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A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer

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Frontiers of Environmental Science & Engineering 2019年第4期13卷 179-190页

作者： Nan Zhao Huu Hao Ngo Yuyou Li Xiaochang Wang Lei Yang Pengkang Jin Guangxi Sun School of Environmental and Municipal Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Centre for Technology in Water and Wastewater School of Civil and Environmental EngineeringUniversity of TechnologySydneyNSW 2007Australia Department of Civil and Environmental Engineering Tohoku UniversitySendaiMiyagi 980-8579Japan Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China

Presently, several activated sludge models (ASMs) have been developed to describe a few biochemical processes. However, the commonly used ASM neither clearly describe the migratory transformation characteristics of fermentation nor depict the relationship between the carbon source and biochemical reactions. In addition, these models also do not describe both ammonification and the integrated metabolic processes in sewage transportation. In view of these limitations, we developed a new and comprehensive model that introduces anaerobic fermentation into the ASM and simulates the process of sulfate reduction, ammonification, hydrolysis, acidogenesis and methanogenesis in a gravity sewer. The model correctly predicts the transformation of organics including proteins, lipids, polysaccharides, etc. The simulation results show that the degradation of organics easily generates acetic acid in the sewer system and the high yield of acetic acid is closely linked to methanogenic metabolism. Moreover, propionic acid is the crucial substrate for sulfate reduction and ammonification tends to be affected by the concentration of amino acids. Our model provides a promising tool for simulating and predicting outcomes in response to variations in wastewater quality in sewers.

关键词： Gravity sewer Modeling pollutant transformation Biochemical reaction process

Modeling pollutant transport in overland flow over non-planar and non-homogenous infiltrating surfaces

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第2期14卷 110-119页

作者： Zhi-guo HE Gokmen TAYFUR Qi-hua RAN Hao-xuan WENG Department of Ocean Science and Engineering Zhejiang University Department of Civil Engineering Izmir Institute of TechnologyGulbahce KampusUrlaIzmir 35340Turkey Department of Hydraulic Engineering Zhejiang University

pollutant transport in overland flow over surfaces with spatially varying microtopography,roughness,and infiltration was investigated using the diffusion wave equation and transport rate-based *** finite volume method in space and an implicit backward difference scheme in time were employed in the numerical solution of the 2D governing *** developed model was first tested against an analytical solution and an experimental study involving overland flow and the associated pollutant transport,subsequently a series of numerical tests were carried ***-point source pollution was investigated under spatially varying microtopography,roughness,and *** simulation results showed that microtopography and roughness were the dominant factors causing significant spatial variations in solute *** the spatially varying microtopography was replaced by a smooth surface,the result was an overestimation of the solute rate at the outlet of the *** the other hand,when the spatially varying roughness was replaced by the average roughness and spatially varying infiltration rate by the average infiltration rate,the pollutant discharge at the outlet of the upland was not significantly *** numerical results further showed that one cannot ignore the spatial variations of slope and roughness when investigating the local pollutant concentration distribution.

关键词： Diffusion wave Variation Topography Roughness Infiltration pollutant Modeling Overland flow

Study of pollutant transport in depth-averaged flows using random walk method

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Journal of Hydrodynamics 2019年第2期31卷 303-316页

作者： Xue-fei Wu Dongfang Liang School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Department of Engineering University of CambridgeCambridgeUK

The random walk particle tracking(RWPT)method is compared with the Eulerian methods in investigating pollutant transport in depth-averaged *** a typical representative of the Eulerian model with high performance,the MacCormack scheme with Total Variation Diminishing modification(TVD-Mac)is selected for *** concentration is simulated in four case ***,both numerical models have been tested in two idealized cases and compared against analytical *** dissipation is observed for TVD-Mac model where the concentration changes abruptly,especially under the circumstances of low resolution and misalignment between the flow direction and grid *** the contrary,simulations by the random walk model achieve higher accuracy in both cases and are free of fictitious oscillations in the vicinity of sharp concentration ***,the solute oscillation along a one-dimensional hypothetical tidal estuary is simulated,with the RWPT accurately con serving mass and suffering less rm merical diffusion compared with the Eulerian ***,the process of pollutant transport in a Yangzte River reach is predicted by the *** longitudinal dispersion coefficient DL is calculated *** is compared favorably with the theoretical/empirical formulae,indicating the validity of the RWPT in solving complex natural problems.

