United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600 2-80-089
Ml ay 1980
Research and Development
Evaluation of
Full-Scale Sugar
Beet Transport
Water Solids
Dewatering System
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-80-089
May 1980
EVALUATION OF FULL-SCALE SUGAR BEET
TRANSPORT WATER SOLIDS DEWATERING SYSTEM
by
M. F. Figueroa, F. A. Brunner,
F. S. Williams, and J. C. Buzzell, Jr.
Sverdrup & Parcel and Associates, Inc.
St. Louis, Missouri 63101
Contract No. 68-01-3289
Project Officers
-»
Kenneth A. Dostal
Harold W. Thompson
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory-Cincinnati (lERL-Ci), U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory-
Cincinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
The report evaluates a full-scale sludge dewatering system at an oper-
ating beet sugar plant. The system was intended to enhance disposal options
and decrease odor potential by reducing the water content of waste solids.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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ABSTRACT
The objectives of this study were to evaluate a full-scale vacuum
filtration system for dewatering solids removed from the transport water in
an operating beet sugar plant in terms of operational reliability and effi-
ciency, economics, and ultimate disposal of the dewatered solids. A post-
campaign study was also carried out to measure and characterize the odors
associated with beet sugar waste storage lagoons. The study provided an
opportunity to verify the findings of a 1972 study carried out under EPA
sponsorship (Grant 12060 ESC).
The site of this study was the MINN-DAK Farmers Cooperative in Wahpeton,
North Dakota. At this plant, the solids in the beet transport water are
removed in a clarifier and piped to the Mud House. Waste lime mud from the
sugar processing is added to the clarifier underflow to serve as a filter
aid. The combined sludge is dewatered on two vacuum filters. The filter
cake is pumped to a storage lagoon adjacent to the Mud House. The solids
handling system is operated 24 hours per day, seven days a week during the
campaign.
The findings of the study indicate that the solids handling system was
not functioning as intended. The vacuum filters received primarily waste
lime mud; the clarifier underflow largely bypassed the Mud House and went
directly to a storage lagoon. The major cause of this malfunction was that
the clarifier did not provide sufficient thickening. Other causes include
several minor design deficiencies and deviations from the criteria developed
in the earlier study. Operations in the Mud House were adjusted to compen-
sate for the various difficulties, resulting in bypass of most of the
clarifier underflow.
Because the solids handling system was not functioning as intended, the
economic evaluation was not carried out. Instead, the various components of
the total system were evaluated and modifications are presented that can be
implemented to improve the system so that the original goals for the system
can be achieved.
This report was submitted in fulfillment of Task Order 10 of Contract
No. 68-01-3289 by Sverdrup & Parcel and Associates, Inc., St. Louis, Missouri
under the sponsorship of the U.S. Environmental Protection Agency. This
report covers a period from September, 1976 to July, 1977, and work was
completed as of December, 1978.
iv
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
List of Abbreviations and Symbols ix
Acknowledgments x
1. Introduction 1
2. Conclusions 3
3. Recommendations 4
4. Background and Study Goals 5
5. System Description 9
Transport Water System 9
Activities Prior to Study 15
6. Study Procedures 18
Analytical Program 18
Flow Monitoring 20
Odor Study 21
7. Results 28
System Operation 28
Vacuum Filtration 31
Odor Evaluation 47
Ultimate Disposal of Solids 58
8. Discussion 59
Data Collection 59
Results - Dewatering System 60
Results - Odor Study 60
System Design and Performance 61
System Modifications 67
Ultimate Disposal of Solids 72
\
References 74
Bibliography 75
Appendices
A. Additional Data Tables 76
B. Mud House Log Summary 81
C. Monitoring and Analytical Programs 103
D. Mud House Operating Log Sampling Instructions 106
Glossary
109
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FIGURES
Number Page
1 Transport water system process schematic 10
2 Mud house layout: vacuum filtration system 12
3 Plan of mud house and storage lagoons 16
4 Floating gas collector 23
5 Gas production sampler 25
6 Typical process flows 43
7 Waste storage ponds - odor vs. time 50
8 Waste storage ponds - gas production vs. time 52
9 Odor, COD, and temperature vs. time - Pond No. 2 .... 53
10 Gas and TDS vs. time - Pond No. 2 54
11 Water and solids balance for beet transport and
clarifier systems 63
12 Proposed process flow schematic 68
13 Proposed plan of mud house and storage lagoons 69
VI
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TABLES
Number Page
1 Design Loadings for Vacuum Filtration Process 14
2 Sampling and Analytical Schedule 19
3 Temperature and pH Data 32
4 Total and Volatile Solids Data 34
5 Total and Dissolved COD Data 36
6 Total and Dissolved Calcium Data 38
7 Bulk Density and Percent Solids Data 40
8 General Data of a Typical Day's Operation 45
9 Filtration Process Data - Typical Day's Operation. . . 46
10 Filtration Process Data - Special Five-Day Period
Operation 48
11 Odor Concentration 49
12 Gas Production 51
13 Results of Chemical Analysis - May 26, 1977
Teflon Bag Sample 56
14 Results of Chemical'Analysis - July 12, 1977
Teflon Bag Sample 57
15 Process Additives and Eventual Disposal 62
16 Clarifier Design and Performance 64
17 Vacuum Filtration Process Design and Performance ... 66
A-l Filtrate Flow Rate Data 76
A-2 Clarifier Underflow to Vacuum Filters 77
VII
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TABLES (Continued)
Number Page
A-3 Instantaneous pH and Viscosity Data 78
A-4 Supplementary Data 79
A-5 MINN-DAK's 1976-1977 Campaign Wastewater Inventory . . 80
viii
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ABBREVIATIONS
BOD
COD
cu m/day
GC
gpd/sq ft
kg/sq m/day
mg/1
ou/cf
TDS
SYMBOLS
Ca
CaO
LIST OF ABBREVIATIONS AND SYMBOLS
biochemical oxygen demand
chemical oxygen demand
cubic meters per day
gas chromatography
gallons per day per square foot
kilograms per square meter per day
milligrams per liter
odor units per standard cubic foot
total dissolved solids
calcium
calcium oxide
IX
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ACKNOWLEDGMENTS
We gratefully acknowledge the assistance of Mr. Harold Thompson, Project
Officer, and his valuable guidance in preparing and reviewing this document.
We are also indebted to Mr. Gerald W. Shannon, Mr. Gerald A. Pietrzak,
and Mr. W. Douglass Ransdell, all of the MINN-DAK Farmers Cooperative, for
their cooperation, assistance, and patience.
Mr. Donald L. Stewart, of Stewart C&R, Inc., and Mr. Milos Tomaides, of
MMT Environmental, Inc. are recognized for their guidance and technical
assistance.
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SECTION 1
INTRODUCTION
The processing of sugar beets into refined sugar requires water-
supported systems to transport and clean the beets. The quality of this
water varies considerably and is affected by the range of conditions that
may occur during harvest and storage of the beets. Under normal conditions
of harvest and delivery to the processing facility, a once-through transport
water would typically have a BOD value in the 200 to 400 mg/1 concentration
range and a mud tare of 3 to 6 percent of the total weight of the beets.
However, when beets are stored into the late winter, the BOD of the transport
water can run as high as 25,000 mg/1, and when harvest conditions are adverse,
the mud tare can be as much as 20 percent.
Historically, beet sugar processing plants pumped water from a fresh
water source and used it for contact condensers on vacuum pans and evapora-
tors . The warm condenser waters were used for transport water and other
process requirements and the resulting wastewater was discharged directly to
the most readily available surface water. The wastewater volume consisted
of the fresh water, the water gained from beets during evaporating and
boiling operations, and the pulp press water.
The first major step by the industry toward reducing the BOD loading in
beet transport water was to remove pulp press water from the beet transport
system and return it to the diffuser. This substantially reduced the BOD of
the transport water but di'd nothing to lower the solids concentration gene-
rated by the mud tare. Settling ponds were used to settle out these solids
before the supernatant was discharged to a receiving surface water.
As wastewater discharge regulations became more restrictive, holding
ponds were introduced into the system to partially stabilize the organic
load prior to discharge during spring freshet periods. This innovation
generated many spin-off problems of which odor was the most troublesome from
the standpoint of technological control and public relations.
Offensive odors have been recognized for some time as a major problem
in the beet sugar industry. The odors can arise during and after the
processing of the beets. The majority of the odors emanate from the process
wastewater and waste sludge lagoons during the spring thaw and the summer
months. The high waste load in the lagoons has been, and is currently, the
subject of several treatability studies. While a number of these studies
have noted the odor problem, very little investigative effort has been
directed toward it.
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The closed loop system was introduced by the beet sugar industry as a
means of promoting better water management through lower fresh water usage.
This approach resulted in a water use reduction, but did little to alleviate
organic loadings or the odors resulting from the biodegradable constituents
of the transport water.
The present study was designed to evaluate a full-scale vacuum filtra-
tion system used to dewater sludge from a clarifier in a closed loop water
transport system. Of interest were the technical and economic feasibility
of this solids handling method and the potential benefits in terms of ulti-
mate disposal of the solids and reduction of associated odors. An ancillary
study was carried out to measure and characterize the odors emanating from
beet sugar waste storage lagoons.
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SECTION 2
CONCLUSIONS
The results of measurements and analyses carried out during the 1976-77
campaign show that the solids handling system was not functioning in the
manner supposed at the outset of the study. The underflow solids from the
transport water system were largely bypassed at the vacuum filter house (Mud
House) and diverted to a storage lagoon, in effect nullifying the purpose of
the vacuum filter operation. Instead, waste lime mud, which was to serve as
a filter aid, comprised the bulk of the feed to the filters most of the
time.
t
The major reason for the malfunction of the system was the incapacity
of the clarifier to adequately thicken the underflow prior to delivery to
the vacuum filters. This factor, plus a variety of minor design and control
deficiencies, made it virtually impossible to operate the existing system as
intended without frequent and severe operating problems and shutdowns.
Because the solids handling system was not functioning properly, the
technical and economic feasibility of this approach could not be determined
in a meaningful way. Instead, the system components were evaluated and
suggestions provided whereby the system could be modified so that the desired
results could be obtained.
The results of the odor study demonstrated that various sulfur-con-
taining compounds are responsible for much of the unpleasant odor. Measure-
ments of gas production rates, odor type and concentrations, temperature,
and wastewater COD, TDS, and pH provided some preliminary correlations, but
it was not possible to pinpoint conditions that could be controlled to
effect significant odor reduction.
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SECTION 3
RECOMMENDATIONS
Further study of vacuum filtration dewatering of transport water solids
is not feasible at the MINN-DAK plant until the solids handling system is
modified. An in-depth engineering analysis should be made of the various
components discussed in Section 8 so that, design criteria can be developed
for use in modifying the system.
Evaluation of the odor control benefits of the vacuum filtration
approach also is not feasible at the MINN-DAK plant until after the system
has been modified and used during one campaign.
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SECTION 4
BACKGROUND AND STUDY GOALS
Several research programs have been carried out to solve some of the
problems confronting the beet sugar industry but they have been directed
mostly at the problem of organic loadings of the wastewater. They have
succeeded in determining that the separation and handling of solids is only
the first step toward achieving a comprehensive transport water management
program.
The composition of the transport water is complex because the water
contains not only water-soluble materials but also solid organic material
such as beet tissue, leaves, stems, etc., plus the soil particles carried
into the system on the beets. The transport water may also contain materials
introduced from in-plant operations such as scrub waters from boiler house
and pulp drier stack clean-up and routine factory wastewaters. Thus, signi-
ficant amounts of sulfur, ammonia, foam-breaker compounds, etc. are present
to interact with the soil-borne bio-systems that are present in the system.
This complex mixture must be carefully monitored and regulated to
prevent acid fermentation with the resultant low pH that can damage equipment
and possibly release hydrogen sulfide in factory work areas. Control of
transport water pH is accomplished by the addition of lime or a biocide.
While this method may give adequate control, it inhibits the reduction of
biodegradable materials in the system and thus passes the loading on to
subsequent steps in the wastewater treatment system.
Gravity separation of transport water solids is usually included in
closed loop systems. Mechanical clarifiers permit the continuous removal of
the solids for subsequent processing and disposal. Clarifier underflow
contains a mixture of organic and inorganic solids and dissolved materials,
of variable pH and solids concentrations, and is inoculated with a variety
of microorganisms. Separation of the organic load carried by this solids
fraction significantly reduces the BOD and odor potential of the liquid
phase.
In addition to the benefits of BOD and odor reduction, a water manage-
ment program utilizing compact mechanical treatment systems can reduce the
land and energy requirements of a large-volume wastewater lagoon system and
alleviate the pressure of residential encroachment. These factors gave
impetus to EPA support of the beet sugar industry's efforts to conduct
studies aimed at developing criteria for the design and construction of
treatment facilities to separate the solid and liquid phases of the transport
water. An EPA grant (12060 ESC) to conduct a study of the separation,
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dewatering, and disposal of sugar beet transport water solids was awarded to
the American Crystal Sugar Company (ACS) in 1970. The study, conducted at
Crookston, Minnesota, dealt with clarification studies of a beet transport
water recycle system, a pilot plant feasibility study for dewatering of
transport solids by vacuum filtration, and land.disposal of the resulting
filter cake. (1)
Phase Two of this grant study was to have been an engineering evaluation
of a plant-scale dewatering facility. However, due to a number of circum-
stances, the grant was terminated in 1974 before the second phase began.
Some of the findings of the ACS study were later incorporated in the design
of the transport water treatment facilities of two recently constructed beet
processing plants in the Red River Valley: the American Crystal Sugar
Company plant at Hillsboro, and the MINN-DAK Farmers Cooperative plant at
Wahpeton, both plants being located in North Dakota.
To evaluate these systems, EPA contacted MINN-DAK late in the summer of
1976 and proposed to have a contractor carry out an evaluation of its trans-
port-water-solids dewatering system and the subsequent management of these
dewatered solids. MINN-DAK was receptive to EPA's proposal. As a result,
Sverdrup & Parcel, acting as the contractor for EPA, conducted the evaluation
during the 1976-77 campaign. Mr. Donald Stewart, of Stewart C & R, Inc.,
who actively participated in the ACS study, agreed to act as a beet-sugar-
processing environmental consultant for the project. The study was autho-
rized on October 13, 1976. The data collection for the campaign period took
place between November 14, 1976 and January 13, 1977. This was followed by
a post-campaign data collection period from April to July, 1977.
This study was aimed at determining the technological feasibility of
vacuum filtration as an effective method to dewater beet transport water
solids, including the economic and environmental aspects of the ultimate
disposal of the resulting cake. With this in mind, the objectives of the
study were as follows:
1. Evaluate a full-scale sugar beet transport-water-solids vacuum
filtration dewatering process for operational reliability and
efficiency.
2. Determine the economics of the dewatering process.
3. Evaluate the adequacy of the method of ultimate disposal of the
dewatered solids.
4. Determine the economics of the ultimate disposal method as affected
by current and proposed regulations.
The site of this study was the MINN-DAK Farmers Cooperative located'in
Wahpeton, North Dakota, in the Red River Valley, the nation's sugar beet
bowl (1). The cooperative was organized in 1972 and the factory was com-
pleted in 1974 as a turn-key project by the West German firm of BMA Machinery
and Equipment Company. The general contractor for the construction was
Krause Anderson of Minneapolis, Minnesota. Precampaign statistics for
6
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1975-76 show that the cooperative had 270 stockholders and that it processed
beets grown by over 300 growers in an eight-county, two-state area comprising
over 21,000 hectares (52,000 acres). The plant, which was valued in the
fall of 1975 at about $31,600,000, has a beet slicing capacity of 4,535
metric tons (5,000 tons) per day (2). The plant does not incorporate the
Steffen process.
Dry growing conditions in the summer and fall of 1976 produced a low
yield of 22.5 metric tons per hectare (10 tons per acre) and a short cam-
paign. The growing area's precipitation was approximately 25 cm (10 in)
below normal for the period between May and August, as reported by Gordon
Rudolph in the August, 1976 edition of the Reporter, MINN-DAK1s official
publication (3). The 1976-77 campaign, MINN-DAK1s third, was officially
started on September 27, 1976, and the last slicing day was January 21,
1977, for a total of 117 operating days. Final campaign operating figures
were as follows:
Beets sliced: 409,776 metric tons (^51,765 tons)
Sugar produced: 53,953 metric tons (59,484 tons)
Pellets produced: 25,001 metric tons (27,564 tons)
Molasses produced: 27,610 metric tons (30,441 tons)
Dirt tare on beets: 3.3% dry solids by weight
Although the cooperative had not developed a program to provide directly
for the ultimate disposal of solids, MINN-DAK's agreement with the growers
includes a provision whereby beet cultivation is done on a three-year crop
rotation basis, i.e., a beet-growing parcel cannot be re-used for cultivation
of beets until two years, have elapsed. This is done to maintain the nutri-
tional stability of the soil and to prevent the spread of disease. MINN-DAK
indicated that the growers are also required, under this agreement, to take
a portion of the clarifier underflow solids in proportion to the quantity of
beets delivered the previous season. The growers may, at their discretion,
dispose of this material by spreading it on the fields they cultivate,
stockpiling it, or taking it to a sanitary landfill. The beet growers are
reluctant to use the sludge on their land, however, for fear of damaging
their crops. Other disposal means are not always available, and MINN-DAK is
seeking satisfactory alternatives for ultimate disposal of solids.
A sampling and analytical program for the study was designed. Four
streams were selected for analysis to determine the effectiveness of the
dewatering process: the clarifier underflow containing the transport water
solids; the lime mud used as the filtering aid; the filtrate, or liquid
fraction, from the vacuum filters; and the filter cake, or solid fraction.
The analytical program was divided into two data collecting periods,
dictated by both operating and climatic conditions, as follows: a November
to January campaign period to evaluate the operation of the vacuum filtra-
tion station with respect to process effectiveness and equipment reliability;
and an April to July post-campaign period to evaluate the results of the
process with respect to odor and gas production that took place during the
warmer months of the year.
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This report presents the results of the study, including descriptions
of systems and operations, data collected from the sampling and analytical
programs during both the campaign and post-campaign periods, and discussion
and interpretation of the findings. Proposed modifications to the system
are also presented.
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SECTION 5
SYSTEM DESCRIPTION
This section describes MINN-DAK1s transport water system, the primary
treatment clarifier, and the vacuum filtration units that dewater the clari-
fier underflow. The sludge storage lagoons are also described. Pertinent
activities by MINN-DAK prior to the start of the study are also outlined.
TRANSPORT WATER SYSTEM
MINN-DAK Farmers Cooperative operates a beet transport water recycle
system that includes primary treatment (clarification) to remove coarse and
settleable solids and vacuum filtration for dewatering the solids removed in
clarification. Lagoons are provided for the storage of both the filtered
solids (filter cake) and the unfiltered (bypassed) clarifier underflow
solids. A schematic process flow diagram of this system is shown in Figure
1.
Beets are dumped into a wet hopper at the head of the beet flume.
Water, serving as the transport medium, pushes the beets into the beet
flume, and down to the next processing station. The flow of beets is con-
trolled by a beet flume control wheel, the speed of which determines the
quantity of beets to be processed. Leaves and weeds, still carried along
with, the beets in the flume, are separated from the beets in a trash catcher
and eventually hauled off the site by truck. Some beets are also removed by
the trash catcher and are hand-picked and returned to the flume.
Rocks and coarse sand are separated from the beets by a rock catcher
prior to the beets' discharge, via a lifting wheel, into the beet washer.
At the beet washing station, intensive agitation and simultaneous addition
of fresh water remove soil particles still adhering to the beets. After the
washing procedure, the beets are sprayed with fresh water on a roller spray
table and arrive at the picking table .where any remaining leaves, rocks, or
other foreign matter are removed manually. The washed beets are transported
through an ascending belt conveyor to the slicing station and on to the
extraction process.
The flume water containing the soil, tailings, and other solids is
pumped to vibrating screens where coarse solids are screened out. This
water then flows by gravity to a grit chamber where sand and other heavy
particles are removed. After the grit chamber, about one-third of the water
volume is pumped to the pulp drier heat exchanger to raise the temperature
of the transport water. The transport water then flows by gravity to a sump
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LIME ROCK SCREENINGS SAND
WATER FOR TRANSPORT ^ ~cnrrNINC *. GRIT
BEET »• WATER * oCnCCMING > CHAMBER
1_
1
WA
LI
0
^
MIX
TA
1
VAC
FILT
L
L
J
SUPERNATANT
1 I
1 ~ CLAHIHth
ME 1 j SAMPLING/METERING
FACTORY \
| \ UNDERFLOW
\
;L , — BY-PASS
0 V
ING Ny| 1 ' Kyl \ ^ UNDERFLOW ^_
NK lAJ lAJ ^ LAGOON ^
MUD FREE WATER
MIXED HOUSE
SLURRY
SAMPLING STATION (TYPICAL)
r 9*^
CAKE 1 FILTER
HIM 1 ^^ rALi" fcl
cnc CAKt ^1
EHS " LAGOON H
^=A PUMPING J
^=^ FILTRATE .^^
J *\
WASTE TREATMENT 1
BIOLOGICAL ^ !|l!?--ir -rf
TREATMENT STORAGE
1
|
»^ TO STORARF 1 ACTIONS FOB
RECYCLE OR ULTIMATE DISCHARGE
Figure 1. Transport water system process schematic.
10
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where it is pumped at a rate of 34,440 cu m/day (6,320 gpm) to the clarifier
to begin a new cycle.
Primary Treatment
Clarification takes place in a shallow, circular, reinforced concrete
basin equipped with a traveling bridge. The bridge rotates around the basin
by means of a motorized wheel traveling on top of the interior weir wall.
The bridge is equipped with a motorized screw auger to break up ice, spray
jets to break up foam, and sludge squeegees, supported by vertical pickets,
that push the sludge to a concentric collecting trough located at about the
one-third point from the center. Sludge is lifted out of the clarifier by
means of a variable-speed pump through an adjustable snout that traverses
the trough at actual pumping rates ranging from 760 to 1,250 cu m/day (140
to 230 gpm), depending on sludge consistency. The clarifier supernatant
overflows through inclined and submerged ports within the interior weir wall
into a peripheral weir trough, and from there it flows by gravity to the
beet transport flume.
The clarifier basin has an inside diameter of 44 meters (144.3 ft), a
sidewater depth of 1.25 meters (4.1 ft), and a bottom slope, from the inner
wall down to the sludge trough, of about 1:80. The above dimensions yield a
surface area of 1,520 sq m (16,360 sq ft) and a volume of 1,900 cu m (67,080
cu ft). Weir loading is 249 cu m/m (20,000 gpd/ft). The hydraulic detention
time, at an influent rate of 34,440 cu m/day (6,320 gpm), is 80 minutes.
The overflow rate of the basin, at the influent flow rate, is 22.66 cu
m/day/sq m (560 gpd/sq ft). At an assumed soil tare of 5 percent, and a
plant production capacity of 4,535 metric tons (5,000 tons) of beets per
day, the dry solids loading on this basin becomes 149 kg/sq m/day (30.6
Ib/sq ft/day).
Vacuum Filtration
Vacuum filtration takes place at the Mud House, schematically illus-
trated in Figure 2. The clarifier underflow is pumped through a 10.2 cm
(4-inch) pipeline to the Mud House where the flow is directed, by means of
gate valves, to either the mixing tank or to the underflow storage lagoon.
Lime mud from the factory, used as an aid to clarifier underflow filtration,
is pumped to the mixing tank or directly to the north lagoon. (See Fig. 2).
The lime mud is the residue of the juice purification process. The milk of
lime- and carbon dioxide-treated juice is heated and thickened and the
resulting mud concentrate, containing calcium carbonate and removed non-
sugars, is vacuum-filtered at the factory. The filter cake (lime) is then
slurried and pumped to the Mud House through a 15.2 cm (6-inch) diameter
elevated insulated pipeline at a temperature of between 40° and 55°C (104°
to 131°F).
The mixing tank is a cylindrical-bottomed, open-topped, double-com-
partment, welded-steel tank approximately 5 m long and 1.6m wide (16.5 ft.
by 5.3 ft) and about 3.0 m (10 ft) high. The tank is equipped with a motor-
ized, rotating helical coil to mix the tank contents. Both the clarifier
underflow and the lime mud influent pipes enter the tank through an end
11
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Lime Mud from factory
fc Ncrf.h La-'oon
Vacuum Pumps
,x r— Filtrate
\Y~n \ Receivers
H*
Mixing '
Tank
Filtrate to Liquid Ponds
Underflow from
Clarifier
^
•*
t ,
Vacuum Filter
"^
v- — Sludge
Vv Hoppers
m
-
(W Screw conveyor /W\ 1 O ' ' OAA
&
Vacuum Filter
>w
Sludge
Pumps
Underflow by-pass
to south lagoon-
NOTES:
Filter Cake
to North
' Lapoor:
Only key equipment and'piping are shown.
