NC0020354_Correspondence_20070710

NPDES DOCUMENT !MCANNINO COVER SHEET
NPDES Permit:
NC0020354
Pittsboro WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Technical Correction
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
July 10, 2007
This document is printed on reuse paper - ignore any
eontent on the reirerse side

Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P. E. Director
Division of Water Quality
Coleen H. Sullins, Deputy Director
Division of Water Quality
MEMORANDUM
TO:
FROM:
SUBJECT:
July 10, 2007
Morella Sanchez -King, Ph.D., P.E.
Hobbs, Upchurch & Associates
Hannah Stallings
Division of Water Quality
Chatham County
Pittsboro EIS — Initial Review for Completeness
The Planning Section of the Division of Water Quality has the following concerns:
1. Page 4: The Project Description should mention that the project would be completed in
phases.
2. Pages 4 states "A pump station will be installed at the headworks of the existing WWTP to
transfer a portion of the raw effluent to the new WWTP." Why won't the entire 4.0 MGD be
transferred for treatment at the new facility?
3. Page 4 — The project definition should include some mention of the reuse and other non -
discharge efforts, to the extent they are integral to the project. At a minimum, it is worth
noting the Town's broader, strategy similar to the description in the first paragraph on page
13.
4. Page 7 mentions that parts of the current WWTP will be used for the Phase I expansion. Will
these facilities also be used in the proposed new 4.0 MGD WWTP or will it be completely
independent of the Robeson Creek WWTP?
5. Page 10 states " the proposed Pittsboro wastewater treatment facility will not rely on the
components of the existing plant due to their limited capacity and age." This conflicts with
information presented on page 7. Please amend appropriately.
6. Page 10 — As this section indicates, concentration and mass limits are different in nature and
are used for different purposes. The current permit includes a total phosphorus (TP)
concentration limit of 2.0 mg/L, which the Division has long applied to ensure a minimum
level of phosphorus treatment at WWTPs across the Jordan Reservoir watershed. Because
Pittsboro's permit has no mass limit for phosphorus, please describe the mass value here as
the "equivalent mass load" or similar to avoid any confusion on this point.
7. In the third paragraph on page 10, please note whether the plant exceeded it's 2.0 mg/L

quarterly average limit due to the episodes of higher TP concentrations.
8. Page 11: • Please reference the 2005 Cape Fear River Basinwide Water Quality Plan and the
draft 2006 Integrated Report; both are on-line. This section should be updated using these
more recent documents.
9. Page 16 states "Several proposed residential developments in the Pittsboro area will use most
of the remaining WWTP capacity." However, page 14 states "These projects were able to
proceed because they incorporated non -discharge wastewater systems in their design, rather
than attempting to obtain treatment capacity from the Town." Please amend as appropriate.
10. Page 16 states "this EIS investigates the environmental impacts associated with the
construction of a 4-MGD WWTP, discharging 27,514 lb/yr of TN and 3,731 lb/yr of TP
ultimately delivered to Jordan Lake."
a. In order to avoid confusion over the location of the actual discharge point, please
amend this to state that the effluent will be discharged to the Haw River.
b. This segment of the text needs to be amended to reflect that the EIS is also factoring
in nondischarge alternatives for disposal of effluent.
11. The message referenced in the last paragraph on page 16 is missing from exhibit G (copy
attached).
12. Table 8 on page 19 and text on page 20 refer to project E-SRL-T02-0053 that received a
FNSI from CG&L for a pump station, forcemain, and elevated storage tank for reuse at the
3M facility. Also, page 20 states "Using cheaper reclaimed wastewater instead, 3M expects
to use up to 0.3 MGD at full production capacity, and about 5.0 million gallons per month
(0.17 MGD). Pittsboro has also requested that 3M make provisions to land apply its unused
reuse water when production needs are low."
The FNSI received for this project was to cover a 20-year plan by the county (with
cooperation from town officials) for disposal of the effluent from the Pittsboro WWTP. It
seems that the currently proposed project disturbs the planning horizon for the former CG&L
project. Please clarify.
13. Several locations in the EIS outline developing nondischarge plans that Pittsboro has for its
wastewater effluent:
a. Page 7 states "It is anticipated that a portion of the treatment plant effluent will be
used in reclaimed water uses, such as irrigation and industrial uses."
b. Page 18: Table 8 lists potential reuse sites that have been identified for accepting
water from the Pittsboro WWTP.
c. Page 20 states "The planned River Oaks development northeast of town is expected to
begin accepting 0.20 MGD of effluent for irrigation in 2008, under contract to
Pittsboro. The Town is hoping to contract with other landowners and developers close
to the proposed 3M reuse line in order to minimize additional piping and pumping."
d. Page 27: "Provisions for connecting to the contracted reusers will commence at the
same time as the WWTP renovation." The text goes on to detail planned reuse at
various sites in both phases I and II.
e. Page 27: "The location of these potential [reuse] sites is not known at this time."
It is necessary to know if these plans will be a functional part of this specific proposed
project. If so, their impacts and any associated mitigating measures for these impacts need to
be outlined in the EIS, especially in Sections D, E, and F.
Since it is not possible to completely evaluate this option, it is not a viable alternative.

