US4350763A
Expired / Lapsed
US
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Method for determining biochemical oxygen demand
Assignee: Ajinomoto Co Inc
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Filing: 1980-04-07
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Granted: 1982-09-21
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Expires: 2000-04-07
Abstract
Abstract The biochemical oxygen demand (BOD) of an aqueous liquid contaminated with organic matter is determined by contacting a sample solution with elementary oxygen and with immobilized microorganisms capable of aerobically metabolizing the organic matter and of thereby consuming the oxygen. The rate of oxygen consumption under otherwise uniform conditions is as precise a measure of BOD as the conventional five-day test, but is determined within less than two hours, usually less than 30 minutes. A membrane-type oxygen-sensitive electrode is employed for sensing the rate of oxygen consumption and generates an output signal which is readily correlated with the BOD of the tested liquid.
Inventors
- 👤 Shuichi Suzuki
- 👤 Isao Karube
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:12
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/1806; Y; Y10; Y10S; Y10S435/00; Y10S435/817
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
150 words
A method of determining the biochemical oxygen demand of an aqueous liquid containing organic matter which comprises (a) contacting a sample of said liquid with molecular oxygen and with a microbial electrode comprising an oxygen-sensitive electrode covered by first and second membranes which are permeable to said liquid and oxygen and impermeable to microbial cells and microorganisms immobilized or confined between the membranes, said microorganisms being capable of aerobically metabolizing said organic matter and thereby consuming said oxygen, (b) electrochemically sensing the rate of consumption or the decrease in steady state concentration of said oxygen caused by said microorganisms during a period not exceeding two hours; and (8c) calculating the biochemical oxygen demand from said rate of consumption or said decrease of the oxygen by making use of the direct linear relationship between the biochemical oxygen demand and the rate of consumption or the decrease of the amount of oxygen.
Claim 2
Independent Claim
150 words
A method of determining the biochemical oxygen demand of an aqueous liquid containing organic matter which comprises (a) contacting a sample of said liquid with molecular oxygen and with a microbial electrode comprising an oxygen-sensitive electrode covered by first and second membranes which are permeable to said liquid and oxygen and impermeable to microbial cells and microorganisms immobilized or confined between the membranes, said microorganisms being capable of aerobically metabolizing said organic matter and thereby consuming said oxygen, (b) electrochemically sensing the rate of consumption or the decrease in steady state concentration of said oxygen caused by said microorganisms during a period not exceeding two hours; and (8c) calculating the biochemical oxygen demand from said rate of consumption or said decrease of the oxygen by making use of the direct linear relationship between the biochemical oxygen demand and the rate of consumption or the decrease of the amount of oxygen.
Claim 3
Dependent Claim
16 words
A method as set forth in claim 1 wherein said second membrane is a dialysis membrane.
Claim 4
Independent Claim
159 words
A method of determining the biochemical oxygen demand of an aqueous liquid containing organic matter which comprises (a) contacting a sample of said liquid with molecular oxygen and with a microbial electrode comprising an oxygen sensitive electrode covered by a first directly adjacent membrane and a second adjacent membrane, said membranes being permeable to said liquid and oxygen and impermeable to microbial cells and microorganisms immobilized or confined within said second membrane, said microorganisms being capable of aerobically metabolizing said organic matter and thereby consuming said oxygen, (b) electrochemically sensing the rate of consumption or the decrease in steady state concentration of said oxygen caused by said microorganisms during a period not exceeding two hours; and (c) calculating the biochemical oxygen demand from said rate of consumption or said decrease of the oxygen by making use of the direct linear relationship between the biochemical oxygen demand and the rate of consumption or the decrease of the amount of oxygen.
Claim 5
Independent Claim
159 words
A method of determining the biochemical oxygen demand of an aqueous liquid containing organic matter which comprises (a) contacting a sample of said liquid with molecular oxygen and with a microbial electrode comprising an oxygen sensitive electrode covered by a first directly adjacent membrane and a second adjacent membrane, said membranes being permeable to said liquid and oxygen and impermeable to microbial cells and microorganisms immobilized or confined within said second membrane, said microorganisms being capable of aerobically metabolizing said organic matter and thereby consuming said oxygen, (b) electrochemically sensing the rate of consumption or the decrease in steady state concentration of said oxygen caused by said microorganisms during a period not exceeding two hours; and (c) calculating the biochemical oxygen demand from said rate of consumption or said decrease of the oxygen by making use of the direct linear relationship between the biochemical oxygen demand and the rate of consumption or the decrease of the amount of oxygen.
Claim 6
Dependent Claim
18 words
A method as set forth in claim 1 or 3 wherein said second membrane is a microbial-collagen membrane.
Claim 7
Dependent Claim
20 words
A method as set forth in claim 4 wherein said microorganisms are those which have been washed with a phosphate.
Claim 8
Dependent Claim
22 words
A method as set forth in claim 1 or 2 wherein said sample solution is saturated with said oxygen during said period.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |