Abstract:The study on the growth of chlorine resistant bacteria in water supply systems is critical for the assessment, control, and prevention of microbiological safety associated with drinking water. In this study, bulk water and biofioms in water supply system sourced from lakes and reservoirs in cold region were investigated by the detection of heterotrophic bacteria and chlorine resistant bacteria, and the biota in the biofilm were observed by scanning electron microscope. Results showed that the bacteria regrowth still existed in the bulk water even within more than 0.20 mg/L free chlorine in the distribution systems. Chlorine-resistant bacteria survived pervasively in the studied water supply system. The chlorine-resistant bacteria in post-chlorination and distributed water were less than 350 CFU/mL. The number of chlorine-resistant bacteria in the biofilm was two orders of magnitude higher than that of the bulk water in general. The chlorine resistant bacteria presented most in pre-chlorination of sand filter water and biofilm, while almost all viable bacteria in the clearwell were chlorine-resistant bacteria. Microbial morphologies in the biofilms of water supply systems were composed of cocci and rod, with the latter especially predominated in the biofilms.

Abstract:To further promote the FO performance of QSTFI membrane, polyvinyl alcohol (PVA) modified QSTFI membrane (PVA-QSTFI) has been developed. The characterization results indicated that the incorporation of a small amount of PVA onto the QSTFI membrane has significant influence on the surface hydrophilicity, pore structure, surface charge and thus FO performance. An optimum PVA loading rate of 0.5% was chosen based on the water flux and specific salt flux experiments. Using the 2.0 molL-1 NaCl as DS, deionized water as FS, the modified membrane offered a 67.08 Lm-2h-1 water flux at 25 ℃, was 12% higher than that of QSTFI membrane. Meanwhile, a specific salt flux of 0.15 gL-1 was obtained, which is 16.7% lower than QSTFI membrane.

Abstract:Pumice-supported ZnOOH catalyst, taking zinc nitrate salt as precursor substance, was prepared by incipient wetness impregnation to enhance the catalytic ozonation capacity of pumice. Catalytic ozonation of p-chloronitrobenzene (p-CNB) in aqueous solution was conducted, wherein pumice and ZnOOH-pumice were used as the catalysts. The catalyst showed significant catalytic activity in the decomposition of p-CNB in aqueous solution. It was found that the processes of ozonation/ZnOOH-pumice and ozonation/pumice could increase the removal efficiency of p-CNB by 93.4 % and 72.1 %, respectively, compared with that achieved by sole ozonation. tert-Butyl alcohol remarkably increases the removal efficiency of catalytic p-CNB ozonation, which suggests that p-CNB degradation follows the mechanism of hydroxyl radical (·OH) oxidation. Catalytic ozone decomposition and ·OH captured show that ZnOOH-pumice catalyzed ozone generates the highest ·OH concentrations under the present experimental conditions compared with that obtained from the ozone/pumice and ozone-alone systems. Different water qualities show a very strong influence on the catalytic ozonation of p-CNB. From a practical point of view, ZnOOH-pumice shows promise for use in water treatment because it retains its catalytic activity for up to ten successive cycles and the residual ion content was minimal after catalytic ozonation.

Abstract:In order to investigate the leachability of chromium from chromite ore processing residue (COPR) during the detoxification process, the leaching behavior of total chromium, hexavalent chromium and other main metal elements in the COPR samples under different pH were evaluated. The chemical compositions and mineral phases of COPR were analyzed by X-ray fluorescence spectrometry (XRF), X-ray power diffraction (XRPD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results indicated that Cr6+ exist as the major fraction in both leachates of the sulfuric acid/nitric acid extraction and the toxicity characteristic leaching procedure (TCLP) extraction. Strong alkaline properties of COPR and its large alkaline buffer capacity were the two main factors affected the detoxification process using reduction method. Therefore, the chosen of an optimum pH is the key process to enhance the leachability of hexavalent chromium from COPR. High leachability of hexavalent chromium from COPR can be achieved under pH8.0, with a relatively low operational cost.

