Over 17% Efficiency Stand‐Alone Solar Water Splitting Enabled by Perovskite‐Silicon Tandem Absorbers

Realizing solar‐to‐hydrogen (STH) efficiencies close to 20% using low‐cost semiconductors remains a major step toward accomplishing the practical viability of photoelectrochemical (PEC) hydrogen generation technologies. Dual‐absorber tandem cells combining inexpensive semiconductors are a promising strategy to achieve high STH efficiencies at a reasonable cost. Here, a perovskite photovoltaic biased silicon (Si) photoelectrode is demonstrated for highly efficient stand‐alone solar water splitting. A p⁺nn⁺ ‐Si/Ti/Pt photocathode is shown to present a remarkable photon‐to‐current efficiency of 14.1% under biased condition and stability over three days under continuous illumination. Upon pairing with a semitransparent mixed perovskite solar cell of an appropriate bandgap with state‐of‐the‐art performance, an unprecedented 17.6% STH efficiency is achieved for self‐driven solar water splitting. Modeling and analysis of the dual‐absorber PEC system reveal that further work into replacing the noble‐metal catalyst materials with earth‐abundant elements and improvement of perovskite fill factor will pave the way for the realization of a low‐cost high‐efficiency PEC system.     

TriboPump: A Low‐Cost,Hand‐Powered Water Disinfection System

Water disinfection at the point of use (POU) has enormous social and economic significance, especially for rural areas or catastrophes. To tackle the requirements of power independence and cost control in such applications, the concept of TriboPump is proposed, which is a low‐cost, hand‐powered water disinfection system. The system consists of three functional parts: a tubular coaxial‐electrode copper ionization cell (CECIC) as the disinfection device, a disk triboelectric nanogenerator (D‐TENG) as the power source, and a coaxial mechanical structure including the water pump. The adoption of D‐TENG can make the system adaptive to varying system resistances without additional power management circuits. Moreover, the integration of CECIC and TENG can successfully turn their intrinsic limitations into advantages and a synergic effect is achieved. With the integrated design, the system can effectively disinfect the water while pumping it solely by hand power. The cost estimate of the whole system can be as low as $10 for a 2‐year service. It is believed that the whole system design provides a feasible one‐stop and cost‐efficient solution for POU water pumping and disinfection, which will ideally be suitable the rural areas or sudden‐onset catastrophes.     

Net Zero Fort Carson: Integrating Energy,Water, and Waste Strategies to Lower the Environmental Impact of a Military Base

Military bases resemble small cities and face similar sustainability challenges. As pilot studies in the U.S. Army Net Zero program, 17 locations are moving to 100% renewable energy, zero depletion of water resources, and/or zero waste to landfill by 2020. Some bases target net zero in a single area, such as water, whereas two bases, including Fort Carson, Colorado, target net zero in all three areas. We investigated sustainability strategies that appear when multiple areas (energy, water, and waste) are integrated. A system dynamics model is used to simulate urban metabolism through Fort Carson's energy, water, and waste systems. Integrated scenarios reduce environmental impact up to 46% from the 2010 baseline, whereas single‐dimension scenarios (energy‐only, water‐only, and waste‐only) reduce impact, at most, 20%. Energy conserving technologies offer mutual gains, reducing annual energy use 18% and water use 15%. Renewable energy sources present trade‐offs: Concentrating solar power could supply 11% of energy demand, but increase water demand 2%. Waste to energy could supply 40% of energy demand and reduce waste to landfill >80%, but increase water demand between 1% and 22% depending on cooling system and waste tonnage. Outcomes depend on how the Fort Carson system is defined, because some components represent multiple net zero areas (food represents waste and energy), and some actions require embodied resources (energy generation potentially requires water and off‐base feedstock). We suggest that integrating multiple net zero goals can lead to lower environmental impact for military bases.     

Alternatives for natural‐gas‐based heating systems: A quantitative GIS‐based analysis of climate impacts and financial feasibility

The heating of buildings currently produces 6% of global greenhouse gas emissions. Sustainable heating technologies can reduce heating‐related CO₂ emissions by up to 90%. We present a Python‐based GIS model to analyze the environmental and financial impact of strategies to reduce heating‐related CO₂ emissions of residential buildings. The city‐wide implementation of three alternatives to natural gas are evaluated: high‐temperature heating networks, low‐temperature heating networks, and heat pumps. We find that both lowering the demand for heat and providing more sustainable sources of heat will be necessary to achieve significant CO₂‐emission reductions. Of the studied alternatives, only low‐temperature heating networks and heat pumps have the potential to reduce CO₂ emissions by 90%. A CO₂ tax and an increase in tax on the use of natural gas are potent policy tools to accelerate the adoption of low‐carbon heating technologies.     

