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关键词： Sulfamethazine   Horizontal flow-anaerobic immobilized biomass bioreactor   Transformation products   SPE-online   LC-MS/MS  

摘要： Sulfamethazine (SMZ) is an antibiotic from sulfonamides class widely used in veterinary medicine and reported in wastewater and sewage. Thus, it is essential to study technologies to reduce SMZ present in the aquatic environment. Anaerobic bioreactors are a low-cost technology applied for wastewater treatment. The objective of this paper is to study kinetics parameters related to SMZ removal using a horizontal flow-anaerobic immobilized biomass reactor (HAIR) and to evaluate its transformation products formed during this treatment. The bioreactor was operated at mesophilic condition with a hydraulic retention time of 12 h. The removal of SMZ was evaluated at three different concentrations: 200 ng L-1 (phase I), 400 ng L-1 (phase II) and 600 ng L-1 (phase III). The apparent first-order removal constant obtained for chemical oxygen demand was 0.885 +/- 0.094 h(-1) while SMZ showed a removal constant of 0.356 h(-1). SMZ was removed with an efficiency of 56.0 +/- 13.0 % (phase I);62.0 +/- 12.0 % (phase II) and 62.0 +/- 6.00 % (phase III). Seven transformation products were detected and one of these with m/z 233 is reported for the first-time. The HAIB bioreactor has a potential to assist in wastewater treatment to remove contaminants at ng L-1 concentration level.

关键词： Wastewater treatment   Pharmaceuticals   Membrane bioreactor   Adsorption   Surface expression  

摘要： Environmental release and accumulation of pharmaceuticals and personal care products is a global concern in view of increased awareness of ecotoxicological effects. Adsorbent properties make the biopolymer melanin an interesting alternative to remove micropollutants from water. Recently, tyrosinase-surface-displaying Escherichia coli was shown to be an interesting self-replicating production system for melanin-covered cells for batch-wise absorption of the model pharmaceutical chloroquine. This work explores the suitability of these melanin-covered E. coli for the continuous removal of pharmaceuticals from wastewater. A continuous-flow membrane bioreactor containing melanized E. coli cells was used for adsorption of chloroquine from the influent until saturation and subsequent regeneration. At a low loading of cells (10 g/L) and high influent concentration of chloroquine (0.1 mM), chloroquine adsorbed until saturation after 26 +/- 2 treated reactor volumes (39 +/- 3 L). The average effluent concentration during the first 20 h was 0.0018 mM, corresponding to 98.2% removal. Up to 140 +/- 6 mg chloroquine bound per gram of cells following mixed homo- and heterogeneous adsorption kinetics. In situ low pH regeneration released all chloroquine without apparent capacity loss over three consecutive cycles. This shows the potential of melanized cells for treatment of conventional wastewater or highly concentrated upstream sources such as hospitals or manufacturing sites.

关键词： biofilm membrane bioreactor   membrane fouling   coagulants   membrane flux enhancement   multivariate statistics   factorial experimental design  

摘要： Considering new legislative and economic restrictions caused by the water crisis, this work focuses on a more efficient wastewater treatment process, which combines biological treatment in a moving bed biofilm system with a membrane bioreactor (BF-MBR) and coagulation, particularly addressing fouling alleviation in the separation stage. The study justifies the positive impact of coagulant dosing in BF-MBR regarding membrane flux and fouling rate. Statistical techniques connect the results of coagulation and membrane separation experiments with properties of mixed liquor, obtained after biotreatment in the representative pilot plant and characteristics of prepolymerized and non-prepolymerized inorganic coagulants. Research results substantiate the need for a pH-controlled coagulation of mixed liquor in BF-MBR depending on coagulant type, which influences charge, hydrophobicity and size of flocs and organic content of the system. It is suggested, that the adsorption/charge neutralization mechanism dominates in flux enhancement in BF-MBR, giving the best results in the case of prepolymerized aluminium coagulants. Together with high quality of permeate, the application of prepolymerized aluminium chloride of medium basicity entails a tenfold increase in filtration time of the membrane separation cycle and increases net membrane flux by 30-56%. The results of the study are practically significant for the development of an automated control system for BF-MBR, optimizing treatment rates together with membrane separation efficiency.

