This research study investigates "How ecological sanitation can become a feasible answer to improve sustainable waste management in Norway?". Through a holistic systemic analysis, the entire sanitation system in Norway has been examined thoroughly. Even indirectly related systems have been included in the study: agriculture, economy, legislation, politics, culture, habits, behavior, consumption, pollution, water treatment, waste treatment, and the environment have all been studied to investigate where improvement is possible and whether a more ecological sanitation alternative can provide an answer.

A shortened version of this study is published here. Please click on the following link if you want to read the whole research article:

I quickly realized that Norway could also benefit from ecological sanitation as unusual little snowfall and precipitation during the summer of 2022 caused low water levels in the Nordmarka reservoirs despite all the efforts asked from citizens to save water by Oslo municipality (Oslo Municipality, 2022).

Replacing flush toilets with an ecologic sanitation alternative would enable Norwegians to save on their water bill, and all the downstream benefits including lowering their water consumption and not creating polluted water that must be treated.

But could a whole city switch to ecological sanitation toilets?

Toilets have undergone many changes since their appearance five thousand years ago. But how will sanitation evolve from the current flush toilet system? What toilet system(s) can replace the commonly used flush toilet systems in developed countries such as Norway to support a more environmentally friendly sanitation system?

Dry toilets were mostly used in countries that had water scarcity, no running water, no sewer system or suffered from diseases, today this is still true.

The flush toilet was invented in 1596 before the emergence of the modern dry toilet in 1873 and it grew in popularity throughout the mid-18th and 19th centuries. Despite cutting maintenance costs and eliminating odors associated with sewage systems, dry toilets didn’t become widely used because flush toilets were increasing in popularity and were convenient to use. This proves the point that technical aspects and practices are interdependent and are the key components that contribute to user acceptance of a toilet system (Kaur Bhatti, 2021).

Only the dry toilets from Henry Moule and China’s Han Dynasty were successful at preventing pollution of the environment and spreading of diseases because the waste was immediately recycled by pigs or treated with covering materials.

The noxious odors of sewage have recorded associations with disease as early as 100 BCE (de los Reyes, 2021), this goes to show that many cultures always had a disgust and aversion towards their own waste.

Yet in eighteenth century Japan, Japanese citizens did not view human waste as unwanted waste, but rather as something of value. They were even arguing about who had the rights to collect it, keep it, and use it. The answer on why they had a different view than ours lies in the soil.

Compared to many European and North American countries, blessed with an abundance of forests and fertile grounds, Japan had much less land that was suitable for agriculture. Large parts of Japan had soils that were sandy and low on nutrients. Without continuous fertilizing with human waste, they didn’t yield rich harvests (Zeldovich, 2019). Agriculture and human waste are closely related and whether or not a nation has fertile soils dictates their culture towards human waste.

Ecological sanitation is a sustainable model that promotes the treatment of human excreta as a resource rather than waste, as well as using less freshwater for the sole purpose of disposing of human waste (Kaur Bhatti, 2021).

A flush toilet is a toilet that disposes of human waste (urine and feces) by using the force of a water vortex to flush it through a sewage system to a communal wastewater facility or septic tank, thus maintaining a separation between humans and their waste. Sewage systems typically undergo wastewater treatment; the removal of pollutants from the wastewater to what is considered acceptable to release the effluent back into the environment.

Flush toilets waste anywhere from 6 to 20 liters of water per flush which makes it responsible for up to 40% of water consumption in Norwegian municipalities (Kaur Bhatti, 2021). Flush toilets are the largest single user of water inside the home, turning potable water into wastewater that is expensive and resource-intensive to purify.

Dry toilets are the interface of sanitation systems that do not use flush water to convey human excreta or block odors. The fundamental principle of dry toilets is the absence of water in the use, handling, and transport of human waste (Kaur Bhatti, 2021).

Human feces naturally break down into pathogen-free compost in the presence of oxygen and covering materials such as sawdust to absorb the liquid. Many different types of dry toilets exist, what differentiates them is how human waste is managed and treated. Dry toilets is an ecological sanitation system as it closes the loop between sanitation and agriculture.

