1.0 INTRODUCTION

Municipal solid waste in Malaysia contains a high amount of organic matter, particular

food waste. According to the National Strategic Plan 2010 for solid waste generation, it

estimates about 45% of the municipal waste are made up of organic food waste, then

followed by other components such as paper, plastics, metals and etc. it is said that

municipal wastes in Malaysia mostly contain high organic materials from kitchen waste.

Besides, most of the municipal solid wastes are made up of nearly 70% as reported when

the waste arrives at disposal site. This is a serious matter because most of the food wastes

will just dispose at landfills. The reasons behind the fact are due to improper segregation

of municipal wastes and lack of food waste energy recovery in Malaysia.

Food waste actually can be converted into useful components such as soil fertilizer and

biomass gases sources if it is source sorted at the beginning of the process chain. As a

matter of fact, the organic fraction of municipal waste can be degraded biologically either

using aerobic and anaerobic processes. The three components of municipal solid waste

which contribute greatest interest in bioconversion processes are food waste, paper

products and agricultural wastes. Through biological conversion process, we can derive

useful by-products from organic wastes such as compost, methane gas, various proteins,

and alcohols plus other intermediate organic compounds. Source separation for food

waste in waste recycling is not commonly practiced in Malaysia due to various

constraints. These constraints include low awareness among waste generators and low

demand of products produced from the food waste such as compost.

National University of Malaysia (UKM) has recognized the importance of promoting

food waste recycling in order to increase the overall recycling rate, save resources, and

diverting solid wastes from entering the disposal sites where it can constitute a financial

burden and give rise to negative environmental impacts. Due to convenience, most of the

students in campus have habit of eating out. Hence, significant amount of food waste are

being generated from cafeterias. As an initiative to kick off the food waste recycling

activities in UKM main campus, UKM decided to select Kolej Rahim Kajai cafeteria for

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a pilot project. Before the project, only a composting recycling centre collected and

segregated the garden organic wastes around the campus. The recycling centre is locating

nearby the Faculty of Education. Most of the food wastes were mixed and disposed of at

Semenyih landfill previously. The project support initiatives on community participation

in solid waste management in UKM campus.

Figure 1.1 (above), 1.2 (left) and 1.3 (right) are showing the composting pilot project at

Kolej Rahim Kajai, UKM main campus.

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2.0 LITERATURE REVIEW

Composting is the natural process of decomposition and recycling of organic material

into a humus rich soil amendment known as compost. For any business or institution

producing food waste, this organic material can be easily decomposed into high quality

compost. Fruits, vegetables, grains, bread, meats and newspaper can be composted. Most

of these organic compounds can be eaten or grown in a field or garden. Items that cannot

be composted include plastics, grease, glass and metals. Plastic bags, silverware, drinking

straws, bottles and polystyrene are chemical-formed compounds that cannot be

decomposed.

Food waste has unique properties as a raw compost agent due to its high moisture content

and low physical structure. Therefore, it is important to mix fresh food waste with

buckling agent that will absorb some of the excess moisture as well as add structure to the

mix. Composting helps to optimise nutrient management and the land application of

compost may contribute to combat soil organic matter decline and soil erosion. (Tweib,

Rahman & Kalil 2011) The application of compost into land is considered as a way of

maintaining or restoring the quality of soils, mainly because of the fertilizing or

improving properties of organic matter that contained in them.

Like other recycling methods, composting of food waste can help divert more wastes to

dump into landfill sites. Thereby, it can reduce the disposal costs, prolonging the lifespan

of the disposal sites and minimising the environmental impacts. Food waste actually is

the main contributor of emission of methane gas in landfill sites and it causes main

leachate problem due to high water content in wastes. Hence, composting technology can

help overcome these problems effectively. Furthermore, compost is a very valuable

product that acts as fertiliser or soil conditioner in farming, gardening and landscape

activities. (Bhd n.d.)

Composting of organic materials has a very long history and commonly employed to

recycle organic matter back into the soil to maintain soil fertility. The recent increased

interest in composting has arisen because of the need for environmental waste

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management and treatment technologies. Composting is seen as an environmentally

acceptable method of waste treatment. (Tweib et al. 2011) On the other words,

composting also can be defined as an accelerated process of natural decomposition of

organic matters into compost by microorganisms, mainly bacteria and fungi under the

presence of oxygen. The compost produced after the waste treatment mainly contains

nitrogen, phosphate, sulphur, potash and smaller amount but useful minerals, all of which

can help to improve plant growth and yield. Besides, compost also contains beneficial

microorganism that can suppress plant diseases and pests. Hence, it is very useful to

remediate contaminated land sites.

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3.0 METHODOLOGY & PROCEDURES

The pilot project of composting process was carried out in Kolej Rahim Kajai throughout

period of 25 days. An observation of composting process was undergoing from day to

day to measure and test about the effectiveness of composting by using rotary bins to

compose the food waste. It is very important for us to investigate the condition of

compost materials that stored inside the rotary bins. In order to make comparison, we

measured and recorded the quantity of food waste, quantity of leachate produced,

moisture content of waste and its temperature during composting process.

