EN 
DE On behalf of Stadtwerke Rinteln, M&P Ingenieurgesellschaft and Sensatec GmbH are currently remediating the former gasworks site in Weserbergland in situ without having to restrict the current operations of Stadtwerke Rinteln. Two sources of damage were identified in the preceding soil and groundwater investigations. Innovative biological remediation by means of groundwater circulation is intended to break down the gasworks-specific pollutants cyanides, PAHs and NSO heterocycles in the water-saturated subsoil. By adding active substances, the existing microorganisms are stimulated and subsequently metabolise the pollutants.
Even unforeseen problems in the course of the project cannot stop M&P Ingenieurgesellschaft and the implementation of the planned sustainable refurbishment strategy.
Due to unexpectedly high localised concentrations of iron in the groundwater, the system technology is heavily affected by iron sludge. Ochre build-up and deposits on the pump housings and inside the pumps regularly led to a reduced flow rate, meaning that the circulation cells could not be supplied with sufficient oxygen and active ingredients. A bag filter with a mesh size of 65 microns was temporarily installed upstream in order to maintain operation. To counteract the general problem, the operating concept was revised in consultation with the lower water authority and four additional 6" groundwater measuring points were set up for infiltration. A gravel filter system was installed for the relevant remediation wells and the remediation infrastructure was adapted. One of the difficulties in constructing the gravel filter was the space required on an active municipal utility site. The plant consists of three filter towers connected in parallel and a storage tank. This removes the suspension load from the process water and prevents clogging.
Following the conversion of the system technology, the refurbishment can now be continued as planned and with correspondingly less maintenance-intensive work.
