HomeMy WebLinkAboutT13N R4W SEC 32 General InformationMUNICIPALITY OF ANCHORAGE
MEMORANDUM
DATE: November 27, 1990
TO:
Lee Browning, P.E., Manager
Environmental Services
THRU:
FROM:
SUBJECT:
John Smith, P.E., Program Manager
On-site Services
Robert W. Robinson, Civil Engineer ~
On-site Services
Salvation Army Clitheroe Center On-site Wastewater
Disposal Facilities
During several recent on-site field inspections (including one
septic tank pumping operation) it was concluded that the
existing on-site wastewater absorption system is undersized
and/or experiencing progressive failure. Subsequent to this
conclusion, cost estimates have been made and attached hereto,
to rejuvenate (by hydrogen peroxide injection) the existing
system(s); to enlarge the existing system(s); to construct
another wastewater disposal system capable of serving the
addition of an inebriate sleep-off facility. In preparing these
costs estimates, the following 'assumptions were made:
1. The integritz of the existing 10,000 gallon septic tank
is satisfactory.
2. The original absorption bed is tied in with the upgrade
bed installed in May, 1985 and are both receiving
effluent discharged from the septic tank.
3. The accepting soil underlying the upgrade bed and the
new bed will perc between 16 and 30 minutes per inch.
4. The occupancy of the sleep-off facility will be 70
persons including patients and staff.
5. The existing well will adequately handle the increased
fresh water load demand of a sleep-off facility.
The first of the attached cost estimates covers the rejuvenation
of the two existing beds with a hydrogen peroxide treatment.
Assuming that the existing absorption beds have been clogged
with grease and/or other materials carried over from the septic
tank, the probability of success of this type treatment is
estimated to be 60%. The cost of this treatment is estimated to
be $26,800.
Lee Browning, P.E., Manager
Environmental Services
November 27, 1990
Page Two
The second cost estimate is for upgrading the existing
subsurface absorption fields by adding another bed containing
6,725 square feet of absorption area. The sizing of the
additional bed was based on the difference (in square feet)
between the existing beds and the calculated total absorption
area required. The required absorption area is based on an
occupancy of 105 persons generating 75 gallons per day per
person (UPC 88 Edition) and an application rate of 0.6 gallons
per day per square foot (EPA and ADEC specified application
rate). This cost estimate is made under the assumption that the
underlying accepting soil stratum will have a percolation rate
of 30 minutes per inch or faster. In view of the large basal
bed area (80'x 85') it is deemed that a pressure distribution
system is desirable, and the cost estimate is based thereon.
The estimated cost of upgrading the existing system to handle
only the Clitheroe Treatment Facility is $42,400.
The third cost estimate is for adding additional wastewater
disposal facilities to facilitate the anticipated volume
generated by a "sleep-off center" built at the Clitheroe
Facility. The design of this system is based on a patient and
staff load of 70 persons generating 75 gallons per day of
wastewater. The required absorption area (basal bed) of 8,750
square feet is based on the assumption that the underlying
accepting soil stratum will have a percolation rate of 30
minutes per inch or faster. As in the case of the upgrade
system, a pressure distribution system is deemed to be desirable
and the cost estimate was made accordingly. The ideal location
for this new system is in the cultivated area approximately 200
feet west of the main building complex. It is understood that
this area belongs to the Municipality and is leased on a
year-to-year basis for agricultural purposes. The estimated
cost of installing this new wastewater disposal system for the
proposed sleep-off center is $53,800.
Cost Estimates for Upgrading
Wastewater Disposal Systems
Salvation Army Clitheroe Facility
Regeneration of Existing Beds
(Assuming that the existing and new bed are
A. Pretreatment
1. Run adequacy test on each system
a. Blind off each system
b. Adequacy test each system
c.
d.
tied together)
$ 500
2,000
Adequacy test combined systems 1,000
Pump out each bed (40,000 gallons) 2,000
Subtotal: $ 5,500
Hydrogen Peroxide Treatment
Note: Use an application rate of 0.4 gallons at 12 1/2%
of hydrogen peroxide per square foot o~ bed.. 55
gallons at 50% hydrogen peroxide miked with'll0 gallons
of water will make 165 gallons of 12 1/2% hydrogen
peroxide.
1. Blending/pumping hydrogen peroxide $ 4,500
2. Hydrogen peroxide cost
a. 6,000 square feet + 6,400 square feet =
12,400 square feet
0.4 gallons hydrogen peroxide per square feet
x 12,400 square feet = 4,960 gallons of 12
1/2% hydrogen peroxide required.
