Composting and Solid Waste Management

in Dhaka City

Md. Niamul Bari, Md. Kumruzzaman, Mohammad Harun ur Rashid,

and Md. Muzibur Rahman

Abstract Solid Waste Management (SWM) is one of the major environmental

problems in many municipal towns and cities throughout the world. In most of the
cases, municipal authorities are struggling to find the best method to manage their
residents’ wastes. Approximately 3,500–4,000 metric tons of solid waste is gener-
ated in Dhaka City. Nearly 50% of generated solid waste is collected and dumped
as crude landfill. The rest of the generated wastes remain uncollected and create
serious environmental hazard in Dhaka City and uninhabitable situation/dismal for
its dwellers. However, a little research works are conducted to find the appropriate
solution of the problem. Recently, Waste Concern (Non Government Organization)
takes initiative to tackle the problem employing composting technique in a small
community such as Mirpur in Dhaka. Wastes are collected as house-to-house basis
by rickshaw van. Subsequently, the inorganic parts are sorted out from the waste
and organic parts are converted into compost (organic fertilizer) using windrow
type aerator. In this study, the applicability of composting operation is studied in
terms of technical, economical, social and environmental aspects as an alterna-
tive option of solid waste management. Also, a thorough investigation is carried
out among the house owners/dwellers on environmental condition due to applica-
tion of such method. Primary result indicates that this method is technically sound,
environmentally safe, cost effective and socially viable.

Keywords Composting · Community · Solid Waste Management

1 Introduction

Solid Waste Management (SWM) is one of the major environmental problems in

many municipal towns and cities. In most cases municipal authorities are struggling

Md.N. Bari (B)

Department of Civil Engineering, Rajshahi University of Engineering and Technology, Rajshahi,
Bangladesh
e-mail: niamulbari@yahoo.com

H. Gökçekuş et al. (eds.), Survival and Sustainability, Environmental Earth Sciences, 815
DOI 10.1007/978-3-540-95991-5_76,  C Springer-Verlag Berlin Heidelberg 2011
816 Md.N. Bari et al.

to find the best method to manage their residents’ wastes. The population of Dhaka,
the capital of Bangladesh, is growing at a phenomenal rate overwhelming all the
efforts to improve the living conditions and posing an enormous challenge to those
responsible for management of its development and providing urban services to
citizens. Approximately 3,500–4,000 metric tons of solid waste is generated per
day, with an average generation rate of 0.5 kg/cap/day, from various residential,
commercial and industrial activities [1]. Only 50% of this is collected and some of
it is dumped as landfill [2]. The rest of the generated wastes remain uncollected,
which makes environmental scenarios of Dhaka City gloomy and dismal for its
dwellers.
A Non Government Organization (NGO) named Waste Concern started com-
munity based waste management programs by employing composting at Mirpur,
Dhalpur, Green Road and Bailey Road in Dhaka. Wastes are collected from house
to house by rickshaw van from the mentioned area and organic wastes are con-
verted into compost (organic fertilizer) after sorting into organic and inorganic part.
This study tries to assess the feasibility of composting operation as an alternative
option of solid waste management considering technical, economic, social, and
environmental aspects.

2 Methodologies
The compost plant at Mirpur section-2 operated by Waste Concern was considered
for this study. To satisfy the objectives, a thorough investigation was conducted
on number of family that are involved in this project, daily generation of waste,
composition, physical characteristic, waste collection performance, plant opera-
tion performance, production of compost, respective expenditure and income of
the project. To know the real picture of environmental condition and satisfac-
tion level of the participant family, a questionnaire survey was conducted among
the house owners at Mirpur section-2. Necessary data was collected from the
authority of Waste Concern. Thus the collected data was analyzed and made a
conclusion.

3 Study on Compost Plant at Mirpur

Waste Concern started this program in the year 1995 at Mirpur. This is the first
program. Lions Club of Mirpur supported the program by giving land beside their
office. Wastes are collected from 850 house/family. Every day approximately 3,500–
4,000 kg wastes is produced in this area. Considering average waste production is
3,750 kg/day. Hence yearly production of wastes is 1,368.75 tons. Organic wastes
are 75–80% of total generated wastes [3]. Rest inorganic wastes are disposed at
nearest DCC waste collection container. Organic wastes are converted into compost.
Compost production rate is 22.50% of organic waste [3].
Composting and Solid Waste Management in Dhaka City 817

3.1 Waste Collection and Sorting

Wastes are collected following house-to-house collection system. Only three
rickshaw-van and 6 persons are engaged in waste collection. These three rickshaw
vans are utilized for the collection of seven (7) trips of wastes. Each van is used
atleast for two trips. Collection works are started at 10 a.m. and it takes almost
six hours. Plate 1 shows the collection of waste. Collected wastes are unloaded
from rickshaw van at waste sorting shade. Then these raw wastes are sorted out into
organic and inorganic part. Organic wastes are piled for composting and inorganic
wastes are stacked for disposal by DCC waste collection truck. Plate 2, Plate 3
and Plate 4 show the waste unloading and sorting activities and inorganic waste
respectively.

