巷道底板泥岩泥化物固化体的力学性能

为避免煤矿巷道底板泥岩泥化物清淤抛弃产生的环境污染问题,提出了将泥岩泥化物快速固化后作为巷道路面基层材料的处理方法,并为此研制了一种高效固化剂.通过不同固化剂掺量、不同养护龄期泥岩泥化物固化体的无侧限抗压试验,对该固化体的强度与变形规律进行了研究.研究结果表明:对于掺15.0%(质量分数)固化剂的泥岩泥化物固化体,其3 d无侧限抗压强度可达28 d的85%,即该固化体具有十分明显的快硬早强特性,可以作为巷道路面的基层材料;最低固化剂掺量与龄期相关,并与龄期呈对数关系,与固化系数呈线性关系.

石灰-粉煤灰固化巷道泥岩泥化物试验研究

通过无侧限抗压强度试验和微观结构分析,研究了石灰-粉煤灰固化某巷道底板泥岩泥化物的无侧限抗压强度随龄期发展的特性以及将其作为巷道路面基层材料的可行性.试验结果表明,采用一定配比石灰-粉煤灰处理后的泥化物,其28 d的无侧限抗压强度可达到1.78 MPa.分析认为,该固化泥化物可作为巷道路面的基层材料.

某水电站坝址F_(41),F_(42)断层泥化带工程特性研究

某峡谷区水电站坝址发育有区域性断裂穿越大坝河床近岸坝基(不属于活动断裂),将其分为碎裂岩带和F41,F42断层软弱构造岩带,其中F42为泥化带,系拟建水电站最大坝高200m级坝基最软弱部位。为了提供该水电站工程设计所需的工程地质资料,在查明F41,F42断层发育几何学特征的基础上,通过勘探技术、取样室内物理力学性质试验、平洞内现场原位力学性质试验、现场原状样渗透变形试验研究其工程特性,并以试验成果为基础,提出断层泥化带主要物理力学性质及渗透性参数建议值。研究结果表明:断层泥化带工程性状差,须采取工程处理措施。可为其它工程遇到类似断层时类比参考。

Influence of Pyrolytic Biochar on Settleability and Denitrification of Activated Sludge Process

Biochar is a massively produced by-product of biomass pyrolysis to obtain renewable energy and has not been fully used. Incomplete separation of sludge and effluent and insufficient denitrification of sewage are two of main factors that influence the efficiency of activated sludge process. In this work, we proposed a new utilization of biochar and investigated the effect of biochar addition on the performance of settleability and denitrification of activated sludge. Results show that the addition of biochar can improve the settleability of activated sludge by changing the physicochemical characteristics of sludge （e.g., flocculating ability, zeta-potential, hydrophobicity, and extracellular polymeric substances constituents）. Moreover, the dissolved organic carbon released from biochar obtained at lower pyrolysis temperature can improve the nitrate removal efficiency to a certain extent.

Optimization of a digested sludge-derived mesoporous material as an efficient and stable heterogeneous catalyst for the photo-Fenton reaction

The anaerobic digestion of sludge has recently received increased interest because of the potential to transform organic matter into methane‐rich biogas. However, digested sludge, the residue produced in that process, still contains high levels of heavy metals and other harmful substances that might make traditional disposal difficult. We have devised a facile method of converting digested sludge into a mesoporous material that acts as an effective and stable heterogeneous catalyst for the photo‐Fenton reaction. A comparison of the removal of rhodamine B under different conditions showed that FAS‐1‐350, which was synthesized by mixing the digested sludge with a 1 mol/L（NH4）2Fe（SO4）2 solution followed by calcination at 350 °C, exhibited the best catalytic activity owing to its faster reaction rate and lower degree of Fe leaching. The results indicate that Fe^（2＋）‐loaded catalysts have significant potential to act as stable and efficient heterogeneous promoters for the photo‐Fenton reaction, with better performance than Fe^3＋‐loaded catalysts because the Fe（II）/Fe（III）compounds formed in the calcination process are necessary to sustain the Fenton reaction. This protocol provides an alternative, environmentally friendly method of reusing digested sludge and demonstrates an easily synthesized mesoporous material that effectively degrades azo dyes.