关键词： carbon fibres   denitrification   nitrous oxide emission   swine wastewater  

摘要： Nitrous oxide (N2O) is a potent greenhouse gas that is emitted from wastewater treatment plants. To reduce emissions of N2O from swine wastewater treatment plants, we constructed an experimental aerobic bioreactor packed with carbon fibres (ca. 1 m(3) bioreactor) as an alternative to conventional activated sludge treatment. The N2O emission factor for the aerobic bioreactor packed with carbon fibres (CF) was 0.002 g N2O-N/g TN-load and the value for the typical activated sludge (AS) reactor was 0.013 g N2O-N/g TN-load. The CF treatment method achieved more than 80% reduction of N2O emissions, compared with the AS treatment method. The experimental introduction of a CF carrier into an actual wastewater treatment plant also resulted in a large reduction in N2O generation. Specifically, the N2O emission factors decreased from 0.040 to 0.005 g N2O-N/g TN-load following application of the carrier. This shows that it is possible to reduce N2O generation by more than 80% by using a CF carrier during the operation of an actual wastewater treatment plant. Some bacteria from the phylum Chloroflexi, which are capable of reducing N2O emissions, were detected at a higher frequency in the biofilm on the CF carrier than in the biofilm formed on the AS reactor.

关键词： Fe   废水   生物反应器   缺氧污泥   迁移转化   形态学   生物絮凝性  

摘要： 为了研究铁元素对A^2O工艺污泥絮凝性的影响,考察Fe^(3+)在污泥上清液、胞外聚合物(extracellular polymeric substances,EPS)与底泥(Pellet)中的分布和迁移转化规律,结合三维荧光光谱(3D-EEM)、原子吸收和X射线衍射仪(XRD)分析Fe的存在形态和结构特征,揭示Fe^(3+)与微生物代谢产物的作用机制,探索Fe^(3+)对脱氮除磷效率的影响。结果表明:低浓度Fe^(3+)(<10 mg·L^(-1))能够提高COD和TN去除率,促进微生物活性,增强污泥生物絮凝性;高浓度Fe^(3+)(10～40 mg·L^(-1))则抑制微生物活性,使EPS总量升高,污泥絮体脱稳,LB、TB层PN/PS是影响污泥絮凝性的关键因素;Fe^(3+)的投加强化生物除磷效率,当Fe^(3+)浓度为40 mg·L^(-1)时,TP去除率为93%。Fe^(3+)在污泥混合液中的分布规律为TB>上清液>LB>SMP,Fe^(3+)在生物体内富集累积,能够改变EPS各层的组分。

关键词： Biofilm   Fluidized bed bioreactor   High rate   Water treatment   Wastewater treatment  

摘要： Fluidized bed bioreactors (FBR) are characterized by two-phase mixture of fluid and solid, in which the bed of solid particles is fluidized by means of downward or upward recirculation stream. FBRs are widely used for multiple environmental engineering solutions, such as wastewater treatment, as well as some industrial applications. FBR offers many benefits such as compact bioreactor size due to short hydraulic retention time, long biomass retention on the carrier, high conversion rates due to fully mixed conditions and consequently high mass transfer rates, no channelling of flow, dilution of influent concentrations due to recycle flow, suitability for enrichment of microbes with low Km values. The disadvantages of FBRs include bioreactor size limitations due to the height-to-diameter ratio, high-energy requirements due to high recycle ratios, and long start-up period for biofilm formation. This paper critically reviews some of the key studies on biomass enrichment via immobilisation of low growth yield microorganisms, high rates via fully mixed conditions, technical developments in FBRs and ways of overcoming toxic effects via solution recycling. This technology has many potential new uses as well as hydrodynamic characteristics, which enable high-rate environmental engineering and industrial applications. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： 发酵系统   生物反应器   工艺设计   原料药   生物制品  

摘要： 结合新版GMP和ASME BPE等法规对生物发酵系统的要求,运用新的生物反应器和发酵系统设计理念,对传统的生物发酵系统的接种、取样、补料、移种、CIP在位清洗、废液及尾气处理等工艺设计进行优化,使其符合相关法规要求,更好地应用于原料药、生物制品等行业的发酵生产。

