GB/T 42992.1-2023Chemicals—Simulation tests to assess the biodegradability of chemicals discharged in wastewater—General considerations (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document is Part 1 of GB/T 42992 "Chemical Simulation Test for Evaluating the Biodegradability of Chemical Substances Emitted in Wastewater".

GB/T 42992 has released the following parts.

---Part 1: General principles.

Introduction

A simulated test series method for evaluating the biodegradability of chemicals discharged from wastewater describes the organicization that enters the environment with wastewater discharges Determination of primary and final biodegradability of chemicals and their degradation kinetics. Personal care, household cleaning and laundry chemicals are normally used After use, it is discharged into the drainage system and becomes a common component in domestic sewage. Similarly, medicines can also be discharged into the drainage system with excrement or in a certain In some cases, it enters the drainage system after treatment. Other chemicals may enter the drainage system due to intermittent or continuous discharges from the production process.

GB/T 42992 "Chemical Simulation Test for Evaluating the Biodegradability of Chemical Substances Emitted in Wastewater" aims to establish the applicable The guidelines for independent but related simulation test methods are planned to consist of six parts.

---Part 1: General principles. The purpose is to establish the general principles that need to be followed in common for this series of simulation test methods.

---Part 2: Biodegradation in sewer systems. The purpose is to accurately evaluate the presence of chemicals in raw sewage in sewage pipe systems. biodegradability in biodegradable materials and establish the principles and procedures that need to be followed.

---Part 3: Biodegradation in activated sludge. The purpose is to provide accurate evaluation of chemicals widely used in biochemical wastewater treatment.

Biodegradability in the system, establishing the principles and procedures that need to be followed.

---Part 4: Mineralization and transformation in anaerobic digestion sludge. The purpose is to accurately evaluate the use of chemicals in the sludge anaerobic digestion process. biodegradability in biodegradable materials and establish the principles and procedures that need to be followed.

---Part 5: Biodegradation in the secondary effluent-surface water mixing zone. The purpose is to provide an accurate assessment of the Biodegradability of chemicals discharged from effluent into surface waters and establish principles and procedures to be followed.

---Part 6: Biodegradation in the direct discharge sewage-surface water mixing zone. The purpose is to provide an accurate assessment of chemicals accompanying untreated wastewater. to manage the biodegradability of discharges directly into surface waters and establish the principles and procedures to be followed.

This part is used in combination with the other five parts and is suitable for evaluating the biodegradation of chemicals in sewage pipe systems, in activated sludge Biodegradation, mineralization and transformation in anaerobic digestion sludge, biodegradation in the secondary effluent-surface water mixing zone and in direct discharge sewage- Primary and final biodegradability in surface water mixing zones. The biodegradability of chemicals in each of the above sections is important for determining their correlation with each other.

The exposure levels of aquatic and terrestrial habitats play an important role.

Figure 1 represents the most common migration pathways of chemicals during wastewater discharge. When sewage enters sewage treatment plants or environmental discharge points,

During the process, sewage first enters the drainage system and may stay there for hours or days. In most cases, sewage is treated before discharge, but Sometimes sewage is discharged directly into surface water without treatment or only undergoes very simple primary treatment. In a typical sewage treatment plant, about 40%~ 60% of the solid fraction is removed in the primary treatment; the primary effluent is subsequently biologically treated, and all solids are removed in the final sedimentation tank (such as secondary sedimentation tank). pool); then the final effluent (such as secondary effluent) is discharged into surface water. If the sludge disposal method is farmland application, then the primary sedimentation tank and Solid sludge in secondary sedimentation tanks usually requires anaerobic digestion.

Note: ** is the object simulated by 5 methods.

