Wastewater treatment by local microalgae strains for CO2 sequestration and biofuel production

Abstract

Currently, the scientific community is keenly working on environmental-friendly processes for the production of clean energy and sustainable development. The study was conducted to cultivate microalgae in raw institutional wastewater for water treatment, enriched production of biomass and CO 2 sequestration. The strains which were used in this study are Scenedesmus sp. and Chlorella sp. which were isolated from Kallar Kahar Lake, Pakistan. Both strains were cultivated in synthetic growth medium (Bold's Basal Medium) to enhance biomass production. Afterward, microalgae cultures were inoculated in wastewater sample in mixotrophic mode under ambient conditions. The impurities in wastewater were successfully removed from the original sample by the 7th day of operation. COD 95%, nitrate 99.7% and phosphate 80.5% were removed by applying Scenedesmus sp. Meanwhile, Chlorella sp. reduced 84.86% COD, 98.2% nitrate and 70% phosphate, respectively. Interestingly, sulfates were removed from wastewater completely by both strains. Besides being useful in wastewater remediation, these microalgae strains were subsequently harvested for lipid extraction and potential biofuel production was determined. Therefore, the applied method is an environmentally safe, cost-effective and alternative technology for wastewater treatment. Furthermore, the achieved biomass through this process can be used for the production of biofuels.

Evaluation of gradual adaptation of mixed microalgae consortia cultivation using textile wastewater via fed batch operation

“…Over the literature review, Wang et al (2017) achieved 75.7, 62.5 and 38.4% for TN, TP and COD removal efficiency by running under batch condition [ 17 ]. With the similar pattern, Ansari et al [ 16 ] studied two different species of microalgae using institutional wastewater achieved 98.2 and 99.7, 70.5 and 80.5, and 84.86 and 95% of TN, TP and COD removal efficiency for Chlorella sp. and Scenedesmus sp.…”

“… Operation Substrate Microalgae species Biomass productivity (g.L −1 .d −1 ) Growth rate (d −1 ) Removal efficiency Reference COD (%) TN (%) TP (%) Batch Institutional wastewater Chlorella sp. – 0.29 84.86 98.2 70.5 [ 16 ] Batch Institutional wastewater Scenedesmus sp. – 0.33 95 99.7 80.5 [ 16 ] Batch Anaerobic digested dairy manure Chlorella sp.…”

“… – 0.29 84.86 98.2 70.5 [ 16 ] Batch Institutional wastewater Scenedesmus sp. – 0.33 95 99.7 80.5 [ 16 ] Batch Anaerobic digested dairy manure Chlorella sp. – 0.41 38.4 75.7 62.5 [ 17 ] Batch Textile waster Mixed microalgae species – 0.42 78.78 93.3 100 [ 3 ] Semi-continuous Livestock wastewater Botyococcus braunii 0.2 – – 96 85 [ 18 ] Sequencing batch reactor Livestock wastewater Botyococcus braunii 0.315 0.2 – 83.2 94.1 [ 7 ] Fed batch reactor Textile wastewater Mixed microalgae species 0.49 1.24 70.7 …”

Sustainable Bioenergy from Biofuel Residues and Waste

“…The findings demonstrated algal biomass dewatering was achieved by gravity sedimentation, chemical flocculation, and centrifugation. The solid algal residue resulting from biodiesel process was used as raw material for pellet manufacturing Ansari et al (2017). examined the possibility to cultivate microalgae in raw institutional wastewater for water treatment, enriched production of biomass and CO2 sequestration.…”

Ammonium and phosphate removal using batch laboratory cultures by microalgae and cyanobacteria isolated from Costa Rica water bodies

“…Cyanobacteria, free or immobilized in a matrix, have also been investigated (De la Noüe, Lessard, & Proulx, 1993;Chevalier, Proulx, Lessard, Vincent, & de la Noüe, 2000;Olguín, Galicia, Mercado, & Pérez, 2003). Other potential use of the green microalgae, it is related with the biomass generated by bioremediation procedures, which can be coupled to biotechnological applications like biogas, biofuel or biofertilizers production (Ansari, Hussain, Nawar, Qayyum, & Ali, 2017;Diniz, Silva, Araújo, & Chaloub, 2017).…”