Study on Algae Removal by Immobilized Biosystem on Sponge

In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV 260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5 h, the removal rates of algae, microcystins and UV 260 were 90%, 94.17% and 84%, respectively.The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

Industrial wastes applications for alkalinity regulation in bauxite residue: A comprehensive review

Bauxite residue is a highly alkaline material generated from the production of alumina in which bauxite is dissolved in caustic soda.Approximately 4.4 billion tons of bauxite residues are either stockpiled or landfilled,creating environmental risks either from the generation of dust or migration of filtrates.High alkalinity is the critical factor restricting complete utilization of bauxite residues,whilst the application of alkaline regulation agents is costly and difficult to apply widely.For now,current industrial wastes,such as waste acid,ammonia nitrogen wastewater,waste gypsum and biomass,have become major problems restricting the development of the social economy.Regulation of bauxite residues alkalinity by industrial waste was proposed to achieve‘waste control by waste’with good economic and ecological benefits.This review will focus on the origin and transformation of alkalinity in bauxite residues using typical industrial waste.It will propose key research directions with an emphasis on alkaline regulation by industrial waste,whilst also providing a scientific reference point for their potential use as amendments to enhance soil formation and establish vegetation on bauxite residue disposal areas(BRDAs)following large-scale disposal.

Effect of different surfactants on removal efficiency of heavy metals in sewage sludge treated by a novel method combining bio-acidification with Fenton oxidation

The aim of this work was to investigate the effect of different surfactants on the removal efficiency of heavy metals in sewage sludge treated by a method combining bio-acidification with Fenton oxidation. Four surfactants were adopted such as anionic surfactant(sodium dodecyl benzene sulfonate, SDBS), nonionic surfactants(tween-20 and tween-60) and cationic surfactant(hexadecyl trimethyl ammonium chloride, HTAC), respectively. The indigenous sulfur-oxidizing bacteria in bio-acidification phase were enriched and cultured from fresh activated sludge obtained from a wastewater treatment plant. It is shown that different surfactants exhibited distinct effect on the removal efficiency of heavy metals from sewage sludge. The nonionic surfactants,especially tween-60, promotes the solubilization of heavy metals, while the anionic and cationic surfactants hinder the removal of heavy metals. Copper is efficiently leached. The removal efficiency of cadium is relatively lower than that of Cu due to the demand for rigorous p H value. Lead is leached with a low efficiency as the formation of low soluble Pb SO4 precipitates.

Plant Test of Industrial Waste Disposal in a Cement Kiln

Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid waste disposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results show that (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still be used in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement, and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard (GB 16297-1996).

Salt ions accumulation and distribution characteristics of pioneer plant species at a bauxite residue disposal area, China

Bauxite residue disposal areas(BRDAs)are physically degraded and hostile to plant growth.Nevertheless,natural plant colonization was observed in an abandoned BRDA in Central China.The pioneer plant species at the disposal area were identified,whilst distribution characteristics of salt ions such as Na^+,K^+,and Ca^2+in plant tissues and rhizosphere residues were investigated.The mean concentration of exchangeable Na^+in the rhizosphere soils was 19.5 cmol/kg,which suggested that these pioneer plants had relatively high salinity resistance.Sodium content varied from 0.84 cmol/kg(Digitaria sanguinalis)to 39.7 cmol/kg(Kochia scoparia),whilst K to Na ratio varied from 0.71(Myricaria bracteata)to 32.39(Digitaria sanguinalis)in the shoots,which demonstrated that the salinity tolerance mechanisms of these pioneer species differed significantly.Accumulation factors of Na^+in local plant species ranged from 0.04(D.sanguinalis)to 3.29(M.bracteata),whilst the translocation factor varied from 0.13(D.sanguinalis)to 2.92(M.bracteata).The results suggested that four pioneer plant species including K.scoparia,M.bracteate,Cynodon dactylon and D.sanguinalis could be suitable for revegetation at other disposal areas.

