Sustainable treatment of primary and secondary effluent by algal-bacterial flocculent biomass in raceway ponds

Styliani E Biliani; Ioannis D Manariotis

doi:10.1016/j.jenvman.2023.118167

Sustainable treatment of primary and secondary effluent by algal-bacterial flocculent biomass in raceway ponds

J Environ Manage. 2023 Oct 1:343:118167. doi: 10.1016/j.jenvman.2023.118167. Epub 2023 May 23.

Authors

Styliani E Biliani¹, Ioannis D Manariotis²

Affiliations

¹ Environmental Engineering Laboratory, Department of Civil Engineering, University of Patras, 265 04, Patras, Greece.
² Environmental Engineering Laboratory, Department of Civil Engineering, University of Patras, 265 04, Patras, Greece. Electronic address: idman@upatras.gr.

PMID: 37229856
DOI: 10.1016/j.jenvman.2023.118167

Abstract

Two 5.5-L raceway open ponds were used to evaluate the removal of organic material and nutrients from wastewater. Algal-bacterial flocs were placed in the ponds to treat primary and secondary effluent. The organic loading rate ranged from 29 to 95 and 9 to 38 g sCOD m^-3 d^-1 for the reactor fed with primary and secondary effluent, respectively. The hydraulic retention time (HRT) gradually decreased in both reactors from 5.5 to 2.2 d during a period of 21 days, and after that, both reactors operated at an HRT of 1.1 d. A high biomass concentration of around 2.2 g L^-1 was sustained using primary and secondary effluent after 130 days. The biomass, developed with both substrates was very active and completely removed organic material and nutrients in less than 12 h. The algal-bacteria biomass had excellent settling properties and could settle in less than 10 min.

Keywords: Algae-bacteria flocs; Biomass production; Nutrient removal; Wastewater treatment; Μicroalgae.

MeSH terms

Bacteria
Biomass
Microalgae*
Ponds / microbiology
Waste Disposal, Fluid*