NC0087840_Fact Sheet_20180614

DEQ / DWR / NPDES
EXPIDITED FACT SHEET FOR PERMIT RENEWEL
PERMIT NCO087840
BACKGROUND
The Town of Middlesex operates a designed -rate 0.133 MGD potable -water treatment plant to
serve its surrounding community. Currently operated by Envirolink, Inc., the WTP applies
greensand filtration technology generating a filer -backwash averaging 0.005 MGD [for —15
minutes, one day per week]. Backwash wastes are permitted as required of a discharge to an
unnamed tributary (UT) to Turkey Creek, a waterbody currently classified C; NSW within the
Neuse River Basin. It is however noteworthy that the effluent travels via culverts, and a system
of unlined ditches (providing subsurface infiltration) such that the effluent seldom, if ever,
reaches the unnamed tributary (RRO Inspection Staff Report, 2013).
PERMITTING HISTORY
2008 — Renewal permit issued with no changes to the previous permit [Greensand Filter 2004
WTP Strategy limiting Flow, TSS, TRC, and pH].
2013 — Applied 2009 WTP Strategy for Greensand filter technology and BPJ:
• flow limit removed; monitoring changed to 2/month; footnote added;
• corrected outfall location; IWC corrected to 100%;
• fluoride and zinc monitoring removed (neither used by the [Permittee);
• iron and manganese - reduced monitoring to Quarterly
• added Turbidity monitoring, 2/month (EPA requirement);
• per Neuse River 2013 Nutrient Guidelines, semi-annual monitoring required
for nutrients as Total Nitrogen (TN) and Total Phosphorus (TP)
• TN requires Total Kjeldahl Nitrogen (TKN) plus Nitrate and Nitrite Nitrogen.
Fact Sheet — Jun2018
NPDES NCO087840
Page 1 of 2
Facility Information
Applicant/Facility
Name:
Town of Middlesex - Middlesex Well No.4 WTP
Applicant Address:
Town of Middlesex; P.O. Box 69; Middlesex, NC 27557
Facility Address:
10921 East Finch Street; Middlesex, NC 27557
Permitted Flow:
Maximum monthly average 0.0034 MGD not limited
Type of Waste:
Treated backwash wastewater from sand filters
Facili •/Permit Status:
Class I /Active; Renewal
County:
Nash Countv
Miscellaneous
Receivin Stream:
UT to Turkev Creek
Stream Class:
C, NSW
Subbasin:
03-04-07
Stream Index No:
27-86-3-(l)
Drainage Area (mi):
HUC:
03020203
Summer 2Q 10 (cfs)
303(d) Listed?
No
Winter 7Q 10 cfs :
Regional Office:
Raleigh
30Q2 (cfs):
State Grid /
USGS Quad:
D26SW /
Middlesex, NC
Average Flow cfs):
Permit Writer:
Joe R. CoMoron, LG
IWC %): 1
100% I
Date:
10un2018
BACKGROUND
The Town of Middlesex operates a designed -rate 0.133 MGD potable -water treatment plant to
serve its surrounding community. Currently operated by Envirolink, Inc., the WTP applies
greensand filtration technology generating a filer -backwash averaging 0.005 MGD [for —15
minutes, one day per week]. Backwash wastes are permitted as required of a discharge to an
unnamed tributary (UT) to Turkey Creek, a waterbody currently classified C; NSW within the
Neuse River Basin. It is however noteworthy that the effluent travels via culverts, and a system
of unlined ditches (providing subsurface infiltration) such that the effluent seldom, if ever,
reaches the unnamed tributary (RRO Inspection Staff Report, 2013).
PERMITTING HISTORY
2008 — Renewal permit issued with no changes to the previous permit [Greensand Filter 2004
WTP Strategy limiting Flow, TSS, TRC, and pH].
2013 — Applied 2009 WTP Strategy for Greensand filter technology and BPJ:
• flow limit removed; monitoring changed to 2/month; footnote added;
• corrected outfall location; IWC corrected to 100%;
• fluoride and zinc monitoring removed (neither used by the [Permittee);
• iron and manganese - reduced monitoring to Quarterly
• added Turbidity monitoring, 2/month (EPA requirement);
• per Neuse River 2013 Nutrient Guidelines, semi-annual monitoring required
for nutrients as Total Nitrogen (TN) and Total Phosphorus (TP)
• TN requires Total Kjeldahl Nitrogen (TKN) plus Nitrate and Nitrite Nitrogen.
Fact Sheet — Jun2018
NPDES NCO087840
Page 1 of 2

COMPLIANCE
Since 2014 there were two (2) monitoring frequency violations: one late DMR (May2016) and
one TN, semiannually (resolved jun2016); no action BPJ; and one limit violation [TSS Dec2017,
2% over, no action BPJ - no penalties assessed.
CURRENT TREATMENT PROCESSES
1. Well water is chlorinated then introduced to two greensand filter units.
2. filtered water continues through an air stripper
3. then pumped into the potable water distribution system
4. operator manually backwashes/rinses each sand filter as needed (once per week, typ.)
5. process backwash/rinsate passes through a meter, sand filter beds, tablet dechlorinator
6. wastewater discharged into a UT to Turkey Creek.
Permittee determines when to remove solids based on the accumulation in drying beds; removal
and disposal by licensed contractor, per state regulations.
PERMITTING STRATEGY -- RATIONALE FOR 2018 RENEWAL
The following will be incorporated into the permit.
1. Updated site map and narrative for Supplement to Permit Cover Sheet.
2. Discontinued monitoring for Total Iron [no standard/no longer a
parameter of concern (POC)].
3. Continued quarterly monitoring for Total Manganese as required for
greensand, but not limited, per WTP strategy [not discharging to WS waters];
4. Total Hardness [for calculating dissolved fraction limits] — Because
manganese cannot be limited (limit applies only to WS), and because
manganese is the only remaining metal POC, Total Hardness monitoring
(U&E) is not required;
5. Current Neuse River Guidelines classify this facility as non -nitrogen
producing; however, TN/TP semi-annually monitoring remains in the
permit per strategy; no changes recommended.
6. Because TN/TP monitoring is required [class NSW], this facility is not
elig.1ble for WTP General Permit NCG590000.
PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice: June 27, 2018
Permit Scheduled to Issue:
August 1, 2018 [estimated]
NPDES DIVISION C NTACT
If you have questions egard' g the above or the attached permit, please contact Joe R.
Corporon, LG at 11 jo [e-mail] or call my direct line [phone].
(i
NAME: ! DATE:�J�y�"
Fact Sheet — Jun2018
NPDES NC0087840
Page 2 of 2

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