municipal solid waste generation, composition, and management in the douala municipality, cameroon

Municipal Solid Waste Generation,Composition, and Management in the Douala Municipality, Cameroon

JEWM

Municipal solid waste generation, composition, and management in the Douala municipality, Cameroon

1*Innocent Ndoh Mbue, 1Bitondo D, 2Balgah Roland Azibo 1The University of Douala, Faculty of Industrial Engineering, department of Hygiene, Safety and Industrial security, P.O.

Box 2071 Douala, Cameroon 2 Research Fellow/Lecturer, College of Technology, University of Bamenda, P.O. Box 39, Bambili

The study evaluates municipal solid waste generation, composition, and management in the Douala municipality of Cameroon at landfill level. Load count analysis was used for the systematic assessment of the flows and stocks of materials within the landfill in space and time. Descriptive and inferential statistics methods were used to draw conclusions. The results show that, on average, municipal solid waste composition in the municipality has been changing over time. On average 490194580 Kg of wastes are generated per month, giving a per capita generation rate of 0.54 ± 0.071 kg person

-1month

-1. While inert (7.4±0.8), metal (2.6 ± 0.8), glass

(3.5% ± 1.3), and paper (14.5% ± 0.9) wastes (2.0% ± 0.1) had higher proportions in the dry season, plastic (16.1% ± 2.6), organic (49.8.3% ± 3.1) and special wastes (2.0% ± 0.1) had higher proportions in the rainy season. However, at α = 0.05, all waste categories resulted in P > α, with extreme critical values for the test statistic t, suggesting that waste composition do not significantly differ from season to season. Similar results were observed for the mean

generation rates across the different districts 𝐱𝟐 𝟒,𝟎.𝟎𝟓 = 𝟗. 𝟒𝟖𝟕𝟕; 𝐏 = 𝟎. 𝟏𝟓 .Forecasting

generation rates could be important for proper planning of operations related to solid waste management.

Keywords: Municipal solid waste, Douala municipality, Cameroon, Material flow analysis, Load count analysis, Per capita generation rate. INTRODUCTION Increasing population levels, booming economy, rapid urbanization and the rise in community living standards have greatly accelerated the municipal solid waste (MSW) generation rate in developing countries (Minghua et al., 2009).In African cities poor management of solid waste is a common phenomenon due to budgetary problems, mismatching plans and inadequate information about the amount of solid waste generated by residents (Simelane and Mohee, 2012). At the same time, improper handling and disposal of solid waste constitutes a serious problem: it results in deterioration of the urban environment in the form of air, water, and land pollution (Adekunle et al., 2011; Jalil, 2010) that pose risks to

human health, and cause serious environmental problems (Khajuria et al., 2008). The environment has a limited capacity for waste assimilation. If too much waste enters the environment rather than being recycled or reused, the assimilative capacity of the environment is put under too much stress to be able to handle the total quantity of waste generated.

*Corresponding author: Ndoh Mbue Innocent, The University of Douala, Faculty of Industrial Engineering, department of Hygiene, Safety and Industrial security, P.O. Box 2071 Douala, Cameroon, Email: [email protected]

Journal of Environment and Waste Management Vol. 2(4), pp. 091-101, October, 2015. © www.premierpublishers.org, ISSN: 1936-8798x

Review

mailto:[email protected]


Mbue et al. 091 The challenge, therefore, for the municipal environmental engineers and planners is to employ green technology approaches that are viable and sustainable. Solid waste composition, generation and management seem to be important to city authorities to help them in policy making and proper planning of operations related to solid waste management. In the past decades, a large number of research studies have been undertaken to determine influential factors affecting waste management. A variety of approaches have been adopted for assembling detailed quantitative data on the amount, location, and characteristics of a waste stream (Felder et al., 2001;Mason et al., 2003; Dahlen et al., 2007). Several other studies have focused on waste characterization at the household level (e.g. Chang and Davila, 2008; Gomez et al., 2009). A few other studies have attempted to develop either a systematic approach for MSW at both the household and non-household level (Zotos et al. 2009), or identified factors influencing the elements of the waste management systems (Akinci et al., 2012; Al-Jarallah and Aleisa, 2013).Some researchers have documented how an adequate legal framework contributes positively to the development of an integrated solid waste management system (Asase et al., 2009) while the absence of satisfactory policies (Turan et al. 2009, Mrayyan and Hamdi, 2006) and weak regulations (Seng et al., 2010) are detrimental to it. While numerous waste characterization studies have been conducted at the household level (Chowdhury, 2009; Gomez et al., 2009) only a small number exist for the municipal sector (Hristovski et al., 2007, Zhuang et al., 2008). In the same way that municipal waste characterization studies provide local decision makers with a detailed understanding of a waste stream and enable waste management programs to be tailored to local needs (Chang and Davila, 2008), waste characterization studies at municipal level identify urban specific and regionally relevant opportunities for waste reduction and recycling, representing an essential step towards greening the community. Such data is key to long term planning for the management of solid waste in an efficient and economical manner (Gidarakos et al 2006), and for the identification of waste components to target for source reduction, recycling, design of material recovery facilities and waste-to-energy projects (del C Espinosa Llorens et al., 2008; Qu et al., 2009). The anthology of MSW study throughout the world is scant. In developing economies the data on MSW generation have a short history and insufficient national data or data of a large urban or periurban population center (Shekdar, 2009). In Africa, waste characterization data specific to African cities is generally not available (ADB, 2002), the composition of the waste varies depending upon such diverse variables as urbanization,

