Letter Report on: The Blue Grass Chemical Agent Destruction Pilot Plant's Water Recovery System (2012)
Chapter: ATTACHMENT A STATEMENT OF TASK
ATTACHMENT A
STATEMENT OF TASK
The Blue Grass Chemical Agent Destruction Pilot Plant (BGCAPP) is being built to safely destroy the chemical weapons stockpile currently in storage at the Blue Grass Army Depot near Richmond, Kentucky. In the BGCAPP process, a water recovery system (WRS) will be used to reclaim water from supercritical water oxidation reactor (SCWO) effluent for reuse as quench water for the SCWO units.
The SCWO effluent is a salt solution with a range of 1 percent to 3 percent dissolved solids content, consisting primarily of sodium chloride, sodium sulfate, and sodium dihydrogen phosphate. The SCWO effluent also contains suspended solids consisting primarily of titanium dioxide for the nerve agent campaigns and iron oxide for the mustard campaign. The WRS includes three reverse osmosis (RO) units, two operating and one spare, and also an RO feed preparation system using filtration and antiscalant/coagulant injection to prepare the SCWO effluent for RO feed.
Each RO unit separates the permeate with 70 percent yield of the total water feed. Recovered water contains less than 500 mg/L of total dissolved solids (TDS) content and is transferred to RO permeate tanks for subsequent reuse; the RO reject stream is sent to reject tanks prior to shipment offsite for disposal.
Reverse osmosis technology has not been employed for recovery of water from plant effluent in previous chemical demilitarization operations. Because failures due to corrosion, fouling, and other mechanisms have been reported for similar RO systems, including desalinization systems installed to provide fresh water to the former Johnson Atoll Chemical Agent Disposal System (JACADS), a review by the National Research Council of the design of the BGCAPP WRS under construction at BGCAPP to identify possible issues related to operability and reliability has been requested by the Army’s Program Manager for Assembled Chemical Weapons Alternatives.
The National Research Council will establish an ad hoc committee to:
- Obtain information from the equipment vendor on water recovery system (WRS) installations that treat comparatively similar effluents to those at BGCAPP.
- Contact a representative industrial installation to review its reverse osmosis (RO) system operational and maintenance history, and determine the degree to which operability has been acceptable.
- Ascertain the likelihood that the quality of the recycled water will meet requirements for its re-use as quench water in the plant.
- Review materials of construction to determine whether adequate performance can be expected over the anticipated operational life of BGCAPP, specifically addressing potential concerns for corrosion, fouling, and stress cracking.
- Produce a letter report on determinations resulting from the above examinations.
