Report on Reevaluation of the
1977 Effluent Limitations for
the Hilo-Hamakua Coast
of the
Island of Hawaii
Raw Cane Sugar Processing Subcategory
Douglas M. Costle
Administrator
.Robert B. Schaffer
Director, Effluent Guidelines Division
William M. Sonnett
Project Officer
November 1979
Effluent Guidelines Division
Office of Water and Waste Management
U.S. Environmental Protection Agency
Washington, D.C. 20460
3TERS LIBRARY
MENTAL PROTECTION AGENCY
'•'ON, D.C. 20460
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ABSTRACT
This report presents the findings of a study of the Hilo-Hamakua Coast
raw cane sugar processing subcategory for the purpose of reevaluating
the effluent limitations guidelines for the subcategory. The findings
are in answer to the notice of suspension at 43 FR 43394, September
25, 1978.
The Agency is recommending revised effluent limitations guidelines for
suspended solids control. These are based on the degree of effluent
reduction attainable through the application of the best practicable
control technology currently available (BPT). This technology
includes screening and grit removal, clarification with polymer
addition, and settling in a clarifier followed by thickening and land
spreading of the settled solids. A series of gravity settling ponds
is reported to be a satisfactory alternative.
The study presents the supporting data and rationale for the
recommended suspended solids effluent limitations.
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TABLE OF CONTENTS
Section
I CONCLUSIONS
II RECOMMENDATIONS
III BACKGROUND
IV CURRENT STUDY
V WASTEWATER TREATMENT SYSTEMS
VI CANE HARVESTING AND WASTE LOAD
VII BASIS FOR BPT LIMITATIONS
VIII COSTS
Page
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SECTION I
CONCLUSIONS
EPA's review of the available data on waste treatment within the three
plants in the Hilo-Hamakua Coast sugar processing subcategory
confirmed that the technology originally recommended for the industry
is still appropriate. This technology includes end-of-pipe
clarification to remove suspended solids, vacuum filtration to dewater
the settled sludge, and land spreading to dispose of the thickened
sludge.
Review of the data indicates that the original BPT total suspended
solids limitations should be revised to better reflect the situation
at the Hilo-Hamakua Coast factories. The limitations are based on
quantity of gross rather than net cane processed. The use of gross
rather than net cane more accurately accounts for the amount of soil
and debris brought into the factories with the cane and the impact of
the soil and debris on the process wastewater suspended solids
loading. The pH of the process wastewaters from the Hilo-Hamakua
Coast factories is not being controlled because of insufficient data.
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SECTION II
RECOMMENDATIONS
The Agency is recommending revised BPT effluent limitations for the
Hilo-Hamakua Coast raw cane sugar processing subcategory based on end-
of-pipe treatment of process wastewaters and based on a gross cane
measurement of raw material. The BPT technology is already in place
at two of the three Hilo-Hamakua plants. An alternative system, in
use at the third plant, is expected to be able to attain the revised
BPT effluent limitations set forth below.
Maximum for Any One Day Average of Daily Values
Effluent for 30 Consecutive Days
Characteristics Shall Not Exceed
ko Ib kg Ib
kkg gross 1000 Ib gross kkg gross 1000 Ib gross
cane cane cane cane
BODS No limitations No limitations
TSS~ 9.9 9.9 3.6 3.6
pH No limitations No limitations
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SECTION III
BACKGROUND
On February 27, 1975, EPA promulgated an interim final effluent
limitations guidelines regulation for the following raw cane sugar
processing subcategories: Louisiana (Subpart D); Florida and Texas
(Subpart £); the Hilo-Hamakua Coast of the Island of Hawaii (Subpart
F); Hawaii (Subpart G); and Puerto Rico (Subpart H). Simultaneously,
the Agency proposed BAT limitations, standards of performance for new
sources, and pretreatment standards for existing sources and new
sources. A development document for interim final regulation and a
supplementary economic analysis of the possible effects of the
regulation were issued to supplement the information in the
regulation. The Agency requested comments on the two supporting
documents.
On January 10, 1977, EPA suspended until March 1, 1978 that part of
the interim final BPT regulation pertaining to the Hilo-Hamakua Coast
of the Island of Hawaii (Subpart F) so that EPA could reevaluate the
technical aspects.
The time frame of this initial suspension was insufficient to complete
the data collection and analysis, and on September 25, 1978 the Agency
extended the suspension of BPT regulation for this subpart until May
30, 1979.
The EPA has completed its review of all information relating to this
matter, including information gathered in field investigations by
EPA's National Enforcement Investigations Center and industry
submissions.
