clarifier
that receives the greatest flow.)
What is the depth of the clarifier(s) at the weirs, in feet?
Lower bound:
Upper bound:
0
24
-110-
-------
SCREEN TEXT QUESTIONS
f .'.".S V,
AtfSWfcB OFHONS
4. Sludge Removal Mechanism.
Which of the following mechanisms are used for potential
sludge removal from the circular clarifier(s)?
Rapid Withdrawal -
sludge is removed from multiple draw-off points using
the "suction" created by hydraulic differential
Scraper to Hopper -
sludge is scraped to a single bottom hopper for removal
Both of the Above
No Mechanical Removal
Select the appropriate sludge removal mechanism.
Rapid withdrawal
Scraper to hopper
Both of the above
No mechanical removal
5. Minimum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the minimum rate at which return sludge can be
removed from the secondary clarifier (e.g., the lower bound of
the functioning range over which flow can be varied)?
(NOTE: Even if the return flow pumps do not have variable
flow, it may be possible to use timers to reduce the flow
volume.)
What is the minimum return sludge flow rate, in gallons per
day?
Lower bound:
Upper bound:
0
20,000,000
-111-
-------
J UV"l"i"J.v
, ,. ,-
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
6. Maximum Return Sludge Flow Rate Possible, gpd.
Evaluation of a secondary clarifier(s) includes an evaluation of
the return sludge capability. The plant's flow volume
capabilities are compared to recommended ranges for the type
of treatment process used.
What is the maximum rate at which return sludge can be
removed from the secondary clarifier (e.g., the upper bound of
the functioning range over which flow can be varied)?
What is the maximum activated sludge flow rate, in gallons per
day?
Lower bound: 0
Upper bound: 20,000,000
7. RAS Flow Rate Testing.
Indicate how often the instantaneous measurement of return
sludge flow rate is recorded. Select the frequency closest to
plant's actual testing routine.
If this test is not performed, select "Test not performed."
If the facility does not have the capability to make
instantaneous return flow measurements, answer "Not able to
perform test"
Frequency of tests is based on plant size according to the
following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
>10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
How often is the instantaneous return sludge flow rate
measured?
3 times/week
2 times/day
3 times/day
Test not performed
Not able to perform test
-112-
-------
SCREEN TEXT QUESTIONS'
ANSWER OPTIONS
8. Effluent BOD, Concentration, mg/1.
The effluent BODS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent BOD5.
Enter the annual average effluent BODS concentration in mg/L
Lower bound:
Upper bound:
0
100
9. Effluent TSS Concentration, mg/1.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent TSS.
Enter the annual average effluent TSS concentration in mg/L
Lower bound:
Upper bound:
0
100
10. Months Effluent BOD5 Exceeds Permit Limit
The effluent BOD5 concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 BODS for secondary treatment) or on
a weekly basis (e.g., exceeds 7-day average of 45 mg/1 BOD5).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months that this facility has exceeded its
monthly BODS permit limte
Lower bound:
Upper bound:
0
12
-113-
-------
SCREEN
iV; f f^f % < \ i- iV.^
'QUEST|0%-Y';
ANSWER OPTIONS
11. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit Violations can occur on a monthly average basis (e.g.,
exceeds average 30 mg/1 TSS for secondary treatment) or on a
weekly basis (e.g., exceeds 7-day average of 45 mg/1 TSS).
Exceeding either of these conditions represents a violation for
that month.
Enter the number of months that this facility has exceeded Us
monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
12. Wasted Secondary Sludge Volume, gpd.
Sludge is typically wasted from the secondary clarifier(s) to
digestion or thickening facilities.
If the volume of wasted secondary sludge is not available,
attempt to estimate the total volume wasted from whatever
data are available. For example, if it is known approximately
how much time per day the secondary waste pumps are
operated, calculate the total volume from the capacity of the
waste pumps and operational tune.
If estimation is necessary, give the operator the benefit of the
doubt in any assumptions that have been made.
Enter the average daily volume of sludge wasted from the
secondary clarifier(s) for the previous twelve months, in gallons
per day.
Lower bound: 0
Upper bound: 5,000,000
-114-
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ANSWIIft OPTIONS
13. Wasted Secondary Sludge Concentration, mg/1. Lower bound: 0
Upper bound: 25,000
If no thickening unit processes are available, sludge is typically
wasted as thick as possible from the secondary clarifier. This
must be balanced with minimizing sludge detention time in the
clarifier(s) and associated detrimental effects (e.g.,
denitrification).
If the concentration of wasted secondary sludge is not
available, then enter 0 and POTW Expert will calculate a
concentration based upon typical sludge concentration for the
selected type of POTW.
Based on the following tables from the Retrofitting POTWs
manual:
Sludge Concentrations for Projecting Sludge
Production from Suspended Growth POTWs
Sludge Type Waste Cone., mgr/1
Primary 50,000
Activated
Return sludge/conventional 6,000
Return sludge/extended aeratioiT,500
Return sludge/contact
stabilization 8,000
Return sludge/small plant
with low SOR* 10,000
Separate waste hopper in
sec. clarifier 12,000
*Returns can often be shut off for short periods to thicken
waste sludge in clarifiers with SORs less than 20 m3/m2/d (500
gpd/sq ft).
-115-
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SCREEN
QUESTIONS
ANSWER OPTIONS
Unit Sludge Production and Sludge Concentration
Values for Projecting Sludge Production from
Fixed Film POTWs (1.21.26)
Process Type
Trickling filter
RBC
ABF
kg TSS (sludge)/
kg BOD; removed
0.9
1.0
1.0
Sludge Type
Primary
Primary -4- Trickling Filter
Primary + RBC
Primary + ABF
Trickling Filter
RBC
ABF
Waste Cone., mg/1)
50,000
35,000
35,000
30,000
20,000
20,000
10,000
Enter the average daily concentration of the waste secondary
sludge for the previous twelve months in mg/L If unknown, enter
0.
14. Wasted Sludge Concentration Reliability.
Do you consider concentration of the waste secondary sludge
to be a reliable value? One good indicator is whether the
operator checks the measurement at least once a day.
Indicate whether the waste secondary sludge concentration
measurement is considered reliable or unreliable.
Reliable
Unreliable
-116-
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ANSWER OWNS
15. Control of Sludge Wasting. . Automated sampling
andvolume control
Control of the sludge wasting process requires waste sludge Metered volume and hand
volume measurement and waste sludge sampling for sampling
determining concentration. Optimum control for a sludge Hand measured volume
wasting system includes automated volume control and andhand sampling
automated sampling. . Sampling or volume
'«,.,. measurement not available
Select the choice that best represents the waste sludge volume
measurement and sampling facilities at this plant.
How is the waste sludge volume measured and sampled?
-117-
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POTW EXPERT DATA ENTRY
AERATED POND FACILITY
&CREEW TEXT OU^tlONS
OPTIONS
1. Number of Ponds.
How many ponds are in this stabilization pond system?
How many ponds?
Lower bound:
Upper bound:
0
10
2. Number of Ponds in Series.
How many ponds are in series in the Current configuration of
this stabilization pond system?
How many ponds are in series?
Lower Bound:
Upper bound:
0
10
3. Parallel Flows.
Frequently, influent to stabilization pond systems may be split
between two series of ponds. If the ponds are operated in
parallel, POTW Expert will assume that each train receives
50% of the influent
If all ponds are operating in series, enter "No."
Are parallel flow routes used in the current configuration of this
stabilization pond system?
Yes
No
-118-
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$cfies*i ?ecr QUESTIONS
ANSWER OPTIONS
4. Diffused Air Aeration Ponds.
Aerated stabilization ponds may be either:
A Diffused Aeration System - air is introduced to the
wastewater through multiple air inlets in the basin, or
A Surface Mechanical Aeration System/Jet Aeration -
air is introduced through agitation of the water surface
by a mechanical mixer or air is introduced is a fine
bubble jet aerator.
How many ponds use diffused air systems?
Lower bound:
Upper bound:
0
10
5. Settling Ponds at End.
Frequently, aerated pond systems have one or more
non-aerated settling ponds at the end. POTW Expert does
not include non-aerated settling ponds in BOD5 and detention
time calculations.
How many settling ponds are in this POTW?
Lower bound:
Upper bound:
0
10
6. Total Energy Applied to Ponds.
Total energy applied to aerated poinds includes both aeration
and mixing energy.
What is the total energy applied to aerated ponds, in
horse-power?
Lower bound:
Upper bound:
0
999,999
7. Flexibility to Operate in Series or Parallel.
Does this POTW have the flexibility to operate with the
ponds either in series or in parallel?
Can this POTW operate in series or parallel?
Yes
No
-119-
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SCREEN TEXT QUESTIONS
OPTIONS
8. Variable Level Draw-Off Available.
Does this POTW have a variable level draw-off facility
available from the final pond?
Is variable level draw-off available?
Yes
No
9. Maximum Summer Wastewater Temp., °F.
The maximum wastewater temperature affects the oxygen
transfer capability of an aeration system because it affects
oxygen solubility. Maximum wastewater temperature will vary,
depending on geographic location, from 50°F to to 70°F (10°C
to 21°C).
What is the maximum summertime wastewater temperature, in
degrees Fahrenheit?
Lower bound:
Upper bound:
32
86
10. Maximum Summer Air Temperature, °F.
What is a typical maximum summer air inlet temperature?
What is the maximum summertime inlet temperature, in degrees
Fahrenheit?
11. Altitude above Mean Sea Level, ft.
Elevation affects performance of an aeration system, since the
saturation concentration of dissolved oxygen is lower at higher
altitudes.
Wtiat is the altitude of this facility above mean sea level, in
feet?
Lower bound:
Upper bound:
Lower bound:
Upper bound:
2
120
-120
10,000
-120-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
12. DO Testing.
Indicate how often dissolved oxygen is measured in the
"aerator." Select the frequency which is closest to plant's
actual testing routine.
If this test is not performed, select "Test not performed."
How often is the dissolved oxygen concentration measured in
the "aerated" unit?
3 times/week
2 times/day
3 times/day
Test not
performed
13. Effluent BOD5 Concentration, mg/1.
The effluent BOD5 concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent BOD5.
Enter the annual average effluent BODS concentration in mgll.
Lower bound:
Upper bound:
0
100
14. Effluent TSS Concentration, mg/1.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/1
effluent TSS.
Enter the annual averge effluent BODS concentration in mgll
Lower bound:
Upper bound:
0
100
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SCREEN TEXT QUESTIONS
/ft 'i
ANSWER OPTIQNS,
15. Months Effluent BODS Exceeds Permit Limit.
The effluent BOD5 concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 BOD5 for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average
of 45 mg/1 BODS) for typical secondary treatment. Exceeding
either of these conditions represents a violation for that
month.
Enter the number of months within the last year that this
facility has exceeded its monthly BOD $ permit limit.
Lower bound:
Upper bound:
0
12
16. Months Effluent TSS Exceeds Permit Limit.
The effluent TSS concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 TSS for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average
of 45 mg/1 TSS) for typical secondary treatment. Exceeding
either of these conditions represents a violation for that
month.
Enter the number of months within the last year that this
facility has exceeded its monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
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POTW EXPERT DATA ENTRY
FACULTATIVE POND FACILITY
QUESTIONS
ANSWER OPTIONS
1. Average Winter Temperature.
Which of the listed temperature ranges does the daily average
temperature from December through February fall into?
Choose the correct temperature range for the average winter
temperature.
Less than 32°F
Between 32°F and 599F
Greater than 59°F
2. Number of Ponds.
How many ponds are in this stabilization pond system?
How many ponds?