关键词： pollutant transport depth-averaged flows random walk particle tracking TVD-MacCormack

Air pollutant control and strategy in coal-fired power industry for promotion of China’s emission reduction

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Frontiers in Energy 2019年第2期13卷 307-316页

作者： Weiliang WANG Bo LI Xuan YAO Junfu LYU Weidou NI Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education Department of Energy and Power EngineeringTsinghua University Beijing 100084 China Electric Power Planning and Engineering Institute Beijing 100120China Beijing Guodian Longyuan Environmental Engineering Co. Ltd. Beijing 100084China

Coal-fired power industry has always been the major power source in China. As coal-fired power industry consumes around a half of China’s coal production, it is always thought to be a big air pollutant emission source. As more and more strict legislations in coal-fired power industry have been issued by the government, the emission performance in coal-fired power industry has been drastically reduced *** on a brief review of the development of emission control in China’s coal-fired power industry, the affecting mechanism among the development of installed capacities of emission control device, pollutant emission, and emission performances in coal-fired power industry is studied. According to a systematic study on the development of emissions of classified categories, the role of coal-fired power industry as a pollutant source is *** is found that, coal- fired power industry has contributed the most to China5S emission reduction, and the barycenter of air pollutant emission has been transformed to other high energy consumption industries,like heat, iron/steel, and *** some development strategies are suggested, such as maintaining the current emission standard in coal-fired power industry;expending the coal-fired power emission standards to categories of heat generation and supply, nonmetallic mineral production and ferrous metals smelt-ing and processing;and controlling other heavy metal by consulting the method of Hg control.

关键词： coal-fired power industry energy intensive industries pollutant emission control NOx SO2 soot

Effects of water wave motion on pollutant transport in shallow coastal water

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Science China(Technological Sciences) 2002年第6期45卷 593-605页

作者：陶建华韩光 Department of Mechanics Tianjin University Tianjin 300072 China

Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic factor for pollutant transportation in the coastal water. Numerical simulation shows that the pollutant will transfer along shore when the incident wave is at an angle to the shoreline. This phenomenon is very significant if the outfall is located in the surfzone. Therefore, in the design of sea outfall, to improve near shore environment, the water wave should be considered as an important hydrodynamic factor.

关键词： pollutant transport, water wave, tide current, longshore current, sea outfall.

Predicting pollutant removal in constructed wetlands using artificial neural networks(ANNs)

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Water Science and Engineering 2020年第1期13卷 14-23页

作者： Christopher Kiiza Shun-qi Pan Bettina Bockelmann-Evans Akintunde Babatunde Hydro-environmental Research Centre School of EngineeringCardiff UniversityThe ParadeCardiff CF243AAUK School of Civil Engineering University of LeedsLeeds LS29JTUK

Growth in urban population,urbanisation,and economic development has increased the demand for water,especially in water-scarce ***,sustainable approaches to water management are needed to cope with the effects of the urbanisation on the water *** study aimed to design novel configurations of tidal-flow vertical subsurface flow constructed wetlands(VFCWs)for treating urban stormwater.A series of laboratory experiments were conducted with semi-synthetic influent stormwater to examine the effects of the design and operation variables on the performance of the VFCWs and to identify optimal design and operational strategies,as well as maintenance *** results show that the VFCWs can significantly reduce pollutants in urban stormwater,and that pollutant removal was related to specific VFCW *** based on the artificial neural network(ANN)method were built using inputs derived from data exploratory techniques,such as analysis of variance(ANOVA)and principal component analysis(PCA).It was found that PCA reduced the dimensionality of input variables obtained from different experimental design *** results show a satisfactory generalisation for predicting nitrogen and phosphorus removal with fewer variable inputs,indicating that monitoring costs and time can be reduced.

