This thesis describes the development of a device called "Oil Separator" which is used for washing vehicles and particularly car washing. The device developed for Mr. Car Bilvård AB in Uppsala, the company's work involves passenger transport and courier services. The company needs an external device that meets the environmental standards to wash their own cars in the premises without the need to modify or reconstruct on the premises ground as the premises is on a leased contract. Work began with a preliminary study on the literatures that describes both the function and structure of designing the device. A few interviews with other car wash companies had been implemented, and some measurements. After collection of the necessary information the specifications of customer requirement was presented . With these requirements a few concepts was generated and weighed using the Pugh matrix for concepts selection for further development. The final concept was further developed and a design has been presented. A design of the washing place was taken up also which does not require any change in the premises by putting it on the ground. A functional smaller prototype of the oil separator was developed and tested.

To avoid harmful substances it is important that emissions such as oil, gasoline, grease and sludge are cleaned by oil separators to reduce damage to the human health and the environment. But also to prevent high levels of oil from waste water to sewage treatment plants which can disturb the purification process. The aim with this work is to find out that the municipalities fulfill the requirements in the environmental framework. By supervising the 5-year inspection of oil separators according to SS EN 858 on the stormwater and wastewater network. To find out this, inquiries were sent by e-mail to all 290 municipalities in Sweden. The results show that the inventories of oil separators have not been carried out to the proper extent. The municipalities can follow the supervision pursued according to the environmental guidelines and environmental goals but an inventory is also needed to know how many oil separators are present in the municipalities. The oil separators are usually controlled with other supervisions. A 5 - year inspection of oil separators that were sufficiently good has only been made by 2 municipalities. 5 – year inspection must be carried out even if the operations have not been running for 5 years. The conclusion from this study is that oil separators have been a neglected area in most municipalities. Hopefully this inquiry can be a reminder to start with inventories in those municipalities.