The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,...The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,the influence of CO_(2) concentration and temperature fluctuations on adsorbent performance remains a key research focus.Among various waste materials,waste clay bricks are particularly suitable for Li_(4)SiO_(4) synthesis due to their high SiO_(2) content(60% to 70%),while enabling waste valorization.Furthermore,it has been demonstrated that heteroatoms present in the waste materials positively in-fluence the CO_(2) adsorption performance of Li_(4)SiO_(4)-based adsorbents.In this study,Li_(4)SiO_(4) was syn thesized for the first time directly from waste clay bricks without pretreatment.Comprehensive characterization revealed that the resulting Li_(4)SiO_(4)-based adsorbent exhibits outstanding performance:a high CO_(2) capture capacity(27.9%(mass)),excellent cycling stability,and remarkable thermal energy storage capability(876.4 kJ·kg^(-1)).These superior properties position it as one of the most promising high-temperature adsorbents for simultaneous CO_(2) capture and thermal energy storage(TES)from fossil fuel flue gase.Moreover,the adsorbent maintained excellent stability under fluctuating temper-ature and CO_(2) concentration.Even at 20%(vol)CO_(2) and 500℃,it achieved a high capacity of 25.7%(mass),reaching equilibrium within 15 min.This CO_(2) capture performance is truly impressive.展开更多
The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environment...The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environmentally friendly and economical method of P recovery from municipal wastewater,providing the P source for LiFePO_(4) cathodes.The novel approach utilizes the sludge of Fe-coagulant-based chemical P removal(CPR)in wastewater treatment.After a sintering treatment with acid washing,the CPR sludge,enriched with P and Fe,transforms into purified P-Fe oxides(Fe2.1P1.0O5.6).These oxides can substitute up to 35%of the FePO_(4) reagent as precursor,producing a carbon-coated LiFePO_(4)(LiFePO_(4)/C)cathode with a specific discharge capacity of 114.9 mA·h·g^(-1)at current density of 17 mA·g^(-1)),and cycle stability of 99.2%after 100 cycles.The enhanced cycle performance of the as-prepared LiFePO_(4)/C cathode may be attributed to the incorporations of impurities(such as Ca^(2+)and Na^(+))from sludge,with improved stability of crystal structure.Unlike conventional P-fertilizers,this P recovery technology converts 100%of P in CPR sludge into the production of value-added LiFePO_(4)/C cathodes.The recovered P from municipal wastewater can meet up to 35%of the P demand in the Chinese LIBs industry,offering a cost-effective solution for addressing the pressing challenges of P scarcity.展开更多
Secondary aluminum dross(SAD)is a rich source of recyclable aluminum but poses considerable risk due to its high AlN con-tent.Therefore,thoroughly removing AlN is essential,but intricate aluminum components and expens...Secondary aluminum dross(SAD)is a rich source of recyclable aluminum but poses considerable risk due to its high AlN con-tent.Therefore,thoroughly removing AlN is essential,but intricate aluminum components and expensive additives pose challenges to the process.In this study,waste sodium acetate is proposed as an environmentally friendly additive for completely removing AlN and enhancing the extraction of aluminum from SAD.Through the exothermic decomposition of NaAc,reactions can occur at 850℃.AlN removal efficiency reached 93.19%after sintering,whereas Al leaching efficiency in the subsequent leaching process reached 90.49%,which were 37.86%and 375.26%higher than the removal efficiency of the control,respectively.These favorable results were attributed to the comprehensive transformation of aluminum species.The formation of soluble phase Na_(1.95)Al_(1.95)Si_(0.05)O_(4) occurred during the destruction of the Al_(2)O_(3) layer surrounding AlN and the transformation of other aluminum components.AlN decomposed upon contact with NaAc.There-fore,this study utilizes the decomposition properties of NaAc to provide an efficient and environmentally friendly route for removing AlN and extracting Al from SAD.展开更多
Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated...Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.展开更多
Antibiotic-contaminated wastewater poses a global threat to aquatic ecosystems.Fenton-like oxidative processes effectively decompose recalcitrant pollutants.While these oxidative processes effectively break down targe...Antibiotic-contaminated wastewater poses a global threat to aquatic ecosystems.Fenton-like oxidative processes effectively decompose recalcitrant pollutants.While these oxidative processes effectively break down target contaminants,they may also produce uncontrolled intermediates,potentially resulting in unexpected combined toxicities.This review explores the chemical mechanisms behind Fenton-like reactions,particularly in antibiotic removal,and evaluates the formation of byproducts and their potential toxicological effects.Furthermore,recommendations for optimizing catalyst design and treatment conditions are provided to enhance degradation performance while minimizing ecological risks.This study highlights critical concerns regarding the toxicity of degradation byproducts and their impact on ecosystems by integrating chemical and biological risk assessments.By integrating chemical and biological risk assessments with computational toxicology,particularly quantitative structure-activity relationship(QSAR)modeling,this study proposes a comprehensive approach to evaluate degradation and toxicity.This work highlights the importance of a comprehensive framework for evaluating degradation efficiency and toxicity,contributing to safer and more effective antibiotic wastewater treatment strategies.The findings underscore the importance of balancing degradation efficiency with environmental safety in wastewater treatment processes involving advanced oxidative technologies.展开更多
Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air in...Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air injection with dual atomizing nozzles,for the thermal treatment of waste piles.Numerical simulations are employed to investigate the influence of various parameters,namely,nozzle height,nozzle tilt angle,inlet air velocity and air temperature,on the droplet diffusion process,spread area,droplet temperature,and droplet size distribution.The results show that reducing the nozzle height increases the temperature of droplets upon their deposition on the waste pile.Specifically,when the nozzle height is lowered to 1.5 m,the temperature of the droplets reaching the waste pile is 1℃higher than when the nozzle height is set at 2 m.Furthermore,an increase in the nozzle tilt angle expands the overlapping heating area.For instance,when the nozzle angle is increased from 15°to 30°,the overlapping spread area expands by 3.21 m2.Additionally,increasing the inlet air velocity enhances the droplet diffusion range.At an air velocity of 2 m/s,the droplet diffusion range grows to 14.4 m,representing a 6.7%increase compared to the nowind condition.While the average droplet diameter decreases to 1.53 mm,the droplet temperature decreases by 1℃.Moreover,the droplet temperature is found to become smaller as the ambient temperature inside the waste warehouse declines.Specifically,a 5℃reduction in the ambient temperature results in a 1℃decrease in the average temperature of the atomized droplets.The study concludes that a nozzle height of 1.5 m and a nozzle tilt angle of 30°effectively meet practical heating requirements.展开更多
The increasing need for sustainable energy and the environmental impacts of reliance on fossil fuels have sparked greater interest in biomass as a renewable energy source.This review provides an in-depth assessment of...The increasing need for sustainable energy and the environmental impacts of reliance on fossil fuels have sparked greater interest in biomass as a renewable energy source.This review provides an in-depth assessment of biooil and biochar generation through the pyrolysis of sawdust,a significant variety of lignocellulosic biomass.The paper investigates different thermochemical conversion methods,including fast,slow,catalytic,flash,and co-pyrolysis,while emphasizing their operational parameters,reactor designs,and effects on product yields.The influence of temperature,heating rate,and catalysts on enhancing the quality and quantity of bio-oil and biochar is thoroughly analyzed.Additionally,the review examines advanced reactor technologies such as fluidized beds,fixed beds,auger reactors,and plasma pyrolysis systems.It also discusses recent progress in catalyst innovation and product enhancement techniques to overcome the challenges posed by bio-oil,including its high oxygen content and low stability.By synthesizing experimental results and conducting comparative analyses,the paper identifies existing research gaps and provides insights into future paths for effective biomass utilization,thereby aiding in the creation of economically viable and environmentally responsible bioenergy systems.展开更多
Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals.Chain elongation(CE)for production of mediumchain carboxylic acids(MCCAs,especially c...Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals.Chain elongation(CE)for production of mediumchain carboxylic acids(MCCAs,especially caproate,enanthate and caprylate)from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society.The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production.Additionally,the microbial characteristics of the CE process are surveyed and discussed.Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed,we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission.This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste,or even non-biodegradable waste(such as,plastics and rubbers).Meanwhile,the remaining scientific questions,unsolved problems,application potential and possible developments for this technology are discussed.展开更多
Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment （MBT） makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT...Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment （MBT） makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT and also enhance resource recovery of the organic and inorganic fraction. The MBT plant at Gescher, Germany, is used as an example in order to determine the quantity and composition of process water and leachates from intensive and subsequent rotting, pressing water from anaerobic digestion and scrubber water from acid exhaust air treatment, and hence prepare an MBT water balance. The potential of, requirements for and limits to internal process water reuse as well as the possibilities of resource recovery from scrubber water are also examined. Finally, an assimilated process water management concept with the purpose of an extensive reduction of wastewater quantity and freshwater demand is presented.展开更多
In order to investigate the anti-leaching capability of pyrochlore Gd2Zr2O7 immobilized An3＋, trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd2-xNdxZr2O7（0.0 ≤ x≤2.0） ser...In order to investigate the anti-leaching capability of pyrochlore Gd2Zr2O7 immobilized An3＋, trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd2-xNdxZr2O7（0.0 ≤ x≤2.0） series samples were successfully synthesized by high temperature solid reaction and using Gd2O3, ZrO2 powders as starting materials. The experiments of long-term chemical stability were conducted in synthetic seawater at 40 and 70 ℃. The XRD diffractive data and extraction ratio of as-received samples were collected with the help of X-ray diffraction （XRD） instrument and inductively coupled plasma mass spectrometry （ICP- Mass）. The results indicate that the phases of as-received compounds keep the single phase of pyrochlore. The extraction ratio of Gd3＋, Zr4＋ and Nd3＋ in waste forms is increasing with the increase of immersion time in synthetic seawater. The extraction ratio of waste forms at 70 ℃ is higher than at 40 ℃. The highest extraction ratio of Gd3＋, Zr4＋ and Nd3＋ after 42 days is near 0.025 8, 0.003 8 and 0.045 2 μg.mL-1, respectively.展开更多
With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is inte...With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.展开更多
