Dynamics and Numerical Simulation of Contaminant Diffusion for a Non-Flushing Ecological Toilet

Zhonghua Zhang; Lingjie Zeng; Huixian Shi; Gukun Yang; Zhenjiang Yu; Wenjun Yin; Jun Gao; Lina Wang; Yalei Zhang; Xuefei Zhou

doi:10.3390/en14227570

Energies (Nov 2021)

Dynamics and Numerical Simulation of Contaminant Diffusion for a Non-Flushing Ecological Toilet

Zhonghua Zhang,
Lingjie Zeng,
Huixian Shi,
Gukun Yang,
Zhenjiang Yu,
Wenjun Yin,
Jun Gao,
Lina Wang,
Yalei Zhang,
Xuefei Zhou

Affiliations

Zhonghua Zhang: National Engineering Research Center of Protected Agriculture, New Rural Development Institute of Tongji University, Shanghai 200092, China
Lingjie Zeng: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Huixian Shi: National Engineering Research Center of Protected Agriculture, New Rural Development Institute of Tongji University, Shanghai 200092, China
Gukun Yang: National Engineering Research Center of Protected Agriculture, New Rural Development Institute of Tongji University, Shanghai 200092, China
Zhenjiang Yu: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Wenjun Yin: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Jun Gao: School of Mechanical Engineering, Tongji University, Shanghai 200092, China
Lina Wang: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
Yalei Zhang: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Xuefei Zhou: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China

DOI: https://doi.org/10.3390/en14227570
Journal volume & issue: Vol. 14, no. 22
p. 7570

Abstract

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The poor indoor air quality (IAQ) of severely polluted toilets is associated with increased risk of severe disease. This study aimed to evaluate the overall IAQ according to the contaminant removal efficiency, volume average concentration, and breathing zone control level. The characteristics of contaminant transmission in a non-flushing ecological toilet (NFET) were analyzed using the computational fluid dynamics (CFD) methodology, and the proposed model was further validated based on experimental measurements. Both an orthogonal experimental design and CFD were used to analyze factors such as exhaust fan position (EFP), air change rate per hour (ACH), natural vent location (NVL), and grid height (G-h). The EFP and ACH were demonstrated to be the dominant factors affecting the IAQ, whereas NVL and G-h were found to play key roles. Single-factor analysis based on the significance levels of the ACH, EFP, and NVL was conducted using the CFD methodology to define three exhaust behaviors—namely, “ineffective”, “enhanced”, and “excessive”. These results provide key insights that may be used to improve the IAQ of NFETs.

Published in Energies

ISSN: 1996-1073 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology
Website: http://www.mdpi.com/journal/energies

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