Abstract
The textile industry is one of the most intensive industries in chemical products whose wastewater contains hazardous dyes, pigments, dissolved/suspended solids, and heavy metals. Hence, it ...is important to effectively treat the wastewater generated by this industry before releasing it into the environment. Although the field of textile wastewater treatment has made tremendous progress, the developed treatment methods should be improved further to make them economically viable and friendly. In this review, characteristics of textile wastewater are introduced. We have primarily focused on the environmental impact and toxicity of textile wastewater. Toxic and harmful contaminants must be removed from textile wastewater to reduce the extent of environmental pollution caused when textile wastewater is released into rivers or reused. Hence, various techniques that are used to treat textile wastewater are discussed. Finally, the challenges faced, and prospects of the methods have been discussed in detail.
With increasing PV penetration level, performances of the distributed grid-connected PV system and aggregated effects on public grid need to be identified and analyzed. This paper simulated the ...techno-economic performances of the grid-connected residential PV-battery system based on simulated PV generations, history household load, technical and economical parameters under the electricity market in Kyushu, Japan. Results indicate that residential PV self-consumption ratios vary significantly between months, it can increase by adding relative battery size, the increasing rate shows obvious variations between months and its value highly depends on features of the customer load and PV generation profiles. Optimal management strategies for private home storage dispatch show a potential in grid peak load shaving. Assumed accumulative generation of home PV-battery system totally shares 2.0% of grid load, analysis indicates that proposed grid-supporting PV-battery systems can participate in 1.1% reduction of peak grid load. The economic feasibility and uptake of battery system highly depend on direct subsidies due to high capacity cost, payback period of PV-battery system is around 18 years without any incentive policies. Increasing electricity pricing, decreasing PV feed-in tariff and falling cost in battery can provide the home PV-battery system more attractiveness.
•Self-consumption rate and self-sufficiency degree show great variations between months.•Analysis of PV self-consumption ratio by adding different relative battery sizes.•Aggregated optimized residential PV-battery system can release the public grid pressure.•Incentive subsidy to battery unit is essential to shorten the payback period of PV-battery system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In the last decade, technological innovations and a changing economic and regulatory environment have resulted in a renewed interest for distributed energy resources (DER). However, because of the ...lack of a suitable design tool, the expected potential of DER penetration is not always exerted sufficiently. In this paper, a mixed-integer linear programming (MILP) model has been developed for the integrated plan and evaluation of DER systems. Given the site’s energy loads, local climate data, utility tariff structure, and information (both technical and financial) on candidate DER technologies, the model minimizes overall energy cost for a test year by selecting the units to install and determining their operating schedules. Furthermore, the economic, energetic and environmental effects of the DER system can be evaluated. As an illustrative example, an investigation has been conducted of economically optimal DER system for an eco-campus in Kitakyushu, Japan. The result illustrates that gas engine is currently the most popular DER technology from the economic point of view. Although holding reasonable economic merits, unless combined with heat recovery units, the introduction of DER technologies may result in marginal or even adverse environmental effects. Furthermore, according to the results of sensitivity analysis, the optimal system combination and corresponding economic and environmental performances are more or less sensitive to the scale of energy demand, energy prices (both electricity and city gas), as well as carbon tax rate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To deal with increasing energy consumption in the residential sector, distributed energy resources including photovoltaic (PV), fuel cell, etc. have been paid more and more attention. In this study, ...an optimization model is developed for the PV/Fuel Cell/Battery based residential energy system. While guaranteeing reliable system operation, the model may determine the optimal running strategies with annual running cost or annual CO2 emissions as the objective function to be minimized. In addition, besides the energy flows among the equipments within the hybrid energy system, the economic information including electricity tariff and natural gas price, as well as some policy issues (e.g., buy-back price) are also accounted. As the results of the model, besides the optimal electric and thermal balances, the rational utilization forms of PV module, fuel cell and battery can be also deduced. To verify the viability of the proposed approach, a numerical example is implemented and analyzed. The optimal operating strategies are deduced and compared from different perspectives. Furthermore, the results demonstrate that the PV module mainly contributes to the environmental performance of the assumed hybrid energy system, while the battery may be beneficial from the economic viewpoint.
