MBBR两种填料对养猪废水脱氮除磷效果对比

为了探讨移动床生物膜反应器中不同填料对废水脱氮除磷效果的影响,采用碳纤维球和聚乙烯塑料两种不同悬浮填料进行对比试验。在不同运行条件下,分别测定氨氮、总氮、总磷、COD等指标,对比挂膜和脱氮除磷效果。结果表明,碳纤维球填料挂膜速度快,在不同运行条件下均比聚乙烯塑料填料对COD、NH4+-N、TN、TP等的去除效果好,去除率分别可达91.2%、98.0%、77.5%、68.1%。这说明比表面积大、孔隙率高的填料挂膜更快,挂膜量更多,更有利于实现同时生物脱氮除磷。     

聚硅硫酸铁絮凝剂去除市政污水磷的研究

将自制复合絮凝剂聚硅硫酸铁(PFSS i)用于市政污水除磷,考察了影响PFSS i除磷效果的一些因素,确定了PFSS i复合絮凝剂除磷的优化配比和用量。在优化条件下,对模拟污水中磷的去除率为96.7%,浊度去除率为92%;对实际污水中磷的去除率为82.3%,浊度去除率为96.5%。结果表明该复合絮凝剂有良好的除磷、除浊性能。     

New data of electron-beam treatment of municipal wastewater in the aerosol flow

New data on electron-beam treatment of municipal wastewater in the aerosol flow are presented. The effects of electron irradiation on various parameters (color, COD, BOD₅, total number of microbes, odor, content of pollutants and so on) of municipal wastewater are considered. The special attention is paid to the radiation-induced decomposition of synthetic surfactants.     

Electrochemical removal and recovery of phosphorus from wastewater using cathodic membrane filtration reactor

Removal and recovery of phosphorus (P) from wastewater is of great importance to addressing the challenges of eutrophication and phosphorus shortage. The P removal and recovery performance of conventional electrochemical precipitation approach was constrained by the limited mass transfer rate. Herein, a cathodic membrane filtration (CMF) reactor was developed using Ti/SnO₂-Sb anode and titanium mesh cathodic membrane module to achieve efficient removal and recovery of P in wastewater. Compared with the flow-by mode, the CMF system in the flow-through mode exhibited excellent P removal performance due to the markedly enhanced mass transfer. At the current density of 4 A/m², membrane flux of 16.6 L m^?2 h^?1, and Ca/P molar ratio of 1.67, the removal efficiency of P was 96.2% and the energy consumption was only 45.7 kWh/kg P. The local high pH of cathode surface played a vital role in P removal, which substantially accelerated the nucleation of calcium phosphate (CaP). Based on the crystalline and morphological characterization of the precipitates, the hydroxyapatite was the most stable crystalline phase of CaP, which was transformed from intermediate phases (such as dicalcium phosphate and amorphous calcium phosphate). This study paves the way for applying electrochemical membrane filtration system for P removal and recovery from wastewater.     

Biotreatment of produced water for removal of sulfides,organics, and toxicity

Applied Biochemistry and Biotechnology - Water coproduced with petroleum may contain sulfides and organic constituents that give the water an aquatic toxicity preventing surface discharge. A...     

Nitrogen and phosphorus co-doped carbocatalyst for efficient organic pollutant removal through persulfate-based advanced oxidation processes