Renewable jet fuel supply scenarios in the European Union in 2021–2030 in the context of proposed biofuel policy and competing biomass demand

This study presents supply scenarios of nonfood renewable jet fuel (RJF) in the European Union (EU) toward 2030, based on the anticipated regulatory context, availability of biomass and conversion technologies, and competing biomass demand from other sectors (i.e., transport, heat, power, and chemicals). A cost optimization model was used to identify preconditions for increased RJF production and the associated emission reductions, costs, and impact on competing sectors. Model scenarios show nonfood RJF supply could increase from 1 PJ in 2021 to 165–261 PJ/year (3.8–6.1 million tonne (Mt)/year) by 2030, provided advanced biofuel technologies are developed and adequate (policy) incentives are present. This supply corresponds to 6%–9% of jet fuel consumption and 28%–41% of total nonfood biofuel consumption in the EU. These results are driven by proposed policy incentives and a relatively high fossil jet fuel price compared to other fossil fuels. RJF reduces aviation‐related combustion emission by 12–19 Mt/year CO₂‐eq by 2030, offsetting 53%–84% of projected emission growth of the sector in the EU relative to 2020. Increased RJF supply mainly affects nonfood biofuel use in road transport, which remained relatively constant during 2021–2030. The cost differential of RJF relative to fossil jet fuel declines from 40 €/GJ (1,740 €/t) in 2021 to 7–13 €/GJ (280–540 €/t) in 2030, because of the introduction of advanced biofuel technologies, technological learning, increased fossil jet fuel prices, and reduced feedstock costs. The cumulative additional costs of RJF equal €7.7–11 billion over 2021–2030 or €1.0–1.4 per departing passenger (intra‐EU) when allocated to the aviation sector. By 2030, 109–213 PJ/year (2.5–4.9 Mt/year) RJF is produced from lignocellulosic biomass using technologies which are currently not yet commercialized. Hence, (policy) mechanisms that expedite technology development are cardinal to the feasibility and affordability of increasing RJF production.     

Challenges and opportunities for hydrogen production from microalgae

The global population is predicted to increase from ~7.3 billion to over 9 billion people by 2050. Together with rising economic growth, this is forecast to result in a 50% increase in fuel demand, which will have to be met while reducing carbon dioxide (CO₂) emissions by 50–80% to maintain social, political, energy and climate security. This tension between rising fuel demand and the requirement for rapid global decarbonization highlights the need to fast‐track the coordinated development and deployment of efficient cost‐effective renewable technologies for the production of CO₂ neutral energy. Currently, only 20% of global energy is provided as electricity, while 80% is provided as fuel. Hydrogen (H₂) is the most advanced CO₂‐free fuel and provides a ‘common’ energy currency as it can be produced via a range of renewable technologies, including photovoltaic (PV), wind, wave and biological systems such as microalgae, to power the next generation of H₂ fuel cells. Microalgae production systems for carbon‐based fuel (oil and ethanol) are now at the demonstration scale. This review focuses on evaluating the potential of microalgal technologies for the commercial production of solar‐driven H₂ from water. It summarizes key global technology drivers, the potential and theoretical limits of microalgal H₂ production systems, emerging strategies to engineer next‐generation systems and how these fit into an evolving H₂ economy.     

Competition for water for the food system

Although the global agricultural system will need to provide more food for a growing and wealthier population in decades to come, increasing demands for water and potential impacts of climate change pose threats to food systems. We review the primary threats to agricultural water availability, and model the potential effects of increases in municipal and industrial (M&I) water demands, environmental flow requirements (EFRs) and changing water supplies given climate change. Our models show that, together, these factors cause an 18 per cent reduction in the availability of worldwide water for agriculture by 2050. Meeting EFRs, which can necessitate more than 50 per cent of the mean annual run-off in a basin depending on its hydrograph, presents the single biggest threat to agricultural water availability. Next are increases in M&I demands, which are projected to increase upwards of 200 per cent by 2050 in developing countries with rapidly increasing populations and incomes. Climate change will affect the spatial and temporal distribution of run-off, and thus affect availability from the supply side. The combined effect of these factors can be dramatic in particular hotspots, which include northern Africa, India, China, parts of Europe, the western US and eastern Australia, among others.     

