Fu Sun

Agricultural phosphorus flow and its environmental impacts in China

The transfer of nutrients from agricultural land to waters attracts the attention of policy makers as well as scientists as it plays an increasingly significant role in affecting the water environment. It is therefore essential to first understand the nutrient flow in agricultural systems and then correspondingly formulate a series of cost-effective policies and best management practices (BMPs). On the basis of an emission inventory analysis (EIA) and a nutrient full balance (NFB) calculation, this paper presents a partial substance flow analysis (SFA) method, as well as an Agricultural Phosphorus Flow Analysis (AgiPhosFA) model, to describe the phosphorus (P) flow in the agricultural systems in China and assess the impact of human activities on waters driven by agriculture and rural life. It is estimated that average P input and output were 28.9 kg ha(-1) a(-1) and 14.2 kg ha(-1) a(-1) respectively in China in 2004, while the total P utilization efficiency (Plant uptake P/P input) in agriculture was 45.7% leading to an average P surplus of 14.7 kg ha(-1) a(-1). Excessive P application through mineral fertilizer in the arable farming system has led to the accumulation of soil P and constituted a risk to the recipient water quality, whereas the grassland grazing system is confronted with a severe P deficit problem which has resulted in widespread grass degradation. Therefore it may be an efficient way to mitigate the problems simultaneously by regulating and balancing the P flows between the two systems. Uncertainties of the method and model are also discussed in terms of model conceptualization, data and parameters, and spatial and temporal variability.

Estimating nutrient releases from agriculture in China: An extended substance flow analysis framework and a modeling tool

Agriculture related pollution has attracted the attention of policy makers as well as scientists in China as its contribution to water impairment has increased, and quantitative information at the national and regional levels is being sought to support decision making. However, traditional approaches are either time-consuming, expensive (e.g. national surveys) or oversimplified and crude (e.g. coefficient methods). Therefore, this study proposed an extended substance flow analysis (SFA) framework to estimate nutrient releases from agricultural and rural activities in China by depicting the nutrient flows in Chinese agro-ecosystems. The six-step process proposed herein includes: (a) system definition; (b) model development; (c) database development; (d) model validation; (e) results interpretation; and (f) uncertainty analysis. The developed Eubolism (Elementary Unit based nutrient Balance mOdeLIng in agro-ecoSysteM) model combined a nutrient balance module with an emission inventory module to quantify the nutrient flows in the agro-ecosystem. The model was validated and then applied to estimate the total agricultural nutrient loads, identify the contribution of different agricultural and rural activities and different land use types to the total loads, and analyze the spatial pattern of agricultural nutrient emissions in China. These results could provide an entire picture of agricultural pollution at the national level and be used to support policy making. Furthermore, uncertainties associated with the structure of the elementary units, spatial resolution, and inputs/parameters were also analyzed to evaluate the robustness of the model results.

Development and identification of an integrated waterworks model for trihalomethanes simulation

To evaluate the impact that new trihalomethanes (THMs) regulations will have on the performance of conventional waterworks in China, we developed an integrated waterworks model to simulate the dynamic behavior of THMs and other associated components, e.g. organic matter, ammonia, and residual chlorine, throughout the conventional water treatment process, which included pre-chlorination, coagulation-flocculation, sedimentation, filtration and post-chlorination. A comprehensive kinetic scheme that takes into account both the physical and biological mechanisms involved in the water treatment processes and the chemical reactions that result from chlorination was proposed for model conceptualization. In addition, the Petersen matrix was designed to present the model and formulate the mass balance equations for the model variables. The model was then identified using the Hornberger-Spear-Young (HSY) algorithm and tested against field data from the Qingzhou Waterworks in Macao, China. Despite gross uncertainty associated with the field data, the model could generally provide good predictions of the simulated variables and meet the management purposes. Furthermore, the identified model parameters agreed well with values that were reported in the literature and could be reasonably interpreted.

