pH、盐度对微生物还原硫酸盐的影响研究

采用厌氧生物处理工艺,研究了在不同盐度下pH连续降低对硫酸盐还原和有机物去除率的影响。实验结果表明,硫酸盐还原菌有很强的适应pH变化的能力,在pH值达到4以下仍有60％的硫酸盐去除率。NaCl浓度由4g／L增加到50g／L抑制了各厌氧菌的活性,导致硫酸盐和有机物去除率的下降,但硫酸盐还原菌耐受性高于产甲烷菌等其他厌氧菌,在NaCl浓度为50g／L下,硫酸盐去除率能达到50％,而有机物去除率则低于30％。qRT—PCR表明了系统菌落中SRB随着环境的变化情况与化学指标结果相一致,该反应器体系中SRB在整个厌氧菌群落中只占了很小部分。     

电化学工艺处理有机废水的研究进展

综述了目前国内外学者在二维电极和三维电极的开发和改进方面的研究成果,指出了电化学氧化技术和电极材料的主要研究方向和发展趋势.提出为解决电化学水处理技术中提高电催化效率和延长电极寿命的问题,当前研究的主要方向应集中在阳极材料、反应器结构和处理工艺方面.     

催化湿式氧化预处理造纸黑液

采用连续式固定床反应器,利用自制稀土类复合金属氧化物催化剂对草浆造纸黑液进行了催化湿式氧化(CWAO)预处理研究.通过正交实验确定了最佳工艺条件为:进水COD 40 800 mg/L,空速0.8h-1,反应温度260℃,反应压力6.5 MPa.在此最佳条件下进行实验,COD去除率达90％.经CWAO工艺处理后,草浆造纸...     

三元复合驱采出水中悬浮固体的控制方法

采用向三元复合驱采出水中加入水质稳定剂的方法有效降低采出水中悬浮固体的质量浓度。实验结果表明,将100 g采出水依次经滤纸和孔径为0.45μm的醋酸纤维素膜过滤后,加入1.0 g WSBL-3型水质稳定剂,混合均匀后置于80℃的水浴中静置4 h,取出后再置于40℃的水浴中静置5 min,由此可将采出水中的悬浮固体质量浓度由107 mg/L降至2 mg/L。     

化工园区生化出水氯代烃污染物的臭氧氧化降解

以化工园区污水处理厂生化出水为背景水样,考察了臭氧氧化对2,4,6-三氯酚、氯苯、1,2-二氯苯、对硝基氯苯、四氯酞酸5种特征氯代烃污染物的降解效果,并对其降解动力学进行了分析。实验结果表明:臭氧对2,4,6-三氯酚和氯苯的降解效果最好,反应30 min时的去除率均接近100%,其次为1,2-二氯苯和对硝基氯苯,反应30 min时的去除率分别为95.7%和36.0%,最差为四氯酞酸,反应30 min时的去除率仅为8.9%;臭氧对2,4,6-三氯酚和对硝基氯苯的降解符合零级动力学方程,对氯苯和1,2-二氯苯的降解符合一级动力学方程,对四氯酞酸的降解符合二级动力学方程。     

A Two-Stage Particle Swarm Optimization Algorithm for MPPT of Partially Shaded PV Arrays

The power-voltage (P-V) characteristic curves of a PV array are nonlinear and have multiple peaks under partially shaded conditions (PSCs). This paper proposes a novel maximum power point tracking (MPPT) method for a PV system with reduced steady-state oscillation based on a two-stage particle swarm optimization (PSO) algorithm. The grouping method of the shuffled frog leaping algorithm (SFLA) is incorporated in the basic PSO algorithm (PSO-SFLA), ensuring fast and accurate searching of the global extremum. An adaptive speed factor is also introduced into the improved PSO to further enhance its convergence speed. Test results show that the proposed method converges in less than half the time taken by the conventional PSO method, and the power is improved by 33% under the worst PSCs, which confirms the superiority of the proposed method over the standard PSO algorithm in terms of tracking speed and steady-state oscillations under different PSCs.     