commercial enterprises, manufacturing, and service sector activities. In Cameroon, MSW management including control, collection, processing, utilization, and disposal, is the responsibility of the municipalities. Waste management policy is based on a public-private partnership which ensures regular collection and processing service for domestic waste in the major cities. However, data on MSW generation, composition and management have insufficient national data or data of a large urban or peri-urban population Centre. Policy decisions that influence the components of MSW systems are not possible until data of composition and quantity of solid waste are available. This view is shared by Acurio et al (1997) who contend that the type of decision making that leads to adequate solid waste management should be based on sound understanding of composition. This study will attempt to fill this knowledge gap in order to make theoretical and empirical contribution in the field of waste management in the country. The purpose of this study is therefore to determine the generation rate and composition of municipal solid waste with the intention of providing base line data for development of municipal solid waste management system in the Douala municipality of Cameroon. Key research questions are:

What is the generation rate and composition of municipal solid waste in the Douala municipality? How have MSW in the Douala Municipality varied in generation and composition over the past decade (2003 to 2013?) What technically and administratively feasible waste management improvements and strategies should be adopted to advance the sustainability of the current system?

The approach consists in manually segregating the wastes on site. Load count analysis of all collected samples was done on site. Mean values and standard deviations were calculated for different components of MSW. MATERIALS AND METHODS Study Area The city of Douala (210 km

2 /80 sq mi) is the capital of

the Littoral region of Cameroon. It is Cameroon’s economic capital, the richest city in the whole CEMAC region of six countries, located on the banks of the Wouri River, at 4°02′53″ N Latitude 9°42′15″E Longitude, situated in the Wouri division at an average elevation of 13m above sea level. Five urban municipalities (also known as districts) and one rural municipality form the urban community of Douala: the town districts of Douala I whose headquarters is at Bonanjo, Douala II whose


J. Environ. Waste Manag. 092 headquarters is New Bell, Douala III whose headquarters is at Logbaba, Douala IV whose headquarters is at Bonassama, Douala V whose headquarters is at Kotto, and Douala VI whose headquarters is at Manoka (Fig.1).

Figure 1. Map of Africa and Cameroon showing the city of Douala with its municipalities; “a-f”: CEMAC countries

Together, the six local governments are commonly referred to as the Douala Urban Council (DUC). Douala is also an industrial city and one of the fastest developing urban areas in Africa and ranks first at national level. Politically, the 2005 population censures estimate the population to a controversial figure of 1.907 million (UNdata, 2013). However, according to current estimates from the Douala urban council, the population of the municipality is estimated to at 5,000,000 people with an average growth rate of 4.8%. Research design and Data collection Both exploratory and descriptive research designs were employed to achieve the objectives of this study. The following data-collection phases were employed:

Review of existing literature; Quantifying the waste stream through vehicle surveys; and Determining the composition of the waste stream through sampling and sorting.

Review of existing literature began with an evaluation of internal policies and procedures related to municipal sustainability and waste management, external documents including government regulations and guidelines and various municipal waste composition studies. Through their annual solid waste reports, HYSACAM office provided historic data on quantities of waste generated daily, weekly, monthly and yearly. Commercial recyclers and end-users provided information on the types and estimated quantities of wastes recycled in a voluntary survey. Background research Its aim was the identification of the functional elements existing within the management of MSW in the

municipality, and of the most relevant stakeholders. It included visits to the e landfill at PK 18 (landfill site). Field research Field work was conducted to identify the solid waste sources, generation and composition. The aim of this step was to improve the quality of the data gathered during the background research. The samples were collected from the landfill for both dry and rainy seasons. The main tools used in data collection were interviews sheets and scale balance. In order to obtain a higher accuracy in the generation rates, historic data from the facility and daily data on the waste load weights collected by the trucks of the municipality were used. Waste sampling Sample collection and segregation was done monthly from January 2013 to December 2013 to explore seasonal variations and representative characteristics of MSW. The sampling locations at the landfill site were identified in consultation with HYSACAM authorities responsible for the operation of the site to obtain a representative sample (Fig. 2).

Figure 2. Sampling stations of MSW at PK10 landfill

Load count Analyses (Tchobanoglous et al., 1993b) was used to estimate solid wastes quantities generated and collected. Vehicles entering the landfill were surveyed using survey forms. Loaded trucks carrying waste to the landfill are first weighed, their size and destinations identified before off-loading takes place. To choose the waste collection trucks, several truck drivers were asked from which route/district the waste was being collected. Waste was sampled from numerous districts (strata): Douala I, Douala II, Douala III, Douala IV and Douala V, to develop a waste composition profile for each stratum. The strata were then “added together” in a way that reflects each stratum’s relative contribution to the overall waste stream, thus producing overall waste composition information. Samples were collected at 10 days of intervals from 03 February to 31

st of December 2013. The

apparatus used was a Single Pan, Physical


Mbue et al. 093 Table 1. Waste composition category

ID Waste composition category Waste components

1 Paper Packaging paper, cardboard, wrapper, newsprint, magazines, office paper

2 Plastic

PETE Containers, HDPE Containers, Miscellaneous Plastic Containers Plastic Trash Bags, Plastic Grocery and other Merchandise Bags, Durable Plastic Items, Remainder/Composite Plastic