4,960 divided by 165 = 30 drums 50% hydrogen
peroxide: 30 x $420 = 12,600
Deposit on drums @ $40.00 ea.= 1,200
3. Post treatment tests 3,000
Subtotal: $21,300
GRAND TOTAL A & B: $26,800
Cost Estimates f~)Upgrading
Wastewater Disposal Systems
Salvation Army Clitheroe Facility
II. Enlarge Existing Bed (Upgrade Only)
ao
Using Table I-3 of the 1982 Edition of the Uniform
Plumbing Code, with a total of 105 patients and staff,
a total of 7,875 gallons of wastwater will be generated
per day. Based on the EPA recommended application rate
of 0.6 gallons per day per square feet, the required
absorption area is 13,125 square feet. Using the 6,400
square foot of existing bed, and additional 6,725
square foot of bed is needed. This would require a
basal bed of 80' x 85'. There is adequate room near
the existing bed to accommodate this enlargement or
additional bed. For a bed of these dimensions, a
pressure distribution system will provide a more even
distribution of-the effluent throughout the basal bed
area.
1. 2,000 gallon lift s~ation with a duplex 75 gallons
per minute pump $ 6,500
2. 1 1/4" pressure distribution system (materials &
labor) 6,000
3. Tie into existing bed (materials & labor) 2,000
4, Bed excavation/gravel installed and
backfilling 20,500
5. Install 2,000 gallon lift station (excavation and
labor) 1,500
6. Electrical costs 1,000
7. Excavate/perc/monitor 4 locations 2,400
8. Engineering design/install/inspect 1,500
9. Miscellaneous 1.000
TOTAL COST OF UPGRADE: $42,400
Cost Estimates f~[~pgrading
Wastewater Disposal Systems
Salvation Army Clitheroe Facility
III.
Install System for Sleep-Off Facility
(60 patients + staff of 10)
A. Wastewater disposal system design
1. Wastewaher generated = 70 x 75 gpd = 5,250
gallons.
2. Absorption area required ~ 5,250 divided by
0.6 = 8,750 square feet; 80' x 110' x 4 1/2'
bed required.
3. Septic tank required = (5,250 x .75) = 1,125
= 5,062 gallons. Use 6,000 gallon septic
tank.
4. 2,000 gallon (1,860 gallons) lift station.
Bo
Wastewater Disposal
1.
2.
3.
System Costs
6,000 gallon septic tank $ 6,000
Excavate and install septic tank' 2,500
2,000 gallon lift station with duplex
pumps 6,500
Install lift station (excavate and
labor) 1,500
1 1/4" pressure distribution piping (labor
and materials) 7,300
Bed excavation/gravel/backing 24,500
o
8.
9.
10.
(326 yards gravel
excavation)
Electrical costs
Excavate/perc/monitor 4 test holes
Engineering design/installation and
inspection
Miscellaneous
and 1,470 cubic yards
1,000
2,000
1,500
1.000
TOTAL COSTS: $53,800
RWR:ljm300
MUNICIPALITY OF ANCHORAGE
Department of Health and Human Services
MEMORANDUM
DATE: November 14, 1990
TO:
THRU:
FROM:
Lee Browning, P.E., Manager, Environmental Services
John Smith, P.E., Program Manager, On-site Services~
Robert W. Robinson, Civil Engineer, On-site Services
SUBJECT: Existing On-site Water and Wastewater Disposal
Facilities Salvation Army Clitheroe Detox Center
Pursuant to your recent request, we have conducted a study of
the on-site water and wastewater disposal facilities serving the
Salvation Army Clitheroe Detox Center, formerly known as the
Honor Farm. As part of our study efforts, we have found that
there are very few records available which document the design
and construction of the systems and that the accuracy of these
records is questionable.
In May, 1985 the existing bed system (dimensions unknown) was
upgraded by adding an additional 80'x 80'x 4.5' absorption bed
and a new 10,000 gallon.septic tank. From available records and
field inspections, it is not evident whether the old bed is
still tied into the system. 'During ~he design phase of the new
system, two different wastewater flow rates were provided.
These rates were 4,500 gallons per day'and 5,500 gallons per
day. According to the in-house maintenance foreman (Mr. John
Warner) the water usage from the on-site well was metered at a
rate of 6,000 gallons per day. The following information is
pertinent to the design of the current system:
2 o
Two soil tests were taken in November, 1984, one near the
existing absorption bed (TH-l) and one near the proposed new
absorption bed (TH-2). The soils of TH-1 were too tight to
perc and the soils of TH-2 perced 18.5 minutes/inch. The
site of TH-2 is approximately 25 feet west of the absorption
bed, and may not accurately reflect the soil characteristics
underlying the major portion of the absorption system.