Integrated assessment of China’s adaptive capacity to climate change with a capital approach

Although many impacts of climate change are difficult to discern due to successful adaptation and the influence of non-climatic drivers, the effects of climate change, particularly temperature rises, in various socio-economic systems have been increasingly documented (Parry 2007). Even if atmospheric greenhouse gas (GHG) concentrations were to remain at 2000 levels, past emissions are estimated to cause some unavoidable warming (Solomon et al. 2007). In reality, however, GHG emissions and concentrations continue to rise, locking us into further long-term climate change. Therefore improving adaptive capacity to deal with climatic variability and climate-related disasters is imperative for socio-economic systems that are increasingly challenged by the economic, social, health and environmental consequences of these changes. Climatic Change (2015) 128:367–380 DOI 10.1007/s10584-014-1163-7

Structure validation of an integrated waterworks model for trihalomethanes simulation by applying regional sensitivity analysis

A previously developed integrated waterworks model for trihalomethanes simulation was validated by applying a new framework for comprehensive model structure validation. The proposed framework followed the procedure of regional sensitivity analysis and also involved correlation analysis and frequency distribution analysis. Through such an analysis framework, a deep insight into model structure and parameters could be gained besides the traditional focuses on model validation, i.e. model performance and rationality of model parameters. The integrated waterworks model, to which the framework was applied, was proved to give good predictions of the simulated variables, and the identified values of model parameters coincided well with the reported values in the literature. The model was also found to have a large proportion of sensitive parameters, no distinct correlations among parameters, and thus a balanced structure. Moreover, most of the sensitive parameters could be well identified and the associated uncertainties significantly reduced. A detailed investigation into the sensitivity, identifiability, and uncertainty of model parameters showed that the model conceptualization was in good agreement with accepted scientific principles and anticipated system behaviors. All these results, therefore, supported the validity and trustworthiness of the model. In addition, further opportunities for refining the model were also proposed.

A stochastic optimization approach for integrated urban water resource planning

Urban water is facing the challenges of both scarcity and water quality deterioration. Consideration of nonconventional water resources has increasingly become essential over the last decade in urban water resource planning. In addition, rapid urbanization and economic development has led to an increasing uncertain water demand and fragile water infrastructures. Planning of urban water resources is thus in need of not only an integrated consideration of both conventional and nonconventional urban water resources including reclaimed wastewater and harvested rainwater, but also the ability to design under gross future uncertainties for better reliability. This paper developed an integrated nonlinear stochastic optimization model for urban water resource evaluation and planning in order to optimize urban water flows. It accounted for not only water quantity but also water quality from different sources and for different uses with different costs. The model successfully applied to a case study in Beijing, which is facing a significant water shortage. The results reveal how various urban water resources could be cost-effectively allocated by different planning alternatives and how their reliabilities would change.

Probabilistic ecological risk assessment of effluent toxicity of a wastewater reclamation plant based on process modeling.

The growing use of reclaimed wastewater for environmental purposes such as stream flow augmentation requires comprehensive ecological risk assessment and management. This study applied a system analysis approach, regarding a wastewater reclamation plant (WRP) and its recipient water body as a whole system, and assessed the ecological risk of the recipient water body caused by the WRP effluent. Instead of specific contaminants, two toxicity indicators, i.e. genotoxicity and estrogenicity, were selected to directly measure the biological effects of all bio-available contaminants in the reclaimed wastewater, as well as characterize the ecological risk of the recipient water. A series of physically based models were developed to simulate the toxicity indicators in a WRP through a typical reclamation process, including ultrafiltration, ozonation, and chlorination. After being validated against the field monitoring data from a full-scale WRP in Beijing, the models were applied to simulate the probability distribution of effluent toxicity of the WRP through Latin Hypercube Sampling to account for the variability of influent toxicity and operation conditions. The simulated effluent toxicity was then used to derive the predicted environmental concentration (PEC) in the recipient stream, considering the variations of the toxicity and flow of the upstream inflow as well. The ratio of the PEC of each toxicity indicator to its corresponding predicted no-effect concentration was finally used for the probabilistic ecological risk assessment. Regional sensitivity analysis was also performed with the developed models to identify the critical control variables and strategies for ecological risk management.