Is our food safe and free of the crisis of antibiotics and antibiotic resistance (AR)?And will the derived food waste (FW) impose AR risk to the environment after biological treatment? This study used restaurant FW le...Is our food safe and free of the crisis of antibiotics and antibiotic resistance (AR)?And will the derived food waste (FW) impose AR risk to the environment after biological treatment? This study used restaurant FW leachates flowing through a 200 tons-waste/day biological treatment plant as a window to investigate the fate of antibiotics and antibiotic-resistance genes (ARGs) during the acceptance and treatment of FW.Sulfonamides (sulfamethazine,sulfamethoxazole) and quinolones (ciprofloxacin,enrofloxacin,ofloxacin) were detected during FW treatment,while tetracyclines,macrolides and chloramphenicols were not observable.ARGs encoding resistance to sulfonamides,tetracyclines and macrolides emerged in FW leachates.Material flow analysis illustrated that the total amount of antibiotics (except sulfamethazine) and ARGs were constant during FW treatment processes.Both the concentration and total amount of most antibiotics and ARGs fluctuated during treatment,physical processes (screening,centrifugation,solid-liquid and oil-water separation) did not decrease antibiotic or ARGs concentrations or total levels permanently;the affiliated wastewater treatment plant appeared to remove sulfonamides and most ARGs concentrations and total amount.Heavy metals Ni,Co and Cu were important for disseminating antibiotics concentrations and MGEs for distributing ARGs concentrations.Humic substances (fulvic acids,hydrophilic fractions),C-associated and N-associated contents were essential for the distribution of the total amounts of antibiotics and ARGs.Overall,this study implied that human food might not be free of antibiotics and ARGs,and FW was an underestimated AR pool with various determinants.Nonetheless,derived hazards of FW could be mitigated through biological treatment with well-planned daily operations.展开更多
HCl and SO_2 emission is one of the major concerns related to municipal solid waste incinerator(MSWI). In this study, a material flow analysis model was developed to estimate the HCl and SO_2 concentrations in the MSW...HCl and SO_2 emission is one of the major concerns related to municipal solid waste incinerator(MSWI). In this study, a material flow analysis model was developed to estimate the HCl and SO_2 concentrations in the MSWI flue gases(FGs), and their concentrations in the full-scale MSWI were monitored. The calculated concentrations of HCl and SO_2 in the FG were 770–1300 mg/Nm^3 and 150–640 mg/Nm^3, respectively, in close agreement with the monitored values. More than 99% of Cl and 92% of S from the FG were captured into solid residues by the air pollution control(APC) systems. Moreover, since only 48.4%–67.5% of Cl and 21.3%–53.4% of S were transferred to the FG from the municipal solid waste(MSW), it was more reliable to estimate the source strengths and release amounts of HCl and SO_2 in the FG based on the amounts of Cl and S in the APC residues(AR) and exhaust gas rather than in the MSW. This simple method is easily applicable and the estimated results could provide scientific basis for the appropriate design and operation of the APC systems as well as corrosion control of heat recovery systems.展开更多
Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation ...Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation is considered as a principal barrier on which the fulfillment of key safety functions rests. Between 2006 and 2010, the European Commission project TIMODAZ, which gathered 15 partners from 8 countries, has investigated the coupled thermo-hydro-mechanical （THM） effects on clay formations for geological disposal of radioactive waste, and specific attention was paid to investigating the thermal effect on the evolution of the damaged zone （DZ）. Three types of potential host clay formations were investigated： the Boom Clay （Belgium）, the Opalinus Clay （Switzerland） and the Callovo-Oxfordian argillite （France）. Intensive experimental （laboratory and in situ in underground research laboratories） and numerical studies have been performed. Multi-scale approach was used in the course of the project. High degree of similarities between the failure modes, sealing process, stress paths, deformation, etc., observed in laboratories and in situ has been obtained, which increased the confidence in the applicability of laboratory test results and up-scaling perspective. The results of the laboratory and in situ tests obtained allowed the parameters for numerical models at various scales to be derived and provided the basis for the simplified performance assessment models that are used to assess the long-term safety of a repository. The good cooperation between the numerical modeler and experimenters has allowed an in-depth analysis of the experimental results and thus better understanding the underlying processes, and consequently increased the capabilities to model the THM effects in claystones. This paper presents the main achievements obtained by TIMODAZ project and shows how a European scientific community investigates a problem of concern in a collaborative way and how the obtained main results are applied to the performance assessment of a geological repository.展开更多
Municipal solid waste(MSW) incineration has become an important anthropogenic source of heavy metals(HMs) to the environment. However, assessing the impact of MSW incineration on HMs in the environment, especially soi...Municipal solid waste(MSW) incineration has become an important anthropogenic source of heavy metals(HMs) to the environment. However, assessing the impact of MSW incineration on HMs in the environment, especially soils, can be a challenging task because of various HM sources. To investigate the effect of MSW incineration on HMs in soils, soil samples collected at different distances from four MSW incinerators in Shanghai, China were analyzed for their contents of eight HMs(antimony, cadmium, chromium, copper,lead, mercury, nickel, and zinc) and lead(Pb) isotope ratios. Source identification and apportionment of HMs were accomplished using principal component analysis and Pb isotope analysis. Results indicated that the relatively high contents of cadmium, lead,antimony, and zinc in the soils at 250 m and 750–1250 m away from the MSW incinerators were related to MSW incineration, while the elevated contents of the other four HMs were associated with other anthropogenic activities. Based on Pb isotope analysis, the contribution ratio of MSW incineration(which had been operated for more than 14 years)to the accumulation of Pb in soil was approximately 10% on average, which was lower than coal combustion only. Incinerator emissions of Pb could have a measurable effect on the soil contamination within a limited area(≤1500 m).展开更多