Some piping shown schematically rather than actual layout to enhance clarity.
Figure 2. Mud house layout; vacuum filtration system.
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compartment that comprises about one-fourth of the tank. The tank contents
flow by gravity to the vacuum filters through a 20.3 cm (8-inch) pipe located
at the bottom of the tank. The mixing tank is also equipped with a clear
plastic tube that serves as a visual level indicator for the operators and
with an overflow pipe that discharges into a sump below. This sump also
collects filter wash water and general clean-up flows within the Mud House.
Filtration is carried out on two DMA vacuum drum filters, each having a
filter area of 63.8 sq m (687 sq ft), a diameter of 3.6 m (11.7 ft), and a
length of 5.7 m (18.7 ft). Each filter consists of a cylindrical drum
rotating in a pan filled with the sludge slurry. The drum, made of perfo-
rated steel plate, is covered by a filter cloth (Filter's Company, Inc., No.
06859) secured to the drum by wire bands spaced about 9 cm (3.5 inches)
apart. As the drum rotates, a vacuum is applied between the drum deck and
the filter medium. This causes water to be extracted and sludge solids to
be retained on the cloth. The vacuum filters typically operate with a
vacuum of 127 to 254 mm (5 to 10 inches) of mercury, and at a rotational
speed of 0.4 revolutions per minute. The vacuum filter main drive is powered
by a 14.9 kw (20 hp) motor. Each filter is also equipped with a 7.5 kw (10
hp) motor agitator to keep solids in suspension and a 1.5 kw (2 hp) pump and
piping to remove sand and other heavy solids that settle in the pan to the
top of the drum as it rotates.
Vacuum is provided by two Nash 200-2, 93.2 kw (125 hp) motor, vacuum
pumps. The filtrate is drawn to two vertical receiver tanks connected in
series where the level is maintained to provide separation of the air and
liquid phases. A pneumatic level controller actuates the operator of a
butterfly valve to regulate the flow out of the receivers. The filtrate is
pumped out of the Mud House through a 15.2 cm (6-inch) pipeline and is
discharged into liquid waste storage ponds. The filtrate can also be
returned to the clarifier. Table 1 shows design lime mud and filter cake
data, adjusted to achieve a balance.
As the drum completes its rotation and nears the point of discharge,
the cake is lifted from the cloth with air supplied by two Cycle Blower
Compressor blowers, 7CDL 17 H, Gardner Denver Co., 55.5 cu m/min (1960 cfm),
1.27 kg/sq cm (18 psig), 360 rpm, 55.9 kw (75 hp) motor. Then, with the aid
of a blade, the cake is removed from the drum and dropped into a screw
conveyor. Water is added to the cake for better pumping. The screw conveyor
moves the sludge toward the hoppers feeding two positive displacement sludge
pumps. The hydraulically powered dual-chamber Schwing PSP 17 pumps have a
volumetric displacement per chamber of 0.017 cu m (0.62 cu ft) at maximum
stroke. At an average rate of 13,260 strokes per day, and assuming a 75
percent effective stroke, each pump is capable of delivering about 335 cu m
(90,000 gal) of sludge per day.
The hydraulic system iis powered by a 93.2 kw (125 hp) motor. The
sludge is pumped to the sludge storage lagoon through an above-ground pipe-
line made of standard length sections of 15.2 cm (6-inch) carbon steel pipe
coupled with Victaulic fittings. At the end of the pipeline, there is a
derrick-like boom that projects out over the lagoon to distribute the sludge.
13
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TABLE 1. DESIGN LOADINGS FOR VACUUM FILTRATION PROCESS
INPUT/OUTPUT
Clarifier underflow
Solids
Water
Lime mud
Solids
Water
TOTAL INPUT
Filter cake
Clarifier solids
Lime mud solids
Water
Filtrate *
TOTAL OUTPUT
Mass
kkg/day
2,840
230
2,610
690
330
360
3,530
1,120
230
330
560
2,410
3,520
Volume
cu m/day
2,760
150
2,610
490
130
360
3,250
840
150
130
560
2,410
3,250
Percent
Weight
100
8
92
100
48
52
—
100
20
30
50
100
--
Density
kkg/cu m
1.03
1.58
1.00
1.40
2.47
1.00
1.09
1.33
1.58
2.47
1.00
1.00
—
* Assumes no significant solids content
-------
The wash water from washing the filters and clean-up of the Mud House
collects in a floor drain that discharges into a sump from where it is
pumped to the liquid storage ponds. Filter wash water was formerly recycled
to the mixing tank. This practice was stopped, however, when it was discov-
ered that oily and soapy materials in the wash water caused blinding of the
filter media.
Lagoons
A plot of the layout of the sludge storage lagoons and the Mud House is
shown in Figure 3. The 4.5 ha (11 acres), L-shaped, south lagoon is where
the bypassed clarifier underflow is retained. The rectangular north lagoon,
also having a surface area of 4.5 ha (11 acres), is where the filtered
sludge cake is stored. A drainage ditch around three sides of the north
lagoon channels free water from both lagoons to a point near the Mud House.
The free water is pumped to one of the wastewater storage lagoons by means
of submersible pumps lowered into the dead end of the ditch near the Mud
House. The free water is mixed with the filtrate and other factory-generated
liquid wastes. All of these wastes are stored for the winter, treated
during the intercampaign period, and either discharged or stored for recy-
cling in the industrial water supply system. The sludge storage lagoons
were designed to be cleaned every two or three years.
ACTIVITIES PRIOR TO STUDY
During each intercampaign period, in preparation for the next processing
season, the plant personnel carry out the necessary maintenance and overhaul
of equipment to be prepared for the breakneck pace that allows for few
interruptions once the sugar processing campaign has started. Major modifi-
cations, alterations, and additions to existing facilities are usually made
between February and September. During this period, treatment of wastewater
accumulated during the campaign is also carried out.
During the intercampaign period of 1976, the two sludge storage lagoons
were cleaned of the material accumulated during the previous two campaigns,
and extensive repairs were made on the vacuum filters and the sludge pumps
at the Mud House. The Mud House equipment repairs were performed by
MINN-DAK1s operating and maintenance personnel. The job of removing the
sludge from the lagoons was awarded to a contractor. The contractor brought
in bulldozers, trucks, and other earth moving equipment to perform this
work.
Independently of this study, and on its own initiative, MINN-DAK entered
into an agreement with a neighboring farmer to have some of the filter cake
lagoon contents spread and mixed on his farmland for the purpose of deter-
mining the feasibility of this disposal method. To this end, filter cake
sludge was applied in layers 7.6 and 12.7 cm (3 and 5 in) thick to two 0.4
hectare (one-acre) parcels. The sludge was disked and mixed with the soil
and the entire field was planted with wheat. Another portion of the filter
cake sludge was used to build up the lagoon dikes and the balance was hauled
by the contractor to a nearby trailer park construction site for use as fill
material.
• 15
-------
Drainage ditch
~1
SLUDGE CAKE STORAGE LAGOON
(North Lagoon)
Cake discharge pipeline
Boom
CLARIFIER UNDERFLOW STORAGE LAGOON
(South Lagoon)
-Clarifier underflow
-Filtrate
V
Free
water
V
Free
water
Figure 3. Plan of sgud House and storage lagoons.
-------
The Mud House equipment repairs consisted mainly of replacing the
vacuum filter agitators and installing a 20.3-cm (8-in) pipeline with a
quick-action valve for periodic discharge of sand and gravel accumulating in
the bottom of the filter pans to the filter cake lagoon. The agitators were
replaced because the original drive arms were not strong enough and were
bent by the sand load in the underflow from the clarifier. The other major
repair of Mud House equipment included rebuilding of the filter cake pump
cylinders, part of the normal maintenance for these pumps.
' 17
-------
SECTION 6
STUDY PROCEDURES
This section presents the details of the sampling program and analytical
methods used to characterize the two input and two output streams at the
vacuum filters. The flow monitoring procedures for these streams are also
outlined. The third part of this section describes the methodology of the
post-campaign study to measure the intensity and production rate and deter-
mine the chemical composition of the odorous gases generated at the sludge
and liquid waste storage ponds.
ANALYTICAL PROGRAM
A Monday through Saturday sampling and monitoring program was instituted.
The parameters and streams sampled and analyzed are presented in Table 2.
The sampling stations are shown in Figure 1. An operating log was also kept
(Appendix B) to provide data for use in evaluating the reliability of the
process. Data were collected in two separate groups: 1) 22-hour composite
grab samples collected up through January 6, 1977; and 2) data from 8-hour
composite grab samples collected after that date. Thus, typical around-the-
clock operation of the Mud House, as exemplified by the first group of data,
can be compared with a closely controlled and monitored period of operation
that was aimed at optimizing filtration of the clarifier underflow, as
exemplified by the second group. This special monitoring period is described
in detail in Section 7.
For the 22-hour sampling, equal-volume aliquots were collected at every
odd-numbered hour and composited into daily samples. The first sample
aliquot was collected at 9:00 a.m. and the last one at 7:00 a.m. of the
following day. With the exception of the lime mud sample, which was col-
lected at the factory by laboratory personnel, all samples were collected at
the Mud House by the operating personnel. The Mud House operators were also
asked to record, concurrently with collection of the samples, sampling and
operating equipment information in the log. The sampling instructions are
provided in Appendix D.
Self-cleaning piston type Strahman sampling valves were purchased and
installed on the clarifier underflow and the filter cake pipelines. The
filtrate, because of its low solids content, did not require this type of
valve, and the valve in place was used to obtain the samples. The lime mud
pipeline at the factory already had a self-cleaning sampling valve.
Each of the filtrate and the clarifier underflow sampling stations was
furnished with a stainless steel dial thermometer, a waste bucket, a col-
18
-------
TABLE 2. SAMPLING AND ANALYTICAL SCHEDULE
SAMPLING POINT *
ANALYSIS
Clarifier
Underflow
Lime
Mud
Filter
Filtrate Cake
Cake
Storage
Area
COD Total
COD Soluble
Ca Total
Ca Soluble
Temperature
Total Solids
Volatile Solids
pH
Bulk Density
Odor Number
Viscosity
1
2
1
1
3
1
1
1
1
4
5
1
2
1
1
3
1
1
5
1
2
1
1
3
1
1
1
,#
1
2
1
1
1
2
1
4
5
KEY
1
2
3
4
5
Daily: 6 days/week
Weekly
Instantaneous on each grab sample, as appropriate
Post-campaign
Test to be conducted on equipment or time available basis;
however, at least 3 analyses per sampling point were conducted.
Odor number was measured on samples taken from the wastewater lagoons.
It was not possible to separate the filtrate from other plant wastes.
19
-------
lecting bucket, a wide-mouth sample container, and a ladle to stir and
measure the sample aliquots. The lime mud and the cake storage sampling
stations had built-in sample collecting buckets, and sample aliquots were
measured with a spoon and placed into wide-mouthed sample containers. The
temperature of the lime mud was measured at the laboratory near the collec-
tion point. The filter cake samples were obtained by reaching down from the
platform into the cake discharge area of the filter with a long-handled
ladle. The samples were then placed in wide-mouthed containers. All con-
tainers remained tightly capped between collections.
Every morning, at the beginning of jthe first shift, the equal-volume
composite samples and the daily log sheet were taken to the factory labora-
tory. MINN-DAK's personnel reviewed the log sheets and entered the lime mud
temperatures recorded by the laboratory technicians. The samples, including
the lime mud sample collected at the factory, were analyzed during the
second shift to avoid conflict with the factory's main laboratory work
carried out during the first shift. Consequently, sample analyses were
started nine to ten hours after the last aliquot was added to each composite
sample. Although pH was one of the parameters measured, the delay between
sample collection and analysis rendered composite sample pH values unreliable
due to bacterial action. Only instantaneously measured pH values of grab
samples (shown in Table A-3 of the Appendix) were used in the analysis of
results. The samples were not preserved.
A list of references for the analytical methods employed is provided in
Appendix C. For quality control purposes, one set of samples was analyzed
in duplicate each week during the sampling program. In addition, a standard
solution of potassium biphthalate was analyzed daily with each set of COD
samples. Determinations of bulk density were made in triplicate. Sets of
EPA Quality Control Reference Samples were analyzed by the technicians at
MINN-DAK and at the Sverdrup & Parcel Water Laboratory. The results of
these analyses are also in Appendix C.
FLOW MONITORING
A survey of the dewatering facilities, conducted during the preliminary
stages of the project, revealed that there were inadequate provisions for
flow measurement and that a number of devices had to be installed. By the
time the project was authorized, the campaign was already under way, and
flow meters had to be specified, purchased, and installed quickly. Both
magnetic and ultrasonic flow meters were investigated. Magnetic flow meters
have been successfully used to measure the flow of slurries, but ultrasonic
flow meters have only recently appeared on the market. Time and installation
requirements, however, dictated the use of the latter. They could be deliv-
ered in a much shorter time and no process interruptions were involved in
their installation.
Clampitron flow meters (Cbntrolotron Corp.) were ordered and liquid
samples of the clarifier underflow, filtrate, and lime mud were shipped to
the meter manufacturer for testing and calibration. The manufacturer's
tests showed that ultrasonic flow -meters could be used for the first two
waste streams, but not with the lime mud flow because of its high solids
20
-------
concentration. Since ultrasonic meters could not be used, the volume of
lime mud delivered daily to the Mud House was calculated using an empirical
equation developed by MINN-DAK personnel. The equation states that the mass
of CaO generated by carbonation per day (available from factory production
records) divided by the concentration of CaO in the lime mud yields the
volume of lime mud per day.
A series of measurements relating flow rate to the percent motor load
of the pump was made to determine the amount of underflow pumped out of the
clarifier. With the percent motor load of the pump set at different posi-
tions, all within the normal operating range, the rise in level was timed at
the mixing tank. A curve was then plotted and flow was calculated based on
the average pump motor load setting for that day. The clarifier operator
recorded the pump setting every hour.
Late in the study, it was demonstrated that within the normal range of
clarifier pump settings, it was unnecessary to close the west valve leading
to the mixing tank to prevent underflow from entering the tank. All that
was needed to direct flow, either to the mixing tank or bypass to the lagoon,
was to open or close the east valve. A series of measurements was then made
to relate the amount of clarifier underflow entering the mixing tank to the
setting of the east valve. With the clarifier pump set at a given percent
load, the east valve was slowly closed until underflow began to enter the
mixing tank, at which point the length of the valve stem outside the valve
body was measured. The valve was then closed in 6 mm (1/4 inch) increments,
the level-of-rise versus time readings were recorded, and the flow rate for
each adjustment was calculated. Table A-2 of the Appendix, relating degree
of valve opening and percent motor load to flow rate, was prepared for the
benefit of the operators. The problem remained of not knowing the percent
motor load of the clarifier pump at any given time.
Two methods were considered for measuring the amount of filter cake
produced at the Mud House. The first method involved calculating the volume
of the cake produced per unit of time by multiplying the speed and the width
of the drum by the measured thickness of the cake. The second method
involved calculating the amount of cake produced using the volumetric dis-
placement of the pumps that transport the cake to the north lagoon. Since
the sludge volume calculated by this method would include the water added to
the cake to improve its flow characteristics, .the volume was adjusted by
multiplying by the ratio of the moisture content of the "dry" filter cake to
that of storage lagoon samples.
Mechanical counters were installed to record the number of pump strokes.
They started to malfunction soon after installation. The warm humid Mud
House environment caused condensation on the inside of the counter windows.
This was resolved by removing the windows and covering the openings with
plastic bottles to protect them from direct splashing.
ODOR STUDY
The odor study was carried out during the post-campaign period and
consisted of field collection of gas samples from the filter cake storage
21
-------
lagoon (lime pond), the clarifier underflow storage lagoon (mud pond), and
one of five liquid storage ponds containing a substantial amount of filtrate
(wastewater pond). The liquid storage ponds receive, in addition to the
filtrate, factory wastewaters discharged as a result of the production
process and such miscellaneous wastewaters as filter wash water, Mud House
and other factory clean-up water, free standing water draining from the lime
and mud ponds, etc. Gas samples from each of these three waste storage
ponds were analyzed to determine odor intensity, gas production rate, and
the chemical composition of the gas constituents.
Odor Intensity
In order to assign an accurate measure of intensity to the odors arising
from the various ponds, the following steps were taken: a) a collection
device was installed that permitted capture of pond off-gases, yet did not
interfere with the natural behavior of the pond in the area of the collector;
b) a unit of odor measurement that was scientifically sound and that could
be related to existing governmental regulations was agreed upon; and c) a
means of odor measurement that would produce a high degree of accuracy and
repeatability was developed.
Floating tents were designed and built, as shown in Figure 4, for each
of the three waste storage ponds to be tested. The design permits the tents
to float freely on the pond and also to penetrate the liquid surface suf-
ficiently to prevent outside air from entering at the base. Each tent was
tethered at one corner with a long rope to an anchor to aid in retrieving it
and to prevent it from becoming beached on shore. Vents in the top served
as gas relief ports and a hole near the base served as the sampling port.
The tents were periodically repositioned to: 1) avoid algae build-up
resulting from a greenhouse effect; and 2) restore them to their original
positions when moved by the wind.
Both the odor concentration unit and the odor measurement methods used
in this study are covered in the Minnesota Pollution Control Regulation (4),
one of the most thorough odor regulations in the United States. The regula-
tion states that "odor concentration unit shall mean the number of standard
cubic feet of odor-free air needed to dilute each cubic foot of contaminated
air so that at least 50 percent of the odor concentration test panel does
not detect any odor in the diluted mixture." The regulation further outlines
the procedures to be used for obtaining odor samples and presenting the
samples to a test panel.
The program called for the collection and analysis of samples at approxi-
mately two-week intervals to obtain a profile of activity as affected by
changes in temperature. Samples were drawn from the floating tents through
a short length of 6 mm (1/4-inch) Teflon tubing connected to the port at the
base of the tent and a two-liter Teflon sample bag. The samples were usually
drawn between 8 and 9 a.m. in order to facilitate same-day analysis. Odor
concentrations were determined according to ASTM D1391-57(5). The panel
testing procedure used was the method described by D. M. Benforado, et al
(6). A six-member panel of odor testers evaluated the samples. Panel
22
-------
PLAN
9"X6" POLYETHYLENE FLAP TO COVER
I" DIA. HOLES (TYPICALBOTH SIDES )
ENTIRE STRUCTURE COVERED WITH
4MIL POLYETHYLENE (MAKING GAS
TIGHT CONSTRUCTION)
1X2 WOOD BOARD (TYPICAL)
11/2" DIA. WOOD DOWELS (TYPICAL)
2X4 BOARD (TYPICAL)
I/2"DIA.HOLE INTO I/2"X6"XI2"
PLYWOOD, FOR SAMPLE PROBE
CHOLE COVERED WHEN NOT
IN USE)
90'
I DIA. HOLES
FLAP
J/2"X 9 3/4" SQR.
PLYWOOD
-.. •, .• «.•;•»•• •;•«•• .- ; .•..•".• ' • • •
.. •. ,> . ..«•,•,• ,*i »••.."•• '. - •'•»*• '
••'•-' •.'.'.''.... *.«/«.'- • •>>•;.'!*..••.••.' I •..'.«
POLYSTYRENE
FOAM (TYPICAL)
ELEVATION
(FRONT)
ELEVATION
(SIDE)
Figure 4^ Floating gas collector.
23
-------
members were first familiarized with the type of odor from each source with
samples of undiluted gas.
Various dilutions of the grab samples were prepared and presented to
the members of the odor panel in 100-ml syringes. The panel members smelled
the samples and recorded whether or not they detected an odor. After the
sample was tested, the panel member flushed the syringes with room air until
satisfied that no odor remained. Brief rest periods were provided during
which the panelists breathed filtered purified air to avoid olfactory fatigue
and retain sensitivity.
After the evaluation of a given sample, responses were tabulated and
the percent of positive responses plotted against dilution on log-normal
probability graph paper. The best straight line was drawn through the
points and the dilution corresponding to 50 percent was taken as the odor
concentration in odor units per standard cubic foot (ou/cf). In addition to
the test panel's determination of the odor concentration, the panel was
pooled to interpret odor quality. Such terms as "pig pen", "musty", "stale
river", etc., in combination with the numerical listing of odor concentration
units, provided a meaningful qualitative relationship.
Off-Gas Production
The lagoons are area sources due to their large surface area and ground-
line profile. The rate of gas emission from such a source and the concentra-
tion of constituents must be known in order to properly assess the magnitude
of the source.
Criteria for general gas collection devices were as follows. The
device had to: a) avoid interference with the natural biochemical action
in the ponds; b) adjust to fluctuating pond levels; c) be suitable for
dewatered and sloping pond surfaces; d) restrict entrance of outside air or
release of trapped gases to the atmosphere; e) provide a means of measuring
and recording the amount of off-gases generated; and f) be portable.
These criteria were met with an equipment arrangement as shown in
Figure 5. The equipment was installed prior to the spring thaw by cutting a
hole in the ice. Initially, gas production measurements were made on a
random basis; later, a regular schedule of daily examination and weekly
measurements was established. The gas sampling bag was taken to the lab
where gas volume was determined by fluid displacement. Before reinstalla-
tion of the bag, the collecting carboy was raised free of the pond surface
to permit displacement of accumulated surface material. The carboy was then
reset in its former position and the evacuated bag reconnected. The system
was disconnected for less than one hour during this procedure.
Odor Constituents
While the determination of the concentration of an odor quantifies its
presence, it reveals nothing of its chemical nature. It is obvious that
certain chemical compounds are responsible, either singularly or in combina-
tion, for the offensive nature of beet sugar waste pond off-gases.
24
-------
24"X24"X8" PLYWOOD
ENCLOSURE
TUBING
HINGE-
CO
CO
LJ
CC
GAS SAMPLING BAG
TEDLAR I8"XI8"X6"
15 LITER CAPACITY •
1/2"MALE THREAD X 3/8" HOSE ADAPTER
3/8"O.D. TEFLON TUBING(AS REQUIRED)
WATER LEVEL
FLOAT(TYP AS NEEDED)
•I9LITER PLASTIC CARBOY(WITH BOTTOM REMOVED)
APPROX. I"PIPE (TYP) DRIVEN INTO BOTTOM
Figure 5. Gas production sampler.
25
-------
An effort was made as a part of this study to ascertain what these chemical
constituents are.
It is known that certain compounds are detected by the human nose at
exceedingly low concentrations. Therefore, the investigation and identifi-
cation of the chemical constituents had to be intensive. In order to avoid
analyzing for every gas constituent that might have been present, a first
cut was made by analyzing some of the initial samples by gas chromatography
(GC). The GC scan revealed what chemical compounds were present, and to a
certain degree, their concentration levels. It also detected a number of
compounds below the threshold level needed for identification.
Subsequent gas sample analyses demonstrated that those chemical com-
pounds readily identified by the GC scan were not at concentrations high
enough to produce the associated odor levels. This reinforced the suspicion
that odorous compounds were present at below the identification threshold
levels for the GC instrument, but above the threshold levels detectable by
the human nose.
It was decided that concentrated odor gas samples should be obtained in
order to permit more positive detection and identification of the chemical
constituents of the gas through gas chromatography and mass spectrometry.
Several methods for obtaining concentrated gas samples are available and two
were selected to provide a margin of safety; condensation and adsorption on
activated charcoal.
Preparation of the condensation freeze trap was in accordance with ASTM
01605-60(7). A literature check provided a partial list of the chemical
constituents likely to be present and responsible for the offensive odors.
A check of their freezing points indicated that all could be readily frozen
out of an air stream at the -78.5°C temperature provided by an acetone and
dry ice mixture. The glass vacuum trap was suspended in an insulated vacuum
flask containing the dry ice and acetone mixture and 4 liters/minute (0.1413
cfm) of gas from the collection tent was drawn through the vacuum tube for
one hour. At the conclusion of the sampling period, the ends of the vacuum
tube were sealed and the tube with the frozen sample was placed in an insu-
lated chest at the same temperature for shipment to the laboratory for
analysis. The sampling procedure was repeated at each of the three ponds in
order to obtain three separate frozen gas samples.
After preparation of the activated charcoal adsorption column in the
laboratory according to ASTM D1354-60(8), the ends were sealed for transport
to the field. Sampling in the field consisted of unsealing both ends of the
adsorption column, connecting the column in line with the tube leading to
the collection tent and the vacuum pump, and drawing a gas sample through
the tube at the rate of 4 liters/min (0.1413 cfm) for one hour. Upon com- ,
pletion of the sampling, the ends were resealed on the adsorption column for
return shipment to the laboratory for analysis. This procedure was repeated
at each of the three ponds.