Carbocatalysts doped with heteroatoms such as nitrogen or sulphur have been reported to be useful in persulfate-based advanced oxidation processes for organic pollutant removal. However, there is limited research on the effect of doping with phosphorus atoms on degradation performance. In this work, a new nitrogen and phosphorus-doped carbocatalyst (N, P-HC) was designed using hydrothermal carbonization followed by pyrolysis at 700 °C, with olive pomace as a carbon source, to degrade organic pollutants in the presence of peroxydisulfate (PDS). Experimental results showed that N, P-HC, with its large specific surface area (871.73 m².g⁻¹), high content of N-pyridinic and N-pyrrolic groups, and the presence of P-O-C and O-P-C bonds, exhibited high degradation performance (98% degradation of Rhodamine B (RhB) in 40 min, with an apparent rate constant (k_app) of 0.055 min⁻¹ and an excellent turnover frequency (TOF) of 0.275 min⁻¹). Quenching study and EPR analysis revealed that singlet oxygen generation (¹O₂) and direct electron transfer were the main reaction pathways for the non-radical pathway in the degradation of RhB. The improved catalytic efficiency in the N, P-HC/PDS/RhB system can be attributed to the synergistic effect between N and P atoms in the graphitic structure of the carbocatalyst, its high surface area, and the presence of oxygenated functional groups on the surface of the N, P-HC. The used N, P-HC carbocatalyst can also be efficiently recovered by heat treatment at 500 °C. Overall, this study presents a simple and environmentally friendly method for synthesizing a high-performance N, P co-doped olive pomace-based carbocatalyst for water decontamination through PS-AOPs processes.     

Monitoring and control of biological removal of phosphorus and nitrogen by flow-injection analysers in a municipal pilot-scale waste-water treatment plant

A flow-injection system is used for monitoring and control of a biological waste-water treatment plant with biological removal of phosphate and nitrate. The waste-water treatment plant is an activated sludge type on a pilot scale, with municipal waste water as the influent. The flow-injection system monitors the concentrations of phosphate, ammonia and nitrate in four places: in the inlet, in the outlet of the anaerobic pretreatment tank, in one of the aeration tanks and in the outlet of the plant. Sampling is carried out via a cross-flow filter system, based on an ultra-filtration membrane. The analysers employ highly pulsating, single-piston liquid chromatographic pumps. Synchronization of injection time and pump pulses eliminates the need for pulse-damping devices and ensures high reproducibility. The chemical methods are based on classical colorimetric methods. The measurement system has been designed with emphasis on long-term stability, low reagent consumption and minimum maintenance. To maintain stable, low flow-rates, on-line degassing has been installed for each reagent. Further, on-line standard calibration is being used to compensate for drift in the sensitivity of the analysers. The system is controlled by a PC, programmed in ASYST. The calibrated data is fed to a programmable logic controller (PLC), which also controls the pilot plant. A supervisory PC, programmed in Factory Link, stores and presents data. The measurements will be used for studies of different control strategies for the plant, e.g., rule-based control.     

Multi-pumping flow system for the determination of dissolved orthophosphate and dissolved organic phosphorus in wastewater samples

A multi-pumping flow system (MPFS) for the spectrophotometric determination of dissolved orthophosphate and dissolved organic phosphorus in wastewater samples is proposed. The determination of orthophosphate is based on the vanadomolybdate method. In-line ultraviolet photo-oxidation is employed to mineralise organic phosphorus to orthophosphate prior to detection. A solenoid valve allows the deviation of the flow towards the UV-lamp to carry out the determination of organic phosphorus.Calibration was found to be linear up to 20 mg P L⁻¹, with a detection limit (3s_b/S) of 0.08 mg P L⁻¹, an injection throughput of 75 injections h⁻¹ and a repeatability (R.S.D.) of 0.6% for the direct determination of orthophosphate. On the other hand, calibration graphs were linear up to 40 mg P L⁻¹, with a detection limit (3s_b/S) of 0.5 mg P L⁻¹, an injection throughput of 11 injections h⁻¹ and a repeatability (R.S.D.) inferior to 2.3% for the procedures involving UV photo-oxidation.     

Highly-active,metal-free,carbon-based ORR cathode for efficient organics removal and electricity generation in a PFC system

A highly-active,metal-free,carbon-based oxygen reduction reaction(ORR) cathode,i.e.,graphitized Ndoped carbon felt(GNCF),was prepared,for the first time,by in-situ modifying the doping species of polyacrylonitrile(PAN)-based carbon felt(CF) via a facile annealing process in Ar atmosphere.It was applied for dramatically enhanced organics degradation and electricity generation in a photocatalytic fuel cell(PFC) system.The GNCF showed enhanced specific surface area,improved graphitization and raised ratio of graphitic N,therefore resulting in excellently improved ORR performance compared to the CF.When applying the GNCF as a cathode in a PFC system,the proposed PFC showed significant improvement in degrading various model organic contaminants and outputing electricity simultaneously when compared with the PFC with CF.For instance,the apparent rate constant and electricity output efficiency showed ～10.6 times and ～7.2 times,respectively,improvement when using rhodamine B as model waste.Further improved performance was also achieved by aeration of air or O_2 due to the fu rther enhanced ORR.The proposed PFC was also efficient in a wide pH,and kept outsta nding stability in long-term utilization.     

