This article experiments wetland-based biochar as an effective adsorbent for phosphorus removal. In this experiment, four common wetland plants, canna (C), umbrella palm (U), bamboo reed (B), and Thalia dealbata (T), were used as the main raw materials. Twelve kinds of biochar (C300, C500, C700, U300, U500, U700, B300, B500, B700, T300, T500, and T700) were obtained at three pyrolysis temperatures (300°C, 500°C, and 700°C). The results show that canna (C) and umbrella palm (U) are more suitable as raw materials for phosphorus removal using biochar. If bamboo reed (B) and Thalia dealbata (T) are used as raw materials for phosphorus removal using biochar, there is a greater risk of phosphorus release. With the increase of pyrolysis temperature (700°C > 500°C > 300°C), there is an increasing trend of phosphorus adsorption effect. The theoretical maximum adsorption capacity of C700, U700, and C500 was 39.24, 7.08, and 7.26 mg P·g−1 at an initial concentration of 50 mg·L−1 phosphorus, respectively. The theoretical adsorption capacity of C700 (Q max = 39.24 mg P·g−1) was much higher than that of the general modified adsorption materials. It also has a larger tolerance range to pH (3–11). The results of kinetic model fitting showed that the adsorption mechanism of C700, U700, and C500 on phosphorus can be better simulated by intra-particle diffusion and Elovich model, and the adsorption mechanism includes surface adsorption and intra-particle diffusion. The fitting of isothermal adsorption model showed that Langmuir–Freundlich equation is more suitable for the description of adsorption characteristics of C700, U700, and C500, and the fitting coefficient R 2 is 0.9928, 0.9949, and 0.9897, respectively. It indicates that the adsorption of phosphorus on C700, U700, and C500 has a balance of uniform and nonuniform surface, and monolayer and multilayer adsorption could occur. The results from this work demonstrated that the biochar obtained from canna at 700°C has good adsorption and phosphorus removal potential without modification, and it can be used as the preferred biochar for phosphorus removal of high concentration with large pH changes. In the final validation experiment, the phosphorus removal rate of C700 was up to 77.4% on the treatment of actual phosphorus containing wastewater.

As the development of ship building technologies, ships have been becoming larger and larger. As a result, the existing ports and waterways can not meet the requirements of safe navigation, berthing and unberthing operations of large ships. In order to ensure the safe berthing and unberthing for large ships, wharf and waterways need to be rebuilt, also it is necessary to check whether the rebuilt wharf can meet the navigation needs. In this paper, the ship handling simulator is used to simulate the safe berthing and unberthing of the pier. This paper establishes the mathematical model of ship motions, generates virtual navigation environment, applies the concepts of track zone width, potential ship handling water area, utility function and risk of berthing operation, and makes a comprehensive analysis of the width of the channel, ship manoeuvring waters and the safety of berthing operation, and puts forward some objective and reasonable suggestions on the safety of berthing. By practical application of ship-handling simulator to evaluate the safety of ship berthing and unberthing, it shows that the method based on ship-handling simulator is objective, feasible and reasonable to analyze and evaluate the navigation safety of wharf engineering, and has a good value of application.

With the wide application of cylindrical FPSO (Floating Production Storage and Offloading, FPSO), more and more people pay attention to its operational safety. To study and explore the safety of cylindrical FPSO offloading operation under extreme weather, it is necessary to conduct the simulation of whole operation process in such conditions. At first, the programming models are formulated for the cylindrical FPSO, shuttle tanker and tugs; then, based on the modelling, the responses of the cylindrical FPSO are simulated during offloading operation under various conditions, combined with Delphin Method and relevant theory. The most unfavorable load state and ultimate wind speed on unfavorable wind direction are explored through three stages: 1. changing the loading status of shuttle tanker and cylindrical FPSO; 2. changing the relative bearing of wind; 3. changing the wind speed. The results showed that when the offloading state is FPSO half-load & tanker half-load, it is the worst state to control the offloading system and the limit wind speed in the simulation is: cross wind ≤20 knots.By analyzing the motion response of cylindrical FPSO which is assisted by two tugs, a relatively objective and reasonable solution is obtained, which provides a beneficial reference for the future cylindrical FPSO offloading operation under the extreme weather conditions.

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