Analysis of temporal and spatial changes and influencing factors of sewage treatment rates of small towns in Chongqing

Abstract

Small towns are the bridge between urban and rural areas, and their sewage treatment is the focus and problem of urban construction. With Chongqing as the research object, this study explores the influencing factors and the characteristics of temporal and spatial changes in sewage treatment rates of 756 small towns in Chongqing from 2014 to 2020 from four aspects: the overall situation, space, population, and industry. The results show that 1) the sewage treatment rates of small towns showed a certain trend of improvement since 2014 and that the polarization between small towns continued to decrease. 2) The sewage treatment rates of small towns presented a significant spatial correlation in their entirety, but the correlation weakened year by year. In 2014, the sewage treatment rates of small towns were mainly high-high clusters, while those in 2017 were mainly low-low clusters and those in 2020 were low-low clusters in a scattered manner. 3) The sewage treatment rates of small towns with a population of 40,000–60,000 and over 60,000 in 2014 were relatively high, but the gap narrowed year by year. Small towns with more than 60,000 people had the highest sewage treatment rate in 2020, but the gap between the lowest values was reduced to 11.94%. 4) In 2014, small towns with tourism as the leading industry had a significant advantage, but three types of small towns, including industrial and mining towns, were improving fast. 5) Land urbanization, the radiation effect of county towns, the investment in urban construction, population size, and leading industries all had notable driving effects on the increase in sewage treatment rates of small towns, but the impact of urban construction investment was relatively weak because it contained a large scale of real estate investment.