氯离子对污水厂出水COD测定的影响及消除

针对某污水处理厂出水COD测量中的氯离子干扰问题,建立了一种新的COD测定方法。结果表明,该方法能消除氯离子对COD测定的干扰,具有较高的准确性和稳定性,且设备简单、操作简便、成本低,适合污水厂高浓度氯离子出水中COD的检测。     

Modelling Escherichia coli concentrations in the tidal Scheldt river and estuary

Recent observations in the tidal Scheldt River and Estuary revealed a poor microbiological water quality and substantial variability of this quality which can hardly be assigned to a single factor. To assess the importance of tides, river discharge, point sources, upstream concentrations, mortality and settling a new model (SLIM-EC) was built. This model was first validated by comparison with the available field measurements of Escherichia coli (E. coli, a common fecal bacterial indicator) concentrations. The model simulations agreed well with the observations, and in particular were able to reproduce the observed long-term median concentrations and variability. Next, the model was used to perform sensitivity runs in which one process/forcing was removed at a time. These simulations revealed that the tide, upstream concentrations and the mortality process are the primary factors controlling the long-term median E. coli concentrations and the observed variability. The tide is crucial to explain the increased concentrations upstream of important inputs, as well as a generally increased variability. Remarkably, the wastewater treatment plants discharging in the study domain do not seem to have a significant impact. This is due to a dilution effect, and to the fact that the concentrations coming from upstream (where large cities are located) are high. Overall, the settling process as it is presently described in the model does not significantly affect the simulated E. coli concentrations.     

Total and methyl mercury transformations and mass loadings within a wastewater treatment plant and the impact of the effluent discharge to an alkaline hypereutrophic lake

Concerns over the fate and bioaccumulation of mercury (Hg) inputs to Onondaga Lake, a hypereutrophic lake in central New York, prompted an investigation into the concentrations and fluxes of Hg discharge from the Onondaga County Metropolitan Wastewater Treatment Plant (METRO WWTP). Discharge of methyl Hg (MeHg) is of concern because it is the form of Hg that readily bioaccumulates along the aquatic food chain. This study incorporated clean protocols for sampling and Hg analysis to evaluate: seasonal patterns in the concentrations of total Hg (THg) and MeHg in the WWTP unit processes; the production of MeHg within the unit processes of the WWTP; the overall fate of THg and MeHg within the WWTP; and the relative impact of the Hg discharged from the WWTP to Onondaga Lake. Concentrations of THg (range: 80-860 ng/L) and MeHg (0.7-17 ng/L) in raw sewage were highly variable, with higher concentrations observed in the summer months. The dynamics of THg though the WWTP were correlated with total suspended solids (TSS). As a result, the majority of the THg removal (55%) occurred during primary treatment. Overall, about 92% of the THg entering the plant was removed as sludge, with volatilization likely a minor component of the overall Hg budget. The transformation of MeHg through the plant differed from THg in that MeHg was not correlated with TSS, and displayed strong seasonal differences between winter (November to April) and summer (May-October) months. During the summer months, substantial net methylation occurred in the activated sludge secondary treatment, resulting in higher MeHg concentrations in secondary effluent. Net demethylation was the dominant mechanism during tertiary treatment, resulting in removal of substantial MeHg from the secondary effluent. The overall MeHg removal efficiency through the plant was about 70% with more efficient removal during summer months. Sediment trap collections made below the epilimnion of Onondaga Lake indicated average deposition rates of 12 μg/m²-day for THg and 0.33 μg/m²-day for MeHg. These deposition rates are more than an order of magnitude higher than the thermocline area normalized external loads from METRO effluent (0.85 μg/m²-day for THg, 0.05 μg/m²-day for MeHg). Our findings indicate that the impact of the discharge from METRO is relatively small, contributing about 10-15% of Hg to the total gross Hg input to the hypolimnion of the lake.     

