Toilet composter

The Ekolet composting toilet is a patented product where also the purifying process is covered by the patent.

It is important for composting that the fluid reaches the solid substance and leaves it without a need for any additives. At the same time new moist and oxygen-rich air flows through the permeable base into the solid substance during the maturation phase. Good oxidization, correct humidity, and sufficient maturation time guarantee matured compost when the oldest compost compartment needs to be emptied for a new fill. Emptying takes normally place only after three years (one of four compartments in use per year). No such composting would take place if the solid substance would be stored in a closed container or if new waste would be continually added to it.

Lab analyses of the solid waste removed from Ekolet composters (normal use) have been carried out in the Finnish and Swedish Soil Analysis Services and there are official laboratory statements about them. In all, there are four analyses.

The fluid that has gone through the solid toilet waste and has been filtered out from it has released phosphorus and has been enriched with plenty of microbes. Pure urine does not contain these microbes required for purification. The purifying process starts from a flat, filtering permeable base and near it. After the filter the fluid falls to a flat liquids plate for oxidization and standing. After this the fluid falls further to a flat liquids plate for more purification. In a year round model (YV) the liquids plate is replaced with a large upright filtering cloth where the fluid flows slowly into the liquid compartment at the same time getting oxidized and purified. In addition to the aforementioned models, the YV-B model also has a bio filter (circa 50 l) high one meter through which the fluid pump circulates the liquid practically hundred times before it leaves from the composter’s outlet. In the aforementioned processes the fluid containing microbes receives plenty of oxygen and sometimes also suffers from anoxia, it mixes with the old liquid and sludge and is thus purified biologically as the process proceeds. No such purification would take place if the fluid would flow directly into a liquid tank.

The amount of liquid that exits the outlet of Ekolet composting toilets  (normal use) has been measured and analyses have been performed in several authorized water laboratories. The following has been determined from the liquids: pH, BOD7 +ATU, CODcr, total nitrogen, total phosphorus, ammonium nitrogen, faecal coliform bacteria (44.5 Cº). The analyses have been made according to the generally used standards. There are official laboratory statements about all the results that clarify, among other things, the used standards. Tens of specimens were examined.
In our web-pages ( the aforementioned analyses have been summarized by telling the amount of impurities remaining in the exiting liquid for a user per day (residue/pers/day).

The exiting contaminants (the purifying power) have been gained by comparing the aforementioned laboratory analyses of the liquid with properties of unrefined toilet waste.

In our web-pages we have settled for a summary of the lab analyses. Detailed information about the research, including laboratory analyses and statements, will be gladly provided on request. All the specimens have been taken from Ekolet composters during normal use, therefore the tests and received results are reproducible.

We have enquired from the representatives of central companies producing gray water treatment plants whether it hampers or weakens the cleaning result of their gray water treatment systems if pre-cleaned overflowing fluid (commensurate to the aforementioned residues) from an Ekoletcomposting toilet is added to the grey water (drop by drop some litres in a day). The representatives answered that it does not hinder purification. The final result meets even the tightest requirements of law provided that the quality of the exiting fluid can be checked, if necessary. On these grounds we dare to recommend the further treatment of fluids exiting the Ekolet composting toilet together with gray waters of the house.

In our opinion, remarkable environmental savings can be achieved this way as this eliminates the use of heavy tank wagons with their equipment and energy costs. Ekolet composting toilet`s operation is also reliable regarding the environment as all the composting and cleaning of the liquid takes place all the way in the composter without additives or need for external workforce. It is not possible, that the user neglects further composting, treatment of exiting fluids or dosing of additives. Ekolet composting toilet has been made of recyclable materials and designed to last for decades.
As stated before, the aforementioned test only concerns the properties and further treatment of the solid substances and liquid removed from Ekolet composting toilet.

Load calculation
All wastewater from the household when using the Ekolet four-compost compost toilet where out coming liquid is led to the household grey water treatment system. Load according to instructions: Year-round Ekolet YV for 6 persons / day and Ekolet VS for 4 persons / day during two summer months.

Load Organic Substance Phosphorous Nitrogen
 Incoming to the System g/pers/day % g/pers/day % g/pers/day %
Faeces 15 30 0,6 30 1,5 10
Urine 5 10 1,2 50 11,5 80
Other (washing water) 30 60 0,4 20 1 10
Total 50 100 2,2 100 14 100
 Outgoing from the System
Removed with the Compost 20 40 1,2 55 11,3 93
Removed by the septic tank
and shrub purification plant  25  50  0,6  45  2,0  5
Remains left 2,5 5 0,4 20 0,7 2
Remains accepted by Law*        10 20 0,66 30 9,8 70
Removed by the System
 48  95  1,76  80  13,3  98
Removal required by law* 45 >80 1,54 >70 5,6 >30

* In many EU countries

If it is a reasonably occupied holiday home, an alternative to the use of above-mentioned gray water treatment system, is to  infiltrate the naturally purified out coming liquid from the Ekolet toilet directly to the plants or bushes in the ground.

We will gladly provide additional information about Ekolet® products on request.

Yours sincerely,
Matti Ylösjoki, dipl. eng.,
Developer of Ekolet products

Please print out this report as a supplement to the application to be submitted to the authorities.