Solar Enhanced Wastewater Treatment in Waste Stabilization Ponds

Abstract

One of the most popular off-site wastewater treatment plants used in the tropics is the waste stabilization pond (WSP). Although it has several advantages, its use in urban areas is limited because of its large land area requirement. Hence, this research is aimed at investigating if a solar-enhanced WSP (SEWSP) can increase treatment efficiency and consequently reduce the land area requirement. The SEWSPs of varying sizes, made of a metallic tank with inlet and outlet valves and a solar reflector, were constructed to increase the incident sunlight intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physio-chemical and biological characteristics for a period of 2 months. The parameters examined were total suspended solids, dissolved oxygen, 5-day biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), coliform, and Escherichia coli. The efficiencies of the SEWSPs, with respect to these parameters, fluctuated with temperature variation, with the shallowest SEWSP giving the highest treatment efficiency. The research revealed that the cost of treating wastewater using SEWSPs was approximately 2 times lower than the conventional WSP for the same treatment efficiencies. Water Environ. Res., 81, 540 (2009).

On the hydrodynamics and treatment efficiency of waste stabilisation ponds: From a literature review to a strategic evaluation framework

“…pond structural factors, such as the L/W and baffling, Agunwamba and his co-workers (Agunwamba, 2008;Agunwamba et al, 2009;Utsev and Agunwamba, 2012a;Utsev et al, 2013) investigated an alternative potential of optimising WSP performance from the viewpoint of solar-mediated disinfection mechanism, and proposed the concept of solar enhanced WSPs (SEWSPs). A SEWSP is an upgraded conventional WSP fitted with solar reflectors to concentrate more incident sunlight radiation.…”

“…A SEWSP is an upgraded conventional WSP fitted with solar reflectors to concentrate more incident sunlight radiation. A SEWSP is usually characterised by higher pond water temperature (Agunwamba et al, 2009), increased removal efficiency of BOD, COD, total suspended solids, E.coli and total coliform compared with a conventional WSP (Agunwamba et al, 2009;Utsev and Agunwamba, 2012a, b). the solar reflector at the outlet of the pond and/or ponds being constructed with hydraulic jumps (steps) (Agunwamba et al, 2013;Ogarekpe, 2017).…”

Effects of Aspect Ratio on Solar Enhanced Waste Stabilization Ponds

“…A solar enhanced waste stabilization pond is a new technology that evolved as a result of the incorporation of solar reflectors in the conventional waste stabilization pond for the purpose of increasing the efficiency and reducing the land area requirement of waste stabilization ponds (Agunwamba et al, 2009). For a rectangular waste stabilization pond (WSP), the aspect ratio denotes the ratio of length to width of the WSP, usually a minimum of 2:1 is recommended (Marais, 1966).…”

“…In natural treatment systems such as WSP, the pathogens are progressively removed along the pond series with the highest removal efficiency taking place in the maturation ponds (Mara and Pearson, 1998). Although solar inactivation of bacteria in wastewater is well established (Sinton et al, 2002;Benchokroun et al, 2003;Davies-Colley et al, 2005), the efficiency and economics of integration of solar reflectors in ponds has also been investigated (Agunwamba et al, 2009). Hence, the aim of this study was to determine the optimum length to width ratio for the design of solar enhanced WSPs for more efficient wastewater treatment.…”

The Effect of Hydraulic Jump on the Performance of Waste Stabilization Ponds

“…WSPs are limited in application by their large area requirement [6]. In the past, researches have been conducted to improve pond efficiency, thereby maximizing land use by solar enhanced wastewater treatment in waste stabilization ponds [7], using optimization techniques [8], using recirculation stabilization ponds in series [9], step feeding [9], incorporating an attached growth system [10] and more accurate estimation of pond design parameters [11][12][13][14][15][16][17]. In addition, higher pond depths have been investigated for reduction of the pond surface area [18][19][20][21].…”