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Summary and conclusions

Summary

This project gathers user experience concerning the establishing and running of 89 diverting/no-mixing toilet systems without water flush for separate collection of human urine and human faeces in allotment gardens.

Further, the measurements of chemical and microbiological parameters of the collected urine are discussed.

It has not been possible to achieve a permit to use human urine as fertilizer in the individual allotment gardens.

The introduction describes the background for the Danish Allotment Garden Associationīs interest in testing diverting/no-mixing toilets without water flush, as an alternative to both chemical abd water flushing toilets with sewer or collection tanks. The Danish Allotment Garden Association wished to test the toilets as well as the handling of human urine and human faeces in the individual gardens. The Association was inspired by the positive experience gained during practical the use of diverting/no-mixing toilets without water flush in Landskrona in Sweden. The Swedish rules permit use of human urine as well as composted faeces as fertilizer in the individual garden.

The history of the Danish allotment gardens and their organization is presented. The allotment garden movement has for a long time been an important part of the Danish everyday life. Allotment gardeners are known far outside the Danish borders for their pleasant lifestyle and for their great creativity by few means. This lifestyle is hampered by the more and more regulated society.

Chapter 2 reports on ten participating local associations in the three municipalities Ballerup, Herlev and Slagelse. The participating associations in Ballerup municipality were Brøndgården, Hestholm, Højvænge, Kildegården, Rønhøjgård, Stuvehøjgård and Tjørnebjerg. In the municipality of Herlev the following local associations participated: Klausdalsbro and Nyvang, and finally Østervang from the municipality of Slagelse.

In chapter 3 a short introduction to traditions related to the handling of human waste products/residuals is given. The chapter continues with a short characterization of human urine and faeces. Furthermore, the handling of urine and faeces in the project is described. The planned usage of human urine as fertilizer was not possible, due to existing regulation of the disposal of waste products. Existing rules on current burying of urine and composting and burying or direct burying of faeces are mentioned. Swedish recommendations regarding handling of human urine in e.g. allotment gardens are presented.

In chapter 4 earlier investigations on the subject are discussed. Some investigations concerning source uniting composting toilet systems and source uniting dry closets have been made, although only limited experience has been described regarding source diverting/ no-mixing dry closets.

Chapter 5 describes the eight different types of diverting dry closets and the two urine containers among which the participants in the project could choose. A description is then given of the sampling, the measuring program and parameters to be investigated. The parameters included nutrients, heavy metals, organic compounds as well as microbiological parameters.

The methods used to collect user experiences are described. The ten allotment garden associations are classified by numbers and sizes of the gardens. Garden sizes were generally 390 – 400 m2. The age and the sex of the users, and distribution among the allotment gardens, are stated. 80 allotment garden houses have altogether 176 permanent users, slightly more women than men. 27 permanent users were under 18 years of age, and 13 of those were under the age of six. Answering a questionnaire, 34 participating gardens responded that they used the allotment garden 60 – 230 days a year. The gardens were in average used 145 days a year. Further the chapter focuses on the toilets previously used in the allotment garden houses. The most commonly used toilet was a chemical toilet. 55 out of 81 toilets had been chemical.

Finally, figures for water consumption are given. Very few allotment gardens have water meters. The water consumption, including water for garden irrigation, was 4 – 20 m3 in five allotment gardens, with an average of 11 m³/garden.

The final choices of toilets by the participants are stated in chapter 6. Most frequently a "Separett Weekend", 37 out of 89, was chosen.

Chapter 7 shows that 80 participants preferred 25-litre urine containers and only 9 the big 220-litre containers.

In chapter 8 the 10 households delivering urine mixture for sampling and analysis are described. The households are described with relation to numbers of permanent users, age, sex, type of toilet, urine container, efficiency of the source diverting system and the frequency of emptying the urine container. The results of the chemical and microbiological analysis are presented.

The urine mixture was highly concentrated, with a concentrations of 5,400 mg N, 360 mg P and 1,100 mg K per liter. The concentrations of heavy metals were very low, much below the limit values given in the sludge directive, and also much lower than the contents found in other organic fertilizers. The concentrations of the investigated organic compounds were also low, much lower than the limit values.

There were no findings of bacterial infectious matters, such as Campylobacter or Salmonella or parasitic infectious matters such as Cryptosporidium parvum, Giardia duodenalis or other intestinal parasites, in the urine mixture from any of the 10 households. Amounts of thermotolerant coliforms were already during the first sampling below the detection level (10 cfu/100 ml) for 9 of the 10 urine mixtures. The sample in which thermotolerant coliforms could be detected was below the detection level at the second analysis approximately one month after sampling in the allotment garden. Amounts of enterococcus were below detection level (10 cfu/100 ml) for five of the urine mixtures at the second analysis approximately one month after sampling. At the third analysis approximately two months after sampling additional four samples were below detection levels. In the last urine mixture the amount of enterococcus was not detectible at the fourth analysis after approximately three months. pH was from 8.8 – 9.2.