The steps are repeated for 25 days. Food waste will be collected from the food residues

that left in cafeteria Kolej Rahim Kajai. It is also expected to document, archive and

share all the relevant data so that they are available for careful scrutiny by other groups

by giving everyone of us the opportunity to verify the results. This practice will allow

statistical measures of the reliability of these data to be established. This is an

investigation of composting activities by using rotary bins whether can behaves as

predicted by theories and its hypothesis. The testing of effectiveness of composting

activity in UKM also was carried out to determine whether observation of real world

agree with or conflict with the prediction derived from an hypothesis.

Experiment was conducted in the small cabin that nearby the cafeteria of Kolej Rahim

Kajai. At the beginning, we need to collect the food waste from cafeteria which is thrown

into a plastic bucket. The food waste is necessary to cover up with a biodegradable plastic

cover to prevent flies have audacity to lay their eggs in the rotting food and affect the

accuracy of testing experiment. After collecting food wastes, they need to be weighing

with water dipper as the reference. Next, the weighted food waste was inserted into

composting rotary bins.

Effective microbes (EM) were prepared for the experiment. It need to readily prepare

according to the ratio of food waste: EM in 2:1. The effective microbes were then poured

into composting rotary bin together with food waste. However, it were only poured into

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rotary bin with separating 2 portions for each part in composting rotary bin. After that,

the coconut fiber was placed into the composting rotary bin as well. The portion of

coconut fiber needs to be adjusted according to ratio that made up of food waste and

coconut fiber (2:1). Coconut fibers are placed into composting rotary bin for every time

the composting activity is carrying out.

After placing the necessary ingredients into the rotary bin in adequate portion and good

proportion, the composting bin start to rotate by hand in suitable speed. The hand rotating

was lasting around 10 minutes to ensure all the compost ingredients mix together well,

possible errors could be minimized. Right after 10 minutes, the rise of temperature and

water content in food waste were observed if any changes and thus recorded. In overall,

all the relevant physical data need to recorded which including the weight of food waste,

EM portion, weight of coconut fiber inserted, risen in temperature, water content and the

volume of leachate leaking out.

Then, the steps above were repeated as follow until the volume of food waste fill up three

quarters (3/4) of the capacity of composting rotary bin. At the end of experiment, the

food waste is composted within a period of 4 weeks. It was then taken out all from rotary

bin. The final weight of food waste will be recorded in the final reading table. After all is

taken out, it is then transferring to another larger composting bin which right next to

composting rotary kin. Process of curing of composted food waste will then take place to

encourage food waste to be treated into a better quality of compost.

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4.0 RESULTS

TarikhBerat sisa makanan

(kg)

Berat mikrob

efektif (kg)

Berat sabut

kelapa (kg)

Kuantiti air

kurasan (mL)

Kandungan kelembapan

(%)

Suhu (oC)

8/10/13 - - - - - -9/10/13 - - - - - -10/10/13 2.1 1.05 1.05 10 - 3811/10/13 - - - - - -17/10/13 - - - - - -18/10/13 7.2 0.7 0.3 100 - 2821/10/13 1.2 0.6 0.6 30 3822/10/13 - - - - - -23/10/13 3.6 0.6 0.4 60 - 3524/10/13 1 0.65 0.05 - - 4525/10/13 1.55 0.775 0.755 60 - 3728/10/13 0.72 0.36 0.36 25 - 3529/10/13 1 gayung ¼ gayung ½ gayung - - 3230/10/13 2.1 0.2 0.2 0.40 - 3631/10/13 1.4 0.6 0.6 60 371/11/13 - - - - - -11/11/1312/11/13 1.3 0.85 0.20 60 - 3913/11/13 1.8 0.9 0.9 80 - 3914/11/13 - - - - - -15/11/13 1 gayung ¼ gayung ½ gayung - - 3218/11/13 1.4 0.1 0.1 60 - 3919/11/13 2.2 0.5 0.9 70 3920/11/13 0.9 0 0.45 - - 4521/11/13 - - - - - -

Table 4.1: Data of Composting Food Waste in Kolej Rahim Kajai

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Date 5 December 2013

Part of Composting Rotary Bin Part 1 Part 2

Weight of Composted Food Waste 11 12.5

Temperature (Celsius) 31 29

Water Content - -

Physical Properties Odourless, Dark Brown, Soil Like Texture

Table 4.2: Data of Composted Food Waste After Composting Activity

The physical look of products obtained from the composting process is dark brown

appearance with soil-like texture. Besides, it is odourless and does not possess any

unpleasant smell.

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5.0 DISCUSSION

Composting is the decomposition of organic wastes in the presence of oxygen (air).

During the process, composting will produce heat energy, water, emission of carbon

dioxide and nitrogen. Composting is suitable to used for treating any kind of organic food

waste, however, effective composting requires the right blend of ingredients and

conditions. These include moisture contents of around 60-70% and carbon to nitrogen

ratios (C/N) of 30/1. Any significant variation will inhibit the degradation of composting

process. Generally wood and paper provide significant source of carbon while food and

organic waste provide nitrogen. Therefore, it is essential to ensure an adequate supply of

oxygen throughout process and ventilation of the waste, either foced ventilation or

passive ventilation.

