Developing low-cost and green simultaneous desulfurization and denitrification technologies is of great significance for sulfur dioxide(SO_(2))and nitrogen oxide(NO_(x))emission control at low temperatures,especially ...Developing low-cost and green simultaneous desulfurization and denitrification technologies is of great significance for sulfur dioxide(SO_(2))and nitrogen oxide(NO_(x))emission control at low temperatures,especially for small and medium-sized coal-fired boilers and furnaces.Herein,phosphorus sludge,an industrial waste from the production process of yellow phosphorus,has been developed to simultaneously eliminate SO_(2)and NO_(x)from coal-fired flue gas.The key factors affecting the experimental results indicate that desulfurization and denitrification efficiency of over 95%can be achieved at a low temperature of 55℃.Further,the absorption mechanism was investigated by characterizing the solid and liquid phases of the phosphorus sludge during the absorption process.The efficient removal of SO_(2)is attributed to the abundance of iron(Fe^(3+))and manganese(Mn^(2+))in the absorbent.SO_(2)can be rapidly catalyzed and converted to SO_(4)^(2-)by them.The key to NOx removal is the oxidation of NO toward watersoluble high-valent nitrogen oxides by oxidizing reactive substances induced via yellow phosphorus,which are then absorbed by water and converted to NO_(3)^(-).Meanwhile,yellow phosphorus is oxidized to phosphoric acid(H_(3)PO_(4)).The spent absorption slurry can be reused through wet process phosphoric acid production,as it contains sulfuric acid(H_(2)SO_(4)),nitric acid(HNO_(3)),and H_(3)PO_(4).Accordingly,this is a technology with broad application prospects.展开更多
This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobi...This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.展开更多
In this study,hydrogels were prepared from municipal sludge to recycle and realize the value-added utilization of the carbon components in this abundant waste material.The carbon sources were extracted from the munici...In this study,hydrogels were prepared from municipal sludge to recycle and realize the value-added utilization of the carbon components in this abundant waste material.The carbon sources were extracted from the municipal sludge using synthesised nano CaO_(2)as an oxidant,and the carbon sources were graft copolymerised with acrylic acid monomer using N,N′-methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator.The factors influencing the hydrogel preparation were investigated by single-factor experiments.Based on the results of the single-factor experiments,a hydrogel with a swelling ratio of up to 19768.4%at 12 h was prepared with an oxidant dosage of 0.20 g,a monomer dosage of 5.8 g,a neutralisation degree of the monomer of 70%,an initiator dosage of 0.15 g,and a crosslinking agent dosage of 0.15 g.The hydrogel preparation conditions were optimized using the response surface method,and the interactions between the different reaction conditions were analysed to obtain the best preparation conditions.X-ray diffraction results showed that hydrogels were amorphous in structure.Scanning electron microscopy images showed that the SiO_(2)particles from the sludge acted as crosslinking points between different layers of hydrogel chains.The crosslinking polymerisation and crosslinking agent worked together to form hydrogels with an inorganic-organic double network structure,and this structure was highly stretchable,resulting in hydrogels with good swelling properties.展开更多
Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants.Among recent studies,pilot and field tests showed that chemical conditioning combined with vacuum preloading ...Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants.Among recent studies,pilot and field tests showed that chemical conditioning combined with vacuum preloading can effectively treat municipal sludge.To further understand the drainage and consolidation characteristics of the conditioning sludge during vacuum preloading,a large deformation nonlinear numerical simulation model based on the equal strain condition was developed to simulate and analyze the pilot and field tests,whereas the simulation results were not satisfactory.The results of the numerical analysis of the pilot test showed that the predicted consolidation degree was greater than that measured by the field tests,which is attributed to the relatively low permeability layer formed during the preloading process of the prefabricated vertical drain.To better reflect the consolidation process of the conditioned sludge,a simplified analysis method considering the low permeability layer around the prefabricated vertical drain was proposed.The initial permeability coefficient of the low permeability layer is determined via numerical simulations using finite difference method.The predicted settlement curve was in good agreement with the measured results,which indicated that the numerical simulation based on the equal strain condition considering the relatively low permeability layer can better analyze the consolidation process of ferric chloride-conditioning sludge with vacuum preloading.展开更多
Taking an industrial sludge and its preparation of sludge wrap shell aggregates(WSAs)instead of sand to prepare baking-free brick as the research object,the development law of mechanical properties and the influence m...Taking an industrial sludge and its preparation of sludge wrap shell aggregates(WSAs)instead of sand to prepare baking-free brick as the research object,the development law of mechanical properties and the influence mechanism of macro and micro characteristic parameters of the bricks under different sludge and WSAs replacement rates were studied through the macroscopic mechanical properties test,with the help of nuclear magnetic resonance(NMR),transmission electron microscopy-energy spectrum and other testing technology and pores and cracks analysis system(PCAS)software.The results showed that the compressive strength of each sample decreased with the increase of sludge content.When the sludge content was less than 30%,it was mainly affected by the water-binder ratio.When the sludge content was more than 30%,it was mainly affected by the sludge content.At the age of 7 days,with the increase in replacement rate of WSAs,the compressive strength of the S10 and S30 groups was higher than that of the control group.The compressive strength of the S50 experimental group was 30.38 MPa,and the loss of compressive strength was slight compared with the control group.The water absorption rate of the 28 days S100 experimental group increased by 10.71%compared with the control group.When the content of WSAs was less than 50%,the holes above 0.1μm in the brick can be reduced and transformed into smaller holes,with a decreasing trend of the plane porosity of the brick.The microscopic results of the baking-free brick showed that the three-phase system of WSAs-interface transition area-mortar was poorly bonded and delaminated compared with the gravel aggregate-interface transition area-mortar system,and damage was more likely to occur in the WSAs and interface transition area.The above results show that it is feasible to use sludge and WSAs instead of sand for the preparation of baking-free bricks.This technology not only solves the problem of sludge disposal,but also protects the over-exploitation of mineral resources,and the technology has a broad application prospect and market value.展开更多
Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in thi...Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in this study to improve the efficiency of pretreatment method.Direct thermal hydrolysis(TH),pasteurized thermal hydrolysis(PTH),and alkaline pasteurized thermal hydrolysis(PTH+CaO and PTH+NaOH)methods were used to treat EAS.Each method was compared and analyzed in terms of dissolution in ammonium nitrogen(NH_(4)^(+)-N)and soluble COD(SCOD)in EAS.Furthermore,the removal of tetracycline resistance genes(TRGs)and class 1 transposon gene intI1 from EAS was investigated.The NH_(4)^(+)-N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH.However,the removal efficiency of total TRGs and intI1 between the groups was comparable.The SCOD concentration of the PTH+NaOH group was 4.37 times higher than that of the PTH group,and the removal efficiency of total TRGs was increased by 9.52%compared with that by PTH.The NH_(4)^(+)-N and SCOD concentrations of the PTH+CaO group could reach 85.04%and 92.14%of the PTH+NaOH group,but the removal efficiency of total TRGs by PTH+CaO was 19.78%lower than that by PTH+NaOH.Thus,to reduce the financial cost in actual operation,lime(CaO)can be used instead of a strong alkali(NaOH),and pasteurized steam at 70℃ instead of conventional high-temperature heating to treat EAS.This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.展开更多
To fully utilize secondary resources,it will inevitably generate a large amount of deinking sludge using waste paper as raw material for paper making.The sludge contains small fibers and dissolved substances of variou...To fully utilize secondary resources,it will inevitably generate a large amount of deinking sludge using waste paper as raw material for paper making.The sludge contains small fibers and dissolved substances of various chemicals.After adding flocculant and settling treatment,deinked sludge is formed.However,its organic matter content can reach a high level of 40%to 50%,and it can also be reused,effectively avoiding the harmful impact of papermaking sludge on the environment.展开更多
In the town of Mamou,all homes with sanitation systems are equipped with autonomous installations not connected to a sewer network.The emptying service is provided by manual emptiers and by the living environment and ...In the town of Mamou,all homes with sanitation systems are equipped with autonomous installations not connected to a sewer network.The emptying service is provided by manual emptiers and by the living environment and sanitation service of the urban municipality which has a single 6 m^(3)truck.The objective of this work is to determine the quantity of fecal sludge produced within the city for sustainable management.The methodology adopted is based on a field survey and the use of three methods for evaluating the quantities of sludge(specific production,quantity of sludge collected by the sludge truck and the total production of sludge produced in the various sludge works).The results obtained show that,out of the 2,940 sanitation works identified,2,936 works have been emptied at least once since their construction.Then 2,307 structures are emptied manually or 78.57%,against;619 structures emptied mechanically or 21.08%.The structures are emptied on average every 3 years for septic tanks and every 5 years for dry latrines.The specific production of sludge is 685,241,532 m^(3)/year;the production of sludge by the mechanical emptying technique varies from 588,641.57 m^(3)/year to 724,800.46 m^(3)/year and the production of sludge by manual emptying is 1,573,709.33 m^(3)/year,for a total quantity of sludge produced including between 2,162,350 m^(3)/year to 685,241,531.9 m^(3)/year.展开更多
The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to ent...The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.展开更多
Coal sludge slurry(CSS) is an alternative fuel and a potential competitive method for sludge reduction.Based on the researches of coal water slurry, we studied CSSs by using a wet-grinding process with different types...Coal sludge slurry(CSS) is an alternative fuel and a potential competitive method for sludge reduction.Based on the researches of coal water slurry, we studied CSSs by using a wet-grinding process with different types of regional municipal sludge(sludge) in an orthogonal experiment. The sludge type,sludge mixing proportion, dosage of dispersant, and grinding time were tested in this study. The results show that water content and its occurrence characteristics in the sludge have primary hindering influences on slurry ability. The range of fixed-viscosity concentrations with raw wet sludge is from 50.78%to 44.40%(by weight), while the range is from 53.35% to 51.51%(by weight) with dry sludge. All of the CSSs exhibit shear-thinning behaviors with different variation trends, especially the CSSs with more than 15%(by weight) raw wet sludge in it. Adding the same proportion of raw wet sludge increases the thixotropic properties of CSSs and the highest area of thixotropy loop is 3065 Pa/s, while the highest value of dry sludge is 1798 Pa/s. Hydrophilic group plays an important role in adsorbing water and building three-dimension networks with other particles, which is the main reason for CSS properties.Therefore, the mechanism can be used to find the way for making high quality CSS.展开更多
In order to investigate the effect of temperature on activated sludge systems,sludge settleability,nitrogen and phosphorus removal processes were investigated by changing temperature variation patterns using 4 sequenc...In order to investigate the effect of temperature on activated sludge systems,sludge settleability,nitrogen and phosphorus removal processes were investigated by changing temperature variation patterns using 4 sequencing batch reactors (SBR).The results showed that no matter temperature changes in the range of 15-22 ℃ (decrease or increase) gradually or sharply,it has little effect on nitrogen and phosphorus removal processes.But when temperature decreases to 12 ℃,biochemical reactions will be inhibitted obviously.At least 1 sludge retention time (SRT) is needed for nitrification adapt to new temperature envirionment,and more time is necessary for phosphorus removal process.When temperature increases from 12 ℃ to 22 ℃ sharply,nitrification process deteriorates seriously,but phosphorus removal process shows no change.In addition,sludge settleability deteriorates when temperature changes sharply (decrease or increase),but the reasons are different.Under temperature decrease condition,it is mainly caused by the increase of accumulated extracellular polymeric substances (EPS).Under temperature increase condition,the loosing sludge flocs' configuration is the main reason.It should be pointed out that the filamentous bacteria content during the entire experiment keeps almost constant,and the sludge settleability variations are the reflection of the change of sludge physicochemical characteristics.展开更多