Estimation of Life Cycle Material Costs of Cadmium Telluride– and Copper Indium Gallium Diselenide–Photovoltaic Absorber Materials based on Life Cycle Material Flows

Chalcogenide and chalcopyrite photovoltaic (PV) technologies are highly suitable for solar energy conversion because of their high efficiency, long‐term stable performance, and low‐cost production. However, the absorber materials that are used, such as indium, gallium, and tellurium, are regarded as critical, and their limited availability can hinder market expansion. Therefore, we assess how material efficiency measures along the PV module's life cycle can reduce the net material demand of the absorber materials and thus the material costs. In order to estimate the material flows, we developed a closed‐loop model for the life cycle representing the phases module production, module collection, module recycling, and refinement. In order to reflect the variety and uncertainty in each phase, we compose three different efficiency scenarios by varying material efficiency measures on process and product levels. For each scenario, we compute the life cycle material costs based on the computed material flows. The results show that, in the long term, the material demand can be reduced down to one fourth of the required feedstock for module manufacturing; that is, three fourths of the absorber material stays in the life cycle in a very efficient scenario. Thus, total material costs along the life cycle could be significantly reduced, because the costs for material recycling are lower than the costs for “new” technical‐grade material. This reduction in life cycle material costs means that cadmium telluride– and copper indium gallium diselenide–PV can still be financially viable even if the price of the absorber materials increases significantly. Hence those technologies will still be competitive against crystalline silicon PV in the mid to long term.     

北疆地区棉花作物需水量时空演变及其气象影响因子

基于北疆25个气象站1961—2013年的气象资料和棉花生育期资料,利用 FAO 推荐的 Penman-Monteith 公式及作物系数法,对棉花各生育阶段的作物需水量和灌溉需水量进行估算.结果表明: 过去53年,北疆地区棉花需水量在各个生育期总体呈下降趋势,其中,花铃期作物需水量下降趋势最为显著,变化率为-0.15 mm·a^-1;各生育期内存在多尺度的周期变化,其中在30年左右的大周期尺度上,各生育期作物需水量大致呈现“偏高-偏低-偏高”的变化过程,在15～17年的中周期尺度上,经历了“偏低-偏高-偏低”的变化过程,而在较小年际尺度上,作物需水量无明显的周期特征;在空间分布上,作物需水量、灌溉需水量和水分盈亏指数多年均值总体上大致呈现自西向东递减的分布特征;突变结果显示作物需水量在各生育期均呈显著减少趋势,且在北疆西北和西南地区最为明显.各个生育期内,棉花需水量与平均风速、日照时数和平均气温都呈显著正相关,与相对湿度呈显著负相关.研究结果可为北疆棉花适时定量灌溉和提高水分利用效率提供基础数据支撑.     

Life Cycle Assessment of Water Supply Plans in Mediterranean Spain

Life cycle assessment (LCA) was used to compare the current water supply planning in Mediterranean Spain, the so‐called AGUA Programme, with its predecessor, the Ebro river water transfer (ERWT). Whereas the ERWT was based on a single interbasin transfer, the AGUA Programme excludes new transfers and focuses instead on different types of resources, including seawater and brackish water desalination and wastewater reuse, among others. The study includes not only water supply but the whole anthropic cycle of water, from water abstraction to wastewater treatment. In addition to standard LCA impact categories, a specific impact category focusing on freshwater resources is included, which takes into account freshwater scarcity in the affected water catchments. In most impact categories the AGUA Programme obtains similar or even lower impact scores than ERWT. Concerning impacts on freshwater resources, the AGUA Programme obtains an impact score 49% lower than the ERWT. Although the current water planning appears to perform better in many impact categories than its predecessor, this study shows that water supply in Spanish Mediterranean regions is substantially increasing its energy intensity and that Mediterranean basins suffer a very high level of water stress due to increasing demand and limited resources.     

The economics of producing sustainable aviation fuel: a regional case study in Queensland,Australia

