Populett in the Nuuksio national park

Principles of sustainable nature tourism are applied in the destinations managed by the Board of Forestry. Each year about 180,000 hikers visit the Nuuksio national park, which is one of the parks managed by the organisation. The area is appointed with a variety of services. The number of toilets in the national park amounts to about 30. Each camping site, campfire area, cooking shelter and lean-to is furnished with a dry toilet. In addition, there are dry toilets next to the nature hut by Haukkalampi pond and at Kattila.

Two of the dry toilets are 300-litre Biolan Populetts, and one is a 200-litre Populett. The large Populett dry toilets were brought into use in Nuuksio in 2008, while they were still in the product development stage. They weren’t introduced on the consumer market until later.

According to the ranger of the Nuuksio national park, Mr. Antti Raita, the Populett has also attracted growing interest from other national parks.

The toilets in the Nuuksio national park are frequently used.

"The Populett toilets are operating excellently"

According to Mr. Antti Raita, ranger of the Nuuksio national park, the Populett dry toilets have met all expectations invested in them.
- They operate extremely well and reliably and are easy to maintain. In addition, they are convenient to use, says Mr. Raita.
- All one has to do is add some bulking material, advises Mr. Raita.

"Easy and neat"

The two 300-litre Populett toilets of the Nuuksio national park are placed side by side in the toilet building located on a gentle slope.
- The toilets and the toilet building look as if they have “turned their back” to approaching people. According to Mr. Raita, the slight height difference is an advantage, as it means the liquid flows more rapidly past the compost mass into the closed tank next to the building. 
The waste container is easy to empty through the hatch in the rear wall of the wooden toilet building. The waste is taken for post-composting to the large composting tank built in the area, which consists of three compartments In two years the Populett toilets have been emptied five times and the closed tank only once, because most of the liquid is evaporated during the composting process.

Maintenance work on the Populett toilet is easy through the rear hatch.

Odours are eliminated by means of efficient ventilation.

The Populett is favoured by hikers

The Populett toilet is highly rated by the guide of the Nuuksio national park and the hiking group.
- Myself, I use these toilets the most and I have noticed that they are also favoured by hiker groups. These toilets are always tidy, irrespective of the season, says Ms. Katja Kotkas, who represents Green Window Oy, a company operating in Nuuksio.

What about odour?

- Funny, I haven’t even thought about it. I think that this must mean that odour is not a concern in the Populett toilets!
The locks of the national park’s toilets are fitted with counters. These are used to track how frequently the toilets are being used. The counting is still in progress.

The guide of the nature tours Ms. Katja Kotkas (on the left) and female hikers give the Populett toilets full marks for tidiness and functionality.

The guide of the nature tours, Ms. Katja Kotkas, says that she always advises hikers to use the Populett toilets, whenever possible.

Back to nature

Valuable nutrients of the waste from the dry toilets are returned to natural circulation by composting. The urine and the seep liquid are excellent nitrogen fertilisers for the garden. Seep liquid can also be used as compost starter. Unfiltered liquids load the soil and may leach into nearby bodies of water, ground water or wells. Along with phosphorus, nitrogen eutrifies the bodies of water.
The purity of nature is fostered in the Nuuksio national park. This means, for example, that toilet waste is carefully collected.

Before use

Put a layer about 5 cm thick (about 20 l) of Biolan Compost and Toilet Bulking Material onto the intermediate bottom of the Biolan Populett in order to prevent the liquid separation system from getting clogged. If the toilet is to be used in urine-separating mode, the separating flap shall be set to direct flow into the separating pipe. If the unit is to be used in seep-liquid-separating mode, the flap shall be left so that it closes the separating pipe.

Adjusting the air valve in the seat top

Ventilation of the Populett Toilet is controlled using the replacement air valve in the seat top. During summer the valve is kept open which makes the ventilation more effective and the evaporation of liquids more efficient. During winter the air valve is kept almost closed, which reduces temperature loss from the composting mass. Keep the thermal seat lid closed, when the toilet is not in use, to ensure correct operation of the ventilation.

What can be placed in the Populett toilet?

The Populett is intended for composting toilet waste. Do not put into the unit anything that hampers the composting process or does not compost, such as:

• debris, sanitary towels
• chemicals, lime
• detergents, washing water
• ash, cigarette butts

Using bulking material and the Compostmixer

Every time after using the toilet, add approximately 2-5 dl of Biolan Compost and Toilet Bulking Material over the excrement. Applying suitable bulking material is essential for proper operation of the toilet. We recommend using the Biolan Compost and Toilet Bulking Material as bedding. This efficiently absorbs odours and keeps the toilet compost airy. To extend the emptying interval of the toilet, use the compostmixer to loosen the toilet mass and to smoothen out any uneven filling. Move the compostmixer inside the mass to and fro several times in all directions Use the compostmixer as required, however at least after every 10-15 times of use. After use, leave the compostmixer in its lower position in the ventilation pipe.

Year-round use of the toilet

The toilet waste freezes in frost. Freezing damages neither the unit nor the compost mass. Decomposing of the compost mass will continue when the air temperature rises. The capacity of the toilet can be increased by utilizing the urine-separating functionality of the Populett. The liquid tank shall be emptied in the autumn. Its filling level shall be observed to prevent it from cracking due to freezing.

Emptying

The Biolan Populett shall be emptied when it fills up. The unit shall be emptied completely. The emptying shall be carried out either by shovelling, by turning the body of the toilet upside down, or by tipping it over using the tail lift of a waste truck. The Populett toilet is fitted with a bracket for the waste bin lift of the truck.

