Gauteng school benefits from a donation of solar powered water-recycling toilets
Submitted by: Tholakele Nene, Monday, March 16, 2015
In Olievenhoutbosch, one of Johannesburg’s oldest townships, lies Gauteng’s greenest school, Orefile Primary School. The school that boasts rooftop solar PV panels for its lighting and a grey water system is the first beneficiary of a South African manufactured solar powered water-recycling toilet that recycles toilet flush water using a solar powered pressure pump system. Two solar powered water-recycling toilet systems, created and manufactured by local green sanitation company, Smartsan, were donated to the school by ICT and solar PV distributor, Mustek.
A flush of dignity
It was during a time when cases of school children falling inside traditional pit latrine toilets was at a rise that Mustek and Smartsan decided to collaborate and invest in the development of a dignified toilet system that recycles toilet flush water using solar powered pressure pumps. The toilet system provides a dignified, cost effective and easy to maintain solution to one of the country’s biggest social problems of proper sanitation.
How do the toilets work?
Two solar powered water- recycling toilet systems were installed in the school yard for Orefile’s Grade R pupils. Each set of toilets consists of a small Smartsan tank sanitation system that sits underground and uses a combination of biological anaerobic processes and a nano filtration system to break down waste and remove contaminants, as well as a set of solar 120W PV panels that sit on top of the toilet structures to power a pressure pump system. Jurgen Graupe, CEO of Smartsan, describes the system in more detail:
The sanitation system requires 1,600 litres of water to get started and consists of four chambers that are designed to process the waste and eventually recycle safe grey water back into the system using solar powered pressure pumps connected to the cistern (See diagram and steps below).
- The first chamber (1) contains the raw sewage where the solids are broken down by anaerobic microbes that are added to the reactor. This watery mixture with fine solids passes through to the second chamber through a connection pipe.
- The second chamber (2) receives all the fine solids via a connection pipe (5). The fine solids are consumed by the microbes that were added to the reactor.
- The mixture from the second chamber flows into the third chamber (3) from the bottom and is the primary clarifier. The role of the clarifier is to ensure that any fine solids still present settle out back into chamber 2 and get dispersed.
- The mixture then flows into the fourth chamber (4), which is the secondary clarifier fitted with nano filters (6), a filter pump (7) and a large nano filter (8). Water first passes through the nano filters (6) where phosphates, nitrates and other dissolved contaminants are removed. Once in the chamber, the filtered water is recycled through a large nano filter (8) by the filter pump (7) and all the dissolved contaminants still present in the water are removed.
- A pressure pump (9) is connected to the toilet cistern and when a person flushes the toilet the pressure pump refills the cistern with safe grey water from chamber 4. The pressure pumps are powered by batteries that are charged by the solar panels. So when there is no sun, there is still enough energy to work the pumps and for people to use the toilet.
In cases where there is excess water, the system pushes the excess water into the ground which is agriculturally safe. “It’s an environmentally friendly system that uses bacteria and nano technology to break down the waste matter in an adapted treated tank buried in the ground and this is all powered by the sun”, says Michael Cassidy, Head of Renewable Energy at Mustek. A fitted gas filter cap (10) eliminates the odour emitted from the recycling process. This cap also prevents leakages and the spreading of water borne diseases such as Cholera.
This ground- breaking, environmentally friendly technology does not allow the use of harsh chemicals. According to Graupe, this will destroy the bacteria in the reactor and in turn affect the proper functioning of the system. Graupe says that regular maintenance is important for the toilets to function efficiently. This includes periodic inspections to ensure that the system is running smoothly, sludge management every one to two years depending on the amount of waste in the primary digester, and water replacement once a year of 600 litres.
Setting the pace for green schools around the country
The solar powered water- recycling toilets are an extension of Orefile’s mission to keep green and be sustainable. The school, which opened its doors two years ago, already uses rooftop solar panels to electrify the classrooms, and a water recycling system that channels water into a reservoir that is re-used to maintain the school garden and clean the school floors. During the construction of the school, cementless concrete and eco-friendly light weight steel frames were used which helped to minimise the impact of the construction phase of the school.
Talking about future prospects Cassidy says that he hopes more and more people and organisations invest in renewable energy and renewable technologies as this puts less pressure on natural resources.
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