14. It is not clear whether this project is viewed as an upgrade to the Robeson Creek WWTP or
as a completely new facility that will continue using portions of the existing facility. Please
state whether the new facility, in any stage of this project, will still be known as the Robeson
Creek WWTP.
a. Page 16: "The purpose of this population/demand growth assessment is to
emphasize the need for the expansion of the existing wastewater system to improve
current capacity and satisfy the inevitable increase in future demand."
b. Page 20: "Ultimately, a city-wide reuse distribution system will be able to receive
treated effluent from either the Robeson Creek WWTP or the new WWTP."
c. Alternative 2 on page 22 is titled "Upgrade/Expand Robeson Creek WWTP" and
Section 2.2 is titled "Expansion of Robeson Creek WWTP."
d. Page 27: "The Robeson Creek WWTP would be upgraded to produce reuse quality
water at 1.0 MGD."
e. Page 79: "The improved effluent quality of the new WWTP combined with the
upgraded existing WWTP is expected to have an acceptable minor impact on the Haw
River and Jordan Lake."
15. Page 21 states "Considering the projected growth in the Pittsboro area, and the need for
management of wastewater collection and treatment to protect Jordan Lake and Haw River
water quality, the no -action alternative will meet neither environmental nor economic needs."
It would seem that the no action alternative would focus on the impacts to Robeson Creek,
not the proposed preferred alternative of the Haw River (and Jordan Lake), as these resources
are not currently directly impacted by the discharge. Please clarify.
16. Page 21 states "The "No Action" alternative implies no increase in public wastewater
treatment capacity. Consequently, private septic systems will be the most likely
wastewater disposal method for new development after the existing 0.75 MGD
capacity is fully allocated." Also, page 80 states that expansion of the treatment
system "will deter construction of new septic systems." Are septic systems allowed
within Pittsboro? What are the capabilities of the soils within the Pittsboro/Chatham County
area to handle waste disposal with septic systems?
17. It would seem that the influent and effluent piping facilities for the expanded/new 1.0-4.0
MGD WWTP will require expansion, however this is not mentioned in the EIS. Please
explain.
18. Page 23: The discussion of NPDES limits only on the limits at 4.0 MGD. Please include
discussion of limits at 1.0 MGD.
19. Page 24: A connection to a larger POTW such as OWASA will likely require greater
control of flow rates than provided by variable -speed pumps alone. Adding flow
equalization at one or both ends of the force main would give OWASA the ability to control
the feed rate into its plant and reduce the peaks flows from the force main. At the same time,
it could reduce the necessary pumping rates — and pump sizes — required for the connection.
20. Page 57: The Division has now added the Haw River to its 303(d) list of impaired
waters. The 2006 Integrated 305(b) and 303(d) Report, recently approved by the USEPA,
lists the river as impaired due to chlorophyll a exceedances. Please amend this section of the
document to reflect the change.
21. Page 79 states "The new WWTP effluent will meet NPDES limits assigned by DWQ to
minimize impacts to water quality." Through discussions with Mike Templeton with the
DWQ Permitting Unit, it was determined that the town has been issued speculative limits at

