Sustainable substrates to enhance nutrient delivery in urban farming

• Main Author: Tang, Yingtong
• Other Authors: Ng Kee Woei
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering
• Online Access: https://hdl.handle.net/10356/176002
• Institution: Nanyang Technological University

Plastic pollution has become one of the most critical issues threatening our environment. This problem has skyrocketed research into eco-friendly alternatives, one of which being sustainable keratin substrates developed in NTU for hydroponic urban farming usage. It has been developed as a sustainable alternative to existing farming sponges made from non-biodegradable materials such as phenolic foam, rockwool, etc. Building upon this initial novel keratin substrate, this study will drive the research further by testing the substrate in growing conditions closer to that of existing commercial urban farms. Additionally, this study intents examine the effects of autoclave and freeze-thaw cycles, in the preparation of the substrate, so as to investigate whether they influence stability of the sample. These two factors were chosen due their ability to improving bonding and cross-linking within keratin, as shown in research. The investigation will provide insight into the substrate such that a general understanding on its stability could be established. If successful, the established mechanism will allow future research to better fine-tune and manipulate the performance of the substrates for more diverse properties and applications. Similar to the research that serves as the foundation of this work, the keratin will be obtained from human hair via an extraction process established previously. The substrate was then fabricated through a ‘one-pot’ mixture of keratin and cellulose to form the keratin substrate as per preceding work. However, in between the mixing stage and freeze-drying process, autoclave and freeze-thawing were introduced to study its validity as stability mechanism factors. Experimental techniques were employed to gain insights into the substrates, thermal and mechanical stability characteristics. Field test was also conducted to observe substrate performance in realistic growing conditions. Resultant substrates were porous and displayed impressive mechanical and thermal properties (indicators of stability). Furthermore, it delivered promising results under realistic growth environments, showing potential in its application. Overall, our study was able to give insight on the mechanism of the substrate and determine that the changes introduced did not hinder the primary intention of using the substrate as biodegradable growth media for urban farm. Looking into the future, we hope to provide a more comprehensive understanding of the substrates developed such that ourselves and others could better apply and condition it to suit unique needs. Consequentially, that will resolve issues associated with wastage incurred by keratin and in urban farming practices when users switch over from existing non-biodegradable products to our biodegradable option.