PDF-format - Miljøstyrelsen

Summary and conclusionsIntroduction and ObjectivesThe present project was carried out in the period from October 2001 to June2002, presenting an evaluation of the full-scale tests completed, focussing oncollection, treatment and reuse of grey wastewater for toilet flushing carriedout in the period 1991-2001.The objective of the project was to collect information about and assess theDanish pilot plants in full-scale for reuse of grey wastewater for toilet flushing.The project is financed by the Danish Environmental Protection Agencywithin the framework of “Aktionsplan for byfornyelse ogspildevandsrensning” (Action plan for urban renewal and wastewater treatment).Greywater Treatment Systems in DenmarkIn the period 1991-2001 a total of 35 full-scale tests with collection, treatmentand reuse of grey wastewater were carried out; of these, 10 treatment systemswere established with reuse of greywater for toilet flushing.Only half of the established treatment systems is in operation in 2002, andseven active treatment systems with reuse of greywater for toilet flushing areregistered.Administration Practice in DenmarkAn opinion poll among large Danish municipalities shows that the municipaladministrations have granted nine exemptions for establishment of tests withgreywater treatment systems.However, generally it may be concluded that the procedures for considerationof exemption applications used by the municipalities differ. Furthermore, thepolled attendants called for instructions and / or technical directions specifyingthe requirements to be met in respect of greywater treatment systems.In the Municipality of Copenhagen a practice for consideration of applicationsis applied, and routine inspections are performed at the pilot plants.Main Findings from Technical EvaluationGenerally, it may be concluded that a number of different pilot plants havebeen established. The character of the pilot plants is a prototype plant tailoredfor the location in question. A few suppliers have tried to develop a “standardplant” with a view to obtaining a certification.Quite a few of the companies, who started the development of greywatertreatment systems five to eight years ago, have now stopped this activity.Based on the technical inspection of the seven active treatment systems theoperational status may be summarised as follows:13