Lower bound:
Upper bound:
0
10
3. Number of Ponds in Series.
How many ponds are in series in the current configuration of
this stabilization pond system?
How many ponds are in series?
Lower bound:
Upper bound:
0
10
4. Parallel Flows.
Frequently, influent to stabilization pond systems may be split
between two series of ponds. If the ponds are operated in
parallel, POTW Expert will assume that each train receives
50% of the influent.
If all ponds are operating in series, enter "No."
Are parallel flow routes used in the current configuration of this
stabilization pond system?
Yes
No
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SCREEN TEXT QUESTIONS
"I?" ANSWER OPTIONS
5. Flexibility to Operate in Series or Parallel.
Does this POTW have the flexibility to operate with the
ponds either in series or in parallel?
Can this POTW operate in series or parallel?
Yes
No
6. Variable Level Draw-Off Available.
Does this POTW have a variable level draw-off facility
available from the final pond?
Is variable level draw-off available?
Yes
No
7. Effluent BODS Concentration, nag/1.
The effluent BOD5 concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/l
effluent BOD5.
Enter the annual average effluent BODS concentration in mg/l.
Lower bound:
Upper bound:
0
100
8. Effluent TSS Concentration, mg/l.
The effluent TSS concentration is typically regulated by the
National Pollutant Discharge Elimination System (NPDES)
permit. Typical secondary treatment requirements are 30 mg/l
effluent TSS.
Enter the annual averge effluent BODS concentration in mg/l.
Lower bound:
Upper bound:
0
100
-124-
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SCREEN TEXT QUESTIONS
ANSWER OPTION^
9. Months Effluent BOD5 Exceeds Permit Limit.
The effluent BOD5 concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 BOD5 for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average
of 45 mg/1 BOD5) for typical secondary treatment. Exceeding
either of these conditions represents a violation for that
month.
Enter the number of months within the last year that this
facility has exceeded its monthly BODs permit limit.
Lower bound:
Upper bound:
0
12
10. Months Effluent TSS Exceeds Permit Limit
The effluent TSS concentration is typically regulated by the
facility's National Pollutant Discharge Elimination System
(NPDES) permit. Violations can occur on a monthly average
basis (e.g., exceeds average 30 mg/1 TSS for secondary
treatment) or on a weekly basis (e.g., exceeds 7-day average
of 45 mg/l TSS) for typical secondary treatment. Exceeding
either of these conditions represents a violation for that
month.
Enter the number of months within the last year that this
facility has exceeded its monthly TSS permit limit.
Lower bound:
Upper bound:
0
12
-125-
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POTW EXPERT DATA ENTRY
STABILIZATION PONDS
SCREEN TEXT QUESTIONS
OPTIONS
1. Diffused Pond 1 Surface Area.
What is the surface area of this pond, in square feet?
What is the surface area, in square feet?
Lower bound: 1
Upper bound: 9,000,000
2. Diffused Pond 1 Average Depth.
What is the average depth of this pond, in feet?
What is the average depth, in feet?
Lower Bound:
Upper bound:
0
15
3. Diffused Pond 1 Distance from Inlet to Outlet
What is the distance between the wastewater inflow and the
point of effluent outflow, in feet, for this pond?
What is the distance between the wastewater inlet and the
effluent outlet, in feet?
Lower bound: 1
Upper bound: 3,000
4. Diffused Pond 1 Maximum Dimension.
What is the maximum dimension of the surface of the
stabilization pond, in feet?
What is the maximum dimension, in feet?
Lower bound: 1
Upper bound: 3,000
5. Diffused Pond 1 Minimum Dimension.
What is the minimum dimension of the surface of the
stabilization pond, in feet?
What is the minimum dimension, in feet?
Lower bound: 1
Upper bound: 3,000
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
6. Diffused Pond 1 Oxygen Transfer Cap., Ib O2/d.
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter
this value in terms of the maximum pounds of oxygen per day
that can be supplied. Firm capacity (i.e., capacity with one
blower out of service) should be considered when identifying
the available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the. oxygen transfer capacity, in Ib O2/day? If the
oxygen transfer capacity is not available, enter 0.
Lower bound:
Upper bound:
0
999,999
7. Diffused Pond 1 DO Concentration, mg/1.
What is the average dissolved oxygen level recorded in the
pond over the last 12 months, in mg/1?
What is the pond dissolved oxygen level, in mg/l?
Lower bound:
Upper bound:
0
10
8. Diffused Pond 1 Air Blower Capacity, cu fi/min.
What is the maximum capacity of the blowers? Give the
value of full firm capacity, i.e., the maximum capacity which
the blowers can supply with one blower out of service.
The ratings on blowers may be in terms of actual or inlet
cubic feet per minute (e.g., ACFM, ICFM).
What is the blower capacity, in ACFM or ICFM? Allow for
blower down-time (ie., assume that one blower is unavailable).
Lower bound:
Upper bound:
0
66,500
-127-
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
9. Diffused Pond 1 Type of Diffused Aeration System.
The types of aeration systems are:
Fine bubble diffusers with total coverage of the
aeration basin floor
Static aerators (medium-size bubble)
Coarse bubble diffusers in a wide band pattern
Coarse bubble diffusers in a narrow band pattern
Select the type of aeration system which best describes the
existing equipment, (See Help).
Fine bubble diffusers,
total floor coverage
Static aerators (medium-
size bubble)
Coarse bubble diffusers,
wide band pattern
Coarse bubble diffusers,
narrow band pattern
10. Mechanical Pond 1 Surface Area.
What is the surface area of this pond, in square feet?
What is the surface area, in square feet?
Lower bound: 0
Upper bound: 9,000,000
0
11. Mechanical Pond 1 Average Depth.
What is the average depth of this pond, in feet?
What is the average depth, in feet?
Lower bound:
Upper bound:
0
15
12. Mechanical Pond 1 Distance from Inlet to Outlet.
What is the distance between the wastewater inflow and the
point of effluent outflow, in feet, for this pond?
What is the distance between the wastewater inlet and the
effluent outlet, in feet?
Lower bound: 0
Upper bound: 3,000
-12S-
-------
ANSWER OPTIONS
13. Mechanical Pond 1 Maximum Dimension.
What is the maximum dimension of the surface of the
stabilization pond, in feet?
What is the maximum dimension, in feet?
« Lower bound: 0
Upper bound: 3,000
14. Mechanical Pond 1 Minimum Dimension.
What is the minimum dimension of the surface of the
stabilization pond, in feet?
What is the minimum dimension, in feet?
Lower bound: 0
Upper bound: 3,000
15. Mechanical Pond 1 Oxygen Transfer Cap., Ib O2/d.
Typically, plant design documents will list an oxygen transfer
capacity that the designer calculated for the facility. Enter
this value in terms of the maximum pounds of oxygen per day
that can be supplied. Firm capacity (i.e., capacity with one
blower out of service) should be considered when identifying
the available capacity.
If the oxygen transfer capacity is not available, enter 0.
What is the oxygen transfer capacity, in Ib O2/day? If the
oxygen transfer capacity is not available, enter 0.
Lower bound: 0
Upper bound: 50,000
16. Mechanical Pond 1 DO Concentration, mg/I.
What is the average dissolved oxygen level recorded in the
pond over the last 12 months, in mg/1?
What is the pond dissolved oxygen level, in mg/l?
Lower bound:
Upper bound:
0
10
-129-
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SCREEN TEXT QUESTIONS,
Itf&tofeft OPTIONS
17. Mechanical Pond 1 Pond Motors' Horsepower.
Typically, surface aerators in a POTW are driven by electrical
motors. Marked upon the casing of these motors, or in the
plant documentation, will be a rating of the mechanical
horsepower that the motor is capable of producing. The total
of the horsepower ratings for all of the motors is necessary to
determine the amount of energy available for adding oxygen
to the wastewater.
Wliat is the total rated mechanical horsepower of all of the
surface aerators?
Lower bound: 0
Upper bound: 1,400
18. Pond 1 Surface Area.
What is the surface area of this pond, in square feet?
What is the surface area, in square feet?
Lower bound:
Upper bound:
0
9,000,000
0
19. Pond 1 Average Depth.
What is the average depth of this pond, in feet?
What is the average depth, in feet?
Lower bound:
Upper bound:
0
15
20. Pond 1 Distance from Inlet to Outlet
What is the distance between the wastewater inflow and the
point of effluent outflow, in feet, for this pond?
What is the distance between the wastewater inlet and the
effluent outlet, in feet?
Lower bound: 0
Upper bound: 3,000
-130-
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AhfSWEft OFtlONS r
21. Pond 1 Maximum Dimension. Lower bound: 0
Upper bound: 3,000
What is the maximum dimension of the surface of the
stabilization pond, in feet?
What is the maximum dimension, in feet?
22. Pond 1 Minimum Dimension. Lower bound: 0
Upper bound: 3,000
What is the minimum dimension of the surface of the
stabilization pond, in feet?
What is the minimum dimension, in feet?
-131-
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POTW EXPERT DATA ENTRY
INDUSTRY CONTRIBUTORS
SCREEN TEXT QUESTIONS^, ,1^ ,^
" ; \ ' ".'. i\'.,^ - ",?*
1. Industry 1 Name.
You have indicated that one or more industries contribute
industrial wastes to the POTW. Enter the name of the
industry. If more than three industries exist, you may choose
to combine several industries so that all can be included.
For each industry that is entered into the system, you will be
asked to provide average daily flow, BOD5 concentration, and
TSS concentration data.
Enter the name of the industry that may be contributing
significant industrial wastes to the POTW.
Industry name
2. Industry 1 Average Daily Flow, gpd.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the average daily flow
contributed by the industry, in gallons per day.
Enter average daily flow of the industry, in gallons per day. If
unknown, enter 0.
Lower bound:
Upper bound:
0
1,000,000
3. Industry 1 BODS Concentration, mg/1.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
BOD5, in mg/1, that the industry contributes.
Enter the BOD$ contributed by the industry, in mg/L If
unknown, enter 0.
Lower bound:
Upper bound:
0
50,000
-132-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
4. Industry 1 TSS Concentration, mg/1.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
TSS, in mg/1, that the industry contributes.
Enter the TSS contributed by the industry, in mg/L If unknown,
enter 0.
* Lower bound: 0
Upper bound: 50,000
5. Industry 2 Name.
You have indicated that one or more industries contributes
industrial wastes to the POTW. Enter the name of the
industry. If more than three industries exist, you may choose
to combine several industries so that all can be included.
For each industry that is entered into the system, you will be
asked to provide average daily flow, BOD5 concentration, and
TSS concentration data.
Enter the name of the industry that may be contributing
significant industrial wastes to the POTW.
Industry name
6. Industry 2 Average Daily Flow, gpd.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the average daily flow
contributed by the industry, in gallons per day.
Enter average daily flow of the industry, in gallons per day. If
unknown, enter 0.
Lower bound:
Upper bound:
0
1,000,000
-133-
-------
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
7. Industry 2 BODS Concentration, mg/1.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
BOD5, in mg/1, that the industry contributes.
Enter the BOD5 contributed by the industry, in mg/l. If
unknown, enter 0.
Lower bound:
Upper bound:
0
50,000
8. Industry 2 TSS Concentration, mg/1.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
TSS, in mg/1, that the industry contributes.
Enter the TSS contributed by the industry, in mg/l. If unknown,
enter 0.
Lower bound:
Upper bound:
0
50,000
9. Septage Contributors Average Daily Flow, gpd.
You have indicated that there is an identifiable contributor of
industrial loading to the plant Enter the average daily flow
contributed by the industry, in gallons per day.
Enter average daily flow of the industry, in gallons per day. If
unknown, enter 0.
