The Role of Centralized Wastewater Treatment in the Rural Alabama Black Belt

Abstract

Centralized and decentralized wastewater treatment systems play a major role in protecting human health and U.S. waters from contamination. However, failing wastewater treatment in the rural Alabama Black Belt has become a prominent issue. In the Black Belt, the status and role of decentralized systems have become well documented. However, there is a lack of research about centralized systems in the Black Belt. Due to the scarcity of research and available literature, this thesis encapsulates the role and status of centralized treatment systems in the rural Black Belt, which excludes Montgomery County since the majority (~87%) of the population is from a metropolitan area. Overall, centralized treatment plays an important role since approximately half (~51%) of the rural Black Belt is served by centralized systems. Additionally, the recent performance of centralized treatment in the Black Belt was evaluated by using 2020 and 2021 quarterly noncompliance violations from the U.S. EPA ECHO (Enforcement and Compliance History Online) database. The performance of small community centralized systems was significantly (p < 0.05) worse in the Black Belt than centralized systems that served the remainder of Alabama. Using a multivariable regression model, the percent of service population in poverty and the type of treatment facility (aerated lagoons, stabilization ponds, or mechanical treatment plants) were determined to be the most significant predictor variables that influenced the recent performance of small community centralized systems in the Black Belt. The other technical variables of treatment facilities (e.g., age of system, flow, annual design flow, method of discharge, service population, size of system, bypasses, and sanitary overflows) and nontechnical characteristics of municipal sewered areas (e.g., median household income, percent black, percent white, percent eighteen years or older, percent sixty-five years or older, percent households below $15,000, percent no high school, percent bachelor's degree or higher, and other socio-demographic variables) had no significant effect on the performance of these systems in the model.