3 Glass Clear, brown, green, other

4 Metal Ferrous, non-ferrous, tin cans, metal foils, Other Non-Ferrous and ferrous metals

3 Electronics

Computer-related Electronics, Other Small Consumer Electronics, Video Display Devices, radio

4 Household Hazardous

Paint, Vehicle & Equipment Fluids , Used Oil, Batteries, Remainder/Composite Household Hazardous

5 Other Organics

Food wastes, Leaves and Grass, Prunings and Trimmings, Branches and Stumps, Manures, Carpet, Textiles (rubber, clothes, synthetic, cables, leather), Remainder/Composite Organic

6 Inerts& other

Concrete, Asphalt Paving, Lumber, Gypsum Board, Rock, Soil, and Fines, Remainder/Composite

7 Special Waste Ash, Bulky Items, Tyres, Treated Medical Waste, Remainder/Composite Special Waste

balance. The Parameters studied are composition and generation rate of municipal solid waste. Each load was separated manually by component example - wood, concrete, plastic, metal, etc. Each component is weighed and weights recorded. Assessing waste quantity and composition in this way has been shown to capture the high spatial variation of waste (Felder et al., 2001), thereby yielding more reliable and representative data. Waste Sorting and Processing of Samples A sorting & characterization form was used. Surveys were conducted on the same days that waste was sampled. Sorting and processing of waste samples were manually done with the help of landfill workers into seven categories, namely paper, plastic, electronic, household hazardous wastes (HHW), other organics, inerts and others, and special waste (Table 1). Data Analyses The analysis of the data was carried out qualitatively and quantitatively. Flows were expressed in kg/year or in kg/capita/year. Mean values and standard deviations were calculated for different components of MSW. The weight-based percentage composition for each subcategory(primary and secondary) was calculated. Estimating the composition of MSW Composition estimates represent the ratio of the components’ weight to the total waste for each noted

material component in a particular segment of the waste stream. For a given material, j, in all of the relevant samples, i, the ratio, rj, of the material weight, m, to the total sample weight, w was estimated (Equation 1) from each stratum or subdivision:

𝑟𝑗 = 𝑚 𝑖𝑗𝑖

𝑤𝑖𝑖(1)

for i = 1 to n, where n = number of selected samples; and for j = 1 to m, where m = number of components. Estimating the Error Range The confidence interval for this estimate was derived in two steps. First, the variance around the estimate was calculated, accounting for the fact that the ratio included two random variables (the component and total sample weights). The variance of the ratio estimator equation follows (William, 77):

𝑉𝑟𝑗 ≈ 1

𝑛

1

𝑤 2 𝑐𝑖𝑗 −𝑟𝑗𝑤𝑖𝑖

𝑛−1

2

(2)

Where:

𝑤 = 𝑤𝑖𝑖

𝑛

Second, precision levels at the 90percent confidence level were calculated for a component’s mean as follows:

rj ± (z Var(rj) (3)

Where z = value from z-statistics (1.645) corresponding to 90% confidence interval.


J. Environ. Waste Manag. 094

Table 2. Current Solid waste generation in the Douala Municipality

Municipality Amount Generated (Tonnes/day) Amount Collected (Tonnes/day) Collection rate (%)

Douala I 3,423 1845 54

Douala II 3,975 1984 50

Douala III 4,050 2104 52

Douala IV 4200 2245 53

Douala V 4150 2342 56

Total 19,798 10520 53

Calculating the Mean Estimate for Combining Waste Sectors Composition results for strata were then combined using a weighted average method to estimate the composition of larger portions of the waste stream. The relative tonnage associated with each stratum served as the weighting factors. The calculation was performed as follows:

Oj = P1 ∗ rj1 + P2 ∗ rj2 + P2 ∗ rj3 + ⋯(4)

Where: P = the proportion of tonnage contributed by the

noted waste stratum (the weighting factor),where the sum of all the values of p is 1

r = the ratio of component weight to total waste weight in the noted waste stratum (the composition percent for the given material component), and

For j = 1 to m, where m = the number of material components

The variance of the weighted average by taking the variance of equation (4):

V(Oj) =

p21

Var rj1 + p22

Var rj2 + p23

Var rj3 + ⋯ (5)

Estimating the quantities of MSW generated Total waste generated on a daily base was estimated as: Total waste generated = Disposed Waste + Recycled Waste + Diverted Waste (6) = Disposal + (Recycling + Reuse) The proportion of waste diverted was obtained through field interviews and field observations. The weight of waste for each truck entering the landfill equals, the weight of the truck when full of waste minus weight of the truck when empty. From [4], the per capita generation rate was calculated as (equation 5):

Per capita generation =Total waste generated

Population

Kg

day ∗person (7)

Hence,

Generation recycled =MSW Recycled

MSW disposed +MSW recycled∗ 100%(8)

