Evaluation of Chlorella sorokiniana isolated from local municipal wastewater for dual application in nutrient removal and biodiesel production.

The isolated microalga Chlorella sorokiniana BENHA721_ABO4 was grown in Bold's basal medium (BBM) as a control, municipal wastewater (WW), and wastewater enriched with BBM elements (WW+). Cultivation in WW+ showed the highest cell number which represented 25.3 and 47.3% over that grown in WW and BBM, respectively. However, rapid growth in WW+ was accompanied by significant reduction in lipid content. Due to lipid accumulation in WW, it showed the maximum significant lipid productivity of 16.2 mg L-1 day-1. Microalgae cultivation in WW for 10 days showed 74.2, 83.3, and 78.0% removal efficiency for NO3-N, NH3-N and TP, respectively. In addition, growth in WW significantly reduced polyunsaturated fatty acids by 36.0% with respect to BBM in favor of monounsaturated fatty acids. The present results confirmed that C. sorokiniana isolate BENHA721_ABO4 grown in secondary effluent municipal wastewater offers real potential for future application in wastewater treatment and biodiesel production.

Influence of alum on cyanobacterial blooms and water quality of earthen fish ponds.

Eruption of blue-green algal blooms occurs frequently in eutrophic lakes and fish ponds, with associated unpleasant odor and horrid scums. In the present study, we conducted a pre-test experiment in 3 m(3) outdoor concrete ponds to determine the optimum concentration of aluminum sulfate (alum) required for reduction of the cyanobacterial blooms without negative effect on fish growth. As a consequence, 10 mg L(-1) alum was named as the optimum concentration that was applied in 1000 m(3) earthen fish ponds. Obtained results showed that Secchi disc values significantly increased from 10 to 24 cm after 14 days of alum application. Alum-treated ponds showed a reduction in total phytoplankton counts by 94 and 96% compared to the corresponding controls after 10 and 14 days, respectively. Abundance of blue-green algae in the treated ponds was decreased by 98% compared to the corresponding control after 14 days of alum application. Consequently, dissolved oxygen, pH, total phosphorus, orthophosphate, and chlorophyll "a" content declined significantly. Our study revealed that using 10 mg L(-1) of alum is an effective way to control cyanobacterial blooms in eutrophic waters, especially in fish ponds, without negative effect in water quality.