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Chriwa Wasseraufbereitungstechnik GmbH - Wastewater treatment as a water scarcity remedy for Africa

Water is a very necessary part of every individual’s life. Due to pollution and harsh effects of industries the preserved water on earth is decreasing day by day. In most African countries, substantial quantities of wastewater from many commercial establishments like laundries, hotels and hospitals, freely mix with sewage. The larger the sewers networks, the more risky they are to operate, especially in developing countries which deploy only manual sewer cleaning processes.

In the west, sewage from toilets, kitchens, baths, wash basins, washing machines, etc are collected in each building, passed through sewerage (typically underground drainage lines) and taken to a corner of the city where a centralized ‘Sewage Treatment Plant’ (STP) treats it. This treated sewage is then discharged, to the sea or other water bodies. Most modern cities and towns were built many decades if not centuries back, and so such sewerage systems and STPs were also built long back.

The old wastewater management

In the old days, wastewater was not considered a reusable resource, and so the society was only interested in discharging sewage, either to the sea or other water bodies, or out in the open. STP technologies were so primitive that the STP areas used to stink, and so they built STPs in a God-forsaken corner of the city/ town where nobody lived anywhere nearby.

These STPs were huge in size, and consequently, had to be built to be adequate for the next 25 or more years, thus building over-capacity, which brings down the efficiency of the electrical systems, increasing the power consumption. Clearing sewer blockages and replacing old pipes becomes a huge mess in the centre of cities with such systems, and is costly as well.

They built sewer lines running across the city/town to the STP location. While the pipe sizes in the farthest locations were small, the pipe sizes became larger as they got nearer to the STP because the volume of sewage they carry increases. Close to the STP, the pipe sizes became very large. The typical cost of sewer lines was 6-8 times the cost of STP.

The current wastewater management

But things have changed since then. Clean water is becoming scarce in the continent. Communities have started looking at ways of re-using treated sewage. The continent is looking at an adoption of zero discharge concepts even in respect of sewage. Many countries have started legislating that industry shall not draw ground water, but have to treat sewage and re-use.

According to CEO of Keneco Environmental Company, Mr. Kimani Rebo, all water nowadays is waste water and there is therefore a need for thorough treatment of all water to ensure safety of the users. Rebo says that most ‘strange’ skin diseases, cholera, typhoid, dysentery and cancers affecting children are due to consumption of untreated water.

“There are a few factors that should be put into consideration when deciding on how to treat your wastewater. You need to get the water tested to establish the kinds of wastes present. This will ensure your water is treated efficiently. You should also consider the use your treated wastewater will be put into. Water meant for drinking or cooking goes through a more thorough treatment process than one meant for irrigation, for example. The size of the project also determines the method to be used. A wastewater treatment plant for a residential house is less complicated as compared to that serving an entire city,” explains Mr. Rebo.

Technological advancements

Just like the other industries, the wastewater treatment industry has also experienced technological advancements that look to improve the wastewater treatment process. Mr. Joost Paques of Paques one of the world’s leading companies in the field of development and construction of cost-effective purification systems for (waste)water and gases; based on innovative biotechnology, from the Netherlands mentions that, Africa has responded positively to technological advancements in the industry. They are very interested in the innovative new technologies, which are based on Mother Nature (bacteria).

A few new modern technologies are coming up which can treat sewage to high levels of purity, fit for re-use for not only gardening but even for toilet flush, car wash, industry including building construction, and even drinking. Moreover, the new plants have unique features, like for instance Idro Group from Italy manufactures plants that are very simple with “plug & play” mode. The plants can also run on solar energy which means they can be installed in areas which are not connected to the grid.

According to Franco Falcone the CEO of CIE, a specialist in the design, manufacture and installation of water and waste water plants specifically dedicated to metal finishing line from Italy, Zero Liquid Discharge technologies are of strong interest for African companies because they overcame problems of fresh water availability and sometimes lack of sewer network.

ZLD plant Angola
ZLD plant Angola

Cuss in Germany has recently introduced Membrane technology (MBR – Membrane Bio Reactor) to reach even the most strict effluent requirements and to re use the treated effluent (water saving in arid areas). In partnership with CHRIWA Water Technologies the effluent from the MBR system can be further treated with an RO system (Reverse Osmosis).

anaerobic WWTP softdrink
Anaerobic WWTP soft drink production

According to Mr. Joern Haase, Senior Project Engineer at Cuss, the response from the clients to the Cuss plants is very positive. “Due to the fact that Cuss does not sell ‘standard’ systems each project is especially designed for the clients needs. This guarantees that for each project the best technology and treatment method will be installed,” he adds.

Mr. Christian Eckert of Klaro, a specialist for small wastewater treatment plants up to 50 PE and bigger wastewater treatment systems of up to 1,500 PE from Germany explains that, in general, Africa is open to new technologies especially from Europe; however, they often opt for unreliable cheaper technologies. The conception for high-quality technologies, which conform to state of the art standards, but are a bit more expensive, has to be adopt for the industry to prosper even further.

Source: https://constructionreviewonline.com/2017/10/waste-water-treatment-3/