Cultivation of Chlorella vulgaris in a Light-Receiving-Plate (LRP)-Enhanced Raceway Pond for Ammonium and Phosphorus Removal from Pretreated Pig Urine

Abstract

Fresh pig urine is unsuitable for microalgae cultivation due to its high concentrations of NH4+-N, high pH and insufficient magnesium. In this study, fresh pig urine was pretreated by dilution, pH adjustment, and magnesium addition in order to polish wastewater and produce microalgae biomass. Chlorella vulgaris was cultured in an in-house-designed light-receiving-plate (LRP)-enhanced raceway pond to treat the pretreated pig urine in both batch and continuous mode under outdoor conditions. NH4+-N and TP in wastewater were detected, and the growth of C. vulgaris was evaluated by chlorophyll fluorescence activity as well as biomass production. Results indicated that an 8-fold dilution, pH adjusted to 6.0 and MgSO4·7H2O dosage of 0.1 mg·L−1 would be optimal for the pig urine pretreatment. C. vulgaris could stably accumulate biomass in the LRP-enhanced raceway pond when cultured by both BG11 medium and the pretreated pig urine. About 1.72 g·m−2·day−1 of microalgal biomass could be produced and 98.20% of NH4+-N and 68.48% of TP could be removed during batch treatment. Hydraulic retention time of 7-9d would be optimal for both efficient nutrient removal and microalgal biomass production during continuous treatment.

Wastewater treatment using Scenedesmus almeriensis: effect of operational conditions on the composition of the microalgae-bacteria consortia

“…Reasons for these values could be a relatively high N-NH4 + concentration or the potential presence of toxins or other compounds present in wastewater that affect microalgal growth. This hypothesis is supported with previous results that reported Fv/Fm values in the range 0.4-0.5 when microalgae were produced using pre-treated pig urine (Zou et al 2020) or wastewater (Sánchez Zurano et al 2020). Low Fv/Fm values can also be partially attributed to the fact that microalgae were produced in summer and that Fv/Fm values can be lower during this season because of photoinhibition caused by (reversible) damage to key PSII components (Acién Fernández et al 2003).…”

Evaluation of Scenedesmus rubescens for Lipid Production from Swine Wastewater Blended with Municipal Wastewater

“…In Korea, more than 32 million tons of swine wastewater were generated in 2015 [10]. In general, swine wastewaters are rich in organic matter, nitrogen, and phosphorus [11].…”