This study investigated the use of microbial analysis as a bioremediation option for remediating petroleum sludge, which is part of the waste stream generated in the petroleum industry. The aim is to reduce environmen...This study investigated the use of microbial analysis as a bioremediation option for remediating petroleum sludge, which is part of the waste stream generated in the petroleum industry. The aim is to reduce environmental burden caused by the discharge of untreated sludge. Sludge sample was cultured in other to isolate microorganisms for the sludge treatment. The selected strain of the organisms after screening were Aspergillus flavus, Aspergillus niger, Verticillus sp, Penicillum sp, and Microsporium audouinii. Bioreactors (labeled A, B, C, D and O) were designed for the treatment of petroleum sludge. These reactors contain 2.0 × 10<sup>-2</sup> m<sup>3</sup> of the diluted sludge samples and the isolated organisms for the treatment process. On a weekly basis, the control reactors received 1.5 × 10<sup>-3</sup> m<sup>3</sup> of fresh and saline water respectively. After 12 weeks of treatment, sludge physicochemical characteristics showed distinct variations. From the result, reactor D was the best in terms of remediating the sludge as compared to other reactors. Friedman non-parametric test was performed to check if the weeks of treatment affected the reduction of the total hydrocarbon content (THC) in the five reactors and also checked for significant differences in the THC after treatments. The drop in the THC of the treated sludge ranged from 56.0% to 67.3%. These results showed the possibility of enhanced biodegradation of petroleum sludge by hydrocarbon utilizing microorganisms (fungi).展开更多
Wastewater sludge creates a difficult environmental problem for many large cities.This study developed a three-phase innovative strategy for sludge treatment and reduction,including thermal hydrolysis,fungal fermentat...Wastewater sludge creates a difficult environmental problem for many large cities.This study developed a three-phase innovative strategy for sludge treatment and reduction,including thermal hydrolysis,fungal fermentation,and anaerobic digestion.Increasing the temperature during the treatment from 140 to 180℃ significantly improved the sludge reduction and organic release efficiencies(p<0.05,one-way analysis of variance(ANOVA)for the triplicate experiments at each temperature).After two cycles of thermal hydrolysis,the overall volatile solid reduction ratios of the sludge were 36.6%,47.7%,and 58.5%for treatment at 140,160,and 180℃,respectively,and the total organic carbon(TOC)conversion efficiency reached 28.0%,38.0%,and 45.1%,respectively.The highest concentrations of carbohydrates and proteins were obtained at 160℃ in sludge liquor,whereas the amount of humic substances significantly increased for the treatment at 180℃(p<0.05,one-way ANOVA for the triplicate experiments at each temperature)due to the Maillard reaction.Fungal fermentation of the hydrolyzed sludge liquor with Aspergillus niger converted the waste organics to valuable fiber materials.The biomass concentration of fungal hyphae reached 1.30 and 1.27 g·L^(-1) in the liquor of sludge treated at 140 and 160C,corresponding to organic conversion ratios of 24.6%and 24.0%,respectively.The fungal hyphae produced from the sludge liquor can be readily used for making papers or similar value-added fibrous products.The paper sheets made of hyphae fibers had a dense structure and strong strength with a tensile strength of 10.75 N·m·g^(-1).Combining fungal fermentation and anaerobic digestion,the overall organic utilization efficiency can exceed 75%for the liquor of sludge treated at 160℃.展开更多
Viscous sludge bulking is a rare phenomenon in activated sludge process.The performances of nutrients removal were investigated with normal sludge and viscous bulking sludge.The results showed that when COD loading an...Viscous sludge bulking is a rare phenomenon in activated sludge process.The performances of nutrients removal were investigated with normal sludge and viscous bulking sludge.The results showed that when COD loading and C/N ratio were around 0.13 mg COD/(mg MLSS·d)and 7.67,the effect of viscous sludge bulking on the maximum specific oxidation rates of NH_(4)^(+)⁃N was very little,while the maximum specific oxidation rates of NO_(2)^(-)⁃N decreased from 24.69 mg/(g·h)to 1.20 mg/(g·h).Compared with normal sludge,viscous bulking sludge had bigger particle size and more extracellular polymeric substances(EPS).The mass transfer resistance in sludge flocs might be the main cause of the difference in NO-2⁃N oxidation rates.Therefore,this study demonstrates that viscous sludge bulking is beneficial to enhance simultaneous nitrification and denitrification(SND),and excessive EPS will exhibit storage function during phosphorus removal process.展开更多
[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as ...[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as its influencing factors,so as to discuss the optimal conditions of sludge granulation.[Result]Through the static culture outside of IC reactor and dynamic culture in IC reactor,granular sludge appeared within a training cycle,with particle size of 1.0-1.5 mm.In IC reactor,when COD concentration of influent water was 5 000 mg /L,rising velocity was 0.9 m /h,pH was around 7,and auxiliary materials (like flocculant and active carbon) and mature granular sludge were added to the actor during the training process,the granulation process of sludge was accelerated.[Conclusion]The research could provide references for the rapid start-up of IC reactor.展开更多
This work takes sludge drying and incineration and pollutant discharge characteristics as the main line of research.With sludge dewatered by a certain sewage plant in southern Jiangsu using machinery and chemical cond...This work takes sludge drying and incineration and pollutant discharge characteristics as the main line of research.With sludge dewatered by a certain sewage plant in southern Jiangsu using machinery and chemical conditioners selected as the research object,the influencing factors such as particle size,drying temperature and sludge reverse-mixing ratio in the sludge drying process were mainly explored,and the best working conditions of sludge drying were further analyzed.On this basis,in-depth research was carried out on the pollutants such as NO_(x),SO_(2),HCl,CO and other pollutants generated in the sludge incineration process by investigating the incineration temperature,sewage,the sludge moisture content and excess air coefficient.The results showed that the best conditions for sludge drying were as follows:particle size 3.5 mm,temperature 210℃and reverse-mixing ratio 25,and the cumulative drying time of the sludge 445.21 min.Through the research on the pollutant emission characteristics of sludge incineration,it was found that the incineration temperature and the moisture content of the sludge had a greater impact on the emission concentrations of NO_(x),SO_(2),HCl,and CO.Among them,the incineration temperature was the key factor that affected the generation of NO_(x),SO_(2),HCl,and CO.展开更多