Abstract:To ensure the aquatic environment security and promote the sustainable development of nanotechnology, the interactions between nanomaterials and environmental nanopollutants (humic acid and sodium dodecyl benzene sulfonate) were investigated. The effects of the surrounding solution chemistry (pH and ionic strength) on the interaction were discussed. The results suggested that the interaction between nanomaterials and environmental nanopollutants could inhibit the aggregation of nanoparticles, and then enhance their mobility in aquatic environments. The interaction was affected by pH and ionic strength. The absorbed content of humic acid and SDBS on the surface of TiO₂ nanoparticles increased near the pHpzc (point zero of charge) due to the charge screening effect. It also increased with the increasing ionic strength due to the compression of the electric double layer. The interaction mechanisms between nanomaterials and environmental nanopollutants were discussed. The interaction process could be divided into three processes, including aggregation, approaching and strong interaction. The differences of interaction mechanisms between humic acid and SDBS were also discussed.

Abstract:A novel modified Page Rank algorithm for pipe renewal (MPR-Pipe) is presented to realize selection sort and provide Page Rank values of static and dynamic attributions of junctions and pipes in water distribution systems. The measurement of pipe renewal significance, well defined on the grounds of economic flow and unit hydraulic gradient, can be taken as the criterion for the selection sort of pipe renewal. Theoretical calculations confirm the high efficiency of the algorithm, and engineering application cases indicate the effectiveness and feasibility of the renewal plan based on MPR-Pipe algorithm.

Abstract:In order to investigate the anoxic biodegradability and degradation pathway of three typical organic pollutants (quinoline, pyridine and catechol) in coal gasification wastewater, the acclimated anoxic activated sludge used as seeded sludge with NO₃--N as electron acceptor, and the anoxic degradation intermediates of the three pollutants were determined by UV-Vis and GC/MS analysis. Results showed that the inhibitory and toxic effects of the three compounds strengthened with the increase of the initial concentration. The residual concentration with the of its initial concentration 48 h anoxic treatment. The anoxic degradation rate constants of the three pollutants in descending order were pyridine, catechol and quinoline. The pollutants were partly converted into intermediates which were more refractory than the original compounds, instead of being mineralized to CO₂ and H₂O. The anoxic biodegradability of these pollutants enhanced with the addition of glucose as co-substrate. The co-metabolism effects were more significant when the pollutants were more refractory. The degradation of quinoline and pyridine initiated with the hydroxylation reaction. The possible degradation pathways were proposed based on the intermediates analysis. QSBR studies of the above three compounds showed that biodegradation rate constant (K_s) was significantly correlated with molecular connectivity indices ¹X^v as well as highest occupied molecular orbital EHOMO.

Abstract:To control the production cost of the particle electrodes, a novel particle electrode was prepared using the steel slag, which has certain magnetism and could be applied for the dyeing wastewater treatment. The steel slag particle electrodes, with a saturation magnetic induction of 1.638 6 A·m²/kg, were characterized by SEM and VSM. Moreover, the prepared magnetic particle electrodes were utilized in a three-dimensional electrochemical oxidation system for simulative printing/dyeing wastewater treatment. Experimental results showed that the optimal parameters were: initial concentration of the solution of 5 mg/L, initial pH value of 4, applied voltage of 5 V, and concentration of the supporting electrolyte of 0.15 mol/L.

Abstract:In order to investigate the microwave pyrolysis characteristics of sewage sludge under different pyrolysis conditions, effect of microwave power, sewage sludge moisture content and microwave absorbing material content on the sewage sludge pyrolysis process and the pyrolysis residues was investigated. The microwave pyrolysis conditions of sewage sludge were optimized using response surface methodology and the components of pyrolysis residue were analyzed. The predicted highest pyrolysis efficiency of sewage sludge obtained from the response surface methodology was 77.4% when microwave power was 1 880 W, sludge moisture content was 79.7% and microwave absorbing materials content was 0.48 g. For comparison, the actual measurement one was 77.5%.Ash and fixed carbon accounted for a large proportion of the pyrolysis residues and the major inorganic components were SiO₂, Al₂O₃, Fe₂O₃ and CaO, etc.

