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A WATKR QUALITY i'.TUDY
OF THE
PIGCATAWAY CREEK WATERSHED
August 1968
RegionaK enter ior Hn\ironment
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TABLE OF CONTENTS
Page
LIST OF TABLES iii
i,r,".T OR FinunKr, iv
ChAPTL'H
I. PRfiFACK I - 1
II. INTRODUCTION II - .1
A. Purpose and. Gcope II - 1
B. Authority II - 2
0. Acknowledgments TI - M
III. ;"UMMAHY AMI) RECOMMENDATIONS Til - 1
IV. DESCRIPTION OF AREA, WATER RESOURCES, AMD
WATER QUALITY STANDARDS IV - 1
A. General IV - 1
B. Water and band Related Resources IV - 3
C. Water Quality Standards and
Implementation Plan IV - 5
1. Water Uses IV - 5
2. Water Quality Standards ..... IV - 6
V. WASTI'WATKR TREATMENT FACILITIES V - 1
A. Andrews Air Force Base wastevater
Treatment Facilities V - 1
B. Piscataway Creek Wastewater
Treatment Facility V - 1
C. Other Discharp.es V - 6
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TABLE OF CONTENTS (Continued)
I CHAPTER Page
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VT. EXISTING WATER QUALITY VI - 1
A. Potomac River near Piscataway Creek VI - I
1. Water Quality Monitoring Programs VI - 1
2. Water Quality in the Upper Potomac
Estuary near Piscataway Creek VI - 1
B. Upper Piscataway Area Watershed VI - 5
C. Piscataway Creek Embayment VI - ^
1. Survey of July 11, 1968 VI - 9
2. Investigation of August 6, 1968 VI - 13
3. Intensive Surveys of August lU-16,
1968 VI - Ih
k. Investigation of August 23, 1968 VI - 26
VII. CORRECTIVE MEASURES VII - 1
A. Existinr Wastewater Treatment Facilities .... VII - 1
B. Existing Temporary Discharge Location of
the Piscataway Wastewater Treatment Plant . . . VII - 2
C. Expansion of the Piscataway Wastewater
Treatment Facility and Potomac
| Interceptor VII - '4
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Number
V-3
V_;>
VJ-1
VI -2
VI -3
VI -k
VI -5
vi -6
VI-T
vi -8
VI -9
LIST OF TABLES
Piscataway Wastewater Treatment Data,
January June 196B
Wastewater Oischarge, Piscataway Creek
Water Quality Data - Potomac Estuary
Monthly Summaries of BOD and DO Data,
Meetinghouse Hranch STP, Piscataway
Creek .
Monthly Summaries of BOD and DO Data,
Payne Branch STP, Andrews AFB,
Piscataway Wastewater Treatment Plant
Data, July 11, 1968, Chesapeake Field
Piscataway Creek Survey, July 11, 19o6,
Piccataway Creek Survey, August lh, 1?60,
Chesapeake Field Station
Piscataway Creek Survey, August 15, 1968,
Chesapeake Field Station
Piscataway Creek Survey, August l6, 1962,
Chesapeake ^ield Station
Wastewater Data - Piscataway Wastewater
Treatment Plant, August 14, 1968
iii
Page
V - It
V-3
VI - 3
VI - 6
VI 7 >
VI - 10
VI - 11
VI - \rj
VJ - 17
VT - 18
VI - 20
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LIST OF FIGURES
Number
I V-l General Iioention Mnp - Pntomnc R1v*>r,
V-l Schematic Diagram of Piscataway Waste-
VI -1 BOD, DO and Temperature, Potomac River
near Piscataway Creek
VI -2 Piscataway Creek Sampling Stations,
Chesapeake Field Station .........
Vl-3 Piscataway Creek Survey July 11, 1968 . . . ,
VI ^ Piscataway Creek Survey Aupust iH 1968 .
VI 6 Piscataway Creek Survey August 16 1966
VII-1 Wastewater Flow Patterns, Piscataway
Embayment . ........ . . ..
iv
Page
. . . -IV - :'
. . . V - 3
... VI - ?
... vi - a
. . . VI - 1?
VI - 21
VT 22
VT - 23
, . . VII - 3
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CHAPTER I
Th'1 Wan'i i nrlon , 0. f. , metrop'>1 i f.'in compl^/ i :> < r/tpi>:]'/
crowing ar^a, cnau^inp; not only the character of trv 1-mu use of
the upper Potomac Fstuarv Drainage Basin, hut also nlacinrr inercas-
i: ;T demands unon the water resources of the Fiver and it..s T,'s tuary .
Since 1900, the population of the metropolitan arfja nas frown from
about /'\100 ,00(j to the present estimated por-ulatior of q^proxinatel
:\900,nr,o.
f'irht najor municipal vastewater treatnert ^aci 1 it i-'.o 'iip-
charrR to the Potomac Estuary. The tr^r-tea disch--,r~p':- rnvr* n bio-
chemical oxygen demand (EOD) of 10'J,000 noimos oer :iay, equivsiJont
to the untreated sewage from bOO,000 peonle. Thi:-, louain-"1" ir, ,v!;out
:jix tires the natural capacity of tiie Estuary to as^imi] ate oxygen
acnandin/'- wastes arid maintain a dissolved oxypen (P-'"1) averapic of
^ivc r-,j 1 lifrnrro per .liter (mg/l).
'".16 facility at hlue Plains discharges direct \j into t.ie
'"otomac Hiver aiui is tne larpest, servinr the District of Colurildfi
and 1'irfie areas ir r'ontp;omery and Prince Ceor^es rour.ties, Marylana.
Thr remaining seven discharges are to e^baynents of the rotomnc
Kstunry. The relative advantages of conveying ti'eate'* w-istpwnter
cirectly into t.K- T'otomac Kstuary instead of into < e ST'?,,li eiji.-.'iy-
";er,t3 hrd not been previously investigated.
