5 Case 5: Bioreactor Co-composting of Sewage Sludge and Restaurant Waste

Biotreatment of Sludge and Reuse



187



Fig. 5.9. Section view of 200 L – bioreactor composter (41).



The first phase of the co-composting process, known as the fermentation phase of sewage

sludge and restaurant waste, was performed in a 200-L bioreactor (Fig. 5.9). Shredded garden

waste was added as bulking agent. A 2:1 (wt/wt) ratio of municipal solid waste and sewage

sludge was found to give the best initial C/N ratio for the composting process. The second

phase of composting process was performed in an open space using a windrow system (heap

method). The produced compost was characterized and the results were almost identical to

commercial compost and also complied with US EPA standards (41).

A growth study using produced compost to grow spinach showed satisfactory results. The

ratio of the compost to the soil was 2:1 based on a volume basis. It was found that the

growth of spinach using compost produced from the oxidation pond and activated sewage

sludge was almost identical to that of commercial compost (Fig. 5.10). The spinach that

grew in the activated sewage sludge compost product produced more greenish color in the

leaves (36).



NOMENCLATURE

C = carbon

Ca = calcium

CC = commercial compost

Cd = cadmium

cfu = colony forming units (coliform count)

cm = centimeter

CO2 = carbon dioxide

Cr = chromium



188



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A



B



C



D



A-Activated sludge compost

B-Septic tank compost

C-Oxidation pond compost

D-Commercial compost

E-No compost



E

Fig. 5.10. Growth studies with spinach using sewage sludge composts (35).



Cu = copper

D = diameter

EFB = empty fruit bunch

EM = effective microorganism

EU = european union

Fe = iron

FFSC = food factory sludge compost

g = gram

H2 O = water

K = potassium

LSB = liquid state bioconversion

LSC = leachate sludge compost

mm = millimeter

Mn = manganese

N = nitrogen

NH3 = ammonia

NH4 OH = ammonium hydroxide

Ni = nickel

O2 = oxygen

◦C = degree celsius

P = phosphorus



Biotreatment of Sludge and Reuse



189



Pb = lead

POME = palm oil mill effluent

ppm = parts per million

PSC = palm oil mill sludge compost

SSB = solid state bioconversion

SSC = sewage sludge compost

USA = United States of America

US EPA = Unites States environmental protection agency

Zn = zinc



REFERENCES

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during aerobic composting. J Hazard Mater 142:216–221

2. Haug RT (1980) Compost engineering principle and practice. Ann Arbor Publisher, Inc, Michigan

3. Haug RT (1993) The practical handbook of compost engineering. Lewis Publishers, Boca Raton,

F1.717 pp

4. Hughes EG (1980) The composting of municipal wastes. In: Berwick MM (ed) Handbook of

organic wastes conversion, Van Nostrand Reinhold, New York

5. Bertoldi M, Vallini G, Pera A, Zucconi F (1985) Technological aspects of composting including

modeling and microbiology. In: Gesser JKR (ed) Composting of agricultural and other wastes,

Elsevier Applied Science Publishers, London, p 320

6. Biddlestone AJ, Gray KR, Day CA (1987) Composting and straw decomposition. In: Forster

CF, John Wase DA (eds) Environmental biotechnology, Ellis Horwood Limited, Chichester,

pp 137–175

7. Diaz LF, Savage GM, Eggerth LL, Golueke CG (1993) Composting and recycling – municipal

solid waste, vol 1. Lewis Publishers, Boca Raton, USA

8. Gaur AC (1982) Role of mesophilic fungi in composting. Agr Wastes 4(6):453–468

9. Mitchell DA, Lonsane BK (1993) Definition, characteristics and potential. In: Doelle HW, Rolz C

(eds) Solid substrate cultivation, Elsevier Applied Science, London, pp 1–13

10. Renner R (2000) Sewage sludge – pros and cons. Environ Sci Technol 34:1–9

11. Lee CJ, Spinosa L, Liu JC (2002) Towards sustainable sludge management. Water 21:22–23

12. Hettenbach T, Cohen B, Wiles R, Cook K (1998) Dumping sewage sludge on organic farms? why

USDA should just say No. EWG policy analysis. Environmental Working Group, April 30, 1998

