Comparative Point

Hans BioShaft

Process

Attach growth process

Activated sludge
process

Separation process

Capital Investment

Competitive

Standard

Not competitive

Cost & Efficiency

Low (very simple with
high efficiency )

High

Very high

Required Area for
Sewage Treatment Plant

Less than others (less
aeration area, less
sedimentation area , less sludge treatment
required)

Large

Large

Sludge Treatment

Minimal Required

Required

Required

Energy Consumption

Low (only air pumps),
0.004-0.006 KW-hr/gal
(1-1.6KW-hr/m3)

High (air pumps and
large number of
mechanical motors
required), 0.011-0.015
KW-hr/gal (3-4 KWhr/
m3)

Very high (air pumps and large number of mechanical motors required) - up to 0.026 KW-hr/gal
(7 KW-h/m3), ref Stefan Geizler, Aachen University Chemical Engineering Institute

Maintenance &
Cleaning Process
(Chemicals)

Maintenance free self
cleaning process

Maintenance needed -
sludge removal and
chemical treatment of
sludge.

Intensive maintenance and
chemicals required for flushing and cleaning membranes

Replacement of Major Items

No replacement

Replacement of
electromechanical
parts (ie. sludge
pumps, recycling pumps, gears, etc)

Membrane replacement periodically

Possibility of Expansion

Unlimited

Limited

Limited

Operating Cost

Low (air compressor only, no electromechanical
equipment, low number of personnel required)

High (air pumps and large number of mechanical motors required, large number of personnel required)

High (air pumps and large number of mechanical motors required, large number of personnel required)

Maintenance

Very low (no mechanical equipment only standard compressor)

High

High

Construction
Possibilities

Above and underground

Above ground and
some of them can be
erected under ground
(with limited capacity)

Some of them can be erected under ground (with limit capacity)

Relocation of the
Sewage Treatment
Plant

Possible

Not possible

Not possible

Population Limit

No limits

No limits

No limits

Landscape Disturbance

Low

High

High

Odor

Negligible

Present

Low

Water Effluent Quality
(BOD/TSS)

Tertiary 10/10ppm
(10/10 mg/l)

Secondary - requires
filtration to reach
tertiary quality 30/30
ppm (30/30 mg/l)

High quality 5/5 ppm (5/5 mg/l)