Chemistry: molecular biology and microbiology – Apparatus – Including measuring or testing
Reexamination Certificate
2000-02-17
2002-07-09
Beisner, William H. (Department: 1744)
Chemistry: molecular biology and microbiology
Apparatus
Including measuring or testing
C435S300100, C435S303200, C435S303300, C422S079000
Reexamination Certificate
active
06416994
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a measuring apparatus for measuring specific methanogenic activity of granular sludge used in an anaerobic wastewater processing method.
BACKGROUND TECHNOLOGY
As a known measuring apparatus for measuring specific methanogenic activity of sludge, there is that used in a method called as “the vessel method” as disclosed in the publication “Journal of water and Waste (in Japanese) Vol. 37, No. 7 (1995)”, which is as shown in FIG.
12
and
FIG. 13
, and description is made hereinafter for the apparatus. A plurality of narrow-mouthed bottles
62
, to each of which a gas conduit piping
61
is disconnectably connected, are placed in water in a thermostatic bath
63
with a stirring member
66
and a heater
67
installed in the thermostatic bath
63
, a tip of the gas conduit piping
61
is inserted in a washing gas bottle
68
filled with 1N, NaOH, this washing gas bottle
68
and a gas holder
69
are connected to each other with the gas conduit piping
61
, and a scale
72
is attached to the gas holder
69
.
An operating sequence when measuring specific methanogenic activity of sludge with the apparatus as described above is shown in an operation flow chart in
FIG. 13
, and in this flow chart,
(1) A first sludge to be measured is sampled,
(2) the sampled sludge and a reaction mixture are put in the narrow-mouthed bottle
62
placed in the thermostatic bath
63
, and is kept in the state for raising the anaerobic characteristics of the apparatus with the stirring member
66
and heater
67
being operated for 12 hours at 35° C.,
(3) A gas generated in the narrow-mouthed bottle
62
is guided through the gas conduit piping
61
into the washing gas bottle
68
filled with 1N, NaOH to remove CO
2
, and then
(4) the gas is kept for 6 to 8 hours in the gas holder
69
, and during this period up and down movement of the gas holder
69
is visually read with the scale
72
once for every 1 hour to determine specific methanogenic activity (slope) [gCOD], and finally
(5) gVSS of the sludge is measured for 24 hours.
Then based on the specific methanogenic activity (slope) and a quantity of sludge [gVSS], a quantity of methane gas formed per day [gCOD/gVSS/d] is computed according to a sequence similar to that according to the present invention as described hereinafter.
PROBLEMS TO BE SOLVED BY THE INVENTION
By the way, with the measuring apparatus as described above, gas phase replacement is not taken into account in the measurement of specific methanogenic activity as described above, and a long period of time is required for raising the anaerobic characteristics of the apparatus. Totally, 44 hours are required for sampling of the sludge, and during this period of time an operator is required to continuously monitor a gauge without leaving the measuring apparatus, which is a heavy work load to the operator. In addition, measurement values are visually read by the operator from the scale, so that the read values may be inaccurate, and further careful operations are required to keep the narrow-mouthed bottle without causing movement thereof. When measuring sludge with a low specific methanogenic activity, sometimes a NaOH aqueous solution may flow in the reverse direction from a gas holder to the narrow-mouthed bottle with the specific methanogenic activity computed manually by the operator, which requires complicated operations and makes it difficult to quickly compute the specific methanogenic activity or to determine whether measured values on the specific methanogenic activity are acceptable or not.
It is an object of the present invention to provide a specific methanogenic activity measuring apparatus, which can solve the problems in the conventional type of specific methanogenic activity measuring apparatus as described above, requires only a short period of time for raising the anaerobic characteristics, finishes all steps from sampling sludge up to measurement, and also which can automatically record a result of measurement without requiring an operator to stay near the measuring apparatus and continuously monitor the gauges, and resultantly, which does not give a large work load to the operator, nor requires the operator to pay minute attentions for statically keeping the reaction vessel, and further, in which the NaOH solution never flows in the reverse direction into the reaction vessel when measuring sludge with low specific methanogenic activity, the operator is not required to manually compute the specific methanogenic activity, the activity can quickly and easily be computed, and further determination can be made as to whether the measured specific methanogenic activity value is acceptable or not.
MEANS FOR SOLVING THE PROBLEMS
To achieve the objectives as described above, the invention provides a specific methanogenic activity measuring apparatus having a measuring means for measuring specific methanogenic activity of sludge in anaerobic wastewater or soil processing and a recording means, and the measuring apparatus has a pressure vessel with a cover removably attached thereto, a carbon dioxide gas absorbing container, and a thermostatic bath with the pressure vessel removable placed therein as the measuring means, in which a pressure transducer based on the pressure-electricity converting system connected to the recorder is attached to the cover, a supporting member for the carbon dioxide gas absorbing container is attached to an external bottom surface of the carbon dioxide gas absorbing container, a gas piping for venturation penetrating an internal surface of the container, and further a gas piping with a valve for gas phase replacement to a cover of the pressure vessel respectively, and in the invention, a magnetic stirrer is attached to the internal bottom surface of the pressure vessel.
The inventions provide the advantages that the time required for raising the anaerobic characteristics of the apparatus is short, all steps from sampling sludge up to final measurement can be finished within a short period of time, also the apparatus itself can automatically record a result of measurement, an operator is not required to stay near the apparatus for continuously monitoring the gauges, thus the work load of the operator is reduced, and further, an accurate result of measurement can be obtained, minute attentions are not required for statically keeping the reaction vessel, and the NaOH solution never flows in the reverse direction into the reaction vessel when measuring sludge with a low specific methanogenic activity.
The invention also provides a screen display unit having a computing section for automatically computing a quantity of methane formed per day [gCOD/gVSS/d] from information on pressure detected by a pressure transducer based on a pressure-electricity converting system in the measuring means as a recording means and a display section for displaying a computed value processed by the computing section; wherein the computing section measures changes in pressure for a specified period of time for determination according to a pressure signal from the pressure transducer in the measuring means, converts the slope of the pressure change to a historical change in a quantity of formed gas and also to a unit [gCOD/h] which can be expressed as a load corresponding to a methane gas forming rate per hour x[ml], computes a methane gas forming rate per day for one unit volume of sludge by dividing the converted methane gas forming rate x[gCOD/h] by a total volume of sludge [gVSS] used for measurement; the computing section has an A/D convertor for converting a pressure signal from the pressure transducer in the measuring means to a digital signal, a determination time counter for manually setting a determination time therein and numerically displaying a determination time, a gVSS counter for manually setting a gVSS of sludge therein and numerically displaying the gVSS of the sludge, and a control section for computing a methane forming
Harada Yoshmitsu
Imabayashi Seiji
Kitagawa Yasushi
Uruga Akira
Asahi Breweries Ltd.
Beisner William H.
Flynn ,Thiel, Boutell & Tanis, P.C.
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