Lower bound: 0
Upper bound: 1,000,000
10. Septage Contributors BODS Concentration, mg/l.
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
BOD5, in mg/l, that the industry contributes.
Enter the BODS contributed by the industry, in mg/l. If
unknown, enter 0.
Lower bound:
Upper bound:
0
50,000
-134-
-------
ANSWER OPTIONS
11. Septage Contributors TSS Concentration, mg/1. Lower bound: 0
v .....,' Upper bound: 50,000
You have indicated that there is an identifiable contributor of
industrial loading to the plant. Enter the concentration of
TSS, in mg/1, that the industry contributes.
Enter the TSS contributed by the industry, in mg/l. If unknown,
enter 0.
-135-
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POTW EXPERT DATA ENTRY
PERFORMANCE-LIMITING FACTORS (PLFs)
SCREEN TEXT OUESTIONS
ANSWER OPTIONS
1. Full-Time or Part-Time Plant Coverage.
Plant coverage may influence plant operation's and
performance. Indicate whether the plant is staffed on a
24-hour basis or on a part-time basis.
Is plant staff on site on a full-time (24-hour) basis or on a
part-time (less than 24-hour) basis?
Full-time
Part-time
2. Staff Time on the Job.
Indicate the length of time that the plant supervisor and/or
key staff have been with this POTW. If key operating staff
are new to the facility, this may moderate the citing of
operational factors.
How long has the supervisor (or key staff) been operating
this POTW?
0-3 months
3 to 6 months
6 to 12 months
Greater than 1 year
Unknown
3. Plant Accessibility during All Seasons.
Certain plants may be difficult to access during certain parts of
the year (e.g., winter) for chemical or equipment delivery or
for routine operation.
Is the plant accessible during all seasons?
Yes
No
-136-
-------
4. Outside Sources for Technical Guidance. Yes
No
Are sources external to the plant (e.g., design engineer,
equipment representative, state trainer or inspector) influential
in directing the process control of this facility?
Are sources external to the plant influential in directing the
process control of this facility?
5. Short-Term Performance Changes. Yes
' No
Organism die-offe often indicate a toxic substance may be
entering the treatment processes.
In the past 12 months, has the facility experienced any MAJOR
short-term organism die-off that has led to degraded
performance?
6. Influent Color Change. Yes
No
In the past 12 months, has the plant operator observed any
notable changes in the color of the influent?
In the past 12 months, has the plant operator observed any
notable changes in the color of the influent?
7. Notable pH Changes. . Yes
» . No
During the past 12 months, has the plant experienced any
notable changes in pH levels of the influent?
During the past 12 months, has the plant experienced any
notable changes in pH levels of the influent?
-137-
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SCREEN TEXT QUESfidNS ""' ANSWER OPTIONS
8. Grit Problem. Yes
No
Often, plant operators will routinely claim a grit problem is
one of the root causes of performance problems. Do not
assume performance problems are due to grit problems unless
the operator can produce evidence of accumulated grit
interfering with the plant's capabilities.
Has a problem with excessive grit been observed or reported,
to the point that performance has been affected (e.g.,
accumulations in clarifiers, digesters, or aeration basins)?
Does a problem with excessive grit east?
9. Rag Problem. Yes
« No
Has a problem with excessive rag build-up been observed or
reported (e.g., pump plugging or build-up on surface
mechanical aerators)?
Does a problem with excessive rag build-up exist?
10. Plant Flow Totalizer. Yes
No
Ideally a plant should have a primary flow measuring device
that is combined with a sensor and a flow recording and
totalizer device. If calibrated, this provides reliable
information on plant hydraulic loadings.
Does this plant have a flow totalizer?
-138-
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SCREEN Tea QUESTIONS
ANSWER OPTIONS
11. Fecal Coliform Permit Requirement.
TTie federal government has initiated a national program for
permitting discharges from wastewater treatment facilities.
Fecal coliform bacteria is often one of the regulated
parameters. Violations can occur on a monthly average basis
(e.g., exceeds average 200 colonies per 100 ml) or on a weekly
basis (e.g., exceeds 400 colonies per 100 ml). Exceeding either
of these conditions represents a violation for that month.
Indicate the number of months that the fecal coliform
concentration exceeded its permit during a quarterly period.
For this evaluation, select the worst season or the four month
period when disinfection is required.
Indicate the number of months that this facility has exceeded its
fecal coliform permit limit. If there is no permit limit, enter 0.
Lower bound:
Upper bound:
0
4
12. Chlorine Residual Requirement.
The federal government has initiated a national program for
permitting discharges from wastewater treatment facilities.
Chlorine residual is the process most commonly used for
wastewater disinfection in the United States. POTWs using
this method must maintain chlorine residuals less a specified
maximum value. Indicate the number of months that the
chlorine residual exceeds permit value during a quarterly
period. For this evaluation, select the worst season or the
four month period when disinfection is required.
Indicate the number of months that this facility has exceeded its
chlorine residual permit limt If there is no permit limit, enter 0.
Lower bound:
Upper bound:
0
4
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SCREEN TEXT QUESTIONS , ANSWER OPTIONS
13. O&M Manual/Procedures - Use. Yes
No
A good O&M manual/procedures NOT used by the operator,
may cause poor process control and poor treatment that could
have been avoided.
Does poor process control and poor treatment result from the
misuse or non-use of the O&M manual/procedure document?
14. O&M Manual/Procedures - Adequacy. Yes
No
The O&M manual should address the following areas;
- Unit Process Functions,
- Process Control Testing,
- Data Development,
- Interpretation and Implementation
as they pertain to DO, Return Sludge Adjustments, mass
control, and activated sludge mode flexibility.
Does inappropriate guidance provided by the O&M
manual/procedures result in poor or improper operational
decisions?
-140-
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POTW EXPERT DATA ENTRY
PROCESS CONTROL TEST
SCREEN
QUESTIONS
OPTIONS
1. Secondary Clarifier Sludge Depth Testing.
Indicate how often the depth of sludge in the secondary
clarifier(s) is measured. Select the frequency which is closest
to the plant's actual testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
sludge depth, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2- 10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the sludge depth in the secondary clarifier
measured?
« 3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
-141-
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SCREEN TEXT QUESTIONS
OPTIONS
2. DO Testing.
Indicate how often dissolved oxygen is measured in the
"aerator." Select the frequency which is closest to the plant's
actual testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
dissolved oxygen level, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the dissolved oxygen concentration measured in the
"aerator"?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
-142-
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ANSWER OPTIONS
3. Mass Control Testing.
Mass control is accomplished by suspended solids testing and
centrifuge testing. Indicate how often mass control tests are
performed. Select the frequency closest to the plant's actual
testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to perform mass
control tests, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2-
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often are mass control tests performed?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
4. RAS Flow Control Monitoring.
Is the return activated sludge flow rate monitored and
recorded daily? If the flow rate is routinely monitored, does
the operators) use the recorded data to adjust the flow?
If the facility does not have the capability to monitor the
return activated sludge flow, answer "Not able to perform
test."
Is the return activated sludge flow rate routinely monitored and
adjusted?
Flow not monitored
daily
Flow monitored daily
but not adjusted daily
Flow monitored and
adjusted daily
Not able to perform test
-143-
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SCREEN TEXT QUESTIONS;
ANSWEtt OPTIONS
5. Settling Tests.
Settling tests such as determination of the sludge volume index
or the settled sludge concentration utilizing a settleometer are
appropriate. Indicate how often the settling tests are
performed. Select the frequency which is closest to the plant's
actual testing routine.
If this test is not performed, select "Test available but not
performed."
If the facility lacks the capability to perform settling tests,
answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often are settling tests performed?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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scReertfekt OUESTIONS
AHSWEfc OPTIONS
6. Microscopic Examination.
When the type of plant is Suspended Growth orABF
Microscopic examinations can be used to assess sludge
characteristics. Indicate how often the microscopic
examinations are performed. Select the frequency closest to
the plant's actual testing routine.
If this test is not performed, select "Test available but not
performed," If the facility lacks the capability to perform
microscopic examinations, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
< 2
2- 10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often are microscopic examinations performed?
3 times/week
2 times/day
3 times/day
Test available but not
performed
* Not able to perform test
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SCREEN TEXT QUESTIONS
6. Microscopic Examination (cont).
When the Type of Plant is Stabilization Pond
Microscopic examinations can be used to assess sludge
characteristics. Indicate how often the microscopic
examinations are performed. Select the frequency closest to
the plant's actual testing routine.
If the test is not performed, select "Test available but not
performed." If the facility lacks the capability to perform
microscopic examinations, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
1 time/week
2 times/week
3 times/week
These are considered to be the minimum advisable
frequencies.
How often are microscopic examinations performed?
1 time/week
2 times/week
3 times/week
Only when the plant has
problems
Test available but not
performed
Not able to perform test
7. Recirculation Control Monitoring.
Is the wastewater recirculation rate monitored and recorded
daily? If the flow rate is routinely monitored, does the
operator(s) use the recorded data to adjust the flow?
If the facility does not have the capability to monitor
recirculation flow, answer "Not able to perform test."
Is the wastewater recirculation rate routinely monitored and
adjusted?
Flow not monitored
daily
Flow monitored daily
but not adjusted daily
Flow monitored and
adjusted daily
Not able to perform test
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SCREEN f£>Cf QUESTIONS ANSWER OPTIONS
8. Observation of Growth on Media. 3 times/week
2 times/day
Indicate how often the media of the plant is checked for 3 times/day
excess growth. Select the frequency which is closest to the Test available but not
plant's actual testing routine. performed
If the test is not performed, select "Test available but not
performed."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the growth on the media checked?
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SCREEN TEXT QUESTIONS ,
ANSWEK pPTtONS
9. Food to Microorganism Ratio Test
Indicate how often the food to microorganism ratio is
measured. Select the frequency which is closest to the plant's
actual testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
food to microorganism ratio, answer "Not able to perform
test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
ffigd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the food to microorganism ratio measured?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
10. Mean Cell Residence Time Test
Indicate how often the mean cell residence time is measured.
Select the frequency which is closest to the plant's actual
testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
mean cell residence time, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the mean cell residence time measured?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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SCREEN TEXT QUESTIONS
\ i ^..K^
*X3y *
SUES
INSWEM OPTIONS
11. Sludge Residence Time Test
Indicate how often the sludge residence time is measured.
Select the frequency which is closest to the plant's actual
testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
sludge residence time, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the sludge residence time measured?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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f s*,v,. f < .", ^ % '
SCREEN TEXT QUESTIONS
ANSWER OPTIONS
12. Total System Mass Test
Indicate how often the total system mass is measured. Select
the frequency which is closest to the plant's actual testing
routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
total system mass, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the total system mass measured?
3 times/week .
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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SCREEN
QUESTIONS
ANSWER OPTIONS
13. Sludge Wasting Volume Test.
Indicate how often the sludge wasting volume is measured.
Select the frequency which is closest to the plant's actual
testing routine.
If this test is not performed, select "Test available but not
performed." If the facility lacks the capability to measure the
wasting volume, answer "Not able to perform test."
Frequency of tests is assessed based on plant size according to
the following schedule:
Plant Size
Small
Medium
Large
mgd
<2
2-10
> 10
Frequency
of Tests
3 times/week
2 times/day
3 times/day
These are considered to be the minimum advisable
frequencies.
How often is the sludge wasting volume measured?
3 times/week
2 times/day
3 times/day
Test available but not
performed
Not able to perform test
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POTW EXPERT DATA ENTRY
FOLLOW-UP QUESTIONS FOR
PROCESS CONTROL TESTING
scfiEEW tecr QUESTIONS
ANSWER OPTIONS
1. Lack of Secondary Clarifier Sludge Depth Testing.
Is the inability to measure the depth of the secondary clarifier
sludge due to a lack of administrative support-in the form of
insufficient funding, bad policies, etc.? Or is the inability due
to a lack of importance being placed upon the measurement
by the operator?