In recent months, public interest ir; tiie onerntinr' an; ^ff^c
of thr- r'isratavny '//astewater Treatment Plant on lJLs^ato*'iy Creel.
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_ water quality caused considerable attention to br riven to this area.
The problem is twofold: first, the limited assimilative capacity of
H tlun rnmill pmbaymont and, second, provision of stut.ahlr- "fai 1 ~r,;ifp"
m'.v/i;ini.';mn and operating procedures in the ivauLev//iL'}f Ln;utmenL
1'aci.litieG to eliminate discharge of untreated sr-wa/'e.
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II - 1
CHAPTER II
INTRODUCTION
I ^ Purpose and Scope;
As part of the Chesapeake Bay-Susquehanna River Basins Project,
I the Chesapeake Field Station (CFS), Middle Atlantic Region, Federal
Water Pollution Control Administration (FWPCA) has undertaken a com-
prehensive water quality management study of the Potomac IMver Basin.
Important phases of this study are determination of the effects of
wastewater discharges on water quality in the Potomac r.stuary and
recommendation of a program to achieve tne approver; water quality
standards for this interstate river.
In recent months there has been considerable oublic interest
in the operation of the Piscataway Wastewater Treatment Plant (PWTP)
of the Washington Suburban Sanitary Commission (WSBC) and the effect
| of plant effluent on the water quality of Piscataway Creek. A series
M of field surveys was conducted by CFS on the efficiency of the PWTP
and on water quality in Piscataway Creek.
This report contains the findings of the CFG studies to date.
The purposes of this report are:
|| 1. To provide information on:
a. Efficiency of PWTP
b. Effects of the discharge on the water quality in
Piscataway Creek and the Potomac River
c. General operation of the PWTP
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2. To investigate and recommend alternative locations for
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the effluent discharge point from the PWTP.
AJ though the acope of this report is prlmaril.v Limit.od to
the Piscataway Creek and the adjacent reaches of the Potomac K
other embayments in the area were investigated in order to compare
the Piscataway results with similar embayments including three not
receiving treated water discharges. In the future, the r;ipiu growth
of tiif area will require construction of additional wastewater treat-
ment facilities in the lower embayments, such as fattawornan Creek,
and may result in similar problems in this .and other embayments of
the Potoma.c Estuary.
E. Authority
This survey was conducted and the report prepared under the
provisions of the Federal Water Pollution Control Act as amended (13
U.fj.C. ^66 et seq_.) which directs the Secretary of the Interior to
prepare or develop programs for eliminating or reducing the pollution
_ of interstate waters and tributaries thereof and improving the sani-
tary condition of surface and underground waters, in cooperation with
State water pollution control agencies and witn the municipalities
and industries involved.
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C. Acknowle laments
The assistance and the cooperation of the Fashington Suburban
Sanitary Commission, Maryland State Department of Health (MSDII),
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Maryland Department of Water Resources (MDWP), and the Prince Georges
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County Cheverly Laboratory, enabled, the CPU to collect, assemble, and
evaluate the necessary data in a mucn shorter time than vmxilri otherwise
liave been required.
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'III - 1
CHAPTER III
SUMMARY AND RECOMMENDATIONS
Intensive field investigations, sampling surveys, and data
1 1 analyses have been conducted to determine the conditions in the
!«| Piscataway Creek and adjacent water by CFS, including the operations
of the Piscataway Wastewater Treatment Plant of WSSC. A summary of
the findings of these investigations, surveys, and analyses follows:
1. The Piscataway Creek Watershed, which is a Sub-Basin of
B the lower Potomac River below Washington, D. C. , has a
m drainage area of about 80 square miles.
2. The Piscataway Basin is rapidly being developed into
suburban residential areas with no major industrial
development in the area. Andrews Air Force Base is
j§ located in the headwaters of the Basin.
^ 3. The waters of the Piscataway Basin, including the embay -
ment , are used for commercial and sport fishing. In
the lower portion of the embayment near the Potomac
Estuary there is a marina and a national park.
P k. There are six municipal wastewater treatment facilities
in the Piscataway Basin discharging, after secondary
treatment, about 780 pounds of 5-day BOD into the waters
of the Basin.
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5. The Piscataway Wastevater Treatment Plant, which also
serves parts of Prince Georges County outside of the
, eontri haters fit 'out HO percent of I\M- ilomr:;!, 1 c
wastewater loading. The current population of the
service area is about 110,000, with a projected population
of over 600,000.
_
6. The Piscataway Wastewater Treatment Plant has a nominal
design capacity of 5-0 million gallons per day (mgd).
This facility was placed in operation in late 1967 and
ft has a temporary discharge to the Piscataway embayment.
« 7. Since the Piscataway plant was placed into operation,
the following have occurred.
a. Flow exceeded nominal design capacity. For example,
j in June 1968 , the average flow to the plant was
6.5U mgd.
b. Untreated sewage has been by -passed to the Piscataway
* embayment, resulting in numerous complaints by local
ft residents.
c. Operational difficulties occurred at the treatment
; facility, resulting from power failures and inexperienced
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! personnel .
8. Evidence of water quality degradation has been observed
in the embayment near the pumping station and near the
wastewater outfall. Chemical analysis of the water also
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III - 3
indicates high nutrient (phosphorus and nitrogen)
concentration in these two areas.
9. Due to the very limited fresh water inflow and exceaaivi*
weed growth, the water movement is restricted and thus
reduces the overall effect of the periodic tidal flushing
of the embayment in the vicinity of the pumping station
I and the temporary outfall.
