Comparison of technology, costs and environmental benefit of wastewater treatment plants in mountainous areas in the alps

back

Berlin Refuge

Site description and boundary conditions
Design and treatment efficiency

Site descriptipn and boundary conditions

boundary conditions
maximum daily organic load [PE]	260
maximum hydraulic load [m3/d]	18
annual organic load [kg BOD/a]	700
altitude [m a.s.l.]	2040
sensitivity [hydrogeology, protected area ...]	granite, river
lagal requirements [BOD elimination]	80 %
operation period [season]	summer
energy supply [type, kW]	water power plant, 50
means of transport [type]	supply cable car
existing WWTP [type, condition, volume l/PE]	14-chambers, good condition, 140

 

Fig. 4.1: 2-lines primary treatment of the WWTP Berlin Refuge consists of 6 septic tank and 2 pumping- and equilisation tanks.

Fig. 4.2: Flow-scheme of the WWTP Berlin Refuge (all 18 tanks of  the existing former sludge system have been reused)

 

Fig. 4.3: Activated sludge sample of the Biocos-plant: The sludge shows sufficient flocculation and settling properties.

Design and treatment efficiency

Loading of biological treatment

WWTP Berlin Refuge	seasonal average	max. week	max. day
loading [PE40]	96	208	260
BOD5-load  [kg/d]	3.8	8.6	10.7
influent flow Q [m3/d]	7	14	18

 

Design according to the F/M ratio in the max. week

V aerob = 4 x 2 m2 x 1.2 m = 9.6 m3 (volume B-tank)

Maerob = 9.6 m 3 x 4 kg SS/m3 = 38.4 kg SS (aerobic sludge mass)

BSS = 8.6 kg BOD 5/d : 38.4 kg SS = 0.22 kg/kg.d (aerobic sludge loading)

OB = 8.6 x 3 kg O2 /kg BOD5 : 24 h = 1.1 kg O2/h (oxygen demand)

Energy demand

max. power [W]	max. electric work [kWh/d]	mean electric work [kWh/d]
700	12.5	12.5

Treatment efficiencies

date [dd.mm.yyyy]	CODeffluent [mg/l]	NH4-N effluent [mg/l]	NO3-N effluent [mg/l]	CODelimination [%]	Nelimination [%]	loading [% of PE max]
24.8.1999	65	66	0.7	94	1
25.6.2000	55	26	6.8	96	50	40
19.7.2001	125	2	12.3	87	77	70

back