Category Archives: Liquids

Prototype Update, 6 Jan 2017

Liquid System Update:

North Carolina, United States

Throughout the month of December, the liquid team focused on testing out the new baffle tank design. The new baffle tank is a great success with data showing it improves effluent qualities surrounding social acceptability. We have also gained valuable information on potential system parameters that may be adjusted to further enhance the electrochemical process and effluent qualities. During the month of January the liquid team will focus on exploring and optimizing these parameters

The graphs presented below highlight the effluent differences between the older baffle design (alpha) and the new one (beta 2.0). From the top graph, we can see it takes nearly twice as much material (on a user-day equivalent basis) for the conductivity (which reflects the accumulation of salts in our recycled process liquid) to reach its plateau in the new system. In the bottom graph, the total suspended solids (TSS), a measurement related to the turbidity, or cloudiness of the effluent, are consistently lower with the new baffle design. Both of these improvements are attributable to the superior design of the new baffle system.

Prototype Update, 1 December 2016

Liquid System Update

North Carolina, United States

A new fully automated Beta 2.0 system was recently installed at the RTI testing laboratory in the US.

This biggest change for the liquid system was a redesign of the baffle tank. The new design helps to direct flow away from the outlet. This new system has been up and running for 65 days and has processed over 10 kg of feces and 100 L of urine.

We will continue to test in this new system to develop and refine processes that allow us to not only disinfect the effluent, but meet social expectations and discharge standards.

The video below shows a flush with green food coloring being followed by a flush with water in the new tank.

Liquid Waste Processing Update

It’s been a bit since we gave an update on the status of our Liquid Waste Processing Unit so we thought we would take some time and put up a quick post about the unit and the recent changes we are evaluating with it.

Electrochemical Treatment of Urine and Feces

First and foremost we’ve started evaluating the use and efficacy of a different type of electrochemical cell in the liquid disinfection system itself. This electrochemical cell is adapted from a commercially available consumer product, which is good for several reasons, chief amongst them: potential lower cost and energy requirements.

During this evaluation, we’ve found the initial test results to be very encouraging! (see below)

The photo on the left shows a tank of urine and feces prior to electrochemical treatment. The photo on the right shows the same after treatment.

Urine and Feces disinfection test results

Plot of E. coli concentration and energy consumption over the course of a treatment test.

The 90 L tank test

Photograph of 90 L processing tank filled with 60 L of fecal contaminated urine.
The 90 L processing tank filled with 60 L of fecal contaminated urine.

We are also in the process of testing a larger 90 L processing tank.

During field trials of the RTI toilet, liquid waste processing will be carried out once a day. This process needs approximately 90 L of waste to complete.

Due to the larger size of this processing tank, tests are currently being carried out to understand how this level of  scaled up processing would impact the overall function our toilet.

Those results will be posted here as soon as they are available!

Disinfection of Fecal-Contaminated Urine (update)

Plated Specimens from Before and After Processing

Plated specimens from before and after electrochemical treatment of fecal-contaminated urine (human)

The first series of tests used 16 liters of human urine mixed with 0.5 %wt of human feces. This represents a significant milestone in demonstrating the liquid disinfection capabilities of the system using actual human-derived specimens. Future tests will focus on evaluating energy consumed during disinfection and further process optimization.

Liquid Processing Team testing with human urine contaminated with human feces

The RTI Liquid Processing Team prepares the system for disinfection tests with human urine and feces.

Collection tank showing fecal-contaminated urine before processing

Collection tanks holding the fecal-contaminated urine before processing.

The baffled collection tanks allow solids to settle and dissolve prior to entering the process module, eliminating the need for prefiltering the liquid before entering the electrochemical cell. Based on preliminary observations, the 0.5% fecal load represents a worst case for fecal contamination in the urine. Future experiments will evaluate nominal and peak-loading scenarios.

The Liquid Waste Processing Module

TRL5b Liquid Processing Module

The latest version of the Liquid Disinfection Module is more compact and semi-automated. Solenoid valves and level detection switches control the flow of liquid from collection to process to holding tanks.

The liquid waste processing module uses electrodes cheap jerseys to ?irketleri convert the natural salts found in up urine into oxidants such as chlorine.  The electrochemically generated oxidants disinfect Jerseys the liquid by destroying the pathogens that come from mixing and with wholesale nfl jerseys the solid The waste.  The electrochemical process also Emptying breaks down the organics in the liquid as demonstrated cheap nfl jerseys in this video by the change in Helical color during processing, using a green wholesale nba jerseys food coloring 60 dye Home in a simulated urine solution.

Dr. Ethan Klem demonstrates the electrochemical disinfection module designed for manual control.