Aims

By using primarily the ordination methods described in Chapter 2, the following key questions about the AS of 32 Danish wastewater treatment plants (WWTPs) will be investigated. Different types of ordination methods and distance measures will be used to describe the general differences in the microbial community composition of the AS of the WWTPs:

• Are there significant differences between Danish wastewater treatment plants with respect to the microbial community composition of the activated sludge?
• Are there microorganisms that are generally abundant in most or all treatment plants or microorganisms that are characteristic of individual treatment plants?
• Does the way in which the treatment plants are designed seem to influence the structure of the microbial communities?
• Are the microbial community composition stable over time?