To keep the waste composition tables and figures readable, estimated tonnages are rounded to the nearest ton, and estimated percentages are rounded to the nearest tenth of a percent. Due to this rounding, the tonnages presented, when added together, may not exactly match the subtotals and totals shown. Similarly, the percentages, when added together, may not exactly match the subtotals or totals shown. Percentages less than 0.05% are shown as 0.0 percent. Hypothesis tests were conducted to compare the municipal waste composition among the districts and seasons. RESULTS AND DISCUSSION Generation of Municipal solid waste On average, the municipality of Douala is generating solid waste at a tune of 490194580 tonnes per day in 2013 giving a per capita generation rate 0.54 ± 0.071 kg person

-1month

-1. Of these tonnes 53% is collected and

the remaining 47% are buried, burned, scavenged by informal recyclers or dumped by the road side or into drainage canals (Table 2). These figures in the table shows that serious planning is essential if the municipality will ever be clean and solid waste characterisation and quantification are important aspects of that planning process. The average per capita generation rates were 0.46, 0.51, 0.56, 0.59 and 0.63 kg kg capita

_1month

_1 for Douala I, II,

III, IV and V respectively. The results agree with the range estimated by other recent research findings from other similar cities of the developing countries (Table 3) Though there is a strong positive correlation between population of a district and per capita generation rates (r= .78, p< .05), the variation across municipalities is not significant;

𝑥2 4,0.05 = 9.4877; 𝑝 = 0.15 .


Mbue et al. 095

Table 3. MSW generation in selected major cities from Africa

City-Country Population (Millions)

MSW generation rate (Kg.capita

-1.day

-1)

Author (s) and year

Kumasi-Ghana 1.89 0.48 Asase et al (2009) Abuja-Nigeria 2.5 0.44-0.66 Ogwueleka, 2009 Yaounde-Cameroon 1.72 0.52 Parrot et al (2009) Bamako – Mali 1.5 0.43 Samake et al (2009)

Figure 3. Trend in MSW collection rate in Douala (2003-2012)

Trends in Solid Waste Generation Waste products from the Douala municipality originate from a variety of residential, commercial, institutional, construction and demolition, municipal services, treatment plant sites, industrial and agricultural activities. Regular collection and processing is carried out by HYSACAM. On average, between 50 - 60% of wastes generated by the municipality are collected are collected while about 47% remains uncollected (Fig. 3) One of the reasons for HYSACAM’s success is its ability to adapt to changing requirements. It has recruited trained personnel and deployed modern, well-maintained equipments– key requirements for managing waste in towns and cities with as many as several million. To reach harder-to-access neighbor hoods, HYSACAM has developed pre-collection agreements with community based organisations that gather the waste from the inaccessible areas and transfer it to the company’s collection bins. As a result, it is able to achieve collection rates of over 50% (Parrot et al., 2009). Generally, municipalities have failed to manage solid waste due to financial factors. The huge expenditure needed to provide the service, the absence of financial support, limited resources, the unwillingness of the users to pay for the service (Sujauddin et al., 2008) and lack of proper use of

economic instruments have hampered the delivery of proper waste management services. Sharholy et al. (2008) indicated that the involvement of the private sector is a factor that could improve the efficiency of the system. Composition and Trend in Per Capita Yearly Generation of Solid Waste The physical survey of the landfill site shows that the organic fraction includes paper, cardboard, rubber/leather/synthetics and compostable matter (Fig 4). The average composition of MSW includes Paper and cartons 19.4% ±(4.9), Plastic 15.4%±(1.1), Glass 2.2%±(0.3), Inert 9.4% ±(2.4), Metals 3.2%±(1.3), Other organics (48.4%±(7.2), and Special wastes 2.0% ± (0.6) (Table 4). The generation of municipal solid waste is increasing in the Douala municipality probably due to the increased population density, consumption pattern, life style behavior and economic development etc. Food waste (mixed), paper and card board waste and plastic waste are dominant in the waste stream. The waste stream has higher percentage of organic waste compared to the inorganic. The high amount of organic waste can be effectively used as organic manure through composting where as recycling and energy recovery would be an



Figure 4. An overview of waste composition: overall municipal wide disposed waste