For the problem as high energy consumption and sludge increment during the municipal sludge management process with advanced oxidation technology of sulfate radical, the <span style="white-space:nowrap;"&...For the problem as high energy consumption and sludge increment during the municipal sludge management process with advanced oxidation technology of sulfate radical, the <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub></span> composite CaO reaction system was set up. Meanwhile, systematical studies had been carried out for coordinated conditioning of municipal concentrated sludge. The scientific process parameters were determined with the help of sludge capillary suction time, sewage sludge moisture content and other core indicators and the effect of traditional polyacrylamide flocculation method, Fenton method and activated persulfate method were compared. The results showed that in the neutral concentrated sludge conditioning, there were outstanding advantages for <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub> </span>composite CaO reaction system compared with Fenton, CPAM, and SO<sup>-</sup><sub style="margin-left:-7px;">4</sub><span style="white-space:normal;"></span> methods and the optimal parameters for dosage were as follows: <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub></span>: 80 - 120 mg<span style="white-space:nowrap;">·</span>g<sup>-1</sup> DS, n(Fe2+):n(SPS) = 0.8:1, CaO: 200 mg<span style="white-space:nowrap;">·</span>g<sup>-1</sup> DS. To achieve similar performance index, the dosage of Fe<sup>2+</sup> per ton for sludge could be reduced by 20%, the loss rate for iron in filtrate was 0.5%, dewatering of sludge by suction filtration was within 50 s and the moisture content for dewatering cake was 53.7%, which significantly improved the economy and practicability of SO<sup>-</sup><sub style="margin-left:-7px;">4</sub> <span style="white-space:normal;"></span>advanced oxidation technology, and the results were expected to form a useful supplement to the popularization and application of SO<sup>-</sup><sub style="margin-left:-7px;">4</sub><span style="white-space:normal;"></span> advanced oxidation technology.展开更多
A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate poll...A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate pollution. The recovery of Cu, Ni, Zn and Cr is 94%, 91%, 90% and 95%, respectively. The ammonia was recycled by the simplified process of CaO caustic distillation. The precipitated product of Cu, Ni and Zn obtained from caustic distillation of ammonia was separated by extraction or high\|pressure hydrogen reduction in an autoclave. The qualified metal salt products were obtained through extraction. The rich chromium residue from coordinative disposal was subjected to recover Cr by hydrothermal oxidation in NaOH medium and Fe\-3O\-4 was synthesized by wet methods from the residue produced by extracting Cr. Cr was a stable chemical fixed in Fe\-3O\-4 and harmless. The recovery process has been used in a pilot plant with sludge production capacity of 2000 t/a.展开更多
BACKGROUND:The process of microcrystallization,its sequel and the assessment of nucleation time is ignored.This systematic review aimed to highlight the importance of biliary microlithiasis,sludge,and crystals,and the...BACKGROUND:The process of microcrystallization,its sequel and the assessment of nucleation time is ignored.This systematic review aimed to highlight the importance of biliary microlithiasis,sludge,and crystals,and their association with gallstones,unexplained biliary pain,idiopathic pancreatitis, and sphincter of Oddi dysfunction.DATA SOURCES:Three reviewers performed a literature search of the PubMed database.Key words used were"biliary microlithiasis","biliary sludge","bile crystals","cholesterol crystallisation","bile microscopy","microcrystal formation of bile","cholesterol monohydrate crystals","nucleation time of cholesterol","gallstone formation","sphincter of Oddi dysfunction"and"idiopathic pancreatitis".Additional articles were sourced from references within the studies from the PubMed search.RESULTS:We found that biliary microcrystals account for almost all patients with gallstone disease,7%to 79%with idiopathic pancreatitis,83%with unexplained biliary pain, and 25%to 60%with altered biliary and pancreatic sphincter function.Overall,the detection of biliary microcrystals in gallstone disease has a sensitivity ranging from 55%to 87%and a specificity of 100%.In idiopathic pancreatitis,the presence of microcrystals ranges from 47%to 90%.A nucleation time less than 10 days in hepatic bile or ultra-filtered gallbladder bile has a specificity of 100%for cholesterol gallstone disease.CONCLUSIONS:Biliary crystals are associated with gallstone disease,idiopathic pancreatitis,sphincter of Oddi dysfunction, unexplained biliary pain,and post-cholecystectomy biliary pain.Pathways of cholesterol super-saturation,crystallisation, and gallstone formation have been described with scientificsupport.Bile microscopy is a useful method to detect microcrystals and the assessment of nucleation time is a good method of predicting the risk of cholesterol crystallisation.展开更多
基金The National Natural Science Foundation of China (22068019)Yunnan Major Scientific and Technological Projects (202202AG050001)
文摘Developing low-cost and green simultaneous desulfurization and denitrification technologies is of great significance for sulfur dioxide(SO_(2))and nitrogen oxide(NO_(x))emission control at low temperatures,especially for small and medium-sized coal-fired boilers and furnaces.Herein,phosphorus sludge,an industrial waste from the production process of yellow phosphorus,has been developed to simultaneously eliminate SO_(2)and NO_(x)from coal-fired flue gas.The key factors affecting the experimental results indicate that desulfurization and denitrification efficiency of over 95%can be achieved at a low temperature of 55℃.Further,the absorption mechanism was investigated by characterizing the solid and liquid phases of the phosphorus sludge during the absorption process.The efficient removal of SO_(2)is attributed to the abundance of iron(Fe^(3+))and manganese(Mn^(2+))in the absorbent.SO_(2)can be rapidly catalyzed and converted to SO_(4)^(2-)by them.The key to NOx removal is the oxidation of NO toward watersoluble high-valent nitrogen oxides by oxidizing reactive substances induced via yellow phosphorus,which are then absorbed by water and converted to NO_(3)^(-).Meanwhile,yellow phosphorus is oxidized to phosphoric acid(H_(3)PO_(4)).The spent absorption slurry can be reused through wet process phosphoric acid production,as it contains sulfuric acid(H_(2)SO_(4)),nitric acid(HNO_(3)),and H_(3)PO_(4).Accordingly,this is a technology with broad application prospects.