Food waste is highly susceptible to odor production, mainly ammonia and large

quantities of leachate. The best prevention for odor is a well-aerated pile that remains

aerobic and free of standing water. Leachate can be reduced through aeration and

sufficient amounts of a high carbon bulking agent. It is normal to have some odor and

leachate production. Furthermore, captured leachate can be reapplied to the compost.

Figure 5.1 shows the concept of composting method

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Figure 5.2 shows the conventional bin system which allow good air circulation,

inexpensive and require little labor.

5.1 Important Parameters of Composting Process

No. Parameters1 Water content2 Oxygen Demand3 Nutrients4 Temperature5 PH6 Time

Water content/ Moisture content- A moisture content of 60 percent is optimal for

microorganisms to breakdown the compost. Moisture contents above 70 percent create

anaerobic conditions, slow down the process and can create foul odors. Moisture below

50 percent also slows down the decomposition process. The moisture content of fresh

food waste is 80 to 90 percent, sawdust is 25 percent, and yard waste is 70 percent.

Compost with a proper moisture content will form a clump and will slightly wet your

hand when squeezed. If the clump drips water, it is too wet and may require additional

aeration or more bulking agent. If the compost falls through your fingers, it is too dry and

may need water additions or more food waste.

Oxygen Demand- oxygen is essential for optimum microorganism populations to

effectively breakdown the composting material. This can be done by turning, mixing, the

use of blowers, fans, aeration tubes, aeration holes, or raising the compost off the ground.

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Nutrients- Carbon to nitrogen ratio (C:N) is important for bacteria to process organic

material into compost. The optimum ratio to begin composting is 30:1. If the ratio

increases decomposition is slowed, the ratio decreases foul odors and nitrogen loss can

occur. Food waste is typically 15:1.

Temperature- High temperatures are essential for destruction of pathogenic

organisms and undesirable weed seeds. Also, decomposition is more rapid in the

thermophilic temperature range. The optimum temperature range is around 55-65 celcius.

Since few thermophilic organisms are only actively carry on decomposition above 65

degree celcius, therefore it is undesirable to have temperatures above this for extended

periods. Eggs of parasites, cysts and flies may have survived in the compost stack for few

days when the temperature is around 55 degree celcius, therefore all the materials should

be subjected to a temperature of at least 60 degree celcius for safety. Temperature of the

compost is important while biological activity takes place in the decomposition process.

Low outside temperature slow down the process, while warmer conditions speed up the

process.

PH- PH levels from 6.0 to 7.8 are considered high quality compost. Proper C:N ratios

should create optimum pH levels. Starting with a fairly neutral pH will ensure high levels

of microorganisms for efficient decomposition.

Time- Time of composting food waste is needed under control within suitable period so

that mature compost can be produced. The quality of compost will be deteriorated if

extended too long period. After three or four days, give the compost air by mixing and

turning it over, then turn every three days until the compost is ready, usually in 14-21

days. Remember, frequent turning and aeration is the secret of successful composting.

5.2 Effective Microbes (EM)

Microorganisms are tiny units of life that are too small to be seen with the naked eye and

they exist everywhere in nature. Microorganisms are crucial for maintaining the

ecological balance. They carry out chemical processes that make it possible for all other

organisms including humans to live. There are friendly guys of the microbial worlds

known as beneficial microorganisms and a not so friendly group called pathogens that are

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harmful and capable of producing disease, decay and pollution. In 1982 Dr. Higa from

the University of Ryukyus, Okinawa Japan, discovered a specific group of naturally

occurring beneficial microorganisms with an amazing ability to revive, restore, and

preserve. He named this group E.M. (effective microorganisms/microbes). EM is a liquid

bacterial product comprising three groups of microbes: yeast, photosynthetic bacteria and

lactic acid bacteria. Effective microbes will work together with local and native

beneficial microbes in creating a synergy among microorganisms and larger form of life

including insects, worms, pet and livestock, and peoples.

EM is a combination of useful regenerative microorganisms that exist freely in nature and

are not manipulated in any way. The purpose of adding EM into composting process is to

increase the process productivity and to suppress both diseases and weeds growth. In the

same time, turning food organic waste into valuable organic materials as well. Fungi in

EM bring about fermentation these break down the organic substances quickly. This

suppresses smell and prevents damage that could be caused by harmful insects. Besides,

photosynthesis bacteria play the leading role in the activity of EM. They synthesise useful

substances from the secretions of roots, organic matter and/or harmful gases (e.g.

hydrogen sulphide) by using sunlight and the heat of soil as sources of energy. They

contribute to a better use of sunlight or, in other words, better photosynthesis. The

metabolites developed by these micro-organisms are directly absorbed into plants. In

addition, these bacteria increase the number of other bacteria and act as nitrogen binders.

Figure 5.3: Effective Microbes

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5.3 Bad Odours during Composting

During the observation of experiment, there are some few days bad smell odour had

come out from the composting rotary kin. It is obvious and unpleasant smell. The giving

off of ammonia-like smell is because it may contains too many nitrogen rich materials.