Table 4. Overview of the Douala municipality’s overall disposed waste stream

Material Est. percent + / -

Est. tons Material

Est. percent + / - Est. tons

Paper and Cartons : 19.4%

639646 Plastic 15.4%

441817

PaperBags 1.2% 0.9% 39566 PET containers 5.2% 0.1% 171451

Office Paper 5.2% 0.9% 171451 HDPE containers 2.4% 0.1% 79131

Magazines/catalogue 1.9% 0.9% 62646

Plastic trash bag 0.7% 0.1% 23080

Newspapers 4.3% 0.9% 141777 Misc. containers 4.3% 0.1% 141777

White ledger paper 0.3% 0.4% 9891

Composite Plastic 2.8% 0.7% 92320

Mixed paper 6.5% 0.9% 214314 Other Organics 48.4%

1635382

Glass 2.2%

85726 Food wastes 24.3% 1.9% 807800

Clear glass bottles 1.3% 0.1% 49457 Leaves & grass 3.8% 0.7% 125291

Composite Glass 0.7% 0.1% 23080 Composite organic 3.3% 0.5% 141777

Windows breakings 0.2% 0.1% 13189

Prunings/trimming 2.7% 1.5% 89023

Inert and other 9.4% 0.1% 309931 Branches & stumps 0.6% 0.4% 19783

Rock/soil/concrete/fine 3.2% 0.1% 105509 Manures 0.1% 0.1% 3297

Lumber/Wood 0.4% 2.2% 13189 Carpet 3.2% 2.0% 105509

Composite 5.8% 0.1% 191234 Textiles 10.4% 0.2% 342903

Metals 3.2%

118697 Special wastes 2.0%

65943

Tin/Steel cans 0.3% 0.1% 9891 Ash 0.2% 0.1% 6594

Major Appliances 0.1% 0.1% 3297 Bulky Items 1.0% 0.1% 32971

Used oil Filters 0.1% 0.1% 3297 Tyres/Rubber 0.2% 0.1% 6594

Aluminiumcans 1.3% 0.4% 42863 Sewage Solids 0.4% 0.1% 13189

Other Non-Ferrous 0.2% 0.1% 6594 Industrial Sludge 0.1% 0.1% 3297

Composite metal 1.4% 0.5% 52754 Composite 0.1% 0.1% 3297

Confidence intervals calculated at the 90% confidence level. Percentages for material types may not total 100% due to rounding

appropriate option for the inorganic fraction of the waste stream. Variation of MSW Composition with Time Non-recyclables (inerts, special wastes and others) have

increased from 15% in 2003 to about 40.60% in 2013 (an increase of 25.6%). This could be attributed to the practice of inclusion of the street sweepings, drain silt and construction and demolition waste in MSW. On the other hand, the decrease in recyclables can be attributed to the increase in recycling enterprises in the city over


Mbue et al. 097

Figure 5. Monthly per capital generation of MSW

Table 5. Statistical comparison of the seasonal composition of MSW from 2003-2013

Waste category

Mean (±SD)

Hypothesis

t

p

Confidence Interval

Dry Rainy Ho Ha Lower Upper

Glass 3.42 ±1.26 3.33±1.28 μ =3.4 μ ≠3.4 .027 0.735 -1.78 -1.78 Inerts& Others 2.72 ±.877 3.04±1.5 μ =2.72 μ ≠2.72 -.382 0.172 -2.20 1.56 Metal 2.90 ±.600 2.5±.945 μ =2.90 μ ≠2.90 .781 0.338 -.78 1.61 Paper 14.65 ±.98 14.47±.96 μ =14.65 μ ≠14.65 .294 0.730 -1.19 1.55 Putrescibles 45.0 ±4.0 47.0±1.41 μ =45.0 μ ≠45.0 -.651 0.404 -11.78 7.78 Plastic 16.42±3.1 16.15 ±2.6 μ =16.42 μ ≠16.42 .154 0.715 -3.67 4.20 Special 1.27 ±1.17 2.90 ±2.0 μ =1.27 μ ≠1.27 -1.465 0.287 -4.13 .880

At α = 0.05, the results indicated that all categories resulted in P >α, with extreme critical values for the test statistic t. We thus fail to reject the null hypothesis and conclude that, waste composition do not significantly differ from season to season.

time, which has in turn given rise to the practice of scavenging in the city in general, and at the landfill area in particular, providing employment to hundreds of unskilled workers. The result is a large proportion of compostable and non-recyclable material content both at collection and landfill sites. Thus, if a recycling program for MSW is well conducted, it not only could potentially recover, reuse, and/or regenerate useful resources, but also could reduce the amount of waste to be disposed. Solid waste treatment at source can help to divert over 60% of the total waste and could lead to enormous savings in the cost of waste collection, transport and disposal. To achieve sustainable municipal waste management practices, the challenge will be to reduce the amount of solid waste generated, while increasing the amount of waste diverted from landfills through recycling and other initiatives in an economically feasible way. It is also necessary to realise that economic growth cannot come at the expense of the environment. The importance of understanding the implications for the diversion and recycling of these materials merits an individual discussion on waste treatment in the municipality. Seasonal Variation in MSW The monthly per capita variation of MSW in the municipality showed small fluctuations throughout the

year. There is for example, a noticeable decrease from January to February with a minimum in February, then a sharp rise until the month of March (Fig. 5). This corresponds to the peak of the dry season whereby, putrescibles which constitute over 50% of the waste streams limited in supply. The high generation rates from February to April are related additional wastes resulting from the consumption of drink products in plastic containers (water, fruit juice, dairy products, artificially-flavored drinks, etc.). From April to June, average per capita generation was constant. This corresponds to the rainy season when there is a general drop in food supplies to the city as many food crops are not yet ready for harvest. From July to August, food crops are ready, their supply to the city increase leading to an increase in putrescibles once more and the cycle continues, beginning from October, the start of the next dry season. The rise by year end could be explained by the numerous feasts (Christmas, New Year, other cultural festivals) which traditionally characterize this period each year. On the whole, while inert, metal and glass had higher proportions in the dry season, plastic, organic and special wastes had a significantly higher proportion in rainy season. There was no significant difference in the quantity of wastes generated between the dry and rainy seasons. Table 5 presents the hypothesis test results and confidence intervals.