The influence of temperature on the performance of anaerobic reactors for treating the organic fraction of municipal sohd waste （OFMSW） was studied. Batch digestion of OFMSW was carded out for 32 d at different temp...The influence of temperature on the performance of anaerobic reactors for treating the organic fraction of municipal sohd waste （OFMSW） was studied. Batch digestion of OFMSW was carded out for 32 d at different temperature （25℃, 35℃, 45℃ and 55℃） conditions for total solid concentrations （TS） 17% with the ratio of total organic carbon to nitrogen （C/N） being, 25：1 respectively, while keeping other parameters constant such as inoculum, start-up pH, reactor volume （2 L） and so on. Temperature can influence the methanogenic bacteria activity, accordingly inhibiting the OFMSW biodegradation and stabilization efficiency. Anaerobic reactors excelled at TS reduction, total volatile solid reduction, chemical oxygen demand reduction, increasing cumulative biogas production, whose rate was at temperature （35℃ and 55℃） conditions. Methane concentration in the biogas was above 65% in four reactors. In addition, the fluctuation of temperatures resulted in the biogas production variation. The data obtained indicated that temperature had a significant influence on anaerobic process.展开更多
Transfer station(TS)is an integral part of present-day municipal solid waste(MSW)management systems.To provide information for the incorporation of waste facilities within the current integrated waste management syste...Transfer station(TS)is an integral part of present-day municipal solid waste(MSW)management systems.To provide information for the incorporation of waste facilities within the current integrated waste management system,the authors measured the existing environmental quality at five MSW TSs.Discharged wastewater,air,and noise were monitored and assayed at the five TSs in Beijing in 2001-2006 during rainy seasons(RSs)and dry seasons(DSs).Except Ammonia(NH_3)and hydrogen sulfide(H_2S),the analytical results of...展开更多
The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator （MSWI） fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different c...The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator （MSWI） fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas. The reaction between fly ash and 100% CO2 was relatively fast; the uptake of CO2 reached 87 g CO2/kg ash, and the sequestered CO2 could be entirely released at high temperatures. When CO2 content was reduced to 12%, the reaction rate decreased; the uptake fell to 41 g CO2/kg ash, and 70.7% of the sequestered CO2 could be released. With 12% CO2 in the presence of SO2, the reaction rate significantly decreased; the uptake was just 17 g CO2/kg ash, and only 52.9% of the sequestered CO2 could be released. SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.展开更多
The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an M...The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(～2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.展开更多
In Belgium,the Boom clay was selected as a potential host formation for the disposal of high-level radioactive waste（HLW）.To demonstrate the suitability of Boom clay for bearing thermal load induced by the HLW,a lar...In Belgium,the Boom clay was selected as a potential host formation for the disposal of high-level radioactive waste（HLW）.To demonstrate the suitability of Boom clay for bearing thermal load induced by the HLW,a large-scale in-situ heater test,called PRACLAY heater test,will be conducted in the underground research laboratory（URL） in Mol.Owing to the limitations of the test（a short period of time compared with that considered in a real repository,different boundary conditions,etc.）,the test is designed to simulate,in a conservative way,the most critical state and phenomena that could occur in the host rock.The PRACLAY gallery was excavated at the end of 2007;the heating phase will begin in 2010 and will last for at least 10 years.The PRACLAY gallery itself leaves an opportunity to study the possibilities of sealing a disposal drift in Boom clay and testing the feasibility of hydraulic cut-off of any preferential pathway to the main access gallery through the excavation damage zone（EDZ） and the lining with a seal in a horizontal drift（horizontal seal）.Indeed,this is a generic problem for all deep geological disposal facilities for HLW.An annular seal made of compacted swelling bentonite will be installed in the front of the heated part of the PRACLAY gallery for these purposes.This paper provides detailed considerations on the thermo-hydro-mechanical（THM） boundary conditions for the design of the PRACLAY heater test and the seal test with the support of numerical calculations.It is believed that these important items considered in the PRACLAY heater test design also constitute key issues for the repository design.The outcome of the PRACLAY heater test will be an important milestone for the Belgian repository design.展开更多
基金the National Natural Science Foundation of China(5240101142)Yunnan Province basic research project(202401CF070252)+1 种基金the Key R&D plan of Yunnan Province(202303AC100008)the Scientific Researching Fund Projects of Yunnan Provincial Department of Education(2025J0077),which funded this study。
文摘The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,the influence of CO_(2) concentration and temperature fluctuations on adsorbent performance remains a key research focus.Among various waste materials,waste clay bricks are particularly suitable for Li_(4)SiO_(4) synthesis due to their high SiO_(2) content(60% to 70%),while enabling waste valorization.Furthermore,it has been demonstrated that heteroatoms present in the waste materials positively in-fluence the CO_(2) adsorption performance of Li_(4)SiO_(4)-based adsorbents.In this study,Li_(4)SiO_(4) was syn thesized for the first time directly from waste clay bricks without pretreatment.Comprehensive characterization revealed that the resulting Li_(4)SiO_(4)-based adsorbent exhibits outstanding performance:a high CO_(2) capture capacity(27.9%(mass)),excellent cycling stability,and remarkable thermal energy storage capability(876.4 kJ·kg^(-1)).These superior properties position it as one of the most promising high-temperature adsorbents for simultaneous CO_(2) capture and thermal energy storage(TES)from fossil fuel flue gase.Moreover,the adsorbent maintained excellent stability under fluctuating temper-ature and CO_(2) concentration.Even at 20%(vol)CO_(2) and 500℃,it achieved a high capacity of 25.7%(mass),reaching equilibrium within 15 min.This CO_(2) capture performance is truly impressive.
