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W EEKLY EDITION JULY 12, 2017 Dispatch #3 from South Africa …continued Research Reveals New Ways of Extracting Value from Human Waste DEWATS uses a decentralized, modular approach to sanitation. The philosophy behind it incorporates flexible sanitation solutions with many possible applications. They are modular, adaptable systems that combine low - technology treatment components that can be locally eng ineered, supplied, built, operated, and maintained. DEWATS can be designed to manage and treat domestic wastewater, pit latrine sludge, and organic industrial and institutional wastewater. It is a comparatively compact site solution, and the ideas behind i t may eventually prove to be adaptable for portable sanitation operators and small communities. This image (foreground) shows what the DEWATS system looks like from above ground. Below ground, DEWATS includes the following components: • Settler - The settle r is the primary sedimentation chamber, where solid particles are separated by gravity. • Anaerobic Baffle Reactor - The Anaerobic Baffle Reactor is an improved septi c tank with baffles to separate the tank into 4 or 7 chambers. The baffles force the wastewa ter to flow up and down through the chambers, increasing contact with the anaerobic sludge, which digests a large portion of the organic matter. • Anaerobic Filter - The Anae robic Filter consists of a bed of coarse stones , which retain the remaining solid pa rticles and further degrades organic matter. • Vertical Planted Gravel Filter - The Vertical Planted Gravel Filter provides secondary wastewater treatment , which takes place in the root zone of wetland plants. The pre - treated wastewater is released onto the surface of the gravel filter several times each day, where it flows vertically through the planted sand filter. The aerobic conditions further degrade or ganics and provides some nutrient and pathogen removal. • Horizontal Planted Gravel Filter - The Horizontal Planted Gravel Filter provides additional treatment as the wastewater flows horizontally through the planted gravel bed. Organics are further degraded , and more nutrients and pathogens are removed. This photo should give you a better idea of how the system is laid out underground. CONTINUED ON PAGE 4 P AGE 3