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Wastewater Treatment in Africa
Challenges and possible solutions for wastewater treatment in Africa
By Dorcas Kang'ereha
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Image: WEC Projects Model R, Packaged Wastewater treatment plant
Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle with minimum environmental issues or that can be reused. The World Health Organization (WHO) defines sanitation as “the provision of facilities and services for the safe management of human excreta from the toilet to containment and storage and treatment on-site or conveyance, treatment and eventual safe end use or disposal.” Used water from toilets, showers, baths, kitchen sinks, laundries and industrial processes are examples of wastewater.
Global water demand is expected to increase significantly in the next few decades. Agriculture is responsible for 70% of total freshwater consumption worldwide (90% in the least developed countries), while energy and industry are responsible for 20%. The remaining 10% is used for drinking water, sanitation, hygiene, and other domestic purposes, this is according to Sustainability 2021 report.
The report further reveals that, wastewater is a crucial component of water resource management and neglecting wastewater issues generates significant negative impacts on the environment, the occurrence
of waterborne diseases due to the use of contaminated water sources, and the wellbeing of communities. Underestimating the impacts related to wastewater means seriously compromising the achievement of the Sustainable Development Goals (SDGs) of the 2030 Agenda which targets to improve water quality by reducing pollution, eliminating dumping, and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.” The achievement of this target is critical for achieving the entire 2030 Agenda and, in particular, for SDGs concerning health, education, cities, and industry.
A joint report by the African Development Bank, the United Nations Environment Programme, and GRID-Arendal reveals that, while significant efforts are being made across Africa to ensure better access and services, many places still have inadequate infrastructure for sanitation and wastewater management. This is happening at a time of greater need due to population growth, rapid urbanization, improving lifestyles, and industrial and agricultural expansion – all in a region that has low resilience to climate change.
Challenges facing wastewater treatment industry facilities
Poor waste management
According to Eng. Reuben Juma Onunga, Deputy Team Leader COWI A/S, there is a great challenge with the quality of effluent received at wastewater treatment systems. Poor drainage and poor solid waste management in towns and cities lead to an overload of wastewater management facilities. Poor drainage infrastructure means sewers that are designed to operate as separate systems with carrying capacity designed for wastewater get overloaded as they are temporarily turned into combined systems carrying wastewater and stormwater. More stormwaters also arrive at the wastewater treatment facility. On the other hand, poor solid waste management means excessive solids are washed into the sewerage infrastructure leading to blockages. Also, a solid waste handling burden is created
at the wastewater treatment plant. Excessive solids floating on ponds reduce the efficiency of waste stabilization ponds. Proper urban planning with an integrated approach to the management of drainage, solid waste and wastewater, and faecal sludge, should be adopted. Implementation of prepared master plans is also critical.
Lack of knowledge
“Most people don’t know that such technology exists, is one of the biggest challenges. They don’t believe that wastewater can be purified and reused. There is also the challenge that people mistake the technology for biodigesters which has not had the best results in solving waste water management issues,” says Emmanuel Kariuki Engineering Director Sewertech Kenya Ltd.
Ignorance
“The wastewater management sector in Kenya has lagged. Focus has been on the water supply sector. Water attracts more investments than wastewater. The neglect of investment in wastewater has led to pollution of the environment. It is now that investment in wastewater is picking up. Revenue from wastewater is factored in as a percentage of the water supply revenue and is usually recovered by adding it as a percentage to the water bills,” observed Eng. Onunga. “The recent investment in wastewater has focused on trunk mains. The laterals that connect the consumers to the trunk sewers had been ignored. It is now that the financiers are emphasizing last-mile connectivity to ensure the trunk mains and treatment infrastructure are not underutilized as before. In addition to attracting funding for wastewater infrastructure, it is important to ring-fence revenue from wastewater for reinvestment. Implementation of waste-toenergy approaches may also create additional commercial resources which make waste management profitable.” He adds.
Poor operation and maintenance
Rick from SBEF debates on Poor operation and maintenance. “No matter how perfect or complex the wastewater treatment is designed by the manufacturer, the system will eventually be handed over to the customers for operation. The people who take over the operation often have no way to run the system in a state of high efficiency.