基金supported by the National Natural Science Foundation of China(52100093,52270128,and 52261135627)the Guangdong Basic and Applied Basic Research Foundation(2023A1515011734 and 2021B1515120068)+2 种基金the Municipal Science and Technology Innovation Council of the Shen-zhen Government(KCXFZ20211020163556020 and SGDX20230116092359002)the Research Grants Council(17210219)the Innovation and Technology Fund(ITS/242/20FP)of the Hong Kong SAR Government。
文摘The rapidly growing demand for lithium iron phosphate(LiFePO_(4))as the cathode material of lithium-ion batteries(LIBs)has aggravated the scarcity of phosphorus(P)reserves on Earth.This study introduces an environmentally friendly and economical method of P recovery from municipal wastewater,providing the P source for LiFePO_(4) cathodes.The novel approach utilizes the sludge of Fe-coagulant-based chemical P removal(CPR)in wastewater treatment.After a sintering treatment with acid washing,the CPR sludge,enriched with P and Fe,transforms into purified P-Fe oxides(Fe2.1P1.0O5.6).These oxides can substitute up to 35%of the FePO_(4) reagent as precursor,producing a carbon-coated LiFePO_(4)(LiFePO_(4)/C)cathode with a specific discharge capacity of 114.9 mA·h·g^(-1)at current density of 17 mA·g^(-1)),and cycle stability of 99.2%after 100 cycles.The enhanced cycle performance of the as-prepared LiFePO_(4)/C cathode may be attributed to the incorporations of impurities(such as Ca^(2+)and Na^(+))from sludge,with improved stability of crystal structure.Unlike conventional P-fertilizers,this P recovery technology converts 100%of P in CPR sludge into the production of value-added LiFePO_(4)/C cathodes.The recovered P from municipal wastewater can meet up to 35%of the P demand in the Chinese LIBs industry,offering a cost-effective solution for addressing the pressing challenges of P scarcity.
基金supported by the National Natural Science Foundation of China(No.22276062)the Guangdong Science and Technology Program,China(No.2020B121201003).
文摘Secondary aluminum dross(SAD)is a rich source of recyclable aluminum but poses considerable risk due to its high AlN con-tent.Therefore,thoroughly removing AlN is essential,but intricate aluminum components and expensive additives pose challenges to the process.In this study,waste sodium acetate is proposed as an environmentally friendly additive for completely removing AlN and enhancing the extraction of aluminum from SAD.Through the exothermic decomposition of NaAc,reactions can occur at 850℃.AlN removal efficiency reached 93.19%after sintering,whereas Al leaching efficiency in the subsequent leaching process reached 90.49%,which were 37.86%and 375.26%higher than the removal efficiency of the control,respectively.These favorable results were attributed to the comprehensive transformation of aluminum species.The formation of soluble phase Na_(1.95)Al_(1.95)Si_(0.05)O_(4) occurred during the destruction of the Al_(2)O_(3) layer surrounding AlN and the transformation of other aluminum components.AlN decomposed upon contact with NaAc.There-fore,this study utilizes the decomposition properties of NaAc to provide an efficient and environmentally friendly route for removing AlN and extracting Al from SAD.
基金the National Natural Science Foundation of China(Grant Nos.42177163 and 42071080)the China Postdoctoral Science Foundation(Grant No.2022M723347).
文摘Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.
基金supported by the National Natural Science Foundation of China(No.52370168)the Key Laboratory of Functional Biology and Pollution Control in red soil regions of Jiangxi Province(No.2023SSY02051)。
文摘Antibiotic-contaminated wastewater poses a global threat to aquatic ecosystems.Fenton-like oxidative processes effectively decompose recalcitrant pollutants.While these oxidative processes effectively break down target contaminants,they may also produce uncontrolled intermediates,potentially resulting in unexpected combined toxicities.This review explores the chemical mechanisms behind Fenton-like reactions,particularly in antibiotic removal,and evaluates the formation of byproducts and their potential toxicological effects.Furthermore,recommendations for optimizing catalyst design and treatment conditions are provided to enhance degradation performance while minimizing ecological risks.This study highlights critical concerns regarding the toxicity of degradation byproducts and their impact on ecosystems by integrating chemical and biological risk assessments.By integrating chemical and biological risk assessments with computational toxicology,particularly quantitative structure-activity relationship(QSAR)modeling,this study proposes a comprehensive approach to evaluate degradation and toxicity.This work highlights the importance of a comprehensive framework for evaluating degradation efficiency and toxicity,contributing to safer and more effective antibiotic wastewater treatment strategies.The findings underscore the importance of balancing degradation efficiency with environmental safety in wastewater treatment processes involving advanced oxidative technologies.
