浅析污水厂污泥厌氧消化成分及其变化过程

阐述了污水处理厂污泥厌氧消化过程中各种成分的变化过程及反应参数对其的影响.     

Microbiological and chemical quality of sludges from domestic wastewater plants

Digested sludge samples from domestic wastewater treatment plants located in Northern Italy were tested as far as the presence of viruses (enteric viruses and coliphages), bacteria (faecal coliforms, salmonella) and helminth eggs is concerned. Heavy metals were also analysed. Escherichia coli bacteriophages and faecal coliforms were isolated from all samples, while salmonellae and helminth eggs were isolated only from four and three out of 27 total samples, respectively. The 66% of sludge samples, 46 and 82% of aerobic and anaerobic digested sludges respectively, showed the presence of enteric viruses (enteroviruses and reoviruses). The virus concentrations ranged from 0.6 to 123 MPNCU/g. Results of this study suggest that significant concentrations of pathogens such as enteric viruses can be present in digested sludge, which showed compliance with Italian legislation. As suggested by other authors, there is the need for surveillance and reference indications both in EU (European Union) and Italian regulations concerning the use of sludge in agriculture.     

Viral elution and concentration method for detection of influenza A viruses in mud by real-time RT-PCR

The role of environmental reservoirs in avian influenza virus (AIV) transmission has been investigated during AIV-associated outbreaks. To date, no method has been defined for detection of AIV from mud samples. A procedure using elution and polyethylene glycol (PEG) concentration steps was designed to detect AIV by RT-PCR from 42 g of raw mud, corresponding to 30 g of the solid fraction of mud. RNA was recovered with MagMAX AI/ND Viral RNA Isolation kit (Ambion, Austin, TX). Three elution buffers were studied and viral recoveries higher than 29% were yielded by elution with a 10% beef extract solution (pH 7). The overall method showed that, under some conditions, virus was not detectable in PEG samples, whereas viruses were detected in the elution fractions. PCR curves were improved significantly by running the amplification reaction with a mixture containing a PCR additive for inhibitor removal, such as T4 gene 32 protein (Gp32), although PCR inhibitors from mud were removed partially from PEG samples. A theoretical detection threshold of 5 × 10⁵ RNA copies of H5N1 virus per 30 g of solid mud could be obtained by elution. The overall method has proved successful for detecting H5N1 virus contamination of mud specimens collected during outbreak investigations of avian influenza in Cambodia.     

Tuberculosis and other chronic morbidity profile of sewage workers of Delhi

Background

Sewage management is hazardous due to chronic exposure to chemical gases, bioaerosols and micro-organisms through inhalation; accidental oral intake and penetration through skin or mucous membranes through injuries or breech in personal protective equipment. While there has been some research on isolated infections and multisystem symptom profiling of sewage workers, there is little research on the burden of chronic illnesses like Tuberculosis and Non Communicable Diseases (NCDs).

Heavy metals and PAHs in sewage sludge from twelve wastewater treatment plants in Zhejiang province

Objective To investigate the heavy metals （HMs） and polycyclic aromatic hydrocarbons （PAHs） in sludge of twelve wastewater treatment plants （WWTPs） in Zhejiang province of China, and to assess their potential for land application. Methods Sludge was collected from 12 WWTPs within the province. GC-MS and AAS were used to measure PAHs and HMs contents in sludge. Results Concentrations of HMs in most of the sludge samples were below the regulatory limits for the sludge to be used in agriculture in China with the exception of Zn in 2 sludge samples and Cd in 1 sample. All 16 PAHs, targeted by the USEPA agency, were found in the sludge from the twelve plants with a total concentration ranging from 33.73 mg kg^-1 to 82.58 mg kg^-1 （dry weight, d.w.）. The levels of Σ9 PAHs varied from 13.87 mg kg^-1 to 61.86 mg kg^-1 （d.w.） in the sludge, far exceeding the limitation value recommended by the Europe Union. The concentration and composition of PAHs in sewage sludge varied and depended mainly on the quantity and type of industrial wastewater accepted by the WWTPs. A significant relationship between the proportion of industrial wastewater received by WWTPs and the total content of 16 PAHs in the sludge was observed. Conclusion PAHs have become one of the primary pollutants in sludge of Zhejiang WWTPs instead of HMs. It is, therefore, essential to reduce the contents of PAHs before the sludge can be used in agriculture through proper treatment.     