基金supported by the National Natural Science Foundation of China(No.41276067)the Air Liquide(China)R&D Co.,Ltd.(No.20200216).
文摘This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.
基金support from the National Visiting Scholar Program for Key Young Teachers of Central and Western Universities,the Ministry of Education(19042)the Key Science and Technology Project of Henan Province(212102310064)the National Innovation and the Entrepreneurship Training Program for College Students,Ministry of Education(202111517002).
文摘In this study,hydrogels were prepared from municipal sludge to recycle and realize the value-added utilization of the carbon components in this abundant waste material.The carbon sources were extracted from the municipal sludge using synthesised nano CaO_(2)as an oxidant,and the carbon sources were graft copolymerised with acrylic acid monomer using N,N′-methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator.The factors influencing the hydrogel preparation were investigated by single-factor experiments.Based on the results of the single-factor experiments,a hydrogel with a swelling ratio of up to 19768.4%at 12 h was prepared with an oxidant dosage of 0.20 g,a monomer dosage of 5.8 g,a neutralisation degree of the monomer of 70%,an initiator dosage of 0.15 g,and a crosslinking agent dosage of 0.15 g.The hydrogel preparation conditions were optimized using the response surface method,and the interactions between the different reaction conditions were analysed to obtain the best preparation conditions.X-ray diffraction results showed that hydrogels were amorphous in structure.Scanning electron microscopy images showed that the SiO_(2)particles from the sludge acted as crosslinking points between different layers of hydrogel chains.The crosslinking polymerisation and crosslinking agent worked together to form hydrogels with an inorganic-organic double network structure,and this structure was highly stretchable,resulting in hydrogels with good swelling properties.
基金acknowledge the financial support from The National Natural Science Foundation No.Gk321002Foundation of Nanjing Hydraulic Research Institute No.Y320012.
文摘Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants.Among recent studies,pilot and field tests showed that chemical conditioning combined with vacuum preloading can effectively treat municipal sludge.To further understand the drainage and consolidation characteristics of the conditioning sludge during vacuum preloading,a large deformation nonlinear numerical simulation model based on the equal strain condition was developed to simulate and analyze the pilot and field tests,whereas the simulation results were not satisfactory.The results of the numerical analysis of the pilot test showed that the predicted consolidation degree was greater than that measured by the field tests,which is attributed to the relatively low permeability layer formed during the preloading process of the prefabricated vertical drain.To better reflect the consolidation process of the conditioned sludge,a simplified analysis method considering the low permeability layer around the prefabricated vertical drain was proposed.The initial permeability coefficient of the low permeability layer is determined via numerical simulations using finite difference method.The predicted settlement curve was in good agreement with the measured results,which indicated that the numerical simulation based on the equal strain condition considering the relatively low permeability layer can better analyze the consolidation process of ferric chloride-conditioning sludge with vacuum preloading.
基金the Natural Science Foundation of Henan Province(202300410270)Graduate Education Innovation Program fund of North China University of Water Resources and Electric Power(YK-2021-49).
文摘Taking an industrial sludge and its preparation of sludge wrap shell aggregates(WSAs)instead of sand to prepare baking-free brick as the research object,the development law of mechanical properties and the influence mechanism of macro and micro characteristic parameters of the bricks under different sludge and WSAs replacement rates were studied through the macroscopic mechanical properties test,with the help of nuclear magnetic resonance(NMR),transmission electron microscopy-energy spectrum and other testing technology and pores and cracks analysis system(PCAS)software.The results showed that the compressive strength of each sample decreased with the increase of sludge content.When the sludge content was less than 30%,it was mainly affected by the water-binder ratio.When the sludge content was more than 30%,it was mainly affected by the sludge content.At the age of 7 days,with the increase in replacement rate of WSAs,the compressive strength of the S10 and S30 groups was higher than that of the control group.The compressive strength of the S50 experimental group was 30.38 MPa,and the loss of compressive strength was slight compared with the control group.The water absorption rate of the 28 days S100 experimental group increased by 10.71%compared with the control group.When the content of WSAs was less than 50%,the holes above 0.1μm in the brick can be reduced and transformed into smaller holes,with a decreasing trend of the plane porosity of the brick.The microscopic results of the baking-free brick showed that the three-phase system of WSAs-interface transition area-mortar was poorly bonded and delaminated compared with the gravel aggregate-interface transition area-mortar system,and damage was more likely to occur in the WSAs and interface transition area.The above results show that it is feasible to use sludge and WSAs instead of sand for the preparation of baking-free bricks.This technology not only solves the problem of sludge disposal,but also protects the over-exploitation of mineral resources,and the technology has a broad application prospect and market value.
