Comparative Analysis of Solid Waste Generation Statistics and Regional Population Numbers (The Case of Douala City, Cameroon)

Objective: The objective of this study is to analyze population statistics and municipal solid waste (MSW) volume in the Douala, Cameroon region. The aim is to develop a methodology for comparing their respective growth rates over the period from 2003 to 2021. To achieve this, the study seeks to: present population and MSW volume as time series; find mathematical models for the trends of these time series; and develop a method to compare their growth rates. The concept of local sustainable development, titled the 4R-VD system, is proposed as a solution to tackle environmental threats. Theoretical Framework: This paper's theoretical framework is implicitly built upon several key concepts and their interrelationships, grounded in principles of environmental science, urban planning, and applied statistics. Essentially, it blends the theory of environmental impact (the relationship between population numbers and waste generation), sustainability principles (emphasizing controllable waste management), and applied statistical methods (time series and correlation analysis). These elements are jointly employed to empirically test and quantify these relationships, forming the basis for informed policy solutions. Method: This paper outlines a method to analyze the relationship between solid waste (SW) generation and population numbers in Douala, Cameroon, from 2003 to 2021. The method involves normalizing SW amounts and population figures to their initial 2003 values, rendering them dimensionless. This technique addresses unit differences, enabling direct comparison of their growth rates. Further research steps include: a. correlation analysis to establish the strength of the relationship between SW amount and population figures; b. time series analysis, including the Partial Autocorrelation Function (PACF) for SW amounts, to understand how the current SW amount is affected by past generation. The PACF reveals that the current amount of SW is predominantly influenced by the amount generated in the preceding year; c. mathematical modeling to describe trends: aa) an exponential model is used for population growth, conveying an accelerating increase, bb) linear models are applied to three distinct SW generation periods (2003-2009, 2009-2019, and 2019-2021) to capture different growth trends; d. growth rate comparison by analyzing the slopes of dimensionless linear models developed to simulate SW generation and population changes in 2009-2019 and 2019-2021. Results and Discussion: The study's results paint a stark picture of increasing solid waste generation in Douala, Cameroon, relative to its population growth from 2003 to 2021. The findings highlight an uncontrolled and dangerous trend in Douala's waste management. The dramatic acceleration of solid waste growth compared to population growth, particularly in the most recent period, provides strong evidence of a severely escalating environmental threat. We argue that this unsustainable situation necessitates the implementation of the proposed 4R-VD system. This system integrates waste management with other sustainable urban management components, such as energy, transportation, and construction management, to foster a better balanced and resource-efficient area. Research Implications: This paper offers several valuable research implications for urban planning, environmental science, and sustainable development, particularly for rapidly urbanizing areas in developing countries. The paper's key methodological contribution lies in normalizing diverse data into dimensionless values for comparative time-series analysis, providing a robust framework for future research. Findings regarding the exponential increase in per capita waste generation, which significantly outperforms population growth, highlight the need for an in-depth investigation into specific factors driving this acceleration. The mathematical models applied to simulate population and waste generation growth serve as a basis for more sophisticated forecasting and scenario planning. Finally, the application of the 4R-VD system opens new avenues for research into integrated, holistic approaches to urban sustainability. Originality/Value: This paper significantly contributes to the existing body of knowledge, particularly in solid waste management and urban development in developing countries. This contribution is through its original methodological approach and the alarming insights it identifies. The paper's originality stems from its innovative analytical methodology, while its value lies in providing critical, data-driven insights into relevant environmental issues within a data-poor context, thereby offering both a warning and a conceptual pathway towards more sustainable urban management.