文摘Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air injection with dual atomizing nozzles,for the thermal treatment of waste piles.Numerical simulations are employed to investigate the influence of various parameters,namely,nozzle height,nozzle tilt angle,inlet air velocity and air temperature,on the droplet diffusion process,spread area,droplet temperature,and droplet size distribution.The results show that reducing the nozzle height increases the temperature of droplets upon their deposition on the waste pile.Specifically,when the nozzle height is lowered to 1.5 m,the temperature of the droplets reaching the waste pile is 1℃higher than when the nozzle height is set at 2 m.Furthermore,an increase in the nozzle tilt angle expands the overlapping heating area.For instance,when the nozzle angle is increased from 15°to 30°,the overlapping spread area expands by 3.21 m2.Additionally,increasing the inlet air velocity enhances the droplet diffusion range.At an air velocity of 2 m/s,the droplet diffusion range grows to 14.4 m,representing a 6.7%increase compared to the nowind condition.While the average droplet diameter decreases to 1.53 mm,the droplet temperature decreases by 1℃.Moreover,the droplet temperature is found to become smaller as the ambient temperature inside the waste warehouse declines.Specifically,a 5℃reduction in the ambient temperature results in a 1℃decrease in the average temperature of the atomized droplets.The study concludes that a nozzle height of 1.5 m and a nozzle tilt angle of 30°effectively meet practical heating requirements.
文摘The increasing need for sustainable energy and the environmental impacts of reliance on fossil fuels have sparked greater interest in biomass as a renewable energy source.This review provides an in-depth assessment of biooil and biochar generation through the pyrolysis of sawdust,a significant variety of lignocellulosic biomass.The paper investigates different thermochemical conversion methods,including fast,slow,catalytic,flash,and co-pyrolysis,while emphasizing their operational parameters,reactor designs,and effects on product yields.The influence of temperature,heating rate,and catalysts on enhancing the quality and quantity of bio-oil and biochar is thoroughly analyzed.Additionally,the review examines advanced reactor technologies such as fluidized beds,fixed beds,auger reactors,and plasma pyrolysis systems.It also discusses recent progress in catalyst innovation and product enhancement techniques to overcome the challenges posed by bio-oil,including its high oxygen content and low stability.By synthesizing experimental results and conducting comparative analyses,the paper identifies existing research gaps and provides insights into future paths for effective biomass utilization,thereby aiding in the creation of economically viable and environmentally responsible bioenergy systems.
基金supported by the National Natural Science Foundation of China (Nos. 51622809, 51878471)
文摘Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals.Chain elongation(CE)for production of mediumchain carboxylic acids(MCCAs,especially caproate,enanthate and caprylate)from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society.The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production.Additionally,the microbial characteristics of the CE process are surveyed and discussed.Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed,we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission.This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste,or even non-biodegradable waste(such as,plastics and rubbers).Meanwhile,the remaining scientific questions,unsolved problems,application potential and possible developments for this technology are discussed.
文摘Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment （MBT） makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT and also enhance resource recovery of the organic and inorganic fraction. The MBT plant at Gescher, Germany, is used as an example in order to determine the quantity and composition of process water and leachates from intensive and subsequent rotting, pressing water from anaerobic digestion and scrubber water from acid exhaust air treatment, and hence prepare an MBT water balance. The potential of, requirements for and limits to internal process water reuse as well as the possibilities of resource recovery from scrubber water are also examined. Finally, an assimilated process water management concept with the purpose of an extensive reduction of wastewater quantity and freshwater demand is presented.
基金Funded Partly by the Key Project of National High Technology Research and Development Program(863 Program)(No.2009AA050703)the National Natural Science Youth Foundation of China(Nos.41302028,21007052)+1 种基金the Sichuan Province Science and Technology Support Program(No.2011GZ0252)the Joint Laboratory for Extreme Conditions Matter Properties,Southwest University Science and Technology and Research Center of Laser Fusion,China Academy of Engineering Physics(No.12zxjk04)
文摘In order to investigate the anti-leaching capability of pyrochlore Gd2Zr2O7 immobilized An3＋, trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd2-xNdxZr2O7（0.0 ≤ x≤2.0） series samples were successfully synthesized by high temperature solid reaction and using Gd2O3, ZrO2 powders as starting materials. The experiments of long-term chemical stability were conducted in synthetic seawater at 40 and 70 ℃. The XRD diffractive data and extraction ratio of as-received samples were collected with the help of X-ray diffraction （XRD） instrument and inductively coupled plasma mass spectrometry （ICP- Mass）. The results indicate that the phases of as-received compounds keep the single phase of pyrochlore. The extraction ratio of Gd3＋, Zr4＋ and Nd3＋ in waste forms is increasing with the increase of immersion time in synthetic seawater. The extraction ratio of waste forms at 70 ℃ is higher than at 40 ℃. The highest extraction ratio of Gd3＋, Zr4＋ and Nd3＋ after 42 days is near 0.025 8, 0.003 8 and 0.045 2 μg.mL-1, respectively.