Is the inability to measure the depth of the secondary clarifier
sludge due to administrative or operational problems?
Administrative problem
Operational problem
2. Lack of DO Testing.
Is the inability to measure the dissolved oxygen level due to a
lack of administrative support-in the form of insufficient
funding, bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the dissolved oxygen level due to
administrative or operational problems?
Administrative problem
Operational problem
3. Lack of Mass Control Testing.
Is the inability to perform mass control testing due to a lack of
administrative support-in the form of insufficient funding, bad
policies, etc.? Or is the inability due to a lack of importance
being placed upon the test by the operator?
Is the inability to test the mass control aspects of the plant due
to administrative or operational problems?
Administrative problem
Operational problem
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SCREEN TEXT QUESTIONS
.-:.::;; \ - .,,,
ANSWER OPTIONS
4. Correlation of Mass Control Test Results.
Are the results of suspended solids tests and centrifuge tests
correlated on a weekly basis? This procedure verifies the
results of centrifuge testing.
Are suspended solids tests correlated with centrifuge tests on a
weekly basis?
Correlated
Not correlated
5. Lack of RAS Flow Control Monitoring.
Is the inability to monitor the return activated sludge flow rate
due to a lack of administrative supportin the form of
insufficient funding, bad policies, etc.? Is the inability due to
a lack of importance being placed upon the measurement by
the operator? Or, does the problem arise from a design
deficiency making it impossible to accurately measure RAS
flow?
Is the inability to monitor the RAS flow rate due to
administrative, operational or design problems?
Administrative problem
Operational problem
Design problem
6. Lack of Settling Tests.
Is the inability to perform settling tests due to a lack of
administrative support-in the form of insufficient funding, bad
policies, etc.? Or is the inability due to lack of importance
being placed upon the test by the operator?
Is the inability to perform the settling tests due to administrative
or operational problems?
Administrative problem
Operational problem
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SCREEN teCT QUESTIONS
ANSWER OPTIONS
7. Lack of Microscopic Examination.
Is the inability to perform microscopic examinations due to a
lack of administrative support-in the form of insufficient
funding, bad policies, etc.? Or is the inability due to lack of
importance being placed upon the test by the operator?
Is the inability to perform the microscopic examinations of the
plant due to administrative or operational problems?
Administrative problem
Operational problem
8. Lack of Recirculation Control Monitoring.
Is the inability to monitor the recirculation rate due to a lack
of administrative support-in the form of insufficient funding,
bad policies, etc.? Or is the inability due to lack of
importance being placed upon the measurement by the
operator? Or, does the problem arise from a design deficiency
making it impossible to accurately measure recirculation?
Is the inability to monitor the recirculation level due to
administrative, operational or design problems?
Administrative problem
Operational problem
Design problem
9, Lack of Food to Microorganism Ratio Testing.
Is the inability to measure the food to microorganism ratio due
to a lack of administrative support-in the form of insufficient
funding, bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the food to microorganism ratio due
to administrative or operational problems?
Administrative problem
Operational problem
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
10. Lack of Mean Cell Residence Time Testing.
Is the inability to measure the mean cell residence time due to
a lack of administrative support-in the form of insufficient
funding, bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the mean cell residence time due to
administrative or operational problems?
Administrative problem
Operational problem
11. Lack of Sludge Residence Time Testing.
Is the inability to measure the sludge residence time due to a
lack of administrative supportin the form of insufficient
funding, bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the sludge residence time due to
administrative or operational problems?
Administrative problem
Operational problem
12. Lack of Total System Mass Testing.
Is the inability to measure the total system mass due to a lack
of administrative support-in the form of insufficient funding,
bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the total system mass due to
administrative or operational problems?
Administrative problem
Operational problem
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SCftEENfiDfr QUESTION^ _- .ANSWER OPTIONS
13. Lack of Sludge Wasting Volume Testing. . Administrative problem
Operational problem
Is the inability to measure the sludge wasting volume due to a
lack of administrative support-in the form of insufficient
funding, bad policies, etc.? Or is the inability due to a lack of
importance being placed upon the measurement by the
operator?
Is the inability to measure the sludge wasting volume due to
administrative or operational problems?
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CHAPTER 4
SLUDGE HANDLING CONFIGURATION
AND DATA ENTRY
4.0 INTRODUCTION
This chapter describes the POTW Expert Sludge Handling Configuration module that evaluates a
POTW's sludge handling system. This module allows the user to create a graphic representation of
the sludge handling system being analyzed. The Sludge Handling Configuration screen is followed
by a SLUDGE HANDLING data entry form, which POTW Expert tailors to match the configuration
that has been entered. The system is designed to accept the most common sludge handling
configurations.
4.1 CREATING A SLUDGE HANDLING CONFIGURATION
4.1.1 Starting a Configuration Screen
The Sludge Handling Configuration input process is contained on one screen. A configuration is
created on the screen using function keys to add sludge, handling units (e.g; aerobic digester,
mechanical dewatering, etc.) and links between the subunits that represent the flow of sludge. When
the module begins, the sludge source(s) (secondary clarifier and/or primary clarifier) appear in the
lower left corner of the screen. A configuration can begin with either of these source units. After
you add the first linked subunit, the configuration moves to the upper left corner of the screen and
the rest of the configuration develops across the top of the screen to the right (as seen in Figure 4-1).
4.1.2 Adding Sludge Handling Units and Links
Sludge handling units and the links between them are added using active function keys. These keys
and the commands they execute (see below) are listed at the bottom of the screen in a command line.
Sludge handling subunits are represented on the screen as white boxes containing the unit label.
Links are the lines between subunits. At any one time, there is one subunit that is considered
"active," and is displayed in inverse video (white letters on black). Mechanical Dewatering is the
active subunit in Figure 4-1. Any of the subunits on the screen can be chosen, or "activated," using
arrow keys to move the current subunit selection from box to box. The active unit is the subunit
from which an adjacent link or subunit can be added or deleted.
The active subunit in Figure 4-1 is Mechanical Dewatering. As depicted, added or deleted links or
subunits must be connected to this subunit. To add or delete a link or subunit that is not connected
to Mechanical Dewatering, select a different subunit as active. For instance, to add a link between
the Secondary Sludge and Gravity Thickener subunits, use the left arrow key to move the black
highlighted box through the configuration to activate either of the subunits to be connected. Press
F2: Add to call the Add a Link Command. Commands are described in detail below.
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Link
Initial sludge'
source subunits
Second Gravity
Thickening subunit
Command line ->
Sludge Handling Configuration
First Gravity
Thickener subunit
Active subunit,
displayed in
inverse video
F1: Help F2: Add F4: Delete F5: Next Form F7: Quit System
F2: Add
pop-up menu
<- from which the
next command
is selected
Figure 4-1. Sludge Handling Configuration sample screen.
Links can be added or deleted at any time during the creation of the configuration. POTW Expert
provides a menu from which to choose the subunit that is to be joined in the active subunit. If
necessary, the system also asks which direction sludge will flow through the link, to or from the active
subunit. Both of these questions, and any other required information, will be asked through pop-up
menus. Options are selected and entered using the arrow keys and ENTER. When a subunit or link
is added to a configuration, POTW Expert automatically reconfigures the display to avoid any crossing
links.
(NOTE; As each subunit/link is added, POTW Expert checks the configuration. Links that
create a circular, or cycling sludge path loop are not allowed. Also, if the user
attempts to move to a non-existent box, there is a beep. This does not threaten the
system, but rather alerts the user to the incorrect move.)
4.2 SLUDGE HANDLING CONFIGURATION COMMAND LINE
The Sludge Handling Configuration Module has its own unique set of command line function keys.
As with the command line on the POTW Expert data entry forms, the function keys execute
commands or call menus. The active function keys are listed below in the left column. On the right
are the menu options these keys call to the screen and explanations of these options.
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F1: Help Calls the POTW Expert Help Screen.
F2: Add Calls a two-option pop-up menu to the screen that allows you to Add a
Subunit or Add a Link from the active subunit.
Add a Subunit: Presents a menu of possible sludge handling subunits. The
subunits are selected and entered using the arrow keys and ENTER. POTW
Expert is designed to allow the most common types of sludge handling
configurations. The list of possible subunits includes all options that will
continue the sludge path in a logical direction, generally, from source to
processing to disposal. Acceptable subunits are listed below. The column on
the right shows the abbreviations that represent these units on the screen.
Sludge Units Equivalents
Drying Bed Same
Mechanical Dewatering Mech. Dewater
Aerobic Digester Same
Anaerobic Digester Anaerob. Digester
Dissolved Air Floatation DAF '.'"''
Gravity Thickener Gravity Thick.
Hauling Same
Land Application Land App.
Other Same
In addition, when a sludge treatment process is added to the sludge handling
configuration, the system automatically assigns that unit a name for reference
during related questioning. For example, a Mechanical Dewatering process
is named MechanicalDewatering, or a Dissolved Air Flotation process is
named Dissolved Air Flotation.
(NOTE; As in Figure 4-1, if a configuration contains two of the same type of unit, POTW
Expert numbers them sequentially (e.g. Gravity Thickl, Gravity Thick2). If the user
deletes the first occurrence of a unit, all "downstream" units of the same type will be
renumbered.)
Add a Link: This command adds a link between the active subunit and
another subunit. The system asks if the added link will represent a flow of
material to or from the active subunit. A list of subunits is then provided
from which the user chooses the subunit that is to be linked. The active
subunit is then linked to the chosen subunit in the appropriate sequence.
F4: Delete Calls a two-option menu to the screen that allows you to Delete a Subunit or
Delete a Link from the active subunit.
Delete a Subunit: The active subunit is deleted using this command.
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Delete a Link: Any of the links connected to the active subunit are selected
and deleted using this command.
F5: Next Screen Proceeds directly to the next data entry following confirmation.
F7: Quit Calls the Exit Menu that includes the Exit System option. There is no save
feature within this menu.
Exit System: Leaves the Sludge Handling Module and ends the current
POTW Expert session.
4.3 LEAVING THE SLUDGE HANDLING CONFIGURATION
When the sludge handling configuration on the screen resembles the plant being evaluated, press F5:
Next Form to proceed to the next data entry form. POTW Expert will then ask a series of questions
relevant to the sludge handling configuration that has just been created. The user will only be able
to exit the sludge configuration module after a sludge path is adequately configured. Specifically, all
sources (secondary, primary sludge, and cosettled) must flow to at least one sludge subunit.
4.4 SLUDGE DATA ENTRY
After the sludge handling configuration has been entered, POTW Expert requests data in a Sludge
Handling Data Entry Form. The questions and answer options are listed below.
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POTW EXPERT DATA ENTRY
SLUDGE COMPONENTS
-
ANSWER OPTIONS,
1. Anaerobic Digester Mode.
Does the Anaerobic Digester operate in a single-stage mode
(e.g., one unit prior to the next downstream sludge treatment
unit) or a two-stage mode (e.g., two digestion units operated
in a series)?
Single Stage or Two Stage?
Single stage
Two stage
2. Anaerobic Digester Volume, gal.
What is the volume of the Anaerobic Digester, in gallons?
For a two-stage operation, include the volume of both stages.
What is the volume of this sludge unit, in gallons?
Lower bound:
Upper bound:
0
20,000,000
3. Mechanical Dewatering Unit Type.
What type of dewaterer is the unit, Mechanical Dewatering?
Select a type of mechanical dewaterer.
Belt press
Centrifuge
Other
4. Mechanical Dewatering Units, Number.
How many units named Mechanical Dewatering exist?
