猎德污水处理厂污泥系统除臭工程设计

根据已建污水处理厂的实际情况,对污泥浓缩池采用加高盖臭气收集方法,对污泥脱水间采用重点区域强化抽吸的臭气收集方法,并采用洗涤-生物滤床联合除臭工艺进行臭气处理;对污泥码头采用喷洒天然植物提取液除臭工艺进行除臭.介绍了除臭工程的设计参数和运行情况,工程实施后,污水处理厂的恶臭状况得到明显改善.     

高浓度制药废水处理工程实例

针对某制药公司废水主要成分为DMF、三乙胺、四氢呋喃等,新建1座废水处理厂,采用化学氧化—兼氧—好氧—接触氧化处理工艺.该类制药废水含盐量较高,需经稀释后再进行生化处理,经生化处理后二沉池出水可达《污水综合排放标准》(GB 8978-1996)二级标准.处理工艺恶臭气体采用收集—预处理—低温等离子处理—后处理—高空排放工艺进行处理,处理后可达《恶臭污染物排放标准》(GB 14554-93)二级排放标准.     

不同污水处理工艺对磺胺抗生素去除效果与生态风险评估

采用固相萃取-高效液相色谱-串联质谱(SPE-HPLC-MS/MS)法调查研究了磺胺嘧啶(SD)、磺胺甲恶唑(SMX)、磺胺甲嘧啶(SMZ)、磺胺噻唑(STZ)、磺胺氯哒嗪(SPD)在北京市某污水处理厂7个代表性工艺单元中的浓度水平、去除特征,并运用风险熵(RQ)评估了总出水中残留目标物对受纳水体的生态风险。结果表明SD、SMX、SMZ、STZ和SPD在污水处理厂总进水中的平均浓度分别为199.0ng/L、288.4ng/L、19.3ng/L、2.1ng/L和5.1ng/L,在紫外消毒(UV)工艺出水中SD、SMX、SMZ的平均浓度分别为6.3ng/L、16.9ng/L和1.2ng/L,未检测到STZ和SPD。表明本污水处理厂能够完全去除STZ和SPD,对SD、SMX和SMZ的去除率分别为96.8%、94.2%和93.9%。除曝气沉砂池和二沉池工艺对个别目标物存在负去除率以外,5种磺胺抗生素经处理后,主要集中在二级与三级处理。5种磺胺类抗生素负荷量存在一定的周内变化。污水处理厂出水中残留抗生素对受纳水体中水生生物的生态风险均较低(RQ0.1),但多种抗生素共存的混合长期风险仍需深入研究。     

城镇污水处理厂项目环境影响评价重点的研究

城镇污水处理厂作为一项环境保护工程,在发挥环境效益的同时,运行过程中排放的尾水、产生的恶臭和污泥等污染物对环境将产生不利影响。在进行污水处理厂项目环境影响评价时,应识别评价重点,目的是使环境影响预测和评价具有针对性,以发挥更大的环境效益。根据污水处理厂的工程特性,结合江门市江海污水处理厂工程环境影响评价的实践经验,提出污水处理厂环境影响评价应重点关注厂址环境合理性分析、污水处理工艺比选、尾水排放对水环境影响、恶臭对大气环境影响、污泥处置对环境影响等问题。     

含汞废水的净化方法

汞及其化合物有很高的毒性,水体中汞的极限浓度为0.005毫克/升,因此废水在排入水体之前,必须进行深度净化。在苏联和其他国家的专利文献中,对用各种物理和化学方法净化废水中汞化合物的报道很多。其中包括: 采用硫化钠、甲叉脲、含有磷化氢的乙炔气,2,3-二巯基丙烷磺酸盐、红胺酸铝、硫代硫酸钠和二硫代苯对二酸或者采用2,3-二巯基丙烷酸和硫代硫酸盐的碱溶液,而后用无机酸、硫脲和锆的粉沫等将汞转变为不溶解的汞。采用硫化铁,例如黄铁矿,或者冶金工业矿渣吸收汞,然后在400～500℃的情况下回收金属汞。也可在具有氯气情况下,用阴离子交换剂,或者用溶解度很小的硫化铜、硫化锌、硫化铅、硫化镍、     

传统活性污泥法污水处理厂脱氮除磷改造技术研究

随着受纳水体富营养化日益严重,污水处理厂尾水N、P排放成为迫切需要解决的问题.针对传统活性污泥工艺的实际情况,在脱氮除磷改造中,最大限度地利用原有处理构筑物,提出增加厌氧池或缺氧池以确保生物除磷或脱氮效果.改造采用基于两段A/O的生物处理工艺,工艺论证采用IWA使用的ASMs系列模型进行模拟,模型参数使用污水处理厂多年运行数据进行率定,模拟结论可信.此方法可广泛运用于污水处理厂的改造和设计中,特别是对污水处理运行诊断和实际运行节能减排过程优化具有优势.通过合理调整运行工艺参数,改造后污水处理厂尾水可达到<城镇污水处理厂污染物排放标准(GB 18918-2002)二级标准.     