基金support from the China Atomic Energy Authority (CAEA) for China's URL Development Program and the Geological Disposal ProgramThe International Atomic Energy Agency is specially thanked for its support for China's geological disposal program through its Technical Cooperation Projects
文摘With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.
基金supported by the National Natural Science Foundation of China(No.51622809)
文摘Is our food safe and free of the crisis of antibiotics and antibiotic resistance (AR)?And will the derived food waste (FW) impose AR risk to the environment after biological treatment? This study used restaurant FW leachates flowing through a 200 tons-waste/day biological treatment plant as a window to investigate the fate of antibiotics and antibiotic-resistance genes (ARGs) during the acceptance and treatment of FW.Sulfonamides (sulfamethazine,sulfamethoxazole) and quinolones (ciprofloxacin,enrofloxacin,ofloxacin) were detected during FW treatment,while tetracyclines,macrolides and chloramphenicols were not observable.ARGs encoding resistance to sulfonamides,tetracyclines and macrolides emerged in FW leachates.Material flow analysis illustrated that the total amount of antibiotics (except sulfamethazine) and ARGs were constant during FW treatment processes.Both the concentration and total amount of most antibiotics and ARGs fluctuated during treatment,physical processes (screening,centrifugation,solid-liquid and oil-water separation) did not decrease antibiotic or ARGs concentrations or total levels permanently;the affiliated wastewater treatment plant appeared to remove sulfonamides and most ARGs concentrations and total amount.Heavy metals Ni,Co and Cu were important for disseminating antibiotics concentrations and MGEs for distributing ARGs concentrations.Humic substances (fulvic acids,hydrophilic fractions),C-associated and N-associated contents were essential for the distribution of the total amounts of antibiotics and ARGs.Overall,this study implied that human food might not be free of antibiotics and ARGs,and FW was an underestimated AR pool with various determinants.Nonetheless,derived hazards of FW could be mitigated through biological treatment with well-planned daily operations.
基金supported by the National Natural Science Foundation of China (No.21577102)the Major Science and Technology Program for Water Pollution Control and Treatment (No.2017ZX07202005)the Fundamental Research Funds for the Central Universities (No.22120170050)
文摘HCl and SO_2 emission is one of the major concerns related to municipal solid waste incinerator(MSWI). In this study, a material flow analysis model was developed to estimate the HCl and SO_2 concentrations in the MSWI flue gases(FGs), and their concentrations in the full-scale MSWI were monitored. The calculated concentrations of HCl and SO_2 in the FG were 770–1300 mg/Nm^3 and 150–640 mg/Nm^3, respectively, in close agreement with the monitored values. More than 99% of Cl and 92% of S from the FG were captured into solid residues by the air pollution control(APC) systems. Moreover, since only 48.4%–67.5% of Cl and 21.3%–53.4% of S were transferred to the FG from the municipal solid waste(MSW), it was more reliable to estimate the source strengths and release amounts of HCl and SO_2 in the FG based on the amounts of Cl and S in the APC residues(AR) and exhaust gas rather than in the MSW. This simple method is easily applicable and the estimated results could provide scientific basis for the appropriate design and operation of the APC systems as well as corrosion control of heat recovery systems.
基金funded by the European Commission through the TIMODAZ project within the 6th framework programme (Contract Number: FI6W-CT-2007-036449)
文摘Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation is considered as a principal barrier on which the fulfillment of key safety functions rests. Between 2006 and 2010, the European Commission project TIMODAZ, which gathered 15 partners from 8 countries, has investigated the coupled thermo-hydro-mechanical （THM） effects on clay formations for geological disposal of radioactive waste, and specific attention was paid to investigating the thermal effect on the evolution of the damaged zone （DZ）. Three types of potential host clay formations were investigated： the Boom Clay （Belgium）, the Opalinus Clay （Switzerland） and the Callovo-Oxfordian argillite （France）. Intensive experimental （laboratory and in situ in underground research laboratories） and numerical studies have been performed. Multi-scale approach was used in the course of the project. High degree of similarities between the failure modes, sealing process, stress paths, deformation, etc., observed in laboratories and in situ has been obtained, which increased the confidence in the applicability of laboratory test results and up-scaling perspective. The results of the laboratory and in situ tests obtained allowed the parameters for numerical models at various scales to be derived and provided the basis for the simplified performance assessment models that are used to assess the long-term safety of a repository. The good cooperation between the numerical modeler and experimenters has allowed an in-depth analysis of the experimental results and thus better understanding the underlying processes, and consequently increased the capabilities to model the THM effects in claystones. This paper presents the main achievements obtained by TIMODAZ project and shows how a European scientific community investigates a problem of concern in a collaborative way and how the obtained main results are applied to the performance assessment of a geological repository.
