Greywater Reuse in a Four Star Hotel

Simplified flow diagram

Hotel Am Kurpark Späth, Bad Windsheim

In 2008, a water recycling system was retrofitted in the four star hotel "Am Kurpark Späth" in the Franconian spa town Bad Windsheim. All 20 rooms in the seminar building have been connected to the grey water cycle. The low polluted greywater from wash basins and showers is collected separately and treated to obtain hygienic service water for toilet flushing.

It is planned to also reuse in the future the so-called white water (high quality service water) for the first stages of washing in dish washers and washing machines.

A mesh screen removes from the inflowing greywater the disturbing materials, such as hairs. The treated greywater flows into an intermediate storage tank. The heart of the treatment plant is the MBR unit, a combination of the activated sludge process and membrane filtration, with membrane modules for ultrafiltration being submerged directly in the aeration tank. The pollutants contained are decomposed by the efficient aerated sludge biocoenosis. The following membrane filtration unit separates the treated greywater from the activated sludge.

The permeate, which is free of solids and bacteria and virtually all viruses, is stored in the service water tank. To prevent recontamination a further treatment step is added, namely disinfection with UV radiation. After such treatment the service water meets the microbial quality according to the requirements of the Drinking Water Ordinance (attachment 1 of TrinkwV, part 1, 2001; table 1).

Service water supply to the consumers is achieved by means of a pressure increasing plant. All operating parameters are transmitted online. Fault reporting via SMS is available.

Operation and maintenance:
Inspection and maintenance intervals: annually
Operating experience, operating years: 1
Inspection and maintenance work: approx. 8 working hrs/a

Parties involved:
Planning: RWTH Aachen / Hans Huber AG
Plant supplier: Hans Huber AG
Plant operator: Family Späth