Application of Near-Infrared Spectroscopy for Monitoring and/or Control of Composting Processes

Abstract

The implementation of a suitable and ecologically friendly solid waste management plan is accepted as an essential need. Given that organic matter constitutes the majority of solid waste, composting has gained popularity as an alternative way of organic refuse recycling. Compost quality is defined by its stability and maturity, both of which must be assessed by measuring a large number of physical–chemical parameters, microbiological variables, and enzymatic activities. These procedures are complex and time-consuming, making it difficult to assess compost quality correctly. Spectroscopy methods could be used as an efficient alternative. In this work, general information about composting processes and near-infrared spectroscopy (NIRS) is given. A discussion and comparison of the different approaches of coupling NIRS and chemometric tools for the monitoring and/or control of composting processes are presented in this work.

Grape Skin Composting Process to Recycle Food Waste: Kinetics and Optimization

“…Additionally, water is used by microbes to move nutrients and energy components across their cell membranes [51]. At the beginning of the processes, the moisture content was between 50-62% which is in accordance with the optimal moisture content for the composting process [30,58]. Furthermore, the appropriate level of moisture fluctuates and is contingent upon the composting material due to the unique physical, chemical, and biological characteristics of the materials [51].…”

“…There is a large variety of currently available compost systems, and they fall into two primary types: open systems, such as windrows and piles, and closed systems, such as reactors and composters [ 30 ]. Open systems require manually or mechanically turning the pile to provide sufficient oxygen supply for microbial degradation of organic matter.…”

“…The main advantages of this system are low cost and simple operation, but on the other hand, it is difficult to control the process variables which makes the composting time longer. The closed systems have advantages over the open ones: they take less space and provide better control of the process, which leads to high efficiency of the process [ 30 , 31 ].…”

Assessing Digestate at Different Stabilization Stages: Application of Thermal Analysis and FTIR Spectroscopy

“…Spectroscopic analysis aids in understanding changes in organic material suffered during microbial degradation. This technique has provided useful information when evaluating the composting of lignocellulosic material and wastes [56][57][58] and studying the digestion process of different substrates [8,[59][60][61]. Figure 6 shows the spectra obtained from the feed and digested samples.…”