### MEMORANDUM

FROM: Keith Barnett, US EPA

TO: Portland Cement NESHAP Docket

SUBJECT: Summary of Responses to Request s for Water Impacts Information. August 5, 2010.

DATE: August 5, 2010

"Matz, Tim" <tmatz@htcnam.com> 03/03/2009 10:10 AM To Keith Barnett/RTP/USEPA/US@EPA, "meg.garakani@holcim.com" <meg.garakani@holcim.com>, "Joel.Bolduc@holcim.com" <Joel.Bolduc@holcim.com>, "HECTOR.YBANEZ@holcim.com" <HECTOR.YBANEZ@holcim.com>, "ngarnett@txi.com" <ngarnett@txi.com>

cc Susan Thorneloe/RTP/USEPA/US@EPA, Michael Laney <mnl@rti.org>, "marvin@rti.org" <marvin@rti.org>
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Subject
RE: Wet scrubber water treatment

History: This message has been forwarded.

Keith,

Lehigh's Mason City plant's wet scrubber is a closed loop water system. The scrubber blowdown is sent to a dewatering system where the gypsum is recovered, stored and used in the finish mills. The plant still needs to purchase gypsum as the scrubber system does not provide enough for operations. The water from the dewatering system is then sent directly back to the scrubber with no further treatment. No liquid waste stream leaves the process.

Timothy L. Matz Corporate Director of Environmental Affairs

Lehigh Hanson 8505 Freeport Parkway Irving, Texas 75063 phone: (469) 417-1361 cell: (610) 554-8942 fax: (469) 417-1479
tmatz@htcnam.comHector.Ybanez@holcim.com 03/02/2009 03:00 PM To Barnett.Keith@epamail.epa.gov

cc Joel.Bolduc@holcim.com, marvin@rti.org, meg.garakani@holcim.com, "Michael Laney" <mnl@rti.org>, ngarnett@txi.com, Thorneloe.Susan@epamail.epa.gov, tmatz@htcnam.com, giri.bhavani@holcim.com
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Subject
Re: Wet scrubber water treatment

History: This message has been replied to and forwarded.

Keith

You are correct; gypsum is recovered from the scrubber by sending the material to a dewatering facility where the gypsum is dewatered and stored until it is consumed in the finish mill. This is a continuous process. The water is returned back to the wet scrubber.

Additionally, the scrubber is equipped with a storage reservoir. This is

a non-continuous process; however, when the need arises to bled-down the reservoir water is consumed by either of the two following methods: (i) Water from the reservoir is routed to a storage tank where it is stored till it is consumed as process water. This is the case for Portland. (ii) At Midlothian, the water from the reservoir is routed to a clay-lined pond where it is stored until it is consumed as process water. There is no discharge from this clay-lined pond.

If you have nay questions please let me know.

_____________________

Hector Ybanez Corporate Manager, Environmental 122 West Carpenter Freeway Suite 485 Irving, Texas 75039 Phone (214) 524 - 2814 Cell (972) 268-1139 Hector.Ybanez@holcim.com

"Garnett, Nancy" <ngarnett@txi.com> 03/02/2009 02:28 PM To Keith Barnett/RTP/USEPA/US@EPA

cc Susan Thorneloe/RTP/USEPA/US@EPA, "Michael Laney" <mnl@rti.org>,<marvin@rti.org>
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Subject
RE: Wet scrubber water treatment

History: This message has been replied to.

Keith, At TXI Midlothian - the water from the dewatering system is returned to the wet scrubber. It is not treated. The liquid that is purged from the scrubber system is not treated either. It is used to pug the alkali bypass dust or it can be used to control dust in the quarry ABD storage area. Nancy

-----Original Message----- From: Barnett.Keith@epamail.epa.gov [mailto:Barnett.Keith@epamail.epa.gov] Sent: Monday, March 02, 2009 11:53 AM To: meg.garakani@holcim.com; Joel.Bolduc@holcim.com; HECTOR.YBANEZ@holcim.com; tmatz@htcnam.com; Garnett, Nancy Cc: Thorneloe.Susan@epamail.epa.gov; Michael Laney; marvin@rti.org Subject: Wet scrubber water treatment

To All:

A question has come up about treatment of water from kilns that use wet scrubbers for SO2 control. In our analysis we assume that the scrubber blow-down is sent to a dewatering facility where the gypsum is dewatered and stored prior to being sent to the finish mill. The water from the dewatering step is assumed to be sent back to the wet scrubber.

Is there some type of water treatment process that takes place after the solids are removed from the scrubber blowdown? Or is the water simply sent directly back to the scrubber? Is there any liquid waste stream that leaves the scrubber process? If so, how is this stream treated and where does it go?

Keith W. Barnett USEPA/OAQPS/SPPD/MMG Mail Code D243-02 Research Triangle Park, NC 27711
919-541-5605