Synthesis and application of silica and calcium carbonate nanoparticles in the reduction of organics from refinery wastewater

Oil refinery is one of the fast growing industries across the globe and it is expected to progress in the near future. The worldwide increase in the generation of refinery wastewater along with strict environmental regulations in the discharge of industrial effluent, persistent efforts have been devoted to recycle and reuse the treated water. The wastewater from the refining operation leads to serious environmental threat to the ecosystem. Therefore, this study aimed to synthesize silica (SiO₂) and calcium carbonate nanoparticles (CaCO₃) in the reduction of organics from refinery wastewater. The synthesized nanoparticles were employed in the reduction of chemical oxygen demand (COD) from refinery wastewater by studying the influence of solution pH, contact time, dosage of nanoparticles and stirring speed on adsorption performance. From the batch experimental studies, the optimized processing conditions for the reduction of COD using SiO₂ nanoparticles are pH 4.0, dosage 0.5 g, stirring speed 125 rpm and 90 min stirring time, and the corresponding values for CaCO₃ nanoparticles are pH 8.0, dosage 0.4 g, stirring speed 100 rpm and 90 min stirring time. The study demonstrates that SiO₂ and CaCO₃ nanoparticles have a promising future in the reduction organics from refinery wastewater in different pH regimes.     

Iron-based nanoparticles in wastewater treatment: A review on synthesis methods,applications, and removal mechanisms

Nanomaterial is an emerging material with potential technological impacts in various applications. It imposes great opportunities in various disciplines including wastewater remediation. Industrial wastewater is generated with anthropogenic activities and is the most environmental threat that needs remediation to overcome the environmental damages, thereby reducing human risks. Currently, several wastewater treatment techniques are applied and the utilization of nanomaterials for pollutant removal is an emerging technology. This is evident that the publication trends in the field of iron-based wastewater have been drastically increased. In this work, the overview of the preparation of iron-based nanoparticles, such as different polymorphs of iron-oxides, oxyhydroxides, iron hydroxide, and zero-valent iron nanoparticles are reviewed. In addition to the detailed discussion on the preparation of iron-based nanoparticles, their application on waste water treatment, removal mechanisms, advantages, and limitations are also assessed and discussed. Moreover, the iron-based nanoparticles' removal efficiency for specific pollutants and perspective in environmental remediation are also analyzed. Additionally, the advancements and future perspectives of iron-based nanoparticles are highlighted.     

Analysis of pharmaceuticals in wastewater and removal using a membrane bioreactor

Much attention has recently been devoted to the life and behaviour of pharmaceuticals in the water cycle. In this study the behaviour of several pharmaceutical products in different therapeutic categories (analgesics and anti-inflammatory drugs, lipid regulators, antibiotics, etc.) was monitored during treatment of wastewater in a laboratory-scale membrane bioreactor (MBR). The results were compared with removal in a conventional activated-sludge (CAS) process in a wastewater-treatment facility. The performance of an MBR was monitored for approximately two months to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of target compounds. Pharmaceuticals were, in general, removed to a greater extent by the MBR integrated system than during the CAS process. For most of the compounds investigated the performance of MBR treatment was better (removal rates >80%) and effluent concentrations of, e.g., diclofenac, ketoprofen, ranitidine, gemfibrozil, bezafibrate, pravastatin, and ofloxacin were steadier than for the conventional system. Occasionally removal efficiency was very similar, and high, for both treatments (e.g. for ibuprofen, naproxen, acetaminophen, paroxetine, and hydrochlorothiazide). The antiepileptic drug carbamazepine was the most persistent pharmaceutical and it passed through both the MBR and CAS systems untransformed. Because there was no washout of biomass from the reactor, high-quality effluent in terms of chemical oxygen demand (COD), ammonium content (N-NH₄), total suspended solids (TSS), and total organic carbon (TOC) was obtained.     

