Use of a passive bioreactor to reduce water-borne plant pathogens, nitrate, and sulfate in greenhouse effluent

Abstract

The goal of this study was to evaluate the use of passive bioreactors to reduce water-borne plant pathogens (Pythium ultimum and Fusarium oxysporum) and nutrient load (NO- (3) and SO2- (4)) in greenhouse effluent. Sterilized and unsterilized passive bioreactors filled with a reactive mixture of organic carbon material were used in three replicates. After a startup period of 2 (sterilized) or 5 (unsterilized) weeks, the bioreactor units received for 14 weeks a reconstituted commercial greenhouse effluent composed of 500mg L-1 SO2- (4) and 300mg L-1 NO- (3) and were inoculated three times with P. ultimum and F. oxysporum (10(6) CFU mL(-1)). Efficacy in removing water-borne plant pathogens and nitrate reached 99.9% for both the sterilized and unsterilized bioreactors. However, efficacy in reducing the SO2- (4) load sharply decreased from 89% to 29% after 2 weeks of NO- (3)-supply treatment for the unsterilized bioreactors. Although SO2- (4) removal efficacy for the sterilized bioreactors did not recover after 4 weeks of NO- (3)-supply treatment, the unsterilized bioreactor nearly reached a similar level of SO2- (4) removal after 4 weeks of NO- (3)-supply treatment compared with affluent loaded only with SO2- (4), where no competition for the carbohydrate source occurred between the denitrification process and sulfate-reducing bacteria activity. Performance differences between the sterilized and unsterilized bioreactors clearly show the predominant importance of sulfate-reducing bacteria. Consequently, when sulfate-reducing bacteria reach their optimal activity, passive bioreactors may constitute a cheap, low-maintenance method of treating greenhouse effluent to recycle wastewater and eliminate nutrient runoff, which has important environmental impacts.

Keywords

Denitrification; Fusarium oxysporum; organic carbon; Pythium ultimum; sulfate reduction; sulfate-reducing bacteria

Published in

Journal of Environmental Science and Health, Part A
2013, volume: 48, number: 13, pages: 1740-1747
Publisher: TAYLOR & FRANCIS INC

SLU Authors

• Alsanius, Beatrix

  • Horticulture, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG3 Good health and well-being
SDG6 Clean water and sanitation
SDG12 Responsible consumption and production

UKÄ Subject classification

Horticulture

Publication identifier

• DOI: https://doi.org/10.1080/10934529.2013.815569

Permanent link to this page (URI)

https://res.slu.se/id/publ/55135