Vacuum toilet systems are a type of  flush toilets that rely on vacuum suction for the removal of feces and urine resulting in a minimal requirement of water 0.5 to 1.5 liters/flush compared to 6 to 20 liters/flush with traditional flush toilets (Kaur Bhatti, 2021).

The reduced water consumption helps saving costs, allows for onsite waste treatment and it produces a viscous sludge that contains a high nutrient concentration, ideal for fertilizer and/or soil amendment in agriculture (Kaur Bhatti, 2021).

The good functioning of a vacuum toilet relies on vacuum suction, electricity and a well designed plumbing blueprint. If there's an electricity outage the toilet can't be used. (Kaur Bhatti, 2021).Vacuum toilets are more vulnerable compared to flush toilets in regards to clogging due to poor flushing behavior, flushing foreign objects and coarse or bulky materials (Kaur Bhatti, 2021). Municipal services remove wastewater from the holding tank and transport it to farmers or a wastewater treatment facility. Vacuum toilets have an ordinary appearance and there is less discomfort with bad odors compared to water flush toilets. Vacuum toilets do not produce bioaerosols or visible splashes which makes it a sanitary alternative especially in light of the COVID pandemic (Kaur Bhatti, 2021).

The system is difficult to regulate in communities and public buildings where users hold no responsibility for compliance and there is little liability for poor flushing behavior restricting the system to operate at its full potential (Kaur Bhatti, 2021).

The noise is described as very loud or unpleasant by users. Vacuum toilet users avoid flushing during the night hours to prevent disturbances to others sleeping (Kaur Bhatti, 2021).

Vacuum toilet systems are complex and consist of a lot of moving parts increasing the likelihood of it being more high maintenance.

An incinerating toilet evaporates the moisture that is left in our waste and incinerates the waste to a fine gray ash that is safe and sterile to mix with the soil in your vegetable garden. The moisture, odors and fumes are filtered and extracted through the air outlet.

A family of four produces 1 teacup ash/week (Margel, 2023). This is almost negligible compared to 450 liters of water flushed away over the course of a week for a family of four with a flush toilet (Margel, 2023).
As the bowl liner collects the feces the bowl stays clean and reduces the need to clean the bowl regularly. The toilet does demand a change of habit because for every visit you need to place a bowl liner. However children that have grown up using an incinerating toilet understand the correct behavior pattern right away because it is an easy habit to get used to (Margel, 2023).
The toilet is a little bit higher compared to flush toilets to accommodate the heating elements at the bottom that burn the waste. However a stool is provided for children to reach the toilet. The simpler and more user friendly a toilet system is, the more adaptable it is to broad use (Margel, 2023).

The toilet doesn’t make any obtrusive sounds, it makes less noise compared to a dishwasher. The system is closed when incinerating waste, the toilet is insulated and a child can touch the outside of the toilet during an incineration cycle and not be burned (Margel, 2023).

The backdrop of the incinerating toilet is that it requires 2kWh of electricity per incineration cycle or it needs to be fueled with propane gas. The Cinderella toilet is not cheap and would be a significant purchase for anyone, prices start at 4,351€. 

The nutritional value of the ashes by themselves is questionable and needs more testing. However, the mixture of ash and soil promotes plant growth similar to the recurrence of plant growth after a forest fire. That’s why many people use it as fertilizer in their gardens.

The idea is simple: a diverting compost toilet collects urine and feces separately at the source without using precious potable water. Human waste is treated just as any other organic matter in a not dissimilar way to how kitchen waste is composted. Instead of causing nutrient pollution in local water bodies, our nutrients can be composted to safely and effectively grow plants and support local food production.

Feces and urine are separated at the source using special collectors to allow separate management. It facilitates storage, management, treatment and recycling of the separated excreta and closes the loop by returning nutrients and organic matter back to the environment for better soil quality and food production (Evgenieva Kelova, 2022).

Urine is particularly rich in phosphorus, a vital component of manufactured fertilizer that is currently mined from phosphate rock, a finite resource, so diverting urine is a good idea (Saner, 2019). 

Composting is the best process to preserve the nutrients in the waste and break it down to plant usable form (Evgenieva Kelova, 2022). However, a diverting compost toilet is not a total waste handling solution. After handling is needed to break down the feces to plant usable form and get rid of medication residue and pathogens.