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SECTION IV
CURRENT STUDY
On July 31, 1978, Region IX of the Environmental Protection Agency
requested new data from the industry under section 308 of the Clean
Water Act. The data was to be used to re-evaluate best practicable
technology currently available (BPT).
Industry submitted information covering the development and operation
of wastewater treatment facilities. Included were descriptions of the
water pollution control facilities, data covering waste treatment
performance and operation, and the capital, operation and maintenance
costs for water pollution control for the Honokaa Sugar Company,
Hamakua Sugar Company (formerly Laupahoehoe Sugar Company), and the
Hilo Coast Processing Company, Pepeekeo factory. Data was also
provided on the soil and rainfall characteristics for the Hilo-Hamakua
Coastal area.
Additional engineering field evaluation reports were completed for
this study by the EPA National Enforcement Investigations Center
(REIC) in Denver. These studies detailed plant investigations made by
NEIC during the period October 24 through 31, 1977. Compliance
monitoring reports and plant visit information also were submitted by
Region IX and the Hawaii Department of Health.
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SECTION V
WASTEWATER TREATMENT SYSTEMS
Total suspended solids (TSS) was the process wastewater pollutant of
most concern in the initial BPT limitations. Two distinct approaches
to the treatment of this pollutant have been taken by the three Hilo-
Hamakua Coast factories. Two of the mills, Honokaa and Hamakua, now
operate treatment systems consisting of preliminary screening and grit
removal, followed by clarification in a circular clarifier using
polymer flocculent aid. Settled solids from the clarifier flow to two
vacuum filters for thickening. Sludge is retained in ponds when
solids loadings are too heavy for the vacuum filters to handle. Final
treatment consists of land spreading the thickened solids.
The initial treatment design began operating at Honokaa in July 1976
using only one vacuum filter, 10 feet in diameter by 20 feet long.
This proved inadequate to handle the settled solids loading produced
when the fine screens located ahead of the clarifier failed.
The failed screens were replaced with a mechanical grit separator
consisting of a trough through which the wastewater flowed and through
which scraper boards passed. The separator can remove about 8 percent
of the suspended solids compared with 50 percent removal by the fine
screens. With the additional solids passing to the clarifier, the
single filter could not handle the loading. By the 1978 growing
.season, the plant had installed mud ponds to receive underflow from
the clarifier to accommdate excessive solids load in the system, and
added another vacuum filter to the system. Treatment performance has
since been consistently reliable.
Hamakua's treatment system began operating in July, 1977, complete
with four auxiliary mud ponds. A second vacuum filter was installed
in May, 1978. Treatment performance has been the best of any of the
mills.
The Pepeekeo factory took a completely different approach to the
treatment of process wastewater. The company has a land treatment and
disposal system which consists of large settling ponds assisted by a
polymer flocculant aid. Past performance of the system has been
unrealiable, largely because of belated mud and silt removals from the
ponds and the incorrect location of the flocculant aid feed point. To
correct these problems, the plant has expanded the pond system,
acquired additional solids handling equipment, and relocated the
polymer feed point.
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SECTION VI
CANE HARVESTING AND WASTE LOAD
Soil, the principal source of TSS in the wastewater, enters the
factory with the harvested cane. The amount of soil brought into the
factory is a function of the harvesting methods and rainfall
conditions prior to harvesting.
The basic harvesting methods use "push rake" and "V-cutter" bulldozers
with heavy rake-like or snow plow-like attachments. These can
function in the wettest conditions and in the steepest and rockiest
terrain; however, they also pick up large quantities of soil along
with the cane. In dryer weather and on relatively level, rock-free
terrain, more sophisticated mechanical harvesters can be used. These
cut the cane with rotating knives and remove it with much less soil
and roots. If the weather is dry, the cane can be burned, further
reducing the pick up of cane trash and associated soil. All of these
harvesting methods leave rows of piled cane which are subsequently
loaded into hauling trucks. A more advanced harvesting method uses a
mechanical harvester to cut the cane, clean and chop it into short
pfeces, and load it into a buggy which is driven alongside the
harvester. Cane harvested by this system does not need wet cleaning
at the mills. However, numerous technical difficulties have precluded
large-scale application. The mechanical harvesters are not usable
under wet conditions or on steep or rocky terrain. In addition, push-
rakes or V-cutters must clear strips around the borders of the fields
to give the harvesters room to maneuver.
Reducing non-mi liable material in the harvested cane provides the
following benefits:
1. reduction in the number of trucks required to haul cane by 50
percent;
2. elimination of cane cleaning, the most expensive factory
operation;
3. elimination of sugar losses of 15% or more from cane cleaning;
4. reduction in factory milling costs by at least 50%;
5. elimination of the need to dispose of over one million tons per
year of waste material;
6. reduction in power plant maintenance costs; and
7. reduction of maintenance costs, from transportation through sugar
storage.