Results of the investigations of user experience gained with establishing and running the toilet systems are presented in chapter 9. Experience from installation and running of 81 toilet systems are reported. Installation of toilets, ventilation systems, and urine systems with 25-litre containers, was generally quite easy. To dig down 220-litre containers required more work and efforts. Experience from the running of the faeces system, the urine system and the ventilation system are reported. The experience gained was been positive.

The comfort of sitting on the toilets was reported in only positive terms by 63 users (nine users had provided foot stools on their own). All of the participants using toilet models with sitting heights of 40, 42 and 46 cm were satisfied. More different opinions were expressed regarding sitting heights of 49, 50 and 53 cm without stools, 18 of these users would prefer a stool.

The function of diversion of the urine to the urine collecting system was only reported inconvenient by two women. However, it is reported that 11 women had to get acquainted with and adjusted to the system in order to achieve a god diverting functioning. Men and children at the age of seven or older had no problems. Experience with children under the age of seven was varied. 5 out of 24 children found it difficult to divert properly. The 5 children were: a 15-month-old boy, three girls of three and a half, four and five years and a child at the age of six with unspecified sex. 7 children at the age of 5 or less managed fine.

3 out of 77 users only reported cleaning of the toilets as slightly difficult or difficult. The rest of the participants found cleaning to be trouble free. Regarding problems with noise, only 1 participant could occasionally hear an irritating sound from a 19 W fan. Nobody with fans had problems with smell in the toilet room. Some users without fans could experience some smell problems, but not enough to make them install a ventilation system. 2 users had big problems with flies, but the problems were solved by means of continuous running of the fan, as prescribed in the manual, and by use of a fly net at the end of the ventilation system and on the inlet to the urine container.

Reported experience with the handling of urine and faeces showed no problems concerning urine and 76 of 77 users characterized emptying of the faeces container as unproblematic. One participant found the smell unpleasant but acceptable. The frequencies of emptying the faeces container are reported for the different models. The frequencies were from every three to six days, to once a season depending on toilet model, size of the household and use of the toilet.

Generally the interviewed participants characterized their impression of the toilet system as positive or very positive.

49 participants had positive or very positive reactions from guests, neighbours or others. 3 participants had seen negative reactions. 26 participants proposed amendments, 9 participants with sitting heights of 50 cm or more would prefer lower sitting height.

Conclusions

Diverting/no-mixing toilets were installed in 89 allotment gardens in the municipalities of Ballerup, Herlev and Slagelse. The purpose was to allow the users to evaluate the system regarding installation, diverting, usage, cleaning, emptying, and possible inconveniences. A broadrepresentative section of the inhabitants participated in the tests. The users were very positive and only had very few problems; all of them were solved during the project. Installation, cleaning and emptying of the toilets are considered easy to manage. One user had problems with installation of a 220-litre container due to high ground water level.

The daily use of the toilets is without problems, but some women find it difficult to hit the urine bowl. After a period of training, only two women still had problems. Inconveniences like flies, noise and smell were negligible and the users solved the few problems themselves. There has been some smell problems at special wind directions, at five of the users who had decided to take the ventilation out of the wall instead of up through and over the roof. Only two users considered the problem big enough to make it worth changing the ventilation system.

The collected urine was very concentrated due to limited use of water. At the same time the concentrations of heavy metals and organic compounds were far under the limit values given in the sludge directive. The collected urine is well suited as a fertilizer.

In the analysis of the collected urine mixture no bacterial or parasitic infectious microorganisms were found. The following species were investigated: Campylobacter, Salmonella, Cryptosporidium parvum, Giardia duodenalis and other intestinal parasites. Thermotolerant coliform bacteria were only present in one of the 10 samples from the 10 different urine containers and disappeared after one month. The amount of enterococcus is below the detection level for this urine mixture after three months of storage.

Usage of stored human urine, as a fertilizer, seems to involve a very small risk for bacterial-related stomach intestinal infections to animals and human beings by handling of human urine and by consumption of crops fertilized with human urine (Dalsgaard & Tarnow 2001).

The test of diverting/no-mixing toilets in the allotment gardens was a great success, and the systems are excellent alternatives to traditional systems. The advantages by establishing diverting toilets above solutions with sewers are among others water savings and recycling of nutrients. Furthermore, considerable economical advantages are achieved for the allotment gardens, compared to installation of much more expensive solutions with sewers. The results from the microbiological analysis indicate that the urine can be used as a fertilizer in the garden instead of being dug down.

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