10. During low tide, the water depth in the embayment near
the discharge point is less than a foot. The effluent
from the wastewater plant flows within 100 feet of the
shoreline of a residential area downstream from the
I outfall.
m 11. In the lower Piscataway embayment near the Potomac Estu-
ary and in the Estuary itself, extensive algal blooms
have been occurring in recent years, apparently as a
result of the wastewater discharges from the Washington
| metropolitan area. The dissolved oxygen in the upper
M Potomac Estuary below Washington often falls below 3.0
mg/1 in the summer months.
After investigations following a series of complaints by
residents in the area adjacent to the wastewater treatment plant,
the Maryland State Department of Health directed that WSSC take
the following actions:
1. Limit the flow into the plant to an average daily flow
I of 5.0 mgd;
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III - k
2. Install an alarm system which would be activated during
periods of by-passing of flows; and
3. Upgrade the general operating conditions of the plant,
including training personnel.
~ WSSC has complied with this directive.
Since mid-July of 1968, analyses of the efficiency of the
wastewater treatment plant by WSSC, MSDH, FWPCA's advanced waste
treatment group, and CFS indicate that the efficiency is of very
good quality.
* As part of the water quality management program for the
fl Potomac River, including Piscataway Creek, tne following specific
recommendations are presented for the WSSC facility:
I 1. As originally proposed by WSSC and approved by Maryland
State Department of Health and FWPCA, an outfall should be constructed
to tne main channel of the Potomac Estuary.
M 2. An investigation should be made and appropriate action
taken by WSSC to eliminate by-passing of untreated sewage to the
Piscataway embayment.
3. To provide for better dispersion of the wastewater in
marshy areas of the embayment, pending completion of the Potomac
I outfall, a channel should be excavated or temporary pipeline laid
to convey the final effluent out to the southerly stream channel.
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III - 5
As guidelines for long-range planning, the following general
recommendations have been developed as a result of the Piscataway
investigation and the previous studies of the entire Potomac K.ntunry
by CFS:
1. No new discharges of wastewater to the Estuary or to its
embayments, temporary or permanent, should be approved
| until an engineering study has been made on the assimi-
A lative capacity of the receiving water and a plan developed
to eliminate discharge of untreated wastes.
2. Inspections and efficiency studies should be made on-all
treatment facilities at least four times a year to insure
| high quality operation and to provide an opportunity for
discussion of any operational problems with the plant
i personnel.
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IV - 1
CHAPTER IV
DESCRIPTION OF AREA, WATER RESOURCES,
AND WATER QUALITY STANDARDS
A. General
tt The Piscataway Creek Watershed has a drainage area of 81.5
square miles and is located about 12 miles southeast of the center
of Washington, D. C. (see Figure IV-l). The Creek, whicn flows in
a westerly direction, enters the upper Potomac Estuary about 98
miles upstream from the Chesapeake Bay.
Since it is located in the Washington metropolitan area, the
Watershed is rapidly being developed into a suburban residential area.
Housing for employees of Andrews Air Force Base, which is located
partly in the upper portion of the Piscataway Sub-Basin, has also
added to the urban development of the Basin.
There are no major industries in the Watershed. The only
industrial discharges are from sand and gravel operations in the
non-tidal portions of the Watershed.
Except for the embayment segment of Piscataway Creek, the
Stream is small, sluggish, and, in the headwaters, the stream flow
is intermittent. The maximum, mean, and minimum flows from a stream
; gaging station established near Piscataway, Maryland, in 1965, were
328, 19.7, and 0.0 cubic feet per second (cfs), respectively. Using
the longer term records of Henson Creek, which has an average yield
of 1.10 cfs per square mile, the average annual flow from the entire
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WASHINGTON D.C.
Ptntogon S.T.Pi
Arlington S .T, P.
Dist. of Columbia
at«r Pollution Control /Mant
Altxandria S.T. P.
Fa i rfa x - Wt »*gat« S .T. P.
te Hunting Cr. S.T.P.
ut Cr. S.T. P.
'Piscataway Cr. S.T. P.
GENERAL LOCATION MAP
POTOMAC RIVER - WASHINGTON METROPOLITAN AREA
FIGURE
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IV - 3
Piscataway Creek Watershed is estimated to be about 90 cfs. The
upper part of the embayment is a swamp with abundant growths of
submerged and emergent aquatic plants. Tentative identification of
the noted aqua!,ic growths _ndicates that the majority of the emergent
plants are reed grass, Phyragmites and Pontederia cordata. The sub-
merged growths appear to be mostly coontails, Cereatophyllerm. The
center and lower embayment is about four to six feet deep and has
I
little or no submerged and emergent plants.
B. Water and Land Related Resources
_ The waters of Piscataway Creek are used for both tidal and
non-tidal fishing. According to the Annotated Code of Maryland, the
waters of Piscataway Creek above Maryland Route 22k are considered
non-tidal.
Although sport fishing is not widely practiced due to the
limited access to embayment waters, local residents have made catches
of catfish, carp, perch, and rockfish in Piscataway Creek. During a
CFS sampling survey, a local resident who has fished the Piscataway
for the past 20 years stated that he had not noticed any great change
in the fish population. He did indicate that there had been an
increase in commercial fishing for carp and catfish in the swampy
area of the embayment in recent years. Also, during many of the
surveys, numerous species of fish were observed, especially in the
marshy area of the embayment.
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During the spring spawning period, herring are netted from
the waters of Piscataway Creek. Larger catches are obtained near
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Indian Head Highway and other shallow portions of the upper erabayment .
I According to a game warden of the Maryland Department of Game and
Inland Fish, the 1968 herring run in Piscataway Creek was considered
to have been good.
_ After long periods of hot, dry weather, crabs are often seen
in the Piscataway Creek embayment. However, the crabs observed are
It too small in size and in number to have any sport or commercial
significance.
There is a marina on the northern shore of Piscataway Creek
_ near the confluence with the Potomac River. The marina provides
slips for approximately ^50 boats, 30 of which are covered.