Integrated Model Driven by Agent-Based Water End-Use Forecasting to Evaluate the Performance of Water and Wastewater Pipeline Systems

AbstractIn spite of their hydraulic, temporal, and spatial connections, water and wastewater pipeline systems are traditionally planned and designed in a stationary and separated manner. This practice may have, in the early stages, already rooted future system operational risk. An integrated model was developed to evaluate the performance of these two systems, planned and designed according to the traditional water demand quota approaches adopted in China. The integrated model included an agent-based water end-use model to generate water demand and wastewater discharge, which was used to drive a water distribution system model and a drainage system model, both developed by the U.S. Environmental Protection Agency. In a case study in Beijing, the proposed model forecasted lower water demand and wastewater discharge, leading to oversized water systems designed by the traditional approach. However, the greater diurnal fluctuations would cause operational problems during the peak hour, as well as off-peak per...

Global progress in climate change adaptation policies and its implication for China

This paper reviews the progress in climate change adaptation (CCA) policies both under the United Nations Framework Convention on Climate Change (UNFCCC) and in major regions and countries, including the EU and its major member countries, the influential developed countries in the Asia-Pacific region, the emerging economies and the least developed countries (LDCs). The progress made in China in CCA policies is also reviewed and compared with that in other countries. Finally, good international practices are proposed for China’s policy development. It is found that adaptation has been given the same priority as mitigation since the twenty-first century with regard to climate change-related actions. The topics related to adaptation in the international climate change negotiations under the UNFCCC have evolved from mechanisms for finance and technology development and transfer exclusively in the early stages to implementation of practical adaptation programs and actions. Since 2006, major developed and developing countries have frequently set forward specific CCA policies or general climate change policies involving adaptation in the form of laws, frameworks, strategies, and plans. The LDCs have also been working on National Adaptation Programmes of Action and subsequent National Adaptation Plans with the support from the financial mechanisms under the UNFCCC. Therefore, globally, it has become a common practice to develop national or regional policies to plan and guide CCA actions. China has established climate change policies involving adaptation at the national, regional, and sectorial levels since 2007. However, these policies have strong limitations in their knowledge base, strategic positioning, contents, and implementation mechanisms, e.g. lack of a sound knowledge base, an international perspective, clear responsibilities for policy implementation, and appropriate monitoring and evaluation mechanisms. It is recommended that China should further strengthen its technical capabilities in climate change projections as well as impact, vulnerability, and risk assessment, and develop methodologies and techniques for the preparation, impact assessment and implementation of CCA policies. Furthermore, future CCA strategies or plans should be developed with an emphasis on China’s vision and strategic position on the world stage.

Integrated Management of Source Water Quantity and Quality for Human Health in a Changing World

Water is an essential life-sustaining element of daily life for each and every one. However, water crisis in both quantity and quality seemingly becomes inevitable in such a changing world in terms of the variation of global environment, the ever-growing population, and the serious environmental pollution. Both water quantity and quality are influenced by the natural conditions such as climate, geography, topography, and geology, and human activities such as water withdrawal, excreta and sanitation, agriculture, industry, mining, traffic and transportation, and waste disposal and landfill. The adverse effects that the human race has exerted on water sources have in turn threatened human health either by limiting good hygiene or by impairing drinking water safety. To cope with the water crisis, innovative approaches to source water management have been proposed all around the world from a holistic perspective, based on integration of multidisciplinary work and within a collaborative framework. Fortunately enough, with the development of water and wastewater treatment technology, alternative water sources, including desalination, rainwater harvesting, and water reuse, have been exploited to satisfy the thirsty world.