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Arid Land Geography ›› 2021, Vol. 44 ›› Issue (4): 971-982.doi: 10.12118/j.issn.1000–6060.2021.04.10

• Climatology and Hydrology • Previous Articles     Next Articles

Natural evaporation processing of high saline wastewater in semi-arid area

GUO Yuntong1(),SHAO Jingli1(),CUI Yali1,ZHANG Qiulan1,LIU Yanming2   

  1. 1. College of Water Resources and Environment, China University of Geosciences(Beijing), Beijing 100083, China
    2. China Institute of Geo-environment Monitoring, Beijing 100083, China
  • Received:2020-01-11 Revised:2021-04-30 Online:2021-07-25 Published:2021-08-02
  • Contact: Jingli SHAO E-mail:252040048@qq.com;jshao@cugb.edu.cn

Abstract:

To enable a deep understanding of the influence of meteorological factors and TDS on the evaporation of saline wastewater in semi-arid areas, as well as to provide a reference and basis for the construction, operation, and management of evaporation ponds, based on the evaporation and meteorological data of the experimental station and Ejin Horo County, Inner Mongolia Autonomous Region, China, this paper analyzed natural evaporation processing of high saline wastewater. The influence degree of different meteorological factors on the water surface evaporation was analyzed using correlation analysis and the gray correlation method. On this basis, a local theoretical evaporation formula was determined by comparing different theoretical formulas to calculate the evaporation and measured evaporation. Finally, the influence of TDS on the evaporation of saline wastewater with different concentrations was analyzed using a linear regression analysis. The results show that the evaporation of fresh water is positively correlated with the net radiation of the water surface and air temperature, negatively correlated with humidity, and insignificantly correlated with the wind speed during the experimental period. The order of the effects of the meteorological factors on evaporation was net radiation from water surface>temperature>wind speed>humidity. Tong Hongliang’s formula can best represent the influence of the meteorological factors on the evaporation of the water surface because its calculation result of 205.76 mm was closest to the actual local evaporation of 205.51 mm during the experimental period. The relative evaporation rates of different TDS water samples were approximately linearly correlated with their TDS values (R2=0.95). In addition, the relative evaporation rate was discussed from the point of view of the temperature effect and solution composition. It is thought that the difference between the experimental value and the actual recorded value of the evaporation pool might be due to the decrease in the solution saturation caused by temperature, while the difference between the theoretical and experimental values might be due to the fact that the saline wastewater was treated as an ideal solution in the calculation without considering the interaction force between the molecules of each component in the solution. Therefore, attention should be paid to local meteorological factors in the site selection of evaporating ponds and the precipitates from the evaporating ponds should be treated in a timely manner to keep the influence of TDS from increasing during evaporation. In this study, field experimental data were used to investigate the natural evaporation processing of high saline wastewater in a semi-arid area. In addition to considering conventional meteorological factors, the influence of TDS on evaporation was considered. Therefore, the results have practical significance for guiding the treatment of salt-bearing wastewater in semi-arid regions.

Key words: high saline wastewater, evaporation model, evaporation experiment, relative evaporation rate, TDS, Raoul’s law, semi-arid area