COST EFFECTIVENESS OF RECYCLING ORGANIC WASTE USING BLACK SOLDIER FLY AND EFFECT ON HOUSEHOLD INCOME IN KIAMBU COUNTY, KENYA

Abstract

The adoption of insect-based technologies in managing organic waste is gaining traction. Information on determinants of adoption and the technologies' cost effectiveness is important for policymakers' decision-making on efficient waste management. The study determined the factors influencing the adoption of black soldier fly (BSF) in organic waste recycling, its cost effectiveness compared with conventional composting, and the effect of adopting BSF on household recycling income. Primary data was collected from a sample of 222 households, 105 using BSF and 117 using conventional composting, in Kiambu County and supplemented with secondary data from existing literature. Binary logistic regression, cost-benefit analysis, and endogenous switching regression models were used to determine the determinants of choice to adopt, cost effectiveness, and effect on recycling income, respectively. The empirical results from binary logistic regression revealed that membership in waste management groups, access to waste management extension information, and perception of diversification of recycled products significantly and positively influenced the adoption of BSF in organic waste recycling into fertilizer with odds ratios of 1.801, 3.227, and 15.299, respectively. The cost-benefit analysis indicated that households recycled 4.81 tons and 3.84 tons of organic waste per cycle using BSF and conventional composting. Recycling 1 ton of organic waste per cycle using BSF generated an annual gross margin of 55.36% and a Net Present Value (NPV) of $2128.36 (10 years, 12% discount rate). The NPV was highly sensitive to variations in the quantity and price of fertilizer, production cycle, and labour cost. On the other hand, recycling 1 ton of organic waste per cycle using conventional composting generated an average annual gross margin of 16.63% and NPV of $55.97 (10 years, 12% discount rate). Endogenous switching regression output indicated that the average treatment effect (ATT) of 2.224 (18.68%) indicated that the adoption of BSF positively affected household recycling income. Moreover, households not using BSF would increase their recycling income by 18.78% if they adopt BSF in recycling organic waste into fertilizer. Our findings indicate that BSF is cost- effective and has huge potential in recycling urban and peri-urban organic waste. Policy development on efficient waste management should be aimed at increasing awareness on the economic, environmental and circular economy benefits of using BSF for organic waste recycling. Moreover, households should be encouraged to adopt BSF so that they do not only benefit from recycling organic waste into fertilizer, but also benefit from diversifying their livelihood opportunities.