How many units does this mechanical dewaterer contain?
Lower bound:
Upper bound:
1
20
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
5. Mechanical Dewatering Operating Time, hr.
How many hours per week, on the average, is Mechanical
Dewatering operated?
Enter the average hours each unit is operated, per week.
Lower bound:
Upper bound:
0
168
6. Mechanical Dewatering Treatment Rate, units.
Dewatering units are typically rated for certain loadings by the
manufacturer. This information should be available in the
manufacturer's literature or plant manual.
There are various possible units of measurement for the
design application rate. Choose the appropriate description
for the application rate for the Mechanical Dewatering unit.
Choose the appropriate description of the application rate for
the Mechanical Dewatering unit(s).
Ib/hr
gal/min
unknown
7. Mechanical Dewatering Treatment Rate (see Help).
By design, what application rate can Mechanical Dewatering
sustain, in Ib/hr or gal/min?
You should check to see if the operators have records showing
observed treatment rates. If these records appear to be
representative of actual capability, use them rather than the
design rates.
What is the design treatment rate, in Ib/hr or gal/min?
Lower bound:
Upper bound:
0
100,000
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,.,
SCREfeN TEXT QUESTIONS
, . ,
AtfSWEft OPTIONS
f f * C. *»+ Ji 'i'i f"f
8. Mechanical Dewatering Capture Percentage.
Enter the capture percentage for this mechanical dewaterer.
If unknown, enter 0. E the capture percentage is unknown,
the system will default to a 90% capture rate.
(NOTE; The default capture percentage assumes operational
observation and control to maintain a 9Q% capture rate.)
Enter the capture percentage for this mechanical dewaterer. If
unknown, enter 0.
Lower bound:
Upper bound:
0
100
9. Mechanical Dewatering Output Concentration, %.
What concentration in percent solids by weight does
Mechanical Dewatering produce in its output sludge?
If unknown, enter 0.
What is the output concentration, in percent solids by weight? If
unknown, enter 0.
Lower bound:
Upper bound:
0
35
10. Polymers Used in Mechanical Dewatering.
Does the sludge treatment unit Mechanical Dewatering make
use of polymers to enhance its performance?
Are polymers used with this sludge treatment unit to enhance its
performance?
Polymers used
Polymers not used
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SCfiEEN Tea QUESTIONS
ANSWER OPTIONS
11. Hauling Distance, miles.
In the sludge unit named Hauling, what is the distance (one
way) to the sludge disposal site?
What is the average distance that sludge is hauled, in miles?
Lower bound:
Upper bound:
0
100
12. Hauling Truck(s) Volume, units.
The capacity of sludge hauling trucks can be measured in two
different units, depending upon the concentration of sludge
hauled. If the sludge being hauled is almost solid (greater
than 50% concentration), then the volume of the truck used is
usually measured in cubic yards. If the sludge is liquid (less
than 50% concentration), hauling trucks have tanks with
volume measured in gallons.
Choose the appropriate volume units for Hauling.
Gallons
Cubic yards
13. Hauling Total Truck(s) Volume, units.
What is the total volume of the sludge unit Hauling?
Enter the total volume of the sludge hauling truck(s). If
certain constraints prevent all of the trucks from being on the
road at the same time, enter the total volume of the average
number of trucks on the road at any given time.
What is the total volume of the sludge hauling truck(s), in cubic
yards or gallons?
Lower bound:
Upper bound:
0
20,000
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SCREEN
QUESTIONS
ANSWER OPTIONS
14. Aerobic Digester Volume, gal.
What is the volume of the sludge unit Aerobic Digester, in
gallons?
What is volume of this sludge unit, in gallons?
Lower bound: 0
Upper bound: 20,000,000
15. Drying Beds Volume, gal.
What is the volume of the Drying Beds, in gallons?
When determining the volume of drying beds, use the full
available depth rather than a typical operating depth of 9
inches. POTW Expert will use the total available volume for
determining bed capacity even though this may not represent
optimum depth for sludge drying.
What is the volume of this sludge unit, in gallons?
Lower bound: 0
Upper bound: 20,000,000
16. Drying Beds Worst Turnover Time, days.
What is the worst turnover time for the sludge to be applied
and then removed from the Drying Beds, in a given year (in
days)?
For example, some POTWs may experience seasonal freezing
temperatures during which period no removal from the drying
beds occurs.
Enter the greatest number of consecutive days during which
no sludge removal from the drying bed occurs.
What is the worst turnover time, in days?
Lower bound:
Upper bound:
0
365
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
17. Dissolved Air Flotation Operating Time, he.
How many hours per week, on the average, is the Dissolved
Air Flotation in operation?
Enter the average number of hours of operation, per week.
Lower bound:
Upper bound:
0
168
18. Dissolved Air Flotation Sludge Loading Rate.
Is sludge applied to the Dissolved Air Flotation at a constant
rate or is the loading variable throughout the day (e.g., pumps
on and then off rather than on at a constant rate).
Is the sludge loading method to this sludge unit variable or
constant?
Variable
Constant
19. Dissolved Air Flotation Surface Area, sq ft
What is the surface area of the dissolved air flotation unit(s),
named Dissolved Air Flotation, in square feet?
What is the surface area of this Dissolved Air Flotation unit, in
square feet?
Lower bound: 0
Upper bound: 30,000
20. Gravity Thickener Operating Time, hr.
How many hours per week, on the average, is the Gravity
Thickener in operation?
Enter the average number of hours of operation per week.
Lower bound:
Upper bound:
0
168
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;scfttsiENISXTtfiMstioNts; - - - Atiswe*OPTIONS
21. Gravity Thickener Sludge Loading Rate. Variable
Constant
Is sludge applied to the Gravity Thickener at a constant rate
or does the loading vary throughout the day (e.g., pumps on
and then off rather than on at a constant rate)?
Is the sludge loading method to this sludge unit variable or
constant?
22. Gravity Thickener Surface Area, sq ft Lower bound: 0
Upper bound: 30,000
What is the total surface area of the gravity thickener named
Gravity Thickener, in square feet?
What is the total surface area of this gravity thickener, in square
feet?
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SCREEN TEXT QUESTIONS
ANSWEfc OPTIONS
ADDITIONAL QUESTIONS
(NOTE: The following variables appear individually as POTW
Expert needs the information. Each variable attempts to give
the given sludge unit a higher potential projected capacity.
The variables are only asked until the potential projected
capacity is increased to a minimum acceptable level.)
Al. Increase Operating Time of MechanicalDewatering.
You have indicated that the MechanicalDewatering unit has
an average weekly manned time of hours.
The current estimated load to this unit appears excessive. It
may be possible to process more sludge by increasing the
hours of operation for this unit.
Enter the new TOTAL average weekly manned time
( + additional hours).
If it is not possible to increase the manned hours, enter 0.
What is the maximum average manned time per week possible
for this sludge unit, in hours?
Lower bound:
Upper bound:
0
168
A2. New Sludge Truck.
Can this POTW arrange additional disposal options (e.g.
purchase/lease additional trucks) to provide sufficient capacity
for hauling sludge to a disposal site?
Can the POTW arrange additional disposal options for hauling
sludge?
Yes
No
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SCREEN TEXT QUESTIONS
ANSWER OPTIONS
A3. Increase Operating Time of DissolvedAirFloatation.
You have indicated that the DissolvedAirFloatation unit has
an average weekly manned time of hours.
The current estimated load to this unit appears excessive. It
may be possible to process more sludge by increasing the
hours of operation for this unit.
Enter the new TOTAL average weekly manned time
( + additional hours).
If it is not possible to increase the manned hours enter 0.
What is the maximum average manned time per week possible
for this sludge unit, in hours?
Lower bound:
Upper bound:
0
168
A4. DissolvedAirFloatation Sludge Loading Rate Adjustable.
Frequently, the sludge loading method to the
DissolvedAirFloatation unit can be adjusted to operate in
either constant or variable loading.
Can the sludge loading method to this unit operate in either
constant or variable loading?
Yes
No
AS. Polymers Available In DissolvedAirFloatatiop..
Is the sludge treatment unit DissclvedAirFloatation equipped
to use polymers in its treatment process?
Does this sludge treatment unit have the necessary equipment to
use polymers in its treatment process?
8 Can use polymers
Cannot use polymers
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ANSWER OPTIONS
A6. Polymers Used In DissolvedAirFloatation.
Does the sludge treatment unit DissolvedAirFloatation make
use of polymers to enhance its performance?
Arepofymers used with this sludge treatment unit to enhance its
performance?
Polymers used
Polymers not used
A7. Increase Operating Time of GravityThickener.
You have indicated that the GravityThickener unit has an
average weekly manned time of hours.
The current estimated load to this unit appears excessive. It
may be possible to process more sludge by increasing the
hours of operation for this unit.
Enter the new TOTAL average weekly manned time
( + additional hours).
If it is not possible to increase the manned hours enter 0.
What is the maximum average manned time per week possible
for this sludge unit, in hours?
Lower bound:
Upper bound:
0
168
A8. GravityThickener Sludge Loading Rate Adjustable.
Frequently, the sludge loading method to the
GravityThickener unit can be adjusted to operate in either
constant or variable loading.
Can the sludge loading method to this unit operate in either
constant or variable loading?
Yes
No
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SCREEN TEXT QUESTIONS - " ANSWER OPTIONS
A9. Polymers Available In GravityThickener. Can use polymers
Cannot use polymers
Is the sludge treatment unit GravityThickener equipped to use
polymers in its treatment process?
Does this sludge treatment unit have the necessary equipment to
use polymers in its treatment process?
A10. Polymers Used In GravityThickener. Polymers used
Polymers not used
Does the sludge treatment unit GravityThickener make use of
polymers to enhance its performance?
Are polymers used with this sludge treatment unit to enhance its
performance?
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4.5 EVALUATION OF THE SLUDGE HANDLING PROCESS
After entering information pertaining to a plant's sludge configuration, POTW Expert assesses the
sludge handling processes to establish the Type (e.g., Type 1, 2, or 3) of this major unit process.
Each existing sludge handling process (treatment and disposal) is evaluated to determine the
percentage of the expected sludge production that each process can handle. This is referred to as
a processes "initial capacity".
If POTW Expert's initial evaluation establishes that a unit's initial capacity for handling the expected
sludge production is inadequate or marginal, the system will investigate alternative operating options.
These alternative options (e.g., increase operating time, the addition of polymers, etc.) may improve
a unit's capacity. The resulting improvement is referred to as a unit's potential projected capacity.
To conduct this investigation, the variables listed in the Additional Questions section of this chapter
may be asked so that POTW Expert can ascertain a unit's potential capacity.
4.6 EXPLANATION OF POTENTIAL PROJECTED CAPACITY
Potential Projected Capacity is determined by a sludge processes existing operating conditions (initial
capacity) plus any operational options that can be implemented to increase the initial capacity.
POTW Expert will upgrade a sludge handling processes Type from 3 to 2 (inadequate to marginal)
if potential projected capacity can be identified. The following descriptions may appear in the Sludge
Handling Section of the Major Unit Process Report.
(Note: POTW Expert's projected improvements are performance improvement guidelines. Actual
improvements in a sludge treatment processes capacity may vary at a particular plant. If necessary,
the evaluator should dampen (or magnify) the effect of the projected capacity based on information
outside the scope of POTW Expert's analysis.)
This section describes the effect of the improvement to a sludge processes projected capacity.
Increased operating time adds - This option increases a sludge processes' initial capacity
proportionately with an increase in operating time. For example, if the operating time of a
gravity thickener increases by 10 percent, potential projected capacity becomes the initial
projected capacity increased by 10 percent.