Also on the northern shore of Piscataway Creek embayment and
continuing along the shoreline of the Potomac River is the Fort tfash-
ington National Park. Historically, since the early iSOO's this Fort
had been the key defense position for the City of Washington, D. C.
B Since World War II, however, the Fort has been made into a National
Park. This Park, which is operated by the U. S. National Park Service,
had 413,000 visitors in 1967.
The remaining portion of the embayment, including the southern
shore, has been developed for residential use and includes several
small, private recreational areas and marinas.
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IV - 5
C. Water Quality Standards and Implementation Plan
, *
m In 1967, the State of Maryland
". . .in order to provide for the enhancement of
I the water quality where such quality hus deteri-
orated or is deteriorating, for the conservation
| of water quality where such quality is good or
M satisfactory, and for the protection of lawful and
reasonable uses ..."
established both general and specific water quality standards for
both inter and intrastate waters. A plan for implementation and_
| enforcement of the water quality standards for all of Maryland's
« waters was also established. The standards and the implementation
plan for the interstate waters were approved and adopted by the
B U. S. Department of the Interior in August 196?.
1. Water Uses
The uses of waters of the Potomac Estuary were grouped into
_ six categories as follows:
"I - Shellfish harvesting
"II _ Public or municipal water supply
"III - Water contact recreation
"IV _ Propagation of fish and other aquatic life and
m wildlife
Water Resources Regulation h.Q, General Water Quality Criteria and
Specific Water Quality Standards for all Maryland Waters, Water
Resources Commission and Department of Water Resources, Maryland
State Office Building, Annapolis, Maryland 21^01.
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"V - Agricultural water supply
"VI - Industrial water supply"
For each of the water uses categories, bacteriolopii'iil, dinaolveti
oxygen, pH, and temperature standards were specified. The desig-
nated uses of applicable water zones of the Piscataway Creek water-
shed are presented below:
Waste of Water Zone
Piscataway Creek and Tributaries
(Headwaters to Md. Rt. 22k)
Piscataway Creek and Tributaries
of Potomac River
(From Md. Rt. 2'A to Mouth)
Water Use to be Protected
III, IV, V, VI
III, IV
2. Water Quality Standards
Dissolved Oxygen (DO) is the parameter most indicative of
water quality in a free-flowing stream or estuary of this
type. Wastewater treatment requirements and/or flow regu-
lation needs were determined using a mean monthly DO level
of 5.0 mg/1 with a minimum level of U.O mg/1. This is the
approved standard for the waters of the Piscataway Creek in
the study area. (See Water Resources Regulation h.ti of the
State of Maryland for other specific bacteriological,
temperature, and pH standards.)
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CHAPTER V
WASTEWATER TREATMENT FACILITIES
I
In the Piscataway Creek Basin there are seven wastewater
discharges. One of the discharges is mineral, and the remaining
six are organic in nature.
A.. Andrews APE Wastewater Treatment Facilities
Andrews Air Force Base has two wastewater discharges in the
Basin. Plant Number 1, which discharges into Meetinghouse Branch of
Piscataway Creek about 13 miles upstream from the Potomac, has an
average flow of 0.65 mgd with a biochemical oxygen demand (BOD) load-
ing to the River of 90 pounds per day. The Number h plant, which has
an average flow of 0.06 ragd and BOD loading after treatment of 10
pounds per day, discharges into Paynes Branch of Piscataway Creek
about 13 miles upstream from the Potomac River.
Both facilities consist of Imhoff tanks, trickling filters,
secondary sedimentation, and chlorination. BOD removal efficiency
of 89 percent and 83 percent for plants "los. 1 and hy respectively,
is obtained. A summary of the water quality below the two discharges
| is fiven in Chapter VI.
I E' Piscataway Creek Wastewater Treatment Facility
The treatment facility was placed in operation in late 196?
and has a design capacity of 5.0 mn;d at a 5-day BOD removal efficiency
of 90 percent. Flows above this capacity can be treated at a reduced
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BOD removal efficiency. Provisions have been made on the site to
expand plant capacity to 30 mgd.
Tue sev.'ip'" is broupht lo the facility by two forr° mnnis,
one from the Henson (.'reek area nnd the other serving the uu.jarent
Piscataway Creek area. The plant provides activated sludge treat-
ment with sluap;e digestion, conditioning and vacuum filtration. The
effluent is chlorinated and discharged into a partly lined channel
which flows into a marsh area of the enbayment. A schematic diagram
of tne plant is raven in Figure V-l. Tn an agreement recently sip/ie-;
with FWTC/i, the V.'SSC is to design and ouild a U.O rrr*d advanced waste-
water treatment (AWT) pilot plant consistinr of lime precipitation
and sr-dimentation, filtration, ana carbon adsorption.
The major factors influencing effective utiJ ization of the
"Piscataway Creek facility include operating problems, presence of a
bypass, location of tne temporary outfall, and hio;h flows to tne
nlant. In the first six months of the year, except for January,
there werp days miring which the average daily flows were from 6.0
to °.0 mp-d. As can be seen in Table V-l, the overape daily flows
for tne months of April, May, and June were above the nominal
desipn capacity of tne plant.
While the reported plant efficiencies in terns of BOD nnd
suspended solids removal are hiRh, tnese figures are misleading, since
the influent figures were not representative of the untreated sewage.
nevertheless, excluding the times when the averape flow was greater
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\PROPOSED OUTFALL
^TEMPORARY OUTFALL
HENSON-BROAD CREEK AREA
GRIT CHAMBER
SCHEMATIC OF PISCATAWAY WASTEWATER TREATMENT PLANT
FIGURE Z-l
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V -
_ than 5-0 tird , as ,o;ivcn in Table V-l, the plant is capable of provi'
ing 90 percent BOD removal.