Abstract:The concept of material transportation radius for straw-energy engineering, proposed in line with the regional characteristics and project types, is of great significance in promoting engineering economic efficiency and ecological environmental protection. Taking the concept as the core, straw energy conversion density and the evaluation model for engineering economy and environmental efficiency have been put forward, with the evaluation indicators including economic units and the reduction potentials in the emission of greenhouse gases and PM 2.5. An economic and environmental evaluation of the straw transportation radius in Harbin region has fully demonstrated that Harbin, the most advantageous region in Heilongjiang Province in developing straw-energy engineering, embraces the economically optimized straw transportation radiuses of 37, 5,2 km, and 4 km respectively for the development of straw-gasification, -ethanol, -based heat and power cogeneration and -briquetting production projects. Meanwhile, in view of environmental benefits, the descending order of the 4 types of energy engineering are straw-gasification, -ethanol, -based heat and power cogeneration and -briquetting production projects.

Abstract:In order to obtain the optimum emergency disposal technology scheme for the pollution of surface drinking water source, a threat-evaluation index system with 12 indicators was established based on analytic hierarchy process (AHP). Meanwhile, the technique evaluation system containing 19 indices was also developed, with different threat-levels corresponded to different weights of each evaluation indicator. The scientificity of the multiple evaluation systems has been evaluated using a sudden aniline pollution accident occurred in Shanxi. Experimental results showed that the evaluation system can assess the disposal technology schemes accurately once the accident occurred, and will provide technical support for emergency experts.

Abstract:In order to systematically evaluate the activities of the noble metal catalysts for simultaneous removal of soot and NO_x and the corresponding effect of sulfur and water, a series of noble metal catalysts (Ru／ZrO₂, Ag／ZrO₂, Rh／ZrO₂, Pd／ZrO₂, Pt／ZrO₂, Ir／ZrO₂, Au／ZrO₂) were prepared by iso-volumetric impregnation method firstly. Then the activities of the noble metal catalysts for simultaneous removal of soot and NO_x were measured under oxygen-rich condition, and the effect of SO₂ and H₂O on the performances of those catalysts were also studied. Experimental results showed that noble metal can improve the activities of simultaneous removal of soot and NO_x significantly. Compared with the other catalysts, Ru／ZrO₂, Ag／ZrO_2and Pd／ZrO₂ have higher catalytic activity. The existence of SO₂ and H₂O promoted Ir／ZrO₂ catalystal removal of soot and NO_x simultaneously, promoted Pt／ZrO₂ catalyze for soot oxidation, Ru／ZrO₂ for NO_x reduction and inhibited the catalytic activities of other noble metals.

Abstract:To study the VOCs removal in cooking oil fume, the degradation of butyraldehyde as the target pollutant by Mn2+ catalytic ozonation was studied, the reaction conditions that affect the removal efficiency of butyraldehyde including the presence or absence of Mn2+, pH, catalyst concentration, the initial concentration of butyraldehyde, \[O₃\]/\[butyraldehyde\] concentration ratio, temperature were investigated . The results showed that: the addition of Mn2+ can significantly improve the removal efficiency of butyraldehyde, and the removal efficiency improved with the decrease of the concentration of butyraldehyde and the increase of \[O₃\]/\[butyraldehyde\] concentration ratio. The degradation rate firstly increased then decreased with the increase of the concentration of Mn2+ and temperature, reaching the optimization when at 1 mmol/L and 30 ℃, respectively. The optimal pH existed, which is 5.When catalyst concentration was 1 mmol/L, pH =5,the initial concentration of the butyraldehyde 200 mL/m³,\[O₃\]/\[butyraldehyde\]= 0.2, under the room temperature, the removal rate of butyraldehyde is 94.67%, mineralization is 91.8%.

Abstract:In order to solve the problem of multi-borehole ground thermal resistance calculation concerning thermal interference in the national standard, a numerical method for vertical ground heat exchanger is presented in this paper. And ground thermal resistance distributions of different borehole configurations and different separation space between two neighboring boreholes were studied through a case study. The results show that for regular rectangular-array borehole configuration, the ground thermal resistance in the central position is largest, also, the more the configuration reaches a square, the smaller the separation space is, the larger the total subsurface thermal resistance is; while for irregular rectangular-array borehole configuration, the position where largest subsurface thermal resistance is located will exist at a new negligible offset. The research output can provide theoretical reference for the design of vertical ground heat exchanger.

