As a new low volume application technology, unmanned aerial vehicle (UAV) application is developing quickly in China. The aim of this study was to compare the droplet deposition, control efficacy and working efficiency of a six-rotor UAV with a self-propelled boom sprayer and two conventional knapsack sprayers on the wheat crop. The total deposition of UAV and other sprayers were not statistically significant, but significantly lower for run-off. The deposition uniformity and droplets penetrability of the UAV were poor. The deposition variation coefficient of the UAV was 87.2%, which was higher than the boom sprayer of 31.2%. The deposition on the third top leaf was only 50.0% compared to the boom sprayer. The area of coverage of the UAV was 2.2% under the spray volume of 10 L/ha. The control efficacy on wheat aphids of UAV was 70.9%, which was comparable to other sprayers. The working efficiency of UAV was 4.11 ha/h, which was roughly 1.7–20.0 times higher than the three other sprayers. Comparable control efficacy results suggest that UAV application could be a viable strategy to control pests with higher efficiency. Further improvement on deposition uniformity and penetrability are needed.

Coal chemical energy industry has developed rapidly due to the primary position of coal in energy reserves in China. At the same time, coal chemical industry is also a high-water consumption industry. What’s more, coal chemical wastewater contains high concentration of phenols, NH₃-N, and toxic and harmful substances. In the study, an all-round investigation on wastewater treatment technologies was conducted in projects of the coal chemical industry. These data were analyzed in detail from the aspects of coal-to-gas project, coal-to-oil project, and coal-to-olefin project. In pretreatment, phenol ammonia recovery device is the key section. At present, the process of first de-ammonia with gas stripping method and then de-phenolization with extraction method is mostly adopted in China. In microbiological treatment system, serious odor is diffused around the sewage treatment facilities. Thus, negative pressure extraction measures should be adopted in the microbiological treatment system. In addition, there is no suitable method for the treatment of concentrated brine and crystal salt, so it needs further study. Finally, this research can provide references for the problems of wastewater environment restriction existing in the long-term development of coal chemical industry.