1.2 MGD but not 1.0 MGD.
The town needs to inquire whether the 1.2 MGD limits are applicable at a 1.0 MGD
discharge.
Also, be aware that the issuance of speculative limits does not guarantee that the town will
receive these same limits for its WWTP discharge permit.
22. The discussion of the "Connection to a larger publicly owned treatment plant" alternative on
page 24 states "This alternative consists of the Town of Pittsboro constructing 1)
improvements to their existing 0.75 MGD WWTP, to enable it to consistently produce
effluent quality water for reuse and 2) facilities to pump 4.0 MGD to OWASA for treatment
and disposal."
a. If all of the effluent would be pumped to a regional facility, why would it be necessary
or financially responsible of Pittsboro to consider upgrading the existing facility to
produce higher quality effluent? Further down page 24 it states "For the 20-year
planning period, the connection to OWASA must be capable of transporting an
average daily flow of 4.0 MGD of untreated wastewater when reuse is unavailable."
Please explain.
b. The above statement is in contrast with a statement on page 25 that a pump station
"would be built at the WWTP and would pump all flow in excess of 0.75 MGD to
OWASA."
c. Page 25 states "This alternative would require the Town to make improvements in the
period 2007-2008. The existing treatment plant would have to be renovated to produce
reuse quality water for disposal at the identified reuse sites. Secondly the construction
of a pump station with the buried force main over the 16 miles would need to be
installed with its requisite EA and EAA." Again, if the regional WWTP alternative
were chosen why would the town choose to invest money in an upgraded system to
only have this higher quality effluent carried to another facility for redundant, if not
duplicate, treatment?
23. Page 25 states "The Town took bids in the fall of 2005 for a project to modify the existing
WWTP to consistently produce reuse quality effluent with the -low bid received as
approximately $3.75 million dollars. Making modifications to the existing plant is not
feasible since portions of it are 18 years old with some sections,30-plus years old.
Therefore an upgraded plant of 1.0 MGD would need to be installed adjacent to the existing
plant location. The existing influent pump station, sludge thickening facilities, sludge
storage faculties, and tertiary filters would remain in service for the new 1.0 MGD WWTP."
Why did the town take bids to modify the plant if doing so is not feasible due its age and
condition? There is further discussion of upgrading the current facility when it is stated
earlier in this . section that all 4.0 MGD would be pumped to OWASA. Please explain and/or
amend the text.
24. The discussion of the land application alternative states that for the purposes of evaluating
this alternative it is "assumed that the Town can purchase all of the required land within 4
miles of the treatment plant."
a. Why does the tract for this option need to be located within 4 miles of the WWTP?
b. How does one make this assumption on the amount of land required?
25. Page 31 states "In consideration of water quality, protected species, recreation, and
terrestrial habitat impacts combined, the (US-64) discharge site may be the location of least

overall impact." The "may" in this sentence needs to reflect that the preferred
alternative is to discharge at US-64 and that the consultant has determined that this
site will have the least impact upon receiving waters, if this is the case.
26. The Section D should primarily be focused on discussion at the selected discharge point
alternative.
27. Page 32 needs to present the elevations at the proposed plant site and along the effluent
forcemain.
28. The discussion of soil types needs to address the types that are present along the effluent
piping route. Since this will be located in ROWs, if the most appropriate answer is that the
soil types have been "disturbed," please use this description for the soil type.
29. Pages 57-62: Please update this information as needed and provide citation for the October
2005 Cape Fear River Basinwide Water Quality Plan as well as the Draft 2006 Integrated
Report, both of which can be found on the DWQ website.
30. Page 65 states "WWTP construction will require clearing approximately 8 acres of alluvial
and upland forest on the 10 acre WWTP property." Is this just for phase I or does it include
the disturbance created by phase II as well?
31. Page 75 states "Direct, secondary or cumulative construction impacts of the project include
the construction of the proposed wastewater treatment plant and the discharge forcemain
from the WWTP to US-64 bridge crossing of the Haw River."
a. Only the direct impacts of the project "include the construction of the proposed
wastewater treatment plant and the discharge forcemain from the WWTP to US-64
bridge crossing of the Haw River." (Possibly the reuse lines as well if they are
considered a part of the proposed project.)
b. Secondary impacts are effects that are caused by and result from the proposed WWTP
although they are later in time or further removed in distance, but still reasonably
foreseeable.
c. Cumulative impacts occur through two main pathways: (1) through persistent
additions or losses of the same resource(s), and (2) through the compounding effects
as a result of the coming together of two or more effects.
Please amend the text appropriately to include a complete discussion of secondary and
cumulative impacts.
32. Page 75: Please address whether and how the flood -hazard and flood prone areas mentioned
on page 32 will be impacted by the construction of the WWTP. Please also address this in
Section F.1.
33. While page 76 states that "The effluent force main will temporarily impact some prime
farmlands, but after construction agricultural use may resume," Page 39 states that "lands of
agricultural importance will not be disturbed." Please provide a statement of impacts to
prime farmlands.
34 While page 76 says that "Most of the discharge corridor length is within ROWs," page 39
states that "that discharge mains will [all] be placed in approved ROWs" and page 83 states
that "sewer lines will be constructed within the NCDOT rights -of -way." Please clarify.
35. Page 77 states "Where the forcemain crosses streams it will be installed by directional bore."
Does this include wetlands too?
36. The discussion of impacts to wetlands on page 77 should address whether the construction of
the WWTP impacts the 0.88 acre of wetlands mentioned on page 45.
37. Page 77 states "The Town of Pittsboro and Chatham County ensure that impacts on wetlands