Selenium(Ⅵ) removal from caustic solution by synthetic Ca-Al-Cl layered double hydroxides

To extract selenium(Ⅵ)from the highly caustic leachate of copper anode slime,the Ca-Al-Cl layered double hydroxides(Ca-Al-Cl-LDHs)with a formula of Ca2 Al(OH)6 Cl·2 H2 O by three co-precipitation methods were synthesized.A plate-like morphology and hexagonal crystal structure with typical mineral phases and functional groups were identified by the FESEM,XRD,FTIR,BET and XPS analysis.The forward feeding sample exhibits the best adsorption capacity of Se(Ⅵ).The factor experiments then reveal a favorable adsorption process with low temperature,low NaOH concentration and high adsorbent dosage.Furthermore,the adsorption kinetics and isotherm parameters can be well described by the Langmuir isotherm and the pseudo-second-order models,respectively.Accordingly,the maximum adsorption amount of Se(Ⅵ)onto Ca-Al-Cl-LDHs reaches188.6 mg/g at 50 ℃.

Alkalinity stabilization behavior of bauxite residue:Ca-driving regulation characteristics of gypsum

Alkaline anions,include CO3^2–,HCO3^–,Al(OH)4^–,OH^–,continuously released from bauxite residue(BR),will cause a potential disastrous impact on surrounding environment.The composition variation of alkaline anions,alkaline phase transformation pathway,and micro-morphological transition characteristics during the gypsum addition were investigated in an attempt to understand alkalinity stabilization behavior.Results demonstrated that alkaline anions stabilization degree in leachates can reach approximately 96.29%,whilst pH and alkalinity were reduced from 10.47 to 8.15,47.39 mmol/L to 2 mmol/L,respectively.During the alkalinity stabilization,chemical regulation behavior plays significant role in driving the co-precipitation reaction among the critical alkaline anions(CO3^2–,HCO3^–,Al(OH)4^–,OH^–),with calcium carbonate(CaCO3))being the most prevalent among the transformed alkaline phases.In addition,XRD and SEM-EDX analyses of the solid phase revealed that physical immobilization behavior would also influence the stability of soluble alkali and chemical bonded alkali due to released Ca^2+from gypsum which aggregated the clay particles and stabilized them into coarse particles with a blocky structure.These findings will be beneficial for effectively regulating strong alkalinity of BR.

Long-term effects of di-octyl phthalate on the expression of immune-related genes in Tegillarca granosa

Di-octyl phthalate(DOP) is widely used as a plasticizer in the plastics industry.As a result,DOP is often found in marine water ecosystems where many species are exposed to it.Our objective was to evaluate the effect of long-term(14 d) DOP exposure(2.6,7.8,or 31.2 mg/L) on the expression of immunerelated genes in Tegillarca granosa.The expression of small heat shock protein(sHSPs) and tissue inhibitor of metalloproteinase(TIMP) were highest in clams exposed to 31.2 mg/L DOP on days 7 and 14.The relative expression of Tg-ferritin,superoxide dismutase(SOD),and metallothionein(MT) increased initially then decreased as the concentration of DOP increased.The hemoglobin of T.granosa(Tg-Hb I) exhibited two distinct expression patterns at two time points.Our results suggest that the immune response of T.granosa against DOP pollution varies depending on the dose.Additionally,we identified some immune-related genes that are promising candidates for biomarkers of DOP.

Temporal Changes in Transboundary Air Pollutants in Bottom Sediments of Lakes in East Asia

To clarify temporal changes in the transboundary pollution, we analyzed SCPs （spheroidal carbonaceous particles） in bottom sediments of lakes in China, South Korea and Japan. SCPs provide an unambiguous record of anthropogenic atmospheric pollution in bottom sediments. Recently deposited SCPs in air and unmelted snow on Mt. Fuji were also characterized. The concentrarion and characteristics of SCPs reflected the environmental and industrial history of the area. Evidence of transboundary air pollution was observed after the 1980s in Yashagaike and Kotaniike ponds in Japan, which are located on the coast of the Sea of Japan. The concentration suggests that the pollutants originated from continental Asia, particularly after the 1980s. The chemical composition of the SCPs allowed the source of emissions to be identified. Chinese SCPs were found at Yashagaike and Kotaniike ponds in Japan, and at Songiiho and Urimji lakes in Korea. The size distributions showed that small SCPs are transported over long distances. On the summit of Mr. Fuji, SCPs transported by the prevailing westerlies from China were found in addition to SCPs emitted in Japan.

Influencing factors of pyrite leaching in germ-free system

The effect of mineral particle size, pulp potential and category of oxidant on pyrite leaching was studied. The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 mm. The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3+ can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process. The leaching rate increases with the constant addition of H2O2.