关键词： Constructed wetlands Urban stormwater pollutant removal Artificial neural networks(ANNs) Principal component analysis(PCA)

Numerical simulation of wind-driven circulation and pollutant transport in Taihu Lake based on a quadtree grid

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Water Science and Engineering 2019年第2期12卷 108-114页

作者： Xiao-dong Liu Ling-qi Li Peng Wang Zu-lin Hua Li Gu Yuan-yuan Zhou Lu-ying Chen Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education Nanjing 210098China College of Environment Hohai UniversityNanjing 210098China

In this study,a two-dimensional flow-pollutant coupled model was developed based on a quadtree *** model was established to allow the accurate simulation of wind-driven flow in a large-scale shallow lake with irregular natural boundaries when focusing on important smallscale localized flow *** quadtree grid was created by domain *** governing equations were solved using the finite volume method,and the normal fluxes of mass,momentum,and pollutants across the interface between cells were computed by means of a Godunov-type Osher *** model was employed to simulate wind-driven flow in a circular basin with non-uniform *** computed values were in agreement with analytical *** results indicate that the quadtree grid has fine local resolution and high efficiency,and is convenient for local *** is clear that the quadtree grid model is effective when applied to complex flow ***,the model was used to calculate the flow field and concentration field of Taihu Lake,demonstrating its ability to predict the flow and concentration fields in an actual water area with complex geometry.

关键词： Numerical simulation Wind-driven circulation pollutant transport Quadtree grid Shallow-flow hydrodynamics Taihu Lake

Spatial flow influence factor: A novel concept for indoor air pollutant control

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Science China(Technological Sciences) 2006年第1期49卷 115-128页

作者： ZHANG Yinping LI Xiaofeng WANG Xinke DENG Wei QIAN Ke Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China

This paper puts forward a novel concept, the spatial flow influence factor (SFIF), which provides a new insight into the airflow structure. This concept is very helpful in the control of indoor air pollutants since: (1) for a given indoor airflow; given sources of volatile organic compounds (VOCs), the optimal arrangement of the VOC sources can easily be obtained; (2) for given positions of VOC sources; occupied regions (or target regions), the optimal indoor airflow pattern or organization can be determined; (3) the SFIF for an indoor space can also be regarded as the indoor air safety index of that space. To illustrate this concept, we present several examples of applying a SFIF to indoor air VOC control.

关键词： volatile organic compounds, indoor air quality, indoor air pollutant control, spatial flow influence factor.

Spatial Distribution Assessment and Source Apportionment of Land-Based pollutant Yield from Qingdao, China

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Journal of Ocean University of China 2019年第1期18卷 151-158页

作者： SU Ying LIANG Shengkang ZHANG Peng WANG Xiulin Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Chemistry and Chemical Engineering Department Ocean University of China Environmental Science and Engineering Department Ocean University of China

The spatial distribution of chemical oxygen demand(COD) and total nitrogen(TN) yield from Qingdao are studied by comparing pollutant yield amount, densities and spatial aggregation(Getis-Ord indexes) among the land-based pollutant source regions(PSRs) entering the three sub-seas(i.e. the Jiaozhou Bay(JZB), other coastal area in the Yellow Sea(OCAYS) and Laizhou Bay(LZB), respectively). Industrial composition of the loads are also studied by comparing pollutant yield among the sources of agriculture, rural domesticity, industry, urban domesticity and service, and calculation of Gini coefficient. Results show that spatial distribution of COD and TN yield from Qingdao are extremely unbalanced. The JZB, with less than 3% of the total coastal sea area of Qingdao, received 62% COD load and 65% TN yield from Qingdao, while the OCAYS, with more than 97% area, only received 23% COD and 20% TN, which consist with the much worsen water quality of JZB than that of OCAYS. On the other hand, the source apportionment of COD and TN loads in the PSRs entering JZB and the OCAYS was similar. The agricultural and domestic sources with high pollution intensity account for more than 80%, while the industrial and service sources with low pollution intensity account for less than 20%. While Gini coefficients, COD 0.81 and TN 0.84 which are much higher than the ‘imbalance' threshold of 0.4, show the uneven industrial structure of Qingdao. These results may be useful in the determination of land-based pollution total amount control at the PSR level.

关键词： Qingdao land-based pollutant pollutant yield pollution intensity industrial structure