Life cycle comparison of hydrothermal liquefaction and lipid extraction pathways to renewable diesel from algae

Algae biomass is an attractive biofuel feedstock when grown with high productivity on marginal land. Hydrothermal liquefaction (HTL) produces more oil from algae than lipid extraction (LE) does because protein and carbohydrates are converted, in part, to oil. Since nitrogen in the algae biomass is incorporated into the HTL oil, and since lipid extracted algae for generating heat and electricity are not co-produced by HTL, there are questions regarding implications for emissions and energy use. We studied the HTL and LE pathways for renewable diesel (RD) production by modeling all essential operations from nutrient manufacturing through fuel use. Our objective was to identify the key relationships affecting HTL energy consumption and emissions. LE, with identical upstream growth model and consistent hydroprocessing model, served as reference. HTL used 1.8 fold less algae than did LE but required 5.2 times more ammonia when nitrogen incorporated in the HTL oil was treated as lost. HTL RD had life cycle emissions of 31,000 gCO₂ equivalent (gCO₂e) compared to 21,500 gCO₂e for LE based RD per million BTU of RD produced. Greenhouse gas (GHG) emissions increased when yields exceeded 0.4 g HTL oil/g algae because insufficient carbon was left for biogas generation. Key variables in the analysis were the HTL oil yield, the hydrogen demand during upgrading, and the nitrogen content of the HTL oil. Future work requires better data for upgrading renewable oils to RD and requires consideration of nitrogen recycling during upgrading.     

Gini coefficient to assess equity in domestic water supply in the Yellow River

Yellow River, is designated as “the cradle of Chinese civilization” and played a key role not only in the country’s economic development but also in the historic and cultural identity of the Chinese people. With the rapid economic development and population growth, water demand for industry and households has increased significantly in the Yellow River basin; this has caused an increasing gap between water supply and demand. Competing water demands triggered conflicts between disparate water users on different scales such as the rich and the poor, or between different sectors and regions, such as domestic and agriculture, agriculture and industry, upstream and downstream, rural and urban areas, etc. Ensuring equity in water supply for conflicting water users is one of the major challenges that facing water managers and in particular water management in the Yellow River basin. In this paper, a method has been developed to calculate the Gini coefficient of water use as an indicator to measure the equality in domestic water supply. A dual domestic water use structure model is employed for this purpose. The developed method is subsequently applied to assess the equality in domestic water supply in the Yellow River. Data of population growth, domestic water use and economic development over the time period 1999-2006 are used to calculate the Gini coefficient of water use over the same length of period. The result shows a decreasing trend in Gini coefficient of domestic water use in the Yellow River basin after 2001 which means domestic water use is becoming more and more equitable in the basin. The study justifies that the Gini coefficient of water use can be used and recommended as a useful tool for the water management especially in the context of global change.     

Water resources planning and management based on system dynamics: a case study of Yulin city

Water security is an integral aspect of the socio-economic development in China. Nevertheless, water resources are under persistent pressures because of the growing population, heavy irrigation, climate change effects and short-term policies. Traditional management approaches narrowly focus on increasing supply and reducing demand without considering the complex interactions and feedback loops that govern water resource behaviour. Whereas these approaches may provide quick fix solutions, they often lead to unanticipated, sometimes catastrophic, delayed outcomes. Therefore, water management needs to take a holistic approach that caters to the interdependent physical (e.g. water inflows, outflows) and behavioural (e.g. decision rules, perceptions) processes in the system. Unlike reductionist approaches, System Dynamics (SD) takes a system-level view for modelling and analysing the complex structure (cause–effect relationships, feedback loops, delays) that generates the systemic behaviour. Simulating the SD model allows assessing long-term system-wide impacts, exploring leverage points and communicating results to decision makers. In this paper, we follow an SD modelling approach to examine the future of water security in Yulin City. First, we present a conceptual model for integrating water supply and demand. Based on this, we build an SD model to simulate and analyse the dynamics of water resource over time. The model output is tested to ensure that it satisfactorily replicates the historical behaviour of the system. The model is used to quantitatively assess the effectiveness of various supply/demand management options. Three scenarios are designed and examined: business-as-usual, supply management, and demand management. Results show that current management regime cannot effectively meet the future water demand. Whereas supply acquisition provides short-term benefits, it cannot cope with the growing population. A combination of conservation measures and demand-management instruments is regarded the most effective strategy for balancing supply and demand.     

