HALF of Malawi has been declared a disaster zone after torrential rains left scores dead and tens of thousands homeless. Not only will the devastating effects of the flooding be felt for much longer as infrastructure has been laid to waste and crops destroyed, but also because only 10% of Malawi’s population has access to sanitation facilities.
This means that when flooding occurs in the country, sewage from latrines contaminates water sources and can lead to serious health risks. The flooding in 2012 for example led to a cholera outbreak since almost every household in the rural parts of the flooded areas only used pit latrines, and everything that was in them went into water sources.
With such a critical lack of sanitation facilities these occurrences are not a one-off in the country. In fact, apart from last year, Malawi encounters cholera outbreaks from September-October to April-May each year, which corresponds to the rainy season.
In periods without flooding, people living on and around the country’s lakes continue to be at high risk of cholera outbreaks since they use the lake as a source of drinking water and for their ablutions. Levels of faecal contamination are high, particularly in parts of the lake with stagnant water.
In fact, from available data, in only 15 of 50 African countries do more than 50% of their population have access to sanitation. A vast majority of “facilities” in rural and semi-urban areas use pit latrines which deteriorate the groundwater - consider that approximately 75% of Africans rely on groundwater for drinking - or are full leading to flowing wastewater.
It would seem that the best places to go to if you want to consistently find a flushing toilet would be in North Africa or on one of the African islands (except Madagascar).
But even this data doesn’t correctly depict the severity of the situation on the ground. For example, even though 75% of Moroccans have access to sanitation, roughly 60% of the country’s 546 million m3 of wastewater endds up in the Atlantic Ocean untreated. This is extremely harmful to aquatic life and a threat to the country’s economy considering fish is an important domestic and export commodity.
Sewage watered crops
In the water-scarce northern countries the wastewater also affects agricultural production since it is often used to water crops. In Marrakech alone, it is estimated that 2,000 hectares of agricultural land are watered with raw sewage. In Egypt, a study of the waterways and canals in the Nile Delta found concentrations of harmful materials which exceeded permissible limits yet, since the country is increasingly water poor, more and more farmers are now using pumps to siphon thousands of cubic metres of untreated sewage onto their farms to keep the crops growing.
This contamination is attributed to poor waste disposal practices which is responsible for a significant proportion of the world’s infectious disease burden. In Africa this is far worse since virtually no wastewater receives treatment before it is discharged. For the few countries that do have treatment plants, these plants face challenges such as high organic loads, uncontrolled waste input, power cuts, increasing wastewater flow rates, poor oversight and management, high energy costs and lack of re-investments.
In Madagascar for example, where only 14% of Malagasies have access to sanitation, the recent outbreaks and spread of the bubonic and pneumonic plague were attributed to poor waste management. The plagues are linked to the fleas carried by rodents whose numbers proliferated along Antananarivo’s canals since the capital has no formal waste disposal system. To make matters worse, since about 70% of toilets in the capital are pit latrines, it makes them a time-bomb for water borne-diseases.
Benefits of wastewater
Currently available treatment methods for wastewater are often chemically and operationally intensive, which might not be used in many places in Africa due to the lack of appropriate infrastructure. Yet, if wastewater is properly treated it can be an extremely valuable resource in an increasingly resource-scarce region.
As we saw in the cases of Egypt and Morocco, wastewater is already being used for irrigation in urban and peri-urban areas as well as in distant downstream rural areas of large cities in developing countries.
If the wastewater was treated, it’s reuse in agriculture would provide benefits to farmers in conserving fresh water resources, improving soil integrity, and improving economic efficiency. After all, even when treated, wastewater recycles organic matter and a larger diversity of nutrients than any commercial fertiliser can provide. Biosolids, sludge and excreta in particular, provide numerous micronutrients such as cobalt, copper, iron, manganese, molybdenum and zinc, which are essential for optimal plant growth.
Wastewater also however has the potential to provide valuable renewable energy. Biogas (a mixture of different gases produced by the breakdown of organic matter - such as human poop - in the absence of oxygen) can be used to help meet the deficiency in energy supply, in both Africa’s growing urban and rural areas.
Africa’s slums could turn their human waste problems into systems that provide them with cooking gas, as was seen in parts of the Kibera slum in Kenya. In Rwanda biogas plants were installed in all 14 of its prisons, one small part of the central African nation’s plan to use renewable energy rather than charcoal and firewood, that provides 85% of its energy needs.