Abstract:Tube-in-tube type adsorber was designed and proposed based on analyzing various influencing factors as well as heat effect in the process of adsorption and desorption. And then its mathematical model was established and solved. Finally, the adsorbing capacity and desorption rate of adsorber were simulated at the condition of different temperatures of water bubbled into it. Results showed that tube-in-tube type adsorber could enhance carbon dioxide adsorption and capture from flue gas, which are helpful for potential engineering application.

Abstract:The feasibility of CANON granular sludge for efficient nitrogen removal from domestic wastewater was investigated in SBR. Firstly, CANON granular sludge was started by stirring under high ammonia concentration conditions, then granular sludge was increasingly added to improve the performance of nitrogen removal. Finally, the feasibility for domestic wastewater treating was investigated. The results show that CANON granular sludge could start-up within 40 days, the size of granular sludge reached 760 μm and the total nitrogen removal rate reached 1.01 kg/(m³d) within 126 days. A linear relationship between the ratio of polysaccharide and protein and the particle size growth was found. The total nitrogen removal rate increased rapidly to 3.22 kg/(m³d) within 77 days by adding granular sludge. Simultaneous removal of nitrogen and COD proved that the CANON granular sludge could be applied as an efficient approach for treating domestic wastewater.

Abstract:Simultaneously partial nitrification, anammox and denitrification (SNAD) process was used for treating domestic sewage in a membrane bioreactor (MBR). Domestic sewage was gradually pumped into the system, removal trend of the pollutants were evaluated via the changing of operational HRT and air flow. The nitrogen removal pathway was analyzed via the mass balance analyze studying, and microbial characteristics via clone-sequencing detection. Results suggested that a simultaneous removal of C, N and SS was achieved in the system, with the nitrogen removal rate to 0.65 kg/(m³d), effluent ammonia below 10 mg/L; COD removal efficiency to 87%, effluent COD below 50 mg/L; turbidity removal to 99%, effluent turbidity below 1 NTU, and SS below 10 mg/L, which met the demand of the first grade A standards of Urban Sewage Disposal Plant Contamination Integrated Discharge Standard (GB18918-2002). Denitrification contributed to 12% nitrogen removal while (completely autotrophic nitrogen removal over nitrite, CANON) contributed to 88%, and AOB, anammox and denitrifiers coexisted in the reactor.

Abstract:A SWMM (Storm water management model)-based method for the adjustment of rain-off model parameters is proposed to realize the equivalent design conditions in pipe network design calibration with hydraulic model. The method proceeds from the basic principle of Rational Method, and takes the assumption of runoff curves with time as the basis. By simulating the runoff catchment through constant rainfall pattern, the principle of equivalent can be judged by whether the features of the simulated runoff curves matched those of the assumption with Rational Method. Case study has verified the feasibility of the proposed method. Meanwhile, to simplify the manual operation in parameters adjustment, an improved particle swarm optimization (PSO) has been put forward to complete the process automatically.

Abstract:This work was to investigate the formation potential of trihalomethane(THM) and trichloronitromethane (TCNM) for algae extracellular organic matter (EOM) and intracellular organic matter (IOM) in different algae growth stages and chlorine dosages, and the effects on the production of THMs and TCNM during chlorination were further studied. Results showed that EOM and IOM had high concentrations of TOC and DON, while low organic component of aromatic structure and unsaturated double bonds. The yields of TCNM from chlorinated EOM increased from high biomass logarithmic phase to declinephase.However, TCNM of IOM followed an increasing and then decreasing pattern with the extent of growth days. The pattern of THMsFP was similar to TCNMFP, but the concentrations of THMs were much higher than TCNM. TCNM increased with chlorine dosages during EOM chlorinated, for IOM, however, the concentration of TCNM firstly increased and then decreased. The maximum TCNM yield of IOM appeared on chlorine dosage of 30 mg/L.TCM was the dominant fraction of THMs. In stationary phase, THMs produced from EOM and IOM gradually increased with chlorine dosage from 20 to 30 mg/L, but increased significantly at more than 30 mg/L.