Plan's for the Piscataway Wastewater Treatment Plant, as
originally approved by the Maryland State Department of Health,
provided for an effluent lime some three miles lon/r discharging the
treated wastes into the main channel of the potor»ic v;iver. Thr
plans and specifications as submitted were reviewed and approved for
a construction p;rant by FWPCA.
Wlien some difficulty developed in obtaining a rirht of way
for an outfall to the Potomac, WSSC submitted plans and specifica-
tions for a temporary outfall to discharge into tne head of the
Piscataway errbayraent in July 1967. This was approved by MSDK .
Operational problems occurrea in sludge handling, screen
cleaning equipment jammed, and pumpinp; stations were subject to
power failures. No emergency stand-by power was provideci in the
original design, nor was there any alarm system to indicate failure
of equipment in the system.
During the first six months of 196p., power failures and
_
operational problems resulted in the discharge or raw or partially
flj treated sewage into Piscataway Creek. The limited transport ar.u
assimilative capacity of the embayment obviously caused a degrada-
tion in its water quality far more than a similar accidental dis-
cnarpo would have caused in the Potomac River.
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V -
_ The discharge of untreated sewage and, to some extent, tne
overloading of the treatment plant suggest these three general needs
wnich should be studied to identify actions which snould ije taken lo
prevent water quality degradation in all embaymentt; of the Potomac
Estuary in the future:
] . More frequent surveillance of the wast water treatment
facility by the appropriate State and County health
agencies.
P. Incornoration into the design of the wastewater facility
a "fail-safe" warning or stand-by system which v,ri]l'
minimize uncontrolled discharges of untreated wastes.
3. Specialized engineering studies in the design and the
selection of discharge points for the wastewater
I
effluents. The study should also incorporate the
affects of possible discharges.
I Tne latter of the three needs i? the primary area of concern
in the surveys which were subsequently conducted by CF'".
C. Other Discharges
The remaining organic wastewater loadings into Piscataway
Creek, about seven percent of the total, come from throe sources,
Cheltenham Boys Village, II. S. T-Iaval Communications Station, and
the Country Club Cleaners. These three, which have a total HOI)
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V - 7
I
loading to the Piscataway Creek of 50 pounds per day, will probably
be connected to the WSSC system in the near future as the sewer
system is expanded. In Table V-2 is presented a complete listing of
| wastewater discharges into the Piscataway Creek Watershed.
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VI - 1
CHAPTP1R VI
EXISTING WATER QUALITY
A. Potomac^River Near1 Pia cat away Creek
1. Water Quality Monitoring Programs
Water quality in the Potomac River in the Washington, D. C.,
area has been monitored since the early 1930's by the Department of
Sanitary Engineering, District of Columbia Government. Since the late
J-950's, originally the U. S, Public Health Service and presently the
Federal Water Pollution Control Administration has also conducted
numerous water quality surveys in the upper Potonac Estuary. An
automatic water quality monitor at Fort Washington was added to the
existing system in the Potomac Estuary in 196U.
2. Water Quality in the Upper Potomac Estuary Near Piscataway
Creek
The water quality in the Upper Potomac Estuary near Piscata-
way Creek is greatly affected by the wastewater discharges, as shown
in Figure VI-1. Approximately 100,000 pounds of 5-day BOD and
136,000 pounds of suspended solids are discharged into the upper
Estuary above Piscatawey Creek each day.
As can be seen in Fipure VT-1, BOD loading during the low
flow months of June, July, August, and September, depresses the DO
in the main channel of the Potomac Estuary below the State Standard
of 5.0 mg/1. BOD data from the 1968 survey, as given in Table VI-1,
exhibit similar effects on water quality.
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VI - 3
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VI - h
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A nutrient load is also associated with the large BOD and
I suspended solids loadings in all the wastewater discharges in the
upper Potomac Estuary. Based upon current wastewater volumes, ap-
proximately 66,000 pounds per day of total phosphorus as PO, and
50,000 pounds per day of total Kjeldahl nitrogen (TKN) as nitrogen
are discharged into the estuary.
During the past five years, extensive algal blooms have been
observed in the upper Potomac Estuary. The blooms, consisting
principally of Anacystis sp., Oscillator!a sp., and Chlamydomonas sp.
occur in areas which are high in nutrient content.
As presented in Table VI-1, the nutrient concentrations for
the Potomac Estuary for 1968 indicate a high concentration of phos-
phorus and nitrogen near the confluence with Piscataway Creek. For
11 the months of May, June, July, and August, the average concentration
of PO^, TKN, and NOg-NO were 1.06, 1.89, and 0.99, respectively.
Associated with these high nutrient concentrations were high
I*
chlorophyll levels in the Potomac Estuary near Piscataway Creek.
As can be seen in Table VI-1, the chlorophyll levels for the latter
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part of July and for August were above 50 yg/1. During August, there
was an extensive algal bloom in the entire upper Potomac Estuary.
I*
Chlorophyll is a gross measure of algal concentrations or
, "standing crop." A chlorophyll level of 50 yg/1 is considered
to be a "bloom."
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VI - 5
1
B. Upper Piscataway Area Watershed
Water quality in the upper Piscataway Creek has been monitored
by personnel of Andrews Air Force Base above and below the discharge
I points of their waste treatment plants since 196?. A summary of tue
_ weekly sampling program is presented in Tables VI-2 and VI-3 for the
Meetinghouse and Paynes Branch facilities, respectively.
As can be seen in these Tables, the effects of the wastewater
discharges on DO and BOD in Paynes and Meetinghouse Branches are
insignificant. The BOD below the two discharges is usually less
_ than 0.5 nig/1 larger than above the facilities, with the DO essen-
' tially the same above and below the discharges.