13. US EPA (1995) Process design manual: land application of sewage sludge and domestic septage,

EPA/625/K-95/001, Washington, DC

14. Stan V, Virsta A, Dusa EM., Glavan AM (2009) Waste recycling and compost benefits. Notulae

Botanicae Horti Agrobotanici Cluj-Napoca 37(2):9–13

15. Biddlestone AJ, Ball D, Gray KR (1981) Composting and urban waste recycling. Academic Press,

Inc. Publisher, New York, pp 125–128

16. Crawford DL (1986) The role of actinomycetes in the decomposition of lignocellulose. FEMS

Symps 34:715–728

17. Gotaas HB (1956) Composting – sanitary disposal and reclamation of organic wastes. WHO,

Geneva

18. Golueke CG (1977) Biological reclamation of solid wastes. Rodale Press, Emmau, USA, p 249



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19. Verdonck O (1998) Compost from organic waste materials as substitute for the usual horticultural

substrate. Biol Waste 26:325–330

20. Gaur AC (1987) Recycling of organic wastes by improved techniques of composting and other

methods. Resour Conserv 13:157–174

21. Hassan MA, Idris A, Ariff A, Abdul Karim MI, Abdul Razak AR, Baharum Z (2001). Cocomposting of sewage sludges and municipal solid wastes. Research on sludge. Final report. Indah

Water Konsortium and Universiti Putra Malaysia

22. Obeng LA, Wright FW (1987) Integrated resource recovery the co-composting of domestic solid

and human wastes. World bank technical paper number 57. The World Bank, Washington, DC,

pp 1–91

23. Cannel E, Moo-Young M (1980). Solids state fermentation systems. Process Biochem 15:24–28

24. Mudgett RE (1986) Solid-state fermentations. In: Demain AL, Solomon HA (eds) Manual of

industrial microbiology and biotechnology, American Society for Microbiology, Washington, DC,

pp 66–83

25. Kargi K, Curme JA (1985) Solid fermentation of sweet sorghum to ethanol in a rotary drum

fermentor. Biotechnol Bioeng 27:1122–1125

26. Laukevics JJ, Apsote AF, Viesturs UE, Tangerdy RP (1984) Solid substrate fermentation of wheat

straw to fungal potien. Biotechnol Bioeng 26:1465–1474

27. Grajec W (1987) Production of D-xylanases by thermophilic fungi using different methods of

culture. Biotechnol Lett 9:353–356

28. Bajracharya R, Mudget RE (1980) Effect on control gas environment in solid substrate fermentations of rice. Biotechnol Bioeng 22:2219–2235

29. Kumar PKR, Lonsane BK (1987) Gibberellic acid by solid state fermentation: consistent and

improved yields. Biotechnol Bioeng 30:267–271

30. Mitchell DA, Greenfield PE, Doelle HW (1988) Development of a model solid state fermentation

system. Biotechnol Tech 2:1–6

31. Hasseltine CW (1972) Biotechnology report. Solid state fermentations. Biotechnol Bioeng 14:

517–532

32. Biddlestone AJ, Gray KR (1985) Composting. In: Young MM (ed) Comprehensive biotechnology,

vol 4. Pergamon Press, New York, pp 1059–1070

33. Moo-Young M, Moreira RA, Tangerdy RP (1983) Principles of solid substrate fermentation. In:

Smith JE, Berry DR, Kristiansen B, Arnold E (eds) The filamentous fungi, vol 4. Edward Arnold,

London, pp 177–144

34. Viesturs UE, Apsite AF, Leukevics JJ, Ose VP, Bekers MJ, Tangerdy RP (1981) Solid-state fermentation of wheat straw with Chaetomium cellulolyticum and Trichoderma lignorum. Biotechnol

Bioeng Symp 11:359–369

35. Tangerdy RP, Murphy VG, Wissler MD (1983) Solid-state fermentation of cellulosic residues. Ann

N Y Acad Sci 413:469–472

36. Abdullah AL, Tangerdy RP, Murphy VG (1985) Optimization of solid substrate fermentation of

wheat straw. Biotechnol Bioeng 27:20–27

37. IWK-UPM (2002) Utilization of sewage sludge as fertilizer and as potting media. Report on Project

1, Indah Water Konsortium – Universiti Putra Malaysia, May 2002, Malaysia

38. Food Act and Regulations (1985) MDC Publishers Printers Sdn, Kuala Lumpur, pp 192–193

39. Kabbashi NA (2002) Study of culture condition for solid state fermentation of sewage treatment

plant sludge to compost. Doctor of Philosophy Thesis, Faculty of Engineering, Universiti Putra