•An optimization model is developed for a hybrid PV/fuel cell/battery energy system.•Both economic and environmental objective functions have been considered.•The PV module mainly contributes to the environmental performance.•The battery bank may be beneficial from the economic point of view.•Both battery size and buy-back price may influence the system performances.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
To address the primary energy shortage problem, Japan has implemented a series of policies and measures for residential energy conservation and emission reduction. Among them, the home energy ...management system (HEMS) as a hub connecting users and power companies to realize energy visualization has been widely studied. The research object of this study is a two-story detached residence integrated with HEMS in the “Jono Zero Carbon Smart Community” in Japan. To predict the energy consumed on the next day based on historical data, a short-term household load forecasting model based on the particle swarm optimization regression vector machine algorithm was developed. Then a dynamic pricing model was developed to guide the users’ electricity consumption behavior and adjust the grid load. According to the prediction results obtained by the load forecasting model, the annual electricity charges of users under the three pricing schemes of multistep electricity pricing (MEP), time-of-use pricing (TOU), and real-time pricing (RTP) were calculated and compared. The result indicated that the annual electricity cost generated by RTP was less than those generated by MTP and TOU. In addition, after adjusting the users’ peak load and combining it with the fluctuating future electricity prices, RTP presented evident economic advantage over MTP and TOU in terms of the annual electricity cost of the users. The study results can provide policy suggestions for the future Japanese government’s promotion of RTP strategy, while acting as a reference for further developing the characteristics of HEMS and optimizing the relation between the supply and demand sides.
•A short-term forecasting model suitable for household load is established based on PSO-RVM algorithm.•A real-time price (RTP) model is proposed to guide the use behaviors and balance the grid load.•RTP has economic advantages over TOU and MTP under different price schemes.•RTP has a great potential to combine with demand side response and future price fluctuation.•Results can promote RTP and application of HEMS to optimize the relationship between supply and demand.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The growing worldwide demand for less polluting forms of energy has led to a renewed interest in the use of micro combined heat and power (CHP) technologies in the residential sector. The operation ...of micro CHP system results in simultaneous production of heat and power in a single household based on small energy conversion units. The heat produced may be used for space and water heating and possibly for cooling load if combined with an absorption chiller, the electricity is used within the house.
In this paper, two typical micro CHP alternatives, namely, gas engine and fuel cell for residential buildings, are analyzed. For each facility, two different operating modes including minimum-cost operation and minimum-emission operation are taken into consideration by employing a plan and evaluation model for residential micro CHP systems. The analysis results show that the fuel cell system is recognized as a better option for the examined residential building from both economic and environmental points of view. With the operation considering optimal economic benefits, annual energy cost is reduced by about 26%. On the other hand, while maximizing the environmental merits, annual CO
2 emissions are reduced by about 9%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Water resources are essential for production and life of human beings, as well as urban economy and social development. At present, shortage of water resource has been emerging one of the urgent ...problems that many cities in China are facing due to rapid urbanization. In this work, water ecological footprint method has been applied to demonstrate how the sustainable utilization of water resources can be realized. According to the basic principle and calculation model of water ecological footprint, the water ecological footprint (WEF) and water ecological carrying capacity (WEC) in a period of 2004–2015 in Beijing, Shanghai, Tianjin, and Chongqing were analyzed. Then, the water ecological footprints per capita were predicted with the quadratic exponential smoothing in 2020 and 2025, respectively. The results show that the total WEF in these cities except for Shanghai increased from 2004 to 2015. The productive WEF was the primary consumption account in the total WEF accounts of the four cities. In 2015, the productive WEFs of Beijing, Shanghai, Tianjin, and Chongqing accounted for 54.46%, 82.61%, 75.04%, and 80.03% of total WEF amounts, respectively. At the same time, the proportion of the WEF of tertiary industry in Beijing was as high as 50.14% in the productive WEF accounts. The biggest proportion of the WEF of secondary industry was 59.14% and 53.14% in Shanghai and Chongqing, respectively. In Tianjin, the WEF of primary industry was the biggest proportion, accounting for 65.03%. In terms of the WEF per capita, we also found that the water ecological surplus per capita for Tianjin occurred only in 2012 indicating serious water ecological deficit in the other years. While the water ecological deficit per capita occurred in Shanghai before 2014 and exited in Beijing in the whole study period, which suggested that water resource utilization was not sustainable. However, the WEC per capita in Chongqing was bigger than the WEF per capita during 2004–2015, contributing to the water ecological surplus per capita in Chongqing. That is to say, the sustainable utilization of water resources in Chongqing was rational. It is evidenced that such changes of the total WEF are closely related to the productive WEF. We thus suggest that the productive structure associated with the distribution of water resources in different cities should be manipulated towards improving the WEC, reducing the WEF and fix regional water imbalance for further promoting the sustainable development of the overall socio-economy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Rural energy consumption is an important component of national energy consumption and plays an important role in rural areas and ecological environment developments. This paper investigated energy ...structure and energy usage behavior in rural areas of northern China based on the analysis of large-scale field survey data. The energy consumption structure is composed of the biomass energy and commercial energy, supplemented by two kinds of mutual use of the way. And Low efficient energy usage and poor indoor environment are major problems in this area. Therefore, the reason for the excessive energy consumption is poor thermal performance of construction, lack of planning standards and low energy efficiency. This paper provides new insights for north China's rural energy consumption, it can also provide detail and real data for the local decision makers and other stakeholders to promote energy-saving policy.
