Upgrading and retrofitting of municipal wastewater treatment plants by means of membrane bioreactor (MBR) technology

In the future, upgrading of existing wastewater treatment plants (wwtps) will become the more challenging task than erection of wholly new plants, as most of the plants (e.g. necessary in Germany) do exist already. Since some time, MBR technology has been taken into consideration and has been realised as an alternative for wwtp upgrading. This paper gives an overview about some relevant preconditions, basic upgrading concepts and examples of already upgraded wwtps using MBR technology.

The presented upgrading concepts raise no claim to completeness and thus reveal the wide spectrum of supposable measures. Many of them are under investigation and appropriate findings can be expected to be reported soon. However, the chosen upgrading concept must meet the claim to be • demand-oriented according the wastewatersided requirements and the load situation, • economical in view of annual costs (operating expenses and net debt service). Besides, various other, not only process-related, but also nonmonetary and monetary hardly assessable aspects are to be followed and to weigh in each individual case which do not admit a stan- conventional activated sludge process return sludge BOD sec. sed.