Nutrient Recovery from Domestic Effluent using an Indigenous Strain of Scenedesmus sp.

Abstract

The performance of Scenedesmus sp. in the phycoremediation of domestic secondary effluents and the high-quality production of the effluents for safe disposal are investigated in the current work. An indigenous strain of Scenedesmus sp. is obtained from a sludge thickness basin at a wastewater treatment plant. The characteristics of this microalgae are identified using a molecular analysis based on 18S ribosomal RNA sequences. The phycoremediation process is conducted in a photoreactor tank (5 L) with five different concentrations of Scenedesmus sp. (between 10 5 and 10 6 cells mL À1 ). The reactors are then placed outdoors (exposed to natural environmental conditions) for 8 days. The Scenedesmus sp. had the ability to remove 91.86%, 98.15%, and 93.11% of total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC), respectively, and reduce biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solid (TSS) by 86.5%, 69.9%, and 76%, respectively, at a concentration of 10 6 cells mL À1 . Moreover, the increase in the pH value during microalgae activity contributed to the increases in nutrients and characteristics percentage removal. The treated secondary effluents generated from the phycoremediation process after 8 days met the EQA 1974 (Regulation 2009) sewage sludge (standard A) in terms of TN and TP but is still not under the permissible limits for BOD, COD, and TSS. In conclusion, an indigenous Scenedesmus sp. is efficient in enhancing the quality of secondary wastewater to meet the standards required for reuse or safe disposal.

Ammonia Reflections on Unmodified Seaweed, Euchuema Sp. as Biosorbent of Wastewater

“…TSS concentration shows that the wastewater was incomparable to the effluent standard limit, which was more than 100 mg/L of Standard B. The result indicates wastewater discharge contains pollutants which can cause impact in human health and aquatic life [17].…”