Ban on the use of sludge as a fertiliser

Bern, 26.03.2003 - The use of sludge as a fertiliser is to be banned throughout Switzerland; in the future sludge will have to be incinerated using an environmentally friendly method. The Swiss Federal Council will modify the Ordinance on Materials accordingly on 1 May 2003. The ban will be introduced in stages: from May this year, sludge may no longer be used in the production of fodder crops and vegetables. A period of transition lasting until 2006 at the latest has been accorded for other types of cultivation which until now have been fertilised using sludge; in individual cases the cantonal authorities may extend this period until 2008. This decision is part of the Federal Council’s implementation of precautionary provisions for the protection of soils and public health.

Although sludge contains plant nutrients such as phosphorus and nitrogen it also comprises a whole range of harmful substances and pathogenic organisms produced by industry and private households. For this reason, most farmers already avoid using sludge as a fertiliser since they are aware of the risk of irreversible damage to the soil, the danger to public health and possible negative effects on the quality of the food they produce. 

For this reason the Federal Council plans to ban the use of sludge as a fertiliser, although this will mean breaking a nutrient cycle which is in itself useful. Prevention – a key principle of the law on health and the environment – requires, however, that any consequences for the environment which could be damaging or negative must be limited as early as possible, even there is no conclusive scientific evidence for such damage being caused. 

Period of transition and exceptions to the ban

The ban will come into force for the production of fodder crops and vegetables on 1 May 2003; this sector represents the greatest risk to the health of humans and animals. The ban will apply to all other types of cultivation from 2006 on. The period of transition may be extended by the cantonal authorities until autumn 2008 at the latest. Exceptions to the ban will include very small sewage treatment plants in remote areas. In such cases, sludge normally contains fewer problematic substances and the cost of transporting it to a larger treatment plant would be disproportional. 

Today 60% of all sludge is already treated as waste. From 2006 on the remaining 40%, i.e. a further 80,000 tons per year, will also have to be incinerated. The additional cost that will be involved is estimated to be around Sfr. 40m at the most. This sum would in any case need to be paid in a few years’ time since, even without the new ban, sludge would gradually be abandoned as a fertiliser. The ban on the use of sludge will therefore enable the cantonal authorities and sewage treatment plants to make more reliable long-term plans. 

The consultation process revealed widespread approval for the ban: most of the cantons and farmers’ and commercial associations as well as consumer and environmental organisations responded positively. The opposition camp was led by the Association for the Sustainable Use of Ecological Resources, founded in May 2002 in relation to the proposed ban, which comprises mainly small and medium-sized sewage treatment plants.


Continued use of recycled substances as fertilisers – from compost or fermentation residues

The ban on the use of sludge does not mean a general stop to recycling substances for use as fertilisers, but rather a further improvement of the quality of other fertilisers from recycled sources such as compost or fermentation residues so that they can be safely used as fertilisers or soil improving agents in agriculture. In comparison, compost is highly suitable for recycling as a fertiliser since it is based on vegetable matter, which means that, in contrast to sludge, there is no risk of undefined pollutants from waste water. 

In order to improve the quality of compost, the Swiss Association of Compost and Fermentation Plants (ACFP), together with the Swiss Agency for the Environment, Forests and Landscape (SAEFL), the Swiss Federal Office for Agriculture (FOAG), cantonal environmental offices, research institutes and the agricultural sector, is planning to set up a special monitoring office whose job it will be to ensure that all the 300 or so compost plants in Switzerland comply with the legal minimum quality standards. 

Furthermore, the ACFP has drawn up more stringent quality criteria for the use of compost in agriculture, market gardening and greenhouse cultivation. Its members have undertaken to respect these criteria in the future. At the same time, two research projects are being carried out at a federal level, which involve an in-depth investigation into pollution through compost used as a fertiliser on the one hand, and identifying the advantages in relation to the quality and use of the soil on the other.


Federal Department of the Environment, Transport, Energy and Communications