For example, operators think that the more certain chemicals such as nutrient salts or coagulants are added, the better it is but to be honest, it is a waste of money or they think that the higher control of a certain parameter like dissolved oxygen, the better it is, and the same conclusion is waste a lot of power,” he reasons.
Compliance
“The other concern regarding the quality of waste arriving at wastewater management is the concentration of the influent. Poor monitoring of industrial waste discharge to the sewer system leads to the illegal discharge of industrial effluent into municipal wastewater treatment systems. Though the industries are mandated by law to pre-treat their wastewater or effluents to the standards that are fit for discharge to the sewer system or receiving water bodies, most of them don’t comply,” says concerned Eng. Onunga. “Measures such as the “polluter pay principle” have been considered to hold the polluting industries to account, but enforcement is weak. Most industries only comply when they hear the enforcement officers are visiting and it is not possible to tell what happens when the officers leave. The samples delivered by the industries to test laboratories for monitoring compliance are usually an improved version that does not reflect the daily performance of their treatment systems. The corruption of monitoring officers also contributes to false positive reporting in favour of the polluting industries, allowing them to go scot-free. The main reason why industries struggle with compliance is usually the high cost of industrial waste treatment both in capital and operation and maintenance costs. Continued surveys and sampling for industrial waste and guidance
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on economical treatment methods may be a solution. Industrialists should also be brought on board as important stakeholders in the wastewater management sector. Regulating institutions should deploy persons with integrity to the field,” he upholds.
Lack of competent resources and budget constraints
Karl Juncker, Director (Pr. Eng) at Wecprojects pinpoints on three major issues facing the
wastewater industry, but are not limited to:
a. Lack of competent resources (technical and administrative) in the WSA’s and municipalities to manage, maintain and operate the works.
b. Restrictive and slow procurement processes and an inefficient approach to resolving the challenge.
c. Budget constraints and the inability to effectively apply for and process budget through (an ineffective) supply chain.
“There is not enough budget for the project from client side. This issue is more likely to occur in small factories. Basically, we need to allocate more budget when we use more land and equipment but its the engineering cost that is not directly proportional to the amount of water it treats. The most basic wastewater system is not cheap and it is not easy for small factories to afford. Compare to the big factories, and according to the wastewater characteristics, maybe they can just use the basic system to deal with which is a small expense for them,” Adds Rick.
Poor planning
“Faecal sludge management is another area of concern. In the sanitation service chain, proper containment, emptying, transportation, treatment, and disposal of treatment byproducts is critical. Some waste finds itself in the environment due to poor containment infrastructures such as unlined pit latrines, unprofessional emptiers that discharge waste into the environment like in drains and on abandoned fields along the road to treatment sites, poor treatment due to inefficient faecal sludge treatment plants, and illegal disposal of treatment by-products. It is recommended to carry out socio-economic studies that provide adequate data to assist in the mapping and effective planning of the management of faecal sludge. A shit-flow diagram is a good tool for understanding the sanitation service chain. It provides the percentage of properly managed waste and poorly managed waste. This information is important for planning the reduction of open defecation and eventual phasing out of onsite sanitation methods such as unlined pit latrines, lined pit latrines, VIP toilets, and septic and conservancy tanks, as towns and cities transition their waste management approaches from onsite to water-borne. The private faecal sludge operators should also be well-trained and monitored. Separate wastewater treatment and faecal sludge treatment are also important to avoid shock loads on municipal treatment plants. Decentralized wastewater treatment systems (DEWATS) are also needed to capture waste where it is produced rather than focusing on centralized wastewater treatment. With DEWATS, wastewater treatment by-products may be used at the generation catchments, compared to by-products from centralized wastewater treatment systems which are usually in the outskirts of the towns and difficult to transport back for use in the catchments,” says Eng. Onunga.