The airline industry has a strong interest in developing sustainable aviation fuels, in order to reduce their exposure to increasing oil prices and cost liability for greenhouse gas emissions. The feasibility and cost of producing sustainable biomass‐based jet fuels at a sufficient scale to materially address these issues is an enormous challenge. This paper builds directly on the biophysical study by H.T. Murphy, D.A. O'Connell, R.J. Raison, A.C. Warden, T.H. Booth, A. Herr, A.L. Braid, D.F. Crawford, J.A. Hayward, T. Javonovic, J.G. McIvor, M.H. O'Connor, M.L. Poole, D. Prestwidge, N. Raisbeck‐Brown & L. Rye, In review, which examined a 25 year scale‐up strategy to produce 5% of projected jet fuel demand in Australia in 2020 (470 mL) in the Fitzroy region of Queensland, Australia. The strategy was based on the use of a mixed ligno‐cellulosic biomass feedstock and assumed, for the sake of exploring and quantifying the scenario, a simplified two‐step conversion process – conversion of biomass to crude bio‐oil within the region, and upgrade to jet fuel at a central Brisbane facility. This paper provides details on the costs of production in this scenario, focusing on two different strategies for biomass utilization, and two types of novel small–medium scale conversion technologies. The cost analyses have taken into account technology learning curves, different economies of scale and key cost sensitivities. The cost of biomass‐based jet fuels is estimated to be between 0.70 and 1.90 The airline industry has a strong interest in developing sustainable aviation fuels, in order to reduce their exposure to increasing oil prices and cost liability for greenhouse gas emissions. The feasibility and cost of producing sustainable biomass‐based jet fuels at a sufficient scale to materially address these issues is an enormous challenge. This paper builds directly on the biophysical study by H.T. Murphy, D.A. O'Connell, R.J. Raison, A.C. Warden, T.H. Booth, A. Herr, A.L. Braid, D.F. Crawford, J.A. Hayward, T. Javonovic, J.G. McIvor, M.H. O'Connor, M.L. Poole, D. Prestwidge, N. Raisbeck‐Brown & L. Rye, In review, which examined a 25 year scale‐up strategy to produce 5% of projected jet fuel demand in Australia in 2020 (470 mL) in the Fitzroy region of Queensland, Australia. The strategy was based on the use of a mixed ligno‐cellulosic biomass feedstock and assumed, for the sake of exploring and quantifying the scenario, a simplified two‐step conversion process – conversion of biomass to crude bio‐oil within the region, and upgrade to jet fuel at a central Brisbane facility. This paper provides details on the costs of production in this scenario, focusing on two different strategies for biomass utilization, and two types of novel small–medium scale conversion technologies. The cost analyses have taken into account technology learning curves, different economies of scale and key cost sensitivities. The cost of biomass‐based jet fuels is estimated to be between 0.70 and 1.90 $ L^?1 when the efficiency of conversion of biomass to biocrude and subsequently to aviation fuel is varied by ±10% of published values, with an average value of 1.10 $ L^?1. This is within the range of the projected 2035 conventional jet fuel price of 1.50 $ L^?1. Therefore, biomass‐based jet fuel has the potential to contribute to supply of Australia's jet fuel needs in the future.     

Transparent Cuprous Oxide Photocathode Enabling a Stacked Tandem Cell for Unbiased Water Splitting

Photoelectrochemical water splitting represents an attractive method of capturing and storing the immense energy of sunlight in the form of hydrogen, a clean chemical fuel. Given the large energetic demand of water electrolysis, and the defined spectrum of photons available from incident sunlight, a two absorber tandem device is required to achieve high efficiencies. The two absorbers should be of different and complementary bandgaps, connected in series to achieve the necessary voltage, and arranged in an optical stack configuration to maximize the utilization of sunlight. This latter requirement demands a top device that is responsive to high‐energy photons but also transparent to lower‐energy photons, which pass through to illuminate the bottom absorber. Here, cuprous oxide (Cu₂O) is employed as a top absorber component, and the factors influencing the balance between transparency and efficiency toward operation in a tandem configuration are studied. Photocathodes based on Cu₂O electrodeposited onto conducting glass substrates treated with thin, discontinuous layers of gold achieve reasonable sub‐bandgap transmittance while retaining performances comparable to their opaque counterparts. This new high‐performance transparent photocathode is demonstrated in tandem with a hybrid perovskite photovoltaic cell, resulting in a full device capable of standalone sunlight‐driven water splitting.     

Solar‐to‐Hydrogen Energy Conversion Based on Water Splitting

Artificial photosynthesis provides a blueprint to harvest solar energy to sustain the future energy demands. Solar‐driven water splitting, converting solar energy into hydrogen energy, is the prototype of photosynthesis. Various systems have been designed and evaluated to understand the reaction pathways and/or to meet the requirements of potential applications. In solar‐to‐hydrogen conversion, electrocatalytic hydrogen and oxygen evolution reactions are key research areas that are meaningful both theoretically and practically. To utilize hydrogen energy, fuel cell technology has been extensively investigated because of its high efficiency in releasing chemical energy. In this review, general concepts of the photosynthesis in green plants are discussed, different strategies for the light‐driven water splitting proposed in laboratories are introduced, the progress of electrocatalytic hydrogen and oxygen evolution reactions are reviewed, and finally, the reactions in hydrogen fuel cells are briefly discussed. Overall, the mass and energy circulation in the solar‐hydrogen‐electricity circle are delineated. The authors conclude that attention from scientists and engineers of relevant research areas is still highly needed to eliminate the wide disparity between the aspirations and realities of artificial photosynthesis.     