基金supported by the Key R&D Projects of the Sichuan Provincial Department of Science and Technology in 2022 (No.2022YFS0457)Innovation and Entrepreneurship Training Program for College Students (No.202210649050).
文摘Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in this study to improve the efficiency of pretreatment method.Direct thermal hydrolysis(TH),pasteurized thermal hydrolysis(PTH),and alkaline pasteurized thermal hydrolysis(PTH+CaO and PTH+NaOH)methods were used to treat EAS.Each method was compared and analyzed in terms of dissolution in ammonium nitrogen(NH_(4)^(+)-N)and soluble COD(SCOD)in EAS.Furthermore,the removal of tetracycline resistance genes(TRGs)and class 1 transposon gene intI1 from EAS was investigated.The NH_(4)^(+)-N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH.However,the removal efficiency of total TRGs and intI1 between the groups was comparable.The SCOD concentration of the PTH+NaOH group was 4.37 times higher than that of the PTH group,and the removal efficiency of total TRGs was increased by 9.52%compared with that by PTH.The NH_(4)^(+)-N and SCOD concentrations of the PTH+CaO group could reach 85.04%and 92.14%of the PTH+NaOH group,but the removal efficiency of total TRGs by PTH+CaO was 19.78%lower than that by PTH+NaOH.Thus,to reduce the financial cost in actual operation,lime(CaO)can be used instead of a strong alkali(NaOH),and pasteurized steam at 70℃ instead of conventional high-temperature heating to treat EAS.This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.
文摘To fully utilize secondary resources,it will inevitably generate a large amount of deinking sludge using waste paper as raw material for paper making.The sludge contains small fibers and dissolved substances of various chemicals.After adding flocculant and settling treatment,deinked sludge is formed.However,its organic matter content can reach a high level of 40%to 50%,and it can also be reused,effectively avoiding the harmful impact of papermaking sludge on the environment.
文摘In the town of Mamou,all homes with sanitation systems are equipped with autonomous installations not connected to a sewer network.The emptying service is provided by manual emptiers and by the living environment and sanitation service of the urban municipality which has a single 6 m^(3)truck.The objective of this work is to determine the quantity of fecal sludge produced within the city for sustainable management.The methodology adopted is based on a field survey and the use of three methods for evaluating the quantities of sludge(specific production,quantity of sludge collected by the sludge truck and the total production of sludge produced in the various sludge works).The results obtained show that,out of the 2,940 sanitation works identified,2,936 works have been emptied at least once since their construction.Then 2,307 structures are emptied manually or 78.57%,against;619 structures emptied mechanically or 21.08%.The structures are emptied on average every 3 years for septic tanks and every 5 years for dry latrines.The specific production of sludge is 685,241,532 m^(3)/year;the production of sludge by the mechanical emptying technique varies from 588,641.57 m^(3)/year to 724,800.46 m^(3)/year and the production of sludge by manual emptying is 1,573,709.33 m^(3)/year,for a total quantity of sludge produced including between 2,162,350 m^(3)/year to 685,241,531.9 m^(3)/year.
基金National Natural Science Foundation of China(No.51478099)Scientific Research Foundation for Returned Overseas Chinese Scholars of China(No.SEM-11W11329)
文摘The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.
基金supported by the National Natural Science Foundation of China (Nos. 51204179, 51204182)the Natural Science Foundation of Jiangsu Province of China (No. BK20141242)the Fundamental Research Funds for the Central Universities of China (No. 2014XT05)
文摘Coal sludge slurry(CSS) is an alternative fuel and a potential competitive method for sludge reduction.Based on the researches of coal water slurry, we studied CSSs by using a wet-grinding process with different types of regional municipal sludge(sludge) in an orthogonal experiment. The sludge type,sludge mixing proportion, dosage of dispersant, and grinding time were tested in this study. The results show that water content and its occurrence characteristics in the sludge have primary hindering influences on slurry ability. The range of fixed-viscosity concentrations with raw wet sludge is from 50.78%to 44.40%(by weight), while the range is from 53.35% to 51.51%(by weight) with dry sludge. All of the CSSs exhibit shear-thinning behaviors with different variation trends, especially the CSSs with more than 15%(by weight) raw wet sludge in it. Adding the same proportion of raw wet sludge increases the thixotropic properties of CSSs and the highest area of thixotropy loop is 3065 Pa/s, while the highest value of dry sludge is 1798 Pa/s. Hydrophilic group plays an important role in adsorbing water and building three-dimension networks with other particles, which is the main reason for CSS properties.Therefore, the mechanism can be used to find the way for making high quality CSS.
基金Sponsored by the Natural Science Foundation of China (Grant No.50778005)the National Key Science and Technology Special Projects (Grant No.2008ZX07209-003,2008ZX07314-008-01)
文摘In order to investigate the effect of temperature on activated sludge systems,sludge settleability,nitrogen and phosphorus removal processes were investigated by changing temperature variation patterns using 4 sequencing batch reactors (SBR).The results showed that no matter temperature changes in the range of 15-22 ℃ (decrease or increase) gradually or sharply,it has little effect on nitrogen and phosphorus removal processes.But when temperature decreases to 12 ℃,biochemical reactions will be inhibitted obviously.At least 1 sludge retention time (SRT) is needed for nitrification adapt to new temperature envirionment,and more time is necessary for phosphorus removal process.When temperature increases from 12 ℃ to 22 ℃ sharply,nitrification process deteriorates seriously,but phosphorus removal process shows no change.In addition,sludge settleability deteriorates when temperature changes sharply (decrease or increase),but the reasons are different.Under temperature decrease condition,it is mainly caused by the increase of accumulated extracellular polymeric substances (EPS).Under temperature increase condition,the loosing sludge flocs' configuration is the main reason.It should be pointed out that the filamentous bacteria content during the entire experiment keeps almost constant,and the sludge settleability variations are the reflection of the change of sludge physicochemical characteristics.
