In general, the client is required to provide
a roofed plant room with the size of 2 m x
3m x 3m (H) for fitting 5m3/day or 10m3/day
bio-toilet. The plant room should have power
supply, water drain, a water tap for water
supply and air ventilation system.
The treatment of bio-toilet is based on the
membrane bio-reactor technology. It comprises
the biological treatment and membrane separation
in a single reactor. The biological treatment
uses the carbonaceous bacteria to decompose
the organic pollutants in incoming wastewater.
With the application of membrane separation,
the treated wastewater could be separated
from bacteria and suspended solids so that
the crystal clear effluent could be obtained
and the clarification tank for treated effluent
could be omitted. Disinfection is being done
by ultraviolet (UV) or chlorination.
biological treatment being used is very similar
to traditional activated sludge process commonly
used in sewerage treatment plants in Hong
Kong operates by Drainage Services Department
(DSD). The treatment does not generate any
hazardous or explosive gas. Since the digestion
process is very effective and mainly undergoes
in aerobic environment, the odour issue is
Dunwell bio-toilets adopt the membrane bio-reactor (MBR) technology to treat the wastewater. Since the membrane (pore size < 0.1 micron) is submerged inside the biological reactor,
all carbonaceous bacteria for decomposing
organic pollutants can be retained inside
the reactor. Comparing the bacteria content
with the traditional biological reactor such
as oxidation ditch/ Rotating Biological Contactor,
RBC, MBR has 3-4 times higher of bacteria
content. The higher the bacteria content,
the higher efficiency of the biological reactor.
It also results of smaller footprint for the
bio-reactor. With the membrane separation,
the crystal clear treated effluent can be
obtained and it could be re-used as the water
for irrigation, floor washing and toilet flushing.
Yes. The feed tank could have 2 hours retention time for peak flow. For example, if the peak wastewater flow is 2m3/hr., then the feed tank should have the minimum wet volume of 4m3. It should be an underground feed tank.
The client is required to have a technician
to monitor and maintain the system although
the system is fully automatic. Less than an
hour of daily checking is enough to make sure
that all pumps are in good operating conditions.