Carbon–Temperature–Water change analysis for peanut production under climate change: a prototype for the AgMIP Coordinated Climate‐Crop Modeling Project (C3MP)

Climate change is projected to push the limits of cropping systems and has the potential to disrupt the agricultural sector from local to global scales. This article introduces the Coordinated Climate‐Crop Modeling Project (C3MP), an initiative of the Agricultural Model Intercomparison and Improvement Project (AgMIP) to engage a global network of crop modelers to explore the impacts of climate change via an investigation of crop responses to changes in carbon dioxide concentration ([CO₂]), temperature, and water. As a demonstration of the C3MP protocols and enabled analyses, we apply the Decision Support System for Agrotechnology Transfer (DSSAT) CROPGRO‐Peanut crop model for Henry County, Alabama, to evaluate responses to the range of plausible [CO₂], temperature changes, and precipitation changes projected by climate models out to the end of the 21st century. These sensitivity tests are used to derive crop model emulators that estimate changes in mean yield and the coefficient of variation for seasonal yields across a broad range of climate conditions, reproducing mean yields from sensitivity test simulations with deviations of ca. 2% for rain‐fed conditions. We apply these statistical emulators to investigate how peanuts respond to projections from various global climate models, time periods, and emissions scenarios, finding a robust projection of modest (<10%) median yield losses in the middle of the 21st century accelerating to more severe (>20%) losses and larger uncertainty at the end of the century under the more severe representative concentration pathway (RCP8.5). This projection is not substantially altered by the selection of the AgMERRA global gridded climate dataset rather than the local historical observations, differences between the Third and Fifth Coupled Model Intercomparison Project (CMIP3 and CMIP5), or the use of the delta method of climate impacts analysis rather than the C3MP impacts response surface and emulator approach.     

Capacity and Efficiency in Small‐ to Medium‐Sized Biodiesel Production Systems

This article applies principles of industrial ecology to small‐ and medium‐sized biodiesel production facilities. A large potential for gains in efficiency and profit are realized through technology retrofits and the novel application and reuse of process materials. Our basic criteria for sustainability of farm‐scale biodiesel production systems are measured by the following questions: Are all of the resources, mass, and energy flows in the system rational and harmonized? Is the feedstock produced without adverse effects on natural resources or the food chain? We answer these questions by presenting and applying the latest chemical engineering and technology research to support the harmonized and rationalized use of resources and energy within the system boundaries of a farm economy. The feedstock must include refuse and secondary oil sources with low impact on the food chain. Emissions must be reduced to a minimum for a smaller carbon footprint and positive emissions balance from seed to exhaust. Discharges should be avoided; wastes must be turned into primary and intermediary products or energy resources. Proper techniques and routines should serve environmental and human health and safety targets. Reuse of existing assets is considered for improving unit capacity and efficiency, thus lowering costs of conversion. Significant benefits in profitability and production capacity, combined with improved environmental performance, are the main outcomes of the recommended restructuring of production at farm‐scale.     

Desalination and water reuse to address global water scarcity

The act of ensuring freshwater is considered the most essential and basic need for humanity. Although the planet is water-rich in some terms, the freshwater sources available for human consumption and beneficial uses are very limited. Excess population growth, industrial development coupled with improving living standards have caused an unprecedented need for freshwater all over the world. Regions once rich in water resources are struggling to meet the ever increasing demands in recent years. In addition, climate change and unsustainable management practices have led to a situation called “drought” in many regions. Water supplies in drought conditions can be addressed by taking two major approaches related to management and technology development. The management approaches include demand mitigation and supply enhancement. Demand mitigation can be done by implementing water conservation practices, and by enforcing a mechanism to influence user-responsible behavior through higher water fares and other billing routes. Supply enhancement can be achieved by utilizing the methods available for water reclamation, reuse and recycle including rain harvesting. This paper provides a critical insight of the causes for drought and the issues caused by persistent drought conditions followed by discussion of management and technological approaches required to maintain adequate water resources around the world. Challenges and opportunities involved in implementation of desalination and water reuse technologies in addressing global water scarcity are discussed in detail with case studies     