Malaysia, Serdang, Malaysia



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40. Hassan AHH (2001) Solid state bioconversion of oil palm empty fruit brunches (EFB) into compost

by selected microbes, Master of Science Thesis, Faculty of Engineering, Universiti Putra Malaysia,

Serdang, Malaysia

41. Zainal BB (2002) Composting of selected organic sludges using rotary drum in comparison to

windrow system, Master of Science Thesis, Faculty of Food Science and Biotechnology, Universiti

Putra Malaysia, Serdang, Malaysia

42. Abdul Rahman AR (2004) Bioreactor co-composting of sewage sludge and restaurant waste.

Master of Science Thesis, Faculty of Food Science and Biotechnology, Universiti Putra Malaysia,

Serdang, Malaysia

43. Wang LK, Shammas NK, Hung YT (eds) (2009) Advanced Biological Treatment Processes.

Humana Press, Totowa, NJ, 737 pp

44. Wang LK, Ivanov V, Tay JH, Hung YT (eds) (2010) Environmental Biotechnology. Humana Press,

Totowa, NJ, 975 pp



6

Kitchen Refuse Fermentation

Mohd Ali Hassan, Shahrakbah Yacob, Cheong Weng Chung,

Yoshihito Shirai, and Yung-Tse Hung

CONTENTS

I NTRODUCTION

F ERMENTATION OF K ITCHEN R EFUSE

P RODUCTION OF M ETHANE

P RODUCTION OF O RGANIC ACIDS

P RODUCTION OF L -L ACTIC ACID

P OTENTIAL A PPLICATIONS OF K ITCHEN R EFUSE F ERMENTATION

P RODUCTS

I NTEGRATED Z ERO D ISCHARGE C ONCEPTS OF M UNICIPAL SOLID

WASTE M ANAGEMENT AND H ANDLING

R EFERENCES

Abstract Controlled fermentation has been used for kitchen waste treatment. The most

important factors affecting methane production from kitchen waste is organic loading rate and

hydraulic detention time. Two main types of fermentation of kitchen waste are natural fermentation and controlled fermentation. The fermentation products are poly-3-hydroxyalkanoates

(PHA) and poly-lactate (PLA).



1. INTRODUCTION

In the last century, the world had experienced various industrial revolutions, which were

driven by fossil fuels such as petroleum and coal. These rapid changes also brought along

serious environmental issues such as the dumping of nonbiodegradable polymers in landfills,

uncontrolled release of greenhouse gases, and usage of nonrenewable energy. These concerns

have sparked interest in finding alternative renewable materials such as industrial chemicals

and biodegradable polymers that will reduce the environmental pollution. Despite intensive

research and development in green technology and discussions by interested parties, there was

From: Handbook of Environmental Engineering, Volume 11: Environmental Bioengineering

Edited by: L. K. Wang et al., DOI: 10.1007/978-1-60327-031-1_6 c Springer Science + Business Media, LLC 2010



193



194



M. A. Hassan et al.



no major commitment in adopting green technology at a commercial level. Even though the

world has acknowledged the depletion of fossil fuel reserves and increases in oil production

cost, the price per unit of chemical derived from petroleum is relatively more competitive.

However, this perception is about to change as a result of current biotechnological developments in utilizing biological agents and cheap renewable resources to produce bioproducts.

Biotechnology has made a strong impact by providing a sound alternative technology that

contributes to the well-being of the environment. Biological agents such as enzymes and

cells are more efficient than chemical reagents. Enzymes are known for their specificity and

are extremely efficient in producing intermediates or chemicals and can perform as efficient

as metal catalysts. Live cells can be considered as living catalysts because of their ability

to assimilate or dissimilate chemical compounds while harvesting the energy released. The

abundance of organic matter, particularly the biomass generated by domestic and agricultural

activities, coupled with the biocatalysts mentioned, promises a great potential in producing

competitive chemicals or intermediates for the chemical industries. The production of chemicals that cannot be synthesized chemically such as citric acid, monosodium L-glutamate, and

L-lysine from agricultural residues have encouraged the acceptance of biotechnology as a

future technology by the chemical industry.