From pollutant to solution of wastewater pollution: Synthesis of activated carbon from textile sludge for dye adsorption

Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5（RB5）and methylene blue（MB）onto activated carbon produced from textile sludge（TSAC）.The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650℃ under nitrogen flow.Effects of time（0–200 min）,pH（2–10）,temperature（25–60℃）,initial dye concentration（0–200 mg·L^-1）,and adsorbent dosage（0.01–0.15 g）on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H2SO4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl2.The adsorption capacity of TSAC was found to be 11.98 mg·g^-1（RB5）and 13.27 mg·g^-1（MB）,and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.

Argillization mechanics of rock from the Xing’anling Group in the Beier depression of the Hailar basin

The reservoir of the Xing'anling Group in the Beier depression of the Hailar basin is loosely cemented with many tuffaceous grains.This causes argillization and collapse of the grain framework of the reservoir sandstones.A detailed study on the characteristics of rocks and minerals was carried out through polarized microscope,X-ray diffraction,X-ray fluorescence,SEM and energy spectrum analysis.The results indicate that the reason for argillization is the abundant pyroclastic,and especially tuffaceous,grains in the reservoir.The alkaline component is relatively high in some strata.These are easily altered to montmorillonite in diagenesis.Na+montmorillonite swells strongly when exposed to water.This is the fundamental reason for the reservoir's argillization and plugging.

Biomarker Records of Phytoplankton Productivity and Community Structure Changes in the Central Yellow Sea Mud Area During the Mid-Late Holocene

The Yellow Sea （YS） environmental and ecological changes during the Holocene are driven by the interactions between the Yellow Sea Warm Current （YSWC）, the East Asian Winter Monsoon （EAWM） and the Kuroshio Current （KC）. We report marine biomarker records of brassicasterol, dinosterol and C37 alkenones in core ZY1 and core ZY2 from the South Yellow Sea （SYS） to reconstruct the spatial/temporal variations and possible mechanisms of phytoplankton primary productivity and community structure changes during the Mid-late Holocene. The contents of the corresponding biomarkers in the two cores are similar, and they also reveal broadly similar temporal trends. From 6kyr to 3kyr, the biomarker contents in the two cores were relatively low with small oscillations, followed by a distinct increase at about 3 kyr indicating productivity increases caused by a stronger EAWM. The alkenone/brassicasterol ratio （A/B） is used as a community structure proxy, which also showed higher values in both cores since 3 kyr, indicating increased haptophyte contribution to total productivity. It is proposed that the YS community structure has been mainly influenced by the YSWC, with stronger YSWC influences causing an increase in haptophyte contribution since 3 kyr. Some differences of the biomarker records between ZY2 and ZYI suggest spatial variations in response to YSWC and KC forcing. When the KC was intensified during the periods of 6-4.2kyr and 1.7-0kyr, the YSWC extended eastward, exerting more influence on core ZY1. On the other hand, when the KC weakened during 4.2-1.7 kyr, the YSWC extended westward, exerting more influence on the ZY2.

Cemented backfill technology based on phosphorous gypsum

Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.

Deterioration of Concrete by the Oxidation of Sulphide Minerals in the Aggregate

Cases of degradation of concrete associated to iron sulphides in aggregates were recently recognized in the Trois-Rivi6res area, Canada. The aggregate used to produce concrete was an anorthositic gabbro containing various proportions of pyrite, pyrrhotite, chalcopyrite and pentlandite. Quantitative microanalysis on sulphide minerals show that pyrrhotite contains small amount of Ni, Co, Cu and As substituting for Fe in the mineral structure. Considering element substitution, x value in the chemical formula （Fe~.xS） was calculated to 0.099 in the pyrrhotite studied. Petrographic examination of damaged concretes showed the presence of oxidized pyrrhotite. The observation of polished samples shows, in several cases, that the pyrite is intact while the pyrrhotite presents evident signs of oxidation. In the presence of water and oxygen, pyrrhotite oxidizes to form iron oxyhydroxides and sulphuric acid. The acid then reacts with the phases of the cement paste and provokes the formation of gypsum and ettringite. These minerals were observed by SEM-EDS （scanning electron microscope/energy dispersive x-ray spectrometer） and their precipitation causes a volume increase that creates expansion and cracking of the concrete.