Advanced Materials Research Vols. 779-780

Abstract: Based on the main factor of hydraulic loading, removal of nitrogen and phosphorus and effluent quality of rural domestic wastewater were studied in subsurface constructed wetlands-ponds system in Jiangxi Province. The results showed that there had good processing results on nitrogen and phosphorusremoval by subsurface constructed wetlands-ponds system,especially on removal of phosphorus.In the combined system removal influence of nitrogen and phosphorus were affected by hydraulic loading,it was influenced more significantly for nitrogen removal and had less influence on removal effect of phosphorus relatively.When the hydraulic loading was 72 m³·m^-2·d^-1, removal rate of TNNH₃-NTP were 75.3%76.08%86.77% respectively,which was very good for the combined system;removal rate of TNNH₃-NTP were 42.67%33.62%61.72% in the subsurface constructed wetlands; removal rate of TNNH₃-NTP were 32.63%42.46%25.05% in the ponds.While hydraulic loading was lower,the subsurface constructed wetlands was the control factor for the combined system.With the increasing of hydraulic loading,the ponds was the control factor gradually. In the combined system, effluent quality of TN was superior to the first class B criteria specified in GB 18918-2002(15mg·L^-1),effluent quality of NH₃-N was superior to the first class B criteria (8mg·L^-1), effluent quality of TP was superior to the case-Vwaters of surface water quality (GB3838-2002) standard (0.4 mg·L^-1) .Research results could be the basis of combined system in Jiangxi Province.

Abstract: This paper describes the training, validation and application of recurrent neural network (RNN) models to computing the algal dynamic variation at three sites in Gonghu Bay of Lake Taihu in summer. The input variables of Elmans RNN were selected by means of the canonical correspondence analysis (CCA) and Chl_a concentration as output variable. Sequentially, the conceptual models for Elmans RNN were established and the Elman models were trained and validated on daily data set. The values of Chl_a concentration computed by the models were closely related to their respective values measured at the three sites. The correlation coefficient (R²) between the predicted Chl_a concentration by the model and the observed value were 0.86-0.92. And sensitivity analysis was performed to clarify the algal dynamic variation to the change of environmental factors. The results show that the CCA can efficiently ascertain appropriate input variables for Elmans RNN, the Elmans RNN can precisely forecast the Chl_a concentration at three different sites in Gonghu Bay of Lake Taihu in summer and sensitivity analysis validated the algal dynamic variation to the change of environmental factors which were selected by CCA.

Abstract: Based on test results of physical model, flow rate and regime and sediment deposit of underground hydroelectric station and diversion canal within 70-year operation of Three Gorges Project (TGP) have been analyzed. The primary reason of complicated flow regime before underground station is the confluence and interaction of two spout of flow, one comes from the diversion channel of underground hydroelectric station, the other comes from the communicating canal between underground station and right bank station, caused by excavation of Pianyanzi-mountion adjacent to dam. The head lose of power generation was increased due to that the increasing of the projects operational time, amount of sediment deposit before dam and discharge through the communicating canal strengthened intensity of reflow and surface velocity of approach. In order to make the mixed flows become single and forward flows in flood season, as well as reduce head lose of the station and improve the unit power generation benefit, we suggest to build dividing dike of communicating canal during the projects early operation time.

Abstract: The paper uses the research means of numerical simulation for marine pollution problem of the ocean dumps from offshore industries, which is concerned by the coastal countries; it adopts ECOM Water Quality Model. It has carried out the simulation research on those projects influence on the environment of sea area. By taking COD of wastewater as the research object, the paper confirmed the influence range of COD emission on marine ecological environment.

Abstract: Sensitivity analysis of bioretention cell design elements can provide a theoretical basis for the design and construction of a bioretention cell. This study uses the storm management model (SWMM) and the bioretention infiltration RECARGA to generate runoff and outflow time series for calculation of hydrologic performance metrics. The hydrologic performance metrics include: the overflow ratio, groundwater recharge ratio, ponding time and underdrain flow ratio. The FAST method is chose to analyze sensitivity of design elements for two types of bioretention cell, one without underdrain and the other with underdrain. The results show that the surface area is the most sensitivity to most the hydrologic metrics for both types of bioretention, while the planting soil depth and the gravel depth are the two least sensitive elements. The saturated infiltration rates of planting soil and native soil are another two sensitive elements for bioretention cells without underdrain, but the saturated infiltration rate of planting soil and underdrain size are another two sensitive design elements for bioretention cells with underdrain.Keywords: Global sensitivity analysis; bioretention cell; design elements; FAST