文摘This study investigated the use of microbial analysis as a bioremediation option for remediating petroleum sludge, which is part of the waste stream generated in the petroleum industry. The aim is to reduce environmental burden caused by the discharge of untreated sludge. Sludge sample was cultured in other to isolate microorganisms for the sludge treatment. The selected strain of the organisms after screening were Aspergillus flavus, Aspergillus niger, Verticillus sp, Penicillum sp, and Microsporium audouinii. Bioreactors (labeled A, B, C, D and O) were designed for the treatment of petroleum sludge. These reactors contain 2.0 × 10<sup>-2</sup> m<sup>3</sup> of the diluted sludge samples and the isolated organisms for the treatment process. On a weekly basis, the control reactors received 1.5 × 10<sup>-3</sup> m<sup>3</sup> of fresh and saline water respectively. After 12 weeks of treatment, sludge physicochemical characteristics showed distinct variations. From the result, reactor D was the best in terms of remediating the sludge as compared to other reactors. Friedman non-parametric test was performed to check if the weeks of treatment affected the reduction of the total hydrocarbon content (THC) in the five reactors and also checked for significant differences in the THC after treatments. The drop in the THC of the treated sludge ranged from 56.0% to 67.3%. These results showed the possibility of enhanced biodegradation of petroleum sludge by hydrocarbon utilizing microorganisms (fungi).
基金This work was supported by the Shenzhen Municipal Science and Technology Innovation Council of the Shenzhen Government(JCYJ20170307153821435 and JCYJ20180508152004176)the National Natural Science Foundation of China(51678333)+1 种基金the Research Grants Council of the Hong Kong Government(17261916,T21-711/16R)the Development and Reform Commission of Shenzhen Municipality(Urban Water Recycling and Environment Safety Program).
文摘Wastewater sludge creates a difficult environmental problem for many large cities.This study developed a three-phase innovative strategy for sludge treatment and reduction,including thermal hydrolysis,fungal fermentation,and anaerobic digestion.Increasing the temperature during the treatment from 140 to 180℃ significantly improved the sludge reduction and organic release efficiencies(p<0.05,one-way analysis of variance(ANOVA)for the triplicate experiments at each temperature).After two cycles of thermal hydrolysis,the overall volatile solid reduction ratios of the sludge were 36.6%,47.7%,and 58.5%for treatment at 140,160,and 180℃,respectively,and the total organic carbon(TOC)conversion efficiency reached 28.0%,38.0%,and 45.1%,respectively.The highest concentrations of carbohydrates and proteins were obtained at 160℃ in sludge liquor,whereas the amount of humic substances significantly increased for the treatment at 180℃(p<0.05,one-way ANOVA for the triplicate experiments at each temperature)due to the Maillard reaction.Fungal fermentation of the hydrolyzed sludge liquor with Aspergillus niger converted the waste organics to valuable fiber materials.The biomass concentration of fungal hyphae reached 1.30 and 1.27 g·L^(-1) in the liquor of sludge treated at 140 and 160C,corresponding to organic conversion ratios of 24.6%and 24.0%,respectively.The fungal hyphae produced from the sludge liquor can be readily used for making papers or similar value-added fibrous products.The paper sheets made of hyphae fibers had a dense structure and strong strength with a tensile strength of 10.75 N·m·g^(-1).Combining fungal fermentation and anaerobic digestion,the overall organic utilization efficiency can exceed 75%for the liquor of sludge treated at 160℃.
基金the Key Scientific Research in Colleges and Universities of Henan Province Project(Grant No.20B560018)the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2015ZX07204-002-04).
文摘Viscous sludge bulking is a rare phenomenon in activated sludge process.The performances of nutrients removal were investigated with normal sludge and viscous bulking sludge.The results showed that when COD loading and C/N ratio were around 0.13 mg COD/(mg MLSS·d)and 7.67,the effect of viscous sludge bulking on the maximum specific oxidation rates of NH_(4)^(+)⁃N was very little,while the maximum specific oxidation rates of NO_(2)^(-)⁃N decreased from 24.69 mg/(g·h)to 1.20 mg/(g·h).Compared with normal sludge,viscous bulking sludge had bigger particle size and more extracellular polymeric substances(EPS).The mass transfer resistance in sludge flocs might be the main cause of the difference in NO-2⁃N oxidation rates.Therefore,this study demonstrates that viscous sludge bulking is beneficial to enhance simultaneous nitrification and denitrification(SND),and excessive EPS will exhibit storage function during phosphorus removal process.
基金Supported by University Students' Innovation Project of Jiangsu Province,China (166201100022 )Scientific Research Foundation of Nanjing Institute of Technology (QKJC2010011)Science and Technology Support (Industrial) Project of Jiangsu Province,China(BE2010203)
文摘[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as its influencing factors,so as to discuss the optimal conditions of sludge granulation.[Result]Through the static culture outside of IC reactor and dynamic culture in IC reactor,granular sludge appeared within a training cycle,with particle size of 1.0-1.5 mm.In IC reactor,when COD concentration of influent water was 5 000 mg /L,rising velocity was 0.9 m /h,pH was around 7,and auxiliary materials (like flocculant and active carbon) and mature granular sludge were added to the actor during the training process,the granulation process of sludge was accelerated.[Conclusion]The research could provide references for the rapid start-up of IC reactor.