Increased waste sludge concentration adds - For sludge processes receiving secondary sludge,
this option increases a sludge processes' initial capacity by increasing the concentration of the
sludge from the secondary clarifier. Thickening sludge in the secondary clarifier increases the
sludge concentration to 10,000 mg/1. The initial capacity of any downstream sludge treatment
processes whose operation can be improved by increase sludge concentration will also benefit.
The use of polymers adds - This option increases a sludge processes' initial capacity with a
relative improvement of 25% as a result of polymer addition.
Constant influent feeding adds - For sludge processes that operate using a variable feeding
rate, but have the capability to operate in a constant feed mode, this option extends a sludge
processes' initial capacity by approximately 10%.
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A new sludge truck - If hauling is identified as inadequate and the analysis indicates that the
facility can arrange for additional disposal options (e.g., lease additional trucks). POTW
Expert assumes that the adequate disposal options will contribute sufficient volume to provide
100% capability.
Transfer of excess to hauling adds - If sludge drying beds are identified as inadequate and
excess hauling capacity exists, then POTW Expert will utilize the excess hauling capacity as
an alternative disposal option.
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CHAPTER 5
POTW EXPERT CONSULTATION AND REPORT GENERATION
5.0 INTRODUCTION
This chapter provides information on POTW Expert's CPE consultation, report generation, and
procedures that lead to the final identification of Potential Performance-Limiting Factors. The
consultation includes the following processing phases:
e Data Integrity Check
Major Unit Processes Evaluation
m Evaluation of Performance-Limiting Factors
Although this chapter presents all the information required to conduct a consultation it is
recommended that the EPA Handbook, Retrofitting POTWs be consulted for further information on
the evaluation procedures.
5.1 DATA INTEGRITY CHECK
POTW Expert conducts a data integrity check after specific information on plant characteristics and
loadings for the major unit processes have been input. The data integrity check validates plant
loading data with typical per capita contributions for domestic wastewater and compares other plant
characteristics with the projected values for a plant of similar characteristics. For example if a
primary clarifier exists, POTW Expert will calculate the percent removal of BOD5 in the primary
clanfier and determine whether it is within expected ranges for a primary clarifier with a given surface
overflow rate. The system then notifies the user of any discrepancies between the reported and
projected values. During the data integrity check, POTW Expert may display several screens of
information to which the user must respond.
5.2 MAJOR UNIT PROCESS EVALUATION
The Major Unit Process evaluation evaluates the major unit processes to assess their potential to
achieve desired performance levels. The major unit processes are evaluated in the following
sequence:
1. Aerator
2. Secondary Clarifier
3. Sludge Handling
NOTE: The term "Aerator" is used in this document and the expert system to
describe the unit process that provides the conversion of dissolved and suspended
organic matter to settleable microorganisms. Examples of aerators include aeration
basin, trickling filter, and rotating biological reactor.
A point system is used to quantify the evaluation of these three basic units. Consult the Handbook,
Retrofitting POTWs for parameters for scoring the unit processes.
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5.2.1 Major Unit Processes Report
POTW Expert generates the Major Unit Processes (MUP) Report as the first of three reports. For
each major unit process, the report summarize's the key loading and process parameters and assigns
points to the parameters. Subsequently, each of the three major unit processes receives a total score
by adding together the value of the points assigned the parameters. The totals are then compared
to standards to assess whether a Type 1, 2, or 3 capability is indicated for that unit process. The
overall plant type is determined by the "weakest link" among the three major unit process areas.
If the evaluation of major unit processes shows that the basic unit processes may have adequate
capacity (e.g., the POTW is a Type 1 or 2), then all performance-limiting factors are considered as
possible to correct with adequate training of the appropriate POTW personnel. The training is
addressed toward:
The operational staff for improvements in plant process control and maintenance
The POTW administration for improvements in administrative policies and budgets
limitations
Both operators and administrators to achieve minor facility modifications.
If the POTW is identified as having inadequate capacity (e.g., Type 3), however, then, although other
limiting factors may exist, such as the operators' process control capability or the administration's
unfamiliarity with plant needs, performance cannot be expected to improve significantly until physical
limitations of major unit processes are corrected.
5.3 EVALUATION OF PERFORMANCE-LIMITING FACTORS
The intent of the evaluation of performance-limiting factors is to clearly identify the factors that most
accurately describe the causes of poor performance. POTW Expert, the checklist of performance-
limiting factors in Appendix B, and the Handbook, Retrofitting POTWs provide the structure for
reviewing the factors.
In addition to the data required for the Major Unit Process Evaluation, POTW Expert requires
factor-related information. POTW Expert requests this information in two formats, the standard data
entry form (e.g., multiple question format) and single answer format (refer to Chapter 2.1), from
which the system evaluates the data and generates the Observation Report.
5.3.1 Observation Report
The observation report summarizes performance-related observations, highlights anomalies between
reported and expected data, and assists in further refining an evaluator's followup interview questions.
The Sludge Accountability Analysis is a particularly valuable aspect of this report and can provide
significant insight to the CPE effort. In general, the analysis indicates whether the plant effluent data
arc reliable indicators of true plant performance.
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5.3.2 Identification and Prioritization of Performance-Limiting Factors
In most POTW Expert consultations, several factors are identified as limiting performance This
section includes a summary of performance-limiting factors (PLFs), prioritization strategy and
classification systems.
Once PLFs have been identified, they are prioritized as to their adverse effect on achieving desired
plant performance. This prioritization establishes the sequence and/or emphasis of compliance. If
the highest ranking factors (i.e., those having the most negative impact on performance) are related
to physical limitations in unit process capacity, initial corrective actions should be directed toward
defining plant modifications and obtaining funding for their implementation.
The prioritization of factors is a twofold process. First, all factors that have been identified are
individually assessed with regard to adverse impact on plant performance and assigned an "A," "B"
or "C" rating. Factors can also receive a "NR" or No Rating. The table below defines the rating
codes. Second, those factors receiving "A" or "B" ratings are prioritized, since typically these factors
must be eliminated before a plant will achieve a consistent desired performance.
Adverse Effect of Factor on Plant Performance
Major effect on a long-term repetitive basis.
Minimum effect on a routine basis or major effect on a periodic basis.
Minor effect.
No Rating - factor has no adverse effect on plant performance (i.e.,
satisfactory assessment of this potentially performance-limiting item).
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POTW EXPERT - SUMMARY OFPOTENTfAL PERFORMANCE-LIMITING FACTORS
Plant Name; POTW^ % , " - ,,/- , ' ~ "c
CPJS Performed by: S, Seegel "
Bate: June 21,1990 ' r\
Plant Tfyper ,
This is a Suspended Growth POTW with a Conventional Activated Sludge
secondary treatment process.
Design Fldw: ^OOO^GQ gpd '
Actual Flow: 2,740,000 gpd
Plant Performance Summary* , \ , , ,
Tnis plant has reportedly met all of ifc BOD5 Permit requirements during the
past year. - , , _ ;,^], ff;f " !'__ -r?/' ''' ' »"" , .
This plant has teportedly met all of its TSS Permit fequirenients during the
past year. ' - - ;^""-" "-"
FACTORS^ f ^ ^ . -/ ',, ;,;: ,,.
POTW Expert has identified the following list of performance-limiting
factors, 3kx preparation for the exit meeting, it is up to the evaluator
to review this list and select those^factors that best represent the factors
limiting performance, ] " 11^ , -'
t Multiple factors'may be triggered by a single observation andjin some
f" cases may require feclassiflcatlon and/or deletion feom the list Review
the factors and their supporting observations to select the most applicable
factors from this potential 1M; After review and modification^ the
evaluator's final list mU be Displayed. vv
Ratings Factors / ,, ".,,-
; A OPERATION -* APPLICATtONS OF CONCEPTS'AND TESTING TO, PROCESS
;, CONTROL ,^ ^-,,, '^' \, ,--"<-' '" ',
A ADMINISTEATION «ILANT AtSMlNlSTRATORS - POLICIES
? A DESIGN-UNIT ADEQUACY-'SECONDARY >XERATOR"
B DESIGN* UNIT DESIGN'ADBQ'UACY-PRIMARY
B DESIGN-UNIT AD'E^UACY-SECONDARY-CLARMER
C ADMINISTRATION''- PLANT STAFF * MANPOWER V NUMBER
, C GFERATTON-TESTING -PERFORMANCEMONITORING
,: C OPERATIONAL-TESTING-PROCESS CONTROL TESTING
Figure 5-1. POTW Expert Performance-Limiting Factors Summary Report.
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5.3.3 Summary of Potential Performance-Limiting Factors Report
The Summary of Potential Performance-Limiting Factors Report is automatically displayed (see
Figure 5-1) and provides a 1-page summary describing the plant and ranking the potential factors that
may be limiting a plant's performance.
The summary PLF report represents POTW Expert's "soft recommendations" as to the classification
(e.g., A, B, C, NR) for each identified performance-limiting factor. The evaluator should carefully
review the list and associated classification and consider modifying the factors to reflect knowledge
outside the scope of POTW Expert's knowledge base. It should be noted that POTW Expert
simplifies the steps of a CPE by structuring the analysis and providing valuable insight. However,
POTW Expert's recommendations cannot be substituted for the judgment of the CPE evaluator in
assessing a particular facility.
The potential PLF summary report allows the user to review the system-assigned PLF ratings based
on the rating system described above. The user has the option of modifying the classifications using
the standard POTW Expert data entry format described in Chapter 2.
5.3.4 Final Performance-Limiting Factor Report
This report establishes the magnitude of the performance problem by listing the identified factors
with their associated explanations according to their adverse impact on plant performance.
Factors that are assigned an "A" are the major problems causing a performance deficiency. They
should be the central focus of any subsequent program to improve plant performance. Factors that
were identified as "A", "B", or "C" by POTW Expert but were changed to "NR" by the evaluator will
appear in the report for recordkeeping purposes.
5.3.5 Data Entry Detail Report
The Data Entry Detail Report provides a summary of all the data that has been entered into POTW
Expert. This report provides an easy way to review plant loading and performance data without
sequentially going through every data entry form. The user can display this report by pressing the
F6 function key while either a data entry form or report is displayed. It is recommended that the
evaluator save this report to document the evaluation.
5.4 SAVING AND PRINTING REPORTS
As described in the preceding sections, POTW Expert generates several reports during the system
consultation. POTW Expert provides the capability to either print it or save a report to a file. This
section describes the procedures for printing and saving POTW Expert's reports.
The command line at the bottom of a report display contains the Output function key, F3. Pressing
the function key, F3 causes a popup menu to appear, and the user may select either Save Report to
File or Print Report.
Save Report to File - This option saves the current report to a file in the POTWEX directory
or to a file on a selected remote disk (filename.SVR). Files are saved as an ASCII DOS text
file. POTW Expert will display a Data File popup menu where the user must specify one of
the following Save options:
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Print Report - This option allows the user to obtain a printed copy (hard copy) of the current
report Before selecting Print Report from the F3: Output menu, make sure your printer is
on and ready.
Save to an existing file
Save to another disk
-New -
- None -
To overwrite a current report file, highlight the file
name and press the ENTER.
To save a file to a remote disk, highlight the
appropriate disk (e.g., a:, b: or d:). Another popup
menu will appear which allows the user to overwrite a
current report file, create a new file, or cancel the
Save request. Path names are not allowed when
saving a file to a disk.
To create a new report file, select the new option and
enter a file name containing up to eight characters.
Path names are not allowed when saving a file to a
disk.
Cancel the save request.
Save All Reports to File - This option will only appear when the final report, Performance-
Limiting Factors Report, is displayed. It is recommended that the user selects this option to
maintain a complete record of reported information from the consultation. An additional
report, the Final Summary Performance-Limiting Factor Report, which is not displayed during
the consultation will appear as a part of this complete report.