•Analysis of energy usage behavior in rural areas in northern China based on large-scale field survey data.•Inefficient energy usage, poor indoor thermal and air quality are major problems in rural of northern China.•Geographical differences represent the main cause of different levels of the RHEC.•Present five energy-saving measures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Four polysaccharides BJP50, BJP60, BJP70 and BJP80 (total named BJPs) were separated from Herba Patriniae via gradient ethanol precipitation with 50%, 60%, 70% and 80%, respectively. After ...decolorization and deproteinization, their physicochemical features and antioxidant activities were investigated. The results showed that the total sugar content of BJPs accounted above 50% but no protein contained, while BJP50 and BJP60 contained a small amount of uronic acid. GC analysis indicated that BJPs were mainly composed of galactose, arabinose, glucose, mannose, xylose and rhamnose. From BJP50 to BJP80, the types of monosaccharides and the content of arabinose, glucose and mannose increased but that of galactose and rhamnose decreased, and their molecular weights gradually reduced from 2.3 × 106 to 4.5 × 103. BJPs had a good thermal stability with the order of BJP80 > BJP70 > BJP60 > BJP50. The vitro bioactivity assay showed that BJP80 and BJP70 exhibited stronger scavenging capacities for DPPH, ABTS and hydroxyl free radicals than that of BJP60 and BJP50. As the concentration reached 4 mg/mL, the scavenging capacities of BJP80 and BJP70 on DPPH and hydroxyl free radical were up to 92% and 95%, respectively, and their antioxidant activities gradually approached to the positive control.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In 2012, the Japanese government launched the new Feed-In Tariff Act (FIT), which aimed at promoting the stable, integrated rise of renewable energy in the wake of the Fukushima nuclear accident. ...Solar photovoltaic (PV) energy on both the residential (installation capacity less than 10 kW) and non-residential side (installation capacity 10 kW and above) has been associated with significant benefits with the passage of the new FIT Act. However, a number of issues have emerged during implementation, including unjust enrichment from delayed PV plant operation and high renewable energy taxes. In this paper, we present an overview of the evolution of the FIT and explore how the relevant issues have been addressed through revised government policy. The paper also examines, the FIT’s effect on PV energy development. An economic analysis was conducted to identify the impact of FIT fixed price changes on the profitability of solar PV plants on both the residential and non-residential side from 2012 to 2019. Furthermore, a sensitivity analysis was conducted based on scenarios of future FIT fixed purchase price reductions and PV initial investment cost reductions. The results show that the FIT can potentially be reduced on the residential side and that the current FIT has reached its feasibility limits in terms of non-residential PV investments.
•Overview of the evolution of the new FIT Act in Japan.•The FIT’s effect on PV deployment and cost reduction in Japan are discussed.•Economic analysis to measure FIT’s effect on PV plants of different sizes in Japan.•Sensitivity analysis to examine the effect of varying FIT on PV plants feasibility.•Detailed policy recommendations to improve the FIT Act of PV energy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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