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《化工环保》2018,(6)
采用CaCl_2和纳米SiO_2-聚硅酸铝铁复合混凝剂对含氟废水进行两步除氟。实验结果表明:ρ(F-)为420.0 mg/L、pH为8.5的含氟废水经CaCl_2处理后ρ(F-)降至26.5 mg/L;在二级除氟pH为11.5、复合混凝剂加入量(复合混凝剂与废水体积比)为0.50%的最佳条件下处理60 min后废水中ρ(F-)降至5.7 mg/L,而采用聚合氯化铝(PAC)进行二级除氟时,ρ(F-)可降至8.7 mg/L,表明复合混凝剂比PAC的除氟效果更佳。复合混凝剂中自由离子和单体羟基配合物形态Al和Fe的含量相对较高,分别占76.5%和92.5%,而低聚合度的多核羟基配合物及高聚物形态Al和Fe的含量相对较低。 相似文献
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混凝—催化氧化法处理丁苯橡胶生产废水 总被引:3,自引:0,他引:3
以聚合氯化铝(PAC)、阴离子聚丙烯酰胺(PAM)为混凝剂,以H2O2-O3为氧化剂,采用混凝-催化氧化法处理对丁苯橡胶生产废水。考察了混凝剂种类及其加入量、废水pH对混凝处理效果的影响,氧化剂及其加入量、反应时间和废水pH对COD去除率的影响。实验得出的最佳工艺条件:混凝实验,废水pH为7、PAC和PAM加入量为400mg/L和4mg/L;催化氧化实验,废水pH为7~8、H2O2加入量为200mg/L、H2O2与O3的质量比为0.5。处理后,废水COD从860mg/L降至145mg/L,COD去除率达83.1%,出水水质达到国家二级排放标准。 相似文献
4.
采用CaCl2和纳米SiO2-聚硅酸铝铁复合混凝剂对含氟废水进行两步除氟。实验结果表明:ρ( F–)为 420.0 mg/L、pH为8.5的含氟废水经CaCl2处理后ρ( F–)降至26.5 mg/L;在二级除氟pH为11.5、复合混凝剂加入量(复合混凝剂与废水体积比)为0.50%的最佳条件下处理60 min后废水中ρ( F–)降至5.7 mg/L,而采用聚合氯化铝(PAC)进行二级除氟时,ρ( F–)可降至8.7 mg/L,表明复合混凝剂比PAC的除氟效果更佳。复合混凝剂中自由离子和单体羟基配合物形态Al和Fe的含量相对较高,分别占76.5%和92.5%,而低聚合度的多核羟基配合物及高聚物形态Al和Fe的含量相对较低。 相似文献
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采用硅藻土对聚合硫酸铁(PFS)、聚合氯化铝(PAC)的混凝能力进行强化,并用于线路板含络合铜废水中铜的去除。考察了硅藻土加入量、混凝剂加入量、pH、快速搅拌速率和沉淀时间等因素对除铜效果的影响,并与目前常用的硫化钠破络方法进行了对比。实验结果表明:硅藻土强化混凝的除铜效果明显好于单独投加PAC或PFS;PFS-硅藻土除铜效果好于PAC-硅藻土;在pH为8.0~9.0、硅藻土加入量为120 mg/L、PFS加入量为60 mg/L、快速搅拌速率为250 r/min的条件下,沉淀40 min后可使出水铜质量浓度低于0.30 mg/L,比传统破络工艺出水水质更稳定,成本更低。 相似文献
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采用农药三唑醇生产过程中产生的含铝酸性废水为原料,合成了聚合硫酸铝(PAS)液体混凝剂,并用于厂区污水站好氧池出水的混凝处理。考察了碱化剂用量、聚合温度、聚合时间等合成条件及PAS加入量、混凝pH等混凝条件对混凝效果的影响,并比较了PAS与商售聚合氯化铝(PAC)的混凝效果。实验结果表明:在n(碱化剂)∶n(硫酸铝)为2.1∶1、聚合温度为80℃、聚合时间为60 min的条件下,所得PAS液体混凝剂产品的w(Al2O3)为7.8%~9.0%,盐基度为45%~60%,pH为3.5~4.0,产量为0.75 t/t(以废水计);在PAS加入量为2.0 m L/L、混凝pH为10.0时,COD和SS的去除率则分别达到14.6%和83.0%;该PAS可替代厂区常规使用的商售PAC,日节约废水处理成本5 922元。 相似文献
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采用混凝-Fenton试剂氧化或混凝-臭氧氧化两种氧化技术预处理上海某医药集团原料药废水。实验结果表明:采用聚合氯化铝(PAC)和聚丙烯酰胺(PAM)复合混凝处理该废水,在混凝pH为9.5、混凝时间1h、PAC和PAM加入量分别为600mg/L和12mg/L时,COD的去除率可达23%;混凝后废水再分别用臭氧氧化和Fenton试剂氧化处理,臭氧氧化明显比Fenton试剂氧化经济有效,在臭氧氧化pH为10、臭氧加入量为15g/L、臭氧氧化时间为1h的条件下,废水COD去除率为27.8%,废水BOD5/COD明显提高,为后续生化处理提供了良好的条件。 相似文献
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George Ice Liz Dent Josh Robben Pete Cafferata Jeff Light Brian Sugden Terry Cundy 《Water, Air, & Soil Pollution: Focus》2004,4(1):143-169
The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region. 相似文献
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Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification 总被引:2,自引:0,他引:2
Kopáček Jiří StuchlÍk Evžen Veselý Josef Schaumburg Jochen Anderson Iris C. Fott Jan Hejzlar Josef Vrba Jaroslav 《Water, Air, & Soil Pollution: Focus》2002,2(2):91-114
Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m-2 yr-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO4
-2, NO3
-, and NH4
+ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO4
-2 and NO3
- decreased (average ± standard deviation) by 22±7 and 12±7 mol L-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca2+ + Mg2+ (17±7 mol L-1) and H+ (4±6 mol L-1), and an increase in HCO3
-(10±10 mol L-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L-1), Ca2+ + Mg2+ (9±6 mol L-1), and H+ (6±5 mol L-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO4
-2 and NO3
- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance. 相似文献
