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

back

Coburg Refuge

Site description and boundary conditions
Design and treatment efficiency

Site description and boundary conditions

boundary conditions
maximum daily organic load [PE]	180
maximum hydraulic load [m3/d]	6.4
annual organic load [kg BOD/a]	330
altitude [m a.s.l.]	1970
sensitivity [hydrogeology, protected area ...]	well, limestone
lagal requirements [BOD elimination]	90 %
operation period [season]	summer
energy supply [type, kW]	Photovoltaic, 0.3; Aggregate, 17
means of transport [type]	supply cable car
existing WWTP [type, condition, volume l/PE]	grease trap, 2-chambers, poor condition

   
 

Fig. 4.8: Flow scheme of the WWTP Coburg Refuge

 

Fig. 4.9: Discharge equipment: Compressed air is fed to the syphon (gray pipe), which pumps supernatant water to the sampling tank (orange) and further to the outflow.

 

Fig. 4.10: Set of batteries in the background and charger and inverter in front.

Design and treatment efficiency

Loading of the biological treatment

 

WWTP Coburg Refuge	seasonal average	max. week	max. day
loading [PE40]	40	80	180
BOD 5-load [kg/d]	1.6	3.2	7.2
influent flow Q [m3/d]	3.4	5.0	7.5

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

V_aerob = 3.0 x 1.5 x 2.3 m = 10.35 m³ (volumen B-tank)

M_aerob = 10.35 m³ x 3.6 kg SS/m³ * 3.7 = 26 kg SS (aerobic sludge mass)

B_TS = 3.2 kg BOD₅/d : 26 kg SS = 0.12 kg/kg.d (aerobic sludge loading)

O_B = 3.2 x 3 kg O₂/kg BOD₅ : 24 h = 0.4 kg O₂ /h (oxygen demand)
 
 

Energy demand
 

max. power [W]	max. electric work [kWh/d]	mean electric work [kWh/d]
1200	18.7	18.7

 
Treatment efficiency

date [dd.mm.yyyy]	CODeffluent [mg/l]	NH4-Neffluent [mg/l]	NO3-Neffluent [mg/l]	CODelimination [%]	Nelimination [%]	loading [% v. PWmax]
29.07.1999	315	72	4	81	37	--
08.09.2000	70	41	1	94	74	37
21.07.2001	55	7	16	92	62	43

back