Standard No.:	GB/T 5750.7-2023
English Name:	Standard examination methods for drinking water—Part 7: Aggregate organic indices
Chinese Name:	生活饮用水标准检验方法 第7部分：有机物综合指标
Chinese Classification:	C51    Environmental sanitation
Professional Classification:	GB    National Standard
Issued by:	SAMR; SAC
Issued on:	2023-03-17
Implemented on:	2023-10-1
Status:	valid
Superseding:	GB/T 5750.7-2006 Standard examination methods for drinking water - Aggregate organic parameters
Language:	English
File Format:	PDF
Word Count:	13500 words
Price(USD):	405.0
Delivery:	via email in 1~5 business day

Foreword This document is drafted in accordance with the provisions of GB/T 1.12020 "Standardization Work Guidelines Part 1 Structure and Drafting Rules for Standardization Documents This document is part 7 of GB/T 5750 "Standard Test Methods for Drinking Water". GB/T 5750 has published the following parts. Part 1: General Provisions. Part 2: The collection and preservation of water samples. Part 3: Quality control of water quality analysis. Part 4: Sensory properties and physical indicators Part 5: Inorganic non-metallic indicators. Part 6: Metal and metal-like indicators. Part 7: Organic composite indicators. Part 8: Organic indicators Part 9: Pesticide indicators. Part 10: Disinfection by-product indicators Part 11: Disinfectant indicators. Part 12: Microbial indicators. Part 13:Radioactive indicators. This document replaces GB/T 5750.7-2006 "Standard Test Methods for Drinking Water Organic Matter Comprehensive Index" compared with GB/T 5750.7-2006, in addition to structural adjustments and editorial changes, the main technical changes are as follows. a) increased the "terms and definitions" (see Chapter 3) b) The addition of three test methods (see 4.3, 4.7.2). c) Changed the indicator "oxygen consumption" to "permanganate index (in O)" (see chapter 4, chapter 1 of the 2006 edition) Please note that some of the contents of this document may be patent related. The publisher of this document does not assume responsibility for identifying patents. This document is proposed by and attributed to the National Health Care Commission of the People's Republic of China. Introduction GB/T 5750 "Standard Test Methods for Drinking Water" as the recommended national standard for drinking water testing technology and GB 5749 "Drinking Water Sanitation Standards" supporting the important technical support of GB 5749, for the implementation of GB 5749, to carry out health and safety assessment of drinking water to provide test methods. GB/T 5750 consists of 13 parts. Part 1: General Provisions. The purpose is to provide the basic principles and requirements of water quality testing. Part 2: the collection and preservation of water samples. The purpose is to provide water samples collected, preservation, management, transport and sampling quality control of the basic principles, measures and requirements. Part 3: quality control of water quality analysis. The purpose is to provide water quality inspection and testing laboratory quality control requirements and methods Part 4: Sensory traits and physical indicators. The purpose is to provide sensory traits and physical indicators of the corresponding test methods Part 5: inorganic non-metallic indicators. The purpose is to provide inorganic non-metallic indicators of the corresponding test methods Part 6: Metals and metal-like indicators. The purpose is to provide metal and metal-like indicators of the corresponding test methods Part 7: Organic composite indicators. The purpose is to provide a comprehensive index of organic substances corresponding test methods Part 8: organic indicators. The purpose is to provide the corresponding test methods for organic indicators. Part 9: Pesticide indicators. The purpose is to provide the corresponding test methods for pesticide indicators. Part 10: Disinfection by-products indicators. The purpose is to provide the corresponding test methods for disinfection by-product indicators Part 11: Disinfectant indicators. The purpose is to provide the corresponding test methods for disinfectant indicators Part 12: Microbiological indicators. The purpose is to provide the corresponding test methods for microbial indicators Part 13: radioactive indicators. The purpose is to provide the corresponding test methods for radioactive indicators 1 Scope This document describes the determination of permanganate index (in 0) oil, total organic carbon in drinking water and water source water permanganate index (in O) biochemical oxygen demand (BOD) oil, total organic carbon determination method. This document applies to the determination of the comprehensive index of organic matter in drinking water and (or) water source water 2 Normative reference documents The following documents constitute the essential provisions of this document through the normative references in the text. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; do not note the date of the reference document, its latest version (including all the revision of the list) applies to this document. GB/T 5750.1 Standard test methods for drinking water Part 1: General Provisions GB/T 5750.3 Standard test methods for drinking water Part 3: Quality control of water quality analysis GB/T 5750.4-2023 Standard test methods for drinking water Part 4: sensory properties and physical indicators GB/T 6682 Analytical laboratory water specifications and test methods 3 Terms and definitions GB/T 5750.1, GB/T 5750.3 defined terms and definitions apply to this document 4 Permanganate index (in 0,count) 4.1 Acidic potassium permanganate titration method 4.1.1 Minimum detection mass concentration 4.2 Alkaline potassium permanganate titration method 4.2.1 Minimum detectable mass concentration This method applies to the determination of chloride mass concentration higher than 300mg/L (in CI) of drinking water and its source water permanganate index (in 0). The minimum detection quality concentration of this method (when taking 100ml of water samples) is 0.05mg/L (in terms of 0), the maximum determination of permanganate index (in terms of O) quality concentration of 50mg/L. 4.2.2 Principle Potassium permanganate oxidizes reducing substances in alkaline solution, and after acidification, excess potassium permanganate is titrated with sodium oxalate solution 4.2.3 Reagents 4.2.3.1 Sodium hydroxide solution (500g/L): weigh 50g of oxidation (NaH), dissolve in pure water and dilute to 100mL. 5 Biochemical oxygen demand (BOD) 5.1 Volumetric method 5.1.1 Principle Biochemical oxygen demand is the amount of dissolved oxygen required for the biochemical process of microbial decomposition of organic matter in water under aerobic conditions, take the raw water or diluted water samples, so that it contains sufficient dissolved oxygen, the sample will be divided into two parts at the same time, one to determine the mass concentration of dissolved oxygen on the day, and the other into the 20C incubator for 5d and then measured the mass concentration of dissolved oxygen, the difference between the two is the five-day biochemical oxygen demand ( BOD,). 5.1.2 Reagents 5.1.2.1 Calcium chloride solution (27.5g/L) Weigh 27.5g of anhydrous chloride (CaCl) dissolved in pure water and dilute to 1000mL. 5.1.2.2 Ferric chloride solution (0.25g/L): weigh 0.25g of ferric chloride hexahydrate (FeCl-6HO) dissolved in pure water, dilute to 1000mI 6 Petroleum 6.1 Weighing method 6.1.1 Principle After extraction of water samples by petroleum ether, evaporation to remove petroleum ether, weighing, and calculate the content of petroleum in water. The results measured by this method is the total amount of substances extractable by petroleum ether in water. 6.1.2 Reagents 6.1.2.1 sulfuric acid (p2 = 1.84g/mL). 6.1.2.2 Petroleum ether (boiling range 30 "C ~ 60C): by 70C water bath re-evaporation to stay 6.2 UV spectrophotometric method 6.2.1 Minimum detectable mass concentration The minimum detection mass of this method is 5g, if 1000mL of water samples are taken for determination, the minimum detection mass concentration is 0.005g/L. 6.2.2 Principle The substances contained in the petroleum composition with co-driven system have characteristic absorption in the UV region. Aromatic compounds with benzene rings mainly absorb at 250nm~260nm; compounds with co-double bonds mainly absorb at 215nm~230nm; crude oil in general has two absorption peaks at 225nm and 256nm; other oils such as fuel oil lubricants have absorption peaks similar to crude oil, and some oils have only one absorption peak. Some oils such as gasoline are not absorbed after refining. Therefore, in the measurement should pay attention to the selection of suitable standards, crude oil and heavy oil optional 256nm; light oil optional 225nm, when available, can be taken from the polluted water or from the source of pollution to obtain the determination of the standard. 6.2.3 Reagents 6.2.3.1 anhydrous sodium sulfate: dry at 400C for 1h, cool and store in a tightly closed reagent bottle 7 Total organic carbon 7.1 Direct determination method 7.1.1 Minimum detection mass concentration The minimum detectable mass concentration of this method is 0.5mg/L. 7.1.2 Principle To the water sample with the appropriate oxidant, or ultraviolet catalysis (TiO) and other methods, so that the water organic carbon to carbon dioxide (CO). Inorganic carbon is removed by acidification and purging, or measured separately. The generated CO can be directly measured, or reduced to CH, and then measured.CO determination methods include: non-dispersive infrared spectroscopy, titration (preferably in non-aqueous solutions) thermal conductivity cell detector (TCD) conductivity titration, power titration, CO-sensitive electrode method and the reduction of CO to CH after the flame ionization detector (FID). 7.2 Membrane conductivity determination method 7.2.1 Minimum detection mass concentration The minimum detection mass concentration of this method is 0.20mg/L. 7.2.2 Principle The organic carbon in water is converted to CO2 by adding appropriate oxidant to the water sample or using UV catalysis, etc. The inorganic carbon is removed by acidification and degassing, or measured separately. The generated CO is measured using a selective thin film conductivity detection technique.

Foreword Introduction 1 Scope 2 Normative reference documents 3 Terms and definitions 4 Permanganate index (in 0,count) 5 Biochemical oxygen demand (BOD) 6 Petroleum 7 Total organic carbon