Abstract: Base on the observation on the core of the Upper Ganchaigou Group of Youshashan Oilfield in Qaidam Basin (N1) and the analysis into the sedimentary background and structure, as well as previous foundings, the Neogene Period in the River Delta can be found as a-shallow lake deposition environment. The Upper Ganchaigou group in the study area is dominated by sandstone, siltstone, clay rock and little carbonate rocks. The sedimentary structures are rich, and it mainly includes: gutter cast (pocket structure), scour surface and truncated structure, hummocky cross-bedding, lapped bedding, wave bedding and so on. By summing up the above characteristic, this area is thought to have the characteristics of storm deposits, and in accordance with the storm sedimentary sequence, a sedimentary model is established.

Abstract: The mangrove marshes are important for coastal ecosystem and play an important and irreplaceable role in the maintenance of coastal biodiversity. A mangrove transect and a bald beach transect with similar topography were selected for comparison study in Dongzhaigang National Nature Reserve, Hainan. The observation wells were installed and then the pore water sample was collected. The constant elements and trace elements of the pore water were analyzed. Based on the results, the trace elements of the two transects were discussed. It was found that the concentration of antimony and lead of mangrove marsh are higher than that of bald marsh, which most probably due to the contamination of anthropogenic activity. The method of decreasing the concentration of trace elements in mangrove marsh is proposed.

Abstract: The aim of this work is to study effect of two powerful oxidants (potassium permanganate and chlorine) on natural organic matter in surface waters. Trials are conducted out with three Algerian surface waters under controlled experimental conditions (oxidant dose applied and contact time). Permanganate was used alone in the first step, while the combination permanganate-chlorine was used in the second step.As for chlorine demand, permanganate consumption seems correlated with physicochemical characteristics of waters and particularly the nature and content of organic matter. The effect of a coupling preoxidation by permanganate / post-chlorination resulted in a decrease of chlorine consumption and amounts of produced trihalomethanes.

Abstract: Energy consumption in the Chinese rural areas features massive use of low-grade energy commodities and the distempered structure of exorbitant leaning on biomass energy. This has provoked an increasingly exacerbating environment and exerted a depressing effect on agriculturally sustainable development. Pilot energy engineering practices of efficient utilization environment improvement have seen a surge on a vast extent of rural lands. As a typical engineering of energy resources for methane production, the four-dimension-inone-geometry model concerning ecological agriculture has triggered scholarly attention. The aim of this study is to deal with energy flows in this system whereby to put forward measures for its upgrading and ultimately offer policies for rural energy development and use. First, the study depicts the models structure and working process, and the methodology of estimating its energy flows. Next, taking a three member household as an example, the study estimates the quantity in its energy flows, finding that the whole system imports 1,195,102 MJ of energy and generates 35,728MJ, with 47.3% yielded by the breeding system, 32.1% by the anaerobic fermentation system, and 20.6% by the planting system. Comparatively, this model has neither achieved the artificially auxiliary energy-output ratio of 2.4:1, a criterion for high yield, nor reached the national high output standard of 38.1GJ/hm² in inorganic energy investment and the height of 124.3 GJ/hm² of farmland energy input in the bio-energy zones of good harvest. On this ground, this study presents countermeasures to further improve the models energy efficiency and strategies related to rural energy development. Those suggestions might apply to other rural areas.

Abstract: To investigate the effects of gangue on pyrolysis of municipal solid waste (MSW), pyrolysis of MSW with gangue has been conducted by TG and fixed-bed reactor, respectively. The effect of gangue on pyrolysis product yields and compositions of gaseous products was investigated and the obtained results were compared with similar experiments without gangue. It was shown that gangue can improve the pyrolytic reaction of MSW, reduce the char yield, increase the liquid yield. And influences of gangue on yields of H₂, CO, CH₄ and CO₂ were more apparent, the yields of H₂, CO and CO₂ with gangue were improved 12.5%, 11.8% and 175%, respectively, conversely, the yield of CH₄ was reduced 15.4% compared with no gangue.