Recent research has demonstrated the potential to transform chicken hatchery waste, predominantly eggshells, from environmental burden to valuable bio-calcium oxide (bio-CaO) through thermal decomposition. Conducted at a laboratory-scale rotary kiln, this innovative approach not only addresses waste management issues associated with hatchery solid waste but also contributes to sustainable development.
Calcium oxide, widely known as quicklime, plays numerous roles across various sectors from industrial catalysts to food additives. Traditional quicklime production methods are not only resource-intensive but also significantly contribute to carbon dioxide emissions, accounting for about 8% of global anthropogenic CO2 emissions. The switch to bio-CaO derived from renewable resources presents a feasible solution to reduce these environmental impacts.
The experiments involved separating eggshells from the mixed solid hatchery waste, which consists of materials such as dead embryos and liquid from decaying tissue. Various factors affecting the production of bio-CaO were explored, particularly focusing on preparation methods, including the handling of eggshell membranes, particle size, and the operational settings of the rotary kiln.
This study employed calcination techniques at 800 °C within the rotary kiln, known for its enhanced mixing and heat transfer capabilities compared to more traditional batch processing methods. The results indicated optimal yields of bio-CaO, with production rates ranging between 49% to 56% and purity levels within 97% to 98%. Notably, maintaining larger particle sizes significantly increased production yields, illustrating the importance of raw material handling.
Researchers emphasized the advantages of rotary kilns, which allow for skilled manipulation of operational parameters, including rotation speed and atmosphere (air versus nitrogen). Their findings revealed the purification and output quality of bio-CaO was consistently high with minimal adjustments needed to the existing setup.
One of the key revelations from the study is the feasibility of scaling up the process to meet industrial demands, supported by the compliance of produced bio-CaO with local industrial and international food additive standards. This promising technique not only highlights the potential for circular economy practices within the industry but also opens pathways for reducing reliance on non-renewable resources.
The project was significantly backed by Thailand Science Research and Innovation (TSRI) where researchers acknowledged collaboration among various institutions. The outcomes pave the way for not only cost-effective quicklime production but also contribute to minimizing waste disposal concerns faced by the hatchery industry.
Conclusively, the thermal decomposition process of hatchery waste using rotary kiln technology heralds new approaches toward sustainable resource management. Future investigations will be necessary to refine these methods for various industrial applications, ensuring ecological benefits alongside economic viability.