Characterization of the biosolids composting process by hyperspectral analysis

Area of Science:

• Environmental Science
• Soil Science
• Analytical Chemistry

Background:

• Composted biosolids enhance soil quality, but immature compost can be detrimental.
• Current compost maturation assessments are time-consuming and site-infeasible.
• Hyperspectral spectroscopy shows promise for rapid compost quality evaluation.

Purpose of the Study:

• To characterize biosolid composting using hyperspectral analysis.
• To correlate spectral data with chemical properties of wet and dry samples.
• To assess the feasibility of hyperspectral analysis for compost maturity determination.

Main Methods:

• Utilized hyperspectral reflectance spectroscopy (400-2400nm).
• Employed partial least squares-regression (PLS-R) modeling.
• Correlated spectral data with chemical properties of wet and oven-dried biosolid samples.

Main Results:

• PLS-R models accurately predicted total carbon, dissolved organic carbon, total nitrogen, dissolved nitrogen, nitrate, E2/E3 ratio, and C/N ratio.
• Ammonium content was not accurately predicted in dry samples due to evaporation.
• Spectral analysis of wet samples proved effective for predicting compost maturity.

Conclusions:

• Hyperspectral analysis is a reliable tool for evaluating biosolid compost maturity and stability.
• The method is applicable to both wet and dry biosolid samples, with wet sample analysis being a viable alternative.
• This technique offers a significant advancement over traditional, time-intensive compost assessment methods.