Algal Production in Al-Samra Waste Stabilization Ponds PDF

Keywords

wastewater treatment plants, anaerobic, algae

Abstract

Al Samra Stabilization ponds is one of the largest waste water treatment plants in the world. This plant is formed of three parallel trains, each formed of two anaerobic, four facultative and four maturations ponds. It was designed to handle an average flow of 68000 M3/ day-1. The main disadvantage to the operational capabilities of the stabilization ponds is the heavy populations of algae which frequently occur in the effluents; however, algal populations that develop in the ponds play an essential role in their efficient operation. The production of algae within the ponds represents the reverse of the process which is normally considered to be that of waste stabilization. Algal production was studied both on a mass and on a count basis. The maximum algal count recorded was 3.0 x 10^10 cells/l in pond M-3 at 250 mm below the surface. Throughout the study period, Chlamydomonas was the most abundant algal genus in the ponds, Euglena appeared during November and December, while Chlorella appeared in low numbers during April and May. Hydrogen ion concentrations in the ponds ranged from 7.0 to 8.6, which is suitable for algal growth. Dissolved oxygen in the ponds was very low to zero due to high oxygen demand in the system. Old algae for yellow color, low chlorophyll content and low activity, appeared in the ponds due to increase in light intensity. Efficiency of treatment achieved in terms of BOD removal was as high as 97% for filtered saamples and 87% for nonfiltered samples.