CN102707075A

CN102707075A - Laboratory automatic biochemical oxygen demand BOD5 detector and automatic measurement method

Info

Publication number: CN102707075A
Application number: CN2011100739772A
Authority: CN
Inventors: 王根忠; 丁秋兰
Original assignee: JIANGFEN ELECTRICAL ANALYZERS CO Ltd JIANGSU
Current assignee: JIANGFEN ELECTRICAL ANALYZERS CO Ltd JIANGSU
Priority date: 2011-03-26
Filing date: 2011-03-26
Publication date: 2012-10-03
Anticipated expiration: 2031-03-26
Also published as: CN102707075B

Abstract

A laboratory automatic BOD5 detector is mainly composed of a hardware part and a software part. The hardware part is composed of a computer, a computer communication interface, a multi-way solenoid valve pump, signal acquisition and processing units, culture flasks, pipelines and the like; The software can be applied on windows platform, and various parameters of experiments are divided into a type of system default and a type of free input by users. The detector can realize automatic injection, automatic drainage, automatic cleaning, and automatic saving and printing of data and curves of experimental results for water samples. The detector has the advantages that the tedious work of experimenters is greatly reduced, the operation is relatively convenient and simple, and the experimental data is relatively accurate and reliable.

Description

Laboratory automatic biochemical oxygen utilization BOD5 analyzer and automatic assay method

Technical field

The present invention relates to the field of the measurement of bod BOD5, in particular for the automatic field of measurement of breadboard BOD5.

Background technology

Biochemical oxygen demand (BOD) is called for short bod, often is designated as BOD, be meant during certain in, microorganism decompose in the certain volume water some can oxidized material, the quantity of the free dissolved oxygen that particularly organic substance consumed.It is an overall target of organic contaminant content in the reflection water.If carry out the time of bio-oxidation and be just being called in five days five-day BOD (BOD5).BOD5 is meant water sample to be measured under aerobic conditions, and constant temperature culture is in the time of five days in incubator for sample, and the quantity of the free dissolved oxygen that aerobic microbiological oxygenolysis unit bodies ponding organism or inorganics are consumed is represented with mg/L, is designated as BOD5.

The measuring principle of water sample BOD5 is: water sample to be measured is poured in the culture flask by the good certain volume of pre-estimating of measurement range amount, and cultivation temperature is controlled at 20 ± 1 ℃, and the microorganism that maintains in the sufficient dissolved oxygen water supply appearance carries out biochemical reaction.Organism in the sample is transformed into nitrogen, carbon, sulfur oxide through biological oxidation.In this course; The soda ash that unique carbon dioxide that can from water sample, overflow is placed in the culture flask absorbs; And this microbial biochemical reaction is in an airtight environment, to carry out; Therefore, the air pressure in the culture flask will reduce, the amount of the dissolved oxygen DO that the amount that reduces just consumes corresponding to Institute of Micro-biology.Through theory and experiment confirm: the BOD5 value of water sample is directly proportional with the degree that air pressure in the bottle reduces.Through measuring the value that reduces of culture flask air pressure, we just can obtain water sample BOD5 value.

Usually at the laboratory BOD5 analyzer that is commercially available, being manual operations is main experimental apparatus.The sampling of instrument still is that artificial graduated cylinder is measured, and the software section of instrument is still with written program under the dos operating system.It is very much inconvenience that the experimenter operates, and the accuracy of experimental data and processing power can not satisfy the everyday environmental monitoring requirement of the water sample of growth far away.

Summary of the invention

The invention provides the automatic BOD5 analyzer in a kind of laboratory, it mainly is made up of the hardware and software two large divisions.Hardware is mainly by computer, compunlcation interface, multichannel solenoid valve pump, signal acquisition process unit, culture flask, compositions such as pipeline; Software is application software original under the platform of windows, and the various parameters of experiment are divided for by system is silent and known and the user freely imports two kinds of forms.This analyzer can realize testing water sample auto injection, release automatically, clean automatically; The automatic preservation and the printing of the data of experimental result and curve; Alleviated experimenter's complicated work thus greatly, and more convenient operation is simple and direct, experimental data more accurately and reliably.

