BIO DIGESTOR TOILET
Why bio-toilet system is needed
- Need for environment friendly toilet.
- Unacceptable hygiene conditions
particularly at railway stations.
- Preventing damages to tracks by way of
corrosions.
- Likeable sights at stations.
- Environmental friendliness.
- Eliminating manual scavenging.
- Reduction in consumption of water.
- Providing better working environment to
track and other maintenance staff.
- Because india has very big railway
network, so its very necessary to
keep the railway tracks neat and
clean, to provide the healthy,oderless
and non-obnoxious travelling
conditions
- Stainless steel bio digestor is mainly
used in railway coaches.
- Mohan rail components company is
the main supplier of this stainless
steel
Aerobic Bio Toilet System
- Tried bio digester imported from M/S
Microphor, USA.
- Aerobic bacteria used for decomposing
waste into gases and water.
- Liquid is discharged on the ground after
chlorination.
- This system has been successful but
periodic replenishment and high initial
as well as maintenance cost are the
stumbling block.
Limitations of aerobic bio toilet
system
- Foul smell.
- Lack of non bio-degradable sepration
system.
- Choking due to accommodation of non
- bio-degradable materials.
Due to all above limitations anaerobic
bio- toilets are preffered above aerobic
bio-toilets now a days by indian
railways
.
Bio Digester Toilet-It is a innovative
techno-logy for disposal of human
waste in ecofriendly manner.
-These bio-toilets can function at any
temperature between 55 to 60 degree
c.
-In this technology anaerobic bacteria
is used for decomposition
Anaerobic bacteria- Developed by
DRDE.
-Doubles its population in 6 to 8 years.
-Dominates and de-composes matter
into liquid and gases.
-These bacteria once charged does not
require replenishment for long time
and system is maintenance free.
-Can withstand sub zero temperature
and 70 degree centigrade.
-Cold temperature does not effect the
inside working.
- Complete elimination of pathogens.
- Economically viable.
- No dependence on limited and costly
conventional energy resources.
- Can be installed and made operational
in 12 hours.
- No need to connect to sewage line,
septic tank.
- Routine use chemicals like phenyl,
kerosene etc do not harm bio toilets.
Working principle of bio-digester
system
An inoculum with the help of anaerobic
bacteria culture is prepared in a bacteria
culture generation plant. Initially 100 litres
is charged in each toilet. The capability of
reproduction of bacteria itself makes the
tank maintenance free. However one time
charging of toilet tank is enough till next
POH of the coach.
Anaerobic bio-digester system working
Anaerobic bio digester system-
Digester
Steps in anaerobic bacteria.
- Large polymers are converted into
simpler monomers.
- Simple monomers are converted into
non-volatile fatty acids.
- Volatile fatty acids are converted into
acetic acid (CO2 & H2).
- Acetate and H2 are converted into
methane and carbon dioxide.
Anaerobic bio digester system
-Bio gases and parameters monitored
Compound Chemical Name %
Methane CH 4 50–75
Carbon dioxide CO2 25–50
Nitrogen N2 0–10
Hydrogen H2 0–1
Hydrogen sulphide H 2S 0–3
Parameter Recommended Values
pH 6 to 9
Total Solids Max 750mg/100ml
Total Dissolved solids Max 350mg/100ml
COD levels Max 2000 ppm
Construction of bio toilet tank
- Bio toilet tank is made of stainless steel
of grade AISI 316&304.
- It consists of seven chambers, as shown in
figure below.
- Chamber 1 is partitioned with steel net
called as solid-liquid separator.
- In turn chamber 2,3,4,5,6 and 7 are
prepared to allow the bio-degradation of
human waste.
Cont….
- All partitions are fixed with mats on
both sides, with the help of these mats
the anaerobic bacteria are set.
- On the outside wall of the tank a
chlorination chamber is fitted, to
dispose of chlorinated water, this
chamber is filled with chlorine tablets,
which chlorinates the bio-degraded
liquid.
- This liquid is non-hazardous and
environmental friendly.
Working of anaerobic bio digester
- Seven chambers in a tank.
- First chamber has grill partition so that
bio-degradable objects do not pass to
further chambers.
- Fecal matter in slurry form goes from
first chamber to second chamber
through a pipe (from bottom pf first
chamber).
- Slurry flows from second chamber to
sixth chamber through slits in the
partition.
- From sixth chamber to seventh
chamber it flows through a pipe (from
bottom of the sixth chamber).
- From seventh chamber to chlorinator it
flows through a pipe ( from top of the
seventh chamber).
- Finally chlorinated water discharged to
the ground.
- Nylon matting is provided on all walls
for colonization of bacteria.
- In case of choking valve has to be open.
Improvement areas in anaerobic
toilets.
- Frequent choking of the toilets.
- Lack of awareness among passengers.
- Lack of dustbin inside the toilet for non
bio degradable materials.
- Lack of identification of enviro-
nmentally friendly coaches.
- Lack of awareness among staff.
Performance results
- Based on the trial runs performed on
various trains, the results which are
witnessed by the railway users are-
- The bacteria are total effective and
almost complete degradation of fecal
matter inside the tank is being held.
- Only water is being discharged and no
fecal matter is discharged.
- No perceptible foul smell was noticed in
bio-toilet laboratries.
Thank you