The water quality standard for DO, which is 5.0 mg/1 monthly
average, was met in Paynes Branch except for October of 1967. How-
ever, the DO above the discharge point at the same time was also
below 5.0 mg/1. In general, the water quality in the headwaters of
Piscataway Creek appear to meet the approved quality standards.
I C. Piscataway Creek Bmbayment
« A series of stream and wastewater treatment plant surveys
was conducted by CFS in order to determine the effects of wastewater
discharges on water quality in the Piscataway Creek embayment,
especially those discharges in the Piscataway Basin and in the
i I Potomac Estuary, and including land runoff. Sampling stations in
_ the Piscataway Creek embayment are shown in Figure VI-2. The
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VI - 6
TABLE VI-2
MONTHLY SUMMARIES OF BOD AND DO DATA
Meetinghouse Branch STP
Piscataway Creek
800 Feet
Above Outfall
2 Miles
Below Outfall
Year
67
67
67
67
67
67
67
67
67
67
67
67
68
68
68
68
68
68
68
Month
January
February
March
April
May
June
July
August
September
October
November
December
January
February
March
April
May
June
July
BOD
(mg/1)
1.5
5.0
1.7
2.5
1.5
2.1*
2.1*
1.3
1.9
2.5
2.0
2.2
2.U
1.6
2.7
i*.o
3.1
3.0
DO
(mg/1)
10.3
9.5
10.2
9.1
8.6
7.3
7.3
6.U
6.6
6.7
8.3
10.4
11.9
8.6
8.5
7.0
6.9
6.0
BOD
(mg/1)
2.3
1*.6
2.5
1.6
0.8
1.7
1.7
1.6
1.5
1.9
2.3
2.8
U.2
2.1*
2.9
5.0
2.9
2.5
DO
(mg/1)
10.0
10.3
10.1
10.6
7.3
5". 3
5.3
6.8
5.6
5.9
8.0
9.7
10.6
7.6
7.3
7.2
6.0
6.2
Analysis made by Andrews AFB personnel four times per week.
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VI - 7
TABLE VI-3
MONTHLY SUMMARIES OF BOD AND DO DATA
Payne Branch STP
Andrews Air Force Base
Piscataway Creek
800 Feet
Above Outfall
2 Miles
Below Outfall
Year
61
61
61
61
61
61
61
61
61
61
61
61
68
68
68
68
68
68
68
Month
January
February
March
April
May
June
July
August
September
October
November
December
January
February
March
April
May
June
July
BOD
(mg/1)
2.9
3.2
1.0
0.6
1.2
1.3
1.8
1.6
2.3
2.9
2.1
1.9
1.5
2.4
1.9
2.0
3.9
1.9
3.2
DO
(mg/1)
6.5
8.9
9.6
7.2
7.0
6.3
6.3
6.3
5.3
4.9
6.1
8.1*
8.7
11.2
8.8
8.2
6.3
7.1*
6.0
BOD
(mg/1)
2.2
3.9
4.5
1.6
2.1
2.0
2.0
1.4
2.0
2.7
2.6
1.4
1.1*
2.8
2.7
2.6
2.0
3.3
3.3
DO
(mg/1)
6. it
10. 4
11.0
9*5
7.4
6.3
6.3
6.4
5.5
4.4
6.3
8.2
8.6
10.1
8.4
7.3
6.8
5.9
5.9
Analysis made by Andrews AFB personnel four times per week.
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FIGURE 31-2
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VI - 9
surveys were incorporated into the larger program of the upper
Potomac Estuary from the Washington, D. C., area to 301 Bridge near
»
Morgantown, Maryland.
1. Survey of July 11, 1968
Data from the embayment and waste treatment plant surveys
are presented in Tables VI-1* and VI-5, respectively. The survey was
conducted during high tide.
As can be seen in Figure VT-3, there was a pronounced algal
bloom in the embayment during the survey. The algal concentration
in the Potomac Estuary vas about one-half of that in the ^iscataway
embayment .
The phosphorus values in the vicinity of the waste treatment
facility were about twice those in the Potomac Estuary or in Piscata-
way Creek as it flowed into the embayment. The nitrite-nitrate
(lI00-NO ) concentrations decreased with distance from tne treatment
M
plant, suggesting that denitrifi cation was occurring. Since TMN
J data was not taken, no nitrogen balance was attempted.
_ The BOD in the embayment near the treatment facility was
only slightly higher than in the Potomac Estuary (Figure VI-3) .
However, the BOD of Piscataway Creek at Indian Head Highway was less
than 5-0 mg/1, suggesting that BOD in the embayment is coming from
both the Potomac Estuary and the PWTP.
*
The data from this survey will be presented in a separate report
by CFS.
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VI - 10
TABLE VI-i)
PISCATAWAY WASTEWATER TREATMENT PLANT DATA
July 11, 1968
Chesapeake Field rotation
Parameter
Average Flow (mgd)
Maximum Flow (mgd)
BOD (mg/1)
TKN as N (mg/1)
Nil as K (mg/1)
NO-NO as N (mg/1)
T. PO^ as PO^ (mg/1)
*
Influent
U. 20
5.00
91.50
10.50
6.90
1.79
9.65
#*
Effluent
it. 20
5.00
32.1|0
16.30
10.50
0.08
15.71
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Based on a three-hour composite, 9:00 a.m. to 12:00 noon, on
July 11, 1968, of the incoming wastewater from the Piscataway
I area only, and therefore is not a good measure of incoming
characteristics .
y, M
Based on a 2)4-hour composite, 8:00 a.m. on July 10, 1968, to
8:00 a.m. on July 11, 1968.
