NC0004987_Supplemental Information_19890201

v- f
NPDES
�Uj' lemental Information
for
Marshall Steam Station
Revised 2189

A schematic flow diagram of water use, treatment
plished, and discharges indicating rates of flow provided,
rvindivial wa
for Marshall Steam Station is attached. recycling accom-
streams follows: A brief discussion oflindividual ewaste
1 Boiler Slowdown: The average total blowdown rate of 1
2,000 # hr. 3 and 4 boilers are supercritical and have nodb2 boilers is
steam flashes in a blowdown tank (1 & 2 boilers).
ay be
recovered for abllowdown. The
recycling. The condensate is discharged tosthe sfloor team mdrain.
Hydrazine is added to the boiler feedwater to remove dissolved
oxidizes to form nitrogen and water, and does not contaminate
lved oxygen, but
e the blowdown
2. Floor Drains: The wastes which enter the floor drains
are accumulated in the boiler and turbine room sumps.
nate from such sources as 1 at Plant Marshall
nt
equipment, (3) floor wash (1)oiler blowdowns ) The wastes origi-
nate
leakage. water, (4) equipment �cooling twater er eand e(5)
to the g All effluents from the floor drains are discharged
yard sumps and then pumped to the ash basin.
3. Chemical Cleanin of Boilers
Boilers #1 and #2 are chemically cleaned ever
and #4 are chemically cleaned every two y three years
boilers is 51,600 The capacity of�#lrand3#2
gallons each; boilers and #3 and #4 each have a card ity#
of 35,300 gallons.
cleaning boiler #1 oAp#2oximately 567,600 gallons of water is required for
cleaning
water per cleaning. Boilers #3 and #4 each require 317,700
The cleaning waste is transferred through gallonstempo-
rary piping to the permanent ash basin sluice line and on into t
he basin. Immediately
y prior to the beginning of a boiler chemical cleaning
pure. , additional blocks are added to the ash basin discharge struc-
ture- assures longer retention time of the chemical wastes f
proper treatment through dilution, neutralization
ion -exchange as documented in the Ash Basin Equivalency Demonstration or
(October 1976 Precipitation, and
A list of the chemicals and amounts requiredstoaclean
the
boilers at Plant Marshall follows:
Chemicals
Ammonium Hydroxide (260Be)
Hydrochloric Acid (31.5%)
Ammonium Carbonate
Soda Ash
Tri -Sodium Phosphate
Citric Acid
Sodium Bromate
Ammonium Bifluoride
Copper Complexer
4. Coal Pile Drains a Th
Amounts
Unit 1 or 2 —Unit 3 or 4
1,000 gal.
7,100 gal.
1,000 lbs.
4,400 lbs
400 lbs.
550 lbs.
2,150 lbs.
2,300 lbs.
4,800 gal.
3,000 lbs.
300 lbs.
1,500 lbs.
44.5 acres of watershedareal
al oayard at Plant Marshall covers approximately
in
sumps and is then pumped to therashhe cbasioal nard drains to the
MGD. This run-off is based on 40 inches . Taenaverage run-off is 0.66
run-off. P year with 50%
MS -PAGE 2

5. Ash Basin Overflow: The ash basin at Plant Marshall accommodates flows
from the yard drainfall run-off from
drainage sumps, ash removal lines and i
the basin watershed areas.
The average rainfall run-off flows are based on forty inches of rain per
year with fifty percent run-off
watershed area is 2 . The average run-off for the ash basin
.498 MGD. The average flow from the ash removal lines
is 1.728 MGD. The average flow from the
d
These individual flows give a total influent flow �togthe ubasin mps so1.121 f 5.35MGD.
MGD.
Due to the construction of the outfall structure, the effluent is essen-
tially equal to the influent flow (Refer to the attached schematic of the
water flow for further information of individual flows to the ash basin).
6. Oil —Storage Run -Off: Plant Marshall has two large above ground oil
storage tanks (each 500,000 gals.). These tanks are surrounded by a dirt
dike designed to contain the entire contents of the tanks in the event of
an accidental rupture. In addition to this precaution, an oil trap tank
has been installed to collect any spilled oil before the run-off reaches
the lake.
All oil storage facilities are presently covered under the Spill Preven-
tion Control and Countermeasure Plans.
7. Intake Screen Backwash: The intake screens are backwashed when necessary
at the rate of 300 GPM for 5 minutes each. There are 16 screens, so the
maximum volume of water used for backwash is 0.024 MGD when backwash
occurs. The screens (10' x 401) are stationar t
ype arefor
cleaning. The solid waste removed from the screens isneitherremoved hauled away
and buried in a land fill or taken to the ash basin, depending upon the
nature of the material.
8. Water Treatment Waste: The water treatment wastes at Marshall Steam
Station are made up of: (a) sedimentat+ion
demineralizer regeneration wastes. (b) filter backwash and (c)
Sedimentation is composed of solids that were present in the intake water
and aluminum hydroxide precipitate formed in the reactor as a result of
adding aluminum sulfate and sodium hydroxide to the service water for
clarification purposes. Approximately 8,000 GPD of sedimentation wastes
are discharged to the floor drains.
Filter backwash consists of approximately 7,000 GPD from the water clari-
fication system, 500 GPD from the demineralizer carbon filter and 1500 GPD
from the Powdex unit (3 and 4 Boiler condensate polishing system). This
backwash is discharged to the•floor drains.
The station is equipped with two sets of demineralizers. Each set con-
sists of two mixed bed cells. Each cell has a capacity of 225 GPM.
Normally, only one cell per set of demineralizers is operated at any one
time. The station experiences 3.3 regenerationsper week. On _
tion requires 36 gal. 6608e sulfuric acid and 126 gal. 5 % sodiums ydro-
xide. An average of 15,000 gal. of water are used per regeneration. The
MS -PAGE 3