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Stuchlík E. Appleby P. Bitušík P. Curtis C. Fott J. Kopáček J. Pražáková M. Rose N. Strunecký O. Wright R. F. 《Water, Air, & Soil Pollution: Focus》2002,2(2):127-138
Starolesnianske pleso is a small and shallow acid lake in the High Tatra Mountains, situated at 2000 m above sea level, on granitic bedrock, with sparse and thin soil cover. When detailed measurements began in the 1980s Starolesnianske pleso had pH below 5 and only one species of cladoceran zooplankton, the ubiquitous Chydorus sphaericusPalaeolimnological investigations show changes in cladoceran zooplankton and chironomid zoobenthic assemblages since about 1920 and a major change in 1970–1980. The dynamic acidification model MAGIC was used to reconstruct changes in water chemistry over the past 150 years. The results from MAGIC agree well with the sediment record; pH levels gradually decreased from 6.5 in the mid-1800s to about 5.6 in 1920 (first response in biota) to below 5.0 by 1970, and concentrations of inorganic aluminium rose dramatically beginning about 1960. In the 1990s the lake water chemistry showed clear signs of reversal in acidification brought about by a major decline in S deposition. 相似文献
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The removal of a mixture of heavy (toxic) metal cations (copper, nickeland zinc) from liquid effluents was investigated in this study at pilotscale, using counter-current contact mode. The innovative processinvolved the abstraction of metal ions onto fungal biosorbents, followedby the application of flotation for the subsequent solid/liquid separationof biomass particles. The ability of microorganisms to remove metal ionsfrom aqueous solutions is a well-known phenomenon. Nevertheless,engineering considerations are very important in decisions, concerningthe commercial future of biosorption and practical solutions are neededfor certain problems, such as the efficient post-separation ofmetal-loaded biomass. The two processes (flotation and biosorption) caneffectively operate in combination, in what it was termed biosorptiveflotation process. The sorbents may be recycled, after appropriate elutionof metals, as well as the treated (clean) water. 相似文献
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Mining activity in SE of Spain, in the west Mediterranean coast, originated more than two millenniums ago. It has generated huge areas affected by heavy metals contamination, especially of lead, which is possibly one of the most important. Investigations related to the selection of autochthonous plant taxa from a typical Spanish Mediterranean area, useful for phytoextraction and phytostabilization purposes in these polluted areas are shown. Under these edaphoclimatic conditions 12 interesting species were considered, from them six taxa were chosen for further studies. Some plant species have been proposed either for phytoextraction or phytostabilization purposes. Recommendations for further research have been discussed. 相似文献
