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Environ Monit Assess (2011) 175:2335

DOI 10.1007/s10661-010-1490-8

Assessment of plastic waste generation

and its potential recycling of householdsolid waste in Can Tho City, Vietnam

Nguyen Phuc Thanh Yasuhiro Matsui

Takeshi Fujiwara

Received: 21 August 2009 / Accepted: 20 April 2010 / Published online: 20 May 2010 Springer Science+Business Media B.V. 2010

Abstract Plastic solid waste has become a serious

problem when considering the disposal alterna-

tives following the sequential hierarchy of sound

solid waste management. This study was under-

taken to assess the quantity and composition of

household solid waste, especially plastic waste to

identify opportunities for waste recycling. A 1-

month survey of 130 households was carried out

in Can Tho City, the capital city of the Mekong

Delta region in southern Vietnam. Household

solid waste was collected from each house-hold and classified into ten physical categories;

especially plastic waste was sorted into 22 subcat-

egories. The average household solid waste gener-

ation rate was 281.27 g/cap/day. The compostable

and recyclable shares respectively accounted for

high percentage as 80.74% and 11%. Regarding

plastic waste, the average plastic waste genera-

tion rate was 17.24 g/cap/day; plastic packaging

and plastic containers dominated with the high

percentage, 95.64% of plastic waste. Plastic shop-

ping bags were especially identified as the majorcomponent, accounting for 45.72% of total plastic

waste. Relevant factors such as household income

N. P. Thanh (B) Y. Matsui T. FujiwaraGraduate School of Environmental Science,Okayama University, Japan 3-1-1 Tsushima-naka,Okayama 700-8530, Japane-mail: [email protected],[email protected]

and household size were found to have an existing

correlation to plastic waste generation in detailed

composition. The household habits and behaviors

of plastic waste discharge and the aspects of en-

vironmental impacts and resource consumption

for plastic waste disposal alternatives were also

evaluated.

Keywords Plastic waste Household solid waste

Plastics recycling Generation rate

Physical composition

Introduction

The rapid population growth and expanding ur-

banization have caused the increase of the waste

generation and the variety of waste composi-

tion. Many cities and towns in developing coun-

tries face serious environmental degradation and

health risks due to the weak solid waste man-

agement. For effective planning of waste man-

agement, the importance of elucidating reliable

information on both the quantity and the com-

position of municipal solid waste (MSW), espe-

cially of household solid waste (HSW), has been

recognized (Dennison et al. 1996a; McDougall

et al. 2001). Many previous studies have exam-

ined HSW generation and physical HSW com-

position. Ojeda-Benitez et al. (2003), Alhumoud

et al.(2007), and Qu et al. (2009) analyzed HSW

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24 Environ Monit Assess (2011) 175:2335

generation to identify the potentials for com-

postable waste and recyclable waste.

Since the 1950s, one billion tons of plastic has

been discarded and may persist for hundreds or

even thousands of years (Weisman2007); this has

become a common problem in the last decades.

There are many recycling and recovery routesof plastic solid waste; chemical recycling (includ-

ing pyrolysis, gasification, and hydrogenation)

through which plastics can be broken back down

to a feedstock state and energy recovery by plastic

waste combustion as other fuel sources (Al-Salem

et al.2009). Recently, many studies have focused

on plastic waste; Subramanian (2000) studied on

the recycling and recovery routes of plastic waste

and Chung (2008) assessed the reliability of self-

reported waste disposal data using plastic bag

waste. They also pointed out the considerable con-tribution of plastic fraction and the urgent need

for the proper management of waste plastics.

A national report (Worldbank et al.2004) pre-

sented outline information related to MSW man-

agement in Vietnam; the plastic waste accounted

for the considerable portion of MSW. Besides,

open dumping is the main disposal method (Idris

et al.2004). Moreover, the strategies for recycling

and disposal of plastic waste at local level and

central level have not been developed.

In this study, the authors estimated the HSWgeneration rate and detailed composition in the

central city of the Mekong Delta region to identify

opportunities for waste recycling, especially for

plastic waste. The authors analyzed the current

status of plastic waste stream and the household

habits and behaviors related to plastic waste dis-

charge. The relevant effect factors to plastic waste

generation were also carried out. Furthermore,

the potential for recycling plastic HSW, the as-

pects of energy recovery potential, environmen-

tal impacts, and resource consumption of plastic

waste disposal alternatives were also evaluated.

