NC0000272_more information (received)_20230925

Responses to Questions from DWR Staff & the Consultants for Town of Canton
1. Has the capacity of the low lift/influent pump station been evaluated to determine if the station
can be operated at the projected lower flows?
There are four pumps in the low lift sump all on level control. Two of the four pumps are variable
speed pumps that can be adjusted up or down to pump more or less. No trouble is anticipated in
pumping a much lower flow. Historically the mill has had experience pumping much lower flows
during routine outages and especially during cold mill outages.
2. Will new smaller influent wastewater pumps be required?
No. See Response to Item 1 above.
3. It has been assumed that the plant will operate in the future using the extended aeration
biological treatment process utilizing one or more of the existing aeration basins. Has Evergreen
completed a treatability study to determine if one of the smaller basins can be used for the
treatment?
No treatability study has been completed specifically on Town of Canton (TOC) effluent, but there
are many examples in the nation today of activated sludge successfully treating Municipal
Wastewater. Additionally, based on recent performance, the system operation has adapted well to
the reduced loading.
4. The Town of Canton currently disinfects the majority of the town's flow to the Evergreen plant. It
would seem that this process will be detrimental to the extended aeration process once the
majority of the mill flow is eliminated. At what point in the future does Evergreen desire to have
the Town cease the disinfection/chlorination process of influent flow?
Disinfecting untreated municipal effluent prior to its being treated in an activated sludge treatment
plant is not detrimental to the activated sludge process as long as there is good control of the
chlorine addition such that large overfeed situations do not occur. In fact, it is quite common for
activated sludge systems to employ the use of chlorine to stop or control outbreaks of filamentous
bacteria which cause high TSS and BOD in treated effluent. The TOC should continue to disinfect its
wastewater prior to the WWTP and to improve its control of that process to include more accurate
and reliable flow measurement, flow proportional addition of sodium hypochlorite, and periodic
chlorine demand testing of the Town's wastewater to determine the proper amount of chlorine
needed to disinfect the wastewater. Additionally, stopping chlorination of the TOC wastewater prior
to the WWTP would also cause a concern of potential exposure of our WWTP employees to "raw
sewage". As discussed further below in response to Item 1p, Evergreen believes the Town needs to
complete its proposed project to locate a disinfection station on PTVE property.

5. Does Evergreen have a projected flow from the landfill leachate that will require treatment in the
future? Do they have leachate flow data records they can share? Is there a project flow for any
groundwater remediation and stormwater?
The mill's landfill leachate system has the capacity to pump up to 0.2 MGD to the WWTP. Typical
flows are estimated to around 0.1 MGD. Stormwater flow from the mill is estimated to be an
average flow of 0.41 MGD.
With regard to groundwater remediation, the use of the WWTP to treat groundwater as part of the
black liquor removal action is still being evaluated. The September 2023 sampling event should
provide information needed to determine whether the pump and treat system is appropriate for the
site, and if it is, to provide information for the design of such a system. If pump and treat is selected
and approved for the black liquor removal action, projections on flow and contaminant loading
would be developed in association with the design of the pump and treat system.
6. Will Evergreen plan on some type of pretreatment for leachate flow? And when/where is it
anticipated pretreatment will be installed?
No pretreatment is planned.
7. It is understood that the current flow pattern proposed by Evergreen is that the low lift/influent
pump station will pump to one of the three primary clarifiers for treatment. Flow from the
primary clarifier will then flow to one of the smaller aeration basins, then to one of the secondary
clarifiers, with final discharge through the effluent parshall flume for flow measurement and
reaeration utilizing the step aerator prior to discharge.
Correct.
8. Are there existing sludge pumps for the removal of primary sludge from the primary clarifiers?
Yes, there are six existing primary sludge pumps.
9. What are these pump capacities?
Each pump can pump from 3.5 to 154 gpm.
10. Can they operate efficiently at the lower plant flows?
Yes, the pumps are variable speed. Each pump can be adjusted up or down and the number of
pumps being operated can also be varied to adjust flow up or down.
11. Where is sludge wasted prior to being dewatered on the existing belt filter presses?
Secondary sludge is wasted to the Low -lift sump.