Figure 6. MSW Recycling Rates, 2003–2013

Municipal Solid Waste Management Practices Solid waste management may be defined as the control of generation, storage, collection, transfer and transport, processing, and disposal of solid wastes in a manner that is accord with the best principles of public health, economics, engineering, conservation, aesthetics, and other environmental considerations, and that is also responsive to public attitudes. The first objective of solid waste management is to remove discarded materials from inhabited places in a timely manner to prevent the spread of diseases, to minimize the likelihood of fires, and to reduce aesthetic insults arising from putrefying organic matter. The Hygiene and Sanitation Company of Cameroon (HYSACAM), established in 1969, is the country’s leading private municipal solid waste management company. Based in Douala and Yaoundé, HYSACAM operates across the entire municipal solid waste management chain, from collection through to processing. It has 5,000 employees and a fleet of 400 vehicles. HYSACAM operates a landfill at PK10, located 10 km away from Douala city center. The landfill is about 25 meters deep and covers a 63 ha area, of which more than 10 ha has been used already (Biotecnogas, 2009). Since 2003 it has been used for disposal of domestic and commercial waste collected in the city at an average rate of 287,000 tons per year. Solid waste management practices in the Douala municipality include: collection, recycling, solid waste disposal on land, biological and other treatments as well as incineration and open burning of waste. The recycling of materials (paper, plastics, metals, and glass) in the Douala municipality is practiced by several small and medium size enterprises. These include SOCAVER for glass; SIPLAST, POLYPLAST, SOFAMAC and SICA for plastic waste, African Recycling Industry, ICRAFON and BOCOM Recycling. COMAGRI and SOCAVER are leaders of glass recycling in the city with an estimated production of 110 tons of glass per day. Metals are sold to industry–

mainly in China and India. Hence, the recycling rate of MSW has risen to about 28% over the past decade (Fig. 6). In moving towards sustainable waste management, the Douala municipality must adopt multiple strategies that target a range of materials and follow the principle waste management hierarchy: first reducing waste at the source, re-using materials when possible and recycling what remains. Should recycling matter go to the recycling industries, this will reduce the burden on landfill and environmental effects as landfill will also be minimized. Although recycling is a definite step towards waste reduction, processing materials for re-use still requires the use of energy and resources (Finnveden and Ekvall, 1998) and recycling alone will not create an environmentally sustainable waste management program (Armijo de Vega et al., 2003). It seems that by targeting specific material categories, the municipality could achieve marked reductions in the amount of waste generated and sent to landfill. An examination of the paper recovered from the municipality waste stream indicates the following sequence of material prevalence: mixed paper → Office papers → Newspapers → Magazines & catalogues. Though targeting paper products in the order of their occurrence could yield the highest rates of waste diversion and reduction, a number of technical and financial complexities may prevent the implementation of this approach. For example, since office paper represents 5.2% of the recyclable material found in the waste stream while magazines and catalogues characterizes only 1.9%, it would be logical to aim source reduction efforts on office papers. Currently there is no alternative. Determining the alternative that would be truly more environmentally friendly choice would require a comprehensive life cycle analysis, which may not be achievable based on available data. Composting is a waste management practice that allows for the transformation of organic waste into a stabilized product. Composting and anaerobic digestion of MSW


Mbue et al. 099 are strategies that are likely to be employed to reduce waste generation and to recycle nutrients. Organic wastes are typically the heaviest component of a waste stream, thereby costing the most money to dispose of, and have the highest potential to emit greenhouse gases, once buried in a landfill (Diaz et al., 1993). The high financial and environmental costs of improperly disposed organic wastes make this component especially important when considering opportunities for increased waste reduction and diversion (Tammemagi, 1999). Diverting organics from the waste stream has proven to be difficult, not only for municipalities but also for the regions in which they are located. Currently, Cameroon lacks a nation-wide strategy for managing compostable organics in the waste stream and as a result, policies for dealing with this material vary significantly among municipalities. For example, composting of green waste is being experimented at the landfill site for the production of organic fertilizers (compost).Unfortunately, the market is dominated by competition from chemical fertilizers. Furthermore, the city is not an agricultural area it is extremely difficult to find individuals who practice composting at home. Incineration is one of the waste treatment technologies that involve the combustion of organic materials and other substances. Incinerator process converts the waste into bottom ash, particulates and heat, which can be used to generate the electric power. In recent years, the concepts of protection and preservation of the environment have gained a prominent place in modern enterprises. Both BOCOM International (Waste Treatment and Incineration Company) and BOCAM (Industrial Waste Management Company) - an ISO 14001 certified companies are leading companies in waste incineration in Cameroon. In partnership with Mobil Oil Cameroon, BOCAM collects used oil from Project work sites, processes the oil at a facility in Douala and sells the treated oil to a nearby cement kiln for use as a fuel. Companies interested in eco-responsible management solutions are signing memoranda of understandings with BOCAM for the treatment of their waste products. If well managed, incineration can be a renewable source of energy. However, the environmental pollution resulting from incineration is a call for concern. Again, incineration significantly reduces, but does not eliminate, the volume of material to be disposed. CONCLUSION AND RECOMMENDATIONS The study was to analyses municipal solid waste generation, composition, and management in the Douala Municipality of Cameroon as a first step towards enhancing the sustainability of the current waste management system. The results presented in this paper emphasize the potential for municipalities to achieve higher rates of waste diversion as well as the challenges