基金supported by the National Natural Science Foundation of China(Nos.21577102,21277096)the Fundamental Research Funds for the Central Universities
文摘Municipal solid waste(MSW) incineration has become an important anthropogenic source of heavy metals(HMs) to the environment. However, assessing the impact of MSW incineration on HMs in the environment, especially soils, can be a challenging task because of various HM sources. To investigate the effect of MSW incineration on HMs in soils, soil samples collected at different distances from four MSW incinerators in Shanghai, China were analyzed for their contents of eight HMs(antimony, cadmium, chromium, copper,lead, mercury, nickel, and zinc) and lead(Pb) isotope ratios. Source identification and apportionment of HMs were accomplished using principal component analysis and Pb isotope analysis. Results indicated that the relatively high contents of cadmium, lead,antimony, and zinc in the soils at 250 m and 750–1250 m away from the MSW incinerators were related to MSW incineration, while the elevated contents of the other four HMs were associated with other anthropogenic activities. Based on Pb isotope analysis, the contribution ratio of MSW incineration(which had been operated for more than 14 years)to the accumulation of Pb in soil was approximately 10% on average, which was lower than coal combustion only. Incinerator emissions of Pb could have a measurable effect on the soil contamination within a limited area(≤1500 m).
文摘The influence of temperature on the performance of anaerobic reactors for treating the organic fraction of municipal sohd waste （OFMSW） was studied. Batch digestion of OFMSW was carded out for 32 d at different temperature （25℃, 35℃, 45℃ and 55℃） conditions for total solid concentrations （TS） 17% with the ratio of total organic carbon to nitrogen （C/N） being, 25：1 respectively, while keeping other parameters constant such as inoculum, start-up pH, reactor volume （2 L） and so on. Temperature can influence the methanogenic bacteria activity, accordingly inhibiting the OFMSW biodegradation and stabilization efficiency. Anaerobic reactors excelled at TS reduction, total volatile solid reduction, chemical oxygen demand reduction, increasing cumulative biogas production, whose rate was at temperature （35℃ and 55℃） conditions. Methane concentration in the biogas was above 65% in four reactors. In addition, the fluctuation of temperatures resulted in the biogas production variation. The data obtained indicated that temperature had a significant influence on anaerobic process.
文摘Transfer station(TS)is an integral part of present-day municipal solid waste(MSW)management systems.To provide information for the incorporation of waste facilities within the current integrated waste management system,the authors measured the existing environmental quality at five MSW TSs.Discharged wastewater,air,and noise were monitored and assayed at the five TSs in Beijing in 2001-2006 during rainy seasons(RSs)and dry seasons(DSs).Except Ammonia(NH_3)and hydrogen sulfide(H_2S),the analytical results of...
基金supported by the Hi-Tech Research and Development Program (863) of China (No. 2012AA06A116)
文摘The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator （MSWI） fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas. The reaction between fly ash and 100% CO2 was relatively fast; the uptake of CO2 reached 87 g CO2/kg ash, and the sequestered CO2 could be entirely released at high temperatures. When CO2 content was reduced to 12%, the reaction rate decreased; the uptake fell to 41 g CO2/kg ash, and 70.7% of the sequestered CO2 could be released. With 12% CO2 in the presence of SO2, the reaction rate significantly decreased; the uptake was just 17 g CO2/kg ash, and only 52.9% of the sequestered CO2 could be released. SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.
基金the DAAD Sandwich Model Scholarships for Master's Students of the IITs and IIMs, 2016/17, who funded the research stay of Mr.Pravesh Tamang in Germany (Personal Ref No: 91635161)
文摘The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(～2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.
文摘In Belgium,the Boom clay was selected as a potential host formation for the disposal of high-level radioactive waste（HLW）.To demonstrate the suitability of Boom clay for bearing thermal load induced by the HLW,a large-scale in-situ heater test,called PRACLAY heater test,will be conducted in the underground research laboratory（URL） in Mol.Owing to the limitations of the test（a short period of time compared with that considered in a real repository,different boundary conditions,etc.）,the test is designed to simulate,in a conservative way,the most critical state and phenomena that could occur in the host rock.The PRACLAY gallery was excavated at the end of 2007;the heating phase will begin in 2010 and will last for at least 10 years.The PRACLAY gallery itself leaves an opportunity to study the possibilities of sealing a disposal drift in Boom clay and testing the feasibility of hydraulic cut-off of any preferential pathway to the main access gallery through the excavation damage zone（EDZ） and the lining with a seal in a horizontal drift（horizontal seal）.Indeed,this is a generic problem for all deep geological disposal facilities for HLW.An annular seal made of compacted swelling bentonite will be installed in the front of the heated part of the PRACLAY gallery for these purposes.This paper provides detailed considerations on the thermo-hydro-mechanical（THM） boundary conditions for the design of the PRACLAY heater test and the seal test with the support of numerical calculations.It is believed that these important items considered in the PRACLAY heater test design also constitute key issues for the repository design.The outcome of the PRACLAY heater test will be an important milestone for the Belgian repository design.
