Water environmental capacity is an essential component of water environmental assessment and must be monitored and managed for economic, engineering, and human health reasons. Many efforts have been made to study methods for the calculation of water environmental capacity. This paper reviews available literature on water environmental capacity. The evolutionary history and application scenarios of major water quality models, and water environmental capacity calculation formulas are summarized. Through the analysis of calculation formulas for water environmental capacity, it is found that endogenous pollution factors influence the values of degradation coefficient K and retention coefficient R in water environmental capacity calculation though few studies consider such factors. Therefore, the quantification of endogenous pollution factors (particularly the rheological properties of bed sediments) is important and needs further study.

In recent years, oil spill happens in river frequently, which has serious impact on the ecological environment and human health. So it is very important to conduct research on the pollution control technologies of oil spill in the river water. This paper analyzes the domestic and overseas existing oil spill pollution control technologies and puts forward the method combining oil recycling machine and oil dispersant to deal with the pollution caused by oil spill in Changqing Oilfield. Through the comparison, the turntable oil recycling machine and the SC-Y17 oil dispersant are finally selected. According to the experiment, we find that temperature has a great influence on the effect of oil dispersant and measures should be taken to improve the property to make it can adapt to the requirements of the low temperature environment.

The phenomenon of wax deposition is an extremely important issue in the petroleum industry. Researching it is of great help for the oil exploration, gathering, and transportation. This paper described the phenomenon of wax deposition, discussed the mechanism, analyzed the influencing factors and proposed the positive significance of the phenomenon of wax deposition on crude oil production and safe operation in oil gathering and transportation pipeline.

It is very important for reservoir management to estimate the sedimentation amount deposited in a reservoir. Firstly, the formula for estimating the bed load transport rate in the bed of sand waves of prototype by model experiment was derived based on the similarity of grain Froude number; Secondly, several model experiments that the bed forms is similar with the prototype were carried, and the formula was verified. As a result, when the ratio of grain diameter in the prototype and model is great enough, and the bed forms in the model is similar with that in the prototype, a satisfactory result can be obtained by using the estimation formula for estimating the bed load transport rate of the prototype that sand waves occur in the bed.

The theoretical backing of the similarity laws obtained from dual dimensionless parameters of the bed-form classification diagram is given by solving the equations of similarity conditions which is obtained from 1-Dimensional equation of motion, continuity equation, bed deformation equation and the formula of bed load transport. Secondly, the validity of the similarity laws is confirmed by comparing the bed form of distorted model experiment with that of undistorted model experiments performed by Hokkaido Development Bureau (H.D.B.). And also the fact that the height of bar in a gentle curved river channel can be estimated by the result of distorted model of straight flume is found.