The ratio of C:N is not in an appropriate proportion. Decompositions will only occur

effectively when we have an equal balance of carbon rich materials and nitrogen rich

materials. To correct the nitrogen- carbon ratio in the rotary pile, we just need to add

more coconut fibres into it and rotate the rotary bin so that to aerate it.

On the other hand, we also observe leachate come out during the composting progress.

This is because the water content of food waste is too high and the leachate cannot

sustain itself and flowed out. Besides, sometimes the compost heap smells like rotten

eggs or vinegar due to the compost is too wet. The compost pile is too damp as a wrung

out sponge. In order to solve leachate problem, we should dry out the compost heap by

rotate it more and add more carbon browns like coconut fibres or even newspaper to

absorb the leachate. Furthermore, we should wisely control and adjust the watering

schedule, so that we are not over watering the compost pile, especially during wet

seasons.

Aside of that, the lack of oxygen may also cause the compost pile to smell like eggs or

vinegar. However, the problem can be solved easily by rotate the rotary bin to aerate the

compost.

During the experiment, some compost quality do not mature too well as there were not

heating up, means that materials are not decompose yet. There are several reasons why

the materials cannot be decomposed. The compost heap may not have enough materials

to kick start the decomposition process. Therefore, we should need to add more food

waste to measure rotary bin recorded the volume of food waste marked enough 3 quarters

of its height. One of the reason the heap does not heating up might be the compost pile is

too dry, as too many coconut fibres added in. Adding more water into it could help solve

the problem.

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6.0 RECOMMENDATIONS

6.1 Marketing Values and Application of Compost

Compost has many uses on the farm. It can be used as a soil amendment to improve soil

structure, infiltration rate, water holding capacity, and soil quality. It will increase soil

microorganism populations, soil organic matter and humus. Compost can also be used as

a fertilizer supplement for nitrogen, phosphorous, potassium, and trace elements.

Compost will improve the quality of almost any soil, and for this reason it is most often

considered a soil conditioner. Compost improves the structure and texture of the soil

enabling it to better retain nutrients, moisture, and air for the betterment of plants.

Aggregates are groups of particles loosely bound together by secretions of worms and

compost bacteria giving it this crumbly appearance. Crumbly soil allows air to penetrate

and holds moisture well but allows excess water to drain away. Tender young roots also

have an easier time penetrating into the soil. Therefore, compost helps improve all soil

types, especially sandy and heavy clay soils.

 Mature compost does not has objectionable odor, therefore suitable to be used

suppressing insect pests and soil borne plant pathogens and act as a fungicide. The

compost produced in Kolej Rahim Kajai can be used as an alternative fertilizer to

improve and control the quality of plant grow surround UKM. It can suppress soil borne

diseases to attack trees and flowers. Besides, it is able to cut pesticide use as compost

applications as a part of organic matter management system. Thereby, it can reduce the

financial cost to buy artificial chemical fertilizer and enhance the lifespan of floras in

main campus.

Compost can be used to increase pasture quality in intensively managed grazing systems.

Compost does not decrease palatability of a pasture as raw manure does. This can be very

important to farmers who no longer produce row crops where raw manure was generally

applied. Convenience is also an advantage of compost, because it is a stable product it

can be stored and applied when it fits the farmers schedule and the field does not have to

be taken out of production. Compost can also be used as a much for trees, orchards,

landscapes, lawns, gardens, and makes an excellent potting mix.

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Additional uses for compost include vegetable production, field crops, annual forest

plantings, sod farms, greenhouse crops, mined lands, roads and recreation areas. To be

commercially viable, supplies of raw materials must be reliable and potential market for

mature compost use must be developed.

A study of solid waste composition at UKM reported that 46.5% is compostable. (Tweib

et al. 2011) However, around 28% of food wastes have been dumped into landfill sites.

As landfill space and openings decrease, there will undoubtedly be more pressure to

compost food waste along with all organic waste. As tipping fees increase, it becomes

prohibitively more expensive to landfill. Hence, compost may become an attractive

financial alternative, as well as a value-added opportunity.

As agricultural practices continue to exhaust soils and deplete organic matter, compost

will be integral in maintaining soil fertility. Landscape, nursery, public agency and

homeowner demand for high quality compost continues to increase. Compost is an

essential product in increasing amounts of land reclamation projects. Compost also plays

an important role in more environmentally regulated and environmentally aware

agricultural systems. For many livestock, poultry, and sustainable and alternative

agriculture operations, compost and composting may be the best choice as well as

opportunity for added income.

6.2 Management of Cafeteria Worker

The success of implementing compost programme largely depends on rapid cooperation

with cafeteria workers in main campus UKM. I think authority in university campus

should hold a small scale of business joint venture with the local cafeterias. University

can buy the food wastes from cafeteria and thus collect it into a centre composting

facility to process all the food wastes into useable commercial products. Besides, by

providing adequate bin system that segregate food waste individually can encourage

more collecting of food waste in cafeteria. For instance, we can modify the conventional

bin system exist in cafeteria into integrated bin systems that separate the types of garbage

according into 4 types, which are plastic, paper, organic waste and glass.

