Final Decision to Certify Hazardous Waste Environmental Technology
The Turner Designs TD-4100 fluorometer is intended for the continuous monitoring in the field or in industrial environments of aqueous streams containing petroleum fuels or other petroleum-derived pollutants. It allows automatic out-of-control alarms or signaling to shut down the monitored flow. The technology is based on the principle of fluorescence detection in an aqueous stream irradiated with ultraviolet light. The filtered excitation light enters a non-contact, non-fouling measurement cell containing a continuous-flow, laminar, free-falling aqueous stream. The raw signal is converted into readable units, displayed on an LCD screen as either fluorescence or concentration, or into a signal suitable as input to a data logger. The compounds responsible for the signal are aromatic hydrocarbons of molecular weights ranging from benzene to polynuclear aromatics.
The TD-4100 is semi-quantitative in that it detects petroleum-derived products and pollutants in terms of a preset fluorescence level or in terms of levels set by calibration with benzene, gasoline, diesel, or crude petroleum. Detection levels in clean water are 60 ppb for benzene and 5 ppb for diesel fuel or gasoline. In ambient and industrial waters, detection levels of 50 to 200 ppb are more typical. The dynamic range typically extends over three orders of magnitude.
A critical element of the technology is the manufacturer’s commitment to match light source, excitation and fluorescence filters to a user’s needs in terms of type of product to be detected, level of detection, and type and level of site-specific interfering compounds (including interfering chemicals, changes in turbidity, or fluorescing particles such as algae), and establishment of an expected level of on-site performance based on these evaluations and prior to sale and installation of the equipment.
The variability of the background and composition of the hydrocarbons being monitored will affect the sensitivity, accuracy, and precision of measurements. In cases where the results are to be reported as the concentration of a specific analyte, the user should calibrate the instrument using that analyte, and confirmatory testing obtained using applicable U.S. EPA test methods.
Recommended applications include preventing contamination of receiving waters with oily industrial effluents and stormwater, and similar pollution of surface drinking water sources and groundwater. In most situations, and subject to those determinations which Turner Designs carries out in cooperation with each prospective user, the TD-4100 allows monitoring at or below regulatory levels.
Turner Designs, Inc.,
845 West Maude Avenue,
Sunnyvale, CA 94086
Mark D. Uhrich
(408 749-0998 (fax)
May 5, 1997
May 5, 2000
Dr. G. Wolfgang Fuhs
File last updated: May 21, 1997