1.1. Availability and Potential of Kitchen Refuse Biomass

The potential and definition of municipal solid wastes (MSW) as renewable materials may

vary depending on the economic scale of each country. In developed nations such as Japan

and the United States, MSW consists of paper and paperboard products, yard trimmings, glass,

metals and to some extent electrical appliances as in Fig 6.1 (1, 2) The potential for conversion

of biomass into valuable products is limited because of the low volumetric discharge of

organic matter. Moreover, the organic wastes collected from the municipalities are mostly

being incinerated or converted into compost rather than chemicals. On the other hand, in the

Others

9%

Food

7%



Yard trimmings

16%



Wood

7%



Plastics

9%



Paper-based

37%



Metals

8%

Glass

7%



Fig. 6.1. Materials generated in MSW by weight (3).



Kitchen Refuse Fermentation



195



Table 6.1

Distribution (%) of MSW wet base content in developing countries (3)

Types

Food waste

Grass and

wood

Paper

Textiles

Plastic

Leather and

rubber

Noncombustible



Laos Paraguay Nicaragua Tanzania Philippines Honduras Poland



Turkey



35

25



37

19



34–51

23–26



45

25



45

16



46

12



34–61

2–6



64

2



10

1

6

1



10

1

4

1



5–7

2

4–6

1–2



4

1

2

1



16

4

7

1



12

3

7

2



14–19

3–7

4–8

2



15–18

2–3

6–7

1



23



27



11–23



22



11



18



12–23



7–10



developing nations, the main bulk of MSW will be organic matter. Studies in eight developing

countries have shown that the generation of kitchen refuse from household, restaurant and

commercial venues comprised up to 60% of the total MSW content as shown in Table 6.1 (3).

According to the UN estimates, 60% of the world’s population will be living in urban areas by

the year 2015. It is further estimated that about 90% of the population increase between now

and the year 2015 will be in urban areas. Most of that increase in urban population will be in

developing countries with the MSW generation rate of between 0.5 and 1.3 kg/person/day. In a

recent study by the World Bank, urban waste generation is predicted to increase substantially

over the next years as GNP pre capita increases. It is predicted that a total of 31.6 million

tonnes per day of waste will be generated in the next few years in Asian countries (4) With an

average of 50% of the total MSW being organic-based waste, it is estimated that 15.8 million

tonnes of biomass, a renewable resources, are being disposed daily in Asia alone.

Leachate is one of the immediate products of MSW disposal in the open dumping sites

or landfill. Pollution due to leachate contamination of groundwater system caused by organic

matters, heavy metal and toxic chemicals is inevitable in poorly designed landfills. Leachate

is formed when water percolates through the dumped solid waste, extracting the organic

and inorganic compounds as a result of the natural hydrolytic and fermentative processes.

Generally, such leachates contain high concentrations of soluble and suspended organic and

inorganic matters (5), with significant levels of heavy metals. The biochemical oxygen demand

(BOD) ranges from 20,000 to 50,000 mg/L and tends to vary considerably both daily and

seasonally (6). As shown in Table 6.2, the chemical properties of leachate varies widely

depending on factors such as temperature, water input (rain), composition, and age of MSW.



2. FERMENTATION OF KITCHEN REFUSE

2.1. Natural Fermentation Process

Based on the chemical properties and composition, the most cost-effective method in the

treatment of MSW is using sanitary landfill. By exploiting the low energy requirement of

anaerobic processes, the organic matter which is mainly kitchen refuse is being stabilized.



196



M. A. Hassan et al.

Table 6.2

Characteristics of different leachate sources (6)

Parameters



Fresh leachate



Landfill leachate



pH

BOD5

COD

Total solid

Suspended solid

Ammonium

Total nitrogen

Lactic acid

Acetic acid

Propionic acid

Butyric acid

Phosphorus

Manganese

Zinc

Nickel

Chromium

Copper

Iron

Lead

Cadmium



4.2–5.0

48,000–55,000

65,000–78,000

35,000–52,000

3,870–9,340

200–720

2,000–2,600

13,000–19,000

2,200–5,500

580–3,200

20–1,080

100

7.27

7.72

0.52

0.20

0.44

100

0.45

0.07



7.3–8.7

780–22,440

8,800–40,580

4,600–25,000

1,440–4,670

1,500–2,900

2,200–3,000

50–250

2,230–5,100

120–2,500

130–2,300

Minimal

1.40

5.20

0.70

0.52

0.30

Minimal

0.14

0.01



All parameters are in mg/L except pH.