will be avoided or minimized." Does either authority have ordinances in place that protect
wetlands, streams, or buffer areas? If so, please include them in the appendix.
38. Page 78 states that the wastewater will be "treated and sterilized at the new facilities."
Please remove the word "sterilized" and use "disinfected" instead.
39. Page 79 states "Once the Haw River discharge becomes operable, the Robeson Creek
discharge will be decommissioned." Will the 1.0 MGD be discharged to Robeson Creek or
the Haw River?
40. Page 81 states "As previously discussed in Section D.11, for the construction of the
proposed WWTP, Pittsboro will purchase approximately 10 acres of a 27-acre tract." That
the town has to purchase this tract was not mentioned previously in the text. It was implied
on page 64 that the town already owned this tract of land. Has the town acquired this
property? If not, this is another instance where the preferred alternative is not feasible at this
time.
41. Please add the word "Cumulative" to the label under Indirect Impacts in Section E.11, page
81.
42. Please divide Section E.13 on page 82 between direct and indirect and cumulative impacts as
is done in previous sections.
43. Page 83 states that the project will not have any long-term impacts on water quality. It
should be considered that the proposed project will be potentially beneficial for Robeson
Creek..
44. Page 84 states "To minimize the direct impacts that the WWTP expansion or the
construction of the forcemain discharge could have on floodplains, the project area and
sewer alignments are located outside the 100-year floodplain." However, page 75 states that
"The effluent force main and discharge structure will cross floodplains of several small
creeks." Please amend as appropriate. Also, the fact that the line will cross floodplains
should be addressed in Section D.1.
45. Page 84 states that "In order to further reduce negative impacts to floodplains, any
obstructions or collections of debris will be promptly removed at all stream crossings in order
to reduce the potential for flood hazards." Page 77 states that stream crossings will be
accomplished by directional boring. Directional boring should not create the debris
mentioned on page 84. The crossing method alluded to on page 84 is the open -cut method.
Please amend as appropriate.
Also, page 85 states that it is recommended that "The directional bore stream crossing
method should be used for utility crossings where no other reasonable technique is available .
... Stream crossings should be near perpendicular (75° to 105°) to stream flow and should be
monitored at least every three months for maintenance needs during the first 24 months of
the project and then annually thereafter." Please amend since page 77 states that this method
will be used.
46. Page 85: Second sentence of second paragraph — Please change "dykes" to "dikes." Please
make this change on page 29 as well.
47. Page 85 states that 200- and 100-foot buffers will be maintained for those streams that
contain protected species. These buffer widths should be mentioned on page 65 that states
"a minimum forest buffer width of 50 feet along Robeson Creek and 25 feet along other
property boundaries will be retained."
48. Page 87 states that "No new sewer lines or structures shall be installed or constructed in the

