Sludge Thickening Prior to Anaerobic Digestion

1984 ◽  
Vol 16 (12) ◽  
pp. 419-432 ◽  
Author(s):  
H Kapp
Keyword(s):  
Anaerobic Digestion ◽  
Federal Republic ◽  
Gas Production ◽  
Operating Parameters ◽  
Federal Republic Of Germany ◽  
Digestion Time ◽  
Sludge Treatment ◽  
Retention Period ◽  
Solids Content ◽  
Sludge Thickening

In the Federal Republic of Germany the average solids content in digested sludges is about 3%. Increasing the solids content to 6-8% by pre-dewatering would mean that the sludge volume would be reduced to 40-50%. For the same retention period the volume of new digesters will be reduced and the necessary energy for heating decreased. Overloaded sludge treatment plants can be upgraded, as digestion time becomes longer and gas production increases. As pre-dewatering machines, first of all decanting centrifuges and screens can be recommended. The addition of coagulant aids is necessary to some extent. In the case of two practical examples, the operating parameters of raw sludge thickening as well as the economic advantages of the operating procedure are shown.

Solids Concentrations in a Treatment Plant Effluent

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2543-2546
Author(s):  
M. Defrain ◽  
F. Schmidt
Keyword(s):  
Waste Water ◽  
Activated Sludge ◽  
Federal Republic ◽  
Treatment Plant ◽  
Analysis Procedure ◽  
Process Water ◽  
Federal Republic Of Germany ◽  
Output Variable ◽  
Sludge Treatment ◽  
Sewerage Network

In the calculations customarily used to dimension nitrification and denitrification plants in the Federal Republic of Germany, solids in the influent of the biological stage represent a significant output variable. Numerous modified methods based on nationally and internationally standardized analysis procedures are available to determine solids concentrations in waste-water. Tests showed that different values are measured depending on the method of analysis employed. Harmonization of the analysis procedure is advisable to ensure comparable conditions for the calculation of activated sludge tank volumes. The solids reaching a treatment plant originate from two main sources. Filterable materials are passed to the treatment plant via the preceding sewerage network with its industrial and commercial users, but are also carried by process water from sludge treatment. The influence of process water on wastewater composition is illustrated by reference to the Wuppertal-Buchenhofen treatment plant.

Alkaline treatment of high-solids sludge and its application to anaerobic digestion

2014 ◽  
Vol 71 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Chenchen Li ◽  
Huan Li ◽  
Yuyao Zhang
Keyword(s):  
Anaerobic Digestion ◽  
Treatment Duration ◽  
Alkaline Treatment ◽  
Sludge Reduction ◽  
High Solids ◽  
Optimum Conditions ◽  
Digestion Time ◽  
Biogas Yield ◽  
New Process ◽  
Sludge Thickening

High-solids anaerobic digestion is a promising new process for sludge reduction and bioenergy recovery, requiring smaller digestion tanks and less energy for heating, but a longer digestion time, than traditional low-solids anaerobic digestion. To accelerate this process, alkaline sludge disintegration was tested as a pretreatment method for anaerobic digestion of high-solids sludge. The results showed that alkaline treatment effectively disintegrated both low-solids sludge and high-solids sludge, and treatment duration of 30 min was the most efficient. The relation between sludge disintegration degree and NaOH dose can be described by a transmutative power function model. At NaOH dose lower than 0.2 mol/L, sludge disintegration degree remained virtually unchanged when sludge total solids (TS) content increased from 2.0 to 11.0%, and decreased only slightly when sludge TS increased to 14.2%. Although high-solids sludge required a slightly higher molarity of NaOH to reach the same disintegration level of low-solids sludge, the required mass of NaOH actually decreased due to sludge thickening. From the view of NaOH consumption, sludge TS of 8–12% and a NaOH dose of 0.05 mol/L were optimum conditions for alkaline pretreatment, which resulted in a slight increase in accumulative biogas yield, but a decrease by 24–29% in digestion time during the subsequent anaerobic digestion.