Description of drawings

Fig. 1 is a laboratory automatic BOD5 analyzer hardware block diagram; Selected pipeline path when wherein, Fig. 1 only marks mensuration appearance 1 mensuration is as an example.

Hardware configuration mainly is made up of following parts:

1, inoculation water reagent bottle, 2, mark liquid reagent bottle, 3, the water sample culture flask, 4, multichannel solenoid valve pump; 5, computer data is handled, and shows to print 6, water sample places beaker, 7, signal processing unit; 8, little differential pressure sensor, 9, the alkali absorption cell, 10, drainage valve.

Fig. 2 is a titer configuration block diagram;

Fig. 3 is that instrumentation program is carried out block diagram;

Fig. 4 is an instrument terminal display interface synoptic diagram.

Embodiment

For the accuracy of inspection apparatus, need at first carry out the titer test of (being called for short mark liquid) usually, also be referred to as instrument is carried out the process that chemistry is demarcated.The mark liquid that adopts among the present invention is to adopt the sanitary sewage supernatant as the postvaccinal Portugal of inoculation water-paddy mark liquid, and its preparation sees also Fig. 2.

Mark liquid for preparing in advance and inoculation water are placed reagent bottle respectively, and be placed on all test water samples and culture flask assigned position and connect solution connecting pipeline (referring to Fig. 1).Wherein:

(1) the alkali absorption cell of culture flask internal upper part is vessel of depositing soda ash (or liquid), and the gasket seal as culture flask uses again.The hole that the alkali absorption cell has the number place to communicate with the culture flask air, when the microorganism in the water sample carried out biochemical reaction, the carbon dioxide of emitting got into the alkali absorption cell through this hole and is absorbed, thereby formed the little negative pressure in the culture flask.

(2) culture flask is positioned at the lowermost end of culture flask with the extraneous interface tube that communicates, but has guaranteed the water sample waste liquid emptying emptying of releasing.The binding pipeline of bleeder valve and culture flask is short as far as possible.Piping material be can not oxygen flow material, for example PVC plastic pipeline etc. can not use macromolecular oxygen flow pipelines such as silicon rubber.

(3) pressure that determines through micro-pressure sensor reduces value and sends to computer through signal processing unit.

Start Application of B OD program software, the mark liquid and the inoculation water of certain volume is driven into the test of carrying out standard model in the pre-designed culture flask through multichannel solenoid valve pump.According to the common practise of this area, if the BOD5 numerical value of measuring this mark liquid between the 180-230mg/L scope, this analyzer is accurately believable so.

Next, just can carry out the test of actual water sample.Equally, multichannel solenoid valve pump is squeezed into each test specimens respectively in the different culture bottle under the control of program and is tested, until whole real the end and the printing experimental data.Control procedure sees Fig. 3 for details.

Test process for actual water sample need to prove:

(1) set the BOD5 range after, whether select dilute sample according to this range and actual sample.If the organic contaminant in the sample of selecting is dense, measure after then suitably diluting certain multiple, to avoid exceeding the setting range.

(2) adjusting of water sample PH is in order to provide one to be suitable for the environment that microorganism carries out biochemical reaction, and peracid or the environment of crossing alkali all are unfavorable for the biochemical reaction of microorganism, and general pH value should remain on about 7.6.

(3) setting of inoculum concentration is meant, according to the situation of actual sample, if the content of microorganisms in the sample is lower, can suitably adds said inoculation water and inoculate, and scope is between 0%-10%.Inoculation water is the supernatant of 20 ℃ of following sanitary sewages.

(4) A, B, C, the concrete preparation of four kinds of solution of D is referring to Fig. 2.

After test is accomplished, drainage valve will test water sample after accomplishing and released in the waste collection bucket, and repeat automatically distilled water flushing culture flask 3 times is waited until experiment use next time through multichannel solenoid valve pump.The computer interface of experimental result is seen Fig. 4.