Abstract:To improve the dewaterability of municipal sludge, the Acidithiobacillus ferrooxidans (At·fXJF8) cultivated in a laboratory-scale plug flow reactor (68 L) were used, which had efficient biomineralization and biological acidification. Chemical parameters of pH, specific resistance, suction filter mud cake moisture content of the municipal sludge was determined pre-and after dehydration etc. The optimum operation parameters of the reactor was: SRT 3.7 d, Fe(Ⅱ) dosage 2.11 g·L-1, reflux ratio 80%. Experiment result showed that the pH of the sludge decreased from 7.22 (stat-up stage) to 2.95 (steady stage) after the dewatering, and the specific resistance to filtration (SRF) of sludge decreased from initial (4.2±0.59)×10¹² m·kg-1 to the final (0.55±0.11)×10¹² m·kg-1. Ferrous oxidation rate kept above 96% in the whole running process. At the condition of 0.05 MPa pressure from the suction filtration, water content of the sludge decreased from 80% to 68%. This paper developed a new method for the sewage sludge dewaterability with the bio-acidification and ferrous oxidation by At· fXJF8.

Abstract:To lower dust concentration at fully mechanized caving faces, master spatial distribution rules of dust in various operation processes, and effectively direct dust control, the thesis, on the basis of gas-solid two-phase flow theory, carried out the numerical simulations with Fluent software to trail the dust distribution rules of coal cutting, support moving, sub-level caving, and transshipping at fully mechanized caving faces in single and multiple processes, and the results of which were made comparison with the site data. The findings were as follows. Coal-cutting dust spreads not only along the chute of shearer, but to footway, thus dust control near the drum and water curtain for dust reduction are necessary. Dust concentration of footway is higher than that of chute when moving supports, therefore, mist spray between supports should be equipped both in footway and chute. Considering the higher dust concentration of sub-level caving at the footway, dust separation should be done in the drawing opening. Higher air velocity at partial area of transpersite and a widespread effect of dust require the measures like sealing be adopted. In addition, full-section spraying devices should be installed between processes of sub-level caving and coal cutting.

Abstract:In order to understand the temperature characteristic of fire whirls in the vertical shaft, numerical simulations were carried out to study the centerline plume temperature of fire whirls in the vertical shaft. The numerical simulation results of centerline plume temperature were verified by using experimental data. It was found that plume temperature of fire whirls in the vertical shaft can be approximately divided into three regions which were stretched in the vertical direction based on the theory proposed by McCaffrey. The height values of different regions and formula coefficients were obtained, which are suitable for centerline plume temperature of fire whirls in the vertical shaft.

Abstract:To solve matching problem between the sun′s available heat and heating demand in the design of passive solar building. The indicator of “solar passive heating thermal coefficient”(SPHTC) was proposed based on the principle of unsteady heat transfer. Based on case study of Lhasa and Beijing, the contribution of solar radiation for heating energy consumption was analyzed by calculating SPHTC. The control strategy for intermittent active and passive combined solar heating system was proposed, and the feasibility of such system in regions with rich solar energy was evaluated .

Abstract:Seismic performance of the multi-ribbed composite wall structure with large space at the bottom, combined with the new oblique frame-grid used in multi-ribbed structure was studied in this paper. The pseudo-static experiment of two 1/2-scale multi-ribbed composite wall supported on frame shear-wall structure was conducted. Under the low reversed cyclic loading, the failure process and force transfer mechanism of the oblique and orthogonal frame-gird specimens was analyzed. The hysteretic characteristic of inter-story displacement, steel load-strain curves of the members, residual deformation ratio of the specimen was discussed. The results show that the structure have good seismic performance. The unique oblique frame-grid design can improve the overall ductility, deformation, collapse-resistant capacity and reparability.

Abstract:Flexural behavior of EB-FRP (externally bonded FRP) and HB-FRP (hybrid bonded FRP) strengthened RC beams is studied in this paper. Three beams test and finite element analysis was conducted. Basis on appropriate material model, blunt crack model, modelling of steel and FRP and their bond behavior, numerical finite element model is verified by comparing with model test results. The results show that failure mode of EB-FRP strengthened beams is plate end interfacial deboning. Failure mode of HB-FRP strengthened beams is shear failure. Compared with the beams without FRP strengthening, the flexural capacity increased by 20% for HB-FRP than EB-FRP. The FRP stress is about FRP strength for HB-FRP and steel fasters effectively prevent FRP deboning.