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In order to reach cafeteria worker, it is also necessary to involve cafeteria worker in

compost program by seminar talk and campaign. Experts and students help to educate

and raise the awareness of workers about the benefits and importance of composting

organic wastes. It is good to expose them about the whole flow diagram of composting

food waste and guide them with an established standard and guidelines. It would help and

remind them to understand better the principles of handling organic waste.

Besides, we can actually ask favors from cafeteria workers to involve themselves in the

efforts to compost food wastes in the small cabin where composting facilities are well

equipped. As a reward, we can appreciate their effort in return of money reward or cash

voucher which can help them reduce daily financial costs such as petrol voucher or food

coupon.

6.3 Composting Management in Kolej Rahim Kajai

The composting management in kolej rahim kajai need more cooperation from master

students and undergraduate students. As far as observed, the small scale composting

facility does not operate frequently as lacking of operator and money budget to hire

someone picking up the food wastes. The cafeteria workers do not know very much about

the existing of such facility in kolej rahim kajai. Therefore, it is a concern and need

attention from university authority.

 Health concerns relating to compost are dependent both on the individual and on the

material being composted. While few human pathogenic organisms are found in

vegetative wastes, hence normal sanitary measures such like washing hands before

touching food, eyes and etc are very important. Although most people are unlikely to

have any problems, there are a few concerns which place some individuals at risk.

Peoples whoever are sensitive to fungi should put on mask and hand gloves before

turning the composting bin.

The facility of composting system in kolej rahim kajai is setting up indoor. Therefore,

these bins need to provide adequate moisture, heat retention, and air flow to facilitate

aerobic, heat-producing decomposition of organic matter. Composting can also be carried

out right in the classroom, in containers ranging in size from soda bottles to garbage cans.

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Because these units are so much smaller than the outdoor bins, they need to be carefully

designed to provide proper conditions for aerobic, heat-producing composting to occur.

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7.0 EVALUATION

7.1 Selection of Composting Treatment Technology at Rahim Kajai College

Food waste is suitable for biological treatment such as composting method. Composting

is a managed system that uses microbial activity to degrade raw organic materials, so that

the end-product is relatively stable, reduced in quantity when compared to the initial

amount of waste, and free from offensive odors. Composting can be done on a large or

small scale, with the management requirements and intensity increasing dramatically as

system size increases.

The composting treatment technology being applied at Rahim Kajai College is using

rotating composter bin. It features and benefits is to let us make perfect compost from the

cafeteria waste quickly, easily and hygienically. It is a 'continuous-use' dual chamber

composter, so the new material can be added to one compartment while the other

matures. Due to its insulation, this composter has a smaller capacity of 4.5 cubic feet. It

has attractive design and high quality powder-coated steel construction with a side vents

provide aeration which speeds composting. Rotating composter drum is fully-enclosed

and pest resistant and set up to be either freestanding or mounted.

Figure 7.1.1

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Rotating Composter Bin

Figure 7.1.2

Rotating Composter Bin being applied at Rahim Kajai College

This rotating composter is constructed for easy rotation or simply turn by hand after

adding waste. A fresh waste was collected from Rahim Kajai College Cafeteria is brought

into direct contact with decaying waste, so it processes efficiently with the adds of air to

the mixture, providing oxygen that is vital for the process.

In practice, using the composter bins to treat food wastes in Rahim Kajai College

cafeterias is not the best solution because this system needs intensive proper care and

takes a longer period to achieve its maturity, in example more than 12 weeks. If this has

to be applied, then there will be a lot of waiting time to mature the food waste in bins

outside Rahim Kajai College cafeterias, and thus requiring larger areas.

However, this practice on composting of food waste using composter bin is a good start

for UKM to discover better control of composting system which suits the campus

environment and surroundings. All data gathered from this work are useful as base line

information for future research on composting systems in the UKM campus.

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7.2 Comparison of Composting Technology of Food Waste at Rahim Kajai

College and Garden Waste at Faculty of Education

For the composting organic waste at Rahim Kajai College, food waste must be collected

from Rahim Kajai College cafeteria at UKM campus. Daily collections of cafeteria food

waste were variable. The food waste was first separated from inorganic waste and put in

the biodegradable plastics by the café workers. Then it is grinded using a food processor

and then weighed and loaded into the composter bins. All the bins were filled up with

food wastes up to ¾ of the bin.

Generally, only food waste (consisting of fruit, vegetables and leftover food), sawdust,

and soil were being used. The effective microorganism (EM) that consists of mixed

cultures of beneficial and naturally occurring microorganisms that can be applied as

inoculants to increase the microbial diversity of soils and plants was used to enhance the

process with the coconut husk and enhance decomposition of organic matter. The

parameters that need to be controlled during the process such as oxygen requirement,

moisture content, water, temperature

Otherwise, composting of garden waste at Faculty of Education emphasize the waste

generated from any parts of trees / plants either small or large which are not used and

generated within the faculty area. The example of garden waste are weeds, grass, leaves,

branches, roots, flowers and others.