26
-------
Laboratory Procedures
The air samples collected by the three separate methods — charcoal
adsorption, low temperature condensation, and grab sampling with Teflon
bags—were analyzed by gas-liquid chromatography and wet chemical methods.
Charcoal Samples —
The charcoal was removed from the sampling tubes, and placed in a 22mm
x 300mm glass chromatography column with a porous glass bottom and Teflon
stopcock. Each charcoal sample was extracted by adding 100 ml of carbon
disulfide and allowing the sample to stand 20 minutes before draining. The
carbon disulfide leachate was immediately analyzed by gas-liquid chromatogra-
phy for mercaptans and sulfides.
Condensation Samples—
The sealed frozen condensate samples were removed from dry ice storage
and placed in a 35°C water bath. Each sample was allowed to reach equi-
librium temperature with the bath and then an air sample was removed with a
2.0 ml gas-tight GC syringe through a septum port on the sampling tube. The
extracted air sample was immediately analyzed by gas-liquid chromatography
for mercaptans and sulfides. The same procedure was repeated with the bath
temperature maintained at 100°C. This allowed for a higher concentration of
volatile components in the air space of the sampling tube.
Teflon Bag Samples--
Air samples were removed from the bags with a 2.0 ml gas-tight GC
syringe and analyzed immediately by gas-liquid chromatography for methane,
mercaptans, and sulfides. Hydrogen sulfide was determined by removing a
known volume of air with a 100-ml luger-lok syringe and analyzing the air
sample by the methylene blue photometric method.
27
-------
SECTION 7
RESULTS
The results are grouped into three areas. The first describes the
operation of the system components during the period of the study. The
second summarizes and interprets the data collected on the vacuum filter and
includes some mass balances. The third area presents the findings of the
post-campaign odor study.
SYSTEM OPERATION
Personnel
During the campaign period of this study, the beet transport water
system was operated by both factory-assigned personnel and by water system-
assigned personnel. Overall responsibility for the system rested with the
factory manager, although the Director of Technical Services, who also
provided project liaison, provided technical assistance in the operation of
the system. The rock catcher, beet washer, screens, grit chamber, flume
water pumps, pH control equipment, and ancillary equipment related to beet
handling were operated and maintained by factory-assigned personnel.
The clarifier, the Mud House, and the two lagoons were operated by
special personnel under the direction of the water system supervisor. There
were eleven people directly involved in the operation and maintenance of
this part of the system; the supervisor, his assistant, six operators, and
three helpers. The workday was divided into three 8-hour shifts that were
rotated every two weeks to allow the operators and helpers to work different
hours. (The operators and helpers are employed seasonally at MINN-DAK and
most are farmers in the area.) The supervisor and his assistant, unless
required by emergency situations or substituting for absent personnel,
worked only during the first shift. The main duties of these two permanent
MINN-DAK employees consisted of routine maintenance and repairs on the
equipment. Factory maintenance personnel were also available for emergencies
or for complicated equipment repairs.
Flume
The operation of the transport water system was predicated on the
maintenance of a pH around 10. Low pH in the transport water resulted in
foaming in the clarifier and foaming caused malfunctioning of the filtrate
meter. The formation of bacterial slimes that tended to depress the pH also
affected the filtration process by blinding the filter cloth. Maintenance
of pH at the proper level was accomplished by dumping lime rock in the flume
28
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with a payloader. This was complemented by the addition of milk of lime
when available. A more precise method for pH control of the flume water is
one of the areas that needs attention.
Whenever the pH dipped below the desired level of 10, the operators
requested the factory manage-r to add more lime. MINN-DAK's chief chemist
indicated that they had experienced problems in maintaining the desired pH
level during the 1976-77 campaign and that they were considering the use of
a biocide in the future to retard bacterial action.
Clarifier
During this study, the clarifier was operated by a single operator each
shift and sludge was pumped out continuously. At hourly intervals, the
operator recorded the pump's motor load which was normally kept between 30
and 36 percent of capacity. He also visually monitored the level of the
sludge surface and measured the settleable solids in the effluent with an
Imhoff cone. The operator controlled the volume of the underflow pumped out
of the clarifier by adjusting the setting on the pump. The underflow pumpage
rate was not meter-controlled, but was noted as low, average, or high.
Underflow density was controlled by changing the position of the suction
snout. When the solids level in the clarifier rose too fast, the operator
increased the pumping rate and raised the snout to increase the underflow
removal rate.
The clarifier operator's duties included raking floating frozen solids
out of the overflow trough. During periods of high foam and extremely low
temperatures, however, factory maintenance crews were called upon to break
out and remove frozen chunks from the clarifier. Operational problems were
experienced with the pump and pipeline from the clarifier to the Mud House.
The pump jammed on one occasion and the pipeline clogged several times due
to sand and gravel, an indication of problems in the operation of the grit
chamber (sand classifier) at the beet handling facility.
Mud House
At the Mud House, the hot lime mud from the factory and a portion of
the clarifier underflow were brought together in the mixing tank where these
two streams were blended by the action of a slow-moving coil. The level of
the slurry was allowed to reach about mid-tank before the contents were
allowed to -flow to one of the two vacuum filters. The operators then tried
to maintain this level by admitting all of the lime mud flow, and regulating
the amount of clarifier underflow as necessary to maintain the tank level.
This was done by operating the two gate valves on the clarifier underflow
pipeline located near the mixing tank.
The gate valves were positioned at either end of a tee; the line to the
mixing tank elbowed up while the bypass line to the lagoon elbowed down.
The Mud House operators estimated the amount of underflow required and
adjusted the valves accordingly. However, the operators did not know how
much, if any, underflow was entering the tank because the compartment was
closed on all sides and the steam created by the hot lime mud discharge made
29
-------
visual observation through small openings impossible. Also, the operators
could not see the amount of underflow being bypassed to the lagoon without
going outside the building.
The clarifier operator's main concern, as 'discussed earlier, was to
maintain the mud level at a manageable depth. To accomplish that, he
adjusted the percent motor load in the pump and the elevation of the suction
snout, thereby randomly changing the flow rate and the solids content in the
underflow. Since there was no telephone at the clarifier, and the distance
between the clarifier and the Mud House was about 365 meters (1,200 ft),
communications between these two installations took place only when a Mud
House employee drove to the clarifier. Consequently, the Mud House operators
were usually unaware of the conditions prevailing at the clarifier.
Almost all of the lime mud was taken into the mixing tank during the
campaign. The only time lime mud was bypassed was during protracted filter
shutdowns. On the other hand, most of the clarifier underflow was bypassed,
for a variety of reasons. In general, adequate controls were lacking and
underflow was often bypassed because less underflow resulted in fewer opera-
tional problems with the filters. Underflow was also bypassed whenever any
of the following occurred: blinding of the filter cloth, washing of the
filters, freezing of the cake in the pipeline due to extremely low temper-
atures, or breakdown of key equipment.
The vacuum filters were usually washed twice daily and sometimes three
or four times, depending on the degree of cloth blinding which, in turn,
depended upon the amount and quality of clarifier underflow admitted. Each
washing operation lasted about one hour, but this usually resulted in a
two-hour shutdown if the other filter was out of service. Shortly after the
campaign started, one of the filters suffered a major breakdown when the
blow-off unit was damaged, and it was out of service for more than a month,
waiting for replacement parts.
Some of the more common mechanical problems experienced in the operation
of the filters were agitator-bearing leaks and problems related to the
operation of the cake blow-off system. Less frequent and less complex
problems included plugging of the feed lines and loss of vacuum. Operational
problems attributed to process flows were caused mainly by the variability
in the characteristics of the clarifier underflow; volume, pH, solids content,
and sand content. In a few cases, the lime mud caused problems but, overall,
this flow was quite consistent, both in content and quantity. All of these
problems are documented in the Mud House Log Summary in Appendix B.
The sludge pumps operated alternately during the campaign. These pumps
were constantly under repair, mainly because of broken seals. At the end of
the campaign these pumps are usually taken apart and given a complete overr
haul consisting of repacking the pumps and resurfacing the cylinders.
Freezing of the filter cake in the sludge pipeline posed a particularly
difficult problem in the operation of the system. The length of the pipe-
line, the low velocity of the cake,, and the extremely cold North Dakota
winter all contributed to this problem.
30
-------
Lagoons
The sludge lagoons performed differently according to the character-
istics of the materials conveyed to them. At the filter cake lagoon, the
driest filter cake assumed a slight angle of repose—enough to permit free
water to flow toward the lower elevations and eventually to the dead end of
the drainage ditch. The wetter clarifier underflow sludge did not exhibit
an angle of repose and the total mass flowed rather freely throughout the
lagoon through an extensive network of canals carved in the mass by the
fresh discharge and by water released from previously deposited sludge. At
the far end of the lagoon, a culvert channelled the free water to the
drainage ditch. This culvert eventually became submerged in the sludge and
the water percolated through solids deposited in it. When the spring thaw
arrived, water surfaced and covered 80 to 90 percent of the lagoon. Because
of the dimensions of the lagoon, solar evaporation and slow seepage were the
only means available to eliminate this water cover. The water cover kept
this lagoon anaerobic, resulting in more objectionable odor conditions com-
pared to the filter cake storage lagoon.
VACUUM FILTRATION
In the following interpretation of the analytical data, temperature,
pH, dissolved COD, dissolved calcium, bulk density, percent solids, and
viscosity are discussed for the entire study period. The results for total
and dissolved solids, total COD, and total calcium are presented separately
for the 22-hour and the 8-hour sampling groups. The data are presented as
reported by the laboratory, without rounding.
Because pH values change with time due to bacterial action, pH data on
the composited samples are not meaningful, and only instantaneous pH measure-
ments are discussed here.
Temperature
Table 3 lists the average daily recorded temperatures of the
clarifier underflow, the lime mud, the filtrate, and the ambient air in the
Mud House. Daily high and low outdoor ambient temperatures are presented in
Table A-4 in the Appendix as supplemental data.
The clarifier underflow 'average temperature ranged between 7°C and
18°C. The effect of the North Dakota weather on the clarifier underflow is
reflected in the low temperature of the liquid, although it did not vary in
proportion to the extreme fluctuations in the outside temperature.
The average temperature of the lime mud ranged from a low of 36° C to a
high of 57°C, measured at the factory. It was then conveyed to the Mud
House via an elevated, insulated pipeline, and it can be assumed that the
lime mud was a few degrees cooler when it reached the Mud House.
The filtrate average temperature ranged from a low of 19°C to a
high of 31°C. The contribution of lime mud to the filtrate is shown by
the relatively high temperature of the filtrate. This contribution
- 31
-------
TABLE 3. TEMPERATURE AND pH DATA
DATE
11-9-76
11-10-76
11-12-76
11-14-76
11-15-76
11-16-76
11-17-76
11-18-76
11-19-76
11-21-76
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-28-76
11-29-76
11-30-76
12-1-76
12-2-76
12-3-76
12-5-76
12-6-76
12-7-76
12-8-76
12-9-76
12-10-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-26-76
12-28-76
12-29-76
12-30-76
12-31-76
1-2-77
1-3-77
1-4-77
1-5-77
1-6-77
1-7-77*
1-8-77*
1-9-77*
1-10-77*
1-11-77*
1-12-77*
1-13-77*
Clarifier
Underflow
Tenp. pH**
•C
7
8
12
12
11
10
9
13
15
9
10
14
13
12
10
18
16
14
13
12
11
14
14
11
12
12
11
15
12
14
17
17
15
12
13
13
15
14
13
13
11
13
13
14
13
10
10
10
8
13
11
12
13
12
14
14
._
—
«
7.0
7.3
8.2
10.2
9.2
8.7
7.2
8.1
7.5
8.5 '
10.0
8.8
7.7
7.7
7.6
8.9
7.8
7.7
7.9
8.7
7.8
7.9
7.8
7.0
6.3
6.1
6.4 (10)
6.8
6.6
6.5
5.0
4.8
4.8
5.0
5.0
6.0
5.9
4.8
4.7
6.6
6.6
6.1
5.5
5.3
5.7
—
6.7
—
--
5.6
5.9
5.5
6.1
Lime Hud
Temp.
•C
..
~
«
--
--
~
—
--
--
—
--
52
50
42
43
45
45
41
51
57
56
54
54
52
53
52
53
54
54
54
54
S3
53
53
51
47
50
49
50
50
47
46
43
42
45
43
47
46
38
48
—
36
—
47
—
Hud House
Filtrate Ambient
leap.
"C
24
25
21
26
25
24
26
26
26
30
26
29
24
21
23
30
29
28
28
27
28
30
27
27
27
28
25
31
29
28
30
30
29
30
25
27
27
28
31
26
25
27
29
30
30
27
26
26
22
26
25
27
19
28
28
29
pH**
__
—
.-
10.2
6.8
8.8
7.1
7.0
6.8
8.9
8.5
7.2
6.9
8.3
6.8
6.1
7.6
7.7
6.6
6.8
6.8
6.8
7.9
6.9
6.5
6.5
6.9
6.5
6.9
6.8 (9.1)
6.6
6.3
6.4
6.5
7.0
6.2
6.7
5.9
6.5
6.8
9.6
7.2
6.6
6.9
6.4
6.4
5.7
6.5
—
9.3
—
—
7.4
8.7
8.4
8.1
Temp.
"C
16
16
16
16
17
15
16
18
16
17
16
13
16
17
16
22
16
14
13
14
17
15
14
14
14
15
14
16
18
14
15
15
15
13
22
22
21
21
17
17
11
13
13
12
17
15
16
16
13
12
13
15
11
11
17
17
* Special monitoring period; 8-hour composites
** pH of composite samples reflecting changes due to biological action.
Values in parentheses are instantaneous.
32
-------
cannot be quantified without a knowledge of the specific heats of the liquids
and slurries, heat losses in the Mud House, and other necessary data.
The work plan did not include instantaneous pH measurements by the Mud
House operators because of anticipated problems with pH meter operation and
maintenance. More grab samples and/or provision for sample preservation
during collection and before analysis would have provided useful data, but
were not regarded as feasible within the scope of the study.
During a 4-hour period on December 14, 1976, five hourly grab samples
were taken and the pH measured within 15 minutes of collection. The pH
values ranged from 9.6 to 10.3 for the clarifier underflow and from 8.8 to
9.4 for the filtrate. These values indicate a decrease of two to four pH
units due to storage of the samples during collection and before analysis.
The instantaneous pH measurements are presented in Table A-3 of the Appendix.
Solids
Table 4 presents data on the total and volatile solids contents of the
clarifier underflow, lime mud, filtrate, and filter cake. The total and
volatile solids data for the lime mud and filter cake have been corrected
for the bulk densities.
The clarifier underflow total solids content ranged from a low of 27.8
g/1 to a high of 207 g/1. The high and low concentrations appear to have
occurred in groups of five or more days at a time. The 8-hour samples had a
mean total solids content of 79 g/1. Wide variations in the data throughout
the study period reflect the effect of the sludge withdrawal method, the
rate being continually adjusted by the clarifier operator.
The volatile solids content of the clarifier underflow showed a low of
10.8 g/1 and a high of 36.4 g/1. The mean volatile solids content of the
8-hour samples was 20 g/1. The volatile solids constituted 20 to 25 percent
of the total solids in the clarifier underflow.
The total solids in the lime mud ranged from a low of 443 g/1 to a high
of 774 g/1. The mean concentration for the 8-hour samples was 680 g/1. The
data appear to be evenly dispersed throughout the data collection period
with both high and low values occurring toward the end of the campaign.
Very few problems were encountered with variations in the lime mud flow due
to relatively steady conditions in the factory where this material originated.
The volatile solids content of the lime mud exhibited a low of 56.1 g/1
and a high of 110 g/1. The mean concentration for the 8-hour samples was 77
g/1. The data generally show higher values occurring in the first half of
the period, and lower values during the last half of the period, but these
differences are minor. The volatile solid fraction was about 12 percent of
the total solids.'
33
-------
TABLE It. TOTAL AND VOLATILE SOLIDS DATA
.HATS
11-14-76
11-15-76
11-16-76
11-17-76
11-18-76
11-19-76
11-21-76
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-28-76
11-29-76
11-30-76
12-1-76
12-2-76
12-3-76
12-5-76
12-6-76
12-7-76
12-8-76
12-9-76
12-10-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
1-2-77
1-3-77
1-4-77
1-5-77
1-7-77*
1-10-77*
1-11-77*
1-12-77*
1-13-77*
Clarifier
Underflow
Total Vol.
8/1 8/1
49.1
61.9
90.9
119
115
78.5
49.4
119
181
161
80.4
110
191
135
113
168
156
207
78.6
73.5
96.3
70.7
53.2
27.8
85.6
35.3
33.5
162
143
119
28.6
53.2
155
175
74.7
97.9
97
108
64.9
95.3
84.6
110
112
68.5
84.9
32.8
74.7
80.6
77.9
127
16
14.9
19.2
22
24.7
18.5
15.5
22.4
29.1
25.4
14.2
19.1
32.9
29.1
23.5
32.4
29.1
35.3
19.6
18.6
22.3
18.8
15.8
10.8
23
13.5
12.6
36.4
30
23.4
11.7
16.6
32.2
33.2
19.6
23.1
27.2
23.7
18.1
27.2
24.7
24.4
28.8
17.9
22.2
12.8
19.7
19.4
19.7
25.8
Line
Total
g/1
731
686
753
708
—
669
724
720
627
660
585
631
597
647
605
682
765
716
711
705
742
745
710
729
681
689
769
704
695
703
703
664
607
677
672
648
688
680
705
702
443
576
610
651
603
664
613
630
730
774
Hud
Vol.
g/1
110
95
107
107
—
108
103
102
89.6
88.3
76
86.9
92.6
88.4
91.2
86.5
109
99.6
85
96.6
92.8
92.6
101
100
81.2
81.8
78.2
78.5
85.7
81.4
79.6
86.7
73.1
74.9
85.5
86
93
82.0
76.2
82.2
56.1
65.7
83.5
85.7
80
76.3
64.4
65.4
83.7
96
Filtrate
Total Vol.
g/1 g/1
37.1
29.2
22.6
34.5
42.1
41.7
55.5
33.6
26.5
24.8
25.3
42.6
53.2
111
105
32.6
39.4
37.5
37.7
46.6
36.3
34.2
38.4
62.3
33.1
24.1
38.8
22.4
29.2
27.2
28.9
22.9
29.5
24.1
29.4
38.4
40.9
30.6
38.6
28.8
34.4
19.5
29.9
29.3
26.9
33.3
21.1
29.1
33.5
31.3
33.7
23.8
19.7
30.6
38.4
37.1
40.1
30.1
22.3
18.9
20.5
27.8
42.5
54
48.2
25.2
34.2
32.5
31.9
38
30.1
26.5
30.6
31.5
27.3
15.6
26.6
17.3
24.7
23.0
22.2
19.4
26.6
20.5
26.2
32.9
33.5
24.5
23.7
21.0
30.8
16.1
26.9
26.3
24
30
18.2
25.8
30
27.8
Filter
Cake
Total
g/1
__
—
846
825
822
823
800
822
845
804
822
830
896
852
854
839
859
902
849
797
892
936
855
839
838
849
873
818
799
805
870
824
820
854
860
869
856
839
919
898
854
841
814
855
792
784
881
879
879
847
Vol.
g/1
..
—
96.4
102
106
106
98.2
98.9
102
89.9
93.2
95.3
111
103
108
96.8
105
107
89.3
92.9
93.4
95.1
95.3
92.4
88.6
93.4
87.1
83.1
95.1
81.8
87
91
84.5
89
87.8
90.4
96.5
86.7
85.6
93.5
83.0
84
95.2
96.1
88
89.7
76.4
83.7
89.7
97.1
Special monitoring period; 8-hour composites
34
-------
The total solids content of the filtrate ranged from a low of 19.5 g/1
to a high of 111 g/1. The mean concentration for the 8-hour samples was 30
g/1. With the exception of two very high values occurring on consecutive
days, the data comprise a relatively narrow range of values. On November 29
and 30, 1976, problems were experienced with the clarifier pump and the
underflow pipeline. It is suspected that the dilute clarifier underflow
admitted to the mixing tank during this period caused a dirty filtrate
because the low-solids slurry could not be efficiently filtered.
The volatile solids content of the filtrate exhibited a low value of
15.6 g/1 and a high of 54 g/1. The mean concentration was 26 g/1 for the
8-hour samples. The data show a relatively narrow range of values. The
volatile fraction of the filtrate constituted 75 to 90 percent of the total
solids.
The total solids content of the filter cake exhibited a low value of
784 g/1 and a high value of 936 g/1. The mean value for the 8-hour samples
was 850 g/1. The data are generally consistent, indicative of uniform
performance by the filters.
The volatile solids content of the filter cake exhibited a low value of
76.4 g/1 and a high value of 111 g/1. The 8-hour samples had a mean volatile
solids content of 87 g/1. The data show the same even distribution and
narrow range of values as the total solids content. The volatile fraction
constituted about 10 percent of the total solids in the filter cake.
Chemical Oxygen Demand (COD)
Table 5 lists the daily total COD values of the clarifier underflow,
lime mud, filtrate, and filter cake. Dissolved COD values, also given in
Table 5, were measured weekly.
The concentration of total COD in the clarifier underflow ranged from
13,500 mg/1 to 60,300 mg/1. The mean value was 30,000 mg/1 for the 8-hour
samples. The expected increase in total COD due to beet deterioration was
not readily evident in the data distribution, since high and low values were
measured throughout the study.
The concentration of dissolved COD in the clarifier underflow exhibited
a low of 7,450 mg/1 and a high of 24,900 mg/1, with a mean of 16,000 mg/1.
The general trend is toward higher COD values with the progress of the
campaign. The mean total COD of the samples also analyzed for dissolved COD
was 37,000 mg/1.
The total COD of the lime mud ranged from 26,700 mg/1 to 127,000 mg/1.
The mean was 51,000 mg/1 for the 8-hour samples. The data show high values
of total COD in the lime mud during the first half of the study and lower
values for the second half. Changes in the carbonation process at the
factory are believed to be responsible for this change.
The dissolved COD of the lime mud showed a low concentration of 22,100
mg/1 and a high of 57,500 mg/1, with a mean concentration of 29,000 mg/1.
35
-------
TABLE 5. TOTAL AM) DISSOLVED COD DATA
Clarifier
Underflow
DATE
11-14-76
11-15-76
11-16-76
11-17-76
U-18-76
11-19-76
11-21-76
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-28-76
11-29-76
11-30-76
12-1-76
12-2-76
12-3-76
12-5-76
12-6-76
12-7-76
12-8-76
12-9-76
12-10-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-26-76
12-28-76
12-29-76
12-30-76
12-31-76
1-2-77
1-3-77
1-4-77
1-5-77
1-7-77*
1-10-77*
1-11-77*
1-12-77*
1-13-77*
Total
Bg/l
17,800
21,500
26,800
42,300
33,200
28,900
13,500
27,500
46,500
25,400
23,200
30,000
49,400
44,400
60,300
46,400
44,300
47,800
36,200
33,500
35,700
30,500
26,700
25,500
31,000
26,400
51,400
42,800
38,400
16,600
32,800
48,300
45,800
34,600
38,600
43,400
34,000
46,400
42,700
43,500
44,900
46,600
29,900
45,800
15,600
29,200
40,800
28,800
37,100
Dis.
Bg/1
~
—
7,450
—
«
—
14,100
—
—
—
—
~
9,320
~
~
~
—
«
13,400
—
~
~
—
18,500
—
~
—
«
—
24,900
--
—
—
—
—
~
—
--
—
~
18,500
~
~
—
—
24,600
—
Lime
Total
Bg/1
111.000
114,000
85,300
80,700
54,100
69,200
44,300
114,000
127,000
78,200
58,700
58,800
97,200
83,800
95,300
63,400
117,500
103,000
95,200
85,000
95,500
95,400
109,000
112,000
75,100
83,500
66,300
79,700
51,200
66,900
69,750
67,600
65,600
60,700
71,900
73,600
53,900
52,700
40,200
49,300
48,400
59,300
26,700
42,400
48,200
43,000
43,000
58,300
61,500
Hud
Dis.
