Influence of industrial symbiosis on solid waste reuse in manufacturing industries in Kisumu county, Kenya

Abstract

The growth of the manufacturing sector signifies economic progress, but waste generation poses a notable drawback, creating significant environmental challenges. Effective waste management, particularly the reuse of solid waste, remains a critical issue for industries striving towards green growth and circularity. Traditional waste management practices are often inefficient, contributing to environmental degradation and missed opportunities for resource optimization. Addressing the problem of solid waste reuse requires innovative approaches such as Industrial Symbiosis (IS) that integrate economic and environmental benefits. IS, a cooperative approach where industries exchange materials, energy, water, and byproducts, offers a sustainable alternative to conventional solid waste disposal methods. Industries can minimize waste, reduce costs, and promote circular economies through IS. Despite its potential, research on IS has primarily concentrated on its technical aspects, particularly in developed countries, while the social dimensions of IS—such as geographical proximity, information flows, and the intensity of industrial cooperation—remain underexplored. Understanding these social interactions is vital for creating effective IS networks, yet research in African contexts, including Kisumu County, Kenya, is lacking. Studies in Kisumu have primarily addressed waste management challenges and end-of-pipe solutions but have not sufficiently explored how IS can drive more sustainable solid waste reuse. This study aimed to fill that gap by examining how IS influences solid waste reuse in Kisumu County's manufacturing industries. The specific objectives were to determine the influence of geographical proximity on type of solid waste-material exchanged, examine association between information flows and type of solid waste-material exchanged and lastly, examine the influence of symbiotic intensity on amount of solid waste-material reused in the network. This study employed a descriptive cross-sectional research design. The exchange network theory guided the study. A total population sampling approach was utilized following the application of specific inclusion and exclusion criteria to industries. Among the 49 industries that satisfied the criteria, only 41 consented to participate in the study. Fieldwork was conducted between August and October 2021. Data was collected through surveys and interviews with five key stakeholders from the Kisumu County Government in the Department of Water, Environment, Natural Resources and Climate Change, Department of Physical Planning, Lands and Urban Development, Department of Energy and Industrialization, Kenya Association of Manufacturers and National Environmental Management Authority. The study established that geographical proximity did not significantly influence the type of waste exchanged (p = 0.687). Information flows showed a significant relationship between the frequency of communication and the type of waste exchanged (p = 0.013), although the type of information exchanged was not statistically significant (p ≥ 0.005), limiting the ability to detect relationships. Symbiotic intensity, however, significantly influenced the amount of waste reused (p = 0.039). The study concluded that geographical proximity may not be a decisive factor in determining the types of solid waste exchanged within industrial symbiosis in Kisumu County. The type of information exchanged did not significantly influence the type of waste exchanged, but communication frequency strongly influenced solid waste reuse, implying it's not what information is exchanged but the frequency of communication that influences waste exchange. Lastly, symbiotic intensity significantly influences solid waste reuse, with a greater impact observed from increasing the number of actors within a network compared to increasing the types of waste exchanged. The study recommends improving data collection and monitoring efforts related to waste reuse across the region to help track IS initiatives across different proximities, enhancing information flows and increasing the number of industries in the IS network to promote more solid waste reuse. These findings can inform and benefit policymakers, manufacturing industries, and environmental regulators on how to optimize IS networks. Future research should explore the role of economic incentives, communication channels, and policy support in industrial symbiosis and assess how technology, innovation, and information flows impact solid waste reuse and symbiotic intensity.