Behavior of Fe, Mn, Cu and Cd in the duwamish river estuary downstream of a sewage treatment plant

The behavior of dissolved Fe, Mn, Cu and Cd in the Duwamish River downstream of a sewage treatment plant located near Seattle, Washington, was investigated in three distinct zones: (1) immediately downstream of the effluent outfall, (2) further downstream in the freshwater portion of the river and (3) in the estuarine mixing zone. A three-end-member tracer model utilizing salinity and dissolved inorganic nitrogen was developed to distinguish physical mixing processes from biogeochemical reactions. The results of this investigation indicate that Fe was removed from the dissolved phase onto particulates near the plant. Although no additional reactions controlled the distribution of dissolved Fe, Mn and Cu in the freshwater portion of the river, Cd was removed from the dissolved phase. In the estuarine mixing zone, a significant fraction of the dissolved Fe and Cu was removed from solution, while Mn and Cd desorbed from particulates. The chemical forms of the trace metals rather than their sources appear to determine their participation in these reactions.     

天津市长泰河和复兴河水环境综合治理设施的应用

天津市长泰河和复兴河是天津市重要的二级河道,由于其水体较好的流动性、自净性和连通性,选择此两条河道进行水环境综合治理设施的应用与实践。对不同的水环境综合治理设施进行介绍,详述其特点、应用特征以及布置方案,目的在于铺陈不同的设施技术在河道应用所带来的变化,对水体的改善程度以及综合应用后的处理效果,为河道水体治理提供更多多元化的思考建设方式。     

Evaluation of ozone induced biodegradability of wastewater treatment plant effluent

A long terre BOD test was used for quantitative determination of biodegradability induced by ozone on refractory organic matter remaining in solution after conventional biological and lime treatment. The improvement in biodegradability cansed by ozonation can be assumed as removing inhibitory effects due to changes in molecular structure. In all biodegradability tests of ozonated efltuents acclimation was required. When a seed material consisting of micro-organisms already acclimated is used, the iag period disappears.     

邻江LNG液化厂地基处理研究

某拟建邻江LNG液化厂场地下方有较厚的淤泥质土层,需进行大面积的地基处理,对此提出了不同的地基处理方案,经过对比研究,决定采用粉喷桩方案对地基进行处理,并对粉喷桩的设计要求进行了计算,对其施工要点进行了总结,为今后类似工程提供了有益的借鉴。     

城市污水厂二级处理出水内电解深度处理技术研究

采用内电解技术对城市污水处理厂出水进行深度处理,研究了pH值、废水在反应器中的停留时间等因素对处理效果的影响,并采用增加催化剂的措施提高了工艺的处理效果,解决了板结问题.试验结果表明,污水处理厂二级出水经内电解法处理后,脱色率可达90%以上,TP去除率可达90%左右,CODcr去除率也可达60%左右,内电解技术是一种经济高效的城市污水二级处理出水深度处理技术.     

Direct and indirect photolysis of sulfamethoxazole and trimethoprim in wastewater treatment plant effluent

The photolysis of two antibacterial compounds, sulfamethoxazole and trimethoprim, was studied in wastewater effluent. The rate of loss of sulfamethoxazole was enhanced in wastewater effluent due to indirect photolysis reactions, specifically reactions with hydroxyl radicals and triplet excited state effluent organic matter. Photolysis in the presence of natural organic matter, however, did not lead to enhanced degradation of sulfamethoxazole. Trimethoprim was also found to be susceptible to indirect photolysis in wastewater effluents, with hydroxyl radical and triplet excited effluent organic matter being the responsible species. Deoxygenation of solutions led to more rapid direct photolysis of sulfamethoxazole and trimethoprim, indicating that direct photolysis proceeds through a triplet excited state, which was verified by demonstrating that trimethoprim is a singlet oxygen sensitizer. In the wastewater effluents tested, photolysis could be apportioned into direct photolysis (48% for sulfamethoxazole, 18% for trimethoprim), reaction with hydroxyl radicals (36% and 62%, respectively) and reaction with triplet excited effluent organic matter (16% and 20%, respectively). These results indicate that allowing photolysis in wastewater stabilization ponds or wastewater treatment wetlands may lead to enhanced pharmaceutical removal prior to discharge and that effluent organic matter has different photoreactivity than natural organic matter.     