«g/l
__
«
—
22,100
—
—
—
57,500
—
—
—
—
—
53,000
—
--
—
—
—
51,300
—
—
—
—
33,100
—
—
—
—
—
42,200
—
«
—
«
—
—
—
—
—
—
25,900
«
—
—
—
25,700
—
Filtrate
Total Dis.
mg/1 og/1
35,900
26,300
21,000
32,700
40,600
«
—
81,500
53,700
91,600
17,600
37,500
56,000
~
51,600
25,000
45,900
46,400
43,500
48,300
42,900
37,600
41,000
110,000
30,400
39,100
35,250
38,100
35,700
36,800
36,300
41,000
37,300
29,900
44,400
46,200
38,300
35,700
36,100
51,900
21,600
32,200
46,100
29,800
32,800
26,800
30,800
36,900
34,700
«
—
33,100
—
—
~
32,500
—
—
—
—
—
~
—
~
— •
~
—
44,400
~
~
—
—
25,500
--
—
~
~
--
28,200
~
—
—
~
—
~
«
~
—
~
35,200
—
—
—
~
32,100
«
Filter
Cake
Total Dis.
Bg/1 Bg/1
90,200
149,000
75,000
91,000
73,100
93,000
54,500
121,000
148,000
100,000
87,300
89,100
116,000
126,000
114,000
92,000
119,000
108,000
116,500
121,000
102,000
81,300
108,000
94,600
73,100
88,000
82,300
82,500
73,700
82,600
64,300
60,500
67,000
62,200
85,600
98,300
57,600
64,000
69,800
81,800
74,600
74,300
59,500
66,500
64,000
66 , 700
52,150
65,800
63,300
„
—
—
24,800
—
--
—
20,900
—
--
—
—
—
43,700
—
~
—
--
—
44,500
—
•-
—
~
22,100
—
—
--
--
--
24,500
~
—
—
—
«
—
--
--
—
—
21,800
--
—
—
—
16,900
~
* Special monitoring period; 8-hour composite!
36
-------
The dissolved COD values are evenly distributed throughout the study period.
The mean total COD of the samples from which the dissolved values were
obtained was 76,000 mg/1.
The total COD of the filtrate exhibited a low concentration of
17,600 mg/1 and a high concentration of 110,000 mg/1. The mean concentration
was 32,000 mg/1 for the 8-hour samples. The distribution of values appears
uniform with respect to time. As with the lime mud, higher values of total
COD in the filtrate occurred in the first half of the study period and lower
values in the second half.
The dissolved COD of the filtrate exhibited a low concentration of
25,500 mg/1 and a high concentration of 44,400 mg/1, with a mean concen-
tration of 33,000 mg/1. The mean total COD of the samples from which the
dissolved values were determined was 42,000 mg/1. It may be noted that in
the case of low total COD values (11-17-76, 1-3-77, and 1-11-77) the corre-
sponding dissolved COD values exceeded the total values. This is attributed
to analytical and sampling errors.
The total COD of the filter cake varied from a low of 52,200
mg/1 to a high of 149,000 mg/1. The mean value was 62,000 mg/1 for the
8-hour samples. The distribution of values shows that, as with the lime mud
and filtrate COD values, higher concentrations of total COD prevailed during
the first half of the data collection period and lower concentrations during
the last half.
The dissolved COD of the filter cake had a low concentration of
16,900 mg/1, a high concentration of 44,500 mg/1, and a mean concentration
of 27,000 mg/1. The total COD of the samples analyzed for dissolved COD had
a mean value of 90,000 mg/1. The data show generally higher dissolved COD
values during the first half of the study period and lower values toward the
end, with the lowest dissolved COD value corresponding to the lowest total
COD value.
Calcium
Measurements of calcium, as Ca, are presented in Table 6, and
include both total and dissolved concentrations of calcium in the clarifier
underflow, lime mud, filtrate, and filter cake.
The total calcium concentration of the clarifier underflow had a
low value of 814 mg/1 and a high value of 7,310 mg/1. The means were 3,200
mg/1 for the 22-hour samples and 1,400 mg/1 for the 8-hour samples. The
only pattern discernible is that groupings of three to five consecutive
measurements are in the same range of concentration. This is attributed to
batch liming of the flume to control pH.
The dissolved calcium concentration of the clarifier underflow
exhibited a low of 536 mg/1, a high of 2,000 mg/1, and a mean value of 1,000
mg/1. The high dissolved calcium concentration corresponded to the high
total calcium value; the dissolved fraction constituted about one third of
the total calcium.
37
-------
TABLE 6. TOTAL AND DISSOLVED CALCIUM DATA
DATE
11-16-76
11-17-76
11-18-76
11-19-76
11-21-76
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-29-76
11-30-76
12-1-76
12-2-76
12-3-76
12-5-76
12-6-76
12-7-76
12-8-76
12-9-76
12-10-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
1-2-77
1-3-77
1-4-77
1-5-77
'1-7-77*
1-10-77*
1-11-77*
1-12-77*
1-13-77*
Clarifier
Underflow
Total Dis.
ng/1 "g/1
4,160
4,570
4,141
3,380
1,700
3,930
5,900
4,080
3,680
4,170
4,710
3,510
4,905
5,160
6,650
3,870
3,850
3,710
3,260
3,010
1,880
3,930
1,640
1,910
7,310
6,170
4,700
814
928
1,900
1,700
1.240
2,070
2,460
2,080
985
1,060
2,035
2,080
2,030
1,790
1,210
1,300
1,080
1,460
1,410
1,260
1,890
__
--
728
664
657
851
928
785
593
652
961
1,070
1,365
1,180
843
1,440
1,365
1,390
1,340
1,210
1,310
1,610
1,240
1,290
2,000
1,650
1,640
807
600
921
785
911
1,710
1,580
1,240
635
536
1,185
1,120
1,010
871
643
578
757
721
585
600
797
Lime Hud
Total Dis.
Bg/1 »g/l
199,000
222,000
104,000
205,000
228,000
237,000
197,000
201,000
192,000
215,000
185,000
208,000
241,000
252,000
234,000
224,000
266,000
224,000
247,000
226,000
219,000
206,000
215,000
242,500
231,000
229,000
209,000
231,000
219,000
199,000
227,000
224,000
218,000
226,500
229,000
227,000
211,000
151,000
163,000
198,000
201,000
208,000
194.000
223,000
207,000
207,000
234,000
246,000
—
1,860
1,760
1,210
2,670
785
952
1,240
1,110
1,330
1,490
1,050
1,000
807
864
700
1,980
835
1,060
1,060
571
835
1,700
543
578
478
571
1,185
571
571
743
628
700
650
735
614
1,060
618
528
871
1,520
785
468
514
543
528
628
Filtrate
Total
•g/1
657
942
2,120
1,535
2,690
885
1,357
1,590
1,640
4,970
5,310
—
3,940
1,370
1,435
1,810
2,910
1,480
2,330
2,105
—
1,470
2,860
4,090
1,510
1,310
1,190
2,010
885
757
650
771
1,480
2,330
1,940
2,520
2,570
907
971
850
821
778
800
843
750
935
764
885
Dis.
mg/1
—
871
950
657
942
650
862
600
1,280
1,120
1,640
1,080
1,020
814
1,000
1,100
1,090
1,190
1,340
1,660
1,290
1,180
1,360
1,555
1,190
1,190
1,010
835
740
607
764
1,120
1,210
878
764
743
843
878
850
821
728
728
564
600
621
628
835
Filter
Cake
Total
ng/1
209,000
227,000
267,000
256,000
261,000
220,000
224,000
213,000
230,000
227,000
276,000
289,000
260 , 000
251,000
257,000
270,000
264,000
293,000
280,000
280,000
258,000
245,000
286,000
279,000
239,000
219,000
232,000
288,000
224,000
237,000
223,000
271,000
259,000
247,000
247,000
300,000
282,000
276,000
250,000
272,000
255,000
247,000
267.000
263,000
276,000
296,000
260,000
242,000
Dis.
og/1
--
2,180
2,430
3,050
1,590
1,960
1,710
2,330
1,570
—
2,780
1,330
2,860
2,800
3,105
--
2,400
1,980
1,840
2,335
2,830
2,200
2,330
1,890
2,250
1,950
1,730
2,000
2,580
928
2,370
2,240
1,750
2,870
1,035
1,510
2,000
1,090
904
2,145
3,220
2.230
571
657
634
743
1,030
* Special monitoring period; 8-hour composites
38
-------
The lime mud had a low total calcium content of 104,000 mg/1 and a high
total calcium content of 266,000 mg/1. The mean values were 210,000 mg/1
for the 22-hour samples and 220,000 mg/1 for the 8-hour samples. The values
were evenly distributed throughout the study period.
The dissolved calcium content of the lime mud ranged from a low
concentration of 468 mg/1 to a high of 2,670 mg/1, with a mean value of
1,000 mg/1. The concentration distribution begins with higher values and
then diminishes as the campaign progressed, interspersed with occasional
high values. The dissolved fraction was generally less than one percent of
the total calcium.
The filtrate exhibited a low total calcium concentration of 650
mg/1 and a high concentration of 5,310 mg/1. The mean values were 1,800
mg/1 for the 22-hour samples and 840 mg/1 for the 8-hour samples. The
spread of values was very wide, with the lowest value being only about 12
percent of the highest value.
The dissolved calcium content of the filtrate exhibited a low value of
564 mg/1, a high value of 1,660 mg/1, and a mean value of 1,000 mg/1. For
total calcium concentrations up to about 1,200 mg/1, the dissolved calcium
ranged from 70 percent to 100 percent of the total. On the average, the
dissolved calcium constituted about 55 percent of the total calcium present.
The filter cake had a total calcium concentration ranging from a low
value of 209,000 mg/1 to a high of 300,000 mg/1. The mean concentrations
were 260,000 mg/1 for the 22-hour samples and 270,000 mg/1 for the 8-hour
samples. The values were evenly distributed and consistent with the distri-
bution of the waste lime calcium concentrations.
The dissolved calcium of the filter cake had a low value of 571 mg/1, a
high value of 3,220 mg/1, and a mean value of 2,100 mg/1. With the exception
of the substantially lower values measured on the 8-hour samples, the concen-
tration distribution appears uniform throughout the study period.
Bulk Density and Percent Solids
Table 7 presents the bulk density and percent solids data for the
clarifier underflow, lime mud, filter cake, and cake storage samples. The
cake storage data are presented for comparison with the filter cake data.
The cake storage samples are essentially the same as the filter cake samples
except that water was added to facilitate pumping of the cake to the storage
lagoon. The filtrate, because it is essentially water with a relatively low
solids content, was not analyzed for bulk density. The bulk density of
samples was determined gravimetrically. The percent solids data show the
weight of dry solids per 100 grams of wet sample.
The bulk density of the clarifier underflow ranged from 0.99 to 1.10
g/ml, with a mean value of 1.04 g/ml for both groups of samples. The varia-
tion in bulk density is related to the amount and type of solids present in
the sample and the distribution of values appears to be relatively even
throughout the study, with a few exceptions. About 80 percent of the values
39
-------
TABLE 7. BULK DENSITY AMD PERCENT SOLIDS DATA **
Clarifier
Underflow
DATE
11-14-76
11-15-76
11-16-76
11-17-76
11-18-76
11-19-76
11-21-76
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-28-76
11-29-76
11-30-76
12-1-76
12-2-76
12-3-76
12-5-76
12-6-76
12-7-76
12-8-76
12-9-76
12-10-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
-2-77
-3-77
-4-77
-5-77
-7-77*
-10-77*
-11-77*
1-12-77*
1-13-77*
g/«l
1.04
1.02
1.05
1.03
1.03
1.05
1.03
1.01
1.01
1.04
1.01
1.04
1.03
1.03
1.04
1.00
0.99
1.03
1.02
1.04
1.04
1.04
1.02
1.02
1.05
1.03
1.01
1.03
1.07
1.07
1.02
1.03
1.09
1.10
1.05
1.06
1.06
1.07
1.04
1.05
1.05
1.04
1.06
1.06
1.04
1.03
1.02
1.03
1.04
1.05
1.06
X
4.7
6.1
8.7
11.6
11.2
7.5
4.8
11.8
17.9
15.5
8.0
10.6
18.5
13.1
10.9
16.8
15.8
20.1
7.7
7.1
9.3
6.8
5.2
2.7
8.2
3.4
3.3
15.7
13.4
11.1
2.8
5.2
14.2
15.9
7.1
9.2
9.2
10.1
6.2
9.1
8.1
9.5
10.4
10.6
6 6
8.2
3.2
7.3
7.8
7.4
12.0
Line Mud
K/»l
1.41
1.42
1.48
1.46
1.39
1.39
1.41
1.41
1.37
1.39
1.33
1.39
1.38
1.37
1.36
1.40
1.45
1.43
1.41
1.42
1.44
1.44
1.42
1.43
1.40
1.40
1.44
1.43
1.42
1.42
1.41
1.39
1.37
1.40
1.40
1.38
1.41
1.41
1.43
1.42
1.26
1.30
1.35
1.36
1.39
1.36
1.40
1.37
1.38
1.44
1.46
X
51.8
48.3
50.9
48.5
--
48.1
51.3
51.1
45.8
47.5
44.0
45.4
43.3
47.2
44.5
48.7
52.8
50.1
50.4
49.6
51.5
51.7
50.0
51.0
48.6
49.2
53.4
49.2
48.9
49.5
49.9
47.8
44.3
48.4
48.0
47.0
48.8
48.2
49.3
49.4
35.2
38.4
42.7
44.9
46.8
44.3
47.4
44.7
45.7
50.7
53.0
Filter
Cake
8/»l
1.49
1.50
1.48
J.47
1.47
1.48
1.48
1.49
1.47
1.49
1.49
1.52
1.49
1.50
1.50
1.51
1.52
1.52
1.48
1.54
1.53
1.51
1.49
1.50
1.51
1.54
1.50
1.48
1.49
1.53
1.49
1.49
1.53
1.53
1.54
1.52
1.52
1.55
1.54
1.52
1.49
1.51
1.48
1.50
1.48
1.48
1.54
1.54
1.53
1.52
X
__
—
56.4
55.7
55.9
56.0
54.1
55.5
56.7
54.7
55.2
55.7
58.9
57.2
56.9
55.9
56.9
59.3
55.9
53.9
57.9
61.2
56.6
56.3
55.9
56.2
56.7
54.5
54.0
54.0
56.9
55 "3
55.0
55.8
56.2
56.4
56.3
55.2
59.3
58.3
56.2
54.2
55.7
55.0
57.0
53.5
53.0
57.2
57.1
57.5
55.7
Cake
Storage
8/nl X
1.51
1.46
1.42
1.56
1.45
1.47
1.46
1.45
1.45
1.44
1.47
1.45
1.48
1.46
1.44
1.47
1.48
1.51
1.48
1.52
1.51
1.52
1.50
1.48
1.49
1.49
1.50
1.48
1.48
1.47
1.51
1.47
1.47
1.49
1.49
1.48
1.51
1.49
1.51
1.49
1.51
1.47
1.50
1.46
1.48
1.47
1.48
1.53
1.50
1.50
1.49
56.0
55.2
55.8
56.1
55.4
54.9
56.0
53.9
53.9
53.8
54.0
53.2
54.7
54.7
52.4
54.1
54.8
56.2
58.2
56.1
57.0
56.6
55.6
52.7
54.9
56.6
53.1
53.8
54.3
52.9
55.9
53.7
52.7
53.8
54.2
53.7
54.6
55.1
55.2
55.8
55.5
51.4
53.8
52.0
53.3
52.4
53.6
56.8
54.9
55.8
54.8
* Special monitoring period; 8-hour composites
** Percent solids by weight
40
-------
ranged between 1.02 and 1.06 g/ml.
The percent solids of the clarifier underflow ranged from a low value
of 2.7 percent to a high of 20.1 percent with a mean value of 9.6 percent.
The data generally show higher values during the initial part of the data
collection period and lower values toward the end of the campaign.
The bulk density of the lime mud ranged from a low value of 1.26 to a
high of 1.48 g/ml, with a mean value of 1.4 g/ml. The bulk density of the
lime mud varied within a narrow range of values throughout the study period.
The percent solids of the lime mud had a low value of 35.2 percent, a
high value of 53.4 percent, and a mean value of 48 percent. The percent
solids data of the lime mud samples agree well with the bulk density data,
showing only slight variation with respect to time.
The bulk density of the filter cake had a low value of 1.47 g/ml, a
high value of 1.55 g/ml, and a mean value of 1.50 g/ml. The filter cake
bulk density varied little throughout the study period; all values were
within 5 percent of one another.
The percent solids of the filter cake had a low value of 53 percent, a
high value of 61.2 percent, and a mean value of 56 percent. All of the
values occurred within a narrow range, although not as narrow as the bulk
density values.
The bulk density of the cake storage samples ranged from a low value of
1.42 to a high of 1.52 g/ml, with a mean value of 1.48 g/ml. The data are
evenly distributed with respect to time. The added water in the cake storage
samples reduced the solids content by about 3 percent compared to the filter
cake samples.
Viscosity
A limited number of viscosity measurements were made by MINN-DAK on
clarifier underflow, lime mud, filter cake, and filter cake storage samples.
The data are presented in Table A-3 of the Appendix, with the cake storage
samples omitted because of their limited value.
It was concluded from the viscosity measurements that the samples
tested were non-Newtonian fluids exhibiting changes in viscosity with respect
to duration and rate of shear application. These changes were attributed to
non-symmetrical composition and to cohesiveness within the slurries. Non-
symmetrical composition of the samples refers to the presence of large
molecules, colloids, and suspended solids.
The clarifier underflow and the lime mud samples, for which the viscos-
ity measurements have meaning, had average viscosities of 40 and 1,200
centipoises, respectively. The filter cake viscosity values averaged 27,000
centipoises. The viscosity measurements were made at temperatures of from
22°C to 26°C.
41
-------
The bulk density and percent solids data, with the exception of the
clarifier underflow, were quite consistent throughout the data collection
period. They also show the negligible contribution of solids from the
clarifier underflow to the filter cake solids.
Typical Flow Rates and Mass Balances
Figure 6 depicts a typical flow balance for the Mud House operation.
The balance was constructed using actual operating data, measured flows,
estimated flows based on assumed values from observed operations, and adjust-
ments of the actual data.
In the balancing procedure, the filtrate flow rate was given the highest
reliability. Following, in order of decreasing reliability, were the calcu-
lated filter cake .and the lime mud flow rates. While the total underflow
out of the clarifier could be determined with a high degree of confidence,
its distribution between the mixing tank and the bypass flows could be
determined only by balancing the filtration process input and output flows.
As noted above, the methods employed by the operators to control the amount
of clarifier underflow admitted into the mixing tank did not give reliable
estimates of flow rates. For this reason, the flow rate of the clarifier
underflow into the mixing tank was made to fit the balancing equation.
The filtrate flow rate was obtained from actual data recorded on the
log sheets. However, faulty data due to liquid aeration and other opera-
tional problems produced wide fluctuations in the instantaneous flow meter
readings. A careful evaluation of the data was therefore required to screen
out spurious results and to select those operating periods that were judged
to have produced reliable data. The filtrate flow rate for each day for
which reliable data were obtained was calculated and entered, including the
operating hours, in the Mud House log summary. These flow data are presented
in Table A-l of the Appendix. An actual average flow rate of 166 cu in/day
(30 gpm) was obtained.
The sludge pump stroke counters installed to measure the rate of filter
cake production did not yield useful results. When the operating logs were
reviewed, it was determined that each operator exercised different criteria
to estimate the effective stroke length of the pump cylinder. Some operators
measured and recorded the distance to be subtracted from the full stroke
while others estimated and recorded the effective stroke. Consequently, the
stroke counter data were discarded because they were judged to be inconsis-
tent.
The filter cake production rate was calculated using the filter dimen-
sions, rotational speed, and observed typical filter cake thickness as
follows:
Filtering area per revolution: 63 sq
Rotational speed: 1 revolution/2.5 md
m
Rotational speed: 1 revolution/2.5 min
Cake thickness: 1.05 cm
Production rate = (63 sq m/rev)(0.0105 m)(1 rev/2.5 min)(1440 min/day)
= 382 cu m/day (70 gpm)
42
-------
LIME MUD
491 CU.M/DAY
CLARIFIER
UNDERFLOW
981 CU.M/DAY
MIXING
TANK
INPUT
BY-PASS TO
55CU.M
/DAY
LAGOON
926 CU. M/DAY
FILTER FEED
546 CU. M DAY
i
VACUUM
FILTER
FILTRATE
164 CU.M/DAY
FILTER CAKE
382 CU. M/DAY
Figure 6. Typical process flows.
43
-------
The thickness of the filter cake varied between 0.6 cm and 1.6 cm (1/4
to 5/8 in). A variation of 0.15 cm (1/16 in) in the thickness of the cake
produces a theoretical variation in the flow rate of about 55 cu m/day (10
gpm) •
An attempt was made to calculate a theoretical rate of flow for lime
mud using lime production and waste lime calcium concentration data for a
six-day period as follows:
Lime production: 93,700 kg/day, as CaO
Waste lime calcium concentration: 220 g/1, as Ca
Calculated lime concentration: 308 kg/cu m, as CaO
Flow rate = (93,700 kg/day)/(308 kg/cu m)
= 304 cu m/day (56 gpm)
This theoretical value, however, was below the range of 327 to 600 cu
m/day (60 to 110 gpm) observed during the lime mud and clarifier underflow
measurement studies carried out near the end of the campaign. Based on
total calcium, the bulk of which is accounted for by the lime mud and the
filter cake, trial and error calculations fixed the lime mud flow rate at
491 cu m/day (90 gpm).
The data in Table A-2 of the Appendix, relating the clarifier pump
discharge to percent motor load, were used to determine the total flow rate
of the clarifier underflow. The estimated 34 percent motor load corresponds
to a flow rate of 981 cu m/day (180 gpm). A clarifier underflow input of 55
cu m/day (10 gpm) to the filtration process was determined by balancing the
flow equation with the remaining flow of 926 cu m/day (170 gpm) being by-
passed to the lagoon. This split appears consistent with the observed
operation of the control valves.
Tables 8 and 9 summarize the general operations and filtration process
data, respectively, for a typical day's operation. The operations data in
Table 8 are mean calculated values for production and analytical parameters
measured throughout the study period. Table 9 contains adjusted mean values
of analytical data for the samples collected during typical Mud House opera-
tion, that is, for the 22-hour samples collected through January 6, 1977.
The values were adjusted slightly to attain mathematical balances; e.g., the
mean total solids concentration of the clarifier underflow was changed from
102 g/1 to 101 g/1. Omitted from this table are the dissolved COD and the
dissolved calcium balances. In the case of the dissolved COD, it was judged
that the number of analytical values was not sufficient to produce signifi-
cant results. The relatively low concentrations of dissolved calcium,
compared to the total calcium concentrations, did not contribute signifi-
cantly to the balancing process. i
The mass balances conclusively show the preponderance of the lime mud
in the input to the vacuum filtration system. The lime mud to clarifier
underflow ratios are: 8.9 for flow; 58.5 for total solids; 34.5 for volatile
solids; 17.9 for total COD; and 506 for total calcium. The filtration
process was effective in removing 98 percent of the total solids, 88 percent
of the volatile solids, 83 percent of the total COD, and practically all of
44
-------
TABLE 8. GENERAL DATA OF A TYPICAL DAY'S OPERATION
Beets processed: 3,500 metric tons/day
CaO produced: 91 metric tons/day
Ambient air temperature range: low -18°C; high -7°C
Mud House ambient air temperature: 15°C
Clarifier pump load setting: 34 percent
Clarifier underflow pumping rate: 981 cu m/day
Total solids out of the clarifier: 98 kkg/day
Dirt tare as percentage of beet weight: 3.3%
Bulk
pH Temp. Solids Density Viscosity
°C % abs. cp
Clarifier
Underflow
Lime Mud
Filtrate
Filter Cake
9.6 - 10.3 12
49
8.8 - 9.4 27
__
9.6
47.9
—
56.1
1.04
1.40
—
1.50
40
1,210
—
27,000
45
-------
TABLE 9. FILTRATION PROCESS DATA - TYPICAL DAY'S OPERATION
Total Solids
Clarifier
Underflow
Lime Mud
Total Input
Filtrate
Filter Cake
Total Output
Flow
cu m/day
55
491
546
164
382
546
Cone.
g/1
101
667
—
37.7
856
—
Mass
kkg/day
6.0
327
333
6
327
333
Volatile Solids
Cone.
8/1
22.0
84.3
—
33.0
98.9
—
Mass
kkg/day
1.2
41.4
42.6
5.4
37.8
43.2
Total COD
Cone.
S/l
38.0
76.4
—
40.7
86.3
--
Mass
kkg/day
2.1
37.5
39.6
6.7
33.0
39.7
Total Ca
Cone.
8/1
3.0
206
~
1.7
265
—
Mass
kkg/day
0.2
101.1
101.3
0.3
101.1
101.4
-------
the total calcium.
Special Monitoring Period
During the last five days of the campaign, a special program was insti-
tuted to monitor closely the operation of the Mud House during exemplary
operating conditions. This program took place from January 7, 1977, to the
end of the data-collecting period, January 13, 1977. The daily program
included collection of samples and close observation of the operations
during the first shift. The data are presented above, with the mean of the
5-day data points identified as the 8-hour samples.
