TOWN CENTER SEWER ACTION GROUP
A Sub-Committee of The Harvard Board of Selectmen
Meeting Minutes Thursday November 13, 2008
Meeting called to order @ 7:30PM at Hapgood room
Attendees: Chris Ashley, Joe Sudol, Carrie Fraser, Wade Holtzman, Pat Jennings
Guests: Wayne Perry, PE and Associate, Norfolk-Ram, Fran Yanuskiewicz, PE and Senior VP Weston & Sampson
Meeting Summary
The updated engineering estimates for the proposed sewer district were reviewed by Wayne and Fran. Questions were asked and answered by committee members and attendees from the public.
Engineering presentation and Discussions:
Q&A:
Question: could the gravity pipe on Mass Ave could run the other way to the intersection of Mass Ave and Still River.
Answer: “maybe”, need to validate slopes
Question: can the Pond road pipe tie in to the Bromfield force main more directly:
Answer: yes, would be a good solution to use a low pressure force main to accomplish the collection and linkage.
Question: (citizen) There is a “rumor” around town that changing the flow composition will solve all of the plants problems
Answer: The composition change will help with the plant health. The plant is currently meeting permit. That said, there is an issue with de-nitrification process that needs to be resolved if much larger flows are expected (see below)
Question: what legal fees are expected
Answer: Engineers don’t anticipate significant legal fees. Mark Lanza will advise further once selectmen have reviewed proposal.
Question: what is the cost should an Environmental Impact exercise be required (felt to be an unlikely scenario by the engineers)
Answer: $50-100K
General discussion of design approach: gravity collection vs low pressure force main
The engineers suggested that we might consider the use of low pressure force mains for portions of the design. In the past they were told to disregard the low pressure force main approach due to unwillingness of property owners to deal with pump infrastructure required on each property to get the flow to the force main.
Pros and Cons of a low pressure force main approach:
Pros: cuts complexity of piping and installation of piping and costs of doing it by an estimated 30-50% because your depth is lower and you do less ledge excavation (slight savings due to smaller trench width); eliminates need to plan for infiltration inflow (ground water leaking into the pipes along the pipe length and reducing your overall headroom for amount of sewage able to process by 10%); can eliminate pumping stations
Cons: requires grinder pump at each property served (in front or side yard) which is a piece of equipment that requires a power source and can fail with power outage or in the normal course of equipment life
Anticipating ledge difficulties:
The engineer recommended we check with power, gas and DPW as to whether sub-surface ledge depths are known along the sewer route. If not, including a boring project to determine ledge characteristics is advisable as it pays for itself in costs of current and future projects. This additional work would involve using a Geoprobe/drill to sample at a 10 ft depth every 300 ft.
Cost of upgrading plant ($571K):
Wally the plant operator gave some input on what is needed going forward for the plant. The plant is currently meeting permit, continues to have problems on the de-nitrification end as it has had in the past. The DEP is concerned that if we take it up to its maximum that we are able to prove that hydraulically as well as load-wise it can handle it. The DEP wants confirmation that this will occur. Ramping up slowly to 18400 GPD would be a good idea.
Background:
Bio-clear creates nitrates and it needs to be de-gassed. As the load on the plant increases, the plant will have more difficulty in doing this well, the media used in the process gets clogged and sub-optimizes processing. Changing out the de-nitrification system for a new one is recommended for flows over 10K GPD and this upgrade would cost
Financing and betterments approach consulting:
Fran offered to provide and deliver a tutorial presentation on betterments and so forth. He also recommended going to the MA general laws web site and looking at session acts for examples of what other towns are doing.
Decisions:
¨ We need to reduce the anticipated costs. We would like to see the engineers recommend design changes that could reduce costs and make any other suggestions. In particular explore low pressure force main usage in the design.
¨ Fran agreed to include the work above in the context of a session at additional cost to consult on financing and betterments approach
Actions:
¨ Fran/Wayne: Cost estimate for sampling effort
¨ Wayne: circle pipe “legs” on the large scale plan, reduce, and provide to team
¨ Fran: send slides to Chris for review
¨ Chris: finalize expansion of contract to include consulting on financing and betterments approach and revised design proposal
¨ Chris: check with Rich Nota regarding any existing knowledge of ledge depths
¨ Chris: check TIP site to see if any Mass Highway (traffic improvements) are anticipated
¨ Carrie: send spreadsheet model to Wayne and Fran
The meeting was adjourned at 9: 27PM
Minutes recorded and submitted by Carrie Fraser - secretary, TCSAG
Accepted by the TCSAG November 20, 2008
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