Full Length Research Paper

Evaluation of Screening Level Technique (SLT) for pollutant removal in an engineered ecological system: a case study in Kenya

*Kennedy Omondi Otieno and Christian Thine Omuto

Department of Environmental and Biosystems Engineering, University of Nairobi

*Corresponding Author E-mail: otienook@yahoo.com

Received June 3, 2013;  Accepted July 3, 2013



This study was based on testing Screening Level Technique by way of evaluating biokinetic performance of an operating tropical Vegetated Submerged Bed system with specific focus to a pertinent 5 day Biochemical Oxygen Demand pollution indicator. The overall objective was to establish effectiveness of the Screening Level Technique as a design concept for a reliable Vegetated Submerged Bed system. The methodology applied was the estimation of the bulk removal rate at 200C. According to the concept of Screening Level Technique, the amount of pollutant removal in a Vegetated Submerged Bed system is quantitatively expressed in terms of Removal Efficacy which basically depends on the system’s hydraulic residence time and pollutant bulk removal rate. BODbulk removal rate at 200C was established as 0.48 day-1 and 0.53 day-1 from both Screening Level Technique and Kickuth model respectively. The validation of the Screening Level Technique was based on the test of statistical significance at 95% confidence level as quantified by probability value of the null hypothesis that the system BODbulk removal rate as estimated from the two concepts are equal. Statistically, the Screening Level Technique was found effective hence prospectively useful as a design concept for tropical Vegetated Submerged Bed systems 

Keywords: Biokinetic, bioremediation, removal efficacy, wastewater, pollutant, vegetated submerged bed.