Spatial Patterns of Urban Wastewater Discharge and Treatment Plants Efficiency in China.

Min An,Zaiyi Liao,Weijun He,Zhaofang Zhang,Liang Yuan,Dagmawi Degefu

doi:10.3390/ijerph15091892

Abstract

With the rapid economic development, water pollution has become a major concern in China. Understanding the spatial variation of urban wastewater discharge and measuring the efficiency of wastewater treatment plants are prerequisites for rationally designing schemes and infrastructures to control water pollution. Based on the input and output urban wastewater treatment data of the 31 provinces of mainland China for the period 2011–2015, the spatial variation of urban water pollution and the efficiency of wastewater treatment plants were measured and mapped. The exploratory spatial data analysis (ESDA) model and super-efficiency data envelopment analysis (DEA) combined Malmquist index were used to achieve this goal. The following insight was obtained from the results. (1) The intensity of urban wastewater discharge increased, and the urban wastewater discharge showed a spatial agglomeration trend for the period 2011 to 2015. (2) The average inefficiency of wastewater treatment plants (WWTPs) for the study period was 39.2%. The plants’ efficiencies worsened from the eastern to western parts of the country. (3) The main reasons for the low efficiency were the lack of technological upgrade and scale-up. The technological upgrade rate was −4.8%, while the scale efficiency increases as a result of scaling up was −0.2%. Therefore, to improve the wastewater treatment efficiency of the country, the provinces should work together to increase capital investment and technological advancement.

Highlights

Urban wastewater discharge is one of the main sources of surface and groundwater pollution in China [1]
Urban wastewater treatment plants (WWTPs) Malmquist index parts of the country between 2011 and 2015. This was mainly due to technological improvements
Hainan’s, Shandong’s and Ningxia’s technical efficiency change rate (TEC) declined; these three provinces should focus on improving the efficiency of their municipal wastewater

Summary

Introduction

Urban wastewater discharge is one of the main sources of surface and groundwater pollution in China [1]. It has exceeded industrial pollution and, since 1998, it has become the largest source of environmental pollution in China [2,3]. With economic development and the intensification of urbanization, the discharge of urban wastewater is increasing year by year. In 2015, urban domestic wastewater discharge was 535.2 billion tons, 4.9% higher than 2014, and accounted for 72.8% of the total wastewater discharge in China [4]. The increase in urban wastewater discharge raises health risks [5,6]. It threatens the sustainability of the country’s water resources and the socio-economic and environmental systems. Information on the spatial variation of the wastewater discharge and the efficiency of wastewater treatment plants across

Methods

Results

Conclusion