Achieving Dewaterization in Industrial Parks

Water resource management is a critical component of eco‐industrial parks. This article proposes a methodology, termed the water resource management model for industrial parks, that integrates a water input‐output table with water pinch technology. A case study of the Yixing Economic Development Zone (YEDZ) in China illustrates the methodology. Each sector's water utilization and direct and indirect intersectoral interactions of water and water pollutants in 2007 and 2015 are accounted for. It is proposed that water metabolism in 2015 could achieve certain objectives of water resource management in the YEDZ. In addition, future policies are proposed. The YEDZ needs to focus on improving various technologies regarding the manufacture of textiles, the manufacture of raw chemical materials and chemical products, and the production and supply of electric and heat power—which will promote the utilization of water cascading among sectors and encourage the reuse of treated water from wastewater treatment plants. Last, future work for water resource management is proposed.     

Projecting species’ vulnerability to climate change: Which uncertainty sources matter most and extrapolate best?

Species distribution models (SDMs) are commonly used to assess potential climate change impacts on biodiversity, but several critical methodological decisions are often made arbitrarily. We compare variability arising from these decisions to the uncertainty in future climate change itself. We also test whether certain choices offer improved skill for extrapolating to a changed climate and whether internal cross‐validation skill indicates extrapolative skill. We compared projected vulnerability for 29 wetland‐dependent bird species breeding in the climatically dynamic Prairie Pothole Region, USA. For each species we built 1,080 SDMs to represent a unique combination of: future climate, class of climate covariates, collinearity level, and thresholding procedure. We examined the variation in projected vulnerability attributed to each uncertainty source. To assess extrapolation skill under a changed climate, we compared model predictions with observations from historic drought years. Uncertainty in projected vulnerability was substantial, and the largest source was that of future climate change. Large uncertainty was also attributed to climate covariate class with hydrological covariates projecting half the range loss of bioclimatic covariates or other summaries of temperature and precipitation. We found that choices based on performance in cross‐validation improved skill in extrapolation. Qualitative rankings were also highly uncertain. Given uncertainty in projected vulnerability and resulting uncertainty in rankings used for conservation prioritization, a number of considerations appear critical for using bioclimatic SDMs to inform climate change mitigation strategies. Our results emphasize explicitly selecting climate summaries that most closely represent processes likely to underlie ecological response to climate change. For example, hydrological covariates projected substantially reduced vulnerability, highlighting the importance of considering whether water availability may be a more proximal driver than precipitation. However, because cross‐validation results were correlated with extrapolation results, the use of cross‐validation performance metrics to guide modeling choices where knowledge is limited was supported.     

广东省水资源特点和合理开发利用研究

本文论述广东水资源量,时空分布和季节变化特点,并分析广东用水存在问题,不合理开发利用水资源和浪费水;水库蓄水和调节能力未能满足用水要求;水质污染日渐严重。使水资源渐感紧缺。按目前用水趋势,要达到供需水平衡,必须成立统一管理水资源的流域机构;按不同的经济发展阶段,改变其主要洪水职能;节约用水;增加水库的供水和调节能力;改变调峰发电方式：提高重复用水率;保护水质;做好水土保持工作。最后提出,制定地方经济发展总体规划时,其用水量必须与可能供水量相适应。     

Phytoremediation of Parboiled Rice Mill Wastewater Using Water Lettuce (Pistia Stratiotes)

Phytoremediation is an emerging technology applied for treatment of wastewater. It is a suitable option notably in developing countries as it is simple, sustainable and cost effective. In the present lab-based batch study the free floating aquatic plant water lettuce (Pistia stratiotes) is used for treatment of parboiled rice mill wastewater having low pH, high chemical oxygen demand (COD), nitrogen, and phosphate. In raw rice mill wastewater (undiluted) growth of water lettuce is found to be inhibited. Later on, two different dilution approaches (raw and facultative pond effluent 1:1; raw and tap water 1:1) are applied in order to effectively use this technology. In all cases a control (without plant) is maintained to compare the performance with the Aquatic Plant based Treatment (APT) system. In the APT system results reveal that removal of soluble COD (SCOD), ammoniacal nitrogen (NH₄-N), nitrate nitrogen (NO₃-N), and soluble phosphorus (sol. P) are upto 65%, 98%, 70%, and 65% respectively. The study highlights the efficacy of water lettuce in removing organics and nutrients from parboiled rice mill wastewater.