Water resources management strategy for adaptation to droughts in China

Water Scarcity and drought are recurrent phenomena in China. In the context of environmental change, an increasing tendency in drought frequency and severity is observed in China in recent years. Therefore, it is imperative to take necessary initiatives to reduce the impacts of drought. In this paper, an attempt is made to identify the best water management strategies to cope with droughts. For this objective the records of historical droughts and their impacts in China over the period of 1950?C2009 are analyzed. It is observed that the drought affected area has increased nearly by 12 folds and the drought damaged area has increased by about 22 times in China in last 60?years. Over 87,000 reservoirs were built with a total water storage capacity of about 7,064 billion m³ to cope with droughts. However, this structural supply-based management strategy was not enough to meet the increasing water demand caused by rapid economic development and population growth. A typical relationship between socio-economic development and water resources management strategy to attain sustainability in water management is developed in this study. The relationship shows that the demand-side water management strategies can be the best option to meet the challenges posed by increased severity of drought, population growth, economic development and possible climate change. The concept is later verified through the analysis of changing pattern of water consumptions by different sectors in last 60?years.     

Environmental flows and its evaluation of restoration effect based on LEDESS model in Yellow River Delta wetlands

Due to freshwater supplement scarcity and heavy human activities, the fresh water wetland ecosystem in Yellow River Delta is facing disintegrated deterioration, and it is seriously affecting the health of the Yellow River ecosystem. This paper identifies the restoration objectives of wetland aiming to protect ecological and economic values and development as well as the water resources of the Yellow River. The hydraulic and groundwater coupling model and Landscape Ecological Decision and Evaluation Support System (LEDESS) of the Yellow River Delta were established to calculate environmental flows of degraded wetlands. LEDESS is a computer-based model developed and used to assess and evaluate the effects of land-use changes on nature. In this study, LEDESS is used to assess and evaluate the ecological effects and the restoration possibilities considering several environmental flows’ supplement scenarios. This included the changes of suitable habitat conditions and its ecological carrying capacities for indicator species, e.g., Red-crowned crane (Grus japonensis), Oriental stork (Ciconia boyciana), and Saunder’s gull (Larus relictus), and changing of ecological patterns. The results showed that replenishing fresh water to wetlands is one of the effective adaptive measures to mitigate wetland degradation and improve its habitat quality and carrying capacities. This study indicated that landscape ecology approach is not only considered as a good way to solve complex problems in ecosystem management but also can be used to decide on the environmental flows and assess its ecological effects in large-scale wetland rehabilitation. This integrated method could make environmental flows estimated and assessment more rational than the results of hydrologic methods. It could assist decision makers to “see” the ecological effects after water supplementing and so alleviate the contradictions between environmental flows and production water demands, and can facilitate the implementation of environmental flows in most countries with water resources shortage.     

Using system dynamics to model water-reallocation

Improving the efficiency of water allocation has long been recognised as a key problem for the water resources management decision-makers. However, assessing the efficacy of management decision is difficult due to the complexity and interconnectivity of water resource systems. For this reason, it is vital that robust modelling approaches are employed to deal with the feedback loops inherent in the water resource systems. Whilst many studies have applied modelling to various aspects of water resource management, little attention has been given to innovations in modelling approaches to deal with the modelling challenges associated with improving decision-making. The aim of this study is to apply a System Dynamics modelling approach to improve the efficiency of water allocation incorporating a myriad of irrigation system constraints. The system dynamic approach allows the different system components to be organised as a collection of discrete objects that incorporate data, structure and function to generate complex system behaviour. Through the application of a system dynamic approach, a robust model (named the Economical Reallocating Water Model (ERWM)) was developed which was used to examine the options of re-allocating water resources that minimize the water cost all over an irrigated agricultural area. The EWRM incorporated a wide range of complexities likely to be encountered in water resource management: surface and ground water sources, water trading between sources, system constraint such as maximum ground water pumping, rates, maximum possible trading volumes and differential water resource prices. Two hypothetical systems have been presented here as an example. The results show that the System Dynamics approach has a significant advantages in estimating and assessing the outcomes of alternative water management strategies through time and space.     

