Understanding Microbial Loads in Wastewater Treatment Works as Source Water for Water Reuse.

Jill Hoelle,Nichole E. Brinkman,Laura Boczek,Jatin H. Mistry,Eric N. Villegas,Scott P. Keely,Michael W. Ware,Hodon Ryu,Yao Addor

doi:10.3390/w13111452

Abstract

Facing challenges in water demands and population size, particularly in the water-scarce regions in the United States, the reuse of treated municipal wastewater has become a viable potential to relieve the ever-increasing demands of providing water for (non-)potable use. The objectives of this study were to assess microbial quality of reclaimed water and to investigate treatability of microorganisms during different treatment processes. Raw and final treated effluent samples from three participating utilities were collected monthly for 16 months and analyzed for various microbial pathogens and fecal indicator organisms. Results revealed that the detectable levels of microbial pathogens tested were observed in the treated effluent samples from all participating utilities. Log10 reduction values (LRVs) of Cryptosporidium oocysts and Giardia cysts were at least two orders of magnitude lower than those of human adenovirus and all fecal indicator organisms except for aerobic endospores, which showed the lowest LRVs. The relatively higher LRV of the indicator organisms such as bacteriophages suggested that these microorganisms are not good candidates of viral indicators of human adenovirus during wastewater treatment processes. Overall, this study will assist municipalities considering the use of wastewater effluent as another source of drinking water by providing important data on the prevalence, occurrence, and reduction of waterborne pathogens in wastewater. More importantly, the results from this study will aid in building a richer microbial occurrence database that can be used towards evaluating reuse guidelines and disinfection practices for water reuse practices.

Highlights

Introduction published maps and institutional affilWater scarcity is becoming a global problem directly impacting drinking water quality and quantity throughout the United States (US), especially in regions with limited source waters
Microbial pathogens such as Cryptosporidium, Giardia, and infectious human adenovirus were monitored from a total of 47 influents and 47 final treated effluent samples
Various equivalent sample volume analyzed (ESVA) among samples were observed, and this variance was mainly caused by differences in the immunomagnetic separation (IMS) processing volume that is directly related to the amount of solids in the water samples

Summary

Introduction

Introduction published maps and institutional affilWater scarcity is becoming a global problem directly impacting drinking water quality and quantity throughout the US, especially in regions with limited source waters. In recent years the United States (US) has been experiencing longer, more frequent, and more severe drought periods, especially in the southwestern regions [1]. To address this challenge of continued high demand for high-quality water, especially for potable use, many communities, water resource managers, and government agencies in the US and worldwide are turning to various alternative solutions that are more sustainable, cost-effective, and responsive to changing community demands and climate fluctuations [2,3]. The reuse of treated municipal wastewater has the potential to relieve the ever-increasing demands of providing fresh water, and to provide several beneficial purposes.

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