Cirrhosis: A New, But Expected Cause of Biliary Sludge

BackgroundlAims: Biliary sludge is increasingly recognized as a natural stage in gallstone formation. Logically, cirrhosis, a well-documented cause of black pigment cholelithiasis, should be another condition predisposing to the development of sludge. The aim of this study was to assess the prevalence of biliary sludge in an unselected population and to test the hypothesis that cirrhosis could be one of the causes of sludge. Methods: We reviewed the clinical findings and ultrasonograms of 2138 patients, hospitalized or not, consecutively seen in our department between January 1993 and December 1994. Sonograms showing biliary sludge mixed with stones were excluded. Three hundred and eighty-eight of the 2138 were cirrhotic patients. Results: The overall prevalence of biliary sludge was 4%. Sludge was found in 44 of 388 (11%) of the cirrhotic patients (alcoholism, n = 39; chronic viral B hepatitis, n = 3; hemochromatosis, n = 1; and cryptogenic, n = l), compared with 42 of 1750 (2%) noncir-rhotic patients (p < 0.000001). Thirteen cirrhotic patients received intravenous alimentation for 2 to 17 days, 8 were given somatostatin for variceal bleeding, and 7 have previously had 1 to 5 sessions of endoscopic sclerotherapy of esophageal varices with polidocanol. Conclusions: This study convincingly demonstrates that cirrhosis must be added to the growing list of conditions associated with biliary sludge.     

Application of toxicity identification evaluation procedures on wastewaters and sludge from a municipal sewage treatment works with industrial inputs

A comparison of influent and effluent wastewater toxicities to Daphnia magna was undertaken to determine the most representative aqueous fraction for future toxicity identification evaluation (TIE) studies. Wastewater samples originated from a wastewater treatment plant which receives mainly domestic wastewater and industrial effluents. The TIE results reveal that the key toxicant contained in the influent was 2-propylbezaldehyde oxime. Results suggest that greater attention needs to be given to the receiving influent containing 2-propylbezaldehyde oxime to avoid damaging the bacterial populations in the primary activated sludge process. In addition, in order to evaluate the applicability of the reuse of activated sludge as a fertilizer in agriculture, TIE studies were also performed on water extracts from surplus sludge.     

原位肝移植术后胆道充盈缺损性胆系并发症的研究

目的探讨原位肝移植术后胆道充盈缺损性胆系并发症的病因及处理。方法回顾性分析1999年2月至2005年12月完成的325例原位肝移植的临床资料。结果术后发生胆泥3例，胆总管结石10例，胆管铸型综合征6例。MRCP或ERCP诊断准确率为100％，B超诊断准确率为78．9％。11例通过内镜介入取出结石、胆泥或铸型物，手术取石4例，再次肝移植手术4例。结论肝移植术后发生胆道充盈缺损性胆系并发症可能与缺血-灌注损伤、胆道缺血、排斥反应和CMV感染等因素有关。胆道成像技术有助于诊断及鉴别诊断。内镜治疗是首选方法，手术应在介入治疗无效后考虑。     

添加剂对污泥填埋渗滤液性质影响研究

将城市污水处理厂污泥分别与生石灰、粉煤灰、黏土按质量2：1混合后填埋，研究各填埋柱渗滤液的pH、SS、CODcr、BOD5、总氮、氨氮、总磷、Na^ 、K^ 、Mg^2 、Ca^2 的变化规律。结果表明添加剂能够显著改变污泥的物理性质，而且渗滤液性质及污泥中污染物迁移转化行为也与添加剂有密切关系。     

自来水厂污泥的表征及其垃圾覆盖土可行性研究

对自来水厂污泥进行了较系统的试验研究,如浸出毒性实验、剪切试验、重金属含量的检测等,以及作为垃圾覆盖土的可行性。研究结果表明,自来水厂污泥在1～2kg／cm^3压力作用下,含水率从61．3％减少到46．3％,渗透系数达到10^-7cm／s,无渗透毒性。用该污泥作垃圾填埋场覆盖土的边坡稳定性能较好,基本上满足作为覆盖土的技术要求,使用后不会给垃圾渗滤液的处理增加负担。因此,以自来水厂污泥作为生活垃圾填埋场覆盖土。可同时解决平原型填埋场缺土和污泥的最终出路问题。