presentacion rotary drum composting of mixed organic
TRANSCRIPT
ROTARY DRUM COMPOSTING OF MIXED ORGANIC WASTE BASED ON
DIFFERENT C/N RATIOS
By
AJAY S. KALAMDHADDEPARTMENT OF CIVIL ENGINEERING
INDIAN INSTITUTE OF TECHNOLOGY, ROORKEEROORKEE – 247667 (INDIA)
SOLID WASTE MANAGEMENT SYSTEM(INDIA)
WASTE GENERATION
TEMPORARY STORAGE
PRIMARY COLLECTION
SECONDARY COLLECTION
TRANSPORTATION
PROCESSING & RECOVERY
DISPOSAL
Costly processes
40-50% Organic fractionDECENTRALIZED
COMPOSTING
ROTARY DRUM COMPOSTING
CompostCompostRotary Drum Rotary Drum ComposterComposter
Waste Segregation & ShreddingWaste Segregation & Shredding
Organic WasteOrganic Waste
One of the promising decentralized composting technology.Excellent composting concept for smaller communities or in projects that require a rapid and enclosed pathogen kill process.
Short composting period
Temperature reaches up to 65-70oC
No Odor problem
Ease in Operation
Yield uniform marketable compost
Environment Friendly
No Leaching or Spillage
Less Space requirement
ADVANTAGES OF ROTARY DRUM
ROTARY DRUM
FUNCTION OF ROTARY DRUM
The tumbling action of the drum mixes, agitates and moves the material.
Rotation expose the material to air, add oxygen and release heat and gaseous products.
Maintain favorable environmental conditions.
Aerobic microbes flourished and work more quickly to breakdown the waste.
FACTORS AFFECTING COMPOST QUALITY
Low degradation rate
HIGHER
LOWERNitrogen lossC/N RATIO
Initial moisture content
Temperature
AerationIngredients & Proportion
Test the performance of the Rotary drum for biodegradation
of various types of organic wastes on different C/N ratio.
1) C/N = 15
2) C/N = 22
3) C/N = 30
OBJECTIVES OF THE STUDY
METHODOLOGY
Waste Selection & Collection
Shredding
Waste Combinations based on C/N ratios
Rotary Drum Composting
Operation of Composting Process
Compost
Cow dung, Food waste, Vegetable
waste, paper waste, Saw dust
Particle size < 2 cm
Quality check
Volume 250 L, Manual turning
24 h turning, No water addition
C/N = 15C/N = 22C/N = 30
RESULTS & DISCUSSIONTEMPERATURE
0
1020
3040
50
6070
80
1 2 3 4 5 6 7 8 9 10 11 12 13
Time of composting (Days)
Tem
pera
ture
(o C)
C/N=15C/N=22C/N=30Ambient
C/N=15 observed 70oC (maximum in all three) and longer thermophilic phase (6 days) due to higher amount of grass cutting.C/N=30 required 5 days, a comparative longer time, to reach a maximum temperature of only 50oC less than C/N=15 and 22.
MOISTURE CONTENT
01020304050607080
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
Moi
stur
e co
nten
t (%
)
C/N=15C/N=22C/N=30
C/N=15 observed the higher initial moisture content of 68% due to the higher content of grass cutting and food waste.Lower final moisture content observed in C/N=22 (44%) indicatesthe lower microbial activities.
pH
0123456789
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
pH
C/N=15C/N=22C/N=30
pH is lower (6.25) at the beginning of C/N=30 than C/N=15 and 30 due to larger amount of food and vegetable waste.The decrease in pH at the later stage of composting was caused by the volatilization of ammonical nitrogen.
0
10
20
30
40
50
60
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
TO
C (%
)
C/N=15C/N=22C/N=30
Total Organic Carbon (TOC)
Lower final TOC observed in C/N=22.Around 30% of the available carbon in C/N=15 and C/N=30 were utilized by micro-organism as a source of energy as compare to 22% in C/N=22.
TOTAL PHOSPHORUS
0
1
2
3
4
5
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
Tot
al P
hosp
horu
s (g/
kg)
C/N=15C/N=22C/N=30
The higher initial total P (organic and inorganic) in C/N=15 observed than C/N=22 and 30 due to the higher content of grass cutting.Increase in total P (organic and inorganic) in C/N=22 and 30 depicted 30% compared to 19% in C/N=15.
NITROGEN DYNAMICS
00.5
11.5
22.5
33.5
1 3 5 8 10 12 15 17 20Time of composting (Days)
Nitr
ogen
(%)
0
0.2
0.4
0.6
0.8
1
Inor
gani
c-N
(%)
Total Nitrogen Organic nitrogen Ammonium Nitrate
C/N=15
C/N=15 observed 15% loss of NT due to the low C/N ratio. Nitrogen may be lost by the escape of ammonia or other volatilenitrogenous gases from the composting material to the atmosphere.