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VI - 11
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PISCATAWAY CREEK SURVEY
JULY 11,1968
Chtsopeakt Field Station
^
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LEGEND
MAIN STEM
TRIB NEARSTP
SAMPLING TIME-0955 to 1045
HIGH TIDE -0946
BOD
O
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MILES FROM POTOMAC RIVER
FIGURE 21-3
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VT - 13
At stations P-l, P-2, ana P-3 in the southerly channel,
coliform concentrations were the highest. The concentration of
fecal coliforms, which is an indicator of human wnHt.^, war, hirh^r
at stations P-l, P-2, P-5, and P-6 than at the remaining stations.
In the embayment and in the Potomac Estuary, DO concentra-
tions be]ow 5-0 mg/1 were observed. As presented in Figure VT-1,
a total of five stations had DO levels less than t-u: adopted standard:
fl The hif^h concentration in the middle of the embayment was probably
due to the oxypen production of the standing cron of alpae.
While sampling the Piscateway embayment, numerous ras bubbles
in the tributary near the wastewater nlant were observed near the
stations P-l and P-P by CFS personnel. fias bubbler; nmanatitir from
sltiRgisn writers in marsh areas are coironon and, therefore, no special
significance can be attached as to their causes.
During the survey, an analysis of trie influents and effluents
of the PWTP was made as given in Table VT-i(. Although the influent
B sajnyjlinp; point was not representative of &T1 the untreated wactc-
m water, the data inaicete that the facility was then producing a
5-day ROD removal efficiency of about 65 percent.
?. Investigation of Aup^ist 6, 1968
As a result of an odor complaint, an investigation
was made of the water quality conditions in the Piscataway Creek
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VI - l't
enbayrnent. I'uritic: a reconnaissance of tne udor war, detertod
However, in a visit to PWTP later the sane day, it was learned that
flt them hud Lc^n sorn
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VI - 20
TABLE VI-9
WASTEWATER DATA
Piscataway Wastewater Treatment Plant
August l'i, I960
Reduction
Parameter Influent
Flow (mgd) 5.2
#*
BOD (mR/1) 93.5
3. Solids (mg/l)
T. POj as PO^ (rr.fr /]) 11.0
TFJi as IJ (ing/l) 11.2
n"K_ as N (mg/l) 12.7
j
noo-JMOn as N (mg/l) 0.5
Effluent
5.2
17.5
e.o
6.6
9.6
7.7
1.2
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200
g
s
O
100
I
3.0
a. c\j
1.0
0
20
10
PISCATAWAY CREEK SURVEY
AUGUST 14,1968
Chuoptak* Field Station
oo r-
a a.
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200
a 100
g
3
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a
4.0
a. o
1.0
0
20
'0
PISCATAWAY CREEK SURVEY
AUGUST 15,1968
Ch«»ap«ok« Field Station
oo r-
a. a.
LEGEND
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PISCATAWAY CREEK SURVEY
AUGUST 16,1968
Ch«»ap«a)c« Field Station
TRIB NEARSTP
SAMPLING TIME-0930 to 1215
HIGH TIDE -0900
I 2
MILES FROM POTOMAC RIVER
FIGURE 21-6
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VI - 2k
higher concentrations, which were observed at low tide, are probably
#
_ the result of tidal flushing of the wastewater discharge.
The BOD «nd IX) determinations of the three surveys exhibit.
I similar characteristics in the nutrient data, as also given in
Figures vT-^i, VI-5, and VI-6. However, the concentrations near the
pumping stations near the manholes were not much different from the
stations on the main channel.
' In general, the BOD in the Potoinac Estuary near Piscataway
Creek was about 10 mg/1. The EOD in the Piscataway embayment wos
also about 10 mg/1, thus suggesting that BOD in Piscataway embayVient
is related more directly to BOD in the Potomac than to the Creek
itself.
Using a tidal height prism of 2.U feet and a surface area of
i
! 5.53 million square feet, it was determined that about 17,000 pounds
per day of BOD enter and leave the Piscataway embayment from the
Potomac Estuary. This compares to less than 1,000 rounds per day
cominr from wastewnter effluents and the fresh water flow into
Piscataway Creek.
Although the data required for determining exchange rates
are not currently available for Piscataway embayment, it can readily
be seen from the above calculations thft organic loading, including
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*
In later investigations it was determined that effluent
"hug" the southern shore, thus confirming the interpretation
of the August 16 data.
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VI -25
the nutrients in the middle and lower Pi scat away embayment , is con-
trolled primarily by the quality of the Potomac Estuary. Nevertne-
leus, it can nlrso bo seen in Figures VT-'t, VT-'j>, and VT-Ti t.hnt UK*
effluent from the Fiscataway Wastewater Treatment Plant dons affect
effluent and water quality in the embayment, especially in tnc small
| tributary on tne southern shore.
M CoHform concentrations of over 9,000 MPN/10U ml were observed
in the upper portions of the southerly and northerly channels. The
highest counts, over 2^,000, were detected in the southerly channel
near the manhole by the pumping station. As can be seen in Table
| VI-5, the highest fecal coliform counts are for the two uppermost
_ stations in the main or northerly channel. Urban runoff from rj
recent rainfall may have been the probable source cf tnese nifh fecal
I counts .
Results of the efficiency study of the wastewuter treatment
facility, as Riven in Table VI-1,', indicates that the effluent leaviru*
the plant is of very pood quality. The BOP and suspended soliJs were
Bl 17-5 and 0.0 mg/1, respectively, for the 2U-hour composite sample.
The influent to the plant appears to be very weak for a
domestic sewage. The incoming wastewater ranges from about TO to
120 mg/1 of ^-day BOD, with an average of about 95 rag/n . Similar
BOD concentrations for the influent were observed by MT>DIi and WS3
personnel.
