Studentenwerk Frankfurt - Treatment of greasy kitchen wastewater - Case Study
In many local authorities, the limit for lipophilic substances has been tightened from 250 mg/l to 100 mg/l. In such cases, a grease separator is not sufficient to ensure reliable adherence to this limit value.
The kitchen wastewater of the canteen is discharged via the kitchen's floor channels, and through the wastewater inlet to a curved hydro sieve, which separates out coarse solids down to a size of 1.5 mm.
The kitchen wastewater, now free from solids, then runs through a test section where pH and temperature are measured. The main stream of the kitchen wastewater is buffered and stored in a pressure-tight integrator. Potential system overloads and endangerment of all subsequent stages are prevented by the interception of wastewater load peaks.
The wastewater is pumped out of the integrator into two fermenter lines with two fermenters. Here, the grease in the wastewater is broken down by specialised bacteria. Both fermenter lines operate separately and are completely independent in their performance, to ensure greater operational reliability. During the individual process steps, which are tailored to the degradation process, the wastewater remains in the fermenters until the required level of degradation is achieved.
Following treatment, the wastewater is discharged into the sewage system by means of a pumping unit. An aftertreatment for pH regulation is not required with this system. No chemicals or other additives are used. No odours are generated.
- Volume of wastewater:
- Up to 5,000 l/day
- Up to 500 meals/day
- Output: Approx. 2m³/day per fermenter line
- Tank design: Plastic (PP)