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

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Höllentalanger Refuge

Site description and boundary conditions
Disign and treatment efficiency

Site description and boundary conditions

 

boundary conditions
maximum daily organic load [PE]	216
maximum hydraulic load [m3/d]	10
annual organic load [kg BOD/a]	700
altitude [m a.s.l.]	1379
sensitivity [hydrogeology, protected area ...]	nature reserve, lime
lagal requirements [BOD elimination]	< 40 mg/l
operation period [season]	summer
energy supply [type, kW]	aggregate, 32 / 45
means of transport [type]	supply cable car
existing WWTP [type, condition, volume l/PE]	3-chambers, good condition, 140

 

Fig. 4.20: On the left hand side a tank of the existing treatment system, on the right hand side the new high-grade steel SU-tank transported by a helicopter.

 
 

Fig. 4.21: Flow-scheme of the WWTP Höllentalanger Refuge

Fig. 4.22: Helicopter transport of the 2 sludge drying beds (high-grade steel box set into a concrete frame)

Design and treatment efficiency

Loadind of the biological treatment
 

WWTP Höllentalanger Refuge	seasonal average	max. week	max. day
loading [PE40]	84	165	216
BOD 5-load [kg/d]	3.36	6.6	8.64
influent flow Q [m3/d]	4.1	8.7	10

 

Bemessung according to the F/M ration in the max. week

V_aerob = 12 m³ (volume B-tank)

M_aerob = 12 m³ x 5 kg SS/m³ = 60 kg SS (aerobic sludge mass)

B_SS = 6.6 kg BOD₅ /d / 60 kg SS = 0.11 kg/kg.d (aerobic sludge loading)

O_B = 6.6 x 3 kg O₂/kg BSB₅ : 16 h = 1.24 kg O₂ /h (oxygen demand)
 
 

Energy demand
 

max. power [W]	max. electric work [kWh/d]	mean electric work [kWh/d]
3000	48	48

 

Treatment efficiency
 

date [dd.mm.yyyy]	CODeffluent [mg/l]	NH4 -Neffluent [mg/l]	NO3 -Neffluent [mg/l]	CSBelimination [%]	Nelimination [%]	loading [% of PEmax ]
22.09.2000	155	70	21	89	71	-
09.08.2001	165	4	2.6	81	96	71

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