基金Supported by Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_2596).
文摘This work takes sludge drying and incineration and pollutant discharge characteristics as the main line of research.With sludge dewatered by a certain sewage plant in southern Jiangsu using machinery and chemical conditioners selected as the research object,the influencing factors such as particle size,drying temperature and sludge reverse-mixing ratio in the sludge drying process were mainly explored,and the best working conditions of sludge drying were further analyzed.On this basis,in-depth research was carried out on the pollutants such as NO_(x),SO_(2),HCl,CO and other pollutants generated in the sludge incineration process by investigating the incineration temperature,sewage,the sludge moisture content and excess air coefficient.The results showed that the best conditions for sludge drying were as follows:particle size 3.5 mm,temperature 210℃and reverse-mixing ratio 25,and the cumulative drying time of the sludge 445.21 min.Through the research on the pollutant emission characteristics of sludge incineration,it was found that the incineration temperature and the moisture content of the sludge had a greater impact on the emission concentrations of NO_(x),SO_(2),HCl,and CO.Among them,the incineration temperature was the key factor that affected the generation of NO_(x),SO_(2),HCl,and CO.
文摘For the problem as high energy consumption and sludge increment during the municipal sludge management process with advanced oxidation technology of sulfate radical, the <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub></span> composite CaO reaction system was set up. Meanwhile, systematical studies had been carried out for coordinated conditioning of municipal concentrated sludge. The scientific process parameters were determined with the help of sludge capillary suction time, sewage sludge moisture content and other core indicators and the effect of traditional polyacrylamide flocculation method, Fenton method and activated persulfate method were compared. The results showed that in the neutral concentrated sludge conditioning, there were outstanding advantages for <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub> </span>composite CaO reaction system compared with Fenton, CPAM, and SO<sup>-</sup><sub style="margin-left:-7px;">4</sub><span style="white-space:normal;"></span> methods and the optimal parameters for dosage were as follows: <span style="white-space:nowrap;">Fe<sup>2+</sup>/S<sub>2</sub>O<sup>2-</sup><sub style="margin-left:-7px;">8</sub></span>: 80 - 120 mg<span style="white-space:nowrap;">·</span>g<sup>-1</sup> DS, n(Fe2+):n(SPS) = 0.8:1, CaO: 200 mg<span style="white-space:nowrap;">·</span>g<sup>-1</sup> DS. To achieve similar performance index, the dosage of Fe<sup>2+</sup> per ton for sludge could be reduced by 20%, the loss rate for iron in filtrate was 0.5%, dewatering of sludge by suction filtration was within 50 s and the moisture content for dewatering cake was 53.7%, which significantly improved the economy and practicability of SO<sup>-</sup><sub style="margin-left:-7px;">4</sub> <span style="white-space:normal;"></span>advanced oxidation technology, and the results were expected to form a useful supplement to the popularization and application of SO<sup>-</sup><sub style="margin-left:-7px;">4</sub><span style="white-space:normal;"></span> advanced oxidation technology.
文摘A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate pollution. The recovery of Cu, Ni, Zn and Cr is 94%, 91%, 90% and 95%, respectively. The ammonia was recycled by the simplified process of CaO caustic distillation. The precipitated product of Cu, Ni and Zn obtained from caustic distillation of ammonia was separated by extraction or high\|pressure hydrogen reduction in an autoclave. The qualified metal salt products were obtained through extraction. The rich chromium residue from coordinative disposal was subjected to recover Cr by hydrothermal oxidation in NaOH medium and Fe\-3O\-4 was synthesized by wet methods from the residue produced by extracting Cr. Cr was a stable chemical fixed in Fe\-3O\-4 and harmless. The recovery process has been used in a pilot plant with sludge production capacity of 2000 t/a.
文摘BACKGROUND:The process of microcrystallization,its sequel and the assessment of nucleation time is ignored.This systematic review aimed to highlight the importance of biliary microlithiasis,sludge,and crystals,and their association with gallstones,unexplained biliary pain,idiopathic pancreatitis, and sphincter of Oddi dysfunction.DATA SOURCES:Three reviewers performed a literature search of the PubMed database.Key words used were"biliary microlithiasis","biliary sludge","bile crystals","cholesterol crystallisation","bile microscopy","microcrystal formation of bile","cholesterol monohydrate crystals","nucleation time of cholesterol","gallstone formation","sphincter of Oddi dysfunction"and"idiopathic pancreatitis".Additional articles were sourced from references within the studies from the PubMed search.RESULTS:We found that biliary microcrystals account for almost all patients with gallstone disease,7%to 79%with idiopathic pancreatitis,83%with unexplained biliary pain, and 25%to 60%with altered biliary and pancreatic sphincter function.Overall,the detection of biliary microcrystals in gallstone disease has a sensitivity ranging from 55%to 87%and a specificity of 100%.In idiopathic pancreatitis,the presence of microcrystals ranges from 47%to 90%.A nucleation time less than 10 days in hepatic bile or ultra-filtered gallbladder bile has a specificity of 100%for cholesterol gallstone disease.CONCLUSIONS:Biliary crystals are associated with gallstone disease,idiopathic pancreatitis,sphincter of Oddi dysfunction, unexplained biliary pain,and post-cholecystectomy biliary pain.Pathways of cholesterol super-saturation,crystallisation, and gallstone formation have been described with scientificsupport.Bile microscopy is a useful method to detect microcrystals and the assessment of nucleation time is a good method of predicting the risk of cholesterol crystallisation.