that municipalities may face in the shift towards sustainable MSW management. Paper and paper products, disposable drink containers and compostable organic material represented three of the most significant material types for targeted waste reduction and recycling efforts. Hypothesis tests were conducted to compare the municipal waste composition among seasons and districts and indicated that these had a significant effect on composition. The rainy season had a higher proportion of organic waste, whereas dry season produced higher proportions of, wood, metal, concrete and glass waste. A statistical comparison with a previously published waste characterization data obtained from HYSACAM indicated that the proportions of all waste categories have not changed significantly. These insignificant changes in waste composition indicate that over the past decade, there has been no new trend in population lifestyle, which must be considered when planning future waste treatment scenarios. The following educational and policy techniques are highly emphasized: promulgation of the waste management bill, which will create an enabling environment for enforcement and will provide a legal framework within which environmental impact can be implemented; political motivation (waste management must be seen as a priority at all levels of government); education and awareness (waste management must be taken as a priority among businesses and communities, to encourage waste minimization and recycling to enable acceptance of instruments); development of capacity at all levels of government (for administration, monitoring and enforcement of instruments and of illegal dumping, billing for services to enable cost recovery); increased access to resources for waste management departments (to allow development of capacity, recovery of costs, and improved waste management services); Although the data collection samples in percentile and tonnage are statistically reliable, the idea of collecting data with a higher level of detail within subcategories of dominant waste classes is inevitable. To design an efficient management system, that consider the appropriate final treatment of MSW based on their physical and chemical characteristics, it is important to consider not only information on the generation and composition of MSW but also their physical and chemical characteristics. Therefore, it became necessary for future research to include the physical (humidity, ashes, and specific heat) and chemical characteristics (pH, organic matter and sulfur) of MSW. This information could be very important when considering the design of biogas and other energy plants with wastes as primary products;


J. Environ. Waste Manag. 100 Finally, further analysis on waste trends with respect to household, commercial, and industrial sectors is also necessary. Because organic waste treatment options depend on waste origin, it is important to determine whether the organic waste is pre- or post-consumed and its moisture content. Such information will allow for comparisons between various options, such as composting, biogas production, or utilization as animal feed. However, whether the quantities produced are sufficient for a large-scale waste management system requires further analyses in terms of economies of scale, operating capacities, and break-even analysis. The data presented here will facilitate a thorough compilation and evaluation of the inputs and outputs of such analyses. ACKNOWLEDGMENTS The authors would like to acknowledge the authorities of the Douala municipality and management of the PK10 landfill for their in-kind support. We are also very grateful to the Cameroon government for assisting research in higher education through the modernisation allowance. We show our appreciation to colleagues, friends, municipalities’members and workers that have contributed with valuable information. The authors acknowledged the contributions of Dr. Essam Gooda, Dr. Brahima Kone, Dr. Lorena De Medina Salas, Dr. Ali Hammoud and Dr Mohamed Ben Oumarou for donating their time, critical evaluation, constructive comments, and invaluable assistance toward the improvement of this very manuscript. REFERENCEs Acurio G, Rossin A, Teixeira PF, Zepeda F (1997).

Situation of the municipal solid waste management in Latin America and the Caribbean. Pan American Organisation, Washington, DC, USA BID No.ENV.97-107.

Adekunle IM, Adebola AA, Aderonke KA, Pius OA, Toyin AA (2011). Recycling of organic wastes through composting for land applications: A Nigerian experience.Waste Manag. Res., 29(6): 582-93.

African Development Bank (ADB, 2002). Report Prepared for Sustainable Development and Poverty Reduction Unit: Solid Waste Management Options For Africa. Côte dÍvoire

Akinci G, Guven ED, Gok G (2012). Evaluation of waste management options and resource conservation potentials according to the waste characteristics and household income: a case study in Aegean Region, Turkey. Resour. Conserv. Recycl. 58; 114–124.

Al-Jarallah R, Aleisa E (2013). Investigating causes contributing to increased municipal solid waste in Kuwait: a national survey. J. Eng. Res. 1 (3): 123–143.

Asase M, Yanful EK, Mensah M, Stanford J, Amponsah S (2009). Comparison of municipal solid waste management systems in Canada and Ghana: A case study of the cities of London, Ontario, and Kumasi, Ghana. Waste Manage. 29: 2779.

Biotecnogas report. Douala Landfill gas recovery and flaring project. Version 01 of 4th December; 2009.

Canadian Council of Ministers of the Environment (1996). Waste audit user’s manual: a comprehensive guide to the waste audit process. Winnipeg, MB: Manitoba Statutory Publishing.

Chandrappa R, Das DB (2012). Solid waste management: Principles and practice. Berlin; New York: Springer.

Chang N, Davila E (2008). “Municipal solid waste characterizations and management strategies for the Lower Rio Grande Valley, Texas”, Waste Manage., vol. 28, pp. 776-794.