12. Has Evergreen confirmed that the primary clarifiers will leave adequate nutrients in the
wastewater stream to the aeration basins to sustain the biological process without the need for
supplemental nutrients?
Based upon analysis of TOC's wastewater completed to date, there appears to be enough nitrogen
and phosphorus to drive the BOD reduction. However, due to the inoperability of the Town's
flowmeter no flow can be measured, so a complete determination cannot be made until that flow
meter is reliably operating. If future conditions dictate that the available nutrients in the Town's
influent are insufficient to support healthy biomass formation, nutrient addition can be implemented
as was historically done by the mill.
Evergreen expects that the Town will replace or repair its flowmeter so that it can provide reliable
measurements of domestic wastewater influent to the WWTP.
13. Is there a dedicated force main to allow flow from the low lift/influent pump station to the
aeration basins?
14. What is the condition of the platform aeration equipment in each of the aeration basins? The
Town recommends that consideration be given to replace the platform aeration equipment with
floating surface aerators and mixers to treat the lower flow.
There is considerable life remaining in the existing aeration equipment and these aerators provide
more than the necessary amount of oxygen and mixing. No replacement is being considered.
15. Has the secondary sludge pump station been evaluated to determine that the pumps can be
operated at a lower capacity for the future lower wastewater flow?
There are both gate and globe valves on the discharge lines on the secondary sludge pumps that
accommodate adjusting of flow. A secondary sludge pump station is not needed and is not being
evaluated.
16. Is piping in place to allow secondary sludge flow to be pumped to the aeration basin?
Yes, the RAS is pumped back to the front end of the aeration system where it is combined with the
Primary Clarifier overflow wastewater. The combined stream then flows to the aeration basins.
17. Which tank is used for wasting secondary sludge for digestion/stabilization prior to dewatering
and disposal?
Digestion/stabilization is not always employed, but when it is employed its typically basin AB2.

18. Will the existing parshall flume be modified to accurately measure the lower flow?
Evergreen has extensive operating experience using the existing parshall flume to measure flow at
lower flows during routine and cold mill outages where flow has been below 4 MGD. The existing
flume gives reasonable and consistent data during these low flow periods.
19. What is the plan for effluent disinfection? Will a new tank or basin be built for the chlorination
process?
There is no plan to add a disinfection process to the existing treatment system. The mill will
discontinue use of water from the Pigeon River in mid- to late -October, and so it will no longer be
disinfecting raw water from the Pigeon River at the Hill Filtration Plant. The other source of fecal
coliform in the wastewater is TOC's domestic wastewater. Evergreen expects the Town to continue to
chlorinate its domestic wastewater prior to their wastewater flowing to the WWTP.
Evergreen does have concerns that: (1) the Town's chlorination system does not have a chlorine
contact chamber to the system may not be providing adequate contact time to sufficiently disinfect
fecal coliform in the Town's domestic wastewater; and (2) the Town's disinfection system has a
constant chlorine feed rate that does not adjust for higher influent rates due to rain events and
associated infiltration of rainwater to the Town's collection system. During significant rain events, the
flow of domestic rainwater from the Town to the WWTP can double, but the Town's disinfection
system does not increase the flow of chlorine during these periods.
After a rash of fecal exceedances going back to 2019, the Town engaged hired McGill & Associates
Engineering to design a disinfection system that addressed these concerns. The new disinfection
system was to be installed by the Town by September 2022, but installation of the system never
commenced, and the Town continues to disinfect its domestic wastewater using the old system.
Evergreen is obtaining field coliform test kits that can be used to obtain more real-time data of fecal
coliform levels in the post -disinfection domestic wastewater from the Town to evaluate the
adequacy of the Town's existing disinfection system at various flow rates. If Evergreen's concerns are
confirmed, Evergreen will to work with the Town to address any deficiencies in the Town's
disinfection system.