Table 10 shows a mass balance of the vacuum filtration process for this
special 5-day operating period. To construct the mass balance, the flows
had to be adjusted to correspond to the altered analytical results. The
assumed flow rate of the lime mud was kept at its previous value. Trial and
error calculations were made using the mean concentrations for the period
until a close balance was achieved and the flow rates for the other three
streams were fixed. The clarifier underflow doubled to 109 cu m/day, the
filtrate increased from 164 cu m/day to 210 cu m/day, and the filter cake
was essentially unchanged, from 382 cu m/day to 390 cu m/day.
After the flow rates were fixed, the concentrations were adjusted to
effect a mathematical mass balance, e.g., the total solids concentration of
the clarifier underflow changed from 8.6 to 8.5 g/1, while the total calcium
concentration was unchanged.
The mass balance for this special monitoring period shows that the
filtration process did not change significantly compared to the typical
operation previously discussed and presented in Table 9. The values in
Table 10 indicate that although higher clarifier underflow total solids,
volatile solids, and total COD were processed, the increases were quite
modest and were offset by the reduction in the removal of COD. Total calcium
remained unchanged.
In summary, the dewatering system was not adequately separating the
clarifier underflow solids from the transporting water because clarifier
underflow was being bypassed. Under the best operating conditions, the 8.5
kkg/day of total solids in the clarifier underflow admitted into the filtra-
tion process constitute only nine percent of the 99 kkg/day of total solids
pumped from the clarifier.
ODOR EVALUATION
The results of the odor panel tests are listed in Table 11 and displayed
in Figure 7. The quantities of gas produced by each of the ponds are listed
in Table 12 and graphically displayed in Figure 8.
Odor concentration and gas production for each of the ponds were corre-
lated with several other measured parameters; namely, surface water tempera-
ture, COD, pH, and TDS (Figures 9 and 10). Often there was good positive
correlation between certain parameters in one pond, but no correlation for
47
-------
TABLE 10. FILTRATION PROCESS DATA - SPECIAL FIVE-DAY PERIOD OPERATION
00
Total Solids
Clarifier
Underflow
Lime Mud
Total Input
Filtrate
Filter Cake
Total Output
Flow
cu m/day
109
491
600
210
390
600
Cone.
8/1
78.0
678
~
29.5
859
~
Mass
kkg/day
8.5
333
341.5
6.2
335
341.2
Volatile Solids
Cone.
8/1
19.3
76.8
—
26.7
87.7
--
Mass
kkg/day
2.1
37.7
39.8
5.6
34.2
39.8
Total COD
Cone.
g/1
32.1
53.2
~
31.0
59.2
—
Mass
kkg/day
3.5
26.1
29.6
6.5
23.1
29.6
Total Ca
Cone.
8/1
1.7
218
—
0.9
274
—
Mass
kkg/day
0.2
107
107.2
0.2
107
107.2
-------
TABLE 11. ODOR CONCENTRATION
Date
4-20-77
5-2-77
5-13-77
5-26-77
6-20-77
7-12-77
4-20-77
5-2-77
5-13-77
5-26-77
6-20-77
7-12-77
4-20-77
5-2-77
5-13-77
5-26-77
6-20-77
7-12-77
Q
Odor Cone. , ou/ft
Mud Pond
50
170
960
5.5
600
9
Lime Pond
50
70
1,600
38
12
14
Pond #2
440
1,300
47,000
1,000
270
4.5
Odor Type
Acidic - musty
Stale river
Acidic - Stale river
Acidic Stale river
H_S - Stale river
Stale river
Acidic - musty
Acidic - musty
Acidic - musty
Acidic - musty
H_S - musty
Pig Pen
Pig tail
Pig tail - musty
H2S
H2S
H2S
Musty
49
-------
50i
Ui
o
MUD POND
LIME POND
POND NO,2
0
4/13/77
10 20
30
40 50
TIME, DAYS
70
80 90
7/12/77
Figure 7. Waste Storage ponds - odor vs. -time.
-------
TABLE 12. GAS PRODUCTION
Date Sample
Recorded
4/28/77**
5/6/77
5/12/77
5/19/77
5/26/77
6/2/77
6/9/77
6/16/77
6/23/77
6/30/77
7/7/77
Period of
Sample*
(days)
15#
8+
6
7
7
7
7
7
7
7
7
Gas
Mud Pond
813
65 '
925
1,630
17,250
17,265
1,485
790
7,050
380
195
Production
Lime Pond
589
755
8,185
7,590
350
450
1,860
2,705
2,360
6,700
4,440
ml
Pond #2
1,307
6,918
1,502
11,275
8,336
11,481
12,426
2,736
827
6,578
7,057
* Number of days gas allowed to accumulate
** 4/27/77 for Lime Pond
# 14 days for Lime Pond
+ Four days for Pond 2; nine days for Lime Pond
51
-------
tn
NJ
18—1
16—J
14—
12—
<
O
16-
4—
2-
O
4/13/77
MUD POND
LIME POND
POND NO. 2
r
/ \
v
*
-\
i
^^•""^
,'o
A / / 1
1 % • •
,/v /
/ A / 1
s^-'J^
^•^^^^fc^^^^^^* ^^** ^^^^
i | • |
20 30
\ I
\ \
\ /
\ ^
40 50
TIME, DMS
\
A
Jo '
A ^\
/ V x
Lj\
v\
^ — .
70 80 *
7/7/77
Figure 8. tfasie storage ponds - gas production vs.
-------
50-.
in
OJ
40-
O
x
,0 30'
•-
u.
V.
CO
g20-
o
o
10-
8-1
7-
10
• 6-
O
X
o
3-
30-
25-
2O-
o
•. 15-
o:
10-
5-
0
4/13/77
l
K>
I
20
I r T
30 40
TIME, DAYS
50
60
I
7O
I
80
7/2/77
Figure 9. Odor, COD, «^ -tampewrticHre v&< time - Pond No. 2.
-------
Ui
-P-
12-
0
4/13/77
20
3O 4O
TIME, DAYS
50
60
7*0
e'o
7/7/77
Figure 10. Gas aod TD6 v«. titea ^ Poni. No.- 2.
-------
the same parameters in the other ponds.
Although the pH dropped to 6.8 for a few days in one pond, it generally
remained above 7.3. A positive correlation does exist for all ponds between
odor and pH, and odor and IDS. More odor emanated from the sample sites on
the lime pond than from the mud pond. This might be a case of sample site
selection or it may be due to the fact that the lime pond was much slower in
thawing out and releasing its liquid fraction.
The results of the chemical analyses of the grab samples are shown in
Tables 13 and 14. Sulfide and mercaptan compounds in the samples were
identified by comparing standard mixture peak retention times to the sample
retention times. This method is not absolutely positive for identification
purposes. However, unknown peaks in the sample chromatograms having reten-
tion times identical to those in the standard mixtures have a high confirma-
tion probability.
The Pond No. 2 condensation sample was lost when the sampling tube was
broken. No qualitative or quantitative information was obtained.
Mud pond and lime pond condensation samples indicated methyl sulfide
and n-propyl mercaptan at 35°C, and methyl disulfide at 100°C.
Concentrations of methyl sulfide, n-propyl mercaptan, and methyl disul-
fide were higher in the 100°C sample chromatograms than in the 35°C sample
chromatograms. The concentration increases of these compounds from 35°C to
100°C were not proportional in the mud pond and lime pond samples. The
sample concentration calculations could have introduced some error in these
values.
Comparison of the Teflon bag sample concentrations with the condensate
sample concentrations indicates some significant differences, particularly
in the lime pond samples. A high concentration of methyl disulfide was
found in the 100°C condensate sample, while none was found in the Teflon bag
sample. The phenomenon is suspected to have occurred while transferring air
samples from the field sampling Teflon bags to the laboratory Tedlar bags,
and indicates that transferring air samples should be avoided if at all
possible.
The Pond No. 2 Teflon bag samples had the largest concentrations of
organic sulfides and mercaptans. The lime pond samples had the largest
concentration of hydrogen sulfide. The difficulty lies in translating these
values in terms of odor. A number of variables exist: the odor threshold
of each component, the partial pressure balance, component boiling points,
as well as the unidentified components indicated in the chromatograms.
Total peak area integrator counts for the Teflon bag samples were: lime
pond - 12,800; mud pond - 26,200; and Pond No. 2 - 27,700. This further
indicates that Pond No. 2 had the largest concentration of volatile organic
components.
The carbon adsorption method gave no usable data, with the samples
being identical to the blank.
55
-------
TABLE 13. RESULTS OF CHEMICAL ANALYSIS — MAY 26, 1977 TEFLON BAG SAMPLE
Mud Pond Lime Pond Pond #2
May 26, 1977 Teflon Bag Sample
Nitrogen - % v/v 78.3 77.9 77.9
Hydrogen Sulfide ppm 1 L.T. 1* 3
Methane - % v/v 0.02 L.T. 0.01* 1.35
June 20, 1977 Teflon Bag Sample
Hydrogen Sulfide - ppm
Methane - % v/v
0.03
0.01
0.03
0.02
0.04
0.07
* L.T. = Less than
56
-------
TABLE 14. RESULTS OF CHEMICAL ANALYSIS — JULY 12, 1977 TEFLON BAG SAMPLE
Hydrogen Sulfide (H2S)-ppb*
Methane (CH,)-ppm
Methyl Sulfide ((CH3)2S)-ppb
N-Propyl Mercaptan (C-H7SH)-ppb
o /
Methyl Disulfide ((CH^S^-ppb
Mud Pond
5
1
7
ND
ND
Lime Pond
11
1
2
ND
ND
Pond #2
6
1
10
3
5
ND = Not Detectable
* The calculated H9S values were below the minimum detectable limit of
20 ppb for the test, and the accuracy of the reported values are some-
what questionable. The concentrations reported should be used for com-
parison of sites rather than as true values.
57
-------
ULTIMATE DISPOSAL OF SOLIDS
The farmer whose fields were treated with the filter cake sludge reported
some difficulty in working the ground due to the tendency of the sludge to
compact. He also reported, however, that the two parcels had higher wheat
yields than the rest of the field. MINN-DAK indicated that the pH of the
soil before and after the experiment was not measured, but that the results
were encouraging and that further studies may be carried out under the
auspices of the Red River Valley Association. No problems have resulted
from using filter cake as an embankment and fill material, but this applica-
tion is limited to local demand for this type of material and must stand the
test of time.
58
-------
SECTION 8
DISCUSSION
This section discusses some of the problems encountered in carrying out
the study and summarizes the findings that indicate that the solids handling
and dewatering system was not functioning as intended. The odor study
results are also discussed. The actual operations of the clarifier and
vacuum filter systems are compared to the criteria developed in the ACS
study and those used in design. The section closes with discussion of
changes that could be considered to improve or augment various components of
the total system so that the desired results can be achieved.
DATA COLLECTION
As noted in previous sections, accurate evaluation of the solids
handling system was complicated by many factors. The system lacked adequate
flow control devices and problems were encountered with the flow meters and
stroke counters installed for the study. The filtrate flow meter, after
some initial problems attributed to aeration of the liquid, performed well
most of the time and produced reliable data. The aeration problem was
resolved by moving the meter from the discharge side to the suction side of
the filtrate pumps.
The clarifier underflow flow meter, after producing data for a few
days, operated erratically and eventually stopped functioning. The instru-
ment was returned to the manufacturer for service, but upon reinstallation
at MINN-DAK, it again failed to register flow. It was determined that the
solids carried by this liquid caused the meter to malfunction. The meter
was removed and returned to the manufacturer.
Sludge pump stroke counters were installed to determine the rate of
filter cake production. In reviewing the operating logs, however, it was
determined that the sludge displacement data were subject to wide variations
depending upon how the effective stroke of the pump cylinder was determined.
Different operators used different means to determine what the effective
stroke length was. In some instances, the operators recorded the distance
to be subtracted from the full stroke, while others recorded an estimated
effective stroke.
Difficulties in obtaining actual design information from BMA resulted
in much of the analysis being based on calculated data or values assumed
from observation and measurement of actual operations.
59
-------
The Mud House operators were asked to record the opening of the two
flow control valves to determine the amount of clarifier underflow being
pumped into the mixing tank. It was soon discovered that the operators
manipulated these valves frequently, causing the underflow to flow into the
mixing tank or to be bypassed to the south lagoon in a random fashion.
Several pitfalls were associated with this flow control method, as described
in previous sections. Also, no records were kept of what flows were directed
to each point, and the operators had no standards to maintain, or guidelines
to follow, in deciding whether to filter or to bypass underflow. In general,
it can be said that the day crews tried to take in and filter as much under-
flow as possible and the night shifts preferred to filter straight lime mud.
Another factor that limited underflow filtration was that most routine
maintenance shutdowns were scheduled during the day shift.
RESULTS - DEWATERING SYSTEM
The process flow data support the conclusion that the filter feed
consisted primarily of waste lime mud. The total and volatile solids data
show the close relationship between the lime mud and the filter cake, and
clearly indicate that the amount of clarifier underflow filtered was almost
negligible compared to the amount of lime mud filtered. Lime mud COD values
are generally reflected in both the filtrate and the filter cake and, as
expected, the clarifier underflow did not exert a significant influence on
the filtrate and filter cake COD contents.
The data generally show very low total calcium concentrations in the
clarifier underflow and the filtrate compared to substantially higher concen-
trations in the lime mud and the filter cake. The lime mud contributed most
of the total calcium in the filter cake. The dissolved calcium concentra-
tions are within the same order of magnitude for all four streams. This
conforms to expectations because of the low solubility of calcium salts.
The bulk density and percent solids data, with the exception of the
clarifier underflow, were quite consistent throughout the data collection
period. They also show the negligible contribution of solids from the
clarifier underflow to the filter cake solids.
RESULTS - ODOR STUDY
Analysis of gas samples from the lime pond, mud pond, and one waste-
water pond indicate that methane, hydrogen sulfide, and mercaptans are among
the odorous elements of the off-gases.
Although the carbon adsorption method of gas collection yielded no
usable data, chromatograms indicated that the lime pond had the largest
concentration of hydrogen sulfide and that Pond No. 2 had the largest concen-
trations of organic sulfides and mercaptans. Total peak area integrator
counts also showed that the gases from Pond No. 2 had the highest concentra-
tion of volatile organic components.
During the field sampling, it was observed that a greater concentration
of odors was detected 18 inches beneath the surface in the mud and lime
60
-------
ponds than at 6 or 12 inches. This field observation, and the results of
the chemical analysis showing that different malodorous compounds appear at
different temperatures, illustrate that a variety of compounds is present,
each released at a certain temperature range. Some compounds, through
bacterial action, may appear more than once.
Gas production fluctuated over the 90-day sampling period. Hydrogen
sulfide was released during periods of low pH. This indicates that hydrogen
sulfide can be controlled by maintaining high pH levels.
Possible causes for the formation of other malodorous compounds were
evaluated. The most clearly identifiable changing factor is the addition of
process chemicals that may either cause a sustained lowering of pH or bring
about the development of mercaptans. Table 15 lists process additives that
may be responsible for the generation of various forms of mercaptans.
Further study is required to determine which chemicals are present and
how best to control odor formation.
SYSTEM DESIGN AND PERFORMANCE
The design and operation of the MINN-DAK transport water and solids
dewatering system incorporated some, but not all, of the findings and
recommendations of the ACS study (1). The one major deficiency in the
as-built system is the absence of thickening to attain the desired 20 percent
or higher solids content in the filter feed.
Figure 11 provides a theoretical water balance for the closed loop
water transport system. The primary treatment part of the transport water
system appears to have been designed in conformance with the ACS study.
Table 16 shows design criteria of both the ACS study and those calculated
for the MINN-DAK clarifier. Shown also are actual clarifier performance
data developed during the 1976-77 campaign operation. Certain ACS study
assumptions, e.g., soil tare and underflow solids percent, were used to
calculate the MINN-DAK design criteria.
The single negative element in the MINN-DAK clarifier design appears to
be a shorter detention time. What Table 16 does not show, however, is that
the clarifier recommended in the ACS study is about twice as deep as the
MINN-DAK clarifier. Depth is an important consideration in solids settling,
consolidation, and storage. Because of a lower soil tare, the accual per-
formance of the clarifier exceeded the design criteria, as shown by lower
loadings and higher average underflow solids content and density. However,
as discussed earlier, this flow exhibited a wide variation in both volume
and characteristics as affected by the sludge withdrawal method.
Two other considerations in the design were deficient with respect to
the ACS study recommendations; adequate pH control of the flume water system
and polyelectrolyte addition in the clarifier to promote clarification. The
pH control method presently in use at MINN-DAK, i.e., dumping lime rock in
the beet flume, was not always effective in maintaining the required pH.
MINN-DAK experimented with polyelectrolyte addition to the clarifier under-
flow. This, however, was done in a hit-or-miss manner using mostly old
61
-------
TABLE 15. PROCESS ADDITIVES AND EVENTUAL DISPOSAL
Chemical
Muriatic Acid
Sulfamic Acid
Calcium Hypochlorite
Caustic Soda
Foam Oils
Formaldehyde
Microbiocide
Settling Agent
Soda Ash
Hydrated Lime
Water Treatment Chemicals
Polyphosphate
Disodium Phosphate
Anti-foam
Sodium Sulfite
Lubricants (Grease)
Lubricants (Oils)
Mud Pond
No
No
No
No
Yes
Yes
Yes
No
No
Yes
No
Possibility
Possibility
Lime Pond
No
No
Possibility
No
Yes
Yes
Yes
Yes
No
No
No
Possibility
Possibility
Pond #2
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Slight
Possibility-
Yes
Slight
Possibility
Yes
Possibility
Possibility
I i
62
-------
u>
CLARIFIER
L-!pJ
\
\
i
r
WET
HOPPER
\ /
(33,461*1
UNDERFLOW
PUMP
— v r"
l
(981)
[98]
DEC i a
MUD TARE (121)
[115.6] MAKE-UP
WATER
(860)
LIME ROCK i
(batch dump) |
¥VMOn/
FLUME (33,582) SPRAY
i r
ROCt
(22,942)
• PULP DRYER
ft, (0)[15.6]* (0)
)\i)
( ) —Cu. m/day
[ ] — kkg/day soil solids-dry wt.
* —Estimated
NOTE: Based on 1976-77
campaign averages:
beets—3,502 metric ton/day
tare—3.3%
Figure 11. Water and solids balance for beet transport and clarifier systems.
-------
TABLE 16. CLARIFIER DESIGN AND PERFORMANCE
Element
Beets sliced, kkg/day
Dry soil tare on beets, % wt
Dry flume solids, kkg/day
Flume water flow rate, cu m/day
Clarifier:
Surface area, sq m
Volume, cu m
Dry solids loading,
kg/sq m/day
Hydraulic loading,
cu m/sq m/day
Hydraulic detention time, hr
Underflow dry solids, % wt
Underflow density, g/ml
Underflow flow rate, cu m/day
ACS
Study
3,630
5
182
32,700
965
2,360
188
34
1.9
8
1.02
2,235
MINN-DAK
Design
4,536
5
227
28,800
1,520
1,900
149
19
1.7
8
1.03
2,730
Actual
3,500
3.3
116
34,400
1,520
1,900
76
23
1.3
10
1.04
980
64
-------
polyelectrolytes. The operators were of the opinion that the polyelectrolyte
only added to their operating problems, resulting, in most instances, in
total bypass of the clarifier underflow.
The ACS study (1) indicated that the best filtration results were
obtained when the lime mud was added to the primary clarifier, followed by
secondary thickening and heating of the clarifier underflow. The MINN-DAK
design did not provide for thickening and heating of the clarifier sludge,
although it did include mixing of lime mud and the clarifier underflow in a
mixing tank just before filtration.
The MINN-DAK solids dewatering process, in conformance with ACS study
recommendations, included the use of lime mud as a filtration aid. The
study had determined that the average 2.5-micron particle size of most Red
River Valley soils (Fargo clay) required some form of filter aid and/or
heating to achieve reasonable filtration results. MINN-DAK1s practical
solution was to utilize lime mud as the filter aid. This waste product of
the juice purification process has an average particle size of about 25
microns, an average temperature of about 50°C, and is available in sufficient
quantities (about 10 percent dry solids of the weight of the beets).
The evaluation of filter performance, under the MINN-DAK system opera-
tional conditions, presented some difficulties. Table 17 compares ACS study
results with calculated design and actual performance data for the MINN-DAK
system. In the ACS study, all of the lime mud (quantities not disclosed)
was added to the primary clarifier. The ACS design included secondary
thickening of clarifier underflow, and the filter feed characteristics shown
reflect the results of secondary thickening and heating. The data presented
in this table are consistent with the data presented in Tables 1, 8, 9, and
16.
MINN-DAK operated only one of its two filters to filter essentially all
of the lime mud, which had good filtering characteristics. To filter the
clarifier underflow effectively and maintain the present volumetric loading
of 0.4 cu m/sq m/hr, thickening of the clarifier underflow solids to about
33 percent solids by weight would be required. This flow, when combined
with the waste lime flow, would produce a mixture with a density of 1.26
g/ml and a composition of 16 percent clarifier underflow solids, 24 percent
waste lime solids, and 60 percent water. The required underflow solids
content cannot be achieved in the clarifier as designed under present
operating conditions. It is also doubtful that this could be accomplished
with the very short detention time (12.5 minutes) recommended in the ACS
study for secondary thickening. Thickening studies are required to determine
the optimum loadings and detention time to achieve an adequate solids concen-
tration.
The MINN-DAK design includes pumping of the sludge cake to the storage
lagoon while the ACS study provided for a belt conveyor to carry the filter
cake to a dump truck to be hauled to the disposal site. The ACS study also
called for return of the filtrate to the transport water loop. MINN-DAK
initially returned the filtrate, but discontinued this practice when the
system became overloaded with surplus water. Fresh water input to the
65
-------
TABLE 17. VACUUM FILTRATION PROCESS DESIGN AND PERFORMANCE
Element
Flume solids, kg/hr
Lime mud solids, kg/hr
Filter feed volume, cu m/hr
Filter feed solids, % wt
Filter feed density, g/ml
Filter feed temperature, °C
Filter area, sq m
ACS
Study *
7,580
unk
33
20
1.14
25
126
MINN-DAK
Design
9,500
13,900 13
44**
32**
1.74
18
126
Actual
230
,700
23
45
1.36
45
63
Filter yields:
Dry flume solids,
kg/sq m/hr
Total dry solids,
kg/sq m/hr
Volumetric loading,
cu m/sq m/hr
60
unk
0.3
75
185
.33
216
0.4
* All (quantity unknown) waste lime was added to the primary clarifier.
Filter feed characteristics are the result of secondary thickening
and heating.
** Based on limited data (9)
66
-------
system is required to give the beets a final rinse.
SYSTEM MODIFICATIONS
There are many areas that need improvement and, with modest capital
investment, the system can be improved to provide more efficient operations.
Several changes and additions to the existing transport-water solids treat-
ment facilities are described and illustrated in this section. Figure 12
describes a process flow diagram of the system as it would operate should
these and other proposed changes and additions be implemented. Figure 13
shows proposed modifications to the lagoon system. Figure 2, showing the
Mud House equipment layout without proposed modifications, may be a helpful
reference in visualizing the recommended changes.
pH Control System
Maintenance of a high pH level in the transport water system is required
to inhibit bacterial activity. A pH of 10 or higher is required to prevent
odors, control the growth of bacterial slimes, and enhance the settleability
and filterability of the transport water solids (9, 10). The primary pH
control method used at MINN-DAK, dumping lime rock in the beet flume, was
not always effective in maintaining the required high pH. The installation
of an automatic pH monitor and feed system would be a worthwhile addition to
the present system.
Clarification/Thickening
It has been reported in the literature (10) that a direct relationship
exists between the solids content of the filter feed and the resulting cake.
With its shallow depth and relatively low volume, the existing clarifier did
not provide enough detention time or storage capacity to promote adequate
settling and consolidation of flume solids. Because it was used to thicken
the sludge, a function not included in the design, the clarifier was perhaps
the single most deficient unit process and weakest link in the system as
constructed and operated.
One of the criticisms most often heard from the operating personnel
concerned the sludge removal method employed at the clarifier. The operators
pointed out that with the present sludge suction lift mechanism, more water
was pumped to the Mud House than necessary. This high flow overloaded the
hydraulic capacity of the filters and caused most of the underflow to be
bypassed. When permitted, a high underflow-to-lime mud ratio decreased the
cake solids, caused more frequent filter washings due to blinding, and
increased the possibility of the cake freezing in the discharge pipeline due
to the lower temperature of the mix.
