This report contains the results of the work with selected action areas within the bus operation industry with a view of reducing the bus companies’ environmental impact and resource consumption. The action areas were chosen in a previous project, in which the environmental impacts when preparing and maintaining the busses of the bus company "Århus Sporveje", were mapped out. The report primarily aims at traffic companies whose activities are similar to those of Århus Sporveje, i.e. busses. 

At the beginning of the project it was expected that a concept for the recycling of wash water with the possibility of using rainwater as additional water would be developed. It was also expected that the sustainability of the concept should be demonstrated. However, the use of rainwater as additional water was given up at an early stage, as it was considered uneconomical. After having obtained offers for the establishment of a recycling plant on the basis of a specification of requirements, it turned out that the sketched recycling concept was not competitive with an already existing English recycling plant according to price, as the plant had to be delivered and build up as a turnkey plant. However, the existence of the English plant was unknown to the participants of the project at its outset.

Nevertheless, the English concept turned out to cause problems under Danish conditions in spite of many years’ work experience from hundreds of plants in England. However, the problems were solved gradually, primarily because of the extraordinary efforts that were made by the Operations Manager at Århus Sporveje.

The conclusion of a survey at Århus Sporveje’s Station NORD is that an abnormal large consumption of motor oil under operation is caused by the following factors:

	The engines are overfilled with motor oil (even though it was not proven in the actual case)
	The tolerances in the engines are relatively large (mostly seen in engines of an earlier date)
	Lack of tightness in the engines, which causes oil spillage.

Ten years ago the consumption of coolant dropped drastically because silicone tubes for the flexible connections in the cooling/heating system were taken into use instead of rubber tubes. At that time the consumption dropped to the level, which is normal today.

About 20 different tubes, e.g. 40 connections for metal tubes in varying dimensions forms part of the cooling/heating system of an ordinary city bus. An investigation shows that spillage of coolant primarily takes place during the driving because of lack of tightness by the tube connections and in the cooler.

A common notion is that the bus’ fuel consumption above all depends on the driver’s attitude to economising on fuel and to environmental conditions. Several bus companies consider it a good idea to encourage drivers to attend fuel economical driving courses. However, the results of the courses are only short-lived. It is therefore necessary to arrange brush-up courses for the drivers at regular intervals.

Tools for learning fuel economical driving are flowmeters or driving computers, which indicate the bus’ actual fuel consumption while driving. In this way the driver will learn which ways of driving that result in fuel consumption above and under average, respectively.

According to DTI’s (the Danish Technological Institute) Motor Section, tires and treads with a lower rolling friction can easily be developed. Today such tires are marketed for cars, but not for busses and trucks, which is due to the fact that so far no bus company or any firm of hauliers has taken any interest in the tires.

Furthermore, it was discussed in the project’s reference group to use small busses at the times of the day with few passengers. The report contains a description of advantages and disadvantages of using small busses and an evaluation on whether such action is appropriate in reality.

Århus Sporveje decided to participate in a refuse disposal system after having considered the advantages of the system. Economically hardly any advantage was derived from the system, but by leaving the refuse disposal to an external professional firm, working hours are saved and the refuse disposal is taken care of in a proper manner.

Advertising streamers are solely made of PVC, which is considered incombustible refuse. The local refuse disposal plant refuses to burn PVC due to the risk of dioxin contamination. It is said that certain companies do not wish to use advertising on busses as long as PVC foil is used for the purpose. A survey among suppliers of PVC foil shows that the foil industry expects to be able to offer a PVC-free foil within two years.

Århus Sporveje has become a positive feed back on the cleaning materials that are used today. As the participating parties considered a change to other cleaning materials a problem for the cleaning personnel, it was not possible to launch an investigation into this matter.

Author/ institution

Jens Wood Pedersen. DTI Miljø. Center for Miljøteknik. 

This report is subsidised by the National Council for Recycling and Cleaner Production 

ISSN no. 0908-9195
ISBN no. 87-7810-726-1

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