污水处理厂出水氨氮异常的分析与控制

针对某污水处理厂出水氨氮异常的突发事件,分别对该事件发生的可能原因进行了分析,分别为进水氨氮突然升高和硝化茵流失所致,并根据分析结果采取了针对性的控制措施,取得了良好的效果,可为国内其他污水处理厂应对该类异常现象提供参考。     

The physicochemical speciation of Cd, Pb, Cu, Fe and Mn in the final effluent of a sewage treatment works and its impact on speciation in the receiving river

A scheme for the speciation of metals in freshwaters has been applied to the analysis of the final effluent from a sewage treatment plant and to the receiving river upstream and downstream of the effluent outfall. The treatment plant was selected because of the high influent and effluent concentrations of Cd. The metal speciation patterns in the effluent are interpreted primarily in terms of organic interactions, which appear to be exerting a solubilizing effect on Cd and Cu, but not on the Pb and Fe which are principally associated with the particulate size fraction (> 12 μm). The influx of metals with the sewage effluent alters the speciation pattern in the river. A large part of the Cd is added to the smallest size fraction (< 0.015 μm). However, the major part of each metal, with the exception of Mn, is associated with the colloidal and particulate size fractions, thus minimising the immediate toxic significance to aquatic life.     

深圳市罗芳污水处理厂出水臭氧脱色灭菌中试

从臭氧产生的机理出发,并以污水处理厂二级出水消毒和对水体的除臭脱色为例,介绍了臭氧的实际应用情况,以及存在的问题,指出由于臭氧具有强氧化性,易分解,在污水处理中值得推广应用。     

Influence of temperature and river discharge on water quality of the western scheldt estuary

Dissolved oxygen concentrations and information on the nitrification process collected respectively during a 14- and a 5-year period in the self-purifying part of the Western Scheldt estuary have been studied. In the polluted part of the stream, ammonium concentrations over the period 1967–1977 have been considered as well.This paper demonstrates the high variability of these 3 parameters (oxygen, start of the nitrification process, ammonium) owing to the hydrological conditions: temperature and river discharge.Neither the levels of ammonium in the polluted upper part of the stream, nor the concentrations of nitrate and dissolved oxygen in the recuperation part of the Scheldt estuary have changed significantly during the periods studied (respectively 5, 10 and 14 years). A relation between these parameters and time could be hidden by hydrological factors.Water quality of a stream can be assessed by interpreting oxygen, nitrate, and ammonium concentrations, only if all environmental and hydrodynamical parameters are known simultaneously.     

Exploitation of aggregates in the river po basin,near Turin,Italy, and its impact on the environment

The study carried out jointly by the Politecnico di Torino and the Ufficio Cave of Regione Piemonte examined the most troublesome interferences between quarry exploitation and other land uses alongside the river Po, south of Turin. Here a great number of large alluvial aggregate quarries, whose excavations extend below the water table, have long been active. Detailed geological and topographical investigations have been carried out, together with geophysical prospecting work (by electrical methods) and hydraulic tests on wells. The results of the investigations have permitted the setting up for the quarries involved of rational guidelines for the protection of the groundwater resources and of soil stability. The necessity of systematic preliminary studies, according to the law presently in force, is stressed for new quarries to be opened. Investigations should also involve an adequate number of exploration drillings and water pressure measurements, to determine the amount and the quality of the alluvial deposits as well as the hydraulic characteristics of the aquifers and the geotechnical properties of the ground where the excavation work has to be made. A rational program of land recovery, and an exploitation plan respecting other land uses, can be set only in the light of the aforesaid studies.     

