16 Wooden Material and Environmental Sciences
373
They regarded this result, indicating that NIR analysis might become a valuable
complementary tool to traditional sediment characterization.
16.5 Wastewater
Because the advantage of NIRS including the optical path length can be longer and no
reagent is required for such measurement, some researches attempt to build accurate
calibration models for the estimation of some pollution degrees in wastewater (i.e.,
sewage, wastewater from sugar refinery processing, and black liquor). Ding et al.
[62] reported the accurate prediction model for the mixture samples tributyl phosphate and methyl iso-butyl ketone in aqueous solutions over the concentration range
of 1 ± 160 ppm with SEP for MIBK of 3.82 ppm. They used the C–H combination
bands in the range of 5000–4000 cm
−1 measured in transmittance mode (2 mm path
length) with a spectrometer equipped with the liquid nitrogen cooled InSb detector.
Pan et al. [63] showed NIRS could be used for the prediction of chemical oxygen
demand (COD) in sugar refinery wastewater with validation SEP of 25.0 mg L
−1
using transmittance absorbance spectra (2 mm path length) in the range of 780–
1100 nm. The COD is an indicative measure of the amount of oxygen that can be
consumed by reactions in a measured solution. They optimized the wavelength for
the prediction by MWPLS. Quintelas et al. [64] investigated the feasibility of NIR
transmittance spectroscopy for the quantification of pollutants, like pharmaceuticals,
in wastewater. Two hundred seventy-six samples obtained from an activated sludge
wastewater treatment process were analyzed in the range of 200–14,000 cm
−1 (transmittance mode, 0.7 mm pathlength). They obtained an adequate calibration curve
for the prediction of ibuprofen, sulfamethoxazole, 17β-estradiol, and carbamazepine
with coefficients of determination around 0.95. Lindgrerz et al. [65] reported it is
possible to monitor the delignification process during a laboratory Kraft cook on
softwood by NIR transmission measurement of the black liquor. They showed a
good calibration result for Klason lignin content in the pulps and pulp yield. Some
researchers conducted to monitor the pollution degree which was reported [66–68].
The COD values in wastewater samples collected in wastewater treatment plants were
well predicted [66] with an RMSEP value of 19 mgO 2 L
−1 . Many organic matter
index [68] and volatile fatty acids, bicarbonate alkalinity, and total and volatile solids
content [67] were also predicted from NIR spectra of sewage sludge.
16.6 Atmospheric Gas Detection
The development of effective gas detectors is essential because many gases can
be harmful to humans or animals. NIR-tunable diode laser spectroscopy has the
potential for the development of effective and inexpensive detectors for moni-
373
They regarded this result, indicating that NIR analysis might become a valuable
complementary tool to traditional sediment characterization.
16.5 Wastewater
Because the advantage of NIRS including the optical path length can be longer and no
reagent is required for such measurement, some researches attempt to build accurate
calibration models for the estimation of some pollution degrees in wastewater (i.e.,
sewage, wastewater from sugar refinery processing, and black liquor). Ding et al.
[62] reported the accurate prediction model for the mixture samples tributyl phosphate and methyl iso-butyl ketone in aqueous solutions over the concentration range
of 1 ± 160 ppm with SEP for MIBK of 3.82 ppm. They used the C–H combination
bands in the range of 5000–4000 cm
−1 measured in transmittance mode (2 mm path
length) with a spectrometer equipped with the liquid nitrogen cooled InSb detector.
Pan et al. [63] showed NIRS could be used for the prediction of chemical oxygen
demand (COD) in sugar refinery wastewater with validation SEP of 25.0 mg L
−1
using transmittance absorbance spectra (2 mm path length) in the range of 780–
1100 nm. The COD is an indicative measure of the amount of oxygen that can be
consumed by reactions in a measured solution. They optimized the wavelength for
the prediction by MWPLS. Quintelas et al. [64] investigated the feasibility of NIR
transmittance spectroscopy for the quantification of pollutants, like pharmaceuticals,
in wastewater. Two hundred seventy-six samples obtained from an activated sludge
wastewater treatment process were analyzed in the range of 200–14,000 cm
−1 (transmittance mode, 0.7 mm pathlength). They obtained an adequate calibration curve
for the prediction of ibuprofen, sulfamethoxazole, 17β-estradiol, and carbamazepine
with coefficients of determination around 0.95. Lindgrerz et al. [65] reported it is
possible to monitor the delignification process during a laboratory Kraft cook on
softwood by NIR transmission measurement of the black liquor. They showed a
good calibration result for Klason lignin content in the pulps and pulp yield. Some
researchers conducted to monitor the pollution degree which was reported [66–68].
The COD values in wastewater samples collected in wastewater treatment plants were
well predicted [66] with an RMSEP value of 19 mgO 2 L
−1 . Many organic matter
index [68] and volatile fatty acids, bicarbonate alkalinity, and total and volatile solids
content [67] were also predicted from NIR spectra of sewage sludge.
16.6 Atmospheric Gas Detection
The development of effective gas detectors is essential because many gases can
be harmful to humans or animals. NIR-tunable diode laser spectroscopy has the
potential for the development of effective and inexpensive detectors for moni-