Data Quality Requirements

Supporting Data

It is essential that accurate and reliable data be provided to support the verification of the environmental technology performance claim.

The following are the criteria for evaluating data quality:

Appropriate Parameters Properly Measured and Collected

The data must demonstrate that the technology has a measurable effect on the specific parameter(s) identified in the performance claim. For example, a technology claimed to have a specific BOD removal capability should be supported by data which show influent and effluent BOD values, taken from the appropriate locations, at the appropriate times, under appropriate operating conditions.

Samples must be collected after sufficient time has elapsed to allow the process to stabilize, to ensure that the samples are representative of the typical process characteristics at the sampling locations. For example, in a continually stirred reactor system, typically 3 residence times are required for effective stabilization.

The samples collected must be taken under appropriate mixing conditions, and in general, this would be at well mixed locations. For example, areas of stagnation in a reactor or dead end pipes should not be used as sampling locations.

The type of sample collected must be appropriate to generate data that can verify the performance of the technology. Grab samples are appropriate when process characteristics of the stream remain constant and composite samples are appropriate when source stream characteristics fluctuate. Composite samples are a number of aliquots collected over a period of time that are then mixed together to form one sample. Flow proportional composite samples should be collected when the discharge flow varies.

The number of samples must be sufficient such that when the data supporting the claim is statistically analyzed, the claim can be accepted. The number of data required in any data set to be statistically acceptable will depend on the variability in the data and the nature of the technology and its application. It is the responsibility of the applicant to ensure that a sufficiently large number of data points are provided, with a sufficiently small variability, to be statistically acceptable.

Acceptable sampling protocols must be used to collect and preserve samples including field and reagent blanks and the use of standard reference materials (SRMs). These protocols must be by a recognized authority in environmental testing, such as Municipal and Industrial Strategy for Abatement, Standard Methods for examination of Water and Wastewater, US EPA, ASTM, National Sanitation Foundation, etc.

Documented Experimental Design and Operating Conditions

The data collected to support the performance claim of the technology must be collected within appropriate ranges of key operating parameters, such as feed rate, feed characteristics, temperature, reagent dosages, hydraulic loading rates, etc. It is important to know which operating conditions are representative of the process and the typical ranges since these must be stated in the performance claim. A verified claim is only valid if the technology is operated within the operating conditions stated in the performance claim.

The experimental design must be documented prior to testing. This document defines acceptable values (or ranges) for each of the key operating conditions, data collection methodology and analytical methodology. This will ensure that data are collected in a rational and systematic manner.

The operating conditions during the testing must be monitored and documented to ensure that they stay within the operating ranges defined in the experimental design. Information must be provided on the actual key operating variables during the test and the methodology used to monitor and document these conditions.

The instruments used to measure the operating parameters must be calibrated regularly to ensure that the instruments are providing accurate, reliable readings and these calibrations must be documented.

Quality Assurance/Quality Control/Chain of Custody
Quality Assurance (QA) refers to a definitive plan for laboratory operation that specifies the measures used to produce data of known precision and reproducibility.

Quality Control (QC) refers to a set of measures within a sample analysis methodology to assure that the process is in control. Acceptable quality assurance/quality control (QA/QC) procedures must be used for sample collection and analysis. For sampling, QA/QC may include the use of blanks, spiked samples and replicate samples as well as inter-laboratory studies and use of SRMs.

Chain-of-custody refers to the ability to trace the possession and handling of the sample from the time of collection through analysis and final deposition to ensure the integrity of the process from sample collection to data reporting. Chain-of-custody reporting is used in routine control of sample flow, and in litigation if required. Acceptable chain-of-custody for sample analysis may include sample labels, sample seals, sample submission sheets, sample receipt log and assignment for analysis.

Analytical or Laboratory Protocols
The laboratory which analyzed the samples must be independent from the applicant, and accredited by a recognized certification agency for the specific parameters being analyzed. In Canada, acceptable laboratory accreditation must be earned from the Canadian Association of Environmental Analytical Laboratories (CAEAL) or an equivalent certification agency so designated by the Standards Council of Canada (SCC). This will ensure independent, accurate results.