Using Real-Time Data and Unsupervised Machine Learning Techniques to Study Large-Scale Spatio–Temporal Characteristics of Wastewater Discharges and their Influence on Surface Water Quality in the Yangtze River Basin
| Autor: | Zhenzhen Di, Yang Li, Miao Chang, Peikun Guo, Yin Chang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
lcsh:Hydraulic engineering
Geography Planning and Development 0207 environmental engineering point pollution sources 02 engineering and technology 010501 environmental sciences Aquatic Science sewage outlets 01 natural sciences Biochemistry Industrial wastewater treatment correlation relationship lcsh:Water supply for domestic and industrial purposes lcsh:TC1-978 real-time monitoring data expectation–maximization clustering algorithm 020701 environmental engineering Cluster analysis 0105 earth and related environmental sciences Water Science and Technology Pollutant lcsh:TD201-500 Chemical oxygen demand Environmental engineering Medoid partitioning around medoids clustering algorithm Wastewater Environmental science Water quality Surface water |
| Zdroj: | Water, Vol 11, Iss 6, p 1268 (2019) Water Volume 11 Issue 6 |
| ISSN: | 2073-4441 |
| Popis: | Most worldwide industrial wastewater, including in China, is still directly discharged to aquatic environments without adequate treatment. Because of a lack of data and few methods, the relationships between pollutants discharged in wastewater and those in surface water have not been fully revealed and unsupervised machine learning techniques, such as clustering algorithms, have been neglected in related research fields. In this study, real-time monitoring data for chemical oxygen demand (COD), ammonia nitrogen (NH3-N), pH, and dissolved oxygen in the wastewater discharged from 2213 factories and in the surface water at 18 monitoring sections (sites) in 7 administrative regions in the Yangtze River Basin from 2016 to 2017 were collected and analyzed by the partitioning around medoids (PAM) and expectation&ndash maximization (EM) clustering algorithms, Welch t-test, Wilcoxon test, and Spearman correlation. The results showed that compared with the spatial cluster comprising unpolluted sites, the spatial cluster comprised heavily polluted sites where more wastewater was discharged had relatively high COD (> 100 mg L&minus 1) and NH3-N (> 6 mg L&minus 1) concentrations and relatively low pH (< 6) from 15 industrial classes that respected the different discharge limits outlined in the pollutant discharge standards. The results also showed that the economic activities generating wastewater and the geographical distribution of the heavily polluted wastewater changed from 2016 to 2017, such that the concentration ranges of pollutants in discharges widened and the contributions from some emerging enterprises became more important. The correlations between the quality of the wastewater and the surface water strengthened as the whole-year data sets were reduced to the heavily polluted periods by the EM clustering and water quality evaluation. This study demonstrates how unsupervised machine learning algorithms play an objective and effective role in data mining real-time monitoring information and highlighting spatio&ndash temporal relationships between pollutants in wastewater discharges and surface water to support scientific water resource management. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|