Plate 1: Collection of Waste Plate 2: Waste Unloading

Plate 3: Waste Sorting Plate 4: Inorganic Waste

3.2 Composting of Waste

At Mirpur site Waste Concern used windrow type aerator for waste composting
(Fig. 1). The aerators are bamboo made in triangular shaped. Organic wastes are
piled on this triangular shaped aerator. The length, base and height of aerator are
2.44 m, 0.66 m and 0.533 m respectively. Cross sectional area of triangle is 0.176 m2
and volume is 0.43 m3 . Air has flown through this cross sectional area and along the
length of pile.
The dimension of base of wastes on aerator is 1.68 m and height is 0.92 m. Its
cross section is not accurately triangular shaped, but it may call semi parabolic. For
818 Md.N. Bari et al.

Waste for
Composting
0.92 m
Working
Way

0.533 m 2.44 m

0.75 m 1.68 m 0.75 m

0.66 m

Fig. 1 Windrow type bamboo made aerator

calculating cross sectional area it is measured an average width and it is (0.92 m +

1.68 m)/2 = 1.30 m. So cross sectional area is 1.20 m2 and volume is 2.93 m3 . The
net volume of wastes on aerator is 2.93 m3 – 0.43 m3 = 2.50 m3 .
Organic wastes are piled on aerator by a team of worker. Wastes then start to
decompose aerobically with the help of bacteria. To accelerate the decomposition
activity Waste Concern add effective microorganism (innoculums), it is called sim-
ply e.m. The decomposition period of organic wastes is in this case 25 days, but
without e.m. it takes 40 days.
Organic wastes on pile are stirred after few days interval. To control moisture and
temperature water also added. After 25 days decomposed wastes is unloaded from
aerator and stack for maturation on maturation place. Here decomposed waste is
matured within 15 days. Then the matured compost is screened and graded as finish
product. This finished product (compost/organic fertilizer) is stored for sale. Plate 5
and Plate 6 show the waste composting and compost screening respectively.

Plate 5: Waste composting Plate 6: Compost screening

3.3 Performance Study of Worker

Composting operation is being done manually. It is labor-intensive operation. In

this project one project manager, one office assistant and one peon are the official
Composting and Solid Waste Management in Dhaka City 819

Table 1 Performance of composting workers

Type of work Quantity (kg) Worker Time (h) Capacity (kg/cap/h)

Raw wastes sorting 3,750 8 2.00 234.00

Organic wastes piling 3,000 8 0.50 750.00
Compost unloading 675 8 0.50 168.75
Compost screening 675 6 4.00 28.00
Compost storage 675 6 0.50 225

strength. There are eight (8) workers engaged for raw wastes sorting, organic wastes
piling and decomposed wastes unloading from aerator. The time spent for these
works are 2.5 h, 0.5 h and 1.0 h respectively. They sort out about 3,750 kg of raw
wastes, piled approximately 3,000 kg organic wastes and unload from aerator 675 kg
of decomposed wastes. Again six (6) workers are engaged for screening this 675 kg
decomposed wastes after maturation. Requirement of time for this work is 6 h. After
screening compost is categorized in different grades by this time. These 6 workers
store this 675 kg of compost in only 0.5 h. The summery of performance of workers
is shown in Table 1.

3.4 Study of Density

Density of raw wastes was measured in two ways. A full bucket of raw waste was
weighted and self-weight of bucket was deduced from the gross weight. The gross
weight of raw waste was 15.50 kg and net weight was 14.50 kg. The dimension
of this bucket was measured by measuring tape. Top diameter was 0.36 m, bot-
tom diameter was 0.27 m and height was 0.34 m. Volume of bucket was calculated
0.0265 m3 . Then the density of raw waste was calculated 547.24 kg/m3. The weight
of organic waste after sorting was taken as 15.15 kg in the same bucket. Density of
organic waste was calculated 572.00 kg/m3 . After decomposition of waste, weight
was taken as 16.20 kg and density was calculated 611.23 kg/m3. The weight of fin-
ished compost after screening was taken as 16.60 kg and density was calculated
623.00 kg/m3 . This is shown in Table 2.