If managed properly, feces which contain most of the pathogens can be safely used as a fertilizer after storage either at ambient temperatures (20°C) for two years or composting at high-temperatures (50-70°C) for six months (Kaczala, 2006). The pathogen die-off takes place in consequence of UV radiation, dryness and competition with other soil organisms (Kaczala, 2006). 

Backyard composting is a widely known and accepted practice also for other organic household wastes. The high temperatures (50-70°C) reached during composting have been proven to eliminate pathogens and sanitize the material but successful composting is not easy to achieve in self-contained toilets or small-scale domestic composters.

Major costs and strict regulations associated with connecting to sewage can be avoided by using a diverting compost toilet while still enjoying the same comfort and convenience as with a flush toilet.

Some limiting factors of diverting compost toilets that withholds people from being able to enjoy the advantages of this dry toilet are: 

The lack of time and physical space (garden) to let waste compost for 1-2years.

Required effort and knowledge to handle and manage the compost to get the desired end-product.

Klaro system in its essence is a scaled down wastewater treatment plant for homes that have no access to a main sewer or where a conventional septic tank is not suitable.

The Klaro system runs 4 clarification cycles/day. 1 clarification cycle takes 6 hours and cleans the water 98%. The treatment capacity of one Klaro tank is 7,5 m³/day. The Klaro wastewater treatment system consumes just over 10€/year on electricity. Sludge is removed by an annual municipal sludge collection service and brought to a municipal wastewater treatment plant for further treatment.

The lack of the Klaro system to close the loop between sanitation and agriculture makes it unqualified to be considered as an ecological wastewater treatment system.

A decentralized wastewater treatment system such as the Klaro system is however effective at reducing the load on existing municipal wastewater facilities that are already running at maximum capacity allowing communities to develop and deal with climate change, extreme weather events and rising water tables with more ease.

Through giga mapping and diverging the currently used flush toilet system, sewer system and wastewater treatment system in Norway, I identified several areas of opportunity where ecological sanitation could potentially offer a more sustainable solution. In the map above areas of opportunity are illustrated within the current flush toilet system in Norway and below areas of opportunity in the current monoculture system are illustrated.

Parts of today’s water and sanitation systems in Norway are not adapted to extreme weather patterns due to climate change and a growing population. Increased precipitation, floods and rising sea levels will in the future be a challenge in many municipalities (United Nations, 2023), especially for wastewater treatment plants near shorelines (Solberg, 2023). In addition, precipitation and the risk of flooding and landslides due to climate change will increase the risk of damage to pipelines in the future.

Denmark has a lower water consumption per capita compared to Norway, because there is a difference in how the monthly water bill is calculated. In Denmark it is calculated based on your personal consumption. In Norway a utility bill is paid which means that the cost for water consumption and wastewater treatment is a shared cost which accounts for the municipality's average water consumption (Margel, 2023). Norwegian’s personal water consumption doesn’t reflect directly in their utility bill thus citizens have no notion of whether they consume water economically or not. This proves that the economy and the environment are intertwined.

Some of the main barriers to dry toilet systems and nutrient recovery are:

- Opposing cultural and societal perceptions

- Unfamiliarity with the dry toilet sanitation system

- Recycling human waste is deemed to be difficult or inconvenient

- Being confronted with your own waste

- Perceived association between bad smells and diseases

- Excreta can contain harmful pathogens, therefore humans have a survival instinct that creates a natural repulsion towards feces.

- Old habits become barriers to comply with other toilet systems

- Dry toilets are mainly used in rural areas and underdeveloped countries

Nutrient recovery from human excreta is an acceptable model to implement as long as it is scientifically proven as safe for human and environmental health concerning hazards, such as biological pathogens (Kaur Bhatti, 2021)

In order to change people's behavior towards dry toilets, the most important is to ensure that the toilet system is scientifically proven as safe for human and environmental health concerning hazards, such as biological pathogens.

Psychology, evolutionary adaptations, or religious norms and practices are important and

relevant approaches to understand peoples’ inherent and learned feelings towards human excreta and practices associated with the handling of human excreta (Kaur Bhatti, 2021).

Another effective way to get compliance is by making the culture more accepting toward the use of dry toilets and nutrient recovery. By slowly educating and exposing people to positive individual learning experiences. This will allow societal norms and perceptions to slowly shift.

