Using submersible fluorescence sensors to track the removal of organic matter in decentralized wastewater treatment systems (DEWATS) in real time.

A Bigelow,B Pietruschka,C Buckley,M Palomo,N Mladenov

doi:10.2166/wst.2017.573

Abstract

Decentralized wastewater treatment systems (DEWATS) using anaerobic treatment are increasingly being considered for wastewater treatment with options for non-potable water reuse at the community scale. One challenge for ensuring performance and reliability of DEWATS is the lack of suitable on-site sensors to monitor failure or contamination events. In this study, the aim was to use in situ fluorescence sensors to track the performance of a DEWATS, consisting of an anaerobic baffled reactor (ABR) coupled to anaerobic filter (AF) and constructed wetland (CW) treatment processes. A submersible in situ fluorometer equipped with tryptophan (TRP) and chromophoric dissolved organic matter (CDOM) sensors was deployed in each chamber of the ABR-AF-CW system, and results showed that TRP fluorescence was preferentially removed over CDOM fluorescence throughout the system. Significant relationships between TRP fluorescence and chemical oxygen demand (COD) also suggested that TRP fluorescence could be used as a surrogate for COD and soluble COD concentrations. Strong agreement between results obtained from the 1D in situ fluorometer and those obtained from a 3D benchtop fluorometer lends further support to the use of in situ fluorescence sensors to track DEWATS performance.

Highlights

Worldwide, population growth has outpaced infrastructure growth in many urban settings, leaving communities without adequate water and sanitation services
Deviations of chemical oxygen demand (COD) concentrations measured at the anaerobic baffled reactor (ABR) inlet with those measured in the anaerobic filter (AF) outlet from January to December 2015 (Figure 3)
We found that TRP and chromophoric dissolved organic matter (CDOM) fluorescence profiles along the ABR-AF-constructed wetland (CW) system showed close agreement for both in situ and benchtop instruments (Figure 5(a) and 5(b))

Summary

Introduction

Population growth has outpaced infrastructure growth in many urban settings, leaving communities without adequate water and sanitation services There is both the challenge of providing formalized water and wastewater treatment for growing populations and the burden of replacing aging infrastructure. Anaerobic baffled reactor (ABR) technology, originally developed by McCarty at Stanford (McCarty ) is the core module of DEWATS that has recently gained attention for the treatment of domestic wastewater (Foxon et al ; Hahn & Figueroa ). Anaerobic wastewater treatment, such as secondary treatment using ABR systems, has low maintenance and energy requirements and generates a fraction of the residuals compared to aerobic systems, resulting in reduced sludge disposal.

Objectives

Methods

Results

Conclusion