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

back

Darmstadt Refuge

Site description and boundary conditions
Design and treatment efficiency

Site description and boundary conditions

boundary conditions
maximum daily organic load [PE]	75
maximum hydraulic load [m3/d]	5.3
annual organic load [kg BOD/a]	220
altitude [m a.s.l.]	2384
sensitivity [hydrogeology, protected area ...]	granite
lagal requirements [BOD elimination]	40 %
operation period [season]	summer
energy supply [type, kW]	water power plant, 12
means of transport [type]	4WD
existing WWTP [type, condition, volume l/PE]	3-chambers, poor condition, 93

   
 

Fig. 4.11: Flow scheme of the WWTP Darmstadt Refuge

   

Fig. 4.12: View of the building with the filterbag system and with the Darmstadt Refuge in the background.

 

Fig. 4.13: One of the two filterbag lines.

Design and treatment efficiency

Loading
 

WWTP Darmstadt Refuge	seasonal average	max. week	max. day
loading [PE60]	40	65	75
BOD 5-load [kg/d]	2.4	3.9	4.5
influent flow Q [m3/d]	2.9	4.6	5.3

 

Design of the composting process Mtotal, wet = 3.700 l (g) / PE60 x 0,15 l (kg) / PE60 = ca. 555 l (kg)/a (wet filterbag sludge) ca. 45 l (kg) per filterbag wet: ca. 12 filterbags / year required

Energy demand
 

No energy demand !

 

Treatment efficiency
 

date [dd.mm.yyyy]	CODeffluent [mg/l]	NH4 -Neffluent [mg/l]	NO3 -Neffluent [mg/l]	CODelimination [%]	Nelimination [%]	load [% v. PEmax ]
11./12.08.2000	900	44	1.4	41	10	52

Elimination efficiencies have been calculated from a 3 weeks mass balance. The dry matter content increased from 6 to 14 % to about 18 % during the winter. In other words the weight of the filterbags decreased to half the volume during the period without loading.

back