100-year floodplain or within 50 feet of wetlands associated with a 100-year floodplain."
However, page 75 says that the lines will cross floodplains. Please amend.
49. The document mentions several trademarked items. Per G.S. 133-3, specifying sole sources
for materials is not allowed in EAs to permit a fair bidding process for the project. Please
remove these references from the text and used generalized descriptions of the processes
instead.
50. The report should contain a topographic map overlain with all of the proposed project
components.
51. Wastewater Flow Projections
The 2006 Engineering Alternatives Analysis (EAA) prepared by Diehl & Phillips (Exhibit
D) correctly notes that the Town of Pittsboro and DWQ agreed on a 20-year flow projection
of 2.25 MGD rather than the Town's original estimate of 3.0-4.0 MGD. We arrived at this
figure based on a review of population growth rates in other rapidly growing communities of
similar size in the state. We also recognized that developments planned or underway in
surrounding Chatham County would likely mean additional flows to the Town's wastewater
treatment plant, because the County has no treatment facilities to meet that demand.
Pittsboro and Chatham County met with DWQ to explore the possibility of a regional
wastewater system, and we had limited success in identifying discharge options for the
projected regional flows. Now, Chatham County has requested speculative limits for a new
discharge of up to 19 MGD and is at least considering developing its own wastewater
treatment system rather than relying on a regional approach to meet its needs.
In light of this, the EIS should explain how the Town and the County are coordinating their
wastewater efforts in the region. It should describe any agreements and include any
delineation of service areas, plans for phased or transitional services, or other steps that will
affect the Town's flow projections.
DWQ will look critically at any proposed design flow greater than 2.25 MGD and will
expect clear justification of any added flows and consistency between the Town's and the
County's wastewater plans. Further, a significant change in the design flow from the 4.0
MGD proposed in this document will, of course, require substantial revisions in the
document and its supporting analyses to reflect the adjusted flow value.
52. Nutrient Allocations and Discharge Limits
The document rightly notes that the new treatment facilities will be designed to meet
applicable nutrient limits. However, it specifies a mix of design effluent loadings for
nitrogen and phosphorus, including the following:
Given Design Targets, lb/yr @ 4 MGD
Pages Nitrogen Phosphorus
4 36,530 6,090
(3 mg/L @ 4MGD) (0.5mg/L @ 4MGD)
8, 16 27,514 3,731
31 (Table 10) 36,203 4,550 (creek)
29,907 3,927 (river)

Transport considerations in the Jordan Reservoir nutrient strategy are most likely the cause
of this confusion. Under the strategy, Pittsboro will receive "delivered" nutrient allocations
that will cap its contributions to the reservoir. Please correct these and any other references
so that they specify a single set of nutrient design loadings.
All of these potential limits are derived from Pittsboro's allocations in the draft Jordan
Reservoir nutrient management strategy. The proposed strategy will eap the allowable
loads from each discharger. Allocations are defined as "delivered" loads, which are set so
as to restore water quality in the reservoir; and, after accounting for transport losses, the
corresponding "discharge" loads, which become the nutrient limits in each facility's
discharge permit.
In the draft strategy, Pittsboro's delivered allocations are 27,514 lb/yr TN and 3,731 lb/yr
TP. The transport factors (percent of discharge load predicted to reach the reservoir) at its
Robeson Creek discharge point are 76% for nitrogen and 82% for phosphorus, leading to
discharge allocations (and permit limits) of approximately 36,200 lb/yr TN and 4,550 lb/yr
TP. However, as the document notes, the Robeson Creek phosphorus TMDL is more
stringent and forces the Town to relocate its discharge in order to expand. With the
relocation of the outfall to the Haw River, the Town's delivered allocations do not change
but the transport factors do, as shown in Table 10, and result in a change in the discharge
limits for the new treatment plant.
It now appears that the transport factors for the new discharge point will approach or equal
100% because of location in the mainstem of the Haw River and its proximity to the
reservoir pool. The Division's Modeling & TMDL Unit is aware of the urgency of this
issue and is working now to determine what factors are appropriate for the new outfall
location.
53. Non -discharge options. The Division supports and encourages the Town's efforts to plan and
implement a variety of non -discharge programs in order to divert some portion of its treated
effluent for non -discharge beneficial uses. We also agree with statements on pages 20 and 26
that these programs are not a permanent end use and so do not reduce the design flow for the
Town's discharge to surface waters.
Please contact me at [phone], ext. 555, if I can be of any additional help in resolving
these issues. Thank you.
Cc: Alan Clark
Cyndi Karoly
Nora Deamer
Darlene Kucken
Mike Templeton
Peter Caldwell