Emptying:

1. Remove the thermal seat and the sealing strip or cover from between the wall and the unit, if installed.
2. Take the liquid hose out from the canister/tank and fix it to the hose bracket by turning.
3. Pull the compostmixer to its rear position. 
4. Disconnect the air pipe from the toilet unit by lifting.
5. Pull the unit out of the building.
6. Tilt the unit so that you will be able to put the shaft with wheels in place.
7. Transfer the unit to the emptying location or leave the mass inside the tank for composting and replace it with a new tank.

We recommend that a toilet used only in the summer be emptied in the spring, before using for the first time. The emptying process is most convenient and easiest at this stage.

Emptying the seep liquid canister

Empty the seep liquid canister as required, however, at least once a year. Seep liquid, rich in nutrients, can be utilized as a source of nitrogen for compost. In particular, this improves the composting process of garden compost that is rich in carbon but poor in nutrients. Seep liquid can also be used as fertilizer for ornamental plants in the yard and garden. A safe dilution ratio is 1:5. Undiluted seep liquid can also be used, but the area must then be carefully watered after the application to avoid early blight. Fertilizing in the autumn is not recommended so as not to disturb the preparation of perennial plants for winter. The recommended storing time before use as fertilizer is approximately one year.

Cleaning

The thermal seat of the Populett can be cleaned using any common domestic cleaning agents. The liquid pipe and the liquid trough under the intermediate bottom shall be checked once a year and cleaned as necessary. There is no need to wash the toilet tank in connection with emptying it.

When locating the Biolan Populett, it is essential to provide sufficient space for use and maintenance of the toilet, for installation of the toilet through the wall of the toilet building, and for routing of the ventilation pipe. How the seep liquid or the seep liquid and urine shall be conducted into the tank or relevant treatment facility also needs to be taken into account. The unit can be placed directly onto ground of sufficient firmness. Before building the toilet, it is a good idea to plan the access route required for maintenance behind the toilet and for the post-composting procedure.

It is possible to install the Populett in an existing toilet building taking into account that the structure of the building must be modified in order to enable correct positioning of the toilet unit. When planning a new toilet building, the space requirement of the toilet needs to be taken into account.

Placing in the toilet space

It pays to make a smooth and durable bed for the toilet, such as for example a gravel bed, covered by film-faced plywood or a concreted bottom structure. While creating the openings and bottom structure of the building, it also pays to occasionally put the toilet in place so as to find out where the openings still need to be reworked. Using the sawing template and the dimensions provided as an aid, a suitable opening for the toilet is sawed in the floor and in the wall. Depending on the manufacturing technique, the size and shape of the tank may vary slightly. This means you may have to enlarge the hole a bit or the seam of the floor and the tank will not be completely tight. Avoid, however, making the openings too large, because a too-wide chink between the toilet building and the toilet unit is not a good thing.

An easy-to-remove wooden strip or a rubber cover that gives way as the toilet is removed from the building can be installed to cover the space between the rear wall of the toilet building and the toilet unit.

Installing the ventilation pipe

The seat top is provided with a Ø 110 mm hole for the ventilation pipe. The compostmixer is installed between the ventilation pipe and the toilet unit. The ventilation pipe is routed without bends from the toilet unit above the roof ridge along the wall either passing the eaves or through the roof. Seal the lead-through on the roof using a sealant suitable for the roofing material. If you have to make some bends, take note that the curvature of such bends must not exceed 33 degrees. Any bends in the ventilation pipe impede natural ventilation, causing odour and moisture problems.

Populett 200: Press the ventilation pipe cap onto the end of the pipe to ensure that neither rainwater nor flies can enter the toilet. To improve the ventilation and the evaporation of moisture, use the Biolan Wind Ventilator, available as an option.

Routing the liquids

Separating the urine

The structure of the Biolan Populett’s front edge enables partial separation of the urine. For separation the transparent separating flap at the front edge is shifted to form a funnel leading to the separating pipe. During winter use, the separation reduces build-up of mass susceptible to freezing. As urine is directly conducted away, it will not be absorbed by the bulking material and freeze. Although the Biolan Populett is set to separate urine, seep liquid will also come out of the unit. It is conducted out of the unit together with the urine. If the Populett is set to separate urine, more liquid will be created for collection and treatment. This needs to be taken into account when dimensioning the treatment system. In a toilet that separates urine, the mass remains dryer, which makes emptying the toilet easier.

Separating the seep liquid

It is possible to operate the Populett in a mode in which it only separates seep liquid. The separating flap at the front edge is left in front of the separating pipe so that it directs the urine into the toilet waste. The excess fluid that is not absorbed by the bulking material or the toilet mass is separated by means of the intermediate structure of the bottom. Thus less liquid but more mass will be created in the toilet, especially in winter, compared with working in urine-separating mode.

The liquid pipe is connected to the liquid removal hole in the rear wall of the toilet. The pipe is conducted to the collecting tank or the liquid shall otherwise be treated in a due manner. Bury the collecting tank in the ground, or position it in such other way that the liquid flows under gravity into the tank. If using the Populett in urine-separating mode, conduct the liquid pipe to the bottom of the canister so that the surface of the liquid forms a drain trap. Take into account possible use in winter when laying the liquid pipe and locating and insulating the tank.

If it is difficult to bury the collecting tank in the ground, it can be replaced with an evaporating pan. To reduce the liquid volume, the Populett is set to work in the mode in which it separates seep liquid. Place a rain lid above the evaporating pan – non-fertilized peat is recommended for the neutralisation of odours.

Product data

Dimension drawings

• volume: about 200 litres
• seat height: 48 cm
• height: 93,5 cm
• weight: about 50 kg
• diameter of the outlet air pipe: 110 mm
• diameter of the liquid removal pipe: 32 mm
• colour: brown