The solids content of the filter feed must be increased to the level
required for adequate filtration results. The ACS study obtained good
filtration results using a high-rate thickener that produced a filter feed
having 20 percent solids with polymer addition and heating to 90°C. Scoville
determined that a filter feed concentration of 20 to 40 percent, obtained by
allowing the clarifier underflow to settle over a 24-hour period at 4°C, was
67
-------
SUPERNATANT
MAKE-UP WATER
TO BEET WASHER
EXISTING
RECEIVERS
VACUUM
PUMP
FILTER CAKE
FLOW METER (TYPICAL)
- ' 1^1 U-"sl
FILTER
c>
s
— «
FILTER
NEW
RECEIVERS
|VACUUM
PUMP
AIR
FILTRATE TO
LIQUID STORAGE
AIR
Figure 12. Proposed process flow schematic.
-------
Drainage ditclL
•Filtrate
Cake storage
Mud House
Proposed Underflow "by-pass
Cake storage
Existing underflow
Proposed underflow
Reserve
Storage
Underflow
Storage
Figure 13. Proposed plan, of 'Bvud house and storage lagoons.
^ Underflow
Storage
)
i
i
j_
j
i
1 i
ZTsJ i
k \
-------
necessary for adequate cake yields (11).
There are two types of thickener that can DC used to achieve the desired
solids content and characteristics of the filter feed; a conventional gravity
thickener relying on the natural settleability of the sludge solids, or a
high-rate thickener that would rely on polyelectrolyte addition and heating
the sludge as done in the ACS study.
Conventional gravity thickeners are designed on the basis of hydraulic
and solids loadings. As a rule, solids loadings govern the design, which
varies with the type of influent solids and application. Solids loadings of
100 to 150 kg/sq m/day (20 to 30 Ib/sq ft/day) are typically used in the
design of units to thicken primary municipal sludge. Units used to thicken
water treatment sludges high in calcium carbonate are designed using solids
loadings of about 200 kg/sq m/day (40 Ib/sq ft/day). Gravity thickeners
usually have minimum depths of 3 meters (10 ft) and detention times of up to
24 hours are typically provided for municipal treatment applications (12).
The use of conventional thickeners in the treatment of beet flume solids has
not been reported in the literature.
The high-rate thickener used in the ACS study had a detention time of
12.5 minutes. The solids loading on this unit was calculated at over 11,000
kg/sq m/day (2,300 Ib/sq ft/day). This loading excludes the solids contrib-
uted by the addition of the lime mud.
An analysis of the as-built system indicates that the most practical
solution at MINN-DAK would probably be to construct thickening and sludge
pumping facilities adjacent to the existing clarifier. The main shortcomings
in the clarifier design, e.g., detention time, sludge storage capacity, and
sludge withdrawal method, can be minimized by designing a thickener for
adequate detention time at a maximum sludge withdrawal rate.
Another factor that must be considered is the point at which the lime
mud is added. The ACS study determined that the best filtration results
were obtained when lime mud was added to the clarifier. If this were done
at MINN-DAK, the lime mud solids would at least double the solids loading on
the clarifier and would add to the solids storage and handling problems
presently experienced there. If a thickener were added, the additional
solids or volume of the lime mud stream should be included in the calcula-
tions of the thickener dimensions because the lime mud would have to be
pumped directly to the thickener. Preliminary indications are that a con-
ventional gravity thickener would have a higher capital cost than the high-
rate thickener, but the former would be more economical to operate. Costs
must be determined through pilot .studies, however.
The operation of the existing clarifier would remain essentially
unchanged. The supernatant would continue to flow to the beet flume and the
sludge would be pumped to the new thickener. New positive displacement
pumps and a new pipeline should be installed to pump the thickener underflow
to the Mud House. Positive displacement pumps are widely used to pump heavy
sludges and industrial slurries. Several pluggings of the existing 10.2 cm
(4-inch) pipeline occurred during the study and past campaigns. A new
70
-------
larger diameter pipeline might minimize interruptions due to plugging. The
existing pipeline would be retained for use during maintenance to keep the
new pipeline free of obstructions. Heat-tracing and insulating the pipeline
would raise the temperature and reduce the viscosity of the sludge, making
it more fluid before pumping.
A small local control room should be provided at the new pump station,
with alternate control provided remotely from the Mud House. A Parshall
flume or similar type of flow meter would be required to record the flow of
the clarifier supernatant to the beet flume. Flow meters of appropriate
types should be installed on the following process flows: clarifier under-
flow to the thickener; waste lime flow to the thickener; thickener superna-
tant to the clarifier; and thickener underflow to the Mud House. Equipment
alarms, a sludge density meter, and a thickener sludge-bed depth monitor
should also be installed. Additional flow control and monitoring require-
ments are discussed in the proposed modifications to the Mud House equipment.
The type of thickener used in the new system would determine the operating
requirements at this remote location. A telephone should be installed to
maintain communications between the Mud House and the clarifier/thickener
facility.
Mud House
The Mud House personnel attempted to operate both filters simultane-
ously on several occasions. After a few hours, however, it became necessary
to revert to the standard plant procedure of operating a single filter.
Several design deficiencies were responsible for this situation: the
excessive volume of diluted clarifier underflow admitted; the common vacuum
and filtrate extraction system; and the inability of the sludge pumps to
handle the sludge quantities produced by the two filters. The problem of
excessive amounts of dilute clarifier underflow has been addressed previously.
With respect to the common vacuum and filtrate extraction system,
Figure 2 shows the two receivers connected in series while the filters and
the vacuum pumps had parallel arrangements. The filters, each having cloths
of different age, state of repair, or degree of cleanliness, responded
differently to the common vacuum application, resulting in unequal cake
production rates and qualities. Although there were duplicate vacuum pumps,
receiver tanks, and filters, it was not possible to operate the two filters
because of the present piping arrangement and the behavior of the filters.
This resulted in one of the filters being shut down.
Pumps and similar equipment are normally designed as redundant units
for standby service. It is difficult, however, to justify the installation
of a filter of the size and cost of those used at the Mud House for redun-
dancy. These filters were designed to work concurrently during peak sludge
production. They could be operated simultaneously by adding a few linear
feet of pipe, a few strategically located control valves, two additional
receivers and, if required, some back-up equipment. It is unlikely that the
filtrate pumps need replacement or that a third vacuum pump would be required
for standby service. These expenditures would, in any case, be very modest
when compared to the sizable capital .investment already made in the
71
-------
dewatering facility.
Two filters operating simultaneously would overtax the capacity of the
sludge pumps. These pumps, although rugged and reliable, have been the
subject of constant attention and maintenance. The practice of trickling
water onto the filter cake to condition it for pumping defeats the dewatering
process. Also, the extreme North Dakota winters make pumping a heavy sludge
through an exposed pipeline a very risky proposition. For these reasons,
the pump and pipeline method of transporting the filter cake from the Mud
House to the lagoons should be abandoned and in its place a solids-handling
system, such as a conveyor, should be designed and installed.
The operation of the Mud House can be upgraded by installing instru-
ments to control and monitor process flows, developing procedures for
recording daily operating data, and clearly defining the operators' respon-
sibilities. An accounting must be made of all process influent and effluent
flows. To do this, flow meters should be installed on the filtrate, the new
thickener underflow, and the underflow bypass pipelines. A scale to monitor
the production of filter cake could also be installed in conjunction with
the proposed conveyor system. However, if all other process flows are
adequately accounted for, this last item may be redundant. The volume of
sludge accumulated in the lagoons on a weekly, bi-weekly, or monthly basis
could be monitored as an alternative to the scale.
An adequately sized, furnished, and isolated control room should be
provided. This control room should be conveniently located within the Mud
House and should house a central control panel showing all process flows and
other equipment monitors required for the operation of the entire system.
Sludge Lagoons
The two-lagoon system should be modified for consistency with some of
the process design changes recommended above. The underflow bypass should
be piped to the farthest cells in the new layout to minimize the distance
that the dewatered cake must be conveyed. The dewatered cake should be
stored, with respect to the Mud House, in the nearest half of the south
lagoon and the nearest two-thirds of the north lagoon. The most distant
third of the north lagoon should be held in reserve for either underflow or
cake storage. The dikes for this new system can be constructed using the
dried sludge cake from previous campaigns. Methods -for collecting and
removing free water should be developed to avoid odor nuisance due to anaero-
bic conditions.
ULTIMATE DISPOSAL OF SOLIDS ,
As far as reclaiming the clarifier underflow solids, MINN-DAK indicated
that the management is confident of its ability to demonstrate to the growers
that this sludge is suitable for soil cultivation purposes. Because of the
obvious economic impact of transporting sludge, the water content of the
sludge becomes a very important factor in the management of this material.
72
-------
Collection of information from local growers about ultimate disposal
practices or possibilities and their technical and economic implications was
outside the scope of this study. Additional research is needed to evaluate
the alternatives available for ultimate disposal.
73
-------
REFERENCES
1. Environmental Protection Technology Series, Separation, Dewatering, and
Disposal of Sugar Beet Transport Water Solids, USEPA, EPA-660/2-74-093,
December, 1974.
2. "Some Facts You Might Want to Know About MINN-DAK," an informational
brochure issued by MINN-DAK.
3. Gordon Rudolph, "AC-REPORTS," Reporter, Volume 2 - November 12, August,
1976.
4. Minnesota Pollution Control Regulation, APC 9, July 7, 1969: amended
September 14, 1971.
5. ASTM D1391-57
6. Benforado, D. M., et al., "Development of an Odor Panel for Evaluation
of Odor Control Equipment," Journal APCA 19 (2): 101-105.
7. ASTM D1605-60
8. ASTM D1354-60
9. Development Document for Effluent Limitations Guidelines and New Source
Performance Standards for the Beet Sugar Processing Industry, USEPA,
April 6, 1973.
10. Process Design Manual for Upgrading Existing Wastewater Treatment
Plants, USEPA, October, 1974. Sludge thickening, stabilization, and
dewatering.
11. Vacuum Filtration of Beet Sugar Processing Wastes, thesis, NDSU, W. L.
Scoville, September, 1974.
12. Process Design Manual for Sludge Treatment and Disposal, USEPA, October,
1974.
74
-------
BIBLIOGRAPHY
Facts about Sugarbeets and Beet Sugar in the Upper Midwest,
American Crystal Sugar Company.
Fischer, James H., "Biological Treatment of Concentrated Sugar
Beet Wastes," EPA-660/2-74-028, Washington, B.C., June, 1974.
Oswald, Wm. J., et al., "Anaerobic-Aerobic Ponds for Beet Sugar
Waste Treatment," EPA-R2-73-025, Washington, B.C., February, 1973.
Standard Methods for the Examination of Water and Wastewater,
14th edition 19, APHA, AWWA, WPCF.
75
-------
APPENDIX A
ADDITIONAL DATA TABLES
TABLE A-l. FILTRATE FLOW RATE DATA
Date
12/13/76
12/14/76
12/16/76
12/17/76
12/19/76
12/29/76
12/30/76
12/31/76
01/02/77
01/03/77
01/04/77
01/05/77
01/06/77
01/07/77
01/07/77
01/08/77
01/09/77
01/10/77
01/11/77
01/12/77
01/13/77
Flow Rate
liters/min.
85.2
90.5
98.0
101.1
135.5
186.6
115.8
103.3
136.3
74.2
102.2
138.9
83.3
90.5
133.6
59.8
98.0
88.9
179.0
128.7
78.0
Operating
hours
14
10
8
18
12
13
16
22
24
8
8
10
6
4
12
16
14
5
22
7
8
Composite
liters/min. -hours
1,193
905
784
1,820
1,626
2,426
1,853
2,273
3,271
594
818
1,389
500
362
1,603
957
1,372
444
3,938
901
624
Totals
Weighted Avg.
257
29,653
115.4
76
-------
TABLE A-2. CLARIFIES UNDERFLOW TO VACUUM FILTERS
Clarifier Pump
East
Valve
Opening*
cm
6.4
5.7
5.1
4.4
3.8
3.2
2.5 (1 in)
1.9
1.3
Closed
30%
1/min
0
0
0
0
0
95
210
360
510
530
% Total
0
0
0
0
0
20
40
70
95
100
Motor Discharge vs % Load
32%
1/min
0
0
0
95
230
380
455
530
570
605
% Total
0
0
0
15
40
60
75
90
95
100
34%
1/min
0
0
75
190
300
395
492
585
645
680
% Total
0
0
10
25
45
60
70
85
95
100
36%
1/min
0
0
115
225
340
455
550
645
700
755
% Total
0
0
15
30
45
60
70
85
95
100
For location, see Figure 2.
77
-------
Time
TABLE A-3. INSTANTANEOUS pH AND VISCOSITY DATA
Instantaneous pH (12-14-76)
Clarifier Underflow
Filtrate
7:30 p.m.
8:30 p.m.
9:30 p.m.
10:30 p.m.
11:30 p.m.
10.0
9.6
10.3
10.1
10.0
8.8
9.0
9.4
9.4
8.9
Average
Viscosity
Date
12/22/76
12/22/76
12/28/76
01/06/77
01/10/77
01/14/77
01/17/77
01/18/77
Clarifier
Underflow
Vise.
cps
_
-
20
15
35
60
50
45
Temp.
°C
_
-
22
25
25
23
24
25
Waste Lime
Vise.
cps
1,480
1,320
1,100
660
740
720
1,900
1,750
Temp.
°C
26
25
23
25
25
26
25
24
Filter
Vise .
cps
_
-
24,000
24,000
12,000
46,000
31,000
24,000
Cake
Temp.
°C
_
-
22
24
25
23
23
23
40
1,210
27,000
78
-------
TABLE A-4. SUPPLEMENTARY DATA
Date
11/09/76
11/10/76
11/11/76
11/12/76
11/13/76
11/14/76
11/15/76
11/16/76
11/17/76
11/18/76
11/19/76
11/20/76
11/21/76
11/22/76
11/23/76
11/24/76
11/25/76
11/26/76
11/27/76
11/28/76
11/29/76
11/30/76
12/01/76
12/02/76
12/03/76
12/04/76
12/05/76
12/06/76
12/07/76
12/08/76
12/09/76
12/10/76
12/11/76
12/12/76
12/13/76
12/14/76
12/15/76
12/16/76
12/17/76
12/18/76
12/19/76
12/20/76
12/21/76
12/22/76
12/23/76
12/24/76
12/25/76
12/26/76
12/27/76
12/28/76
12/29/76
12/30/76
12/31/76
01/01/77
01/02/77
01/03/77
01/04/77
01/05/77
01/06/77
01/07/77
01/08/77
01/09/77
01/10/77
01/11/77
01/12/77
01/13/77
Average
Total
Beets Processed
Metric Tons
3,822
3,765
3,443
3,711
3,729
3,725
3,274
3,342
3,261
3,312
3,728
3,418
3,652
3,416
3,405
2,898
2,442
2,732
3,455
3,668
3,565
3,634
3,618
3,664
3,160
3,705
3,282
3,543
3,198
3,432
3,795
3,669
3,652
3,846
3,402
3.518
3,524
3,549
3,622
3,200
3,654
3,526
3,283
3,533
2,915
3,471
3,748
3,584
3,351
3,431
3,554
3,073
3,634
3,539
3,676
3,657
3,815
3,378
3,233
3,497
3,550
3,402
2,467
3,477
3,318
3,258
3,452
227,800
- i i
CaO Consumed
Metric Tons
98
100
76
89
94
93
93
100
93
85
98
83
93
91
89
72
65
64
92
90
81
93
88
87
84
93
93
93
90
92
95
93
91
94
82
89
94
92
87
87
102
87
90
102
84
98
103
97
99
99
100
90
99
92
93
87
92
83
91
83
85
89
64
89
86
81
91
~
Clarifier Pump
I Motor Load
33.3
34.7
36.4
36.9
35.5
36.8
32.3
33.8
32.0
39.1
31.4
37.5
34.7
35.0
34.8
35.8
35.5
32.8
35.8
33.5
34.8
33.1
34.6
34.9
35.4
35.5
34.4
34.9
35.0
32.4
33.7
34.3
36.2
35.1
33.4
31.7
34.4
34.5
34.6
34.6
33.0
34.0
35.5
34.4
32.0
32.3
32.6
32.0
31.6
31.9
33.0
32.6
38.2
39.6
40.0
32.4
30.7
32.7
35.5
30.2
32.2
31.9
33.9
33.8
32.1
30.7
33.6
--
Anbient
High
9
-2
-6
-5
2
A
4
7
8
12
5
3
1
-3
-4
4
3
1
-11
-13
-14
-9
-9
-12
-8
-3
-8
-21
-16
-14
-8
-9
2
-9
-3
4
2
7
3
4
1
-12
-5
1
-8
-2
-4
-4
3
-15
-18
-25
-22
-13
-11
-18
-14
-13
-13
-16
-17
-23
-27
-22
-18
-13
-7
—
Temp. I
Low
-3
-7
-14
-10
-13
-16
-13
-13
-6
-6
-6
-10
-4
-11
-9
-7
-3
-12
-22
-24
-19
-2t
-18
-26
-17
-13
-19
-26
-24
-25
-15
-24
-22
-18
-18
-7
-7
-7
-6
-7
-13
-22
-21
-12
-22
-15
-13
-19
-17
-22
-28
-33
-28
-29
-25
-26
-22
-20
-18
-24
-31
-37
-31
-28
-36
-21
-18
--
79
-------
TABLE A-5. MINN-DAK'S 1976-1977 CAMPAIGN WASTEWATER INVENTORY
Extracted from beets
Factory processes (condenser,
clean-up, etc.)
Transport water system
Filtrate
Clarifier underflow lagoon**
Filter cake lagoon//
Mud House, runoff, etc.##
Quantity
(cu m)
45,420
174,110
19,188
43,290
2,691
10,062
Flow Rate*
(cu m/day)
388
1,488
164
370
23
86
Totals
294,761
2,519
* Average spread over a 117-day campaign.
** Assumes 40 percent of clarifier underflow lagoon contents becomes
free water. The average flow rate bypassed was 926 cu m/day.
# Assumes 6 percent of the filter cake volume becomes free water. The
average filter cake solids was 382 cu m/day before dilution water was
added for pumping.
## Includes filter wash and Mud House clean-up water.
80
-------
APPENDIX B
MUD HOUSE LOG SUMMARY
In the following day-to-day report on the Mud House activities,
the initial paragraph will summarize sample collection information and any
highlights of special events taking place on that day. Sampling periods are
designated from 1 through 12, with sampling period No. 1 corresponding to
the 9 a.m. collecting period. Missing sampling periods will be identified
and will be followed by reasons, if any, entered in the log. The second
paragraph will summarize any flow data, actual or estimated from log entries,
and the third paragraph will summarize data on the filters' operation. The
interpreter of this log will, from time to time, offer his comments in
parentheses or a fourth paragraph at the end of the day.
This format will be abandoned starting with the January 7, 1977,
entry when data will be entered following the chronological order of events.
11/9/76 Began monitoring and sample collection at the Mud House. The
south filter was down indefinitely waiting for parts ordered from
Germany to rebuild the air blow-off unit that blew up when an
operator attempted to run the filter with too much air in it.
Full sampling at all stations.
No data were entered on clarifier underflow distribution.
The north filter operated at 3 min, 42 sec per revolution, sub-
mergence between full and half-full, and vacuum of 8 to 12 inches
Hg-
11/10/76 Samples 1, 3, and 4 were not taken: polymer tests conducted by
MINN-DAK.
No data were entered on clarifier underflow distribution.
The north filter operated at 3 min, 42 sec per revolution, sub-
mergence between 3 and 16 inches from the top, and vacuum of 4.5
to 10.5 inches Hg.
11/12/76 Samples 5 through 12 were not taken: the Mud House was shut down
because of a broken binding wire on the north filter.
No data were entered on clarifier underflow distribution.
81
-------
The north filter operated, from 8 a.m. to 4 p.m., at 3 min and 42
sec per revolution, submergence between full and one-third full,
and vacuum of 5 to 10 inches Hg.
11/14/76 Full sampling at all stations.
No data were entered on clarifier underflow distribution.
The north filter operated at 3 min, 42 sec per revolution, sub-
mergence between full to 3.5 inches from the top, and vacuum of 3
to 9 inches Hg.
11/15/76 Sample No. 8 was not taken but no reason was given.
Inconclusive data on clarifier underflow distribution were entered.
The north filter operated at 3 min, 42 sec per revolution until
4:00 p.m. at which time the speed changed to 2 min, 30 sec per
revolution, submergence between full and 8.5 inches from the top,
and vacuum of 5 to 11 inches Hg.
11/16/76 Sample No. 2 was not taken: the filter was shut down to wash the
drum. A high filtrate temperature of 32°C and a low vacuum of 6
inches Hg, at 3:00 a.m., was reported as the result of "cutting,"
mostly waste lime.
Inconclusive data on clarifier underflow distribution were entered.
The north filter operated at 2 min, 30 sec per revolution, submer-
gence between full and 21 inches from the top, and vacuum of 5 to
11 inches Hg.
11/17/76 New log sheets were put into effect. Samples No. 4 and 5 were not
taken: the filter was shut down to repair the agitator bearing;
then the plant was shut down for lack of waste lime; tried to
filter underflow only but the filter clogged and had to be washed.
The third shift reported unable to take much underflow into the
mixing tank because of the high pumping rate required to lower the
clarifier mud level (this made the underflow too thin).
The first shift reported 75 percent underflow bypass; the second
shift's entries were inconclusive; the third shift reported about
55 percent bypass. (These estimates were questionable; only total
bypass entries are considered reliable.)
I i
The north filter operated, except as noted above, at 2 min, 30 seel
per revolution, submergence mostly full to half-full, and vacuum
of 8 to 12 inches Hg.
11/18/76 Samples No. 5 and 11 were not taken: shut down the filter to wash
the cloth and to reset the cutting blade; shut down the filter at
5:00 a.m. to repair binding wire and to wash the cloth.
82
-------
The underflow flow meter was installed and started at 11:00 a.m.;
the calculated flow rate was 57 gpm for 21 hours of operation.
Percentages of underflow bypassed were reported as follows: 75 by
the first and second shifts and 80 by the third shift.
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between full and 18 inches from the
top, and vacuum of 8 to 11.5 inches Hg.
11/19/76 Full sampling at all stations.
The underflow flow rate was calculated at 105 gpm for 22 hrs of
operation. The reported bypassed percentages were: 80 by the
first shift; 75 by the second shift; and 80 by the third shift.
The north filter operated continuously at 2 min, 30 sec per
revolution, submergence from 48 inches below the top for the first
8 hours to mostly full for the balance, and vacuum of 4 to 11
inches Hg.
Comment: A trouble-free and smooth running working day attributed
to filtering mostly waste lime.
11/21/76 Samples No. 4 and 11 were not taken: shut down the filter to
repair agitator; shut down again at 5:00 a.m. for unspecified
repairs.
The underflow flow rate was calculated at 57 gpm for 22 hrs of
operation. Bypassed percentages were reported as follows: 70 by
the first and second shifts; 65 by the third shift.
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between full and 21 inches from the
top, and vacuum of 5 to 10 inches Hg.
Comment: The filtrate temperature dips following both shutdowns
as the liquid in the filter pan cools off without fresh input of
hot waste lime.
11/22/76 Sample No. 1 was not taken: the filter was shut down for washing.
The underflow flow meter yielded a calculated flow rate of 58 gpm
for 20 hrs of operation. Bypassed underflow percentages were
reported as follows: after an initial 3-hr total bypass, only 10
percent was bypassed during periods 2 through 6 (this shows in the
low filtrate temperature of 20°C but it is doubtful that the
amount filtered is as high as the estimate indicates); 60 percent
was bypassed for the balance (this includes a zero bypass 2-hour
period).
83
-------
The north filter operated continuously from 11:00 a.m., at 2 rain,
30 sec per revolution, submergence from full to three quarters
full, and vacuum of 5 to 11.5 inches Hg.
11/23/76 Samples 1, 7, and 8 were not taken: shut down the filter to wash
the cloth during period 1; no explanation was given for shutdown
during periods 7 and 8. Began monitoring the temperature of the
waste lime at the factory.
The underflow meter stopped recording flow and went into steady
fault condition. Bypassed underflow percentages were reported as
follows: 50 by the first shift; 75 by the second shift; 25 by the
third shift (no underflow appears to have been taken, however, as
evidenced by the high filtrate temperature).
The north filter operated at 2 rain and 30 sec per revolution,
submergence between full and 28 inches from the top, and vacuum of
5 to 11 inches Hg.
Comment: Estimates of the percent of underflow bypassed vary from
operator to operator. Actual amounts of underflow being filtered
are suspected to be only a fraction of the reported estimates.