Professional Qualification of German Physicians in Medical Informatics

1994 ◽  
Vol 33 (03) ◽  
pp. 312-314 ◽  
Author(s):  
J. Michaelis
Keyword(s):  
Medical Education ◽  
Clinical Practice ◽  
Federal Republic ◽  
Medical Informatics ◽  
Professional Training ◽  
Federal Republic Of Germany ◽  
Professional Qualification ◽  
Medical Degree ◽  
Formal Program ◽  
Medical Domain

Abstract:In addition to the medical education in the Federal Republic of Germany which includes a compulsory Medical Informatics course there exists a formal program for professional qualification of physicians in Medical Informatics. After two years of clinical practice and 1.5 years of professional training at an authorized institution, a physician may receive in addition to the medical degree a “supplement Medical Informatics”. The qualification requirements are described in detail. Physicians with the additional Medical Informatics qualification perform responsible tasks in their medical domain and serve as partners for fully specialized Medical Informatics ex-’ perts in the solution of practical Medical Informatics problems. The formal qualification is available for more than 10 years, has become increasingly attractive, and is expected to grow with respect to future Medical Informatics developments.

Studies on Thalidomide as a Cause of Congenital Malformations

1963 ◽  
Vol 02 (02) ◽  
pp. 49-51 ◽  
Author(s):  
K. Knapp ◽  
W. Lenz
Keyword(s):  
Federal Republic ◽  
Congenital Malformations ◽  
Chemical Substance ◽  
Federal Republic Of Germany ◽  
Virus Diseases ◽  
Many Sources

SummaryIn 1961 an increase in certain congenital malformations was noticed in various parts of the Federal Republic of Germany. From the outset, it seemed very probable that a single cause was responsible, since, although these malformations varied, they appeared to belong to one and the same syndrome. For general reasons, such causes as radioactivity, contraceptives, attempted abortions or virus diseases did not provide an acceptable explanation. The epidemiology was, however, suggestive of some chemical substance taken orally.After thalidomide had been indicated in several histories, suspicion of that drug was aroused and, within one week, intake of it could be proved or was found to be very likely in 17 out of 20 cases, while in the remaining cases it could not be excluded. Though this first result was highly significant, we were at first reluctant to incriminate thalidomide definitely, because there was still some doubt about the reliability of the histories. But within a few weeks, the thalidomide aetiology received support from many sources. Specific studies on limited material are sometimes superior to extensive, broadly planned investigations.

Market Analysis of the Per Capita Consumption of Smoke Condensate and Nicotine in the Federal Republic of Germany Between 1961 – 1970/Trendanalysen zum Problem des Verbrauches an Nikotin und Rauchkondensat in der Bundesrepublik Deutschland für die Jahre 1961-1970

1971 ◽  
Vol 6 (1) ◽  
Author(s):  
J. Misfeld ◽  
J. Timm
Keyword(s):  
Federal Republic ◽  
Market Analysis ◽  
Cigarette Consumption ◽  
Capita Consumption ◽  
Federal Republic Of Germany ◽  
Research Results ◽  
Bundesrepublik Deutschland ◽  
Per Capita ◽  
Per Capita Consumption

AbstractOn the basis of numerous research results and data on the development of nicotine and condensate contents of German cigarettes, of their respective shares in the market, the smoked length of cigarettes, and of the pro capita consumption of cigarettes in the Federal Republic of Germany, an estimate has been prepared on the yearly pro capita consumption of smoke condensate and nicotine in the Federal Republic covering the years 1961-1970. The values for 1961 amount to 40.2 g of smoke condensate (crude) and to 2.04 g of nicotine. The values for 1970 are found to be only 29.4 g and 1.63 g respectively. That means that the consumption of smoke condensate and nicotine in the Federal Republic has decreased during the last ten years. The share of smokers having remained almost the same, the consumption of smoke condensate and nicotine per smoker is, as well, found to have decreased by about 27 % and 20 % respectively during the years between 1961 and 1970 despite an increased cigarette consumption.

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