Dahlén L, Vukicevic S, Meijer JE, Lagerkvist A (2007). Comparison of different collection systems for sorted household waste in Sweden. Waste Manage. (Oxford) 27 (10), 1298–1305.

del C Espinosa Llorens M, Lo´ pez Torres M, Alvarez H et al. (2008) Characterization of municipal solid waste from the main landfills of Havana city. Waste Management 28(10): 2013–2021.

Felder M, Petrell R, Duff S (2001). A solid waste audit and directions for waste reduction at the University of British Columbia, Canada. Waste Manage Res; 19:354–65.

Finnveden G, Ekvall T (1998). Life-cycle assessment as a decision-support tool-the case of recycling versus incineration of paper. Resour Conserv Recy; 24:235–56.

Gidarakos E, Havas G, Ntzamilis P (2006).Municipal solid waste composition determination supporting the integrated solid waste management system in the island of Crete. Waste Manage. 26, 668.

Gόmez G, Meneses M, Ballinas L, Castells F (2009). Seasonal characterization of municipal solid waste (MSW) in the city of Chihuahua, Mexico. Waste Manage. 29, 2018.

Hunger G, Stretz J (2006). Proof of Service: An innovative multifunctional tool for sustainable solid waste management strategies in developing countries. Paper presented at Waste Con 2006, 18th Waste Management Conference and Exhibition, October, Cape Town, South Africa.

Jalil A, (2010). Sustainable development in Malaysia: A case study on household waste management. Sust. Dev., 3(3): 91-102.

Khajuria A, Yamamoto Y, Morioka T (2008). Solid waste management in Asian countries: problems and issues. Proc. of 4th International Conference on Waste management and environment, June, 2-4, 109, 643-653.

Magrinho A, Didelet F, Semiao V (2006). Municipal solid


Mbue et al. 101 waste disposal in Portugal. Waste Manage. (Oxford) 26 (12), 1477–1489.

Mason I, Brooking A, Oberender A, Harford J, Horsley P (2003). Implementation of a zero waste program at a university campus. Resour Conserv Recy; 38: 257–69.

Mrayyan B, Hamdi MR (2006). Management approaches to integrated solid waste in industrialized zones in Jordan: a case of Zarqa City. Journal of Waste Management 26: 195–205.

Ogwueleka TC (2009). Municipal solid waste characteristics and management in Nigeria. Iran J. Environ. Health Sci. Eng., 6(3): 173-180.

Parrot L, Sotamenou J, Dia BK (2009). Municipal solid waste management in Africa: Strategies and livelihoods in Yaoundé, Cameroon. Waste Manage. 29, 986.

Qu XZ, Li XX, Sui Y, Yang L, Chen Y (2009). Survey of Composition and Generation Rate of Household Wastes in Beijing, China. Waste Management 29: 2618-2624.

Samake M, Tang Z, Hlaing W, Wang J (2009). State and management of solid wastes in Mali: Case study of Bamako. Environ. Res. J. 3: 81.

Sharholy M, Ahmad K, Mahmood G, Trivedi RC (2008). Municipal solid waste management in Indian cities.Areview.Journal of Waste Management 28, 459–467.

Simelane T, Mohee R (2012). Future Directions of Municipality Solid Waste Management in Africa.AISAPOLICY-Brief.

Seng B, Kaneko H, Hirayama K, Katayama-Hirayama K, (2010). Municipal solid waste management in Phnom Penh, capital city of Cambodia.Waste Management & Research 29: 491–500.

Tchobanoglous G, Theisen H, Vigil S (1993b) .Integrated Solid Waste Management: Engineering Principles and Management Issues Internatio. In: Clark, J. and B.J. Morris (Eds.), McGraw-Hill, Singapore.

Turan N, Coruh S, Akdemir A, Ergun ON (2009).Municipal solid waste management strategies in Turkey. Waste Manag. 29: 465-469.

Turner R (1995) Waste Management. In: H. Folmer, H. Gabel, and H. Opschoor (eds) Principles of Environmental and Resource Economics, Aldershot: Edward Elgar.

Tammemagi H (1999). The waste crisis: landfills, incinerators and the search for a sustainable future. New York, NY, USA: Oxford University Press.

UNdata (2013). UNSD Demographic Statistics. Available at http://data.un.org/,accessed 15/05/2015

William GC (1997). Sampling Techniques, 3rd Edition.

John Wiley & Sons, Inc.,pp. 115-146

Zotos G, Karagiannidis A, Zampetoglou S, Malamakis A, Antonopoulos IS, Kontogiaani S, Tchobanoglous G (2009). Developing a holistic strategy for integrated waste management within municipal planning: Challenges, policies, solutions and perspectives for

hellenic municipalities in the zero-waste, low-cost direction. Waste Manage., 29(5): 1686-1692.

Accepted 15 September, 2015. Citation: Mbue NI, Bitondo D, Balgah RA (2015). Municipal Solid Waste Generation, Composition, and Management in the Douala Municipality, Cameroon. Journal of Environment and Waste Management 2(3): 091-101.

Copyright: © 2015 Mbue et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

municipal solid waste generation, composition, and management in the douala municipality, cameroon

Education