Methodology

Organization of samples

This study estimated the HSW generation, es-

pecially plastic waste of the capital city of the

Mekong Delta region (including12 provinces and

one city) in southern Vietnam. Can Tho City

(CTC) was chosen as the representative model

for the Mekong Delta region. CTC has four cen-

tral districts and four rural districts, with an es-

timated population of 1,154,900 in 2007 and an

area of 139 km2 (GSO 2007a). For this study,the authors specifically investigated four central

districts of CTC-Ninh Kieu District (13 wards),

Binh Thuy District (six wards), Cai Rang District

(seven wards), and O Mon district (six wards)-

which collectively include 32 wards (GSO2007b).

The daily estimated MSW collection rate in CTC

is 250300 tons/day. Furthermore, the waste col-

lection is about 70% for four central districts by

Urban Environment Company (URENCO2008).

The authors intended to estimate the average

situation of four central districts of CTC. Forsampling, the authors designed to choose 70% of

samples in the wards with waste collection service,

and 30% of samples in the wards without waste

collection service. The sampling points (SPs) were

selected considering their respective geographical

distribution; the authors chose 13 wards (SPs),

from a total of 32 wards, as 5, 3, 3, and 2 wards,

respectively, from the districts Ninh Kieu, Binh

Thuy, Cai Rang, and O Mon.

Ten households were selected from each SP,

and the total sample size of the survey was 130households, including 40 households (31%) with-

out waste collection service. Figure 1portrays a

map of CTC with the location of 13 SPs.

In earlier reports of the relevant literature, the

household size affected waste discharge amounts

(Dennison et al. 1996band Bandara et al. 2007).

Therefore, the authors selected target households

according to the share of household size in CTC.

At each SP (each chosen ward), ten households

were chosen based on the share of four household

size categories; as 15%, 45%, 35%, and 5%, re-

spectively, for 12, 34, 57, and 8 and more res-

idents. The household size category followed the

population distribution category in the statistics in

Can Tho City (GSO2006).

Classification of fraction

Following the requirements of the studys objec-

tives, the classification categories of waste were

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Environ Monit Assess (2011) 175:2335 25

Fig. 1 Map of Can ThoCity with detailedlocations of samplingpoints. Source: Googlemaps (edited by theauthors)

developed to provide detailed information on

waste composition. Therefore, it was necessary

to clarify details of the composition of HSW,

such as the relative shares of recyclable and com-

postable wastes, their usage function and pur-

pose, discharge source, and hazardous wastes.

The authors referred the categories reported

from some previous relevant studies as Tanikawa

(2000), Ojeda-Benitez et al.(2003), Kawai(2007),

Burnley et al. (2007), Dahln and Lagerkvist

(2008), and Gomez et al. (2008). A table was

prepared showing classification categories of ten

physical categories (physical compositions; see

Table1) and 22 subcategories (detailed physical

compositions) for plastic waste (see Table2).

Survey framework

Sample collection was conducted in two stages of

surveys: the questionnaire survey and waste gen-

eration survey. The questionnaire survey carried

out on randomly selected households in chosen

areas for getting required information and house-

hold selection. The selected respondents of the

questionnaire survey should be a household mem-

ber, who is responsible for discharging or recycling

HSW. After the questionnaire survey, the proper

households based on household size category

Table 1 Household sold waste generation in amounts andpercentage (wet weight)

Fractions % g/cap/day SD

Plastic 6.13 17.24 11.01

Paper 4.87 13.70 18.55

Food waste 84.42 237.44 134.29

Rubber and leather 0.23 0.64 4.03

Grass and wood 1.65 4.65 22.68

Textile 0.33 0.92 2.78

Metal 0.69 1.93 3.01

Glass 1.00 2.80 4.80

Ceramic 0.12 0.32 1.08

Miscellaneous 0.58 1.62 11.26

Total 100 281.27 147.20

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Table 2 Plastic waste generation by subcategories inamounts and percentage (wet weight)

Fractions % g/cap/day SD

Plastic bottles for beverage 0.54 0.09 0.26

Plastic bottles for food 0.65 0.11 0.30

Plastic bottles for non-food/ 2.72 0.47 0.82

beverage

PET bottles for beverage 3.18 0.55 1.05PET bottles for food 3.16 0.55 0.68

PET bottles for non-food/ 0.28 0.05 0.16

beverage

Foam tray 0.98 0.17 0.24

Other tray 0.58 0.10 0.23

Plastic containers for food 2.09 0.36 0.70

Plastic containers for 1.45 0.25 0.98

non-food

Plastic tubes for food 0.28 0.05 0.25

Plastic tubes for non-food 1.11 0.19 0.34

Plastic packaging for food 8.92 1.54 1.38

Plastic packaging for 5.22 0.90 1.88non-food

Plastic packaging for 13.23 2.28 1.75

unspecified purpose

Plastic shopping bags 45.72 7.89 6.85

Buffer materials 0.51 0.09 0.31

Plastic rope 0.32 0.06 0.43

Other containers and 3.67 0.63 0.49

packaging

Durable products 3.72 0.64 1.26

(multi-use)

Consumable products 1.48 0.26 0.33

(single-use)

Other plastics 0.16 0.03 0.10

Total 100 17.24 11.01

as above-mentioned (Section Organization of

samples) were chosen for participation in the

waste generation survey.