The additional absorption bed installed in June, 1985
appears to be undersized by a factor of at least 50%. Based
on metered water volumes from the on-site well, the system
should have been designed to handle a minimum of 6,000
gallons of wastewate~ per day. Based on design criteria
~Kids Are Our Future
Lee Browning, P.E.
November 14, 1990
Page Two
taken from Table 1-3 of the 1982 Edition of the Uniform
Plumbing Code, the system should be sized to handle 75
gallons per person per day, which equates to 7,875 gallons
per day for the 105 patients and staff personnel. Using an
application rate of 0.6 gallons per day/square feet (EPA and
ADEC specified application rates), the basal bed area should
be 10,000 square feet for 6,000 gallons per day or 13,125
square feet for 7,875 gallons per day. The actual dimension
of the new bed is 80'x 80' for a basal bed area of 6,400
square feet.
3 o
According to the Clitheroe Center maintenance foreman and
confirmed by MOA Public Works, the septic tank (10,000
gallon volume) is scheduled for routine pumping every six
months. The pumping contractor's records show that during
the last 4 years, the septic tank was pumped ten times with
the volumes pumped ranging from 12,000 to 15,400 gallons.
Since the capacity of the tank is 10,000 gallons, it becomes
apparent that the absorption bed is back flowing into the
tank during the pumping operation. During a site visit on
October 30, 1990, Messrs. John Smith and Robby Robinson
observed standing water in the standpipe in the bed at
approximately 8 inches below ground level. The system was
pumped on November 8, 1990. After pumping water levels in
bed were measured at depth of approximately 4.5 Ft. These
measurements further support the conclusion that the bed is
periodically surcharged and may be back flowing into the
septic tank when the tank is pumped. Dr. Ray Dexter at the
Center advises that it isn't unusual to have to curtail
showers and laundry use because the disposal system becomes
surcharged.
Based on the above data and information, it is concluded that
(1) the existing system is operating at its absolute maximum
capacity and should probably be upgraded if continued maximum
usage is anticipated and (2) the activities of the Center cannot
be expanded without expanding and/or upgrading the existing
wastewater disposal facilities.
The Clitheroe Center is served by a Class "A" well that is on
site. We have not been successful in obtaining a well log or
pump test information. ADEC records indicate that water
produced from the well meets State of Alaska and EPA drinking
water standards.
Tom Fink,
Mayor
N un c pahty AnclXorage
Department of Health and Human Services
825 "L" Street
P.O. Box 196650 Anchorage, Alaska 99519-6650
November 13, 1990
John Warner, Maintenance Superintendent
Salvation Army Clitheroe Center
PO Box 190567
Anchorage, Alaska 99519-0567
Dear Mr. Warner:
As we discussed yesterday, there are some operating guidelines
that can be easily implemented which should enhance the overall
performance of your on-site septic system.
These are as follows:
It is strongly recommended that the periodic injection
of the enzyme additive into the septic tank be
immediately discontinued.
2 o
The kitchen grease trap should be serviced not less
than once every other day.
o
Those working in the kitchen shouid be instructed on
the use of the garbage disposal unit. Continuous
caution should be exercised against placing anything in
the disposal that will not readily and quickly
biodegrade. Some items which definitely should not be
run through a garbage disposal unit are meat fats,
bones, butter, grease, oil, fiberous vegetables, citrus
rinds, egg shells, etc.
The other primary source of problems with the
performance of a septic tank is what is flushed into
the toilets or poured into utility/mop sinks. Only
biodegradable soaps and detergents should be used.
Paper products other than toilet paper should not be
put into toilets. Sanitary napkins, ashtray contents,
rags/bandages, etc. should never be flushed down the
toilets. Moderation should be exercised in the use of
bleaches and disinfectants.
John Warner
Clitheroe Center
November 9, 1990
Page Two
5o In addition to the proper use and maintenance of the
septic system, the reduction of water usage will
enhance the day to day performance and overall
longevity of a septic system. A surprising reduction
in water use can be realized with a few simple and
inexpensive precautions. A few water savings measures
are (1) repair any leaking fixture or appliance, (2)
install water flow restriction devices on all showers
and fixtures, (3) reduce the volume of water use per
toilet flushing, (4) only use the dish and clothes
washing equipment for full loads, and (5) encourage all
staff and patients to practice water conservation.
I believe these helpful hints will improve the overall
performance of your septic tank.
If you have any questions or need any assistance with your
septic system, please feel free to call me. I am including a
couple of copies of a handout brochure that may also prove to be
helpful to you and the kitchen staff.
Robert W. Robinson
Civil Engineer
On-site Services
RWR/ljm:33
CC:
Dick Raynor, Public Works
John Smith, P.E., Program Manager, On-site Services
Lee Browning, P.E., Manager, Environmental Services