001
PAGGI & MARTIN
Consulting Engineers & Land S ur'Jeyors
CDI
54-56 Main Street
Poughkeepsie, New Yark 12601
9 1 4--4-7 1- 78 9 8
January 21, 1993
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Hayward & Pakan Associates &
Rudolph E. Lapar, P.E., P.C.
321 Main Mall
Poughkeepsie, New York 12601
Attention:
Donald G. Tomlins, P.E.
Town of Wappinger Wastewater Flow
Into the Tri-Municipal System
Dear Mr. Tomlins:
Reference:
In your correspondence of March 2, 1992, you expressed your concern
of possible odor development due to low initial flows from the Town of
Wappinger transmission line at its discharge point. Since that time, we
have been developing our final design, included within, provisions for
odor control.
In our analysis of the velocities and travel times for the Town of
Wappinger transmission line, we found that velocities within certain
sections of the transmission line will exhibit low velocities, and
therefore, longer travel times during our initial wastewater flows. With
these low initial velocities, we decided to investigate the potential for
sulfide buildup within the sewer during these initial flows.
In our calculation for predicting sulfide buildup, we employed both the
Pomeroy "Z" equation and the Pomeroy and Parkhurst equation. These
equations were taken from the American Society of Civil Engineers and
Water Pollution Control Federation manual "Gravity Sanitary Sewer
Design and Construction", along with the EPA design manual, "Odor and
Corrosion Control in Sanitary Sewage Systems and Treatment Plant".
In our analysis, the entire sewer transmission line was divided into four
gravity reaches, starting at the discharge of the proposed Rockingham
Farms pump station at Cedar Hill Road and proceeding downstream
towards the existing Village of Wappingers Falls pump station.
Joseph E. Paggi, Jr., P.E.
Ernst Martin, Jr., r.E., L.S.
January 21, 1993
Page Two
Hayward & Pakan Associates &
Rudolph E. Lapar, P.E., P.C.
321 Main Mall
Poughkeepsie, New York 12601
Attention:
Reference:
Donald G. Tomlins, P.E.
Town of Wappinger Wastewater Flow
Into the Tri-Municipal System
The first reach, from Cedar Hill Road along Spookhill to Myers Corners
Road, was analyzed and then introduced into the subsequent reach of
the 24 inch line down Myers Corners Road to the proposed Oakwood
Pump Station discharge manhole. In addition, all collector lines entering
along the reach were studied in order to generate more reliable
estimates for the sulfide levels generated in the sewer transmission
lines.
As a result of our analysis using the aforementioned equations, sulfide
generation will generally occur, consequently an odor problem could
arise.
In response to our findings, we contacted Camo Pollution Control,
operators of wastewater systems throughout this area, to set up field
visits to other facilities integrating odor control equipment.
One facility of particular interest was the Town of Fishkill pump station
and force main which travels from the Town of Fishkill (Brinckerhoff) to
the City of Beacon, at which time the force main discharges into a
gravity sewer that travels approximately three miles to the treatment
plant. A chemical solution is injected at the Town of Fishkill pump
station to control sulfide generation in the force main, where problems
generally occur, and control odor problems that could develop in the
gravity sewer downstream.
During the time we were investigating the Town of Fishkill facility, City
of Beacon residents were filing complaints about odors emanating from
the gravity sewer downstream of the Town of Fishkill force main
discharge. Camo Pollution Control was notified of the complaints, and
contacted Davis Water and Waste Industries, Inc., to investigate the
problem.
January 21, 1993
Page Three
Hayward & Pakan Associates &
Rudolph E. Lapar, P.E., P.C.
321 Main Mall
Poughkeepsie, New York '-2601
Attention:
Donald G. Tomlins, P.E.
Town of Wappinger Wastewater Flow
Into the Tri-Municipal System
Reference:
A representative of Davis inspected the problem and recommended an
increased dosage of chemical solution to obtain a residual downstream
of the force main (gravity sewer) and alleviate sulfide generation, and
corresponding odors.
Once the chemical solution dosage was adjusted, the odors present in
the gravity sewer were sufficiently eliminated.
With the successful elimination of the sewage odors along the gravity
line resulting from the adjustment of chemical injection into the force
main, we contacted the Process Division of Davis Water and Waste
Industries, Inc. to investigate the performance and results of their
equipment functioning in our system.
Upon contacting Davis Water and Waste Industries, Inc., we met with
their representative to obtain an overview of their chemical solution and
equipment, pursuant to the requirements of our system.
The main component of the system is their solution called "Bioxide", a
proprietary blend (Inorganic salt solution) which controls hydrogen
sulfide odors by way of a biological process rather than a chemical one.
The "Bioxide" solution is an aqueous solution of non-hazardous
substances as defined by the EP A CERCLA list. We have enclosed
literature and material safety data on the "Bioxide" solution for your
information.
All pertinent information on our gravity sewer reaches, as used in our
sulfide prediction calculations indicated previously in this report, and
force main was sent to Davis Process Division in order to generate a
computer model of our transmission system.
January 21, 1993
Page Four
Hayward & Pakan Associates &
Rudolph E. Lapar, P.E., P.C.
321 Main Mall
Poughkeepsie, New York 12601
Attention:
Donald G. Tomlins, P.E.
Town of Wappinger Wastewater Flow
Into the Tri-Municipal System
Reference:
Although the computer modeling which Davis Process commonly
generates is for force main applications, they can incorporate our gravity
reaches downstream into their model and obtain fairly accurate results.
Our system was analyzed, from the pump station through the gravity
trunk lines to our last manhole prior to the Village Pump Station, by
Davis Process Division with "Bioxide" injection at the proposed
Rockingham Farms pump station.
As a result of their analysis, the representative of Davis Process Division
feels that any hydrogen sulfide problems downstream in our system can
be controlled through adjusting the "Bioxide" dosage at the Rockingham
Farms pump station. Also, if necessary, a "Bioxide" installation could be
set up at the existing Oakwood Knolls sewer treatment plant which will
be the future site of a pump station, to assist in alleviating any odor
problems arising during the low initial flows.
Attached herein are copies of our correspondence with Davis Water and
Waste Industries, Inc and included in this correspondence is the data
utilized in our analysis for the gravity trunkline.
As you can see, the Pomeroy "Z" values calculated by Davis are
incorrect, and we sent a memo to Davis to correct these values (copy
enclosed). .
To insure the accuracy of their computer modeling of our system, we
contacted Davis to see if the incorrect "Z" values were used in their
analysis, however, Davis indicated that the "Z" values were hand
calculations, and their computer model utilizes detention times to
execute its analysis.
..
January 21, 1993
Page Five
Hayward & Pakan Associates &
Rudolph E. lapar, P.E., P.C.
321 Main Mall
Poughkeepsie, New York 12601
Attention:
Donald G. Tomlins, P.E.
Town of Wappinger Wastewater Flow
Into the Tri-Municipal System
Reference:
If there are any questions, concerns or request for additional
information, please do not hesitate to contact this office.
Very truly yours,
~~M~).
Charles R. Del Bene, Jr.
CRD:law
cc: Constance O. Smith, Town Supervisor
Town Board
Matthew Rudikoff
Camo Pollution Control
Dan 0' Connor, DCHD
Carol Garrity, Chairperson, Tri-Municipal Sewer Commission
89-077/2.2