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Figure 7.2.1

Composting Garden Waste at Faculty of Education

By the implemented windrow method in UKM composting facility, the wastes are piled

in elongated rows and will turned regularly. Raw materials can be added as part of the

pile formation. Windrow shapes and sizes vary, depending on the climate, equipment and

material used. The turning schedule during composting varies from operation to

operation, depending on the pile temperature, season, labor availability and the desired

compost quality. The time required to complete the composting process ranges from five

to ten weeks, depending on the type of material being composted and the turning

frequency.

The area required for composting depends on the amount of waste to be received and the

amount of bulking agents required. A roof over the compost windrow is required.

Excessive rain may slow the composting process by causing anaerobic zones to develop.

The roof is applied for all the required spaces. The floor is designed to make the liquid

leachate from the compost flow freely to a central point for collection, which is applied to

the windrow when the windrow becomes too dry. Sprinklers is installed to spread water

evenly over the composting mass. The sprinkler connected to a water storage and

rainwater-harvesting tank. The roof of the composting shed specially designed to collect

rainwater from the rooftops. Beams is built along the composting shed to control runoff

and leachate migration.

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By planning and proposing a yard waste composting facility that considers the

technology of each method, this facility will successfully process the waste efficiently in

a sustainable manner.

Figure 7.2.2

Pilot plant of composting with a windrows method

7.3 Comparison of Composting Technology with Anaerobic Digestion or Refused

Derive Fuel (DRF) on treating organic waste.

Much of the progress to date in waste innovation seems to have been in the area of

development of new technologies to treat wastes. However, there is evidence of many

innovative waste management approaches focusing on waste prevention, waste

minimisation, source separated collection and specific technologies for treating particular

waste streams.

A range of systems for processing mixed waste have been examined in this study. These

vary from composting processes which are net consumers of energy to anaerobic

digestion processes, which are net exporters of energy. The applicability of certain

technologies depends very much on a range of issues such as waste stream

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characteristics, distance to markets, the financial situation of local government and waste

quantities.

When a mixed waste composting process is geared towards producing a saleable

compost, it becomes more complicated and expensive to operate, and the amount of

residual material increases, as contaminants are removed from the incoming waste stream

or screened from the raw compost to meet higher standards. Mixed waste treatment

processes therefore carry a greater risk as far as acceptance of the resulting compost than

composting processes that are based on treating separated food and garden wastes.

Anaerobic digestion processes are more technically complex than composting processes,

and therefore have a higher capital cost, but they produce a commodity (green energy)

that is in high demand. Generally there is less residual material for landfill disposal than

comparable composting processes.

7.3.1 Composting Process

During composting process, biodegradable material is decomposed into carbon dioxide

(CO2), water (H20), and heat through microbial respiration in the presence of oxygen

leaving a stabilised residual solid material, compos. If source segregated biodegradable

material is treated, oxygen is often supplied passively through the presence of air or

through mechanical turning.

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Figure 7.3.1.1

Composting Process

The process progresses biodegradable material is converted into carbon dioxide, water,

and heat, which are lost to the atmosphere. The material remaining consists of a mixture

of non-biodegradable materials; recalcitrant organics; microbes and microbial remains;

and a complex of decomposition by-products called humus. This stabilised and dried

mixture is known as compost.

7.3.2 Anaerobic Digestion Process

During Anaerobic Digestion, biodegradable material is converted into methane (CH4)

and carbon dioxide (together known as biogas), and water, through microbial

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fermentation in the absence of oxygen, leaving a partially stabilised wet organic mixture.

Figure 7.3.1.2

Anaerobic Digestion

The process progresses biodegradable material is converted into a combustible gas

known as ‘biogas’ primarily consisting of a mixture of methane and carbon dioxide.

Biogas can be burned for heat and/or electricity production, or cleaned for use as a fuel or

injection into the national grid. The material remaining consists of a wet solid or liquid

suspension of non-biodegradable materials; recalcitrant organics; microbes (biomass) and

microbial remains; and decomposition by-products. This partially stabilised wet mixture

is known as ‘digestate’. This wet mixture can be de-watered into its solid and liquid

fractions. Sometimes these two fractions may both be referred to as ‘digestate’, but for

clarity they will be referred to as digestate (solid) and liquor (liquid).

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8.0 Material Recovery Facilities (MRF)

8.1 Introduction

Internationally , MRF are relatively new in the solid waste management field , but their

popularity is fast increasing. In early 1980, the first MRF was established in Groton ,

Connecticut. An obvious question to many parties is the sudden increased interest in

MRF as an approach to processing solid waste. The interest is coming from desire to

reduce MSW goes to landfill , achieve this reduction by maximizing recycling and MRF

simplify generator requirement, and thus increase participation in recycling. A Material

Recovery Facility (MRF) is a building to receive, sort, process and store recyclable

materials to be shipped and marketed to end-users. A materials recovery facility accepts

materials, whether source separated or mixed, and separates, processes and stores them

for later use as raw materials for remanufacturing and reprocessing.

MRF is defined as a central operation where commingled or sources separated

recyclables are processed mechanically or manually . Malaysian are encouraged to

participate in a MRF operation and as a result of this participation , higher volumes of

materials will be taken from the solid waste stream. Second, because of the commingled

nature of recyclables, collection vehicles need can be simplified. Need for

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multicompartment vehicles is reduces; normally only two compartment are required .