11/24/76 Full sampling at all stations, although the plant was shut down
between sampling hours to wash the filter, patch the cloth, and
switch the sludge pumps.
The underflow flow meter was out of service. Bypassed underflow
percentages were reported as follows: 40 by the first shift; 75
by the second shift; and 60 by the third shift.
The north filter operated at 2 min and 30 sec per revolution,
submergence between full and 12 inches from the top, and vacuum of
4 to 11.5 inches Hg.
11/25/76 Sample No. 2 was not taken: shut down the filter to wash the
cloth. The second and third shifts reported that little waste
lime was being delivered from the factory.
The underflow flow meter remains out of service. Bypassed under-
flow percentages were reported as follows: 35 by the first shift;
and 90 by the second and third shifts (including 8 hrs. of total
bypass).
The north filter operated at 2 min and 30 sec per revolution,
submergence between full and 30 inches from the top, and vacuum of
2 to 11 inches Hg.
11/26/76 Sample No. 2 was not taken: the underflow line plugged at 8:10
a.m.; the line was cleared by 9:40 a.m. but, because of large
amounts of sand in the clarifier, the filter was shut down for
washing.
84
-------
No data on the underflow flow meter were entered. Bypassed under-
flow percentages were reported as follows: 50 by the first shift;
40 by the second shift, which included a zero bypass period; 50 by
the third shift.
The north filter operated, as noted above, at 2 rain and 30 sec per
revolution, submergence between full and 12 inches from the top,
and vacuum of 4 to 11 inches Hg.
11/28/76 No samples were collected during the first and second shift, but
no reasons were given.
The third shift reported bypassing 60 percent of the underflow.
The north filter operated, except as noted above, at an unknown
speed, submergence kept at half-full to repair bearing seal on
rim, and vacuum of 6 to 8 inches Hg.
11/29/76 Several samples were not taken as follows: Period l--no reason
given; Period 4--repaired a broken valve on the sludge pump;
Periods 6 through 9—the clarifier was shut down to replace the
casing on the clarifier pump.
The clarifier was shut down during most of the first and second
shifts; the third shift reported 60 percent bypass (total bypass
is suspected as clarifier temperature remained unchanged).
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence full to half-full, and vacuum of 3 to
9 inches Hg.
11/30/76 Underflow samples 4 through 9 were not taken: the underflow line
plugged. The plant continued operating, filtering waste lime
except for washing of the drum and patching of the cloth during
period No. 9.
The underflow meter was returned to the manufacturer. When flow
from the clarifier was restored, the third shift reported 40
percent bypass for 6 hrs.
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between three-quarters and half-full
due to leaks around main bearings, and vacuum of 5.5 to 8.5 inches
Hg.
Comment: Today's filter cake and filtrate samples had virtually
no underflow contribution.
12/1/76 Underflow samples No. 3, 6, 9, and 10 were not taken: the clari-
fier underflow line plugged but filtration was continued. The
filter was shut down to wash the drum during period No. 6.
85
-------
Bypassed underflow percentages, when available, were reported as
follows: 50 by the first shift, 75 by the second shift, and 100
by the third shift.
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between 5 and 18 inches from the top,
and vacuum of 5 to 10 inches Hg.
12/2/76 Samples 3, 4, and 10 were not taken: the filter was shut down to
clean the filter cloth and patch the drum cover.
Bypassed underflow percentages were reported as follows: 90 by
the first shift; 20 by the second shift (this was corrected:
initial entries indicate 80 instead of 20; this operator may have
estimated the fraction "in" rather than "out"); 45 by the third
shift (75 using same argument indicated above).
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between 3 and 18 inches from the top,
and vacuum of 5 to 9.5 inches Hg.
12/3/76 Full sampling at all stations throughout the day.
The average underflow bypass was reported at 30 percent for the
day (all shifts appear very even).
The north filter operated at 2 min, 30 sec per revolution, sub-
mergence from full to half-full, and vacuum of 5 to 8 inches Hg.
12/5/76 No samples were taken during the second shift, although no reasons
were given.
Bypassed underflow percentages were reported as follows: 25 by
the first shift (for two periods only; the other two are illegible
obliterated); and about 25 by the third shift.
The north filter operated at 2 min, 30 sec per revolution, submerg
ence from full to two-thirds full, and vacuum of 4 to 8 inches Hg.
12/6/76 Six samples were not taken as follows: 2 and 3 to repair the
polymer pump; 6 through 9 to rewire the polymer pump. (The filter
was shut down 12 hrs.)
Bypassed underflow percentages were reported as follows: 30 by
the first and second shifts; 45 by the third shift. '
/
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between full and 7 inches from the
top, and vacuum of 2 to 9 inches Hg.
12/7/76 The clarifier underflow line was reported plugged at 9:00 a.m. but
there was full sampling at all stations.
86
-------
Bypassed underflow was reported at 25 percent throughout the day.
The north filter operated at 2 min, 30 sec, at full submergence
except during the first and the last two periods when it ran
half-full because of a leak in the west side packing, and vacuum
of 3 to 8.5 inches Kg.
12/8/76 Sample No. 3 was not taken: the Mud House was shut down to wash
the drums.
Bypassed underflow percentages were reported as follows: 45 by
the first shift; 35 by the second shift; and 30 by the third
shift. (These estimates appear very conservative.)
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, at near full submergence except for three periods,
and vacuum of 4 to 9 inches Hg.
12/9/76 Sample No. 1 was not taken: the filter was shut down to clean the
drum.
Except for the initial total bypass period, the reported underflow
bypass was held steady at 25 percent throughout the day.
The north filter operated, except as noted above, at 2 min, 30
sec, submergence full to half-full, and vacuum of 3 to 9 inches
Hg.
12/10/76 Sample No. 11 was not taken: the filter was shut down to wash the
drum.
Bypassed underflow percentages were reported as follows: 25 by
the first and second shifts; and 50 by the third shift.
The north filter operated, except as noted above, at 2 min, 30
sec, submergence between full and half-full, vacuum of 2 to 10
inches Hg.
12/12/76 Sample No. 2 was not taken: the filter was shut down to clean the
drum.
Bypassed underflow percentages were reported as follows: 60 by
the first shift; 25 by the second and third shifts. (Very high
filtrate temperatures, 29°C to 36°C, contradict these estimates.)
The north filter operated except as noted above, at 2 min, 30 sec,
at mostly full submergence except for one half-full period and
vacuum of 4 to 8.5 inches Hg.
12/13/76 Samples No. 9 and 10 were not taken, but no reason was given.
87
-------
12/14/76
12/15/76
12/16/77
The filtrate meter was installed and started at 11:00 a.m. The
filtrate flow rate was calculated at 22.5 gpm for a 14-hour
operating period. Bypassed underflow percentages were reported as
follows: 20 by the first and second shifts; near zero by the
third shift (a high filtrate temperature, 33°C, contradicts the
third shift's estimate).
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence full to half-full, and vacuum of 2 to
8 inches Hg.
Samples No. 2 and 6 were not taken: first the Mud House was shut
down to wash the drum, switch mud pumps, and patch holes in the
cloth; shut down a second time to clean the drum. Stroke counters
were installed on the sludge pumps.
The filtrate flow rate was calculated at 23.9 gpm for 10 selected
hours of operation.
Bypassed underflow percentages were reported as follows: 55 by
the first shift; 65 by the second shift; and 40 by the third
shift.
The north filter operated, except as noted above, at 2 min, 30 sec
per revolution, submergence between full and half-full, and vacuum
of 4 to 8.5 inches Hg.
The first six samples were not taken: the Mud House was shut down
because of a broken binding wire on the north filter drum. The
south filter was started for the first time. The sludge pump was
repaired during the shutdown.
The filtrate flow rate was calculated at 8 gpm (no good; too low).
A 25 percent underflow bypass was reported for the remainder of
the day.
The south filter operated from 9:00 p.m. at 2 min, 41 sec per
revolution, submergence full to half-full, and vacuum of 4 to 9
inches Hg.
New log sheets were started. Sample No. 6 was not taken:
House was shut down to clean the drum.
the Mud
The filtrate flow meter went into fault and empty conditions
during the first two periods and was adjusted; the flow rate was
calculated at 25.9 gpm for 8 hrs of operation; the meter went into
fault condition again during the last period. Underflow was taken
in for about 3 hours during the first shift and for about 2 hours
during the second and third shifts, as determined by the lagoon
bypass valve log put into effect today.
88
-------
The south filter operated, except as noted above, at 2 min, 41 sec
per revolution, submergence full to 6 inches from the top, and
vacuum of 5 to 11.5 inches Hg. (The filter speed will no longer
be recorded in the log because this speed is maintained throughout
the campaign; only changes in this speed will be recorded in the
log.)
Comment. A log to record valve stem length was initiated on this
day. Without knowledge of the instantaneous rate of flow, however,
the actual distribution cannot be estimated. The criteria for
determining the estimated time (not flow rate) during which under-
flow was taken inside is an east valve opening of 2 inches or
less.
12/17/76 Sample No. 1 was not taken: the filter was shut down to clean the
drum. Sludge was sent outside for 5 minutes at 10:25 a.m. to fix
an oil leak in the pump.
The level in the filtrate-air receiver was adjusted to keep air
out of the filtrate line which has been causing the filtrate flow
meter to go into fault; the filtrate flow rate was calculated at
26.3 gpm for 22 hours of operation. Underflow was taken in for
about 2 hours during the first shift, and for about 1 hour each
during the second and third shifts.
The south filter operated, except as noted above, at submergence
between 2 and 12 inches from the top, and vacuum of 6 to 11.5
inches Hg.
12/18/76 Today was not a scheduled sampling day. Underflow was taken in
for about 1 hour each during the first and second shifts;
apparently none was taken in during the third shift. The third
shift helper did not show up. Problems with gravel from the
clarifier were reported as of yesterday.
12/19/76 Full sampling at all stations. Soap, from washing oil off the
filter cloth, caused the filtrate to foam, entrapping air and
making the flow meter go into fault. A new cloth was put on the
north filter drum. The sludge pump counter could not be read.
The filtrate flow rate was calculated at 35.8 gpm for 12 hours of
operation. Underflow was taken in for about one-half hour during
the first shift, and for about three hours during the second
shift; no information was recorded by the third shift.
The south filter operated at submergence between full and half-
full, and vacuum of 4 to 9 inches Hg.
12/20/76 Samples No. 2, 3, and 7 were not taken; the filter was shut down
to wash and change the drums, and to fix the sludge pump; the
plant was shut down again to switch the drums. The west sludge
pump was repacked; the east sludge pump has a cracked hydraulic
cylinder.
89
-------
12/21/76
Underflow was taken in for about 4 hours each during the first and
second shifts; the third shift again failed to record valve settings.
The filtrate flow meter went into a steady fault condition. (No
reliable data were produced.)
The north filter operated until switched, as noted above, at
submergence between full and half-full, and vacuum of 3 to 9
inches Hg. The south filter operated from period 8 on, as noted
above, at submergence between full and 12 inches from the top, and
vacuum of 8 to 11.5 inches Hg.
Sample No. 11 was not taken: the south filter was shut down to
clean the drum. The counters on the sludge pumps were switched
because the numbers could not be read.
Faulty filtrate meter readings were reported to be caused by air
in the filtrate from washing the drum with soap, or from C02 gas
caused by mixing low pH clarifier underflow with waste lime.
Underflow was taken in for about 2.5 hours during the first shift.
Underflow was taken in for about 2.5 hours during the third shift.
The south filter operated, except as noted above, at submergence
between full and 6 inches from the top, and vacuum of 7 to 12
inches Hg.
12/22/76 Full sampling at all stations. The sludge pumps were switched to
repack the west side of the west pump, and the filters were switched
without shutdown of the plant.
Faulty flow meter readings were reported to be caused by excessive
foaming due to low-pH clarifier underflow and the factory manager
was asked to raise the pH to above 8.0. Underflow was taken in
for about 4 hours during the first shift, through most of the
second shift, and for about 4 hours during the third shift.
The south filter operated through period No. 3 at full submergence
and vacuum of 5.5 to 10 inches Hg. The north filter operated, for
the balance of the day, at submergence full to 10 inches from the
top, and vacuum of 4 to 10.5 inches Hg.
12/23/76 Full sampling at all stations. Replaced water and sludge packing
and repaired an oil leak on the east sludge pump. Switched to the
south filter to wash the north filter. Connected a 1/2-inch pipe
to the filtrate line. Reset the east pump counter and placed
covers over the counters (humidity had caused condensation on
counter windows). Installed an air relief valve on the sludge
line. Moved the polymer pump to the catwalk and placed injection
point at the elbow. Tightened the sludge sampling valve.
The filtrate flow meter was still giving fault or very high and
unreliable flow readings. Underflow was taken in for about 3
90
-------
12/24/76
12/26/76
12/27/76
hours during the first shift, 5.5 hours during the second shift,
and 5 hours during the third shift.
The south filter operated all day, at submergence full to half-full,
and vacuum of 3 to 11.5 inches Hg.
No samples were collected during the third shift, but no reason
was given. The bolts on the north drum agitator were tightened.
The sludge pump counter was cleaned and reset. The drums were
switched for cleaning. It was reported that sand in the clarifier
caused the pipe to plug between 10:00 a.m. and 12:30 p.m. and
again around 6:00 p.m.
Underflow was taken in for about 7 hours during first shift,
through most of the second shift, and for about 5 hours of third
shift.
The filtrate flow meter was still not working:
found on the vacuum tanks.
air leaks were
The south filter operated, except as noted above, at submergence
between full and one-third full, and vacuum of 7 to 11 inches Hg.
Sample No. 9 was not taken: the filter was shut down to wash the
drum cover. The vacuum gauge on the north filter dropped to 0 at
3:45 a.m. and the operator was unable to get any response.
The filtrate flow meter did not produce any reliable data.
Underflow was taken in for about 6 hours during the first shift, 4
hours during the second and 4 hours during the third shift.
The north filter operated, except as noted above, at submergence
full to three-fourths full, and vacuum of 3 to 11.5 inches Hg
except when not measured as noted above.
Sample No. 9 was not taken: the Mud House was shut down to wash
the filter canvas. The west sludge pump was started because of a
bad leak on the east sludge pump packing. Eight oz of polyelectro-
lyte per 50 gal were added for 2 hours. An attempt was made to
man both filters: the experiment was halted after two hours
because the operator reported being unable to keep up.
No filtrate flow data were entered. Underflow was taken in for
about 3 hours during the first shift, 3 hours during the second
shift, and 1 hour during the third shift.
The north filter operated, except as noted above, from 11:00 a.m.,
at submergence between full and one-third full, and vacuum of 5 to
12 inches Hg. The south filter operated also, during periods 1
(by itself) and 4 (concurrently), at full submergence and vacuum
of 2 to 7 inches Hg.
91
-------
12/28/76 Sample No. 11 was not taken: a bad packing on the north filter
prevented switching the filters and the Mud House was shut down to
wash the south filter; started the day with the north filter and
switched to the south filter to wash the former at 5:00 p.m.; the
need for more frequent filter washings was blamed on a possible
overdose of polymers during tests from the previous day. Sand
found in the clarifier was traced back to a bypass valve inadver-
tently left open on the classifier at the Beet Handling House.
The waste lime was reported cold and wet.
No filtrate flow data were recorded.
Underflow was taken in for about 4 hours during first shift, 1
hour during the second shift, and 2 hours during the third shift.
The north filter operated, as noted above, at submergence between
4 and 12 inches from the top, and vacuum of 11 to 15 inches Hg.
The south filter operated, as noted above, at submergence between
full and 6 inches from the top, and vacuum of 4 to 12 inches Hg.
12/29/76 Sample No. 12 was not taken but no reason was given. Replaced the
packing on the north drum vacuum line and switched to it during
periods 7 and 8; worked on the polyelectrolyte pump and added 12
oz polyelectrolyte per 50 gal for 2 hours; switched the sludge
pumps at 1:00 a.m. when the west pump lost its packing.
The filtrate flow meter was installed on the intake line to the
pumps and started to produce flow data; the flow rate was calcu-
lated at 49.3 gpm for 13 hours of operation. Underflow was taken
in for about 4 hours during the first shift, 4 hours during the
second shift, and 2 hours during the third shift.
The north filter operated, as noted above, at submergence between
full and three-fourths full, and vacuum of 3 to 11 inches Hg. The
south filter operated throughout the day, except as noted above,
at submergence between full and 12 inches from the top, and vacuum
of 5 to 10 inches Hg.
12/30/76 The first three samples were not taken; the Mud House was shut
down at the beginning of the day until 3:00 p.m. by repair work on
high-voltage lines by the power company. The north drum was down
to repair broken packing gland on the vacuum line: an air leak
was found on the vacuum pump packing. Repacked the west side of
the west sludge pump. (Sample 8 was not taken, but no reason was
given.).
The filtrate flow meter data yielded a calculated flow rate of
30.6 gpm for 16 hours of operation. Underflow was taken in for
about 3 hours during the first shift, 6 hours during the second
shift, and 4 hours during the third shift.
92
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The south filter operated, except as noted above, at submergence
between full and 12 inches from the top, and vacuum of 5 to 10.5
inches Hg.
12/31/76 Full sampling at all stations.
A filtrate flow rate of 27.3 gpm for 22 hours of operation was
calculated. Underflow was taken in during most of the first
shift, for about 6 hours during the second shift, and very little
or none during the third shift.
The south filter operated at submergence between full and half-full
and vacuum of 4 to 11 inches Hg.
Comment: An unusual day with no filter washes reported. This,
coupled with a steady filtrate flow rate and a high filtrate
temperature of 29°C to 34°C, led to the conclusion that minimal
amounts of underflow were processed.
1/2/77 Full sampling at all stations. Began filtering with the south
filter then switched to the north filter at 10:00 a.m., and back
to the south filter at 7:00 p.m. (suspect filter washing as reason
for switching).
A filtrate flow rate of 36 gpm for a 24-hour period was calculated.
Underflow was taken in for about 2 hours during the first shift, 1
hour during the second shift, and 1 hour during the third shift.
The north filter operated, as noted above, at submergence between
full and 6 inches from the top, and vacuum of 6 to 8 inches Hg.
The south filter operated, as noted above, at submergence between
full and 3 inches from the top, and vacuum of 5 to 7 inches Hg.
1/3/77 Underflow samples No. 2 and 3 were not taken: the clarifier was
shut down between 10:30 a.m. and 1:45 p.m.; the pump's variable
speed control was jammed. The clarifier shutdown caused the
submergence level in the north filter to drop to a low level.
Power was lost for about 2 minutes, at 11:05 a.m., due to a blown
transformer at the power station. Switched to the north filter at
8:40 a.m., switched to the south filter at 8:00 p.m. and back
again to the north filter at 6:00 a.m. (suspect filter washing as
reasons for switching).
A filtrate flow rate of 19.6 gpm for 8 hours of operation was
calculated. Underflow was taken in for about 7 hours during the
first shift, 6 hours during the second shift, and 3 hours during
the third shift.
The north filter operated, as noted above, at submergence between
full and 8 inches from the top, and vacuum of 3 to 14 inches. The
south filter operated, as noted above, at full submergence, and
vacuum of 5 to 14 inches Hg.
93
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1/4/77 The first four samples were not taken: the Mud House was shut
down from 9:00 a.m. to 4:30 p.m. for flow measurement trials by
S&P. A broken stud on the sludge pump was replaced and an oil
leak was repaired. (The second shift started filtering with the
north filter, then switched to the south filter at 7:00 p.m. and
back to the north filter at 1:00 a.m., apparently to wash the
filters.)
A filtrate flow rate of 27 gpm for 8 hours of operation was calcu-
lated. Underflow was taken in for about 4 hours during the second
shift and about 4 hours during the third shift.
The north filter operated, as noted above, at full submergence,
and vacuum of 5 to 12 inches Hg. The south filter operated, as
noted above, at submergence between full and three-fourths full,
and vacuum of 9 to 15 inches Hg.
1/5/77 The first four samples were not taken: the Mud House was shut
down to allow for calibration of underflow pump and bypass valve.
The second shift began filtering with the north filter, then
switched to the south filter at 7:00 p.m. and back to the north
filter at 3:00 a.m. (apparently to wash the filters).
A filtrate flow rate of 36.7 gpm for 10 hours of operation was
calculated. The manufacturer returned the underflow flow meter to
the site. An attempt was made to install it on the section of
pipe leading to the mixing tank, but aeration, when opening the
bypass valve, caused the meter to malfunction. The meter was then
reinstalled at its previous location, but after several hours of
observation, it was concluded that solids in the underflow made
this liquid immeasurable by this method. The data on the estimates
of underflow taken in were inconclusive.
The north filter operated, as noted above, at submergence between
full and 8 inches from the top, and vacuum of 7 to 14 inches Hg.
The south filter operated, as noted above, at submergence between
full and 24 inches from the top, and vacuum of 5 to 8 inches Hg.
1/6/77 Samples No. 2 and 3 were not taken: the Mud House was shut down
because no waste lime was available from the factory. Sample No.
5 was not taken: both filters were washed and switched to the
south filter; then back to the north filter to clean the south
filter at 10:00 p.m. (no shutdown). The east sludge pump blew a
seal, causing mud to spray onto the floor; replaced the oil ring
and a valve stem. '
' I
A filtrate flow rate of 22 gpm for 6 hours of operation was calcu-
lated. Underflow was taken in for about 2 hours during the first
shift and for about 2 hours during the second shift. The third
shift did not record any information.
94
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The north filter operated, as noted above, at submergence between
full and half-full, and vacuum of 5 to 15 inches Hg. The south
filter operated, as noted above, at submergence between full and 8
inches from the top, and vacuum of 9 to 11 inches Hg.
Note to the Reader: Two types of accounts are presented in the
remainder of this log summary. The accounts for 1/8/77 and 1/9/77
conform to the format followed up to this point and are based on
data recorded by the Mud House operators. The other more detailed
information is described in the order of occurrence and as recorded
by an observer monitoring the activities of the first shift exclu-
sively.
1/7/77
8:00 a.m. The south filter was operating but the blower was failing:
the cake was not being properly blown from the filter cloth.
A sludge pump seal was out and sludge was being squirted onto
the floor. According to the foreman, it had been out from
one to two hours.
8:05 a.m. The south filter was shut down for sludge pump repairs. All
clarifier underflow and waste lime were being bypassed to
their respective ponds.
8:20 a.m. The sludge pumps were switched and the crew was preparing to
start filtering again with the north filter.
8:21 a.m. The welder started installation of a cyclone in the clarifier
underflow piping system. As the welding machine was plugged
into the wall receptacle, a circuit breaker blew up and all
electrical power was lost.
8:50 a.m. The fuse was replaced and electrical power was restored. It
appeared that the receptacle collected water from washing
down equipment and moisture within the building.
During the plant shutdown caused by the power outage, all
materials were bypassed to the outside. During this down
time, the filter cake froze partially in the discharge line,
causing a backup and overflow in the hoppers. During this
time, and with the sludge pumps discharging at full stroke,
an oil line in the hydraulic system broke and had to be
repaired.
10:00 a.m. The north filter was put in operation.
10:18 a.m. The east valve was set at 1-1/4", 25 gpm, clarifier pump set
at 30 percent. Almost immediately the valve was reopened to
bypass the underflow because of an apparent high volume of
waste lime coming from the factory. The waste lime was
95
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flowing at about 108 gpm and the flow rate appeared to vary
considerably.
11:15 a.m. The east valve was set at 1-1/4", 25 gpm, clarifier pump set
at 30 percent.
11:56 a.m. Collected samples.
12:15 p.m. With a filter drum submergence of one-half to three-quarters
full, the mixing tank's rear chamber began to overflow while
the liquid level at the main chamber was about one foot from
the top. The east valve was opened to bypass underflow.
Comment: The waste lime and underflow enter the rear chamber
of the tank and the interchamber flow is through the bottom
of the partition. The settling of the denser materials,
which must pass first, causes the uneven levels between the
two chambers with resulting overflowing of the rear chamber.
The waste lime flow rate was calculated at 108 gpm, and the
underflow at 25 gpm, clarifier pump set at 30 percent.
1:00 p.m. Collected samples.
2:00 p.m. Collected samples.
3:00 p.m. Operations were switched from the north filter to the south
filter. The east underflow valve was set at 1", 55 gpm,
clarifier pump set at 30 percent. The waste lime flow rate
was calculated at 81 gpm. The filter tanks had to be kept
half-full or less because of a bearing leak in the shaft.
Under the above conditions, the following was observed: 1)
The cake looked good; 2) It was necessary, for a short time,
to bypass some of the mix until the liquid levels in the
tanks were stabilized. This was probably caused by the leaky
bearing and the variation of waste lime flow. The levels
were stabilized, and no further adjustments were required; 3)
The filtrate flow rate varied from 20 gpm, when only waste
lime was processed, to 72 gpm when 55 gpm of underflow was
added; 4) The effective stroke on the sludge pump decreased
from minus 2" to minus 3".
