Optimization of rotational speed and hydraulic retention time of a rotational sponge reactor for sewage treatment

Choolaka Hewawasam; Norihisa Matsuura; Yuya Takimoto; Masashi Hatamoto; Takashi Yamaguchi

doi:10.1016/j.jenvman.2018.05.046

Optimization of rotational speed and hydraulic retention time of a rotational sponge reactor for sewage treatment

J Environ Manage. 2018 Sep 15:222:155-163. doi: 10.1016/j.jenvman.2018.05.046. Epub 2018 May 26.

Authors

Choolaka Hewawasam¹, Norihisa Matsuura², Yuya Takimoto³, Masashi Hatamoto⁴, Takashi Yamaguchi⁵

Affiliations

¹ Department of Energy and Environmental Science, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata, Japan.
² Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma, Kanazawa, Ishikawa, Japan. Electronic address: matsuura@se.kanazawa-u.ac.jp.
³ Department of Science of Technology Innovation, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata, Japan.
⁴ Top Runner Incubation Center for Academia-Industry Fusion, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata, Japan.
⁵ Department of Energy and Environmental Science, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata, Japan; Department of Science of Technology Innovation, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata, Japan. Electronic address: ecoya@vos.nagaokaut.ac.jp.

PMID: 29843088
DOI: 10.1016/j.jenvman.2018.05.046

Abstract

A rotational sponge (RS) reactor was proposed as an alternative sewage treatment process. Prior to the application of an RS reactor for sewage treatment, this study evaluated reactor performance with regard to organic removal, nitrification, and nitrogen removal and sought to optimize the rotational speed and hydraulic retention time (HRT) of the system. RS reactor obtained highest COD removal, nitrification, and nitrogen removal efficiencies of 91%, 97%, and 65%, respectively. For the optimization, response surface methodology (RSM) was employed and optimum conditions of rotational speed and HRT were 18 rounds per hour and 4.8 h, respectively. COD removal, nitrification, and nitrogen removal efficiencies at the optimum conditions were 85%, 85%, and 65%, respectively. Corresponding removal rates at optimum conditions were 1.6 kg-COD m^-3d^-1, 0.3 kg-NH₄⁺-N m^-3d^-1, and 0.12 kg-N m^-3d^-1. Microbial community analysis revealed an abundance of nitrifying and denitrifying bacteria in the reactor, which contributed to nitrification and nitrogen removal.

Keywords: Hydraulic retention time; Optimization; Rotational speed; Rotational sponge reactor; Sewage treatment.

MeSH terms

Bacteria
Bioreactors*
Nitrification
Nitrogen* / chemistry
Nitrogen* / isolation & purification
Sewage*
Waste Disposal, Fluid

Substances

Sewage
Nitrogen