Simple UV/UV-visible method for nitrogen and phosphorus measurement in wastewater

A simple UV/UV-visible method is described for the determination of global nitrogen and total phosphorus in wastewater. This method includes two steps: first, the photo-oxidation of nitrogen and phosphorus forms into nitrate and orthophosphate ions, and their quantification by UV-visible spectrophotometry. Potassium peroxodisulfate is used as oxidant. The developed system consists of on-line association of UV photo-oxidation reactor with UV-visible detector. The conversion yields vary between 80 and 100% for both nitrogen compounds (ammonium, urea, amino acids, and other N-containing compounds), and phosphorus compounds (ADP, ATP, and other P-containing compounds). The time requires for nitrogen and phosphorus forms determination is no longer than 20 min.     

Comparison of APPI, APCI and ESI for the LC-MS/MS analysis of bezafibrate, cyclophosphamide, enalapril, methotrexate and orlistat in municipal wastewater

The applicability of three different ionization techniques: atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) was tested for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of five target pharmaceuticals (cyclophosphamide, methotrexate, bezafibrate, enalapril and orlistat) in wastewater samples. Performance was compared both by flow injection analysis (FIA) and on-column analysis in deionized water and wastewater samples. A column switching technique for the on-line extraction and analysis of water samples was used. For both FIA and on-column analysis, signal intensity and signal-to-noise (S/N) ratio of the target analytes in the three sources were studied. Limits of detection and matrix effects during the analysis of wastewater samples were also investigated. ESI generated significantly larger peak areas and higher S/N ratios than APCI and APPI in FIA and in on-column analysis. ESI was proved to be the most suitable ionization method as it enabled the detection of the five target compounds, whereas APCI and APPI ionized only four compounds.     

Electrohydrostatically driven flow and instability in a vertical hele-shaw cell

The electrohydrostatic capillary-driven flow of a viscous poorly conducting Newtonian fluid rising between conducting parallel plates is studied both theoretically and experimentally. By scaling the problem with a pressure and time derived by considering Maxwell stresses along the interface, it is determined that the dimensionless parameters governing the flow are the hydrostatic bond (Bo(H)), electrostatic bond (Bo(E)) and electrostatic Reynolds (Re(E)) numbers. A lubrication theory analysis, in the limit Re(E) --> 0, of the momentum balance leads to an analytical solution for the elapsed time versus interface position that is analogous to one derived by Washburn (1921) for the capillary pressure-driven flow of a fluid in cylindrical capillaries (Washburn, E. W. Phys. Rev. 1921, 17 (3), 273-283). Experiments are performed using silicone and castor oil at gap spacing less than the capillary length for two ranges of electrostatic Reynolds numbers 0.001 < Re(E) < 0.01 and 10 < Re(E) < 1000. The experimental results for the interface displacement as a function of elapsed time are compared with the theoretical predictions. At large electrostatic Reynolds numbers (>1), a convective instability is observed in plots of the interface position as a function of time. The propagating front also reveals an interfacial instability for large electrostatic Reynolds numbers coupled with large fluid displacements. The theory and experiments for the static rise height show good agreement with theory while the flow dynamics show good qualitative agreement in the applicable limits at low electrostatic Reynolds numbers.     