污水处理厂消毒方式造成的环境影响及其防治对策

污水处理厂的消毒方式既有物理消毒方法,也有化学消毒方法．通过介绍《室外排水设计规范》（GB50014—2006）中三种污水处理厂消毒方式,对这三种消毒方式所造成的环境影响进行了简要分析,并提出了相关的防治措施。     

污水厂出水SS偏高问题研究及措施

研究了上海某A/B/C活性污泥工艺污水处理厂出水SS偏高的问题,对影响出水SS的主要影响因素进行了综合分析,并提出了工艺调整措施,在实际运行中取得了较好的效果。     

Simultaneous colour and DON removal from sewage treatment plant effluent: Alum coagulation of melanoidin

The aim of this study was to detect and characterise melanoidin in sewage treatment plant (STP) effluent, and to study the ability of alum coagulation to remove the colour and dissolved organic nitrogen (DON) associated with melanoidin. The melanoidin is non-biodegradable due to the complex cyclic based structure and thus it directly contributes to effluent nitrogen concentrations from the sewage treatment plant (STP). Lowering of effluent total nitrogen limits and the link between colour and chlorinated disinfection by-products have therefore driven a need to understand the structure, properties and treatability of DON species found in STP effluent.The focus of this paper is the refractory coloured, organic nitrogen compound melanoidin. Wetalla STP effluent has relatively high colour (170 mg-PtCo L⁻¹) and DON (2.5 mg L⁻¹) for a biological nutrient removal STP, owing to an industrial supply of melanoidin containing molasses fermentation wastewater. Alum coagulation jar tests were performed on synthetic melanoidin solution, STP effluent containing melanoidin (Wetalla, Toowoomba, Australia) and STP effluent free of melanoidin (Merrimac, Gold Coast, Australia) to examine the treatability of melanoidin and its associated colour and DON content when present in STP effluent.The removal of melanoidin from STP effluent resulted in significant colour and DON reduction. An alum dose of 30 mg L⁻¹ as aluminium was sufficient to reach maximum removal of colour (75%), DON (42%) and dissolved organic carbon (DOC) (30%) present in melanoidin containing STP effluent. Alum was shown to preferentially remove DON with a molecular weight >10 kDa over small molecular weight DON. Fluorescence excitation-emission matrix examination of the humic compounds present in the STP effluent indicated that melanoidin type humic compounds were more readily removed by alum coagulation than other humic compounds.     

城市河道的水环境生态治理对策分析

从河道水环境存在的主要问题入手,根据城市河道的治理原则,分析了当前城市河道治理的技术现状,并从整治规划、雨污分流处理、一体化管理等方面,提出了水环境生态治理的相关对策,从而改善河道水质,促进城市水环境的良性发展。     

Fate of effluent organic matter and DBP precursors in an effluent-dominated river: A case study of wastewater impact on downstream water quality

The impact of treated wastewater discharges on downstream water quality was evaluated in an effluent-dominated stream in the Southwest USA. The fate and transport of effluent organic matter (EfOM) and disinfection by-product (DBP) precursors was studied. Nitrification and biodegradation were important mechanisms. Changes in DBP formation potential along the river appeared to correlate with dissolved organic carbon (DOC) and organic nitrogen concentrations and specific ultraviolet absorbance. The mean oxidation state of carbon (MOC) decreased in value along the river. MOC decreases paralleled decreases in the biodegradability of residual DOC (i.e., lower biodegradable DOC/DOC ratio). The EfOM was biodegradable by up to 40 percent, both in the stream and in a laboratory reactor, and many DBP precursors (e.g., haloacetonitriles, certain nitrosamines) decreased in concentration. Alternatively, the DBP yields for trihalomethanes or haloacetic acids either remained the same or increased slightly, suggesting that these precursors were part of the recalcitrant organic matter (OM).     

污水处理厂恶臭防治对策及环境影响评价的研究

城市污水处理厂的恶臭严重影响了污水处理厂周围居民的日常生活,通过对城市污水处理厂的恶臭来源和国内外污水处理厂恶臭防治措施的现状分析,重点从环评角度对污水处理厂恶臭的环境影响评价方法进行了研究,从实测、嗅闻调查以及大气防护距离的确定三个角度进行综合全面的评价分析.