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Method and apparatus for monitoring sewage treatment efficiency and determining sewage sources
V
New Patents
4554077 METHOD AND APPARATUS FOR MONITORING SEWAGE TREATMENT EFFICIENCY AND DETERMINING SEWAGE SOURCES Leslie Brown, James Braven, Michael M Rhead, Plymouth, United Kingdom assigned to Devon County Council A method of tracing sewage effluent is described in which samples of fluid flows are subjected to high performance liquid chromatography with respective elution systems capable of eluting different selected compounds therefrom, and the concentration of each compound in the sample is determined spectroscopically. The method is used to determine sewage flow paths in natural water bodies, such as rivers, to check for contamination by sewage, to determine possible sewage sources, the detection of uric acid, for example, being indicative of a human source; and to monitor the effluent from sewage treatment plants. A monitoring system for sewage treatment works is also described in which bromophenol blue is added to the sewage influent to the biodegradation stage as a dilution indicator and the changes in the bromophenol blue concentration and in the concentration of a biodegradable sewage component, such as uric acid, are monitored throughout the stage to give an indication of the progress of the biodegradation reaction; this information is used in controlling the operation of the plant to maximize its efficiency.
4555629 METHOD AND APPARATUS FOR DETERMINATION OF SAMPLE HOMOGENEITY IN SCINTILLATION COUNTING Leroy Everett, Stanley J DeFilippis assigned to Packard Instrument Company Inc A method for ascertaining radiochemical homogeneity in a liquid scintillation sample reliably identifies inaccurate geometries is disclosed so that meaningful activity counts can be determined. The novel method involves measuring the activity level of a set of homogeneous quench standard to obtain quench indicating parameter, or the Spectral Index of the External standard (SIE). The endpoint of each standard sample is computed allowing the formation of a table so
that a calibration curve for each radionuclide of interest can be computed. The activity level of the unknown sample is then measured and the SIE determined so that an endpoint can be calculated. Finally, the theoretical endpoint obtained from a calibration curve is compared to the computed endpoint; if the computed endpoint of the sample deviates by more than 4% for tritium and 5% for higher energy radionuclides from the theoretical endpoint, the sample is considered to be nonhomogeneous or heterogeneous. An external standard-type liquid scintillation counting system is disclosed which automatically determines sample homogeneity, and it includes a microprocessor in its control system. The steps of the present invention and incorporated into the programmed steps for the microprocessor such that nonhomogeneous or heterogeneous samples are automatically identified on the readout of the system for an investigator.
4555634 OPTICAL SMOKE DETECTOR WITH CONTAMINATION DETECTION CIRCUITRY Jurg Muggli, Heinz Guttinger, Zoltan Horvath, Mswitzerlana assigned to Cerberus AG A smoke detector is disclosed having a radiation source operated in a pulsed mode. Externally of a direct radiation region of the radiation source there is arranged a radiation receiver which, in the presence of smoke or other particles emanating from a combustion process and located in the radiation region, is impinged by scattered radiation and delivers an output signal to an evaluation circuit. The evaluation circuit contains switching elements which, when the number of source output signals or pulses exceeds a predetermined threshold value for the number of source output pulses, delivers an alarm signal. Near to the radiation receiver there is arranged a reference cell in the direct radiation beam of the radiation source, this reference cell controlling the emission of radiation by the radiation source. Further, there is provided circuitry which, in the presence of a slow change in the amplitude of the receiver output pulse, adjusts an amplitude threshold value set for the amplitude of the receiver output pulse at a rate corresponding to a time-constant of more than one minute. Consequently, there is obtained an output signal of the radiation receiver which is dependent upon the smoke density and which is independent of the contamination or soiling of the smoke detector.
New Patents
4554077 METHOD AND APPARATUS FOR MONITORING SEWAGE TREATMENT EFFICIENCY AND DETERMINING SEWAGE SOURCES Leslie Brown, James Braven, Michael M Rhead, Plymouth, United Kingdom assigned to Devon County Council A method of tracing sewage effluent is described in which samples of fluid flows are subjected to high performance liquid chromatography with respective elution systems capable of eluting different selected compounds therefrom, and the concentration of each compound in the sample is determined spectroscopically. The method is used to determine sewage flow paths in natural water bodies, such as rivers, to check for contamination by sewage, to determine possible sewage sources, the detection of uric acid, for example, being indicative of a human source; and to monitor the effluent from sewage treatment plants. A monitoring system for sewage treatment works is also described in which bromophenol blue is added to the sewage influent to the biodegradation stage as a dilution indicator and the changes in the bromophenol blue concentration and in the concentration of a biodegradable sewage component, such as uric acid, are monitored throughout the stage to give an indication of the progress of the biodegradation reaction; this information is used in controlling the operation of the plant to maximize its efficiency.
4555629 METHOD AND APPARATUS FOR DETERMINATION OF SAMPLE HOMOGENEITY IN SCINTILLATION COUNTING Leroy Everett, Stanley J DeFilippis assigned to Packard Instrument Company Inc A method for ascertaining radiochemical homogeneity in a liquid scintillation sample reliably identifies inaccurate geometries is disclosed so that meaningful activity counts can be determined. The novel method involves measuring the activity level of a set of homogeneous quench standard to obtain quench indicating parameter, or the Spectral Index of the External standard (SIE). The endpoint of each standard sample is computed allowing the formation of a table so
that a calibration curve for each radionuclide of interest can be computed. The activity level of the unknown sample is then measured and the SIE determined so that an endpoint can be calculated. Finally, the theoretical endpoint obtained from a calibration curve is compared to the computed endpoint; if the computed endpoint of the sample deviates by more than 4% for tritium and 5% for higher energy radionuclides from the theoretical endpoint, the sample is considered to be nonhomogeneous or heterogeneous. An external standard-type liquid scintillation counting system is disclosed which automatically determines sample homogeneity, and it includes a microprocessor in its control system. The steps of the present invention and incorporated into the programmed steps for the microprocessor such that nonhomogeneous or heterogeneous samples are automatically identified on the readout of the system for an investigator.
4555634 OPTICAL SMOKE DETECTOR WITH CONTAMINATION DETECTION CIRCUITRY Jurg Muggli, Heinz Guttinger, Zoltan Horvath, Mswitzerlana assigned to Cerberus AG A smoke detector is disclosed having a radiation source operated in a pulsed mode. Externally of a direct radiation region of the radiation source there is arranged a radiation receiver which, in the presence of smoke or other particles emanating from a combustion process and located in the radiation region, is impinged by scattered radiation and delivers an output signal to an evaluation circuit. The evaluation circuit contains switching elements which, when the number of source output signals or pulses exceeds a predetermined threshold value for the number of source output pulses, delivers an alarm signal. Near to the radiation receiver there is arranged a reference cell in the direct radiation beam of the radiation source, this reference cell controlling the emission of radiation by the radiation source. Further, there is provided circuitry which, in the presence of a slow change in the amplitude of the receiver output pulse, adjusts an amplitude threshold value set for the amplitude of the receiver output pulse at a rate corresponding to a time-constant of more than one minute. Consequently, there is obtained an output signal of the radiation receiver which is dependent upon the smoke density and which is independent of the contamination or soiling of the smoke detector.