Regarding the waste generation survey, a

short training about survey procedure, waste

separation, explanation, certain rules for waste

collecting, classifying, and quantifying to each

households members was carried out. The waste

generation survey was conducted to acquire data

on the composition and discharge amount of

waste generated from the households for 30 days

from February to March 2009. To make sure that

the households members could follow and cover

the survey proceeding, a 3-day pre-survey was

performed before the 30-day main survey.

The target households were provided with col-

ored transparent plastic bags of two kinds for

waste disposal. Households were requested to

keep and separate their waste into biodegrad-

able wastes and non-biodegradable wastes.

Biodegradable wastes and non-biodegradable

wastes were collected, respectively, every day andevery week.

Regarding waste quantification, biodegradable

wastes were sorted and weighed at the house-

holds house. Meanwhile, non-biodegradable

wastes were sorted into appropriated items of

classification categories and weighed in the labo-

ratory. The weights were recorded as wet weight

with a digital scale measuring a minimum of

1 gram (g).

Furthermore, a questionnaire survey was con-

ducted with a face-to-face interview at householdsto obtain data reflecting demographic character-

istic, socio-economic information, habits of recy-

clable waste discharge, and household attitude.

A questionnaire survey of recyclable-junk buyers

and recycling depots was also conducted to collect

information about transaction price and recycling

potential of recyclable waste.

Analytical procedure

The authors calculated key statistics related to

plastic waste generation rates by subcategory. The

authors also assessed correlations between the

plastic waste generation rates of each subcategory,

in addition to relevant factors such as household

size, and income levels using ANOVA and rank

correlation analysis. Software (SPSS ver. 15.0;

SPSS Inc.) was applied for statistical analyses.

Results and discussion

Household waste generation and composition

The average and standard deviation of the HSW

generation rate by physical category are shown in

Table1.

The average of total HSW generation in CTC

was 281.27 g/cap/day for an average of 4.52 res-

idents per household. This generation rate was

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Environ Monit Assess (2011) 175:2335 27

similar to the study result of Sujauddin et al.

(2007) in Chittagong, Bangladesh with the gener-

ation rate of 250 g/cap/day; although it was lower

than in the south and west Asian cities with the

generation rate of 500 to 800 g/cap/day (Interna-

tional Environmental Technology Center1996).

Regarding the compostable potential of HSWin CTC, the result showed that compostable

waste constituted a significant fraction of the total

(227.09 g/cap/day, 80.74 %; a total of compostable

food waste and garden waste excluding hard

bones/shells). In comparison to the biodegradable

generation rate in HSW of other cities of devel-

oping countries, the generation rate of biodegrad-

able waste found in this study was little higher

than others, such as 156.5 g/cap/day in Beijing,

China (Qu et al.2009) and 137.5 g/cap/day in Cap

Haitain, Haiti (Philippe and Culot 2009). How-ever, this result was little similar to 224.4 g/cap/day

in Siem Reap, Cambodia (Parizeau et al.2006).

The huge generation rate of food waste was

partly because households had a habit of cooking

their own meals at breakfast, lunch, and dinner

every day. The results of the questionnaire sur-

vey showed that the households members have

a habit of taking their meal at home, as 59.4%,

81.3%, 86.2%, and 15.2%, respectively, for break-

fast, lunch, dinner, and supper. And, another pos-

sible reason may be, Vietnamese people preferfood that is unprocessed and un-packaged. It is

suggested that composting is a potential option

for promoting waste reduction and recycling of

biodegradable waste generated from households.

The results showed that HSW in CTC also

contained a large share of recyclable waste-

approximately 11%. The results showed that the

plastic fraction appropriated for the most part

of total recyclable waste (approximately 50%),

followed by paper, whereas metals and glass ac-

counted for low share of recyclable waste.

Plastic generation and contribution

Table 1 shows that the average generation rate

of the household plastic waste in CTC was

17.24 g/cap/day. Regarding the composition distri-

bution of plastic waste illustrated in Fig. 2, it is

apparent that plastic packaging and plastic con-

Plastic bottles3.92%

PET bottles6.62%

Plasticcontainers

3.55%

Plastic packaging

73.09%

Other containersand packaging

7.46%

Durableproducts

3.72%

Single-useproducts

1.48%

Other plastics

0.16%

Fig. 2 Composition distribution of plastic waste

tainers were the most numerous plastics gener-ated, accounting for a high percentage (95.64%);

plastic packaging especially appropriated for the

most share of plastic waste (73.09%). The re-

maining consisted of plastic products with 5.20%

(including single-use products, 1.48%) and plastic

miscellaneous (0.16%).

