Evaluation of microalgae's (Chlorella sp. and Synechocystis sp.) pollutant removal property: Pig effluent as a live stock discharge

Abstract

The ability of microalgae to remove nitrogen and phosphorus from wastewater has been used in recent years as an alternative treatment for discharges from livestock slurry, which generate a negative environmental impact on vulnerable ecosystems. With this background and the feasibility of using microalgae, we have evaluated the effect of Chlorella sp. and Synechocystis sp., in removing contaminants from the pig manure collected from El Prado ESPE. Slurry samples were collected, filtered and autoclaved, and the supernatant was further diluted to three different concentrations of 40%, 60% and 80%. The microalgal growth and pollutants removal property was evaluated up to 15 days in batch culture. The cell density was determined by counting in a Neubauer hemocytometer, and the pollutants removal was analyzed by standard colorimetric methods. The microalgae Chlorella sp. showed a maximum cell growth of 1.70 ± 0.09 x10 7 cells/mL at 60% effluent concentration on day 6. While Synechocystis sp. showed a maximum growth of 1.04 ± 0.05 x10 7 cells/mL, at 60% concentration on day 9. On the other hand, there exists a competition when microalgae used as a consortium. The cell growth of Chlorella sp. was higher at all concentrations compared to Synechocystis sp.. Overall, efficiency of pollutant removal were between 40% and 90%, which demonstrate the feasibility of using microalgae in tertiary swine wastewater treatment.

Removal of organic matter during adaptation of Nannochloropsis oculata in livestock waste

“…On the other hand, in the photobioreactors with 70% inoculum, a significant growth of microalgae was observed, from 4.96 x10 7 on day 0 to 1.4 x10 8 cells/ml on day 10. The concentrations obtained were higher than those reported by Pachacama et al (2016), who obtained Chlorella sp. (1.7 x10 7 cells/ml) and Synechocystis sp.…”

Growth Performance, Biochemical Composition and Nutrient Recovery Ability of Twelve Microalgae Consortia Isolated from Various Local Organic Wastes Grown on Nano-Filtered Pig Slurry

“…For example, Synechocystis co-cultivated in consortia with Chlorella sp. could have promoted cell growth [26], explaining the good growth performance of AC_10.…”

Optimisation of Secondary Biological Treatment Using Symbiosis of Micro-Algae and Bacteria

“…However, very high ammonium concentrations can also have negative effects on algae growth and several researchers have reported the concentration from which the ammonium can be considered toxic to many algae species in distinct conditions. 2) Biotic factors -Pathogens (bacteria, viruses), competition between cyanobacteria and algae 3) Operating factors -Agitation, renewal rate, addition of bicarbonate and harvesting frequency 3.4 Determination of micro-algae growth [5]: Cell number was determined by cell count with under the light microscope. Cell density was determined using the following equation: DC =N*10^4*FD Where N is the average number of cells in relation to quadrants used in 104 is the conversion factor of 0.1 μL to 1 mL and FD is the dilution factor.…”