Short and long-term experiments on the effect of sulphide on microalgae cultivation in tertiary sewage treatment

Abstract

Microalgae cultivation appears to be a promising technology for treating nutrient-rich effluents from anaerobic membrane bioreactors, as microalgae are able to consume nutrients from sewage without an organic carbon source, although the sulphide formed during the anaerobic treatment does have negative effects on microalgae growth. Short and long-term experiments were carried out on the effects of sulphide on a mixed microalgae culture. The short-term experiments showed that the oxygen production rate (OPR) dropped as sulphide concentration increased: a concentration of 5mgSL reduced OPR by 43%, while a concentration of 50mgSL came close to completely inhibiting microalgae growth. The long-term experiments revealed that the presence of sulphide in the influent had inhibitory effects at sulphide concentrations above 20mgSL in the culture, but not at concentrations below 5mgSL. These conditions favoured Chlorella growth over that of Scenedesmus.

Growth pattern of Chlorella vulgaris and Arthrospira platensis using CO2 in biogas from anaerobic digestion of tofu wastewater: A preliminary study

“…Biogas used in this research contained 2,000 ppm H2S (Table 1); previous results show that H2S was an indirect source of sulfur but can also inhibit at concentrations higher than 200 ppm [14]. Other researchers reported that H2S presence in biogas did not affect CO2 removal efficiency; 98% CO2 removal was IOP Publishing doi:10.1088/1755-1315/1143/1/012016 5 achieved in the systems with and without injection of H2S [15]. Hydrogen sulfide is produced in anaerobic digestion by sulfate-reducing bacteria and is present at 0-10,000 ppm, depending on the starting material and inoculum used.…”

Anaerobic membrane bioreactors for wastewater treatment: Challenges and opportunities

“…Typical nitrification/denitrification or anammox processes can eliminate nitrogen in AnMBR permeates. Integrating microalgae with AnMBRs can remove nitrogen or might be used for biofuel production (Gonzalez‐Camejo et al, 2018; González‐Camejo et al, 2017), when target wastewater contains high nutrients concentration. The integration of AnMBR with microalgae cultivation and biofuel production can achieve both COD/BOD and nutrients removal and may produce high quality effluent for water reuse and potential system closure.…”

Production of microalgal external organic matter in a Chlorella-dominated culture: influence of temperature and stress factors

“…3 The AnMBR effluent was aerated prior o being fed to the PBRs in order to oxidise the sulphide to sulphate, due to its toxic nature to microalgae. 44 The organic matter loading was mainly inert (Table A.1), thus boosting photoautotrophic metabolism typical of microalgae. 45 However, the presence of EOM in the microalgae culture made the soluble COD concentration to be 144 ± 69 mg COD•L -1 .…”