Planning & Implementation of Closure by Removal In Louisiana

Angela Harrigal, AECOM
Denise Radaich, GeoEngineers, Inc.

Description

Planning and Implementation of Closure by Removal (Clean Closure) In Louisiana Authors Ms. Angela Harrigal - United States - AECOM Ms. Denise Radaich - United States - GeoEngineers, Inc. Abstract Cleco, a Gulf Coast utility is closing their ash impoundments at the Dolet Hills Power Station located in Mansfield, Louisiana. Ash Basin No. 1, Ash Basin No. 2 and the Secondary Pond are commonly referred to collectively as “the bottom ash ponds” and are permitted under AI# 585/GD-031-1551/P-0037. This presentation will focus on some of the unique aspects of clean closure in Louisiana and provide a holistic project overview from early planning stages to challenges encountered during the ongoing pond closure. The bottom ash ponds were first permitted in 1985 under the Louisiana Department of Environmental Quality (LDEQ) solid waste regulations, updated in 1994 and 2007 by Mandatory Modifications as required by updated regulations and the revised permit was approved in 2010 and set to expire in December 2025. Cleco opted to move forward with clean closure activities. The primary inflow to the ash basins was bottom-ash laden sluice water from the ash handling system. This material is somewhat unique in that the type of coal burned at this facility was lignite coal. Other inflows into the ponds include sanitary sewage treatment plant effluent and water purification plant effluent. Solids collected in the ash basins consisted of settled ash particles. The solids are periodically dewatered, removed from the basins and either placed in the onsite landfill or transported offsite as a beneficial use material. The primary inflow into the Secondary Pond is overflow water from the two ash basins. Working with the owner and excavation contractor, many challenges have been addressed and will continue to be addressed, to achieve a safe, efficient, and cost-effective solution for compliance.

 
May 14th, 1:00 PM May 14th, 1:30 PM

Planning & Implementation of Closure by Removal In Louisiana

Grand Rapids, Michigan

Planning and Implementation of Closure by Removal (Clean Closure) In Louisiana Authors Ms. Angela Harrigal - United States - AECOM Ms. Denise Radaich - United States - GeoEngineers, Inc. Abstract Cleco, a Gulf Coast utility is closing their ash impoundments at the Dolet Hills Power Station located in Mansfield, Louisiana. Ash Basin No. 1, Ash Basin No. 2 and the Secondary Pond are commonly referred to collectively as “the bottom ash ponds” and are permitted under AI# 585/GD-031-1551/P-0037. This presentation will focus on some of the unique aspects of clean closure in Louisiana and provide a holistic project overview from early planning stages to challenges encountered during the ongoing pond closure. The bottom ash ponds were first permitted in 1985 under the Louisiana Department of Environmental Quality (LDEQ) solid waste regulations, updated in 1994 and 2007 by Mandatory Modifications as required by updated regulations and the revised permit was approved in 2010 and set to expire in December 2025. Cleco opted to move forward with clean closure activities. The primary inflow to the ash basins was bottom-ash laden sluice water from the ash handling system. This material is somewhat unique in that the type of coal burned at this facility was lignite coal. Other inflows into the ponds include sanitary sewage treatment plant effluent and water purification plant effluent. Solids collected in the ash basins consisted of settled ash particles. The solids are periodically dewatered, removed from the basins and either placed in the onsite landfill or transported offsite as a beneficial use material. The primary inflow into the Secondary Pond is overflow water from the two ash basins. Working with the owner and excavation contractor, many challenges have been addressed and will continue to be addressed, to achieve a safe, efficient, and cost-effective solution for compliance.