Removal of COD,aromaticity and color of a pretreated chemical producing industrial wastewater: a comparison between adsorption,ozonation, and advanced oxidation processes

A wide range of products are produced in the chemical producing industry such as textile dyes, chemicals, printing dyes and chemicals, paper chemicals, electrostatic powder dyes, and optical brighteners. The aim of this study is to investigate the treatability of chemical oxygen demand (COD), aromaticity, and color in the wastewater of this sector, where highly complex chemicals are used. Most of the studies in the literature are related to the treatment of synthetically prepared dyed wastewater. This study is important as it is carried out with real wastewater and gives results of many treatment methods. In the study, COD, UV-vis absorbance, and color values were attempted to be removed from the wastewater of a chemical producing industry that was pretreated by coagulation-flocculation. The COD value of the pretreated wastewater discharged to the central treatment system was restricted as 1000 mg/L. Pretreated wastewater characterization is as follows: COD: 2117 mg/L, UV-vis absorbance values at; 254 nm: 9.91, 280 nm: 8.65, 341 nm: 12.77, 436 nm: 5.01, 525 nm: 2.24, and 620 nm: 1.59. In the study, adsorption, ozonation, and advanced oxidation processes (Fenton and persulfate oxidation) were used to remove COD and UV-vis absorbance values (aromaticity, organics, and color). The method by which the best removal efficiency was obtained for all parameters was the adsorption process using powdered activated carbon (PAC). The equilibrium PAC dose was found as 6 g/L. At this adsorbent dose, the removal efficiencies of UV-vis absorbance values were all around 99% and the efficiency of COD removal was 77%. The Langmuir isotherm constants were found to be q_max= 30.4 mg/g and K_L = 487.9 (L/mg). The COD concentration at this adsorbent dose was 486 mg/L and wastewater was suitable for discharge to the central wastewater treatment plant in that region.     

Determination of chlorinated volatile organic compounds in water and municipal wastewater using headspace-solid phase microextraction-gas chromatography

The aim of this work was to develop a fast and simple analytical method for the determination of 14 chlorinated volatile organic compounds (VOCs) in water and wastewater samples. Headspace-solid-phase microextraction (HS-SPME) and gas chromatography (GC) were used for the determination of the VOCs. The extraction parameters were investigated in order to optimize the HS-SPME-GC method. The quality parameters of the method were also investigated.     

Response of aerobic sludge to AHL-mediated QS: Granulation,simultaneous nitrogen and phosphorus removal performance

The effects of different species and concentrations’ signal molecules on aerobic activated sludge system were investigated through batch experiments. Results showed that the fastest NH₄⁺-N oxidization rate and the most extracellular polymeric substances (EPS) secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone (C₆-HSL) into the aerobic activated sludge. Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing (AHLs-mediated QS), nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C₆-HSL. It was found that C₆-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge (AGS) system. Microbial compositions considerably shifted with long-term C₆-HSL-manipulation. Exogenous C₆-HSL-manipulation inhibited quorum quenching-related (QQ-related) activities and enhanced QS-related activities during the stable period. The proposed C₆-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS, which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.     

上游水库水体中氨氮、亚硝酸盐氮、硝酸盐氮、总氮的测定和关系探究

采用紫外分光光度法测定上游水库固定监测点位近两年采集样品的总氮、硝酸盐氮、氨氮、亚硝酸盐氮含量.对测试结果进行分析比较,探讨了上游水库水中总氮、硝酸盐氮、氨氮、亚硝酸盐氮的关系,从而为上游水库水质数据分析和综合评价提供一定参考.     

Analysis of hormone antagonists in clinical and municipal wastewater by isotopic dilution liquid chromatography tandem mass spectrometry

A comprehensive method was developed for the simultaneous trace analysis of ten hormone antagonist pharmaceuticals (raloxifene, exemestane, letrozole, anastrozole, mifepristone, finastride, tamoxifen, N-desmethyltamoxifen, clomiphene, and toremifene) in municipal sewage and hospital wastewater samples. The target compounds were firstly extracted using an Oasis HLB cartridge, followed by purification by an aminopropyl cartridge, and were then analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in positive ion mode. The recoveries for the analytes based on internal standard calibration in different test matrices ranged from 67.6 to 118.6% (with the exception of mifepristone in clinical wastewater samples), with relative standard deviations less than 20%. The method quantification limits of the ten pharmaceuticals were in the range 0.10–2.0 ng/L. Excluding exemestane and N-desmethyltamoxifen, eight drugs were detected at 0.20–195.0 ng/L in hospital wastewater and municipal wastewater samples from Beijing.