Collection times and cost can be also be reduced because less time is taken at the curb

sorting materials or emptying several containers. Finally most advocates believe that

materials processed through MRFs are more marketable. They feel that the products are

cleaner , can better meet industry standards and that the consistent volume of material

that they can generates helps to assure a market.

8.2 MRF Process Flow Diagram

All the incoming waste are unloaded and place onto convey belt in preparation for

sorting. The condition for incoming waste by referring to handbook material recovery

facilities for municipal solid waste by Office of Research and Development Washington

DC 20460 is the MRF just receives only sources separated materials and are delivered in

two distinct forms . One stream consists of paper and the other of commingled containers.

Secondly materials that would delivered to the facility in the commingled container

stream include of ferrous metal , aluminum , glass PET and HDPE. Thirdly , recycle

materials are delivered to the facility via commercial collection vehicles.

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Then the incoming waste from step 1 will fall into incline convey and sorted by gravity

and shape. For example , the heavier materials such as container will fall due to gravity

and light material such as beg plastic and paper will go through the upper conveyer due to

blow of air .

After that ,workers sort out trash collect the recyclable by hand by their different

characteristic such as colors.

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Fourthly , paper product are drop into holding container and baling

Super strong magnet that attract steel, picks the steel product up and move them to other

conveyer that move them to their appropriate container

Magnet don’t attract aluminums so it sorted by Eddy current which shoot the aluminums

product into the catch bears.

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The heavier glass fall into a pit while the lighter plastic material roll on to the next

conveyer for further sorting.

The plastics are scan and sorted by pipes of air into group of types and colour

Plastic materials that scanner don’t pick up are further sorted by workers into specific

groups.

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After all the materials have been sort and process expect for the glass, they are bales

After baling, the recyclable can weight 1000lbs – 1500 lbs

Manufactures buys this bales and create new product from that recycle materials

At last the condition of finished products will refer to this ( Handbook Material Recovery

Facilities For Municipal Solid Waste By Office Of Research And Development

Washington DC 20460 ) :

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8.3 Equipment Needed in Operation of MRF

8.3.1 Belt conveyors

This is the most common piece of equipment for handling materials in a MRF. And

there’s many of type of conveyors in MRF which is :

8.3.1.1 Through type

In general the through type belt conveyor will use troughing idler rolls which cause the

conveyor belt to form of concave contour with its slide sloping with a horizontal plane .

The purpose of this cross sectional concavity is to retain free flowing materials (eg

aluminum cans, bottles , crushed glass and etc and to minimize or prevent spillage.

8.3.1.2 Flat belt type

Flat belt conveyors are popularity utilized in the sorting process at a MRF for they permit

easy access to the materials carried on the belt. When a flat belt conveyor is used in an

inclined position, its often supplied with cleats and skirt boards for the full length of the

conveyor in order to more positively convey the materials and prevent spillage.

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8.3.1.3 Apron conveyor

An apron conveyor consists of steel pans (flat or contoured) supported by chains and is

used in application in which the conveyor may be subject to substantial impact and abuse.

Guide rollers riding on the steel rails minimize the frictional forces.

8.3.1.4 Screw conveyor

The screw conveyor may be used to transport dry, dense , free flowing materials for

examples tin cans formed as nuggets. Screw conveyor have also been used for bin

discharge and as metering feed devices. These units are not designed to transport stringy ,

abrasive or very wet materials.

8.3.1.5 Pneumatic conveyor

A pneumatic conveyor is to utilizes a stream of air to convey suspendable materials

examples aluminum cans or dust through a tube. Pneumatic conveyors may utilize either

vacuum or a positive pressure

8.3.2 Separator

8.3.2.1 Magnetic separator

Magnetic separation is a relatively simple unit process and is used to recover ferrous

metal from the commingled waste stream. The magnetic head pulley conveyor is

arranged so that in its operation, the materials to be sorted is passed over the pulley in

such a manner that the nonferrous materials will fall along a different trajectory than will

the ferrous materials. The drum magnet assembly can be installed for either overfeed or

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underfeed and directs the ferrous along the trajectory other than that taken by the

nonferrous materials.

8.3.2.2 Eddy current device (Aluminum separator)

An aluminum separator employs either a permanent magnetic or electromagnetic field to

generate an electrical current eddy which causes aluminum cans (nonferrous metals) to be

ejected and separated from other materials.

8.3.2.3 Disc screen

A disc screen consist of parallel multiple shafts all rotating in the same direction. Disc are

mounted on each of these shafts, and spaced in such a fashion so that the discs on the one

shaft are located midway between the discs on an opposing shaft. Disc screen are subject

to damp and stringy material wrapping around the shafts and disc and this reducing the

interstices. At the infeed location, abrasive material (broken glass or grit) may abrade the

outside diameters of the shafts and discs so as to substantially increase the interstices.

Also large pieces of corrugates may act as a barrier to smaller material dropping through

the interstices

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\

8.3.2.4 Vibrating screen

A vibrating screen utilizes a wire mesh or perforated plate screen deck to separate

relatively dense, dry, undersize materials from less dense oversize materials. Damp,

sticky materials have a tendency to blind the screen deck and thus impair the

performance. Larger pieces of corrugated and excessive materials bed depth can

substantially decrease separation efficiency.

