SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

train as backup is not usually warred for removal of Each of these optioohave positives and negatives VOCs or metals. The components of these treatment associated with them, and these are summarized in trains require minimal downtime, and because ground Exhibit 8. Site managers should regularly evaluate water moves slowly,maintaining and operating parallel discharge options to determine which is most cost systems to prevent a few days of downtime per year is effective and should consider capital, negotiation, and not cost-effective. If one train of an operational sampling costs of the options in this evaluation. parallel system can treat the extracted water, managers should consider bypassing or eliminating the other train Disposal of filter cake from biotreatment or metals if savings from labor and maintenance are expected to precipitation can generally be disposed of as non- exceed the capital cost of the modification. hazardous waste if it passes Toxicity Characteristic Leaching Procedure (TCLP)testing. This costs less Consider Alternate Discharge/Disposal Options than disposal at a hazardous waste facility. If these materials are considered "listed"waste because of past The following discharge options are typically available site use,but the wastes pass TCLP testing,then "de- for treated water: listing" should be pursued. Savings of up to $200 per ton could result from a change in disposal practices. • publicly owned treatment works (POTWs) For some sites,this could translate to savings of up to $4,000 per month in costs associated with • storm sewer and surface water(both regulated transportation and disposal of such wastes. under National or State Pollutant Discharge Elimination System,NPDES or SPDES, Identify Onoortunities for System Automation programs) Common treatment components such as air strippers • reinjection to the subsurface(regulated by and GAC units, when properly designed and installed, Underground Injection Control Program) have been proven reliable through years of testing in the field. As a result,when these systems are installed with alarms,auto shut-offs for high levels,and auto- Exhibit 8 Discharge Alternatives for Water from a PST System Discharge alternative Positives Negatives Publicly-owned treatment require relatively flexible discharge may refuse to accept treated or works(POTWs) standards compared to other alternatives untreated ground water due to dilution (typically 2.13 mg/L total toxic or lack of capacity organics) require payment(approximately accept and treat some hard to treat $0.002 to$0.03 per gallon) contaminants (ketones and ammonia) often require pretreatment Storm sewer and surface typically do not require payment for resource conservation,some areas water often readily accessible from treatment do not allow discharge of ground water plant to surface water minimal capital costs discharge criteria is generally stringent (e.g.,MCLS for naturally occurring inorganics) lengthy permitting process frequent sampling requirements Reinjection to subsurface may help with hydraulic control of may hinder hydraulic control of plume (reinjection wells or plume may require substantial capital cost infiltration galleries) relatively easier permitting process potential issues with fouling of wells biotoxicity testing not required requires space for wells or galleries 15