Table 2 Density of waste in different stage

Mixed waste Organic waste Decomposed Matured compost

(kg/m3 ) (kg/m3 ) waste (kg/m3 ) (kg/m3 )

547.24 572.00 611.23 626.40

820 Md.N. Bari et al.

3.5 Requirement of Area for Composting

Collected wastes are unloaded in a place where raw wastes are also sorted out into
the organic and inorganic wastes. It is steel angle framed tin shaded area, dimension
of which is 4.6 m × 7.6 m and covered area is 350 m2 . Composting place is also
steel angle framed tin shaded area. Composting shade is two numbers, whose one
dimension is 12.20 m × 4.88 m and second dimension is 10.67 m × 7.62 m. Total
covered area is (59.54 + 81.30) = 140.85 m2 . Decomposed wastes maturation place
is open space. It is 9.15 m × 9.15 m = 83.70 m2 . Compost screening area is steel
angle framed tin shaded place. It is 4 m × 5 m = 20 m 2 . Compost storage place is
steel angle framed tin shaded and fenced by tin. It is 12.20 m × 4.88 m = 59.54 m2 .
The project office is a brick made R.C.C. top slab single room. It is 10 m2 . The
area for internal road and open space is approximately 35.9 m2 . Total land used for
composting operation is 700 m2 . Table 3 shows the requirement of land for various
activities of composting.

Table 3 Requirement of area for compost plant

Unload
and
Area (m2 ) sorting Composting Maturation Screening Storage Office Inter road Total

350.00 140.85 83.70 20.00 59.54 10.00 35.9 700

3.6 Economic Analysis

The expenditure is mainly two types, capital cost and operation-maintenance cost.
Heads of expenditure are wastes collection, compost production, electricity & water
connection and marketing.

3.6.1 Wastes Collection Cost

Waste Concern purchased three rickshaws vans each Tk.8,000
∴ Total capital cost was 8,000 × 3 = Tk.24,000
Annual maintenance cost is 10% of capital cost = Tk.2,400
Monthly salary 5 collector is Tk.6,000@ Tk.1,200
Monthly salary of one rickshaw van driver is Tk.1,500
Total monthly salary for wastes collection is Tk.7,500
∴ Yearly total salary for wastes collection is 7,500 × .12 = Tk.90,000
Yearly expenditure for collector uniform is Tk.3,000 @ Tk.500
∴ Total annual operation and maintenance cost for waste collection is
Tk.92,900
Composting and Solid Waste Management in Dhaka City 821

3.6.2 Compost Production Cost

Capital cost of compost production due to shade construction and land purchase.
Total area of shade for wastes sorting, composting, screening compost storage and
office is (350 + 140.854 + 20 + 59.54 + 10) = 580.39 m2.
Capital cost of shade @ Tk.522.41 is Tk.303,201
Maintenance cost is 10% of capital cost = Tk.30,320
Wastes Concern did not purchase land. So, there is no expenditure for land.
Monthly salary 13 workers @ Tk.1,200 is Tk.15,600 and one worker is Tk.1,500
Monthly salary for project manager, office assistant and peon is (5,000 + 3,000 +
1,500) = Tk.9,500
∴ Yearly total salary for waste composting is (15,600 + 1,500 + 9,500) × 12 =
Tk.319,200
Yearly expenditure for worker dress @ Tk.500 is Tk.7,000
Yearly expenditure for instrument and equipment is Tk.2,500
∴ Total annual operation and maintenance cost for composting = (30,320 +
319,200 + 7,000 + 2,500) = Tk.359,020 and total capital cost is Tk.303,201

3.6.3 Water Supply and Electricity Connection Cost

They have no water supply connection of WASA. They use tube well water. So,
water supply cost is zero. Electricity supply charge is Tk.1,000 per month. So, yearly
charge is Tk.12,000.

3.6.4 Compost Marketing Cost

Waste Concern did not market compost directly. They sell compost to Map. Agro
and they improve compost by adding nutrient and Alfa Agro market this. So, they
have no marketing cost. But here marketing cost is considered as 10% of compost
production cost.

3.6.5 Annual Expenditure of Project

General Formula
Annual Cost = Capital Cost × CRF + Annual O & M Cost − Salvage value × SF
CRF! (Capital Recovery = {i(1"+ i)n } / {(1 + i)n − 1}
" ! Factor) 15
= 0.1(1 + 0.1) / (1 + 0.1) − 1 = 0.131
15
! "
SF = (Sinking Fund) = i/ {(1 + i)n − 1} = 0.1/ (1 + 0.1)15 − 1 = 0.031
i = Discount rate = 10% (assumed)
n = Design period = 15 years
Salvage value = 1% of capital cost
Annual cost of wastes collection =
Captial Cost × CRF + Annual O & M Cost − Salvage value × SF
= 24,000 × 0.131 + 92,900 − 2,400 × 0.031 = Tk.95,969
822 Md.N. Bari et al.

