Near infrared spectroscopy for fast characterization of animal by products feedstocks for biogas production: Calibration of a handheld device

Abstract

Anaerobic digestion performance is highly influenced by the chemical composition and flow of substrates. This work evaluates the feasibility of a handheld near infrared spectrometer to predict moisture, fat, and protein content of animal by-products (ABP) mixtures further used as substrates for biogas production. The performance of a commercially handheld near infrared spectrometer (NIR) was evaluated for acquiring spectra of ABP sterilised mixtures, that were also chemically analysed. The calibration was performed by partial least square's regression technique and tested by an independent set of data. The results showed determination coefficients values ranging from 0.72 to 0.79 and root mean square errors of 2.60–4.85%. The performance of the handheld NIR spectrometer device was compared with a benchtop NIR spectrometer with a broader range of wavelength. The results suggest that NIR technology could be included as a useful estimation tool for the rapid characterization of feedstocks in biogas plants.