ISO/TC 281 - Fine bubble technology

This document specifies evaluation methods for determining the content of reactive oxygen species (ROS) used in the FB-facilitated advanced oxidation for pollution abatement in the wastewater treatment process. The probe based kinetic model is applicable to systems that generate ROS in substantial quantities, rather than at physiological concentrations, and is applicable to short-lived ROS. However, it is not applicable to long-lived ROS, such as ozone (O3) and hydrogen peroxide (H2O2). The probe based kinetic model method specifies: — cumulative concentration of different types of ROS during the reaction process; — concentration of different types of ROS at each time point during the reaction process. This method does not define the mechanisms of ROS generation, nor the correlation between bubble size and ROS production.

This International Standard specifies the evaluation methods for ROS in pollutant abatement through FB-facilitated advanced oxidation treatment.

This document specifies a test method for evaluating the effect of fine bubble water on the growth promotion of hydroponically grown lettuce by estimating the incremental gain in mass of the stems and leaves over a specified growth period.

This document specifies the principle, devices and operations for measuring bubble size distribution of microbubbles in liquid media using the in-situ dynamic image method. This document is applicable to microbubbles, as well as to bubbles in the size range of 100 μm to 500 μm, dispersed in transparent liquid media, mostly in water.

This document describes the test methodology to evaluate the aeration performance of fine bubble jet devices based on an evaluation of the mass transfer coefficient of oxygen from gas to water. It is applicable to evaluate the performance of fine bubble jet devices for aeration purpose.

This document provides practical data collection of promoting the germination of typical vegetable seeds by applying ultrafine bubbles (UFBs) within the effective number concentrations for barley seeds specified in ISO 23016-2, ISO/TR 23016-3 and ISO 23016-4. While the application of UFB to barley seeds is systematically standardized, reports on UFB application to vegetable seeds germination are scattered worldwide. Therefore, this document intends to illustrate the effectiveness of UFBs to promote the germination of vegetable seeds depending on their response to light, i.e.: a) require light to germinate (positive photoblastic), b) require darkness to germinate (negative photoblastic), and c) neutral to light.

This document specifies the evaluation methods for hydrogen content in ultrafine bubble (UFB) dispersions. The titration (oxidimetry) method can be used as a quick method to estimate the hydrogen content in hydrogen UFB dispersions. The lower limit of detection is 0,1 mg/l, and the range with acceptable accuracy is between 0,2 mg/l and 1,6 mg/l. The existence of oxidizing or reducing substances in dispersions influences measurement accuracy. The gas chromatographic method features a considerably high accuracy range and lower limit of detection. The existence of UFBs in water does not influence the measurement results. The existence of oxidizing or reducing substances in water does not affect the measurement accuracy either. However, the measurement procedure is time consuming. NOTE This document only provides a method for determining hydrogen contents in UFB dispersions and does not involve the specific effects of hydrogen UFB dispersion application.

This document specifies the evaluation method for size and concentration indices of fine bubbles generated from the fine bubble showerhead device. It is only applicable to fine bubble dispersion in water generated from fine bubble showerhead devices using air. It describes the sampling method for fine bubble dispersion in water from the fine bubble showerhead devices into the retention container and the measurement procedure of size and concentration indices. NOTE The discharging drive force for fine bubble showerhead devices is applied using a pump or water pressure. Therefore, the test of the subject device is performed under environmental conditions including such a practical environment.

This document specifies the evaluation methods for size and concentration indices of fine bubbles (FBs) generated through a nozzle. It only applies to FB dispersions (FBDs) in water generated through the nozzle. It describes the sampling method for a FBD from the nozzle into the retention container and the measurements of size and concentration indices. Major applications of the equipment include components of various industrial water systems and consumer baths and kitchens.

This document specifies evaluation methods for surface tension of ultrafine bubble (UFB) dispersion in water. Three test methods, Wilhelmy, du Noüy and the pendant drop method, are adopted because of their advantages to detect small change in surface tension by UFB dispersion in water and the high accessibility to commercially available instruments. This document can be used to measure the surface tension of liquid containing UFB dispersion in dilute surfactant water solution such as detergent or machining coolant as well as UFB dispersion in water. NOTE Measurement data of liquid containing UFB dispersion in dilute surfactant water solution are summarized in Annex D.

This document specifies evaluation methods for the oxygen content in fine bubble dispersion in water. Three test methods which are adopted include the optical sensor, the electrochemical probe and the iodometric method. The first two methods have an advantage in availability of in situ and real-time measurement, and high accessibility to commercially available instruments. The last one, composed of a well-established chemical analysis procedure, is advantageous in the situation where the instruments to be used in the first two methods are unavailable. The detection limits of the electrochemical and optical sensor methods are stated in the instruction manuals of the instruments, in most cases 0,1 mg/l or 0,2 mg/l. The upper limit depends on the specification of the instrument used. Most instruments allow measurement of a supersaturated sample. Measurement range of the iodometric method is between 0,2 mg/l and 20 mg/l. NOTE Chemical analysis methods other than the iodometric method can be applied[1] as an alternative.

This document specifies a test method for assessing bactericidal viability of Escherichia coli as a test micro-organism, in dispersions of various fine bubbles generated by the hydrodynamic cavitation of water medium.

This document specifies a method to assess the ultrafine bubble (UFB) number concentration in order to find whether the number concentration of UFB generated by users is in the adequate range for promoting the barley seed germination stably irrespective of seed variety conforming to ISO 23016-2 and ISO/TR 23016-3.

This document specifies the general principles of the definition of bubbles with shells, including the gas-filled structures/particles dispersed in liquids. The shell cited in this document is one created deliberately in manufacturing. Shells created by naturally occurring layers created on the surface of bubbles due to adhesion of bubbles are out of the scope of this document.

