January 13, 2011
West Cummington Congregational Church
Building Committee
Church Lane
Cummington, MA 01026
Subject: Effluent Disposal Alternatives – West Cummington Church Reconstruction
Dear Committee Members:
Berkshire Engineering Inc., at the Committee’s direction, conducted percolation testing and a soil evaluation at
the above noted property on November 10, 2010. The scope of this assessment was limited to Massachusetts
Department of Environmental Protection (MADEP) and Cummington Board of Health (CBH) required testing in
support of onsite sewage disposal. Subsequent to our site evaluation we have investigated three potential
design alternatives for the treatment and/ or disposal of effluent anticipated to be generated by the proposed
facility.
We understand it is the intention of the Building Committee to include two separate bathroom facilities at the
rear of the reconstructed church. Additionally, it is our understanding that MADEP and the CBH would consider
the eventual disposal method an “upgrade to a failed or non-conforming system” and treat it as such during
the permitting review process.
Through discussions with representatives of the Committee it is apparent that several factors are to be
weighed when evaluating the ultimate impact of any effluent disposal option. Some of these influences may
include an alternatives ability to maintain the previously existing aesthetic of the site, its ability to exhibit
“green” strategies with respect to sustainable redevelopment, and its ability to be readily constructible given
the difficult site conditions. These concerns coupled with inherent land constraints, an unsettled property line,
overall economic viability, roughly estimated approximate lifecycle cost, future maintenance burden,
constructability, and actual disposal demand versus modeled disposal demand have all been taken into
account while preparing the recommendations outlined below. It should be emphasized that all costs
estimates included in this evaluation are preliminary in nature and may not accurately reflect the actual
lifecycle costs associated with each option.
Option One - Composting toilets and complimentary grey water system
.The upside of this option is its ability to offer the greatest “visual” demonstration of green strategies of the
three potential strategies evaluated. Composters would serve as a reminder to all users that the facility was
designed and constructed with conservation and sustainability in mind. With that said we find several
shortcomings with this option from a practical standpoint. Composting toilets, as with all of the treatment and
disposal options, work best when maintained under ideal conditions. For composters, these ideal conditions
include very routine steady use with limited influent deviation or fluctuation. With significant use confined to
only a few hours every week, the composters are likely to sit inactive the rest of the time. The lack of
consistent moderated influent may adversely affect the composters’ ability to function as desired. Given the
nature of the proposed facility “shock loading” may be of concern. Composting toilets are not well suited for
such effluent characteristics. Additionally the overall square footage of the facility, regardless of actual use of
the composters, may void any potential manufacturer’s warrantee. It is not clear whether a manufacturer
would be willing to honor a warrantee claim, given the potential maximum occupant loading of the space
served coupled with the total number of units installed. Composting units are used to treat blackwater only,
leaving greywater to be disposed of elsewhere. Title Five regulations require that when greywater is to be
disposed of onsite, it be treated in a fashion very similar to traditional septic effluent. Regulations allow for the
subsurface disposal of greywater to occur somewhat closer to the groundwater table than blackwater, and
with a somewhat reduced disposal footprint. A greywater infiltration system could potentially be supported on
the site to the West of the reconstructed facility. This location would require a formal property line agreement
be reached with the abutting property, which we understand may not be an option at this point. Additionally,
greywater disposal will require a mounded system extending approximately 2.5’ above the existing highest
grade elevation in this location. Greywater disposal will also require the installation of a septic treatment tank,
a pump chamber, and appurtenant plumbing and electrical works. We would anticipate the installation of
tankage to require some measure of ledge removal. Additionally the operations and maintenance of the
treatment tank, the pump chamber, and the alarm panel require a minimal yearly outlay. Given the limited use
of the facility, we would not anticipate electricity cost associated with the pump chamber to be overly
burdensome.
The need to separately treat grey water from hand rinsing and other activities hampers the financial viability of
incorporating composting toilets in to this project. We feel the additional economic outlay needed to install
and maintain the units and appurtenant works could be better directed towards another high visibility green
solution. Implementation of a separate prominent green strategy elsewhere on the project would likely realize
a greater financial and environmental return on investment.
Option One – Estimated Costs:
Two remote composting toilets with appurtenant works = $6,500
Septic Tank, Pump Chamber, and Alarm Panel = $6,000
Grey water Infiltration Field = $13,000
Ledge Removal = $5,000
Periodic maintenance = $100/year
Electrical Expenditure = $15/year
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Estimated Total 30 Year Lifecycle Cost* = $32,267.84
*
= Based on a MARR of 5% and a 30 year life expectancy.Option Two - Pretreated Innovative/ Alternative Subsurface Sewage Disposal System.
Traditional onsite disposal is not an acceptable solution for the subject parcel due to the shallow to bedrock
conditions encountered. Title Five regulations require the use of pretreatment or innovative alternative (I/A)
technologies on any site where four feet of naturally occurring pervious soil is not present. Soil analysis at the
parcel indicated approximately 2’ to 2.5’ (the minimum allowable) of naturally occurring pervious material was
present, as defined by Title Five regulations. A pretreated I/A system for the subject parcel would work a
follows: Effluent would first pass through an aerated septic tank or similar biological reactor. From here it
would continue on to a pump chamber, and finally be distributed to a subsurface infiltration field under
pressure. The electrical demand of the pretreatment cannot be ignored, as it runs regardless of influent
loading.
The pump chamber infrastructure required is identical to that needed by a greywater system. Finally, Title Five
regulations require that an operations and maintenance contract be in place with a licensed provider prior to
commissioning any I/A system. The price of this contract can vary depending on the type of technology
employed; however a rough estimate of +/-$700 per year has been witnessed in similar facilities. A pretreated
I/A blackwater disposal field will require a mounded system extending approximately 3.5’ above the existing
highest grade adjacent to the western extent of the proposed building. A blackwater infiltration system could
only be supported on the site, if at all, after a favorable property line agreement is reached with the abutting
property owner. Tankage required for a pretreated I/A system would necessitate the excavation of slightly
more ledge than that needed to accommodate greywater tankage.
Option Two – Estimated Costs
Pretreatment Unit = $7,000
Pump Chamber and Alarm Panel = $4,000
Subsurface Infiltration Field = $22,000
Ledge removal = $7,000
Maintenance and Inspection Contract = $700/year
Electrical Expenditure = $75/year
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Estimated Lifecycle Cost* = $51,915.63
*
= Based on a MARR of 5% and a 30 year life expectancy.Option Three - Onsite tight tank (holding tank) for offsite disposal.
The final method evaluated calls for the installation of an onsite holding tank. The tank would be equipped
with alarms similar to those required by a pump chamber in options one and two. All effluent generated would
be collected in the tight tank until a predetermined storage limit is reached. In addition to this limit, the tank
includes significant over-alarm storage. When comfortable capacity is reached a septic disposal company is
retained to pump the tank and subsequently provide offsite disposal of the effluent. In addition to traditional
audible and visual alarms, the tank could be equipped with an automatic phone dialer. This system could be
set up to notify various persons tasked with the systems operations or notify a preselected septic service
directly. This option would require the least alteration to the existing site aesthetic as no increase in surface
elevation would be anticipated. Additionally, the tank could likely be situated where the greatest soil depths
were noted during geotechnical evaluation. This could potentially significantly reduce or eliminate the need
for ledge removal. The importance of low flow plumbing fixtures, water conservation methods, and
elimination of groundwater infiltration into the system is greatest with this option. A leaky plumbing fixture or
inadvertently leaving a fixture running can significantly increase the interval at which the system must be
pumped. This proposal anticipates the installation of a 2500 gallon tight tank with approximately 1200 gallons
of that devoted to operational capacity (with the rest reserved for over alarm storage). It is our understanding
that a similar facility in the village, which also hosts community meals and is equipped with a kitchen, has
shown a metered water usage of less than 2 gallons per day. Our estimate of actual flows conservatively
assumes that the reconstructed facility will use approximately the same amount of water, despite not being
equipped with a kitchen. This would result in the need for pumping to arise fewer than once a year.
Option Three – Estimated Costs:
Tight Tank = $7,000
Alarm Panel = $1,500
Remote Dialing Option = $500 initial installation plus $250/year
Electrical Expenditure = +/-$0/year
Pumping and Disposal
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1 = $400/yearEstimated Total 30 Year Lifecycle Cost w/o remote dialing* = $14,649.00
Estimated Total 30 Year Lifecycle Cost with remote dialing* = $18,992.13
*
= Based on a MARR of 5% and a 30 year life expectancy.1
= Pumping and disposal fee based on average of one pumping per year.For the reasons outlined above, it is the professional recommendation of Berkshire Engineering Inc. that the
West Cummington Congregational Church Building Committee pursue the permitting, installation, and
operation of a tight tank at the subject parcel. It is our assumption, based on the flow number for a similar
facility provided to us by the Committee, and given the anticipated sporadic and limited use of sanitary
facilities at the church, that a tight tank will provided the greatest overall benefit to the project. The cost
savings realized through pursuing option three could then potentially be used to invest in a more viable green
enhancement strategy elsewhere in the redevelopment.
After reviewing this evaluation, please feel free to contact the undersigned to address any questions or concerns. Additionally, please advise us as to how you would like to proceed with the permitting and design
efforts.
Respectfully Submitted,
Nicholas Andersen
Civil Engineer/ Soil Evaluator
Berkshire Engineering, Inc.
Attachment:
MADEP Form 12 – Percolation Test
MADEP Form 11 – Soil Suitability Assessment for Onsite Sewage Disposal
