Looking to the future, some aspects of urine diverting toilet technology are clearly promising. Separating urine from the solid waste reduces the time and cost of converting human solid and liquid waste to a safe, recyclable product. The Novaquatis urine source separation project at Eawag has developed a highly efficient wastewater treatment plan. It is based on using a slight variation on the same type of plumbing infrastructure that we use today for standard wastewater treatment systems. These systems do have some drawbacks in that they can be expensive, and do require ongoing maintenance of the grid which includes lift stations (counter measures to the ironclad plumbing axiom that “poop flows downhill”) and processing plants. In addition, they require all users in the area to use a specific type of urine diverting toilet and a dedicated plumbing system. Urine diverting toilets have a good reputation based on theory because most people who understand them think they are a good idea. That is not the same thing as thinking that they actually want to own one or learn how to use one. People are slow to change habits, especially toilet habits.
A much better approach to initiating urine diverting toilet technology is the flexibility found with the low-tech C-Head toilet system for several reasons. First, there is no proprietary plumbing required. Several options for waste disposal are available to the users including processing on the premises or transporting the waste for processing off site. For example, using the BEX kit (Bottom exit kit) accessory available for the C-Head, the urine can be directed into the existing wastewater system through the toilet flange. This method conserves on water usage significantly, using the sink and shower grey water to purge the line and carry the urine away. If a special plumbing grid is installed for just urine using the urine diverting toilet, a smaller diameter pipe can be used which would be cheaper and easier to install with minimal excavation and modern pipe laying systems. The solid waste could be managed in several ways. More on that in a minute.
At the wastewater treatment plant, the urine could be converted to a usable product, such as hydrogen gas, or electricity, or fertilizer, using new technologies. A dedicated, smaller diameter line for carrying concentrated urine to the processing plant may create issues with scaling. This can be overcome by using the household grey water to flush the line daily. In some cases such as a rural setting or an area where installing a grid is difficult or impossible, a system of holding tanks and pump out vehicles might be the best solution for transporting urine to a processing plant much like current septic tank service vehicles.
Another advantage of the C-Head system is that it can be integrated into an existing conventional sewer system for the sole and simple purpose of conserving water. This could be done on a volunteer basis or using tax incentives much like solar panels supplying energy to the electrical grid. This would allow an inexpensive test to determine proof of concept that would be neither intrusive nor expensive if it failed to find acceptance. If it proves to be successful and popular, then smaller communities could be established with engineered systems to make commercial use of the urine using the technologies mentioned above rather than creating a problem of how to dispose of it.
The solid waste could be managed in several other ways as well. It could be composted at the point of use using a simple recycling compost tower, if it doesn’t create a potential environmental hazard due to topography or some other valid issue. At-home composting could be monitored by code enforcement officials for effectiveness and compliance on a periodic spot check basis if the local government was in agreement with adopting the system. Considering the low cost of the system, an annual permit could be required, thus generating the income to cover the costs of monitoring. This could also be used to include adjacent homesteads outside the wastewater grid using the same annual inspections to insure protection of the environment for the community. The simplicity of the system makes it affordable to everyone and wavers for hardship could be implemented where needed. It places a minimal cost on the taxpayer should the community decide to subsidize the project.
The solid waste could also be set out with the recyclable waste in dedicated containers for collection by public works. Contrary to what many people assume, solid waste that has been separated from urine and covered in a carbon based medium like sawdust or peat moss, has no offensive smell. After being picked up, it would be taken to a processing plant where it could be commercially composted and processed into a commercial fertilizer like Milogranite. It can also be dehydrated easily and used as a fuel to create heat to dehydrate more of the waste. The ash can be used in a variety of applications, including mixing with concrete. All of this turns waste into a money making asset rather than a liability for the community.
I highly recommend reading the links to the articles regarding this topic. They will increase your understanding of how to get the “urine diverting, composting” toilet movement rolling. Please feel free to advance the conversation and make constructive comments and suggestions below.
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