污水处理厂用地情况分析及节地探讨

在新建以及旧有污水处理厂的提标改造中,节约用地将成为规划设计过程中的主要考虑因素。选取成都市及周边地区的10座污水处理厂,规模从1万~70万m3/d不等,通过进行现场调研及资料的收集分析,对污水处理厂规模、工艺情况与占地面积的关系进行分析,并提出设计中的优化措施与建议。     

发酵行业废水处理工艺恶臭处理技术及工程应用

针对某发酵废水处理厂恶臭气体的产生及组成特点,在比较分析常用除臭技术的基础上,结合国内外同类废水处理厂恶臭气体处理工程案例和本工程的特点,提出该厂各废水处理构筑物、厌氧罐溢流出水处和蛋白浓缩车间3类不同区域产生的恶臭气体分别采用组合式生物工艺、碱洗—次氯酸喷淋洗涤工艺和喷淋洗涤—电除雾—低温等离子组合工艺进行处理,并介绍了除臭工艺的选择及除臭系统的工程设计参数。工程运行结果表明:厂界硫化氢、氨和臭气浓度符合《恶臭污染物排放标准》(GB 14554-93)规定的恶臭污染物厂界标准的要求。     

周庄镇水污染控制规划实例

以保护古镇风貌和建筑为出发点进行周庄镇河道水体保护和水污染控制规划。按地形分 5个区进行污水收集 ,采用重力自流管和局部提升的污水输送方案 ,主干管埋在河道底部 ,窨井沿河道两侧交替分布 ,管网末端建造污水集中处理厂。     

郑州市王新庄污水处理厂改造工程设计

郑州王新庄污水处理厂原采用厌氧-好氧二级生化处理工艺,为满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)的排放要求,在充分利用原有处理设施的基础上,采用带前置缺氧段的A2/O工艺对原有设施进行改造,并新建部分污水和污泥处理设施.介绍了污水处理厂改造中的污水、污泥处理工艺,主要处理构筑物的设计参数,并对污水处理厂改造的实施过程提出了建议.     

Modifying ADM1 to include formation and emission of odourants.

A mathematical model that is based upon the ADM1 structure has been developed to describe the formation and emission of odourous compounds in anaerobic sludge digestion. Special emphasis is given to the general mechanisms for the formation of common odorous sulfur compounds that are found in anaerobic digesters: methyl mercaptan, dimethyl sulfide and hydrogen sulfide, as well as volatile fatty acids and ammonia. The model includes multiple-reaction stoichiometry, microbial growth kinetics and conventional material balances for an ideally mixed reactor. Simulations that were performed with the model revealed that changes in common operational parameters such as temperature, HRT and sludge metal content can dramatically impact upon the gas phase concentrations of odourants. Additional research is required to reduce uncertainty in the model formulation.     

Liquid-gas partitioning of selected volatile organic sulfur compounds in anaerobically digested sludges

The gas phase partitioning of volatile organic sulfur compounds (VOSCs) in anaerobic sludge digesters contributes to odors and can impact upon the suitability of biogases for use in alternative energy recovery technologies. In the present study, effective Henry's law coefficients (H') were estimated for methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) in both deionized water and deactivated digested sludge. It was found that the complex matrix of digested sludge did not significantly affect the partitioning of VOSCs. Therefore, partitioning of VOSCs in digesters could be represented by their partitioning in clean water. A regression model was developed for the linear relationship between ln H' and 1/T in the gas-water system. The H' values of MM, DMS, and DMDS were able to be calculated over a temperature range of 12-58 °C.     

Simulation of sulfide buildup in wastewater and atmosphere of sewer networks.

A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to--and a further development of--the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.     

Roles of methanogens on volatile organic sulfur compound production in anaerobically digested wastewater biosolids.

Land application of wastewater biosolids is both economical and beneficial to resource recycling. However, this environmentally friendly practice can be at risk due to odor complaints. Volatile organic sulfur compounds (VOSCs) including methanethiol, dimethyl sulfide, and dimethyl disulfide, have been identified as major contributors to biosolids odor. In this study, methanogens were shown to play a key role in removing VOSCs and reducing odors, and methane production was related to reduced VOSC production. Factors influencing the growth of methanogens such as the shear during dewatering and storage temperature showed a strong impact on net odor production. Examination of the microbial communities of both bacteria and archaea indicated a simplified archaeal community in biosolids, which is susceptible to environmental perturbations. Therefore, one possible odor control strategy is the preservation and enhancement of the methanogenic population during biosolids storage.     