3:25 p.m. Collected samples.
3:53 p.m. Collected samples. I
3:55 p.m. The east valve was set at 3/4", 95 gpm, clarifier pump set at
30 percent.
Under these new conditions, the following was observed: 1)
The cake still looked good; 2) Same as before; 3) The
96
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filtrate flow increased to about 100 gpm, but the flow meter
started to fault due to air bubbles created by the higher
flow. As aeration continued to occur, the flow meter went
into a steady fault condition that lasted until the end of
the shift; 4) The effective sludge pump stroke increased
from minus 3" to minus 2".
A filtrate flow rate of 23.3 gpm for 4 hours of operation was
calculated during the first shift; during the second and
third shifts it was 35.3 gpm for 12 hours of operation.
1/8/77 Samples No. 5 and 6 were not taken: the Mud House was shut down
to wash the filters. Began operations with the north filter;
switched to the south filter after the shutdown; switched back to
the north filter, without shutdown, at about 4 a.m.
A filtrate flow rate of 15.8 gpm for 16 hours of operation (shutdown
period excluded) was calculated. No data on underflow distribution
was recorded.
The north filter operated, as noted above, at full submergence,
and vacuum of 5 to 16 inches Hg. The south filter operated, as
noted above, at submergence between full and 4 inches from the
top, and vacuum of 8 to 9 inches Hg.
1/9/77 Samples No. 6, 7, and 8 were not taken: the Mud House was shut
down to wash the filters, repair a leaking water line on the east
sludge pump, repack a shaft on the west sludge pump, and to clean
the filter of one of the blowers. Began operations with the north
filter; switched to the south filter, without shutdown, at 1:00
p.m. and continued after the shutdown; switched back to the north
filter, without shutdown at 5:00 a.m. Broken air lines inside the
north filter were reported causing problems with the lifting of
the cake from the drum.
A filtrate flow rate of 25.9 gpm for 14 hours of operation (shutdown
period excluded) was calculated. Underflow was taken in for about
1 hour during the first shift and for about 1 hour during the
second shift; the third shift did not record any data.
The north filter operated, as noted above, at submergence between
full and half-full, and vacuum of 5 to 9 inches Hg. The south
filter operated, as noted above, at submergence between full and
three-fourths full, and vacuum of 7 to 9 inches Hg.
1/10/77
8:00 a.m.
The north filter was operating, but the blower was working
only on half of the drum. The two previous shifts had trouble
with the blowers on both filters.
97
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The previous shift was filtering waste lime only. The fil-
trate was reading 20 gpm and the effective stroke on the
sludge pump was minus 2". These conditions appeared to be
normal when processing straight waste lime.
The flow meter on the underflow line was no longer working.
Both drums were having bearing leaks. The foreman did not
want to start introducing underflow until repairs on the
blowers had been made. Everyone was busy with repairs and
the Mud House could not afford any additional problems at
this time. There was concern about freezing of the discharge
line.
9:00 a.m. The east valve was set at 1-3/4", (zero underflow), clarifier
pump set at 34 percent.
9:15 a.m. Collected samples. The clarifier operator did not show up,
and there was a buildup of about 4 feet of mud. The clarifier
pump was set at 34 percent to discharge more mud out of the
clarifier. The total flow out of the clarifier was estimated
at 180 gpm.
10:30 a.m. The crew was still working on the south filter. The north
filter was still processing straight waste lime.
Problems had been experienced in keeping the desired liquid
levels in the mixing tank and in the filters. The level
indicator must be flushed down periodically to avoid false
level readings due to clogging.
11:10 a.m. Started operating the south filter. The waste lime flow rate
could not be determined because the flow of waste lime to the
filter tank could not be cut off and all of it was needed to
keep the filter tank full.
11:14 a.m. The east valve was set at 1-3/4", 50 gpm, clarifier pump set
at 34 percent.
11:24 a.m. Collected samples. The filter cake was rather thin and wet,
the filter flow rate had increased to 60 gpm, and the effective
stroke on the sludge pump was reduced from minus 16" to minus
28".
11:40 a.m. The east valve was set at 1-1/2", 80 gpm, clarifier pump set '
at 34 percent. /
12:24 p.m. Collected samples. The filtrate flow rate had decreased from
60 gpm to 20 gpm, the cake was still coming out thin but dry,
and the effective stroke of the sludge pump had increased
from minus 28" to minus 24".
98
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1:00 p.m. Collected samples. The same conditions as the 12:24 time
prevailed.
1:35 p.m. The mixing tank and filter drum reached their maximum level.
Some of the mix from the mixing tank was bypassed to hold a
steady level. The bearing was still leaking even though the
filter drum had been running close to full.
2:00 p.m. Collected samples. Conditions remained unchanged. The
sludge pump developed a pressure seal leak. (See 1/7/77
notes for this same problem.) The bearing was still leaking.
2:10 p.m. The filter cake in the discharge line had frozen. The sludge
was being discharged into the pond through a valved tee near
the building. The crew was working to correct the problem.
It had become necessary to bypass the mix again. About 1,950
gals were bypassed each time.
2:20 p.m. The east valve was set at 1", 130 gpm, clarifier pump set at
34 percent. The quality of the filter cake seemed to improve:
it was still thin but drier and cutting better. (See final
note of the day for reason.)
2:38 p.m. The east valve was set at 3/4", 155 gpm, clarifier pump set
at 34 percent.
2:45 p.m. The filter cake discharge line broke at the tee connection
outside the building, making it necessary to stop filtering
and to bypass waste lime and underflow until repairs were
made.
3:30 p.m. The tee connection was repaired, but due to the prolonged
down time, the sludge had frozen in the line.
4:30 p.m. At the end of the shift, the sludge discharge line was still
frozen and the filters were still shut down. The filtrate
flow rate was calculated at 23.5 gpm for 5 hours of operation.
Comment: It was discovered that the clarifier pump had
changed percent load settings throughout the day. The operator
usually adjusts the setting, but since there was no one in
attendance, today's estimated clarifier flow rates are not
reliable. It was set at 34 percent around noon, and at 28
percent by 2:30, thus indicating that very little or no
clarifier underflow was taken in during that period.
1/11/77
8:00 a.m. The south filter was operating at the start of the shift.
The east valve was wide open and only waste lime was being
filtered.
99
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8:20 a.m. Collected samples. The filtrate flow was 30 gpm; clarifier
pump set at 34 percent; the effective stroke on one sludge
pump was minus 16".
11:15 a.m. Collected samples at 9:00, 10:00, and 11:00; conditions
remained similar to those reported at 8:20. All settings
were still the same. No underflow was being processed.
The flow of clarifier underflow into the mixing tank was
measured and compared to the setting on the east valve to
verify correctness of the flow chart: the chart was found to
be correct.
11:30 a.m. A decision was made by MINN-DAK not to process any underflow
on this date. Indications were that the clarifier underflow
lowered the temperature of the mix to a point where the cake
readily froze in the discharge line outside. This was sus-
pected for the line freezing yesterday. MINN-DAK suggested
that underflow be processed for a short period every 2 hours
to avoid freezing the discharge line.
12:00 p.m. Started operating the north filter. Both filters were working
but were having problems with the blowers. The cake was
being blown in the proper manner in only about one half of
the drum.
12:25 p.m. Collected samples.
1:00 p.m. The temperature of the waste lime as it discharged in the
mixing tank was 40°C. The temperature of the cake out of the
filter was 34°C. The outside temperature was -24°C.
1:50 p.m. Collected samples.
3:00 p.m. The cake had looked good up to this time, but the quality was
beginning to deteriorate.
3:15 p.m. Collected samples.
4:00 p.m. Collected samples. The filtrate flow was calculated at 47.3
gpm for 22 hours of operation.
Comment: The settled solids profile in the clarifier appears
to have peaks and valleys and the operator usually sets the
snout for the peaks only. This means that, as the snout
sweeps the clarifier, the mud sucked into the pump intake
exhibits a variable density: heavy through the peaks and
light through the depressions as more water is taken in.
100
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1/12/77
8:00 a.m.
12:15 p.m.
12:30 p.m.
2:00 p.m.
2:15 p.m.
2:23 p.m.
4:30 p.m.
1/13/77
8:00 a.m.
The north filter was operating at the start of the shift. It
had been running for 8 hours with only waste lime being
processed during this time. The quality of the cake appeared
poor and the filtrate meter read 20 gpm, about the normal
flow for straight waste lime filtration.
The clarifier operator did not show up again on this date.
The previous shift reported that the underflow pipe had been
plugging up often and attributed this to very dense mud being
sucked by a low setting of the snout.
Collected samples.
Switched operaton to the south filter. The east valve was
set at 1-3/4", 25 gpm, clarifier pump set at 32 percent; the
waste lime was calculated at 65 gpm; the outside temperature
was -27°C; wind 5-10 mph.
The mixing tank solution level was holding well; the cake was
a medium brown, .05' thick, and cutting well.
Collected samples.
The east valve was set at 1-1/2", 60 gpm, clarifier pump set
at 32 percent; the waste lime flow was calculated at 56 gpm;
the tank solution was holding well; the cake was dark brown,
.05' thick, not cutting as well as at 2:00, but still acceptable.
Were still processing the same ratio on the mix at the end of
the day. The quality of the cake had decreased to a point
where the filters would have to be switched soon.
The filtrate flow rate was calculated at 34 gpm for 7 hours
of operation.
Collected samples. The north filter was operating but no
clarifier underflow was being processed. The filter had been
running since about 5:00 a.m., and only the east one-third of
the filter had been producing a good cake. It was determined
that the pipe feeding the west end of the tank had plugged.
The cake began to deteriorate at the center of the filter.
(Under normal conditions, the denser material separates from
the water near the point where the mix is introduced at both
ends of the tank; therefore, there are less solids at the
center of the filter than at either end; in addition, a thin
slurry containing sand is pumped up and is applied at the top
center of the drum.)
101
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It was observed that when clarifier underflow was introduced
in the mix, the filter would produce a good cake for a limited
time only.
9:00 a.m. Collected samples.
9:30 a.m. The cyclone was put in operation for a short time.
10:00 a.m. Collected samples.
11:20 a.m. Collected samples. The east valve was set at 1-1/4", 100
gpm, clarifier pump set at 32 percent; waste lime flow was
calculated at 71 gpm.
12:10 p.m. Collected samples. The filtrate flow meter read 60 gpm; the
cake had a dark gray color, high moisture content, but appeared
solid and cutting well; the volume in the mixing tank was
slowly increasing.
12:25 p.m. The cake was steadily getting thinner and wetter; the east
valve was set at 1-1/2", 60 gpm, clarifier pump set at 32
percent.
1:00 p.m. Collected samples. The waste lime flow was calculated at 90
gpm, and the total flow to the mixing tank was estimated at
150 gpm.
2:00 p.m. Collected samples.
2:30 p.m. The bolts holding the face plate on the end of the drive
shaft to the filter frame were sheared off. This marked the
end of monitoring of the Mud House because MINN-DAK decided
to bypass the total underflow for the balance of the campaign.
Waste lime would continue to be filtered until the end.
4:00 p.m. The filtrate flow rate was calculated at 20.6 gpm for 8 hours
of operation.
END
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APPENDIX C
MONITORING AND ANALYTICAL PROGRAMS
SAMPLE COLLECTION AND ANALYSIS, AND QUALITY CONTROL
Campaign Period Sampling Procedures
Sample aliquots were collected every odd-numbered hour and com-
posited into daily samples Monday through Saturday each week of the study.
Each Mud House shift operator was responsible for entering data in the Mud
House log and seeing that sample aliquots were collected. Each morning
MINN-DAK personnel took the filtrate (F), clarifier underflow (CU), filter
cake (FC), and cake storage area (CSA) samples to the MINN-DAK laboratory.
The waste lime (WL) sample aliquots were collected in the plant and com-
posited in the laboratory by MINN-DAK laboratory personnel.
Specific instructions for the collection of each type of sample
were provided to the operators. Demonstrations of sampling technique were
also performed.
None of the samples were preserved before analysis. In general,
analyses were started nine to ten hours after the last sample aliquot was
added to the composite sample.
Procedures—
The analytical procedures used were:
1. COD. Total and Soluble—The procedure followed is published in
section 508, pp. 550-554, "Standard Methods for the Examination of Water and
Wastewater," 14th ed., APHA, AWWA, WPCF (1975) (abbreviated SMEWW). The
quantities of reagents used were those given in Table 508:1 on page 553 of
the above reference, for a 20.0 tal sample size. For COD values greater than
1000 mg/1, a suitable portion of sample was diluted to a known volume with
distilled water.
The soluble COD was determined by the above procedure on the
filtrate obtained by filtration of a sample aliquot through a 0.45 micron
(pore diameter) membrane filter. This definition of the soluble or dissolved
fraction of a constituent is found on page v of "Methods for Chemical Analysis
of Water and Wastes," USEPA (1974), document number EPA-625-/6-74-003.
2. Calcium, Total and Soluble—Calcium was measured by titration
with EDTA according to the procedure of section 306C of SMEWW.
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3. pH Values—The pH values of the samples were measured with an
electronic pH meter which employed a glass electrode and was equipped with
temperature compensating circuitry. Commercially available buffers were
used to calibrate the instrument. The procedure is published on pages
460-465 of SMEWW.
4. Temperature—Sample and ambient temperatures were measured
with a stainless steel dial thermometer with 1°C divisions.
5. Total Solids (TS) and Total Volatile Solids (TVS)—Total
solids were determined by a gravimetric procedure similar to that in section
208A of SMEWW. A 3-5 g sample was dried overnight in a mechanical convection
oven operated at 105-110°C.
To determine TVS, the TS sample, after cooling and weighing, was
ignited at 550°C for one hour. No decrepitation of sample was observed.
6. Bulk Density—Bulk density was determined by weighing a
measured volume of sample. The samples were measured by filling a porcelain
crucible; the volume of the crucible was determined by filling with water
and weighing.
Quality Control—
1. COD—A standard KHP solution was analyzed daily. One sample
per day was analyzed in duplicate so that, in the course of a week, one
sample from each sample stream was analyzed in duplicate.
2. Calcium—The same program of duplicate analyses used for COD
was also followed for the calcium determinations.
3. pH—The pH meter used was standardized daily with commercial
buffers.
4. Total Solids (TS) and Total Volatile Solids (TVS)—The same
program of duplicate analyses followed for COD was also followed for the TS
and TVS analyses.
5. Bulk Density—Bulk density was determined in triplicate daily
for each of the four samples (CU, EC, CSA, WL).
6. EPA Reference Samples—A duplicate set of EPA reference samples
was analyzed for total COD, pH, and total dissolved solids by Sverdrup &
Parcel (S&P). The analyses were performed by an S&P chemist at its St.
Louis, Missouri laboratory, and by a technician at the MINN-DAK laboratory
in Wahpeton, North Dakota. The results obtained are presented in Table C-l
below.
104
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TABLE C-l. QUALITY CONTROL RESULTS
Value Reported By
Parameter
Total COD, mg/1
Total COD, mg/1
pH , units
pH, units
TDS, mg/1
TDS, mg/1
Sample
Number
1
2
1
2
1
2
EPA S&P Chemist
Corvallis, OR St. Louis, MO
770
2,310
7.7
8.6
717**
3,180**
774
2,210
7.85
7.98
680#
3,640#
S&P Technician
Wahpeton, ND
750
g.t. 1,900*
8.30
8.25
935#
3,640#
*
g.t. signifies greater than
** Dried at 180°C
# Dried at 103-105°C
105
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APPENDIX D
MUD HOUSE OPERATING LOG
SAMPLING INSTRUCTIONS
1. General
Each shift operator will be responsible for making entries in the
appropriate spaces provided, and at the required two-hour intervals.
The odd-hour intervals are guides only but should be adhered to as
closely as possible. Any deviations should be noted in the "Comments"
block.
2. Date
The first shift operator will enter the date. The second and third
shift operators will insure that this entry is made and that it is
entered correctly.
3. Time of Entry
All time recordings will be made from the same Mud House clock or from
timepieces synchronized with it.
4. Mud House Ambient Temperature
Record ambient temperature by reading the thermometer provided at the
filtrate return sampling station. Record temperature to the nearest
1°C. Record time to the nearest 5 minutes.
5. Liquid Sample Collection
This applies to the Thickener Underflow and the Filtrate Return sampling
stations. Each station will have the following equipment: flow meter,
thermometer, waste bucket, collecting bucket, measuring bottle, funnel,
stirrer and sample container. Collect the sample according to the
following procedure:
5.1 Open sampling valve and waste about 1/2 gallon in waste bucket.
5.2 Collect about 3/4 gallon sample in the sampling bucket; close
valve.
5.3 Dip in and fill 1/2 pint measuring bottle immediately. If this is
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not done immediately, and/or if solids begin to settle, stir the con-
tents of the sampling bucket prior to filling the measuring bottle.
5.4 Immerse the thermometer in the sampling bucket.
5.5 Pour half of the sample in the sampling bottle into the sample
container with the aid of the funnel. Swirl the remaining half to
insure complete mix and pour in the sample container. Except during
sample collection times, the sample container should remain capped.
5.6 Read the thermometer and record the temperature of the sample in
the log to the nearest degree. Wipe the thermometer.
5.7 Read the flow meter and record flow rate, total gallons and time,
to nearest 5 gpm, 100 gallons, and one minute, respectively.
5.8 Proceed to the next task. Do not pause to clean equipment until
all other data collecting and recording tasks have been completed.
6. Lagoon Valve
Record the times at which the valve diverting thickener underflow to
the lagoon is opened and closed, to the nearest minute. Record the
aperture of the valve; record number of turns; or if valve is a rising
stem type, measure and record the height of the valve stem.
7. Filter Operation Data
The filters are identified as north and south filters. Record in the
log the seconds it takes the drum to complete one revolution, the
inches out of the liquid level, the vacuum applied in inches of mercury,
and the time at the completion of the readings. Proceed to obtain the
cake sample.
8. Filter Cake Sampling
Stations will be marked to indicate four points at which samples will
be obtained. Sampling equipment will include a long-handled spoon to
reach the cake as it is dislodged from the filter, and a wide-mouth
plastic jar to collect the cake samples. Collect cake samples by
filling spoon and deposit contents into the jar. This procedure will
be demonstrated during the first week of sampling. The container will
be kept tightly closed between collections to prevent the drying of the
cake.
9. Cake Storage Sampling
Obtain cake storage sampling from the self cleaning sampling valve
located downstream from the sludge pumps. A sampling ladle and a
wide-mouth plastic jar sample container are provided. Collect sample
by filling the ladle and deposit contents into the jar. Keep jar
tightly closed between sample collections.
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10. Sludge Pumps
Stroke counters will be installed on the sludge pumps. Record the
times at which the pumps are turned on and off and record the pump
count and setting and/or the volumetric displacement of the setting;
record only the initial (9 a.m.) and final (7 a.m.) counts and settings.
11. Polyelectrolyte
MINN-DAK, on its own initiative, is presently experimenting with poly-
electrolytes. Record the times polyelectrolyte is added to the mixing
tank (on and off), the feed rate (gal/hour or convenient units), the
concentration (weight/volume or convenient units) and the type of
polyelectrolyte. Note any changes on any of the above and record.
12. Cleaning of Sampling Equipment
After all sampling collection and data recording have been properly
carried out, proceed to clean sampling equipment in preparation for the
next collection. Dump excess sample and rinse sampling bucket,
measuring bottle, and funnel. Clean cake sampling device.
13. Comments
Enter here any unusual activities not reflected under itemized instruc-
tions. Special attention should be given to breakdown of equipment.
Record any changes in operation and reasons for them.
14. Waste Lime Sampling
Waste lime samples will be collected at the factory by laboratory
personnel on the same schedule as the Mud House. Samples are routinely
collected by a laboratory technician, who will collect enough samples
to make the composite for the analysis of this stream.
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GLOSSARY
anaerobic: Living or active in the absence of free oxygen.
beet pulp: The vegetable matter left after sugar is extracted from cossettes.
beet wheel: A large wheel with baffles projecting radially inward from the
surface of the perforated rim, and used to raise beets to a higher
plane and separate them from the flume water; e.g., as from a flume to
a beet washer.
biochemical oxygen demand (BOD5J: A measure of the oxygen demand in sewage
and industrial wastes or in a stream, determined by bioassay techniques.
campaign: The period of the year during which the beet plant makes sugar.
clarification: The process of removing undissolved (suspended) materials
from a liquid. Specifically, the removal of solids by settling.
COD: Chemical oxygen demand. A measure of the oxygen demand equivalent of
that portion of matter in a sample that is susceptible to oxidation by
a strong chemical oxidant.
filtrate: Liquid after passing through a filter.
filtration: Removal of solid particles from liquid or particles from an air
or gas stream by a permeable membrane or layer of granular material.
flume wastewater: The term normally applied to the discharge of flume water
that is employed to convey beets into the beet sugar processing plant.
lime cake: The residue resulting from clarification and purification of the
raw sugar juice by heating, lime addition, and precipitation in a
two-step process through carbon dioxide addition. The cake contains
both organic and inorganic impurities.
lime mud slurry: The product resulting from the addition of water to lime
cake to facilitate pumping of the material for disposal.
lime pond: A large diked area in which lime mud slurry or waste filter
cakes are held.
pH: A measure of the relative acidity or alkalinity of water. A pH value
of 7.0 indicates a neutral condition; less than 7 indicates a predomi-
nance of acids; and greater than 7, a predominance of alkalis. There
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is a 10-fold increase (or decrease) from one pH unit level to the next,
e.g., 10-fold increase in alkalinity from pH 8 to pH 9.
sedimentation: The falling or settling of solid particles in a liquid, as a
sediment (clarification).
slicing capacity: Processing capacity. The number of tons of sugar beets a
plant is capable of processing in a 24-hour period of time.
sludge: The settled mud from a thickener or clarifier. Generally, any
flocculated, settled mass.
Steffen process: A process employed at some beet sugar plants for recovery
of additional sucrose from molasses. The process is carried on in
conjunction wth the main sugar extraction process at non-Steffen or
"straight-house" plants. The process consists of the addition of
finely ground calcium oxide to dilute molasses under low temperature
conditions. Sugar, Steffen filtrate, and insoluble calcium saccharate
are produced, filtered out, and generally reused at the main purifica-
tion step of the normal "straight-house" extraction process.
supernatant: The liquid layer floating above the surface of a layer of
solids or sludge.
total suspended solids (TSS): Solids found in wastewater or in the stream
which in most cases can be removed by filtration. The origin of sus-
pended matter may be man-made wastes or natural sources such as silt
from erosion.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA-600/2-80-089
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
EVALUATION OF FULL-SCALE SUGAR BEET TRANSPORT
WATER SOLIDS DEWATERING SYSTEM
5. REPORT DATE
May 1930 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
M.F- Figueroa, F.A. Brunner, F.S. Williams,
and J.C. Buzzell, Jr.
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Sverdrup & Parcel and Associates, Inc.
801 North Eleventh
St. Louis, Missouri 63101
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
68-01-3289
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final Report 9/76-10/78
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The objectives of this study were to evaluate a full-scale vacuum filtration
system for dewatering solids removed from the transport water in an operating beet
sugar plant in terms of operational reliability and efficiency, economics, and ultimate
disposal of the dewatered solids.
At the plant study site (MINN-DAK Farmers Cooperative, Wahpeton, North Dakota),
the solids in the beet transport water are removed in a clarifier and piped to the Mud
House. Waste lime mud from the sugar processing is added to the clarifier underflow to
serve as a filter aid. The combined sludge is dewatered on two vacuum filters. The
filter cake is pumped to a storage lagoon adjacent to the Mud House.
Study findings indicate that the solids handling system was not functioning as
intended, largely because the clarifier did not provide sufficient thickening. The
vacuum filters received primarily waste lime mud; the clarifier underflow largely by-
passed the Mud House and went directly to a storage lagoon. Mud House operations were
adjusted to compensate for the various difficulties, resulting in bypass of most of
the clarifier underflow.
Because the solids handling system was not functioning as intended, the economic
evaluation was not carried out. Instead, the various components of the total system
were evaluated and modifications are presented that can be implemented to improve the
system so that the original goals for the system can be achieved.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATl Field/Group
Sugar beets
Sludge disposal
Sludge drying
Vacuum filtration
Sedimentation
Clarification
Lagoons
Odors
Odor detection
Flume solids
Closed loop
Lime mud
North Dakota
MINN-DAK Farmers
Cooperative
02 A
06 H
13 B
13 K
14 D
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report I
UNCLASSIFIED
21. NO. OF PAGES
121
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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