CLASSIFYING RESTRICTED SOLID WASTE USING THE TLCP TEST

The NSW DECC or Department of Environment and Climate Change has provided a system for determining if a particular waste material is Restricted Solid Waste:

1. Determine if the waste contains asbestos (making it a Special Waste, in which case asbestos removal may be necessary).
2. If not a Special Waste, see if it is a Liquid Waste.
3. If not a Special or Liquid Waste, see if it is a Pre-classified Waste.
4. If not Special, Liquid or Pre-Classified, determine if it is Hazardous Waste as per the Transport of Dangerous Goods Code.
5. If the waste does not display properties of Hazardous Waste, a chemical analysis should be conducted to determine the waste’s classification.

The generator of the waste must perform a chemical assessment to determine the waste’s classification.  The chemical assessment process is based around the waste’s potential to release chemical contaminants into the environment through contact with liquids, which leads to the production of leachates.  In order to classify the waste, the generator must be certain that the maximum possible levels of contaminants in the waste do not exceed the specific contaminant concentration (SCC) and/or toxicity characteristics leaching procedure (TCLP) test values for that classification.

The two measurable properties of chemical contaminants used to classify waste are: the SCC of any chemical contaminant in the waste, expressed as milligrams per kilogram (mg/kg) and the leachable concentration of any chemical contaminant using TCLP, expressed as milligrams per litre (mg/L).

The SCC test acts as an initial screening test for the classification of a waste. Based on SCC alone, the test value for each contaminant must be less than or equal to the contaminant threshold (CT) value specified and if so it will fall into one of the following classes: · general solid waste ≤CT1 · restricted solid waste ≤CT2. If a waste’s SCC test value exceeds the contaminant threshold value set for general solid waste (CT1), further assessment using the TCLP test may be used. Where the contaminant threshold value set for restricted solid waste (CT2) is exceeded, a TCLP test must be carried out to determine the leachable concentration of that contaminant and the class of waste.  For waste assessment and classification, it is recommended that the sample mean, the sample standard deviation and the 95% upper confidence limit (UCL) of the mean concentration is calculated for each contaminant to ensure that the 95% UCL for the mean concentration is less than or equal to the CT limit value specified for that contaminant.

To establish the waste’s classification using both SCC and TCLP, the test values for each chemical contaminant must be compared with the threshold values and the classification is then determined as follows:

Classification                                      SCC value                               TCLP value

General solid waste                            ≤SCC1                                      ≤TCLP1

Restricted solid waste                         ≤SCC2                                      ≤TCLP2

Hazardous waste                                 >SCC2                                      >TCLP2

If any of the SCC or TCLP threshold values are exceeded for general solid waste, the waste must be classified as restricted solid waste. If any of the SCC or TCLP threshold values are exceeded for restricted solid waste, the waste must be classified as hazardous waste. For waste assessment and classification, NSW EPA recommend that the sample mean, the sample standard deviation and the 95% UCL of the mean concentration is calculated for each contaminant to ensure that the 95% UCL for the mean concentration is less than or equal to the SCC or TCLP limit value specified for that contaminant.

Australian Enviro Services is a professional Waste Management, Tank Removal and Asbestos Removal firm in Sydney.