DEVELOPMENT OF A RAPID ATP ANALYSIS METHOD: BIOMASS GROWTH ATP METHOD FOR UV DISINFECTION MONITORING IN WASTEWATER TREATMENT

Abstract

Adenosine triphosphate (ATP) analysis is gaining popularity as a robust method to quantify microbial content in water supplies and wastewater treatment processes. ATP testing provides cost effective microbial analysis results in a matter of minutes in the laboratory or the field. A challenge with ATP monitoring is that an Ultraviolet (UV) dose sufficient to cause a significant reduction in culturability yields little to no reduction in ATP. To date, few studies have been conducted to investigate the possible techniques that enable the application of ATP assays in assessing the effectiveness of UV disinfection.

The objective of this study was to develop a pre-treatment technique prior to ATP assay that can detect differences in cellular ATP (cATP) between pre and post UV treated wastewater in a single shift (<8hrs) to improve compliance monitoring and disinfection performance. The research approach involved incubating both untreated and irradiated samples in a suitable growth environment to accelerate bacterial growth prior to ATP analysis. The treatment efficacy was determined by the disparity in increase of cATP growth.

A robust Biomass Growth ATP Method (optimum chemical reagent, optimum incubation temperature, 4 hours) has been developed to test UV disinfection efficacy in municipal wastewater treatment. The response of the method indicated a significant direct correlation to the microbial population reduction observed in HPC method (R2A agar, 28℃, 7days) for both pure E. coli culture and secondary effluent. The Biomass Growth ATP Method was then tested in field samples from three wastewater treatment plants (WWTPs) to validate its practicality. The result that Biomass Growth ATP Method could detect a 1-2-order of magnitude of microbial inactivation implied a prospective application of this new method in WWTPs with high microbial loading rates to evaluate UV disinfection performance.