The farmer interferes in the soil regeneration loop by removing organic matter that supplies the topsoil. As the harvest rate of the farmer is higher compared to the rate at which the soil can regenerate, the fertility of the soil enters a negative feedback loop. Which is a loop that counters a system that keeps trying to bring it into equilibrium (it is stopping the growth) (Meadows , 2019). As a result the depleted soil needs artificial fertilizers to restore the nutrients in the soil.

When this loop is sustained long enough it will reach a threshold at which point it becomes an erosion loop. Which means that we have taken down the system so far that when the more we attack the system, now instead of coming back and the soil regenerating itself it gets weaker and weaker. It is a loop that is taking the system down (Meadows , 2019).

This can only be prevented by reintroducing organic matter on the field not with the purpose of harvesting it but letting it decay to resupply the topsoil with mature organic matter or the farmer can lower his rate of harvesting which is an unrealistic solution considering the slow pace of soil regeneration.

The hierarchy of intervention by Donella Meadows was used to structure the solutions according to their level of influence on the system.

To give ecological sanitation any chance, awareness needs to be created about the “One Health” approach. This will make people aware about how human health is dependent on healthy soil and clean water sources. We need to stop seeing ourselves as disconnected and in control of nature but rather being part of nature. This helps with recognizing that human waste shouldn’t be perceived as waste but as a resource.

A change in mindset is needed to change people's relationship with water. Many people are unaware how water use affects the environment (Borgan, 2019). Norwegians are more concerned with whether our tap water is safe to drink, than if we waste it (Borgan, 2019) this is a culture that needs changing.

To create sustainable long-term solutions we need to revisit what value and purpose water has in our lives and think about how we can preserve that value in the future by redesigning our relation to water, how we use it, what we use it for and how we take care of it. As issues linked to water are often invisible, campaigns to increase people's understanding of the value of tap water will prove to be important.

Normalizing a culture where returning nutrients back to the soil and food production is evident will prove to be the most important for nutrient cycling, soil quality and successfully integrating dry toilets in urban areas. 

Change the way we look at toilets from an object that gets rid of our waste to an object that collects, sorts and recycles waste.

Change of culture where reuse of feces is more accepted by the general public this can be encouraged by doing more research about waste treatment methods and developing better ecological toilet systems.

Research and policy attention should shift from pollutant removal (end of pipe solution) to resource-oriented management (preventive solution at the source). To envision human excreta as a resource is a way to off-set some of the fertilizer needs and reduce the pressure of nutrient pollution to freshwater and marine environments (Evgenieva Kelova, 2022).

To envision human excreta as a resource is a way to off-set some of the fertilizer needs and reduce the pressure of nutrient pollution to freshwater and marine environments (Evgenieva Kelova, 2022).

Society needs to learn to see the soil as more than just a medium to be manipulated, but as an ecosystem to be nurtured (“Dirt” - a New Documentary About Saving Our Soil, 2022).

The purpose of farming shouldn’t be profit or generating the biggest yield. The purpose of farming should be to strive to be the best stewards of the land to protect the ecological ecosystems farming depends on allowing farmers to grow big yields, bigger profits and nutritious food.

The purpose of toilets shouldn’t be to flush away waste but to separate the waste from the source and reintroduce nutrients back to the environment where they came from.

In order to safeguard sustainable use of renewable resources, negative feedback loops need to be in place. The negative feedback loop kicks in before the resource is depleted (Garrett Hardin).

Communication and educating the population about the benefits of recycling waste instead of discarding it into the landfill.

Exclusive partnership with one waste management company eases the administrative burden for cities and municipalities. Making it easier for the city to align and collaborate with a waste management company on long term goals (CNBC, 2018) to decrease waste disposal or lower water consumption.

Open conversation between policymakers and farmers need to be stimulated. Instead of top-down governing, grassroots change from the bottom up is a better approach. Welcoming pilot projects that aim at testing and developing new methods of farming.

To motivate people to transition to dry toilets it is estimated that they can cut their sewer fees by 50% (Petter D. Jenssen).

