The yellow plumber
The provision of plumbing products and services that can save water, use less energy and ultimately look out for the environment is encapsulated in the role of the ‘green’ plumber. In light of this, it seems another type of plumber is on the verge of brightening the industry – the ‘yellow’ plumber.
A rapid depletion in available phosphorus reserves (a key ingredient in the recipe for agricultural prosperity) has led researchers across the globe to begin developing urine diverting toilets. As human urine is a readily available source of phosphorus, this new toilet product aims to capture urine and reuse it in agricultural fertilisers – hence the name, ‘yellow’ plumber.
Urine diverting toilets are one step closer to becoming a common feature in buildings of the future, as they are already being trialled in Sweden, Germany, the Netherlands, United States and China. Although the first-generation toilets are still progressing through the feasibility stage, it is essential for plumbers to have a basic knowledge of how they work and what the installation process will involve, especially as Australia is set to follow suit in a home-grown initiative.
Research pioneers at the University of Technology Sydney (UTS) have recently started a research action project to explore the use of innovative urine diverting toilets in an institutional setting. Led by the university’s Institute of Sustainable Futures (ISF), a challenge grant involving 10 collaborators will aim to enable the safe nutrient capture and reuse of urine from the first-generation toilets installed on campus during a trial period.
UTS associate professor of sustainability Cynthia Mitchell, says urine diverting toilets are the most feasible way to extract urine from sewerage.
“One option is to collect the sludge from the sewerage treatment and incinerate that to create a by-product which is rich in phosphorus. You can also do a form of chemical precipitation at a sewerage treatment plant but that could result in a cocktail of heavy metals,” she says.
“If you capture the urine at the beginning of the waste process, you don’t have all of those mixing problems. It’s like adding milk to a cup of tea; you can get it out, but it’s very difficult.”
She says that urine diverting toilets involve subtle tweaks to the standard toilet design, resulting in what you might describe as a ‘funny dunny’.
“There are a whole lot of trade-offs that you have to make during the design process and different companies will make different trade-offs, resulting in different strengths and weaknesses of the finished product,” she says.
“Basically, it is a standard toilet that has two holes instead of one. There are slightly different variations in the designs, but most of the technologies have either one flush for both bowls or separate flushes.
“For example, the Dubbletten design from Sweden tries to ensure a very good separation between urine and faeces as well as reduce the water that is used in toilets generally. Their design has quite a high bridge between the bowls and a very low volume flush for the urine.”
The first-generation design of urine diverting toilets at UTS has come with its fair share of difficulties, particularly as the trial is a retro-fit installation in an existing toilet block.
“Urine is quite concentrated in terms of salt and if it sits for any period of time you get a precipitate forming, which makes it complicated to have a separate S-bend. There are also significant behavioural changes that are not being dealt with yet,” Cynthia says.
“Even so, we’re excited to take on the challenge as there has been no development of urine diverting toilets in Australia so far. It’s a significant business opportunity to leap into and people are always happier to hear about local results.”
Given this, the UTS research team will be looking at a number of technological questions during the campus trial.
“We’re looking at issues such as how the toilets work and the storage of urine. We’re also going right through to the reuse of urine and its impact on agriculture, so there are all kinds of questions to be answered,” she says.
“When you start to store urine onsite, you could trigger some regulatory issues about urine and the waste, what it means to store it, how you’re going to look after OH&S and publish health issues. There are also economic regulations. In time, phosphorus derived from human urine is going to be a marketable commodity – but who owns the phosphorus and what right do you have to take money out of that?”
Cynthia believes that plumbers would benefit from following the progression of urine diverting toilets, both in Australia and overseas.
“It’s a significant development to keep track of because the current issues revolve around the design of the urine diverting toilets and ultimately the need for different regulations for the pipe work. By changing these regulations, it has implications for plumbers’ training,” she says.
“Plumbers will need to know about the different approaches to installing these new toilets – it’s about understanding that urine is different from other sewerage so you need to take a different approach. Working out what the principals are and getting them into industry training is going to be critical.”
After speaking to various training providers, Cynthia believes there will be a future increase in ‘yellow’ plumbers as well as ‘green’ plumbers, which ultimately leads to more job opportunities and the creation of specialist skills.
“The results from our trial and the continued support of the industry will help to shift people’s perceptions about urine diverting toilets. My message to the plumbing industry is simple: look out for ‘yellow’ plumber’s training.”
Dubbletten urine diverting toilet
Swedish company BB Innovation & Co. AB is leading the way in phosphorus research with a new generation of low-flushing urine diverting toilets. The company’s Dubbletten toilet is based on the principle of resource recovery and the need to address the water, sewerage and nutrient management cycle for urbanised environments.
BB Innovation managing director Bobby Mrozowski says during the last 18 years, he has aimed to achieve ecological balance between urban and rural areas.
“The issue of urine separation is more than my job, it’s really my passion and commitment,” he says.
“The human body is the best water and sewerage treatment plant in the world and the waste sorting is accepted as an essential part of resource recovery. In the process of wastewater purification, significant benefits can be accomplished by sorting the waste flows at the source, within the building drain pipes.”
The unique patented design of the Dubbletten toilet is based on two separated bowls – one for faeces and another for urine. They are separated by a high bridge which prevents contaminated water overflowing into the urine bowl when the toilet is flushed. A separate pipe is also available to collect the urine, which can then be reused as a fertilizer in agricultural activities.
Bobby says the Dubbletten toilet can be installed into new or existing buildings and approximately 80% of water is saved in comparison to a standard toilet.
“Water and sanitation are some of the most important issues regarding sustainable urban development, which in my opinion is impossible to achieve without sustainable water sanitation like Dubbletten.”