8.3.3 Size reduction

8.3.3.1 Plastics granulator

A plastic granulator is used to size reduce to PET or HDPE containers to a flake-like

condition. The granulated plastic is generally shipped in gaylords. Due to the relatively

large reduction in volume, substantial saving in shipping can be realized when plastic

granulation is employed. Plastics granulation is an operation that requires a relatively

high degree of maintenance and may be prone to dust generation

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8.3.3.2 Baler

Balers are used for forming bales of newsprint, corrugated , high grade paper , mixed

paper , plastics , aluminum cans and tin cans. Some balers are equipped for fully

automatic operation while others demand a considerable amount of operator attention.

8.3.4 Environmental control

8.3.4.1 Dust collection system

Shredding , granulating , crushing , baling and screening generally are dust producing

operations. Depending upon the severity of the problem , the solution can vary anywhere

from a simple dust mask for the worker, to individual dust collection at each of the dust

producers, to one or more centralized dust collection systems to serve the total needs of

the facility. Dust collection system include fans, ducting , cyclones and baghouses.

8.3.4.2 Odor control equipment

Odors can be often be reduced or eliminated by minimizing storage time of raw materials

or product followed by frequent floor washdown. Other odor control technologies include

of improved dispersion , odor masking , wet scrubbing , carbon adsorption , catalytic

incineration and thermal incineration.

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9.0 Incineration & Refuse Derive Fuel (RDF)

9.1 Introduction

A solid fuel produced by shredding municipal solid waste (MSW) . Noncombustible

materials such as glass and metals are generally removed .The residual material is sold

as-is or compressed into pellets, bricks, or logs. An alternative for landfilling MSW.

Canada and United States were using RDF incinerator for the alternative of landfilling

MSW.

History :

“Poorly designed, controlled and operated incinerators have resulted in nuisances

and have demonstrated that environmental concerns can sufficient to close

facilities.”

In United States , about 100 MSW incinerators burn about 4 percent of the annual volume

of MSW generated in United States. Whereas it is conceivable that by the year 2000 ,

one-third of the MSW will be incinerated in more than 300 MSW incinerators. Definite

trend moving toward incineration of MSW in the United States, and away from

exclusively landfilling the waste.

In Canada , the majority of municipalities are facing a crisis in the disposal of increasing

volumes of MSW Only 8% of municipal solid waste is incinerated with less than 4% in

energy from waste(EFW) facilities, less than 2% of Canada's municipal solid waste is

recycled. In the next decade, up to 50% of Canada's waste could be disposed of in EFW

facilities, with the construction of over 40 new facilities across Canada. This would

provide a potential saving of 8-120 million barrels of oil annually.

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9.2 RDF Unit Operation Process (Process Flow Diagram)

For process section , the system consists of mainly of sorting , crushing , dewatering and

drying.

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9.3 Equipment Needed In Operation Of RDF

9.3.1 Preparation for Mixed composting

In this process includes spraying the waste with chemicals to control the odour and hasten

the decomposition process. Compost is recovered through “fine refinement” in which the

waste is passed through trommel screens of varying mesh sizes. All the fines that fall

through are separated as compost to be sold.

9.3.2 Drying

The partially decayed waste is dried, either under the sun, by hot air, or by a combination

of both.

9.3.3 Manual Separation

Bulky items such as large pieces of wood, rocks, long pieces of cloth, etc. are removed by

hand before mechanical processing begins. Equipment involved in manual separation

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usually includes a sorting belt or table. Handpicking of refuse is perhaps the most

prevalent MSW handling technique.

9.3.4 Screening

It is done by passing the waste through trommel screens, most commonly rolling drums

with different mesh sizes. Trommels are attached to the conveyors at various stages of

processing and are inclined to allow oversize materials to pass along them.

9.3.5 Size Reduction

Hammer mills consist of rotating sets of swinging steel hammers through which the

waste is passed, and shear shredders are used for materials that are difficult to break apart

such as tires, mattresses, plastics

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9.3.6 Magnetic Separation

Electro-magnets are used in this step so they can be switched on or off to allow removal

of collected metals

9.3.7 Air Separation

In this step, fans are used to create a column of air moving upwards. Light materials are

blown upwards, and dense materials fall. The air carrying light materials, like paper and

plastic bags, enters a separator where these items fall out of the air stream.

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9.3.8 Incineration

Combustion of organic substances contained in waste materials . Incineration of waste

materials converts the waste into ash, flue gas, and heat.

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9.3.9 Final product

Once all of the separating and size reduction steps are complete, the final RDF product

can be formed into bricks or pellets or can be left as fluff. Each form is derived from

material separated at a particular stage in the process.

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10.0 REFERENCES

1. Bhd, E.-I. C. S. (n.d.). source separation of food waste- turning waste into compost. Kuala Lumpur, Malaysia.

2. Tweib, S. A., Rahman, R. A. & Kalil, M. S. 2011. A Literature Review on the Composting 12, 124–127.

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