For estimating the major component of plastic

waste generation in CTC, plastic packaging and

bags were chosen as the prior estimation. In this

study, plastic packaging was defined in many kinds

of plastic bags; (1) manufacturers plastic bagswhich enclose the products from the manufactur-

ers (in this study, it includes (a) plastic packaging

for food or beverage and (b) plastic packaging for

non-food and non-beverage); (2) plastic shopping

bags that are used very popularly in Vietnam,

given free of charge while purchasing at supermar-

kets, normal markets, self-owned shops, vendors,

etc.; and (3) plastic packaging for general purpose

which used to contain the goods or products that

are unprocessed or un-packagedthe distributors

or retailers distribute these goods and products

into smaller portions from the large containers or

packaging of the manufacturers by smaller plastic

packaging for easy retail.

The distribution of plastic waste by subcat-

egories in plastic fraction and total waste, re-

spectively, are presented in Table 2 and Fig. 3.

This shows the overview of discharge flow, de-

tailed composition of plastic waste based on types,

purposes, functions, compostable, and recyclable

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Fig. 3 Outline of plasticwaste distribution in CTC

[6.13]Plastic

[0.319] Products[0.228]Durable

[0.091]Single-use

[5.80]Containers

[0.095]Trays

[0.085] Tubes

[0.010]Other

[0.217]Containers

[0.646] Bottles

[0.406]PET

[0.240]Plastic

[4.442]Packaging

[0.195]Beverage

[0.194] Food

[0.017]Non-food

[0.033]Beverage

[0.040]Food

[0.167] Non-food

[0.128]Food

[0.089]Non-food

[0.547]Food

[0.320]Non-food

[0.811]Unspecified-purpose

[2.764]Shopping bags

[0.315] Other

[ ]: Percentage of item in total HSW generated

characteristics. The data are also expected to be

useful for decision makers, researchers, manu-

facturers, consumers, and recycling companies to

develop the 3Rs (reduce, reuse, and recycle) pro-motion program for the largest recyclable source,

plastic waste. Table2 shows that plastic shopping

bags appropriated for almost half of the total plas-

tic waste, approximately 45.72%; following the

plastic packaging group, such as plastic packaging

for general purpose (13.23%), plastic packaging

for food (8.92%), and plastic packaging for non-

food (5.22%). Whereas other subcategories ac-

counted for a very low percentage (each subcat-

egory appropriated less than 4%).

Through the findings from the survey, it isidentified that plastic packaging and bags are

the major component of plastic waste genera-

tion, especially plastic shopping bags. The results

showed that the average generation rate of plastic

shopping bags was 7.89 g/cap/day and the aver-

age numbers of plastic bags generated as 1.05

pieces/cap/day. The density of this item was also

light, 7.43 g/piece of bag. This situation has issued

a challenge for the MSW management related to

collection, treatment, and disposal alternatives of

plastic packaging and bags due to huge numbersand few densities.

Relevant factors on plastic waste generation

Various authors have pointed out that some

socio-economic and demographic characteristics

of households affected waste generation rates of

total and its compositions (Dennison et al. 1996a,

b, Gomez et al. 2008, Bandara et al. 2007, and

Qu et al. 2009). In this study, the authors also

analyzed the correlations between plastic waste

generation rates by subcategory and factors such

as household size and income level.

Household size

Plastic HSW generation rate (in g/cap/day) of

subcategories by household size was presented in

Table3.The average rate of smallest household

size category, two residents per household, was

the highest (25.17 g/cap/day), and the rate got

lower as the household size got larger.

Table 3 also showed the results of ANOVA

analysis and rank correlation analysis by thehousehold size. The result of ANOVA analysis

indicated that significant average differences were

found on plastic bottle for food/beverage (p 1,500001

0.27

0.510.550

.851.36

1.760.09

0.250.53

0.690.45

0.852.32

2.951.83

3.293.2

2.5

4

10.38

6.861.32

0.711.08

1.97

0.39

0.4724.5

13.9

ANOVA:

1.59

0.08

0.89

0.89

1.02

0.58

2.72

3.29

2.85

1.35

1.14

1.22

1.78

3.67

Fvalue

Correlation

0.0

5

0.04

0.04

0.09

0.03

0.0

3

0.11

0.21

0.05

0.08

0.05

0.07

0.05

0.15

coefficienta

aRankcorrelationanalysisbyKendallstau-b

p

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