Alternatively, such organic matter could be easily composted aerobically. Nonetheless, the

potential energy recovery from the anaerobic treatment makes it an advantage over other

methods in the selection of treatment for kitchen refuse. However, the treatment in the sanitary

landfill is far from the optimal conditions, resulting in prolonged existence of organic matter

and environmental problems. Without any process control parameters, the anaerobic treatment

of MSW is largely dependent on the presence of natural occurring microorganisms in the landfill. A few studies have shown that landfill ecosystem harbors a consortium of microorganisms

with diverse biochemical properties forming a complete food chain in stabilizing the organic

matter. Among the reported and identified microorganisms in landfills are Candida spp.,

Bacillus spp., Cellulomonas spp., Staphylococcus spp., Acinetobacter spp., Alcaligenes spp.,

Enterobacter spp., Pasteurella spp., Proteus spp., Pseudomonas spp., Serratia spp., Yersinia

spp., Clostridium spp., Syntrophomonas spp., Lactobacillus spp., Pediococcus spp., Leuconostoc spp., Weisella spp., Desulfuromonas spp., Methanobacterium spp., Methanosaeta spp., and

Methanosarcina spp. (7–11). In addition to the diversification of microbial population in the

landfills, inconsistency of MSW composition, age and poorly designed landfills makes the

treatment of MSW using anaerobic fermentation difficult to control or predict (51, 52).

In general, the anaerobic fermentation of organic matter can be divided into three stages. In

the first stage known as hydrolysis process, all the complex substrates such as carbohydrates,



Kitchen Refuse Fermentation



197



protein, and lipids are being de-polymerized into smaller compounds. The conversions are

controlled by series of extra-cellular enzymes that produce long chain fatty acids and carbon

dioxide. This is followed by the degradation of long chain fatty acids into carbon dioxide,

hydrogen, and short fatty acids such as acetic, propionic, and butyric acids by acid forming

microorganisms (acidogens). As the name implies, this stage is called acidogenesis. The final

stabilization of organic matter will only occur at the final stage of the anaerobic process. At

this point, the methane producing microorganisms (methanogens) which are extremophiles

with narrow optimum growth conditions metabolize the short chain fatty acids mainly

acetic acid to emit methane and carbon dioxide. Another pathway of methane production

is via the reduction of carbon dioxide and hydrogen into methane by the hydrogen-utilizing

methanogens. Methane and carbon dioxide (end-products) will be continuously emitted until

all the organic matter has been depleted.



2.2. Controlled Fermentation

Unlike natural fermentation process that is being carried out in the landfill, controlled

fermentation of kitchen refuse is done with two objectives, firstly to increase the treatment

efficiency and secondly to produce value-added products from the conversion of organic

matters. In general, the organic fraction of MSW will be subjected to properly designed bioreactor, which enables the operators to control the biochemical process toward the production

of desirable products. The types of end products produced from MSW is also affected by

different biochemical processes and microorganisms used. At present, there are two different

biochemical processes that utilize MSW, nonsterile and sterile fermentations. In nonsterile

fermentation, endogenous microorganisms are exploited to produce methane and organic acid

cocktails mainly acetic, propionic, and butyric acids via anaerobic process. The sterile process

is lactic acid fermentation using MSW as raw material using monoculture system.



3. PRODUCTION OF METHANE

Anaerobic degradation of a mixed composition of kitchen refuse such as lipids, carbohydrates, and proteins requires a synergistic relationship between all microbial populations

which occurs only when the optimum conditions for each group of microorganisms exist.

Since the activity of methanogens is the limiting factor in the final conversion of organic

matter into methane and carbon dioxide, the optimum must be set within the desirable range.

Methane production from organic fraction of MSW has attracted special interest as a result

of the generation of renewable energy. Anaerobic fermentation of kitchen refuse is seen as

an approach to mitigate the large quantity of MSW dumped in landfills. Various methane

generation systems and their potential have been reviewed by Gunaseelan (12).

There are several important factors that affect the methane production from kitchen refuse.

Firstly, the organic loading rate (OLR), which is equivalent to the amount of organic matter

to be stabilized by microorganisms. As reported by Gallert and Winter (13), the highest OLR

achieved was 9.4 kg/m3 /day at about 65% volatile solids (VS) removal. However, the performance of a full-scale plant treating kitchen refuse is wider, between 5 and 14 kg/m3 /day of

OLR with 55–77% VS removal efficiency. This large variation is governed by the properties of