Sustainable Approach for Green Pesticide Production in Kenya from the Croton Megalocarpus Trees

Shelby Browning and Jeffrey Seay, Ph.D., PE

University of Kentucky College of Engineering Paducah Extended Campus

Croton megalocarpus is a nut-producing tree found all over Sub-Saharan Africa. While this tree offers many benefits to the local people such as shade, wind protection, and soil conservation, the inedible nuts it produces have long been thought of as a waste product. Currently, efforts are underway to press oil from the nuts for use as a biofuel, and the left-over seed cake has been found to be a great animal feed product. This still results in a waste product, the husks from the shelled Croton megalocarpus nuts. Using a process developed by the University of Kentucky Appropriate Technology and Sustainability (UKATS) research team, those wasted croton nut husks can be converted through slow pyrolysis into a product called wood vinegar. Studies suggest that diluting wood vinegar with water creates an effective non-synthetic pest repellent. The left-over biochar can also be pulverized and added to the soil as an organic fertilizer, resulting in almost a zero-waste use of croton nuts.

The focus of this research is to determine the yield of wood vinegar and biochar from Croton megalocarpus husks as a function of moisture content, pyrolysis temperature and the percentage of seeds remaining with the husks after the shelling operation. Response surface methodology (RSM) has been used to construct an experimental plan for the laboratory experiments. The results of this research will be used to optimize the recovery of wood vinegar and biochar from the waste husks.