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Physiological responses of bermudagrass (Cynodon dactylon) to submergence

100%

Tan S. , Zhu M. , Zhang Q.

nr 1

A split-plot design was used to study the physiological responses of anti-oxidative enzymes and carbohydrate contents of bermudagrass to different durations (0, 3, 7, 15, 30, 60, 90, 120 and 150 days) and depths of submergence (0, 1, 5 and 15 m). The results suggest that submergence caused a higher production of malondialdehyde and more significant changes in the different submerged treatments. The activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) in roots increased with the increase of the durations and depths of submergence, implying an integrated pathway involving CAT, SOD, POD, GR and APX for protection against the detrimental effects of activated oxygen species under submergence. Total soluble carbohydrate and starch contents of shoots and roots decreased with the increase of the depth and duration of submergence, but remained at relatively high level at the end of the study, showing quiescence is one of the major strategies of bermudagrass under the stress of submergence. The results suggest that bermudagrass can endure long-term and deep submergence by balancing between the formation and detoxification of activated oxygen species, lowering metabolism and reserving high amounts of carbohydrate.

Polishing of secondary effluent by a two-stage vertical-flow constructed wetland

100%

Zhang C. , Tan S. , Li J. , Peng C.

Polish Journal of Environmental Studies

2015

tom 24

nr 2

A two-stage vertical-flow constructed wetland (VFCW) was built to advanced treatment of secondary effluent containing organic and inorganic nutrients (nitrogen and phosphorus) from a municipal sewage treatment plant in Beijing, China. The results showed that the VFCW effluent achieved 66-83% and 81-90% removal for COD and TP, respectively. Meanwhile, NH₄⁺-N and TN were almost completely removed during stable operation of the wetland system. The VFCW effluent concentrations of COD, TN, and TP were less than 30 mg·L⁻¹, 1.5 mg·L⁻¹, and 0.3 mg·L⁻¹, respectively, which can meet the environmental quality standards for surface water in China. Because of the special design, the better performance of the VFCW was that it allowed the treatment of wastewater under multiple aerobic, anoxic, and anaerobic conditions sequentially in different heights of the CW unit. New media materials, rice husks, and steel slag were the key to the efficient removal of TN and TP. This technology could be adopted to improve the secondary effluent quality.

A planning model for the chemical integrated system under uncertainty by grey programming approach

75%

Ren J. , Tan S. , Dong L. , Zhou Z. , Gao S. , Pan C.

Polish Journal of Chemical Technology

2013

tom Vol. 15, nr 2

16--22

A model to optimize the planning of the chemical integrated system comprised by multi-devices and multi-products has been proposed in this paper. With the objective to make more profits, the traditional model for optimizing production planning has been proposed. The price of chemicals, the market demand, and the production capacity have been considered as mutative variables, then an improved model in which some parameters are not constant has been developed and a new method to solve the grey linear programming has been proposed. In the grey programming model, the value of credibility can be suggested by the decision-makers, and the results of the production planning calculated by the model can help them to achieve their desired target. An actual case has been studied by the proposed methodology, and the proposed methodology can be popularized to other cases.