Addressing the wastewater treatment challenges
Proper infrastructure and equipment
Management of wastewater is challenging. The requirement for the management of dirty water is higher than that of clean water. Special pumps are required to pump wastewater and sludge. Breakdown of electromechanical equipment is a common
occurrence. When pretreatment equipment fails, flooding results. Also, solids that escape the screens due to flooding find their way into the downstream wastewater treatment systems. These create a huge burden for cleanup, especially in waste stabilization ponds. The solids may also damage electromechanical equipment like pumps. When pumps fail, and there is no sufficient redundancy, flooding of the environment may occur. Pump and pretreatment equipment breakdown, in institutions without good emergency response may lead to long downtime during which the critical pretreatment processes are bypassed. The downstream treatment systems are in turn overloaded. The construction of holding ponds and raised treatment platforms and even cut-off drains may curb flooding. During design, proper provision for redundancy for equipment, a clear operation, and maintenance regime, and availability of spare parts and other resources are important considerations; this is according to Eng. Onunga.
Effective policies and strategies
On the other hand Eng. Junker believes in a serious re-look at the way the treatment industry is being run and change of policy and strategy in order to rectify. “The DWS is already looking into partnerships with private entities to assist – this is most likely the very best move they can do and I promote that it happens quickly and effectively,” he extols.
Education
Championing the wastewater industry, Eng. Kariuki is certain that emphasizing on wastewater education would really boost the industry and expedite the current challenges. “People need to be educated more and shown the results of wastewater treatment. They should also be educated on better ways to handle their wastewater,” he emphasized.
Consulting the experts
Finding a suitable consulting engineering company is one of the most important and critical step before implementing a wastewater treatment system project, this is according to Rick. “I think it is important to consult a suitable engineering company
before implementing a wastewater treatment system project. The reference condition is the firm has performed in the same industry of wastewater before. Due to characteristics of wastewater discharged from various industries are different, the design of systems will also be very different. If the industrial wastewater has high COD and requires biological treatment, I recommend using MBBR (Moving Bed Biofilm Reactor technology) because MBBR saves more than 60% of the area and compares to the activated sludge way, it is easier to maintenance and operate,” he commends.
“In our experience, our customers who use MBBR don`t need to hire professional operators. They just need to let the existing employees establish a simple education or SOP then can run MBBR well. This system is also suitable for small and medium-size factories but not all of industries are suitable for MBBR technology such as electroplating wastewater industry because you may need chemical coagulation to remove heavy metals in wastewater instead of using biological treatment technology. Finally, as for how to deal with your wastewater, let`s back to what I said in the beginning: find a professional wastewater engineering company to help you,” he highlights.
Proper legislation from the relevant authorities
“From the policy point of view, it is important to update all designs and practice manuals. This includes adapting them properly to the local needs and current trends in waste management. Various institutions that are charged with the responsibility of setting up environmental management standards should work together. In Kenya, the Water Resources Authority (WRA), National Environmental Management Authority (NEMA), and Ministry of Water, Sanitation, and Irrigation (MWS&I) all have standards regarding the quality of discharges to the environment. Some of the parameters have been found to be in conflict, making it difficult for designers to decide what requirements to adopt in design,” remarks Eng. Onunga. “A particular standard in one of the guidelines, dealing with the requirement for faecal coliform, seems to be very strict having been set at “nil”. This is more strict than similar applications in
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the region. Such unrealistic standards make wastewater management infrastructure unnecessarily expensive. The relevant professional institutions should open a discussion on these concerns and present possible solutions to the relevant regulatory bodies and the ministry concerned so that such inconsistencies are harmonized and accurately legislated,” he concludes.
Wastewater Treatment Consulting is a great help in achieving your wastewater treatment goals and solutions. These professionals have specialized knowledge in the field of wastewater treatment, and can help you make informed decisions that will help protect the environment. Major wastewater consulting firms have experts in wastewater treatment and can provide a wide range of services. They should be able to provide you with an analysis and design that fits your business needs.
Additionally, they should have the necessary infrastructure and resources to assist you. They should also offer expert witness engagements and specialized business services. This type of consulting also offers a variety of other environmental services, such as hazardous waste management and pollution prevention planning. These services are helpful to municipal and state government agencies, as well as businesses. Professional wastewater consultants can also help in obtaining the necessary permits required for any discharge of wastewater and optimize your wastewater treatment processes. Contact Wastewater Treatment Consulting experts today and make your operation safer, compliant and more efficient.
