NC0036269_Email_20190625

Strickland, Bev
From:
Marie, Karen <[e-mail]>
Sent:
Monday, June 24, 2019 4:44 PM
To:
Basinger, Corey
Cc:
Scheller, Roberto; Fowler, Mark; Cook, Braden; Wingler, Jesse; Sims, James; Atkinson,
Cayce
Subject:
RE: [External] ORC Designation Update - Permit NCO036269 (Rocky River Regional
WWTP)
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Good afternoon Corey,
I wanted to give you an update for RRRWWTP. Process results for NH3 have improved over the course of
June. We are in currently in compliance for the weekly limit for NH3 going on 2 weeks now. We have three
violations for NH3 for the month of June: 2 weekly and 1 monthly. CBOD results are in compliance for both
weekly/monthly limits.
NH3: Week 1 and 2 we had violations of the weekly limit (10.8 mg/L). Week 3 we were in compliance
for weekly limit. Week 4 we are currently in compliance for weekly limit. Week 1 values put monthly
compliance (3.6 mg/L) out of reach even if we utilized all additional sampling days for June.
Week 1 AVG: 15.5 mg/L
Week 2 AVG: 13.9 mg/L
Week 3 AVG: 9.6 mg/L
Week 4 AVG: 10.1 mg/L currently
CBOD: No violations of weekly (23.1 mg/L) or monthly (15.4 mg/L) limits.
Week 1 AVG: 13.0 mg/L
Week 2 AVG: 11.6 mg/L
Week 3 AVG: 12.7 mg/L
Week 4 AVG: 10.1 mg/L currently
We continue to partner with Brown and Caldwell to optimize our operational controls. We have been
operating the plant in series since 06/03/19. The goal is for Step 1 biomass to absorb the toxic "hit" and
alleviate the toxic burden on Step 2. Batch reactor tests show some success with this. We've maintained SRT
set points of 5 days (Step 1) and 15+ days (Step 2) since 05/31/19. Inhibition batch reactor testing on trunk
lines with an eye toward industries has yielded some interesting results. The LRRPS trunk line inhibition has
diminished to almost no inhibition over the last three weeks. Recently, we started to see intermittent
inhibition on CWIB trunk line. We are formulating a plan for testing. We are currently running batch reactors
with a focus on plant MLSS nitrification to see if our bugs are getting stronger and to recheck inhibition within
the solids themselves.
This is some of the most recent sampling and analyses that we have done:
Metals on RR EFF, Step 2 eff, Pri eff and influent 5/21/19
Septic metals 6/5/19

LRRPS and CWIB metals 5/21/19
TKN and NOx daily on the influent and any other samples that we are interested in
Activity Tests (3-4 days per week) on trunk lines, main outfalls, influent, step I and II ML, Pri Eff, side
stream, step I eff, S&D, HCC, BFI, Perdue, etc.
Toxicity testing with ETS (treat the effluent to remove different groups of compounds and run tox) on
5/11/19
Organic analyses (VOCs and SVOCs) on main outfalls, Pri eff, Step I eff, Step II eff, side stream on
6/20/19
Cyanide analyses (2 days per week) on Pri eff, main outfalls, side stream
Conductivity (2-3 days per week) on influent, Pri eff, step 2 eff
All of these analyses have already been done at least once since our problems began.... This is round two.
Going forward, we're creating a flow diagram to get a better overall picture about what has worked and what
has not over the last 5-6 months. We will be reaching out to DWR Technical Assistance as well, a suggestion
from Roberto Scheller. We agree the more eyes on this, the better. If you have any questions, thoughts or
suggestions, please let me know. We would welcome them.
Thank you,
Karen.
xaren R. Marie
Operations Supervisor
Rocky River Regional WWTP, 6400 Breezy Lane, Concord, NC 28025
[phone], ext. 110, A [phone]
WSAQC
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