Addition of Boiler Charcoal Waste to Compost for Use as Substrate for Vegetable Seedlings

Abstract

The recovery of waste from the broiler production chain (BPC) is consistent with the principles of a circular economy. Besides turning waste into organic compost, its use as substrate for the production of vegetable seedlings further increases its economic value. However, it is necessary to adapt its characteristics to enable its use as substrate. To this end, the addition of boiler remnant charcoal wastes (BCW), another type of waste generated in the BPC, to the organic compost resulting from the composting of BPC waste with different bulking agents (BAs) was studied. The addition of BCW to agro-industrial compost reduced the electrical conductivity (EC) of substrates. Multiple linear regression showed that, of the 13 variables (physical, chemical and physicochemical) studied, three (EC, pH and N content) are sufficient to explain the seedling quality index (SQI). Simple nonlinear regression showed that, in order to achieve higher SQIs and easier removal of clod from tray, an additional 30% in weight of BCW is required for compost, using urban tree pruning, wood sawdust and sugarcane bagasse BAs. The use of cotton and Napier grass waste as BAs is not recommended for BPC waste mixtures, as they cause a large increase in substrate EC.

Spectroscopic and Physicochemical Characterization of Poultry Waste-Based Composts and Charcoal–Compost Mixtures for the Prediction of Dry Matter Yield of Giant of Italy Parsley

“…Conversely, high H LIF values were associated with a high concentration of aromatic groups in the amendments, compared with initial TOC, i.e., a higher degree of humification for SA and BA amendments. Interestingly, the addition of charcoal to the composts caused a reduction in H LIF value (Figure 2b), an indication that charcoal diluted the polyphenols and reduced the aromaticity of the composts [22,35], thereby reducing the degree of humification of the organic amendments. The results suggest that addition of charcoal to composts cannot be considered a method to enhance humification.…”

“…For example, some agro-industrial wastes show excessively high levels of N accumulated during the composting process [21]. Composts with excessive amounts of N must be diluted with other materials to make them suitable for use as a growth medium by preventing any possible toxic effects [22]. Additionally, growth medium components must be stable and contribute to improve not only the chemical, but the physical characteristics of the soil as well.…”

“…However, production costs for biochar and other components must be systematically assessed and compared with peat, as recommended by Haeldermans et al [30], who evaluated the techno-economic viability of biochar production. Charcoal waste resulting from the incomplete burning of wood in furnaces for heating water for industrial boilers in poultry processing plants reportedly has similar properties to biochar and peat, and might be used to produce desirable organic amendments [22]. While evaluating different organic amendments obtained by adding charcoal to composted organic wastes for the production of lettuce seedlings, Lorin et al [22] found that charcoal enhanced both the physical and chemical characteristics of the growing substrates.…”

“…Charcoal waste resulting from the incomplete burning of wood in furnaces for heating water for industrial boilers in poultry processing plants reportedly has similar properties to biochar and peat, and might be used to produce desirable organic amendments [22]. While evaluating different organic amendments obtained by adding charcoal to composted organic wastes for the production of lettuce seedlings, Lorin et al [22] found that charcoal enhanced both the physical and chemical characteristics of the growing substrates. Additionally, charcoal waste from the poultry industry is presumably physically, chemically, and structurally stable over time.…”