Development of monitored tunable biodosimetry for fluence validation in an ultraviolet disinfection reactor

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Electrical energy consumption per order (E EO ) is an important figure-of-merit for the selection and optimization of ultraviolet (UV)-based advanced oxidation processes (UV-AOPs). However, E EO applications are limited by the lack of an accurate and facilitative evaluation method because E EO presents reactor property dependence. In this study, we developed an E EO prediction method for multiscale UV-AOP reactors for micropollutant removal in water. The method utilized the reaction rate constants determined in a reference reactor (e.g., mini-fluidic photoreaction system), complemented by a scale-up method that clarified the dependence of E EO on reactor properties. The predicted results of various UV-AOPs were verified experimentally in four bench/ pilot-scale reactors in laboratory and a full-scale flow-through reactor (FFR) in field using sulfamethazine as a model micropollutant. For example, E EO values of 0.105 and 0.058 kWh m −3 order −1 were predicted in the FFR at H 2 O 2 doses of 5 and 10 mg L −1 , respectively, which generally agreed with verification results. Additionally, the developed method could assist the identification of appropriate reactors in the laboratory for E EO measurements, providing a valuable supplement for the E EO prediction in practice. The developed method presents acceptable accuracy, convenience, and low cost, which would significantly facilitate E EO evaluations for practical UV-AOP applications.

Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Electrical Energy Consumption of Multiscale UV-AOP Reactors for Micropollutant Removal in Drinking Water: Facilitated Prediction by Reaction Rate Constants Measured on a Mini-Fluidic Photoreaction System

Lou

Sun

et al. 2023

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“…However, without protection of the quartz sleeve that helps stabilize the lamp surface temperature, the fluctuation in lamp output can induce an enlarged uncertainty in bench-scale kinetic studies. 21,22 In addition, it is difficult to determine accurately the photon fluence because of the nonuniform distribution of photon fluence rate (PFR) in batch VUV/UV reactors. Therefore, it is desirable to have a new bench-scale VUV/UV apparatus for relevant photoreaction studies.…”

Section: −20mentioning

confidence: 99%

“…Moreover, because the VUV only comprises a small fraction of the total lamp output (i.e., about 5–8% of the UV output) and has a low transmittance in air, quartz sleeves are not used in many batch VUV/UV reactors so as to maximize the VUV output. However, without protection of the quartz sleeve that helps stabilize the lamp surface temperature, the fluctuation in lamp output can induce an enlarged uncertainty in bench-scale kinetic studies. , In addition, it is difficult to determine accurately the photon fluence because of the nonuniform distribution of photon fluence rate (PFR) in batch VUV/UV reactors. Therefore, it is desirable to have a new bench-scale VUV/UV apparatus for relevant photoreaction studies.…”

Section: Introductionmentioning

confidence: 99%

VUV/UV/Chlorine as an Enhanced Advanced Oxidation Process for Organic Pollutant Removal from Water: Assessment with a Novel Mini-Fluidic VUV/UV Photoreaction System (MVPS)

Qiang

Hou

et al. 2016

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Vacuum ultraviolet (VUV) and ultraviolet (UV)/chlorine processes are regarded as two of many advanced oxidation processes (AOPs). Because of the similar cost of VUV/UV and UV lamps, a combination of VUV and UV/chlorine (i.e., VUV/UV/chlorine) may enhance the removal of organic pollutants in water but without any additional power input. In this paper, a minifluidic VUV/UV photoreaction system (MVPS) was developed for bench-scale experiments, which could emit both VUV (185 nm) and UV (254 nm) or solely UV beams with a nearly identical UV photon fluence. The photon fluence rates of UV and VUV output by the MVPS were determined to be 8.88 × 10 −4 and 4.93 × 10 −5 einstein m −2 s −1 , respectively. The VUV/UV/chlorine process exhibited a strong enhancement concerning the degradation of methylene blue (MB, a model organic pollutant) as compared to the total performance of the VUV/UV and UV/chlorine processes, although the photon fluence of the VUV only accounted for 5.6% of that of the UV. An acidic pH favored MB degradation by the VUV/ UV/chlorine process. The synergistic mechanism of the VUV/UV/chlorine process was mainly ascribed to the effective use of • OH for pollutant removal through formation of longer-lived secondary radicals (e.g.,• OCl). This study demonstrates that the new VUV/UV/chlorine process, as an enhanced AOP, can be applied as a highly effective and energy-saving technology for small-scale water and wastewater treatment.

“…The performance of a UV reactor is governed by the UV fluence or, more precisely, by the fluence distribution. The initial (nominal) fluence determination (as measured by biodosimetry) of an ex-factory UV reactor has been investigated by many researchers. − Fluence estimation during subsequent operation is often based on initial fluence and monitoring of flow rate, UVT, and conventional detector readings. Monitoring protocols based on this approach have been proposed and applied. − …”

Section: Introductionmentioning

confidence: 99%

On-Site Determination and Monitoring of Real-Time Fluence Delivery for an Operating UV Reactor Based on a True Fluence Rate Detector

Qiang

et al. 2017

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At present, on-site fluence (distribution) determination and monitoring of an operating UV system represent a considerable challenge. The recently developed microfluorescent silica detector (MFSD) is able to measure the approximate true fluence rate (FR) at a fixed position in a UV reactor that can be compared with a FR model directly. Hence it has provided a connection between model calculation and real-time fluence determination. In this study, an on-site determination and monitoring method of fluence delivery for an operating UV reactor was developed. True FR detectors, a UV transmittance (UVT) meter, and a flow rate meter were used for fundamental measurements. The fluence distribution, as well as reduction equivalent fluence (REF), 10th percentile dose in the UV fluence distribution (F), minimum fluence (F), and mean fluence (F) of a test reactor, was calculated in advance by the combined use of computational fluid dynamics and FR field modeling. A field test was carried out on the test reactor for disinfection of a secondary water supply. The estimated real-time REF, F, F, and F decreased 73.6%, 71.4%, 69.6%, and 72.9%, respectively, during a 6-month period, which was attributable to lamp output attenuation and sleeve fouling. The results were analyzed with synchronous data from a previously developed triparameter UV monitoring system and water temperature sensor. This study allowed demonstration of an accurate method for on-site, real-time fluence determination which could be used to enhance the security and public confidence of UV-based water treatment processes.