Claims

1. laboratory automatic biochemical oxygen utilization BOD5 analyzer, the two large divisions constitutes by hardware and software, and hardware comprises computer; The compunlcation interface is contained with the inoculation water reagent bottle of inoculating water, is contained with the mark liquid reagent bottle of titer; Be contained with the water sample beaker of actual water sample, the water sample culture flask; Software can be used under the windows platform; The various parameters of experiment divides for by system silent know with the user freely import two kinds of forms, through software control realize testing water sample auto injection, release automatically, data and the automatic preservation of curve and the printing of cleaning and experimental result automatically; It is characterized in that: also comprise the pipeline that is used to connect mentioned reagent bottle, culture flask, beaker; Be used to control, select the multichannel solenoid valve pump of each pipeline solution inflow; And the elementary errors pressure sensor, be used for measuring reducing value and after signal processor processes, sending to computer of water sample culture flask pressure.

2. BOD5 analyzer according to claim 1 is characterized in that: water sample culture flask internal upper part is provided with an alkali absorption cell in order to absorb the carbon dioxide of emitting when microorganism carries out biochemical reaction, when measuring, and the sealing of water sample culture flask.

3. BOD5 analyzer according to claim 2 is characterized in that: the alkali absorption cell also uses as the gasket seal of culture flask.

4. BOD5 analyzer according to claim 1; It is characterized in that: the interface tube that culture flask communicates with the external world is positioned at the lowermost end of culture flask; With the water sample waste liquid emptying emptying that guarantees to release, releasing of waste liquid controlled through bleeder valve, and the binding pipeline of said bleeder valve and culture flask is short as far as possible.

5. BOD5 analyzer according to claim 1 is characterized in that: piping material adopts the not material of oxygen flow.

6. realize measuring automatically the method for bod BOD5 comprising step through software control for one kind:

(1) data such as input sample name, experimental period, experiment people;

(2) actual water sample of measuring according to need is through the pipe passage of an actual water sample of multichannel solenoid valve selection;

(3) range of setting BOD5, whether contaminated degree decision dilutes this actual water sample according to the organism of range and actual water sample;

(4) regulate the pH value of this water sample, obtain to be suitable for the environment that microorganism carries out biochemical action;

(5) add inoculation water, the scope of inoculation water is between 0%-10%;

(6) add A, B, C; Four kinds of solution of D, addition is 1ml/L, wherein; A solution is damping fluid, and formulated by 1.7g NH4CL, 21.75g K2HPO4,8.5g KH2PO4,33.4g sodium hydrogen phosphate Na2HPO47H2O, 1L distilled water, B solution is MgSO4 solution; Formulated by 22.5g MgSO47H2O and 1L distilled water, C solution is CaCl2 solution, and is formulated by 27.5g lime chloride CaCl2 and 1L distilled water; D solution is ferric trichloride FeCl3 solution, and is formulated by 0.25g FeCl36H2O and 1L distilled water;

(7) above-mentioned mixed solution is added culture flask and stir, keep 20 ℃ of constant temperature;

(8) the alkali absorption cell of packing into of the top in culture flask, the cultivation bottle cap sealing of screwing;

(9) will reset with reference to the air pressure end;

(10) if continue to be provided with other pipe passages, repeating step (1)-(9) then;

(11) keep 20 ℃, timing was cultivated 120 hours, before timing, the little differential pressure sensor on the said passage was put 0;

Little differential pressure sensor when (12) detecting the timing end point carries out data processing and obtains experimental result;

(13) experimental result data that obtains is sent to computer, preserves and select and whether print;

(13) open the bleeder valve waste liquid of releasing, and with distilled water flushing culture flask three times.

7. method according to claim 6 is characterized in that, the accuracy of detecting instrument before measuring actual water sample.

8. method according to claim 7 is characterized in that, judges according to the value of the BOD5 of the mark liquid of measuring whether detecting instrument is accurate, and the determination step and the determination step of actual water sample of mark liquid are got rid of step (6), and other execution in step are with in proper order identical.

9. method according to claim 6 is characterized in that, inoculation water is the supernatant of the sanitary sewage under 20 ℃.

10. method according to claim 9 is characterized in that, mark liquid fresh before experiment obtains; Compound method is: get A; B, C, each 2ml of D solution; Distilled water 1992ml is mixed into dilution water 2L, and this dilution water and glucose, each 300mg of glutamic acid are mixed and made into nonvaccinated Portugal-paddy mark liquid; Get supernatant 200ml under 20 ℃ of the 1000ml sanitary sewage constant temperature as inoculation water, inoculate said 1800ml Portugal-paddy mark liquid, promptly get and mark liquid.