C/N=22
0
0.5
1
1.5
2
2.5
1 3 5 8 10 12 15 17 20Time of composting (Days)
Nitr
ogen
(%)
0
0.2
0.4
0.6
0.8
1
Inor
gani
c-N
(%)
Total Nitrogen Organic nitrogen Ammonium Nitrate
The Norg decreased due to the ammonification of Norg to NH4-N by the fourth day in C/N=22.
A further increase in the Norg in C/N=22 can be attributed as a consequence of strong degradation of organic carbon compounds.
C/N=30
0
1
2
3
4
5
1 3 5 8 10 12 15 17 20Time of composting (Days)
Nitr
ogen
(%)
0
0.2
0.4
0.6
0.8
1
Inor
gani
c-N
(%)
Total Nitrogen Organic nitrogen Ammonium Nitrate
C/N=30 contained significantly higher NT (4.34%) throughout composting because of the higher amount of food/vegetable waste used in the experiment.
COLIFORMSC/N=15
1.00E+00
1.00E+02
1.00E+04
1.00E+06
1.00E+08
1.00E+10
1.00E+12
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
Bac
teri
a/g
Total coliformFecal coliformFecal streptococci
The more decrease in total coliform achieved in C/N=15 in the initial one week of composting due to the higher temperature(70oC) as compared to the C/N=22 and 30.
C/N=22
The percentage reduction of fecal coliforms and fecal streptococci in C/N=15 and 22 are higher comparing to C/N=30.
1.00E+00
1.00E+02
1.00E+04
1.00E+06
1.00E+08
1.00E+10
0 2 4 6 8 10 12 14 16 18 20Time of composting (Days)
Bac
teria
/g
Total coliformFecal coliformFecal strptococci
C/N=30
1.00E+00
1.00E+02
1.00E+04
1.00E+06
1.00E+08
1.00E+10
1.00E+12
0 2 4 6 8 10 12 14 16 18 20
Time of composting (Days)
Bac
teri
a/g
Total coliformFecal coliformFecal streptococci
C/N=30 observed 2.5 × 105 fecal coliforms and 2.1 × 104 fecal streptococci higher comparing to C/N=15 and 22.
BOD & CODC/N=15
0100200300400500600700800900
1 3 5 8 10 13 15 17 20Time of composting (Days)
Bio
dgra
dabl
e or
gani
cm
atte
r (m
g/l)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
BO
D/C
OD
rat
io
BODCODBOD/COD
C/N=22
0200400600800
1000120014001600
1 3 5 8 10 12 15 17 19 22
Time of composting (Days)
Bio
logi
cal o
rgan
ic m
atte
r(m
g/l)
0
0.2
0.4
0.6
0.8
1
BO
D/C
OD
rat
io
BODCODBOD/COD
C/N=30
0
200
400
600
800
1000
1 3 5 8 10 13 15 17 20Time of composting (Days)
Bio
dgra
dabl
e or
gani
cm
atte
r (m
g/l)
0
0.2
0.4
0.6
0.8
1
BO
D/C
OD
rat
io
BODCODBOD/COD
POINTS OF DISCUSSION Total Nitrogen = 2.1%Total Phosphorus = 3.5%NH4-N = 0.036%TOC = 24.82%Fecal Coliform = 7.5 × 102
Fecal Streptococci = 2.3 × 103
BOD/COD ratio = 0.23Total Nitrogen = 4.35% Total Phosphorus = 2.42%NH4-N = 0.21%TOC = 35.3%Fecal Coliform = 2.5 x 105
Fecal Streptococci = 2.1 × 104
BOD/COD ratio = 0.6Total Nitrogen = 2.08%Total Phosphorus = 4.62%NH4-N = 0.37%TOC = 18.72%Fecal Coliform = NilFecal Streptococci = 2.1 × 102
BOD/COD ratio = 0.41
C/N = 22
C/N = 30
C/N = 15
Max. Temp. = 50oCMoisture = 56%
Max. Temp. = 60oCMoisture = 44%
Max. Temp. = 70oCMoisture = 54%
CONCLUSIONS
Rotary Drum composting of mixed organic waste atinitial C/N ratio of 22 resulted in the compost reaching maturity after 20 days of composting.
While initial C/N ratio of 30 can produce quality compost, but it would require a composting period of more than 20 days.
Consequently, loss of nitrogen observed at low C/N ratio of 15, which is not suitable for composting in Rotary drum.
EXTENDED WORK (Dr. A. A. Kazmi and Ajay S. Kalamdhad)(Financially supported by DST, Govt. of India)
0015Grass cutting
64.93
29.61
69
5
10
4
10
25
18
Run C
61.1268.04Moisture content (%)
21.7715.2C/N ratio (Kg)
6045Initial weight (Kg)
55Manure (Kg)
100Saw dust (Kg)
00Paper waste (Kg)
2015Vegetable waste (Uncooked) (Kg)
010Food waste (Cooked) (Kg)
250Cattle manure (Kg)
Run BRun AIngredients/ Initial characteristics
Parameter analyzed
Temperature
Moisture content
pH
TOC
Total Phosphorus
Nitrogen Dynamics (NT, Norg, NH4+, NO3
-)
Coliforms (Total, Fecal & Fecal Streptococci)
BOD & COD