Insufficient wastewater treatment equipments in Africa

A research report of Sino-Africa wastewater treatment cooperation was released by Beijing Municipal Research Institute of Environmental Protection and Tongji University, to explore the possible wasterwater treatment technology transfer mechanism between China and African countries.

Equipment related to wastewater treatment is particularly insufficient in most parts of Africa, and the main demands for now are the following:

(1) Technology improvement of existing sewage plants

Dredging and maintenance of stabilization pond process system;

Energy-efficient equipment including slag removal grid with low energy consumption, solar water pump, etc. and

Synthetic liners used for stabilization pond.

(2) Construction and operation of secondary sewage treatment system

Stabilization pond is the mainstream of sewage treatment in Africa, but it is of little effect when applied to high-concentration industrial wastewater. It is feasible to add influent pit and anaerobic pond or UASB (which can be covered to produce biogas if required) before stabilization pond. Pretreatment is required by industries prior to wastewater discharge to sewage treatment system.

(3) System integration of sewage treatment process

Many African countries have good conditions for constructing wetland treatment system, such as abundant land resource and moderate climate. The problem is how to integrate such systems with existing systems (stabilization ponds primarily) to achieve optimization both in terms of energy-saving and system effectiveness.

(4) Equipment for energy recovery

On the basis of investigation results of sewage plants in Kenya, it is strongly recommended to recover energy from sewage and sludge treatment and reuse it within sewage plants (for example, automatic slag removal grids). In South Africa, methane gas from sewage treatment process is used as an alternative energy source. Equipment such as sludge anaerobic digester, biosolids incineration and electricity generation, heat exchanger and microbial fuel cells can be used in sewage treatment plant to recover energy from sewage.

(5) Distributed sewage treatment equipment

Most parts of Africa do not have the right conditions to build centralized sewage treatment systems as population is widely dispersed. Distributed treatment systems are indispensable, particularly packaged treatment technology for community sewage located in some industrial zone and oil field.

(6) Treatment equipment of sewage and sludge from oil field

Oil resources are relatively abundant in some regions of Africa and unavoidably result in oily wastes in sewage and sludge; if they are untreated for a long time, they can seriously impact local water body. Therefore, oil removal technologies and equipment are strongly recommended, especially in petroleum exporting countries like Libya.