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SECTION VII
BASIS FOR BPT LIMITATIONS
Background
The original effluent guidelines study for the Hilo-Hamakua Coast
subcategory defined best practicable control technology currently
available in the original Development Document, pages 191-192. This
technology was based on engineering judgment, technology transfer, and
laboratory information developed by the industry. The technology
included clarification of the process wastewaters with polymer
addition, followed by dewatering of the settled sludge, and disposal
of the thickened solids. (Barometric condenser cooling water and
excess condensate bypass the treatment system.) The design assumes
grit removal, polymer addition and mixing, settling in a heavy-duty
clarifier, dewatering sludge by vacuum filtration, and land spreading
of the solids.
The use of gravity settling ponds for clarification is an alternative
now in use at the third factory. EPA's review has shown that the BPT
technology on which the original effluent limitations were based is
still acceptable. It is now in use at two of the three Hilo-Hamakua
Coast factories and is the basis for the revised guidelines.
The original BPT effluent limitations for the Hilo-Hamakua Coast
subcategory were as follows:
Effluent
Characteristics
Maximum for Any One Day
Average of Daily Values
for 30 Consecutive Days
Shall Not Exceed
kq
kkg net
cane
Ib
1000 Ib net
cane
ko
kkg net
cane
Ib
1000 Ib net
cane
BOD5
TSS
pH
No limitations No limitations
4.2 4.2 2.1 2.1
Within the range 6.0 to 9.0.
Revised Limitations and Rationale
EPA is revising the BPT effluent limitations for the Hilo-Hamakua
Coast subcategory as follows:
Effluent
Characteristics
Maximum for Any One Day
Average of Daily Values
for 30 Consecutive Days
Shall Not Exceed
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kg Ib kg Ib
kkg gross 1000 Ib gross kkg gross 1000 Ib gross
cane cane cane cane
BOD5_ No limitations No limitations
TSS 9.9 9.9 3.6 3.6
pH No limitations No limitations
The revised effluent limitations are less stringent than the original
ones, use gross rather than net cane as the production parameter, and
do not limit pH.
EPA developed the revised limitations from operating data at the
Honokaa and Hamakua factories where BPT is in place. The data came
from discharge monitoring reports submitted by the companies and
contained in compliance monitoring reports provided by the Hawaii
Department of Health. The Agency reviewed records from March through
December, 1978, for Honokaa, and July 1977 through December 1978 for
Hamakua. Monitoring data for May through December 1978, were
considered for Pepeekeo. The expanded ponds began operating in May.
ThU treatment plant effluent data for the three factories are
summarized below.
Honokaa
TSS (kg/kkg or lb/1000 Ib gross cane)
Maximum Day Monthly Average
March, 1978 2.0 1.56
April 7.37 2.96
May 1.61 0.74
June 2.83 0.98
July 2.01 1.53
August 1.21 0.77
September 4.95 2.29
October 2.40 1.57
November 4.00 2.85
December 8.07 5.01
Hamakua
July, 1977 1.04 0.64
August 10.8 2.8
September 0.74 0.51
October 1.4 0.71
November* 1.32 1.13
March, 1978 0.35 0.27
April 0.70 ' 0.54
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May 0.75 0.32
June 1.99 0.89
July 4.42 1.4
August 0.5 0.39
September 2.83 1.50
October 2.60 1.42
November 7.83 3.60
December 5.04 2.24
*Consists of a combination of 2 values for Nov., 1 for Dec. and 2 for Feb.;
these were the only values reported for these months.
Except for one monthly average and one daily maximum value, all of the
values for the two factories are less than the revised limitations.
The high monthly average resulted from one unusually high daily value
for which no explanation was reported.
pepeekeo
Rebuilt ponds treating the waste from this factory began operating on
April 26, 1978. Several months of effluent data for this system were
as" follows:
TSS (kg/kkg or lb/1000 Ib gross cane)
Maximum Day Monthly Average
May, 1978 3.85 2.18
June 12.45 5.08
July 9.60 6.17
August 39.16 18.52
September 27.52 12.56
October 35.78 15.64
November 55.69 20.58
December 35.83 19.81
The plant met the revised limitations during the month of May;
thereafter, the monthly average and maximum-day values increased and
are considerably higher than the revised guidelines. As indicated
previously, this system has not operated reliably,- however, plant
engineering personnel state that when properly operated and
maintained, the system achieves average TSS values of 7.15 Ib TSS per
1,000 Ib of net cane. This is equivalent to meeting the revised BPT
limitation of 3.6 Ib per 1,000 Ib gross cane because gross cane
typically is 50 percent debris or more. Under optimum operating
conditions, EPA Region IX, NEIC, and State of Hawaii personnel
determined that the system produces an effluent quality similar to
BPT.