The amount of chemicals discharged into the environment with the final effluent (secondary effluent) or combined with sludge solids is a function of chemical distribution behavior, biodegradation rate and The result of the combined action of other processes (e.g., volatilization, hydrolysis, photolysis, adsorption). Chemical residence time, bioactivity levels and biodegradation The key links for solution removal include. in sewage pipes, during aerobic secondary treatment of sewage and anaerobic digestion of sludge. Therefore, these three systems It is most important for simulating the determination of biodegradation removal of chemicals during wastewater migration and treatment processes. In addition, chemical releases into the environment Afterwards, further biodegradation can occur in environmental water bodies. Therefore, as chemicals are discharged from wastewater discharge points into water bodies, during mixing Biodegradability in strips, water, and biomass solids is key to predicting concentrations and exposure levels of chemicals in downstream water bodies.

These five simulation test methods include a batch of open intermittent test systems or closed gas through-flow test systems, which include

GB/T 21801, GB/T 21802, GB/T 21803, GB/T 21829, GB/T 21831, GB/T 21856, GB/T 21857, Basic elements of GB/T 27850, GB/T 27857, GB/T 35523 and other methods. The main purpose of these five methods is to determine the initial properties of chemicals. grade biodegradation rate, mineralization rate, and further determination of main transformation products and their removal if necessary. In addition, if appropriate analytical methods are available, it can Qualitative and quantitative analysis of the main transformation products.

These test methods are designed to accurately evaluate new or existing chemicals entering the environment with continuous or intermittent discharges of sewage of biodegradability. In some cases, the obtained kinetic constants can be used as input constants in exposure models for risk assessment. These tests are intended to As a higher level test used to evaluate the biodegradability of non-biodegradable chemicals in Organization for Economic Co-operation and Development (OECD) screening tests biodegradability, or for use in determining biodegradation rates in exposure assessments.

Chemical evaluation of chemicals released into wastewater General rules for simulation tests of biodegradability Warning---Personnel using this document should have practical experience in regular laboratory work. This document does not address all possible security issues question. Users are responsible for taking appropriate safety and health measures and ensuring compliance with the conditions stipulated in relevant national regulations.

1 Scope

This document describes the general test principles and five test methods for chemical simulation tests to evaluate the biodegradability of chemicals discharged into wastewater.

Applicability and limitations of test methods, test substance information, reference substances, quality assurance and quality control, data and reporting.

This document is applicable to water-soluble or weakly water-soluble and non-volatile test substances, and can also be used for the determination of volatile test substances.

This series of documents is not applicable to the determination of nitrogen and phosphorus removal from wastewater.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 21796 Chemical activated sludge respiratory inhibition test

GB/T 21801 Respirometry test for rapid biodegradability of chemicals

GB/T 21802 MITI test for improvement of rapid biodegradability of chemicals (I)

GB/T 21803 DOC reduction test for rapid biodegradability of chemicals

GB/T 21816 Zane-Whalens test for inherent biodegradability of chemicals

GB/T 21817 Semi-continuous activated sludge test for improved inherent biodegradability of chemicals

GB/T 21831 Rapid biodegradability of chemicals closed bottle test

GB/T 21845 Chemical water solubility test

GB/T 21852 Chemical Partition Coefficient (n-octanol-water) High Performance Liquid Chromatography Test

GB/T 21853 Chemical partition coefficient (n-octanol-water) shake flask method test

GB/T 21855 pH-related hydrolysis test of chemicals

GB/T 21856 Carbon dioxide production test for rapid biodegradability of chemicals

GB/T 21857 OECD screening test for improved rapid biodegradability of chemicals

GB/T 22052 Method for determining the vapor pressure-temperature relationship and initial decomposition temperature of liquids using a liquid vapor pressure meter

GB/T 22228 Static method for determination of vapor pressure of industrial chemical solids and liquids in the range of 10-1Pa to 105Pa

GB/T 22229 Determination of vapor pressure of industrial chemical solids and liquids in the range of 10-3Pa to 1Pa equity

GB/T 27850 General principles for rapid biodegradability of chemicals

GB/T 27853 Test for aerobic and anaerobic conversion of chemicals in water-sediment systems

GB/T 27856 Test for aerobic and anaerobic conversion of chemicals in soil

GB/T 29882 Test methods for classification of miscellaneous hazardous substances and articles n-octanol/water partition coefficient OECD Chemical Testing Guideline No.104 Vapor Pressure (VapourPressure)