NC0044423_NOI2021LV0818_Response_20211104

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Daniel Gryder
Lowery, Patricia
[External] ASU Water Plant NOV-2021-LV-0818
Thursday, November 4, 2021 11:19:59 AM
NOV 11-2-21.pdf
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Ms. Lowery,
I am writing to you regarding the NOV we recently received for our wastewater discharge. As
we have previously discussed, below I have outlined the steps ASU is taking to remedy the
problem.
1. ASU has implemented a new discharge schedule to avoid running the plant during a waste
water discharge. When the backwash from the plant runs into the basin, the basin water gets
stirred up. ASU is now performing discharges when the plant is not running Additionally
this will help with the copper as ASU's wastewater discharge is located in close proximity to
the intake structure. It is believed that giving the wastewater time to disperse instead of
immediately pulling it back into the intake will help keep the copper from being recycled.
2. ASU has hired Dewberry Engineers to help come up with a solution to the high copper
problem. Dewberry has assisted ASU in forming 3 valid solutions to remove the copper from
the wastewater, or to keep from concentrating the copper in the lake around the intake
structure. These solutions are outlined in the permit modification request that was sent to
DEQ in July. During a recent discussion with DEQ, ASU and Dewberry decided that further
permit modifications would be required to attain compliance. An alternate proposal for
wastewater solutions was submitted by Dewberry to ASU and was accepted by ASU.
Dewberry is set to deliver the results of the new study in approximately 5 weeks. The
resulting information will then promptly be submitted to DEQ for review.
3. ASU recently had a meeting with several members from DEQ onsite at the water treatment
plant. During the meeting DEQ suggested a change in the sampling location. ASU has now
installed a sampling port that will be more in line with DEQ's suggestion.
4. Upon receiving notice from the plant operators that turbidity would be above the limits for
the month of August, ASU took action and installed a new turbidimeter in the wastewater
settling basin. ASU also purchased a YSI data logger to continuously log the turbidity in
NTU. The meter has been recording data since October 11. Once a baseline is established, an
aeration line will be added to the basin in an attempt to decrease the water density and drop
out suspended solids. The aeration line will not be installed until after November 11. It is
believed that this combined with the new sampling location will stabilize the turbidity levels in
the basin.
5. ASU has recently hired a wastewater management company to pump and remove the CIP
backwash water from the plant. This wash cycle contains the most highly concentrated copper
and zinc. In the past, this CIP wastewater has been added to the regular plant backwash
water. ASU will no longer release the CIP wastewater into the wastewater basin as long as the
removal cost can be justified. In time, the net removal of metals from the system is expected
to help bring the copper and zinc levels into compliance.

We at the ASU Water Plant are highly committed to protecting the water quality of our basin,
and will continue to strive for excellence in all aspects of water treatment.
Please let me know if there is any other information I can provide for you.
Thanks,
Daniel Gryder