A comparison of pretreatments on release of sugars from sweet sorghum bagasse for bioethanol production

Dilute acid pretreatment and steam pretreatment were evaluated for maximum sugars release and ethanol production from sweet sorghum bagasse (SSB). The fermentation potential of the condensate and hydrolysate obtained from steam pretreatment (10 kg/cm², 10 minutes) and dilute acid hydrolysis (1% (w/w) sulphuric acid, 25% substrate loading) respectively, was checked with Pichia stipitis NCIM 3497 and Debaryomyces hansenii sp. Ethanol production and yield using acid hydrolysate was higher with Debaryomyces hansenii sp. (28.4 g/L and 0.37 g/g respectively) as compared with Pichia stipitis NCIM 3497 (21.9 g/L and 0.29 g/g respectively).     

PbO_2复合电极预处理甲苯二胺废水

通过涂覆—热分解法与电沉积法制备了β-PbO_2/α-PbO_2/SnO_2-Sb2O3/Ti复合电极(PbO_2复合电极),采用X射线衍射(XRD)、扫描电子显微镜(SEM)、循环伏安法(CV)、线性极化法(LSV)和加速寿命试验对电极进行表征。将PbO_2复合电极用于处理甲苯二胺(TDA)废水,考察了电解质浓度、电流密度对TDA降解效果的影响。实验结果表明:α-PbO_2呈梭状,β-PbO_2呈花菜状,多层结构的PbO_2电极利于提高电极的稳定性和活性;PbO_2复合电极的析氧电位(1.9 V)明显高于TDA的氧化电位(1.28 V),其使用寿命长达486 d;在电流密度为60 m A/cm2、Na2SO4质量浓度为10 g/L、电解时间为240 min的条件下,对COD为4 791.74 mg/L、TDA质量浓度为486.4mg/L的废水进行处理,TDA去除率高达97.3%,COD去除率可达88.1%。     

臭氧氧化法降解聚氯乙烯离心母液废水中3种有机物

以聚氯乙烯离心母液废水中含量较高的3种有机物(聚乙烯醇、异辛醇和α-甲基苯乙烯)作为目标物,考察臭氧氧化工艺对3种有机物的去除效果,同时考察反应时间、臭氧投加量和初始pH对处理效果的影响。实验结果表明,臭氧氧化处理3种废水的最佳反应时间和臭氧投加量分别为:聚乙烯醇25 min,136 mg/L;异辛醇60min,312 mg/L;α-甲基苯乙烯60 min,32 mg/L。在此条件下,3种有机物的去除率分别为98%、85%和95%。此外,碱性条件有助于臭氧氧化工艺对3种有机物的降解。产物分析结果表明,经臭氧氧化,聚乙烯醇断链后进一步反应生成了草酸单乙酯,异辛醇和α-甲基苯乙烯分别生成了和苯乙酮。     

Detection of DDT and its metabolites in two estuaries of South China using a SPME-based device: First report of p,p′-DDMU in water column

A solid-phase microextration-based sampling method was employed to determine the concentrations of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE) and 1-chloro-2,2-bis(p-chlorophenyl)ethene (DDMU), in two estuarine bays, Daya Bay and Hailing Bay, of South China. Six DDT components including p,p′-DDT, o,p′-DDD, p,p′-DDD, o,p′-DDE, p,p′-DDE, and p,p′-DDMU were detected in Hailing Bay, while only p,p′-DDD was found in Daya Bay. p,p′-DDD was the most abundant DDT component in both bays, sharply different from the previous finding in the water column of the Palos Verdes Shelf, California, USA that p,p′-DDE was prevalent. In addition, the occurrence of p,p′-DDMU (with a range of 0.047-0.21 ng/L in Hailing Bay) has not been reported around the globe, and its presence in our study region appeared to stem from dehydrochlorination of p,p′-DDD, favored under aerobic conditions, but further investigations are clearly needed to confirm the mechanism for generation of DDMU in estuarine environments.