Cryogenic trapping for determination of odor concentration.

The sensory testing method applied under Japanese law to measure odor concentration has a lower detection limit of 10 in the specified Odor Index. To measure odor below the limit, a condensing procedure using solid sorbents (Tenax-TA, Unicarbon B and Carbosieve SIII) has been developed and used in Japan. This procedure however cannot condense all odorous substances, and is specifically unsuited to hydrogen sulfide, methyl mercaptan, dimethyl sulfide, ammonia, and other typical odorous substances. In the present study, cryogenic trapping was tested to improve recovery rate. As water in sample air causes choking of the trap tube, vacant pre-columns to condense the water were connected to the Tenax-TA-packed column. The columns were chilled with liquid oxygen before passage of 100 L of sample air. The columns were then heated to 200 degrees C under passage of 50 mL/min of nitrogen carrier gas to desorb odors. The desorbed gases were captured in sampling bags made of polyethylene terephthalate film. The total volume of desorbed gases was approximately 1 L. The method showed good recovery rates for hydrogen sulfide, methyl mercaptan, dimethyl sulfide and ammonia, and was useful for determining low-level odor concentrations during measurement of odor in ambient air at various sites in Osaka City.     

Recent findings on sinks for sulfide in gravity sewer networks.

Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However, sulfide emission and thereby potential hydrogen sulfide buildup in the sewer atmosphere is of particular importance in sewers constructed with large diameter pipes, in sewers constructed with steep slopes and in sewers conveying low pH wastewater. Precipitation of metal sulfides is only important when the sulfide concentration in the wastewater is low; i.e. less than 1 g Sm(-3).     

Hydrogen sulfide emission in sewer networks: a two-phase modeling approach to the sulfur cycle.

Wherever transport of anaerobic wastewater occurs, potential problems associated with hydrogen sulfide in relation to odor nuisance, health risk and corrosion exist. Improved understanding of prediction of hydrogen sulfide emission into the sewer atmosphere is needed for better evaluation of such problems in sewer networks. A two-phase model for emission of hydrogen sulfide along stretches of gravity sewers is presented to estimate the occurrence of both sulfide in the water phase and hydrogen sulfide in the sewer atmosphere. The model takes into account air-water mass transfer of hydrogen sulfide and interactions with other processes in the sulfur cycle. Various emission scenarios are simulated to illustrate the release characteristics of hydrogen sulfide.     

Determination of nanogram level of VSCs using GC-SCD and an adsorption tube.

A quantitative analytical method was used for detection of low level of volatile sulfur compounds (VSCs) using GC with a sulfur chemiluminescence detector (SCD) in this study. A linear response over the range of 2-90 ngS injected was obtained with a good repeatability or reproducibility. Equimolar response for H2S, DMS, MeSH, and EtSH was obtained by use of SCD and the response of the SCD is nearly equimolar for different sulfur compounds. It was possible to quantify the total VSCs as well as individual VSC using one of the standard VSCs. VSC recovery was measured with respect to some storing methods. An adsorption tube packed with molecular sieve 5A showed almost perfect recovery for both H2S and dimethyl sulfide (DMS) during 6 days at a dark state below 2 degrees. Whereas, with a gas tight pyrex vial or tedlar bag, it was impossible to obtain the recovery of 50% after 6 days. It is strongly recommended to use the adsorption tube for determination of nanogram levels of volatile sulfur compounds and for storing and concentrating VSCs effectively with a minimum experimental error.     

A novel up-flow inner-cycle anoxic bioreactor (UIAB) system for the treatment of sulfide wastewater from purification of biogas

An up-flow inner-cycle anoxic bioreactor with a novel three phase separator was designed and implemented for the treatment of sulfide wastewater. The sulfide in wastewater could be converted to elemental sulfur by sulfide oxidizing bacteria, and recovered by simple precipitation. When the oxidation-reduction potential (ORP) was controlled at -100 mV, 91.3% of sulfide could be oxidized to elemental sulfur. To achieve high removal percentage of sulfide and conversion percentage of sulfur, the pH of influent should be controlled in the range from 7.0 to 8.0. The optimal desulfurization process was carried out at 400 mmol L(-1)d(-1) sulfide loading rate and 120 min hydraulic retention time (HRT). The removal percentage of sulfide was approximately 95.2% and elemental sulfur conversion percentage was above 90.3%. These results demonstrated that the novel up-flow in-cycle bioreactor had a potential value for the enhanced treatment of sulfide wastewater from biogas purification.