To encourage composting, recycling and composting needs to be mandatory. Trash collection rates should be set much higher than recycling and composting rates to encourage composting behavior. Collection rates for residents and businesses should be determined by the volume of waste. Businesses should receive discounts for using compost or recycling bins and penalized if recyclables or food scraps end up in the trash. Economy and environment need to reinforce each other instead of treating them as separate entities (CNBC, 2018).

Manual crop farming is more productive as plants can be planted closer together and the fields are more efficiently used. With manual crop farming you can yield 50 kg/m3 of potatoes compared to 35 kg/m3 with industrial farming (Petter D. Jenssen). 70% of food in the world is produced on small fields, not industrial fields. Transitioning to regenerative agriculture is the way to go (Petter D. Jenssen).

Ecological sanitation systems should be designed with user friendliness in mind to ensure a short learning curve and integrate the toilet system in the user’s daily life to the point that it becomes second nature.

Usually a new toilet system demands a change of habit, just as recycling of trash did in the past. As people became aware that recycling trash is good for the environment and a responsible way to run their homes they adopted the new habits over time (Margel, 2023). The same change of mindset is needed to get the public acceptance to successfully integrate ecological sanitation in homes and urban areas (Margel, 2023) because people realize how they contribute to a cleaner environment and healthier soil by using a toilet system that uses no water and returns nutrients to the earth.

To truly strive for sustainable living, nutrient recycling in addition to the reduction of freshwater use and consumption is fundamental (Kaur Bhatti, 2021).

Next I have illustrated 10 different integration solutions for ecological sanitation in urban and rural areas both centralized or decentralized for the Klaro, diverting compost toilets and incinerating toilets.

A more complex wastewater treatment plant that treats human waste, urine and gray water separately can provide unique treatment for each separate resource. The composting process is explained in greater detail in the illustration. Composting facilities can also be an engine for job growth.

Although the flush toilet is convenient to use, it is very resource intensive to run and to clean the effluent water because nutrients and biosolids are diluted in the water, which makes it hard to retrieve the nutrients for recycling and reuse. Flush toilets are one of the highest water consuming household products therefore it is a good candidate to replace to decrease your water consumption, electricity use, costs and environmental impact.

To replace the flush toilet three ecological toilets have been selected for this study. From the three toilet systems in this academic study the incinerating toilet is the system that is best suited for both low density rural areas and high density urban areas. Because it is a user friendly system, it requires no handling of waste and the ashes can be handled like any other organic compost matter. Unlike the other toilet systems it doesn’t require a lot of space, only a power source. Although safely removing medication residue and pathogens the incineration process does decrease the nutrient level in the ash. That’s why the diverting compost toilet came in a close second place as it does produce a safe high nutrient end-product; the only downside is the space and know-how needed to successfully get the desired result out of the composting process. This makes the diverting compost toilet less suitable to integrate in high density urban areas. The vacuum toilet is a complex system that makes obnoxiously loud noise when flushed, it has a lot of moving parts, it requires a septic tank and relies on electricity to run. This makes the vacuum toilet the least desirable of the three.

Needless to say ecological sanitation requires wastewater plants to adapt as the waste doesn’t contain any water. Therefore a composting treatment plant is needed that sifts, pasteurized and cures the organic waste. In case dry toilet systems would be implemented in large numbers in urban areas, it is the composting treatment facility that avoids the accumulation of waste and spreading of diseases, by collecting it at a central collection point and treating it for safe reuse on crop fields.

Ecological sanitation and the reuse of nutrients in human waste in agriculture has the potential to make countries more resilient when facing unforeseen circumstances such as supply chain issues and  fluctuating prices as a consequence of the pandemic or Russian invasion. Thus making a nation less dependable on imported goods from other countries, decreasing political pressures and increasing its self reliance.

Any sustainable solution that might be introduced in the future relies on a change in culture, a change in societal norms and user acceptance of the sanitation system. A holistic approach is important when implementing a sanitation system, to make sure that no unexpected problems come up during installation and implementation of the system.

Research so far aimed at limiting the nutrient and pollution load of the effluent, fortunately now research and policy attention is shifting from pollutant removal (end of pipe solution) to resource-oriented management (preventive solution at the source) (Evgenieva Kelova, 2022).

To envision human excreta as a resource is a way to off-set some of the fertilizer needs and reduce the pressure of nutrient pollution to freshwater and marine environments (Evgenieva Kelova, 2022).