NCG140041_Response to NOV_20190221

February 18, 2019
Mr. Zahid S. Khan
NCDENR
610 East Center Ave, Suite 301
Mooresville, NC 28115
Dear Mr. Khan,
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I am writing you in response to the Notice of Violation received from your office dated February 5,
2019 in regards to the exceedance of pH benchmarks associated with the discharge that was sampled
from outfall #1 Concrete Supply Co — North Plant (C.O.C# 140041) on December 6, 2018 by the
CMSWS staff.
Our investigation noted that this exceedance was caused by poor housekeeping practices of the past
plant manager. The plant manager did not manage his treatment bay "clear well' properly and allowed
an overabundance of solids to accumulate. With this accumulated solids, the treatment well lost
capacity of water to be treated which reduced the ability of the treated water to lower the pH of the pond
that it was discharged to. In addition, the over abundance of solids in the treatment bay were such that
some of the solids were pumped to the pond with the treated water. Not only did the solids increase the
pH of the pond, they also reduced the operational effectiveness of the pH adjuster.
To prevent further occurrences of a high pH discharge Concrete Supply used a long arm track-ho to
remove the accumulated solids from the clear well, then a vacuum truck was brought in to remove the
excess solids from the treatment well. In addition, a policy has been instituted that the clear well must
have the accumulated solids removed once they have reached 75% of the total volume of the clear well.
The track-ho was then used to remove the accumulated solids from the pond and replace the filtration
rock in the pond. Concrete Supply temporarily closed off the lower discharge access to the concrete
riser in the on -site pond as well as instituted the recycling of process water back into our concrete
production as a means of reducing the overall volume of process water that enters into our process water
system. In addition, the plant staff removed over 60,OOOgalons of process water from the discharge
pond, treated it to a pH of 6, and slowly re -introduced the water back into the pond to help lower the pH
of the pond. The manufacturer of the pH adjustment system was contacted and they repaired the on -site
pH adjuster to proper working order.
Please understand that we are determined to prevent this type of situation from arising again. We feel
that this can be accomplished with better training, communication, and follow up with our staff.
Si rely,
Jo nie Ale ander
Environmental Manager
Concrete Supply Co.
Office: 704-372-2930

Compliance Inspection Report
Permit: NCG140041 Effective: 08/01/17 Expiration: 06/30/22 Owner: Concrete Supply Co LLC
SOC: Effective: Expiration: Facility: Concrete Supply Co-N Plant
County: Mecklenburg 3823 Raleigh St
Region: Mooresville
Charlotte NC 28206
Contact Person: Johnie Alexander Title: Phone: [phone] Ext.2071
Directions to Facility:
System Classifications:
Primary ORC:
Secondary ORC(s):
On -Site Representative(s):
Related Permits:
Inspection Date: 02/26/2019
Primary Inspector: James D Moore
Secondary Inspector(s):
Certification: Phone:
Entry Time: 03:15PM Exit Time: 03:30PM
Phone:
Reason for Inspection: Follow-up Inspection Type: Compliance Evaluation
Permit Inspection Type: Ready Mix Concrete StormwaterfWastewater Discharge COC
Facility Status: ❑ Compliant ❑ Not Compliant
Question Areas:
Storm Water
See attachment summary)
Page: 1

Permit: NCG140041 Owner - Facility: Concrete Supply Co LLC
Inspection Date: 02/26/2019 Inspection Type : Compliance Evaluation Reason for Visit: Follow-up
Inspection Summary:
The inspection was a follow-up regarding the January 31, 2019 NOV. Based on the inspection housekeeping has improved
and waste solids have been removed from the site.A follow-up compliance inspection should be conducted by March 26,
2019.
Page: 2

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