This document specifies a test procedure, equipment and environment for evaluating the concentration loss of ultrafine bubbles (UFB) due to long-distance transfer of ultrafine bubble water in a plastic pipe. The test results are analysed and expressed in terms of a formula with the flow parameters, pipe length, flow velocity and number of circulations through the pipe. The formula is intended to be used for designing long-distance transport system for industrial applications including agro- and aqua- farming.

This document provides in detail how the standards of fine bubble technologies can contribute to establish the systematic classification of fine bubble technologies including the effective functions and the application fields of fine bubbles, which is useful for the users and the potential customers to optimize the application of fine bubble technologies.. This document also specifies the clauses required for fine bubble standards, including a description relating application fields and effective functions of fine bubble technologies.

This document specifies a test method to evaluate the oil removal performance from polyester-based textile with fine bubbles.

This document specifies the bubble volume concentration and bubble bed depth measurement methods by online particle counter for checking DAF process performance in plant. The test method of bubble volume concentration is made by measuring bubble size distribution in contact zone of DAF tank and calculating using formula. And bubble bed depth is evaluated by measuring the number of bubbles and particles according to the depth at five points in separation zone of DAF tank. This document provides the advantages and limitations of using online particle counter in plant.

This document specifies the evaluation of fine bubbles size and concentration indices applied to the combined use of number-based size analysis and volume-based size analysis by the laser diffraction method. The methodology described is appropriate to both bimodal and multimodal samples over a broad size range (from tens of nanometers to tens of micrometers) and applies to ultrafine bubble and microbubble dispersions (MBD) and mixtures thereof.

This document demonstrates guidelines for promoting the germination of barley seeds with a lower number concentration of ultrafine bubbles (UFB). This is achieved by taking the data concerning the germination ratio of barley seeds conforming to ISO 23016-2 as a starting point and then evaluating the minimum number concentration range of ultrafine bubble water necessary for promoting the effect on germination of barely seeds by changing germination time.

This document describes methods for generating fine bubbles.

This document specifies the elimination techniques for removing fine bubbles from fine bubble dispersion in water and how to optimize the elimination procedures to obtain better efficiency. This document is applicable to fine uncoated bubbles (without shells). It does not apply to fine coated bubbles (with shells). NOTE Fine bubbles dispersed in liquid are classified into “fine bubble with shells” and “fine bubble without shells”. Fine bubble with shells means the fine bubble whose surface/interface is covered almost completely by an object or a collection of objects.

This document specifies a test method for the cleaning of hard flooring surfaces. It can be used to demonstrate the comparative cleaning performance of a fine bubble solution to an alternate cleaning solution to remove contaminant from a soiled surface. This alternate cleaning solution can be another fine bubble solution, municipal tap water or a commercially available cleaning solution blended to the manufacturer’s specifications. This method is not suitable for differentiating between cleaning solutions when the contaminant is excessively applied on the surface as the mechanism of cleaning changes.

This document provides guidelines for suppliers to show in which part of the Sustainable Development Goals fine bubble technologies can contribute to users. This document also provides guidelines for document writers to assess the contribution of their documents related to fine bubble technology to the Sustainable Development Goals. It also enables users to understand the benefits of using fine bubble technologies.

This document specifies the terminology related to dissolved air flotation (DAF) bubble bed and its characteristics in the dissolved air flotation process.

This document specifies a test method to assess the performance of ozone fine bubble water generating systems used for decolorizing water-soluble dye in e.g. wastewater and industrial water. This document does not address the impact of ozone on health and environment.

This document specifies the evaluation procedure of fine bubble elimination for fine bubble dispersion in water. This document is applicable only to fine bubbles without shell.

This document focuses on listing most commonly used preparation and characterization techniques for fine bubbles and their interpretation. The merits and limitations of each of the techniques are outlined.

This document describes the test method to evaluate the cleaning performance of ultrafine bubble water when used in high-pressure water jet to wash out salt-stained steel surfaces. The evaluation is carried out by measuring comparative removal of salt stain from the surface of a test plate with the ultrafine bubble water to that with control water.

This document specifies the evaluation method for the size index of microbubbles in microbubble dispersion. It is only applicable to microbubbles with or without shell in water within the range from 1 μm to 100 μm. It describes the sampling methods from the point generating or dispersing microbubbles in the retention container to the detecting point of the measuring instruments.

This document specifies a test method for removal of machine oil stain from a noncorrosive metal surface using fine bubble water. A test is provided to show the comparative cleaning advantage of adding fine bubbles to the water.

This document specifies a method to test the promotion of the germination of barley seeds, using ultrafine bubble (UFB) water produced from an ultrafine bubble water generating system. The performance of the method is assessed by measuring the ratio of barley seed germination.

This document specifies a test method for evaluating the effect of fine bubble water on the growth promotion of hydroponically grown lettuce by estimating the incremental gain in mass of the stems and leaves over a specified growth period.

This document establishes the general principles and descriptors to allow users to describe the quality of the liquid media and the size and concentration of fine bubbles. It is also intended to allow users to classify fine bubbles by rise velocity.

This document specifies procedures and requirements for sampling and sample preparation of ultrafine bubble dispersions in water. This document is applicable to relatively stable dispersions where the size and number of bubbles are relatively constant for the duration of the sampling, sample preparation and measurement. This document is not applicable to less stable fine bubble dispersions or microbubble dispersions.

This document describes the procedures and equipment for storage and transportation of ultrafine bubble dispersions in water and specifies the related requirements in order to maintain such bubble characteristics as size and number concentration.

ISO 20480-1:2017 specifies terminology and definitions used in the area of fine bubble technology. Terminology in this document covers general principles, measurements, and individual applications of fine bubble technology.