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The concentrations of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb andZn) and arsenic (As) were surveyed and the metal pools estimatedin soils in Stockholm Municipality. The sampling sites were distributed all over the entire municipality with a higher sampling density in the city centre. Soils were sampled to a maximum depth of 25 to 60 cm. Soil texture, total-C content, electrical conductivity and pH were analysed. Heavy metal concentrations were determined after wet digestion with boiling7 M HNO3.The results showed a wide range in heavy metal concentrations, as well as in other soil properties. The city centre soils constituted a rather homogeneous group whereas outside this areano geographical zones could be distinguished. These soils were grouped based on present land use, i.e. undisturbed soils, public parks, wasteland (mainly former industrial areas), and roadside soils. The city centre and wasteland soils generally hadenhanced heavy metal concentrations to at least 30 cm depth compared to park soils outside the city centre and rural (arable)soils in the region, which were used to estimate background levels. For example, the mean Hg concentration was 0.9 (max 3.3)mg kg-1 soil at 0–5 cm and 1.0 (max 2.9) at 30 cm depth in the city centre soils, while the background level was 0,04 mg kg-1. Corresponding values for Pb were 104 (max 444) and135 (max 339) mg kg-1, at 0–5 and 30 cm, respectively, while the background level was 17 mg kg-1.The average soil pools (0–30 cm depth) of Cu, Pb and Zn were 21,38 and 58 g m-2 respectively, which for Pb was 3–4 timeshigher and for Cu and Zn 1.5–2 times higher than the backgroundlevel. The total amount of accumulated metals (down to 30 cm)in the city centre soils (4.5*10 6 m2 public gardens and green areas) was estimated at 80, 1.1, 120 and 40 t for Cu, Hg, Pb and Zn, respectively. The study showed (1) thatfrom a metal contamination point of view, more homogeneous soilgroups were obtained based on present land use than on geographicdistance to the city centre, (2) the importance of establishing a background level in order to quantify the degree of contamination, and (3) soil samples has to be taken below the surface layer (and deeper than 30 cm) in order to quantify theaccumulated metal pools in urban soils. 相似文献
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Elisângela Corradini Syed H. Imam José A. M. Agnelli Luiz H. C. Mattoso 《Journal of Polymers and the Environment》2009,17(1):1-9
Coconut, sisal and jute fibers were added as reinforcement materials in a biodegradable polymer matrix comprised of starch/gluten/glycerol.
The content of fibers used in the composites varied from 5% to 30% by weight of the total polymers (starch and gluten). Materials
were processed in a Haake torque rheometer (120 °C, 50 rpm) for 6 min. The mixtures obtained were molded by heat compression
and further characterized. Addition of lignocellulosic fibers in the matrix decreased the water absorption at equilibrium.
The diffusion coefficient decreased sharply around 5% fiber concentration, and further fiber additions caused only small variations.
The thermogravimetric (TG) analysis revealed improved thermal stability of matrix upon addition of fibers. The Young’s modulus
and ultimate tensile strength increased with fiber content in the matrix. The storage modulus increased with increasing fiber
content, whereas tanδ curves decreased, confirming the reinforcing effect of the fibers. Morphology of the composites analyzed
under the scanning electron microscope (SEM) exhibited good interfacial adhesion between the matrix and the added fibers.
Matrix degraded rapidly in compost, and addition of increased amounts of coconut fiber in the matrix caused a slowdown the
biodegradability of the matrix.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may be
suitable. 相似文献
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Roland Geyer Hans H. Richnow Dietmar Schlosser 《Water, Air, & Soil Pollution: Focus》2002,2(3):153-159
In experiments employing the lignocellulose-decaying basidiomycetes Trametes versicolor and Stropharia rugosoannulata degrading uniformly14C-labelled 2,4-dichlorophenol and pentachlorophenol, acombination of size exclusion chromatography (SEC),fractionation, and -scintillation counting wasapplied to quantify polymerisation products formed duringchlorophenol degradation. Time-dependent mass balances weregenerated by analysis of 14C in polymerisation products,CO2, as well as monomer non-polar and polar metabolites.Approximately 30% of the chlorophenols were found to bepolymerised. A major fraction of the polymerised productscorresponded to a molecular weight range from 0.24 – 40 kDa.Only a minor fraction could be attributed to a molecularweight >40 kDa. This method proved to be useful inquantification of polymerisation products and kinetics of thepolymerisation processes, whereas UV/Vis detection ofpolymerisation products separated by SEC led to false positiveresults. The SEC-14C method could also be applied forother complex processes where polymerisation ordepolymerisation occurs (humification, degradation oflignocellulose, formation of bound residues from xenobioticssuch as polycyclic aromatic hydrocarbons or 2,4,6-trinitrotoluene) and where spectrophotometric determinationsare difficult or impossible. 相似文献
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Tim Chatterton Stephen Dorling Andrew Lovett Michael Stephenson 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):173-187
This study uses a combination of data from U.K. monitoringstations and from modelling undertaken with the U.K.Meteorological Office's NAME Model to investigate therelative influences of primary and secondary particulateson total PM10 levels at sites in the United Kingdom. Co-located PM10 and sulphate aerosol measurementsindicate that sulphate has a disproportionately largeinfluence on the variation of PM10 levels incomparison to its contribution to their total mass.Comparisons of measured PM10 at urban centre, roadsideand rural sites suggest that local primary sources havevery little influence on daily mean levels. NAME has beenused to model both primary particles and sulphate aerosolfrom sources across the whole of Europe. The discrepanciesbetween modelled and observed PM10 suggest that coarseparticles, such as windblown dust and resuspended roaddust,may comprise a very large, if not dominant, proportion ofobserved PM10 levels. The apparently minor role ofprimary particles (especially locally-sourced ones) raisesa number of issues regarding the suitability of current U.K.and European legislation to addressing the particle problem. 相似文献
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Armelle Braud Karine Jézéquel Emilie Vieille Adrien Tritter Thierry Lebeau 《Water, Air, & Soil Pollution: Focus》2006,6(3-4):261-279
Partly because of the low bioavailability of metals, the soil cleaning-up using phytoremediation is usually time-consuming.
In order to enhance the amount of metals at the plant's disposal, the soil bioaugmentation coupled together with phytoextraction
is an emerging technology. In this preliminary work, two agricultural soils which mainly differed in their Cr, Hg and Pb contents
(LC, low-contaminated soil; HC, high-contaminated soil) were bioaugmented in laboratory conditions by either bacterial (Bacillus subtilis, Pseudomonas aeruginosa, Pseudomonas fluorescens or Ralstonia metallidurans) or fungal inocula (Aspergillus niger or Penicillium simplicissimum) and incubated during three weeks. The LC soil pots bioaugmented with A. niger and P. aeruginosa contained higher concentrations of Cr (0.08 and 0.25 mg.kg−1 dw soil) and Pb (0.25 and 0.3 mg.kg−1 dw soil) in the exchangeable fraction F1 (extraction with MgCl2) by comparison with the non-bioaugmented soil where neither Cr nor Pb was detected. Conversely, immobilization of Cr and
Pb in the soil were observed with the other microorganisms. The soil bioaugmentation not only modified the metal speciation
for the most easily extractable fractions but also modified the distribution of metals in the other fractions, to a lesser
extent nevertheless. The difference in microbial concentrations between the bioaugmented or not HC soils reached up to 1.8
log units. Thus the microorganisms that we chose for the soil bioaugmentation were competitive towards the indigenous microflora.
The PCA analysis showed close positive relationships between the microorganisms which potentially produced siderophores in
the soil and the amount of Cr and Pb in the fraction F1. 相似文献