Enhancement of nutrient removal from swine wastewater digestate coupled to biogas purification by microalgae Scenedesmus spp.

Abstract

This work investigated the effects of swine wastewater-derived biogas on microalgae biomass production and nutrient removal rates from piggery wastewater concomitantly with biogas filtration. Photobioreactors with dominant Scenedesmus spp. were prepared using non-sterile digestate and exposed to different photoperiods. In the presence of biogas and autotrophic conditions microalgae yield of 1.1±0.2 g L(-1) (growth rate of 141.8±3.5 mg L(-1) d(-1)) was obtained leading to faster N-NH3 and P-PO4(3-) assimilation rate of 21.2±1.2 and 3.5±2.5 mg L(-1) d(-1), respectively. H2S up to 3000 ppmv was not inhibitory and completely removed. Maximum CO2 assimilation of 219±4.8 mg L(-1) d(-1) was achieved. Biological consumption of CH4 up to 18% v/v was verified. O2 up to 22% v/v was controlled by adding acetate to exacerbate oxygen demand by microorganisms. Microalgae-based wastewater treatment coupled to biogas purification accelerates nutrient removal concomitantly producing valuable biomass and biomethane.

Elimination of Antibiotic Multi-Resistant Salmonella Typhimurium from Swine Wastewater by Microalgae-Induced Antibacterial Mechanisms

“…These values were within the higher growth rates reported for Scenedesmus sp. in swine wastewaters [10,17]. The biomass increase measured in both PBRs treatments were very similar (p<0.05), with maximum microalgal concentration of 265 ± 3.9 mg-DW L -1 observed at 72 h ( Figure 1).…”

“…The measured DO concentrations were above solubility levels (i.e., 8.3 mg L -1 at 1 atm and 25°C) ( Figure 1). Oxygen saturation is normally found in ponds or photobioreactors due to high microalgae growth rate and associated photosynthetic activities [10,17,21]. The high pH values measured in the PBRs without pH adjustment seemed to play a major role on the inactivation of S. Typhimurium during Scenedesmus spp.…”

“…Scenedesmus spp. was the dominant microalgae in the PBRs as described elsewhere [9,10]. The strain was isolated and deposited in the collection of photosynthetic microorganisms for Agroenergy Research at Embrapa (Brasília, DF, Brazil) under access number Embrapa LBA#31 (IAN193.096).…”

“…Phycoremediation has been considered as an efficient tertiary treatment method to reduce organic compounds and nutrients from wastewaters [9][10][11][12]. Some microalgae produce a wide variety of antibacterial substances that can inhibit or kill pathogens [13,14].…”

Algal–bacterial synergy in treatment of winery wastewater

“…Numerous studies exist on the use of algae to treat various types of wastewaters including those from dairies, 7 piggeries, 8 wineries, 9 slaughterhouses, 10 and municipalities. 11,12 The fact that algae can grow successfully on such chemically diverse wastewaters indicates the potential scalability of algal wastewater treatment.…”