Presentacion Rotary Drum Composting of Mixed Organic

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


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


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


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


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


Nitr

ogen

(%)

0

0.2

0.4

0.6

0.8

1

Inor

gani

c-N

(%)


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


Nitr

ogen

(%)

0

0.2

0.4

0.6

0.8

1

Inor

gani

c-N

(%)


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


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


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


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


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


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%



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

Documents

Presentacion Rotary Drum Composting of Mixed Organic