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VI - 26
k. Investigation of Aupaist 23, 1968
A complete inspection of the Piscataway area wastewater
treatment plant find adjacent area wns made by CT?fi personnel on
Aurust 23, 1968. During the inspection of the plant, the followinr
were observed.
a. ',nhf plant was operating efficiently.
b. The effluent, whinh was beinp; monitored continuously
by FWPCA, indicated that BOD was between 10 and 20
mr/1, with the suspended solids concentrations rangin/r
from h to 17 mg/1.
c. An alarm system, which had been installed recently, ap-
peared to be working satisfactorily. .- lop of eacu
alarm activation is beir.r kept by WSSC personnel.
d. Gince the plant was placed into operation, no solids
from the digester have been wasted. Start-up seed was
beinr brought to the plant from the Laurel-Parkway
facility of WSSC to aid in establishing the proper
bacteriolop;ical cultures.
e. No evidence of recent by-passinfr or accidental spills
was observed.
f. A maintenance crew was filling a gully formed by the
effluent near the present terminal end of the discharge
interceptor. As a result of this fillinr operation, a
hip;h silt load was picked up by the effluent strea^.
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VT - 2?
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An inspection »t low tide was also made of the Calvcrt
Manor area which is downstream from ana adjacent to the WSHC
facility. The combination of low tide and the larpy quantities of
silt in the effluent clearly showed that effluent from the waste-
water plant was flowing along the shore, near the site of the original
I*
Lord Calvert p;rant. Under these conditions, the water is less
_ than one foot deep, and the only discernable flow was tne wastewater
* discharge.
B The "tagfunp" of the effluent by silt particle;; clearly
showed the course of the effluent. This confirms the reports of
local residents of Calvert Manor that an accident or malfunction at
the plant would readily be noticeable from the shoreline as, for
example, durinp the early August breakdown when the area near the
shoreline was reported to be an "open sewer" under low tidal
conditions.
#
This historical site is currently beinf restored by the Clapgett
family.
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VII - 1
CHAPTER VII
CORRECTIVE MEASURES
A. Kxiating Wustewater Treatment Facilities
As indicated in Chapter V, there are seven wastewater dis-
charges in the Piscataway Watershed discharging about 5.0 ragd with
a 5-day BOD loading of T80 pounds per day. All of the treatment
facilities are currently providing secondary treatment with a BOD
removal efficiency of 83 percent and greater.
Since August 1, 1968, as directed by the Maryland State
Department of Health, the following actions have been taken by V/6SC
at the PWTP,
1. The flow into the plant has been limited to average
daily flow of 5.0 mgd.
2. An alarm system has been intalled to indicate pumping
or other mechanical difficulties whicn could result in
by -pas sing untreated sewage.
3. General upgrading of plant operation.
The above actions by the Maryland State Department of Health
and WSSC are endorsed in this report.
A major deficiency at the existing plant appears to be failiire
to provide stand-by electric power. If a power failure occurs, the
incoming wastewater will be by-passed from a manhole near the plant's
pumping station serving the Piscataway area or from the Broad Creek
pumping station for the remaining service area.
f
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VT! - °
To eliminate or significantly reduce the incidence of over-
flows which have occurred in both service areas, it is recommended
that stand-by power be provided at all pumping stations. As a pre-
cautionary measure, in case of dual failure, a plan for diverting or
storing of the wastewater should be developed to prevent diecharge
of untreated sewape.
B. Existing Temporary Discharge Location of the Piscataway wastewater
Treatment Plant
As indicated in the previous chapter and as shown in Figure
VII-1, the existing discharge location results in a wastewater flow
pattern in the Piscataway embayment which flows alon^ the shoreline.
To eliminate this condition and to provide for better dilution and
dispersion of the wastewater, it is recommended that the final efflu-
ent be conveyed to the southerly channel as shown in Figure VI1-1.
The conveyance, which could oe by an excavated channel or
via a temporary pipeline, would proviae a vehicle for continuous
wastevater flow ana prevent stagnant conditions. If a channel is
excavated, a program to maintain the channel, including weed control,
as required should also be initiated.
Since the current assimilative capacity of the Piscataway
embayment is being exceeded by present wastewater loadings, it is
recommended that the effluent outfall, as originally proposed by
WRSC, be constructed as soon ?.s possible. In addition, provision
should be made to eliminate the discharge of untreated wastes.
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(ft
FIGURE 301
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C Expansion of the Piscataway Wastewater Treatment Facility and
Potomac Interceptor
| According to the 1969-1973 Sewerage Program of Wfk3C, the
_ existing plant is to be expanded by 25.0 mgd. It has been estimated
by WSSC that wastewater flow in the service area by I960 will be
nbout 30 mgd. Associated with the expansion program will be a 4.0
mgd advanced wastewater treatment plant.
Preliminary studies by CFS have indicated that the wastewater
treatment level for all discharges into the Potomac Estuary will have
to be provided as given below to meet established water quality
standards.
Parameter Percent Reduction
5-day BOD 95
(Biochemical Oxygen Demand)
TO" 85
(Total Kjeldahl Nitrogen)
I P(\ 95
(Phosphates)
Usinp; the projected population and current loading averages for the
entire Potomac Estuary, this will result in the wastewater loadings
from the' 30 mgd Piscataway facility as follows:
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VTi
Current Treated Loading Projected Treated Loadirr
Parameter (if/day) (#/day)
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,
Trcnleu loadings based on 95, ^'5, av.j. f}^ percent 1,01), Tur!, u,n.l
POi removal efficiency, respectively.
As can be seen when the ^rejected and current loadin/;c are
5-day BOD 635
T.J; 1*00
PO, 390
compared, the projected loadings to the Piscataway e-nbaymc-Mt, , <">ven
with addition of AWT, will be higher than from the existing 5.0 m^a
facility.
. Therefore, it, is recommended tnat the ef fluent f^om tnc
existing plant and the proposed expansion be conveyed to the Potomac
Estuary.
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