Annual cost of compost production =

303,201 × 0.131 + 359,020 − 30,320 × 0.031 = Tk.397,799
Annual cost of marketing = 0.1 × 397,799 = Tk.39,780
Annual cost of water and electricity = Tk.12,000
∴ Total annual expenditure = Tk.95,969 + Tk. 397,799 + Tk.39,780 + Tk.12,000 =
Tk.454,548

3.6.6 Income of the Project

Waste Concern income from the households for waste collection and compost sale.
Waste collection charge is Tk.15.00–Tk.20.00 per month. Wastes are collected from
850 households. Waste collection charge is @ Tk.20.00 from 650 households and
@ Tk.15.00 from 200 households. Selling rate of compost is @ 2.50 Tk./kg. Annual
production of compost is 246,375 kg.

∴ Income from waste collection is Tk.16,000.00 per month

∴ Annual income from waste collection is Tk.192,000.00
∴ Annual income from compost sale is Tk.615,937.50
∴ Total annual income is (Tk.192,000.00 + Tk.615,937.50) = Tk.807,937.50
∴ Net income is (Tk.807,937.50 − Tk.545,548) = Tk.262,389.50
∴ Net unit income is (262,389.5 ÷ 1,368.75) = Tk.192.00/ton of generated waste.

4 Community Response
There are 850 household are involved with the composting activity of Waste
Concern at Mirpur, Section-2. Field investigation from last week of October to sec-
ond week of November of 2002 among 137 house owner out of 850 to assess the
community response about the composting.
About 80% of 137 households were involved from the beginning of waste
collection and composting activities of Waste Concern. Cent percent household
preserved their wastes to supply to waste collector. 96% households said their
environment is non-odorous and 4% said moderately odorous. To assess the aware-
ness about composting among that house owner, there were seven questions have
asked.
Awareness about composting, compost, organic fertilizer was found cent per-
cent. Cent percent house owners were known that their produced wastes were
converted into compost by Waste Concern and about 87% house owners were
known the crop or vegetables that produced by using organic fertilizer (com-
post) are hygienic. Again 74% house owners were known about soil conditioner.
The house owners pay Tk.20.00 per month to Waste Concern for waste collec-
tion purpose. That area was mostly educated and moderately sophisticated. Those
house owners were in middle to upper middle-income level. So awareness level is
satisfactory.
Composting and Solid Waste Management in Dhaka City 823

5 Conclusion

The following conclusions are drawn on the basis of results obtained from this study
work and field investigation considering technical aspects, economic aspects, social
aspects and environmental aspects.

5.1 Technical Aspects

(i) Cent percent wastes may be collected by house-to-house wastes collection

system.
(ii) Only the inorganic non-reusable wastes are disposed of by the municipal
authority.
(iii) Total organic wastes (biodegradable) are converted into compost (an organic
fertilizer).

5.2 Economical Aspects

The net unit income from waste composting is Tk.192/ton of generated solid
waste.

5.3 Social Aspects

(i) About 80% of total generated solid wastes would be converted into compost.
In this regard it reduce the maximum volume of generated waste. It saves the
more requirements of land for sanitary landfill.
(ii) The produced compost is a good soil conditioner. It would be used as an
organic fertilizer. It would be used as a substitute of chemical fertilizer.
(iii) The compost is screened for different grades; hence it will be able to fulfill the
demand for different types of farmers.
(iv) The market value of compost is very cheaper than chemical fertilizer. It would
save the farmer’s money.
(v) It can earn extra income from wastes, which was previously creating nuisance
and polluting the environment. Now the wastes have turned into resource for
community.
(vi) It saves the scarcity of land.

5.4 Environmental Aspects

(i) Waste composting is an aerobic system and less odorous, so, it is less harmful
for environmental pollution.
824 Md.N. Bari et al.

(ii) All these analyses performed in the present study lead to the conclusion that
the composting of solid waste can be an appropriate and profitable alternative
option of solid waste management.

References
1. Ahmed MF, Rahman MM (2000) Water supply and sanitation: Rural and low-income urban
communities. ITN, Bangladesh
2. DCC (1999) Solid waste management of Dhaka city. Dhaka City Corporation, Dhaka
3. Enayetullah I, Sinha AHMM (1999) Potential Site for decentralized composting in Dhaka: A
spatial analyses. Aborjana O Paribesh, 3:3–4