Method Validation Case Study: DPD Legacy Method Applied to Peracetic Acid Collaborative Efforts to Improve Environmental Monitoring

Collaborative Efforts to Improve Environmental Monitoring
Oral Presentation

Prepared by

Contact Information: jcarpent@chemetrics.com; 540-788-9026


ABSTRACT

Interest in developing a standard method for the analysis of peracetic acid (PAA) is part of a larger effort to advance PAA as a disinfectant in wastewater treatment. In 2017, a workgroup of PAA stakeholders representing EPA’s Office of Water/Engineering and Analysis Division (EAD), POTW operations personnel, engineering consulting firms, PAA suppliers, and test kit vendors began collaborating to establish a new method for the analysis of PAA based on the well-established N-N-diethyl–p-phenylenediamine (DPD) method, for publication in Section 4000 of Standard Methods.
As part of the collaborative efforts, the stakeholders designed a method validation plan that considered guidance from resources beyond Standard Methods Section 1040 C. Collaborative Testing. These included ASTM D2777-13 Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on water; ASTM E691-18 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method, and EPA’s “Protocol for Review and Validation of New Methods for Regulated Organic and Inorganic Analytes in Wastewater Under EPA’s Alternate Test Procedure Program.”
Bulk wastewater samples solicited from publicly owned treatment plants were used to prepare nine test samples for the validation study. Test kit vendors provided materials and equipment. Because of the inherent difficulties in shipping samples of a labile disinfectant to multiple locations, the workgroup assembled seven people to serve as analysts and perform the study at a single location, under the direction of the study monitors, who prepared and distributed the blind test samples.
This presentation will discuss the challenges wastewater oxidant demand poses to study design and will highlight the application of the Youden Pair statistical approach to characterize random and systematic sources of error.