Tag Archives: Our Toilet

Chris Buckley from UKZN in South Africa Visits Our CEPT site.

Following the FSM4 conference in Chennai, we hosted Chris Buckley from UKZN in South Africa at our CEPT site.

“Prof Buckley is a chemical engineer and has spent his career as a contract researcher in the field of urban and industrial water and effluent management at the University of Natal and currently the University of KwaZulu-Natal. The primary funding sources are the South African Water Research Commission, eThekwini Municipality, the Bill & Melinda Gates Foundation, Sasol and Umgeni Water. He has partnerships with many international research groups.” – taken Chris’ bio on UKZN’s Academic Staff page.

Chris leads a center of excellence in sanitation research at UKZN, and is one of our partners for our upcoming prototype deployment to Durban. Chris’s visit provided him the opportunity to see the Duke/RTI RT, its field site operations, and to help facilitate planning for the Durban installation.

Our Dedication to MHM.

This article written by WSSCC and distributed via the Guardian.com advocates for the linkage between sanitation and menstrual hygiene management (MHM).

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We whole-heartedly share this message, and have embodied this in our work in the lab as well as our field testing in India to develop our prototype systems. Our continued efforts are significant, and are informing design iterations where we are including MHM into our sanitation and waste treatment strategies. We are dedicating engineering R&D resources to MHM waste management and incineration strategies, social science research tools and approaches, as well as participating in extensive community engagement on how to best link MHM with innovative sanitation.

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Our prototype cabin provides a space, actually with extra space, for women and girls, all with the intent to ensure a clean, private, and safe toilet space that facilitates managing menstruation, provides water and space for washing, and encompasses safe strategies for menstrual product disposal. Our prototypes have an integrated pad disposal chute and provides a mechanism for, and the distribution of, pad products.

We have much to learn and refine, but our mission and purpose to address MHM as a central part of innovative sanitation technology development is clear.

How Our Toilet Handles Liquid Waste…

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A few weeks ago we published a post on how our toilet handles solid waste. In this post we’d like to follow up with how it handles liquid waste.

Liquid waste plays a vital role in our system. It isn’t there just to be treated. Like solid waste, liquid waste is integral to how our toilet functions as a complete, off-grid waste treatment system.

How it all works.

As I mentioned in the last post, when liquid and solid waste is introduced into our system both are separated and diverted into two separate channels.

All liquids flow through a slotted conveyer belt down into three separate settling tanks that, as they fill, spill into one another, removing sediment from the urine as it settles in each tank.

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Once the liquid waste has reached the third settling tank, it is then pumped into a series of three holding tanks. In these holding tanks the liquid waste is at first stored, then disinfected electrochemically, and then pumped into a third and final holding tank. This last holding tank is the reserve that is pumped into the upper flush tank to be used safely as flush water for the next person.

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It doesn’t have to stop there either. Depending on the system configuration that is built, once treated, the liquid waste can also be diverted into spigots for individual washing/hygiene purposes (though it shouldn’t be considered for drinking), flush water for urinals external to the unit, or even watering plants!

On the disinfection process.

The liquid waste processing module found in our system uses electrodes to convert the natural salts found in urine into oxidants such as chlorine. The electrochemically generated oxidants disinfect the liquid by destroying the pathogens that come from mixing with the solid waste. The electrochemical process also breaks down the organics in the liquid as demonstrated in this video by the change in color during processing, using a green food coloring dye in a simulated urine solution.

Waste nothing. Reuse Everything.

By design, RTI’s toilet is configured with the aim of harnessing the latent energy found in liquid (and solid) human waste. It not only treats the waste, taking it out of our water supply, but it also gives it new life to be used again. This is particularly useful in areas of the world where water shortages are an issue. Or impoverished areas, where people don’t have access to proper plumbing or sewer systems.

Yes, it’s a toilet and stand-alone waste treatment system. But it also has the capacity to be much more.

How Our Toilet Handles Solid Waste…

Many innovative toilets are being conceptualized, built, and field tested these days. And while many of them have waste treatment incorporated into their functionality, they often don’t have that waste treatment occur on-site. Human interaction is often needed to transfer the waste from the toilet to either an off-site treatment facility, a large processor like the Janicki Omniprocessor, a mass-scale biodigester or, in the worst situations, to a nearby water source.

In this regard, we aimed to get rid of the reliance on human interaction entirely. With our toilet, waste is processed completely onsite within the unit itself, without it ever coming in contact with human hands. Our system doesn’t require piped-in water, a sewer connection, or outside electricity: it’s a completely closed and off-grid. And with its smaller footprint, it can be placed in many different locations around the world where much larger waste treatment solutions could never fit. Here’s how it works.

Waste treatment starts with the immediate diversion of liquid and solid waste. When anyone uses our toilet and flushes, the waste is washed down onto a slotted conveyer belt that separates the liquids from the solids.

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Once that is complete, the conveyer belt engages and moves the solids into an actuator that mixes the solids into a slurry.

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That mixture then gets pressed through a much smaller tube where it is heated, dried, and turned into small pellets. The pellets are then pushed into a tumbler to be dried further before being dropped into a chamber that contains a corkscrew.

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This corkscrew then pushes the pellets uphill (drying them even further), before dropping them into an incinerator where they are burned to a fine ash. This ash can either be discarded safely, or used as fertilizer for feeding plants or crops.

corkscrew

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Additionally, the heat generated from drying and incinerating the solid waste, produces energy that is harvested and stored to power the system itself.

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Aside from clearing the ash out periodically (or occasional mechanical maintenance), our toilet system manages waste completely on its own. A closed system, providing total on-site treatment of human waste.

It is a clean, safe, healthier solution for anyone to use with dignity and confidence.