5.5 FILES
POTW Expert has the ability to save two types of files, data files and report files. Because you may
be storing different file types with the same name on the same disk, POTW Expert distinguishes
between these files by adding a file extension to a file name as it is created.
Data files get the filename extension .SVR
Report files get the filename extension of either .RPT or .DB
You need not remember these extensions while using POTW Expert.
5.5.1 Data Files
Data files contain the information that the user inputs during a POTW Expert system consultation.
These files can be saved (using the F3 function key), and POTW Expert will label the file as
filename.SVR, where the user specifies the filename. The Save command should be used often
during a system consultation in case of accidents, such as power failure or an incorrect command.
Additionally, the consultation data should be saved at the end of a consultation.
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5.5.2 Report Files
POTW Expert accommodates two types of report files, CPE-related reports and a Data Entry Detail
Report. When the CPE reports which include the Major Unit Process Report, the Observation
Report, the Summary of Potential Performance-Limiting Factors Report, and the Performance-
Limiting Factors, are saved. POTW Expert labels these reports as filename.RPT, where the filename
is specified by the user. The Data Entry Detail Report, which is accessed and saved using the F6,
F3 function key combination, is labeled as filename.DB.
POTW Expert's results may form the foundation for the final CPE Report that is presented to the
plant staff and administrators at the exit meeting. The system is designed to facilitate the writing of
the final CPE Report by allowing report files to be imported to a word processor and edited.
Proper interpretation of the evaluation is necessary to provide the basis for recommending which
alternatives to pursue for the performance improvement phase. It is at this assessment phase, using
POTW Expert that the maximum application of the evaluator's judgement and experience is required.
All of POTW Expert report files are saved as ASCH DOS text files. These files contain text, spaces
tabs, and carnage returns. To make the file acceptable to other word processing programs
Formatting codes are not included. For more information on importing ASCII files into your word
processor, refer to the word processor's user documentation.
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APPENDIX A
Glossary of POTW Expert and Computer Terms
ASCII. American Standard Code for Information Interchange. A standardized 8-bit code used by
most computers for information exchange among data processing systems, data communications
systems, and associated equipment.
Arrow Keys. Directional keys (left, right, up, and down), usually located in the lower right of the
keyboard, that are used to move the cursor. In the POTW Expert Data Entry Forms and Response
Menus, pressing an arrow key highlights the next option of cell in the direction of the arrow pressed.
Autoexec.bat File. This batch file is automatically executed by DOS when the computer is turned on.
The file includes functions that can load memory resident programs and perform file management.
Backup. Files duplicated from a fixed disk drive or diskette to another diskette, which ensure
availability of the file in the event of loss or damage to the original.
Bounds Window. This window, displayed within the data entry screens, lists the accepted numeric
bounds or the defined multiple choice options. The bounds serve to verify user input to avoid
unacceptable data.
Bytes. A sequence or group of 8 bits that represents one character in a computer's memory or on
a disk.
CD\ (Change Directory). Typed at the DOS prompt, this command, followed by a subdirectory name,
moves to the named subdirectory. For example, typing CD\POTWEX selects (changes to) the
POTWEX subdirectory.
Central Processing Unit (CPU). The data processing and storage component of the computer's
hardware.
Chkdsk. This MS-DOS command checks the status of a disk drive and available computer memory,
and prints the results to the screen. Typing Chkdsk at the DOS prompt will run a disk check.
Command Line. Displays the POTW Expert-defined function keys at the bottom of each Data Entry
Form.
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Copy. This MS-DOS command copies files from one disk drive to another disk drive or diskette.
For example, typing copy (source) (destination), or copy A:data.all C:POTWEX, will copy the file
data.all from the A: drive to the POTWEX subdirectory on the C: drive.
Data. Information stored or processed by a computer. Data refers to graphic or textural
representations of facts, concepts, numbers, letters, symbols, or instructions used for communication
or processing.
Data Entry Form. The POTW Expert screen format to which most user information is entered. The
screen displays system variables that must be filled, response cellsAines, response bounds or options,
an expanded version of the current question, and the active function keys.
Directory. An area of a disk that stores the titles given to the files saved on a disk. The directory
contains data that identify the file name, size, attributes, date and time of creation, and a pointer to
locate the file.
Disk Operating System (DOS). A collection of programs that contains routines that allow the system
and the user to manage the computer's information and hardware. DOS must be loaded on the
computer before one can start other programs. DOS diskettes and documentation are usually
distributed with a new computer. When DOS has been installed on a computer, a "C:" usually
appears on the screen, and is referred to as the "DOS prompt."
Diskcopy. This MS-DOS command copies files from one diskette to a second diskette. When typed
at the drive label (A: or B:) of the floppy disk drive containing the source diskette, diskcopy instructs
the user to place the source and then the target diskette in the disk drive until all the information
has been copied to the target diskette. Any existing information on the target diskette will be
overwritten by information copied from the source diskette.
Diskette (Floppy Diskette). A circular piece of flexible material coated with a magnetic substance
used for storing information. Floppy disks can be inserted and removed from the computer's disk
drive to transfer information between computers. When inserted in the disk drive, the diskette spins
inside its square protective jacket while the computer writes and reads information to and from it.
Since there are openings hi the jacket to allow the read/write head of the disk drive to access the
data, the jackets are generally stored in protective sleeves or covers. The following terms refer to
the most common types of diskettes:
Double-density fdouble sidedX A double-density diskette has storage capacity for
360Kb (5 1/4 inch diskettes) or 720Kb (3 1/2 inch diskettes).
High-density. Allows up to 1.2Mb (5 1/4 inch diskettes) or 1.44Mb (3 1/2 inch
diskettes) of data storage.
POTW Expert is stored on one double-sided, high-density diskette that is included with this volume.
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ENTER. Also known as Return, this key, located to the right of the character keys on the keyboard,
selects data and executes system commands.
Expanded Question Window. Located near the bottom of the POTW Expert Data Entry Screens,
this window displays an expanded version of the current question.
Extended Memory. RAM memory above the conventional 640 kilobytes available in a 286/386-based
computer. Additional memory allows the system to execute commands and process files more quickly.
Extension. A one-to-three-character identifier that follows a filename. The extension further defines
or clarifies the filename, often by specifying the type of file. The extension is separated from the
filename by a period (.).
File. A group of related data or programs, called records, or entries, that are stored together on disk.
Text files consist of words and sentences. Program files consist of code and are used by computers
to interpret and execute commands.
Floppy Disk Drive. A mechanical device that accesses and stores information on a diskette. Most
computers have either one or two floppy disk drives, labelled A: and B:. If there is one drive, it is
usually called labelled the A: drive. If there are two drives, the A: drive is usually the one on top or
on the left. r
Formatting. Preparing a disk so that the computer can read or write to it. Formatting checks the
disk for defects and constructs an organizational system to manage data on the disk.
Free Memory. Available RAM memory.
Function Keys. Special-purpose keys that can be programmed to perform various operations. These
keys can serve many different functions depending on the software being used. POTW Expert uses
function keys for a number of operations. These "active" keys, whose definitions are displayed in the
command line on most system screens, are defined in Chapter 2.
Hard Disk Drive. The hard disk, commonly called the "C: drive," is part of the computer's hardware,
and contains magnetic media used to permanently store information. Because the information is
stored magnetically, it can be retrieved, recorded over, or erased. If no specific action is taken to
alter or erase the information, it will remain available for use. A light will blink when data are being
read from or written to the hard drive.
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Hardware. The physical components that make up a microcomputer (i.e., monitor, printer, disk
drives, etc.).
Help. POTW Expert'defines the function key Fl as the Help function. Pressing Fl displays the help
text when clarification or further background information is necessary for the current POTW Expert
question.
Inverse Video. A form of highlighting a character, field, or cursor by reversing the color of the
character, field, or cursor with its background.
Kilobytes (Kb). A unit of information storage (in a computer's memory or on a disk). One kilobyte
equals 1,024 bytes.
Mapmem. This function runs a check of available computer memory and prints the results to the
screen. Typing mapmem at the POTWEX prompt will execute a memory check using the file that
comes with the POTW Expert software.
Megabyte (Mb). A unit of information storage (in a computer's memory or on a disk). One
megabyte equals 1,048,576 bytes.
Monitor. The monitor is the piece of hardware that contains the computers display screen. POTW
Expert will run on a monochrome or a color monitor.
Question List Window. This window within the POTW Expert Data Entry Form lists the system
variables that the user must define during a consultation. The variables are presented in question
form.
RAM (Random Access Memory). The part of the memory that the computer can both read and
write to. Also called the working memory, random access memory (RAM) is where the computer
stores the programs and data that it is currently processing. Working memory is commonly measured
in kilobytes of RAM. RAM refers to a storage area that is temporary and can be reused and
rewritten multiple times. When started, the POTW Expert program is loaded into the computer's
working memory. When a sample data set is loaded into POTW Expert for editing or processing,
it is loaded into memory from the POTWEX directory on the hard disk. If a sample data set has
been saved within POTW Expert, it has been saved to the hard disk, and you may erase the current
working memory without losing your work.
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Response Menu. A list of response options that can be scrolled through using the arrow keys and
selected using ENTER. POTW Expert presents menus in situations where the user must select one
of a number of different response options. For example, in the third POTW Expert introductory
screen, Start New Session, Load Saved Data, and Continue are options listed in the Response Menu.
Some menus appear automatically, and some can be called to the screen by pressing F10: Menu or
the insert key.
Response Window. The POTW Expert window within the Data Entry Form screen that includes the
response cells (or lines) corresponding to each system question. User inputs are entered into this
window.
Single Answer Format. The POTW Expert input screen format requesting a number or multiple
choice selections for one question. The screen includes an expanded and abbreviated version of the
question, answer bounds or choices, and a response window.
Subdirectory. Subdirectories exist as files within a parent directory. Subdirectories are set up to
organize the files on a hard drive. If a hard disk is likened to a file cabinet, directories are the file
cabinet's drawers. The POTW Expert installation process automatically sets up a subdirectory called
POTWEX. All POTW Expert program files are stored in the POTWEX subdirectory, and they are
loaded into the working memory when POTW Expert is installed. Any file stored on the hard disk
may be written to a floppy disk for transferral to another machine.
Window. An on-screen box within which text is displayed. Windows serve to organize the screen by
grouping similar information together. Windows appear automatically or are called to the screen by
a function key.
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APPENDIX B
Definitions for Assessing Performance-Limiting Factors
Category Explanation
A. Administration
1. Plant Administrators
a. Policies
b. Familiarity with Plant
Needs
c. Supervision
d. Planning
2. Plant Staff
a. Manpower
1) Number
2) Plant Coverage
3) Workload Distribution
Do staff members have authority to make required operation
(e.g., adjust valve), maintenance (e.g., hire electrician), and/or
administrative (e.g., purchase critical piece of equipment)
decisions, or do policies^ require a strict adherence to a "chain
of command" (which has caused critical decisions to be
delayed and in turn has affected plant performance and
reliability)? Does any established administrative policy limit
plant performance (e.g., non-support of training; industrial
contributions not being controlled; or plant funding too low
because of campaign to avoid rate increases)?
Do administrators have a first-hand knowledge of plant needs
through plant visits or discussions with operators? If not, has
this been a cause of poor plant performance and reliability
through poor budget decisions, poor staff morale, poor
operation and maintenance procedures, poor design decisions,
etc.?
Do the management styles, organizational capabilities,
motivational skills, budgeting skills, or communication
practices at any management level adversely impact the plant
to the extent that performance is affected?
