Planted drying beds in the African context: state of knowledge and prospects

Abstract

In low-income countries, the discharge of untreated fecal sludge directly into the environment is a common practice that poses a threat to both environmental and public health. Planted drying beds (PDBs) are a promising and low-cost option for treating fecal sludge. Therefore, in Africa, the use of PDBs for treating fecal sludge is increasingly valuable due to the technology's high efficiency, especially in tropical climates. This paper presents a literature review on the use of PDBs for treating fecal sludge in Africa, focusing on current research requirements and directions. This review shows that Echinochloa pyramidalis appears to be the most effective indigenous species used for this purpose, while also highlighting the lack of stability in the design and implementation models of PDBs. Standardizing and generalizing implementation methodologies for PDBs in Africa, researching new native and efficient species, and testing combinations of different species in the beds would all be beneficial.

Contribution of Newly Tested Species, Panicum maximum, for Faecal Sludge Treatment: A Comparative Study with Echinochloa pyramidalis and Typha domingensis

“…Although extensively applied in wastewater treatment, adapting reed beds for faecal sludge poses greater challenges due to its high variability and elevated concentrations of organic matter and nutrients, which can be 10 to 100 times higher than those found in wastewater (Niwagaba et al, 2014). Consequently, speci c research is imperative to customize the technology, especially for local contexts in developing countries, through the incorporation of indigenous plant species (Goussanou et al, 2023).…”

“…Past studies have concentrated on tailoring STRBs to tropical climates (Kengne et al, 2008;Kouawa et al, 2015;Gueye et al, 2016). Among the existing literature, Echinochloa pyramidalis stands out as a dependable species for faecal sludge treatment in tropical climates, given its treatment e ciency and economic advantages for resource and cost recovery (Goussanou et al, 2023). Research reveals that E. pyramidalis yields between 5 and 8 tons of fresh weight of marketable forage daily during both dry and rainy seasons, with prices ranging from USD 0.1-0.2 to USD 0.2-0.3 per kg of fresh weight, leading to daily earnings of USD 800-1600 and USD 500-1500 during the rainy and dry seasons, respectively.…”