dilute acid and dilute caustic are mixed in a common discharge for
neutralization purposes before being discharged to the floor drains.
The floor drains discharge to the yard drainage sumps then are pumped to
the ash basin.
9. Effluents from Air Pollution Control Devices: Electrostatic precipitator
are used at Marshall Steam Station to remove fly ash from the boiler s
gases. Typically, ash is removed in a dr form.
In
failure or during a boiler chemical cleaning, servicethe waterSisousedutoment
sluice the ash to the ash basin. Based on a yearly average, this flow
would be "0.173 MGD.
10. Sanitar Wastes: Plant Marshall utilizes a
waste. The average effluent is 0.011 MGD. This aflow ge liistdischarged for its atotthe
ash basin via the yard drain sump.
11. Condenser Conlin Water: A17 condenser tubes at Plant Marshall are
cleaned using an Amertap mechanical device. No chemicals are used for
this purpose.
Units 1 and 2 are each equipped with 2 condenser cooling water (CCW)
PUMPS. Units 3 and 4 are equipped with 3 CCW pumps each. The capacities
of these pumps are listed below.
CONDENSER COOLING WATER PUMP CAPACITY
Unit No. 1 -Pum GPM
s--�� 2 -Pump GPM 3 -Pum❑ GPM
1 90,000
2 90,000 130,000 ------
3 110,000 130,000 ------
4 110,000 190,000 260,000
190,000 260,000
CCW pumps are operated as follows on 1 & 2 units:
a. One pump operation:
1. When operating at less than full load and inlet water tempera-
ture is less than approximately 58°F.
b• Two pump operation:
1• When operating at full load and temperatures are above approxi-
mately 58°F.
CCW pumps are operated as follows on 3 & 4 units:
a. One pump operation:
1. One pump operation may be used under start-up and low load
conditions. Also during nonoperating conditions to provide
service water.
MS -PAGE 4

b. Two pump operation:
I. Normal operating condition.
C. Three pump operation:
L Conditions seldom necessitate the operation of three pumps.
MS -PAGE 5

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MS -PAGE 6 �''
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MS -PAGE 6 �''
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LEGEND
Plant Marshall Schematic
MS -PAGE 7
Flow Stream
1•
Av Dail Flow, MGD*
2.
Coal Pile and Yard Rainfall Run-off
Ash Basin Watershed Rainfall
0.084
Run-off
2.498
A.
Plant Intake
B-
Intake Screen Backwash
767.3
C.
Condenser Cooling Water
Intermittent
D.
Treated Water Makeup
764.3
E.
F.
Service Water for Miscellaneous Cooling0.582
Fly Ash Sluice Water
0.669
G.
Bottom Ash Sluice Water
Intermittent
H.
I•
Domestic Wastewater Treatment
1.728
J.
Condensate Feedwater System
0.011
K-
Miscellaneous Equipment Cooling
0.125
L.
Evaporative Losses, Soot Blowing
Miscellaneous Cooling Water
0.446
0.119
M.
N.
Boiler Chemical Cleaning Wastes
1.115
Boiler Blowdown
Intermittent
0.
Water Treatment Wastes
0.006
P•
Q.
Floor Drains and Sumps
Yard
0.0003
Drainage Sumps
1.145
001.
002.
Condenser Cooling Water Discharge
1.121
Ash Basin Discharge
764.3
5.35
*Flows are extrapolated beyond the scope of
in this table and throughout this
significant figures
narrative
variations in flow capacities.
to account for
MS -PAGE 7

Marshall
List of Hazardous Substances (Section 311)
Pollutant
Aluminum sulfate (Alum)
Ammonium acetate
Ammonium bicarbonate
Ammonium chloride
Ammonium hydroxide
Ammonium oxalate
Benzoic acid
Chlorine
Cupric sulfate
Ferrous ammonium sulfate
Formaldehyde
Hydrochloric acid
Phosphoric acid
Potassium chromate
Potassium hydroxide
Potassium permanganate
Silver nitrate
Sodium arsenite
Sodium bisulfite
Sodium hydroxide
Sulfuric acid (660Be)
Sodium phosphate (tribasic)
Uranyl acetate
Zinc acetate
Zinc sulfate
Acetic Acid (glacial)
Acetone
Calcium Hypochlorite
Ferric Chloride
Nitric Acid
Formic Acid
Ethylene Dichloride
uantit *
Source
5000 gal.
2 lbs
Water treatment
5 lbs.
Lab
1 lb.
„
„
330 gal.
„
1 lb.
„
120 gm.
„
1800 lbs.
2 lbs.
Water treatment
1 lb.
Lab
2 gal.
It
If
17.5 liters
5 gal.
�
1 lb.
„
33 lbs.
if
1 lb.
„
4 oz.
„
1 lb.
„
9 lbs.
„
10,000 gal,
Demineralizer
5000gal .
11 regenerate
4400 lbs.
Cleaning
1 lb.
Lab
4 oz.
„
4 oz.
„
25 liters
Lab
8 liters
11
26 lbs.
If
1 lb.
„
12.5 liters
1 gal.
If
1 pint
„
* Values represent maximum quantities onsite and do not necessarily ref
lec 4 -
quantities discharged. Treatment of these and other chemical substances"not
identified is achieved by the ash basin. Refer to Item 3 of "NPDES Supple-
mental Information" for a list of chemicals and amounts used for boilerp
cleaning.
MS -PAGE 9