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Gross Cane
The Agency has adopted gross cane rather than net cane as the
production parameter because it provides a more accurate method of
determining effluent loadings. Industry data show variations in the
wastage in the gross cane trucked to the factories. These variations
regularly occur because of differences in harvesting methods, terrain,
soil types, efficiency of cane burning, the use of ripeners and
defoliators prior to harvest, operator skill in using infield
equipment, and variations in rainfall. This latter point is
particularly significant. During periods of high rainfall, records
show that soil and debris may comprise as much as 70 percent of the
material delivered to the factory.
The use of gross cane as the production parameter takes these
conditions into account. Gross cane is weighed upon arrival at the
factory, and because it includes both debris and cane, it is more
representative than net cane (an estimated quantity) of variations in
the amounts of extraneous materials and the attendant waste load
imposed on the wastewater treatment facilities. The fluctuations in
waste load affect waste treatment plant performance and attendant
solids effluent levels. This is the rationale for the gross cane
parameter.
pH
The original limitation of pH to between 6 and 9 also was reviewed in
this study. Industry comments stressed the fact that the naturally
acidic nature of the Hilo-Hamakua Coast plantation soils was
responsible for low process wastewater pH values. A study by
consultants Sun, Low, Tom, and Hara showed strongly acidic soils in
the region of the Hilo-Hamakua Coast plantations, as shown in the
following table.
Plantation
Soil Type pH
Akaka 5.5
Hilo 4.3
Honokaa 6.0
Kaiwiki 4.9
Kukaiau 4.5
Ookala 5.0
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Paauhou 5.5
Available pH data for the process wastewaters from the Hilo-Hamakua
factories were very limited, but demonstrated the acidic nature of the
wastewaters. Information from Honokaa and Hamakua covered only a few
days of operation. Hamakua reported pH values as low as 5.2, at
Honokaa, pH values for five days of operation in 1975 were given as
follows:
Date pH Range
May 19 5.3 - 6.1
May 20 5.9-6.6
May 21 5.4-6.5
May 22 5.9-6.5
May 23 5.4-6.9
To modify the naturally occurring pH of the wastewaters would require
the addition of an alkaline material such as chemical lime; because of
the voluminous quantities of wastewaters involved, raising the pH to
the usually accepted minimum of 6 would require large amounts of
ctie'mical.
Consideration of these factors convinced the Agency that data were
insufficient to set a specific pH limitation. Therefore, the Agency
will not promulgate a pH limitation at this time.
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SECTION VIII
COSTS
Two of the Hilo-Hamakua Coast factories have BPT technology in-place
and in use; the third factory, which uses an alternate gravity pond
system, has all the necessary equipment to effect treatment.
EPA has identified the following additional costs for manpower and
basic equipment to insure adequate operation and maintenance of the
pond system.
Equipment Cost*
1. One D~3 Backhoe tractor to remove I
silt from ponds (at least one
is already in use) $43,704
Manpower
2. Two additional land containment
. *"* dredge operators $37,775
*January 1, 1979 dollars
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The costs developed for BPT are listed below and cover the following equipmen
secondary screens; clarifier; water pipes; pumping; polymer feed system;
vacuum filters; soil conveyance; and storage and trucks.
These figures represent costs for a plant
with in-place technology but no BPT waste treatment facilities.
This is the case for the one Hilo-Coast factory which has
substituted a ponding system for the BPT technology.
All costs have been adjusted to January 1, 1979 dollars.
Treatment Level Capital Costs*
BPT (1977)$1,874,000
Specific equipment costs are as follows:
Secondary screen** 129,600
Clarifier 432,500
Water pipes, pumping, etc. 19,400
Polymer feed system 79,500
Vacuum filters 416,700
Soil Conveyance and Storage 351,400
Trucks 445.000
1,874,100
* January 1, 1979 dollars
**Secondary screening or some substitute.
Operating Costs*
Secondary Screen Maintenance 2,650
Water Pump Maintenance 390
Polymer Feed System
- Operation and Maintenance 29,500
- Labor 29,900
Clarifier - O&M 5,800
Vacuum Filters
- Maintenance 11,600
- Labor 19,800
Soil Conveyance and Storage
- Maintenance 6,710
Trucks
- O&M 28,080
- Labor 205,840
Power 15.360
355,630
Land $0/yr - $31,200/yr.
*January 1, 1979 dollars
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