A Low Cost UV Raman Insturment Measuring Nitrate and Nitrite for Impoved Operation and Control of Nitrification/Denitrification Treatment Processes

We propose to develop a unique, on-line, in situ autonomous monitoring and process control system that will improve the reliability and performance of wastewater treatment systems that are designed to remove nitrogen through simultaneous nitrification and denitrification (SNdN). A key component technology of the proposed innovative process control system will be an analytical insturment based on deep untraviolet resonance Raman (UVRR) spectroscopy which will measure nitrate and nitrite concentrations in BNR system reactors without the need for sample handling, reagent additions or complex calibration procedures. Detection limits for the proposed insturment are expected to be below about 2 ppb for nitrates and nitrites. Deep ultraviolet resonance Raman spectroscopy, appropriate to nitrate and nitrate samples, has several advantages over normal Raman spectroscopy. First, excitation at 224nm provides about 150 times signal enhancement over normal Raman spectroscopy conducet at 785nm. Second, when excitation occurs within an electronic absorption band of the target material, a resonance effect provides up to eight orders of magnitude of additoinal signal enhancement. The third major advantage of excitation in the deep ultraviolet is the elimination of background fluorescence from samples of complex, composite, materials since no materials are know to fluoresce a wavelenghts less than about 270nm whereas all ot the Raman spectral information from a 224nm excitation occures at wavelengths less than 245nm. The porposed instrument uses a unique deep UV laser technology, with 224nm emission wavelength, and subminiature Raman analysis detectio methods to make a very inexpensive, minature (<4 liters), light weight (<5 pound), low power consumption (<5 watts) instrument that can be used, in situ, or autonomous measurements in harsh environments. The size, weight, and power consumption specificaitons are for the complete instrument including laser, detectors and all pwer supplies and controllers. The important commercial applications of this new technology include: in situ monitoring and control of small decentralized membrane bioreactor (BMR) satellite wastewater treatment systems producing reclaimed water for local reuse; retrofitting existing wastewater-treatment plant process control systems to improved energy efficiency and treatment efficiency; and cost effective and energy efficient treatment of high nitrogen contanining side streams in wastewater treatment palnts such as digester supernatant and centrate or filtrate. The proposed instument technology is also valuable for in situ, autonomous, environmental monitoring of air, water and soil as well as a wide range of commercial, industrial and medical applications.