Comprehensive Protocol for Solid Waste Toxicity Leaching Tests Using JRY Instruments

I. Selection of Leaching Methods

The leaching toxicity testing methods for solid waste specified by environmental standards primarily encompass three approaches: the Acetic Acid Buffer Solution Method (HJ/T 300-2007), the Sulfuric Acid-Nitric Acid Method (HJ/T 299-2007), and the Horizontal Oscillation Method (HJ 557-2010). Each method possesses distinct characteristics and is suited for different applications. The Acetic Acid Buffer Solution Method is renowned for its applicability to industrial waste in landfills, while the Sulfuric Acid-Nitric Acid Method excels in the treatment of general waste in open-air settings. The horizontal oscillation method is suitable for assessing the leaching risk of inorganic pollutants (excluding unstable pollutants such as cyanides and sulfides) in solid wastes and other solid materials when subjected to leaching by surface water or groundwater. Therefore, when selecting a leaching method, factors such as waste source, properties, and disposal methods must be comprehensively considered. Following standard guidelines, the most appropriate leaching method should be chosen. This article focuses on explaining the first two methods.

II. Preparation of Testing Equipment

To ensure the accuracy and reliability of leaching tests, the preparation of experimental equipment is critical. Required equipment includes: a 30±2 r/min rotary shaker, a Zero Headspace Extractor (ZHE), 2L wide-mouth bottles, a high-pressure or vacuum filter, filter membranes (0.6-0.8 μm), a pH meter, 500ml stainless steel or glass pipettes, and a balance (accuracy ±0.01g). Notably, Hunan Jinrongyuan Instrument Equipment Co., Ltd. successfully developed and marketed China's first domestically-patented rotary shaker as early as 2007, providing robust assurance for precise leaching test execution.

III. Sample Processing and Storage

For granular samples with larger particle sizes, reduce particle size to below 9.5 mm through crushing, cutting, or grinding. Samples must be stored at 4°C refrigeration to prevent loss of volatile substances. Leaching procedures for volatile and non-volatile organic compounds must strictly adhere to relevant standards. Prior to leaching, moisture content determination is essential, as results serve as a basis for formulating subsequent extraction agents. Note: Samples tested for moisture content should not be reused for subsequent toxicity leaching tests.

IV. Implementation of the Leaching Process

The leaching procedure for volatile organic compounds is as follows: Accurately weigh 20–25g of sample, promptly transfer it into the ZHE zero-headspace extractor, pressurize to expel headspace air, and collect the initial liquid phase for refrigerated storage. If the solid percentage is less than 5%, analyze the initial liquid directly. Otherwise, proceed with subsequent leaching steps, then mix the leachate with the initial liquid for analysis.

For other leaching scenarios, first filter the sample through a filter. If the solid percentage is less than 5%, analyze the initial liquid directly. Otherwise, similarly proceed with subsequent leaching steps, then mix the leachate with the initial liquid for analysis. The formulation of the extraction agent must be adjusted according to the sample's moisture content. During extraction, maintain a rotation speed of 30±2 r/min and agitate at 23±2°C for 18±2 hours. After extraction, filter the extract and store it properly.

V. Analysis and Processing of Leachate

If the leachate is to be used for metal analysis, it must undergo digestion treatment according to the corresponding analytical method. Specific analysis steps for the leachate should refer to other environmental protection standards. Through scientific analysis and processing, the leaching toxicity of solid waste can be accurately assessed, providing strong support for environmental protection and waste treatment. For any inquiries, please consult the engineers at Hunan Jinrongyuan Instrument Equipment Co., Ltd.