GB/T 14643.1-2009 English PDF (GBT14643.1-2009)

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GB/T 14643.1-2009: Examination of bacteria and algae in industrial circulating cooling water -- Part 1: Examination of bacteria formed deposits -- Standard of plate count
GB/T 14643.1-2009
GB
ICS 71.040.40
G 76
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing GB/T 14643.1-1993
Examination of bacteria and algae in industrial
circulating cooling water - Part 1. Examination of
bacteria formed deposits - Standard of plate count
ISSUED ON. MAY 18, 2009
IMPLEMENTED ON. FEBRUARY 1, 2010
Issued by.
General Administration of Quality Supervision, Inspection
and Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of
China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Method summary ... 4
4 Reagents and materials ... 4
5 Instruments and equipment ... 5
6 Preparation before the trial ... 5
7 Examination procedure ... 7
8 Counting and report ... 9
9 Precision ... 10
Foreword
GB/T 14643 Examination of Bacteria and Algae in Industrial Circulating Cooling Water is
divided into the following parts.
— Part 1. Examination of bacteria formed deposits Standard of plate count
— Part 2. Examination of soil bacteria Standard of plate count
— Part 3. Examination of slime fungus Standard of plate count
— Part 4. Examination of soil fungus Standard of plate count
— Part 5. Examination of sulfate reducing bacteria MPN method
— Part 6. Examination of iron bacteria MPN method
This Part is part 1 of GB/T 14643.
This Part replaces GB/T 14643.1-1993 Industrial circulating cooling water--Examination of
bacteria formed deposits - Standard of plate count
Compared with GB/T 14643.1-1993, there is no difference in technical content, except that
the text structure and wordings are modified.
This Part was proposed by China Petroleum and Chemical Industry Association.
This Part shall be administered by Water Treatment Agent Subcommittee of National
Standardization Technical Committee in Chemistry (SAC/TC 63/SC 5).
Responsible drafting organizations of this Part. CNOOC Tianjin Chemical Research and Design
Institute, and Shanghai Weilai Enterprise Co., Ltd.
Main drafters of this Part. Zhu Chuanjun, Liu Xin, Zhang Quan, Bai Ying, and Li Lin.
This part was first issued in 1993.
Examination of bacteria and algae in industrial circulating
cooling water - Part 1. Examination of bacteria formed deposits -
Standard of plate count
1 Scope
This Part of GB/T 14643 specifies examination of bacteria formed deposits in industrial
circulating cooling water.
This part applies to the examination of heterotrophic bacteria in suspended slime in industrial
circulating cooling water, and the examination of heterotrophic bacteria in deposited slime in
industrial circulating cooling water. It also applies to the examination of slime heterotrophic
bacteria in raw water, domestic water and other water.
2 Normative references
The articles contained in the following documents have become part of this Part when they
are quoted herein. For the dated documents so quoted, all the modifications (excluding
corrections) or revisions made thereafter shall not be applicable to this Standard. For the
undated documents so quoted, the latest editions shall be applicable to this Standard.
GB/T 603 Chemical reagent--Preparations of reagent solutions for use in test methods
(GB/T 603-2002, ISO 6353-1.1982, NEQ)
GB/T 6682 Water for analytical laboratory use - Specification and test methods (GB/T
6682-2008, ISO 3696. 1987, MOD)
3 Method summary
In this method, No. 25 plankton net is used to collect the slime in circulating cooling water, the
collected slime is fully grinded with quartz sand to make the cell scattered, and then plate
counting technique is used to cultivate them under (29±1)ºC for 72h to measure the total
number of heterotrophic bacteria in the slime.
4 Reagents and materials
Unless otherwise specified, the reagents in this part shall be analytical reagent and shall be
compliance with the provisions of Grade-3 water in GB/T 6682.
Preparations and products needed in the trial shall be prepared and based on the provisions
of GB/T 603 if there is no other requirement.
7.4 Cultivation
When the culture medium (7.3.7) is solidified in the petri dish, INVERT the plate. CULTIVATE
it for 72 h in the biochemistry incubator at (29 ± 1) ºC.
8 Counting and report
8.1 After cultivation, TAKE out the petri dish. If colonies occur on the blank petri dish, it
indicates that pollution exists during the examination and this examination is invalid.
8.2 SELECT the degree of dilution with average colony count in the range of 30-300. COUNT
immediately. GET the average colony count. And ROUND off the results into two significant
figures (see example 1 in Table 1).
8.3 If there are two degrees of dilution, and their growing colony counts are in the range of
30-300, then it shall be decided by the ratio between them. If the ratio is smaller than 2, the
average shall be reported; if the ratio is greater than 2, the smaller one shall be reported (see
sample 2 and sample 3 in Table 1).
8.4 If the average number of colonies of all dilutions exceeds 300, it shall select the petri dish
with the highest dilution to count (see Example 4 of Table 1).
8.5 If the average number of colonies of all dilutions is less than 30, it shall select the petri
dish with the lowest dilution to count (see Example 5 of Table 1).
8.6 If all dilution degrees have no colony growth, it shall report in accordance with “< 1 × (the
minimum dilution ratio)" (see Example 6 of Table 1).
8.7 If average colony count for all the degrees of dilution does not fall in the range of 30-300,
which means part of them is greater than 300 and part of others is less than 30, then it selects
the petri dish, of which the average colony count is the most close to 30 or 300, for count (see
example 7 in Table 1).
8.8 The number of mucus-forming bacteria is expressed by p, in unit of pieces per milliliter
(pcs/mL), and CALCULATE in accordance with Formula (2).
Where.
X1 — The average number of colonies calculated in accordance with (8.2) on the petri dish, in
the unit of pcs;
V — The amount of slime calculated in accordance with (7.1.3), in the unit of ml/m3;
V3 — Numerical value of volume of the slime used for examination, in the unit of mL;
K — For examination in accordance with (7.1.4), the ratio of volume (V3) of the slime taken
and the total volume (V2) of the slime;
F — Dilution degree of samples of count group.
Table 1
Examples
Dilution and colony
count
The ratio of the number
of colonies for two
kinds of dilution degree
The total number of
slime-forming bacteria /
(pcs/mL)
Report
Pattern
(pcs/mL) 10-1 10-2 10-3
1 - 164 20 - 16400 1.6×104
2 - 295 46 1.6 37750 3.8×104
3 - 271 60 2.2 27100 2.7×104
4 >6500
Estimation
313 - 313000 3.1×105
5 27 11 5 - 270 2.7×102
6 0 0 0 - < 1×10 < 10
7 - 306 12 - 30600 3.1×104
9 Precision
9.1 Because the microbes can exist in the form of individuals, pairs, chains, clusters or
groups, etc., and there is no single culture medium that can meet physiological requirements
of all bacteria in a water sample. Therefore, the number of colonies obtained from the method
may be less than the number of normal living cells.
9.2 Standard plate counting accuracy increases along with the increase of parallel sample
dish. when 5 parallel dishes are used, degree of confidence for the examination results
obtained by adding 1mL of sample to each dish is 95%.