A strategy to deal with water crisis under climate change for mainstream in the middle reaches of Yellow River

Our planet is increasingly threatened by degradation in water quantity and quality due to climate change, population growth and development pressures. Water shortage is one of the most challenging environmental problems to humankind in the 21st century under the changing climate. Water shortages and scarcity escalate risks to food security and economic viability. For decades, water management has been dominated by supply oriented paradigm of expanding the capacity of accessible water (e.g. building dams). While large scale infrastructure projects provided effective solutions for chronic water crises in the past, they have come at expensive, irreversible and delayed ecological, economic and social costs. As more questions are raised concerning over reliance on infrastructure solutions, discussions about a sustainable future suggest a greater focus on the demand side of the equation is needed. In this paper, we use multi-recursive and runoff coefficient analysis methods to analyze the annual runoff of the mainstreams (Kuye River, Tuwei River, Wuding River and Jialu River) in the middle reaches of Yellow River. The main objective is to estimate the impacts of climate change and human activity on water resources in the study area and test the potential of water demand management to lessen the gap between supply and demand. Results show remarkable drop in the average annual runoff as a combined effect of climate change and human activity. Moreover, results show that human activities are the direct reason for the changes of river runoff, and the proportion of human activities account the biggest is Wuding river, next is Kuye river, Jialu river is smallest, these changes lead to the decrease of river runoff, and even drying up in recent years. This result highlights the importance of using WDM to diminish the increasing gap between demand and supply. Motivated by this, the paper presents a comprehensive framework for implementation WDM in the middle reaches of Yellow River. The framework includes a wide range of instruments: legislative, economic, technological and educational. The core step of the framework, collaboration among water planners, water service providers and end-users lies as an essential mechanism for achieving long term trade-offs between ecological and socio-economic water needs.     

Forecasting industrial water demand in Huaihe River Basin due to environmental changes

A framework is proposed for forecasting industrial water demand in the context of climate change, economic growth, and technological development. The framework was tested in five sub-basins of Huaihe River of China, namely Upstream of Huaihe River (UH), Middlestream of Huaihe River (MH), Downstream of Huaihe River (DH), Yishusi River (YSSR), and Coastal River of Shandong Peninsula (CSP) to project future changes in industrial water demand under different environment change scenarios. Results showed that industrial water demand in Huaihe River basin will increase in the range of 10 to 44.6% due to economic development, water-saving technological advances, and climate change. The highest increase was projected by general circulation model (GCM) BCC-CSM1–1 (179.16 × 108 m³) and the lowest by GCM GISS-E2-R (132.4 × 10⁸ m³) in 2020, while the GCM BNU-ESM projected the highest increase (190.57 × 10⁸ m³) and GCM CNRM-CM5 the lowest (160.41 × 10⁸ m³) in 2030. Among the different sub-basins, the highest increase was projected in MH sub-basin where industrial water demand is already very high. On the other hand, the lowest increase in industrial water demand was projected in UH sub-basin. The rapid growth of high water-consuming industries and increased water demand for cooling due to temperature rise are the major causes of the sharp increase in industrial water demand in the basin. The framework developed in the study can be used for reliable forecasting of industrial water demand which in turn can help in selection of an appropriate water management strategy for adaptation to global environmental changes.     

Development of a GIS tool for qualitative assessment of the Egyptian’s quality of life

A frame work was presented for the assessment of the quality of life through the development of different indicators applied for Egypt. This paper focuses on the assessment of the quality of life using previously developed indicators in the first part of the study. A GIS user-friendly interface was developed to enhance the presentation of the study. This enables non technical users to directly use the developed GIS application to explore different concerns. Three cases were demonstrated in this paper, where an assessment of the quality of life of farmers, civilians, and agricultural investors was attained under specific scenario in each case. Assessment for other cases can still be made by browsing through the dropdown menu for each interest group under the selected scenario. Based on the demonstrated results for the three groups of people, it was found that the quality of life for a certain group of people under the strict scenario is in general less than the quality of life for the same group under the relax scenario.     

Climate change and water resources management in Tuwei river basin of Northwest China

Water resources are an integral part of the socio-economic-environmental system. Water resources have dynamic interactions with related social, economic and environmental elements, as well as regulatory factors that are characterized by non-linear and multi-loop feedbacks. In this paper, a complex System Dynamic (SD) model is used to study the relationship among population growth, economic development, climate change, management strategies and water resources, and identify the best management strategy to adapt with the changing environment in the Tuwei river basin of Northwest China. Three management alternatives viz. business as usual, water supply management and water demand management are studied under different climate change scenarios. Results indicate that water shortage rate in Tuwei river basin may increase up to 80 % by the year 2030 if current management practices are continued or the supply based management strategy is adopted. On the other hand, water demand management can keep the water shortage rate within a tolerable limit and therefore can be considered as the sustainable strategy for water resources management to maintain the economic growth and ecological status of the Tuwei river basin.