Screening of microalgae for integral biogas slurry nutrient removal and biogas upgrading by different microalgae cultivation technology

Abstract

The microalgae-based technology has been developed to reduce biogas slurry nutrients and upgrade biogas simultaneously. In this work, five microalgal strains named Chlorella vulgaris, Scenedesmus obliquus, Selenastrum capricornutum, Nitzschia palea, and Anabaena spiroides under mono- and co-cultivation were used for biogas upgrading. Optimum biogas slurry nutrient reduction could be achieved by co-cultivating microalgae (Chlorella vulgaris, Scenedesmus obliquus, and Nitzschia palea) with fungi using the pelletization technology. In addition, the effects of different ratio of mixed LED light wavelengths applying mixed light-emitting diode during algae strains and fungi co-cultivation on CO2 and biogas slurry nutrient removal efficiency were also investigated. The results showed that the COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) removal efficiency were 85.82 ± 5.37%, 83.31 ± 4.72%, and 84.26 ± 5.58%, respectively at red: blue = 5:5 under the co-cultivation of S. obliquus and fungi. In terms of biogas upgrading, CH4 contents were higher than 90% (v/v) for all strains, except the co-cultivation with S. obliquus and fungi at red: blue = 3:7. The results indicated that co-cultivation of microalgae with fungi under mixed light wavelengths treatments was most successful in nutrient removal from wastewater and biogas upgrading.

Effects of influent C/N ratios and treatment technologies on integral biogas upgrading and pollutants removal from synthetic domestic sewage

“…Fungi and bacteria can also have strong degradation abilities for certain wastewater contaminants and can be associated with microalgae to form immobilization systems of algal-fungal culture or algal-bacterial culture with multiple functions. The advantages of these associations in wastewater treatment are: (i) improved collection of biomass from wastewaters, (ii) easily recycled and manipulated consortia, (iii) improved features of microalgae such as thermal stability and productivity, and (iv) harvestable bioresource from proliferated microalgae biomass 19 , 21 , 22 . The use of biogas and sewage as raw materials can not only output high-grade biogas through the microalgae photosynthesis to assimilate carbon dioxide, but also can purify sewage by accumulating C, N, and P in sewage with microalgae.…”

Fungal Contamination in Microalgal Cultivation: Biological and Biotechnological Aspects of Fungi-Microalgae Interaction

“…The fungi-microalgae binary system has been adopted for several scopes. Since wastewaters pose a great risk to human health and ecosystems, as they carry many toxic substances, the fungi-microalgae co-culture was recently considered as a viable approach for their treatments and remediation [ 149 ]. In water, as previously mentioned, inorganic carbon is mainly present in the form of HCO − 3 that microalgae can actively absorb and convert directly into CO 2 [ 146 ].…”

Hybrid Dissolved-Oxygen and Temperature Sensing: A Nanophotonic Probe for Real-Time Monitoring of Chlorella Algae

“…For the last century, the growing concern of global warming and the energy crisis has led to significant investigations into the identification and development of sustainable energy sources. Microalgae are a promising candidate for future biofuels, since they are efficient in converting CO 2 gas into carbon-rich lipids, which are a precursor to biodiesel fuel [ 24 , 25 , 26 , 27 ]. In addition, microalgae-based processes for biological nutrient removal (BNR) in wastewater have been introduced as an economically and environmentally alternative method to the conventional processes, because they can utilize nutrients of wastewater and use CO 2 from greenhouse gases for photosynthesis [ 28 ].…”