关键词： aeration   energy consumption   membrane bioreactors  

摘要： Increasing stringency of environmental discharge standards has triggered an industry-wide inclination towards membrane bioreactors over conventional activated sludge processes to ensure fulfilment of environmental discharge criteria. Yet, despite its plentiful advantages, high aeration costs remain as a key deterrent to the widespread adoption of the MBR technology. This backdrop created an impetus for a wastewater treatment company to develop an efficient MBR air scouring protocol that can be realized in existing plants without retrofitting. Known as pulsed cyclic aeration, plant trial applications have demonstrated that fouling control and aeration savings can be improved by >30%, resulting in scouring energy consumptions that can be as low as 0.049 kWh/m(3).

关键词： Activated sludge   Membrane bioreactor   Polyelectrolyte   Polyacrylamide   Charge density   Volume reduction  

摘要： Improvement of sludge dewaterability is greatly hindered by the presence of large amounts of interstitial water molecules trapped in the sludge as a result of strong hydrophilic characteristics. This study has investigated the influence of six different polyacrylamide (PAM) flocculants with different molecular architecture (linear, slightly and highly branched), charge density (CD) and molecular weight (MW) on the electro-kinetics and dewatering of highly stable industrial membrane bioreactor (MBR) sludge. The Impact of PAM on flocculation is manifested in the supernatant turbidity, particle zeta potential, sludge capillary suction time (CST), floc size and settleability. Turbidity removal and reduction in zeta potential are used to identify the optimum polymer dose. An optimum dose of 70 mg.L-1 has been determined for linear PAM of 40% CD. However, a highly-branched PAM, with the same CD, has shown an optimum value of 30 mg.L-1. In all cases, a turbidity removal of more than 99% and CST reduction of 51-64% is attained;the linear PAMs have resulted in the highest CST reduction. Higher PAM doses have resulted in larger flocs and the maximum particle size is observed at the saturation point. The reduction in sludge volume relates with the floc size and PAM dose. For sludge conditioning and dewaterability, highly branched PAM with low MW has shown superior performance over linear high MW PAM. Enhancement of flocculation and dewatering is correlated with the surface charge neutralization and bridging mechanisms.

关键词： Spatiotemporally anaerobic/semi-aerobic bioreactor   Domestic solid waste   Treatment process   Treatment efficiency   Rural areas  

摘要： To meet the requirements of domestic solid waste treatment and technological upgrading of bioreactors, a spatiotemporally anaerobic/semi-aerobic bioreactor (STASAB) was designed. The STASAB took full advantages of anaerobic and semi-aerobic bioreactors by the sequential alternation of anaerobic and semi-aerobic operation and by recirculation of mixed leachate from different-stage bioreactors. Results indicated that after the start-up stage, the pH of leachate in the STASAB always remained higher than 6.88, even in the hydrolysis and acidogenesis stage. The maximum total nitrogen concentration in the STASAB was 1461 mg.L-1, which was merely half that of the sequentially anaerobic/semi-aerobic bioreactor (SASAB) and had no adverse effects on the anaerobic process. Nitrogen removal in the STASAB reached 92.3%-95.5% when operated in the semi-aerobic phase and even reached 49.4% when operated in the anaerobic phase. The peak concentration of chemical oxygen demand was much lower and the anaerobic digestion lag time was much shorter in the STASAB than in the SASAB. The period of rapid biogas production in the STASAB was double that of the SASAB, which resulted in a 70% increase in biogas generation. Moreover, leachate could be exhausted by evaporation in just 3-5 months during the semiaerobic phase. Therefore, the STASAB can eliminate acidogenic and ammonia inhibition during solid waste treatment, enhance the rate and extent of organic waste decomposition, rapidly initiate methanogenesis, enhance methane generation, and achieve zero leachate discharge (excluding rainfall infiltration). The STASAB is an efficient and feasible technique for treating domestic solid waste in rural areas. (C) 2019 Published by Elsevier Ltd.