Does lack of long-range plans for facility replacement,
emergency response, etc., adversely impact plant performance?
Does a limited number of people employed have, a detrimental
effect on plant operations or maintenance (e.g., not getting
the necessary work done)?
Is plant coverage adequate to accomplish necessary
operational activities? Can appropriate adjustments be made
during the evenings, weekends, or holidays?
Does the improper distribution of adequate manpower (i.e., a
higher priority on maintenance tasks) prevent process
adjustments from being made or cause them to be made at
inappropriate times, resulting in poor plant performance?
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4) Personnel Turnover
b. Morale
1) Motivation
2) Pay
3) Work Environment
c. Staff Qualifications
1) Aptitude
2) Level of Education
3) Certification
d. Productivity
3. Financial
a. Funding
b. Expenditures
c. Bond Indebtedness
Does a high personnel turnover rate cause operation and/or
maintenance problems that affect process performance or
reliability?
Does the plant staff want to do a good job because they are
motivated by self-satisfaction?
Does a low pay scale or benefits package discourage more
highly qualified persons from applying for operator positions
or cause operators to leave after they are trained?
Does a poor work environment create a condition for more
"sloppy work habits" and lower operator morale?
Does a lack of capacity for learning or understanding new
ideas by critical staff members cause improper operations and
management (O&M) decisions leading to poor plant
performance or reliability?
Does a low level of education result in poor O&M decisions?
Does a high level of education cause needed training to be
felt unnecessary?
Does a lack of adequately certified personnel result in poor
O&M decisions?
Does the plant staff conduct the daily operation and
maintenance tasks in an efficient manner? Is time used
efficiently?
Does a lack of available funds (e.g., inadequate rate structure)
cause poor salary schedules, insufficient spare parts that result
in delays in equipment repair, insufficient money for capital
outlays for improvements or replacement, etc.?
Does the manner in which available funds are used cause
problems in obtaining needed equipment, staff, etc.? Are
funds spent on lower priority items while needed, high-priority
items are unfunded?
Does the annual bond debt payment limit the amount of funds
available for other needed items such as equipment, staff,
etc.?
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B. Maintenance
1. Preventive
a. Effective/Formal Program
b. Spare Parts Inventory
2. Corrective , -...-.
a. Procedures
b. Critical Parts Procurement
c. Technical Guidance
(Maintenance)
3. General
a. Housekeeping
b. References Available
c. Staff Expertise
d. Technical Guidance
(Maintenance)
Does the absence or lack of an effective scheduling and
recording procedure cause unnecessary equipment failures or
excessive downtime that results in plant performance or
reliability problems?
Does a critically low or nonexistent spare parts inventory
cause unnecessary long delays in equipment repairs that result
in degraded process performance?
Are procedures available to initiate maintenance activities on
observed equipment operating irregularities (e.g., work order
system)? Does a lack of emergency response procedures
result in failure to protect process needs during breakdowns
of critical equipment (e.g., maintaining oxygen supply to
organisms during blower breakdowns)?
Do delays in getting replacement parts caused by procurement
procedures result in extended periods of equipment
downtime?
Is technical guidance for repairing or installing equipment
necessary to decrease equipment downtime; is it available and
retained?
Does a lack of good housekeeping procedures (e.g., grit
channel cleaning; bar screen cleaning; unkempt, untidy, or
cluttered working environment) cause an excessive equipment
failure rate?
Does an absence or lack of good equipment reference sources
result in unnecessary equipment failure and/or downtime for
repairs (e.g., includes maintenance portion of O&M manual,
equipment catalogs, pump curves, etc.)?
Does the plant staff have the necessary expertise to keep the
equipment operating and to make equipment repairs when
necessary?
Does inappropriate guidance for repairing, maintaining or
installing equipment from a technical resource (e.g., equipment
supplier or contract service) result in equipment downtime that
adversely affects performance?
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e. Equipment Age
Does the age or outdatedness of critical pieces of equipment
cause excessive equipment downtime and/or inefficient process
performance and reliability (due to unavailability of replacement
parts)?
C. Design
1. Plant Loading
a. Organic
b. Hydraulic
c. Industrial
d. Toxic
e. Seasonal Variation
f. Infiltration/Inflow
g. Return Process Streams
2. Unit Design Adequacy
a. Preliminary
b. Primary
c. Secondary
1) Process Flexibility
Does the presence of "shock" loading characteristics over and
above what the plant was designed for, or over and above what
is thought to be tolerable, cause degraded process performance
by one or more of the loadings (a-e) listed below?
(e.g., high-volume on-off station pumps)
(e.g., winter flows at ski resort)
Does excessive infiltration or inflow cause degraded process
performance because the plant cannot handle the extra flow?
Does excessive volume and/or highly organic or toxic return
process flow stream cause adverse effects on process
performance, equipment problems, etc.?
Do the design features of any preliminary treatment unit cause
problems in downstream equipment or processes that have led
to degraded plant performance?
Does the performance of the primary treatment unit contribute
to problems in downstream equipment or processes that have
degraded plant performance? Do the units have any design
problem areas that have caused less than required performance
to meet overall treatment objectives?
Does an unavailability of adequate valves, piping, etc. limit
plant performance and reliability when other modes of
operation of the existing plant can be utilized to improve
performance (e.g., operate activated sludge plant in plug, step,
or contact stabilization mode; operate RBCs in step loading
mode)?
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2) Process Controllability
3) "Aerator"
4) Clarifier
d. Advanced Waste Treatment
e. Disinfection
f. Sludge Wasting
Capability*
g. Sludge
Thickening/Dewatering*
h. Sludge Treatment*
i. Ultimate Sludge Disposal*
Do the existing process control features provide adequate
adjustment and measurement over the appropriate flows (e.g.,
return sludge) in the range necessary to optimize process
performance; or is the flow difficult to adjust, variable once
adjusted, not measured and recorded, not easily measurable,
etc.?
Does the type, size, shape, or location of the "aerator" (aeration
basin, trickling filter, RBC, etc.) hinder its ability to adequately
treat the sewage and provide for stable operation? Is oxygen
transfer capacity inadequate?
Does a deficient design cause poor sedimentation due to the
size, type, or depth of the clarifier; placement or length of the
weirs; or does inadequate scum removal adversely affect
performance?
Advanced waste treatment is any process of wastewater
treatment that upgrades water quality to meet specific effluent
limits that cannot be met by conventional primary and
secondary treatment processes (i.e., nitrification towers,
chemical treatment, multimedia filters). (Space is available in
the Checklist to accommodate advanced processes encountered
during the CPE.)
Does the unit have any design limitations that contribute to its
inability to accomplish disinfection (i.e., proper mixing,
detention time, feed rates, feeding rates proportional to flow,
etc.)?
Does an inability to waste sludge adversely affect plant
performance? Can desired volume of sludge be wasted? Can
sludge wasting be adequately controlled? Can sludge wasted
be sampled without extreme difficulty?
Does the type or size of the sludge thickening/dewatering
process hinder sludge wasting capability or sludge treatment
such that plant performance is adversely affected?
Does the type or size of the sludge treatment process hinder
sludge stabilization (once sludge Las been removed from the
wastewater treatment system), thereby causing process
operation problems (e.g., odors, limited sludge wasting, poor
quality recycle streams, etc.)?
Is the ultimate sludge disposal program, including facilities and
disposal area, of sufficient size and type to adequately handle
the sludge production from the plant? Are there any specific
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areas that limit ultimate sludge disposal such as seasonal
weather variations or crop harvesting?
* For the purposes of this manual, these factors are assessed on their impact on a plant to achieve
final effluent requirements and are not assessed relative to meeting sludge regulation criteria.
3. Miscellaneous
a. Plant Location
b. Unit Process Layout
c. Lack of Unit Bypass
d. Flow Proportioning Units
e. Alarm Systems
f. Alternate Power Source
g. Process Automation
The design "miscellaneous" category covers areas of design
inadequacy not specified in the previous design categories.
(Space is available in the Checklist to accommodate additional
items not listed.)
Does a poor plant location or poor roads leading into the plant
cause it to be inaccessible during certain periods of the year
(e.g., winter) for chemical or equipment delivery or for routine
operation?
Does the arrangement of the unit processes cause inefficient
utilization of operator's time for checking various processes,
collecting samples, making adjustments, etc.?
Does a lack of a unit bypass cause plant upset and long-term
poor treatment when a short-term bypass could have minimized
pollutional load to the receiving waters; cause necessary
preventive or emergency maintenance items to be canceled or
delayed; or cause more than one unit to be out of service when
maintaining only one unit?
Does inadequate flow proportioning or flow splitting to
duplicate units cause problems or partial unit overloads that
degrade effluent quality or hinder achievement of optimum
performance?
Does the absence or inadequacy of an alarm system for critical
pieces of equipment or processes cause degraded process
performance?
Does the absence of an alternate power source cause problems
in reliability of plant operation leading to degraded plant
performance?
Does the breakdown or improper workings of automatic process
monitoring or control features cause degradation of process
performance? Could the availability of automatic monitoring
or control devices enhance process control and improve plant
performance?
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h. Lack of Standby Units
for Key Equipment
i. Laboratory Space and
Equipment
j. Process Accessibility for
Sampling
k. Equipment Accessibility for
Maintenance
1. Plant Inoperability Due to
Weather
m. Equipment Malfunction
D. Operation
1. Testing
a. Performance Monitoring
b. Process Control Testing
2. Process Control Adjustments
a. Wastewater Treatment
Does a lack of standby units for key equipment cause
degraded process performance during breakdown or during
necessary preventive maintenance activities?
Does the absence of an adequately equipped analytical and/of
process control laboratory limit plant performance?
Does the inaccessibility of various process flow streams (e.g.,
recycle streams) for sampling prevent needed information from
being obtained?
Does the inaccessibility of various pieces of equipment cause
extensive downtime or difficulty in making needed repairs or
adjustments?
Are certain units in the plant extremely vulnerable to weather
changes (e.g., cold temperatures) and, as such, do not operate
at all or do not operate as efficiently as necessary to achieve
required performance?
Does malfunctioning equipment (i.e., not functioning in
accordance with design) cause deteriorated process
performance?
Are the monitoring tests truly representative of plant
performance (e.g., does a sludge accountability analysis support
plant performance records)?
Does the absence or wrong type of process control testing
cause improper operational control decisions to be made?
b.
Is the operators lack of a basic understanding of wastewater
treatment (e.g., limited exposure to terminology, lack of
understanding of the function of unit processes, etc.) a factor
in poor operational decisions and poor plant performance or
reliability?
Application of Concepts and Is the staff deficient in the application of their knowledge of
Testing to Process Control wastewater treatment and interpretation of process control
testing such that improper process control adjustments are
made?
c.
Technical Guidance
(Operations)
Does inappropriate operational information received from a
technical resource (e.g., design engineer, equipment
representative, State trainer
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d. Training
e. Plant Familiarity
4. O&M Manual/Procedures
a. Adequacy
b. Use
E. Miscellaneous
Does inattendance at available training programs result in poor
process control decisions by the plant staff or administrators?
Does the short time on the job and associated unf amiliarity with
plant needs result in the absence of process control adjustments
or in improper process control adjustments being made (e.g.,
opening or closing a wrong valve, turning on or off a wrong
pump, etc.)?
Does inappropriate guidance provided by the O&M
Manual/Procedures result in poor or improper operational
decisions?
Does a good O&M Manual/Procedures, not used by the
operator, cause poor process control and poor treatment that
could have been avoided?
The "miscellaneous" category allows addition of factors not
covered by the above definitions. Space is available in the
Checklist to accommodate these additional items.
*US,COVWNMENTP|UNT1NG OFFICE 199 3 -750 4o2 Ao29'»
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