Pertanika 11(1),151-155 (1988)

COMMUNICATION IV

Analysis of Floating Refuse along the Gombak River

ABSTRAK

Data jenis-jenis dan berat sampah terapung di Sungai Combak, dekat Jalan Sentul di Kuala Lum­pur pada suatu jangka masa 6 bulan telah dikumpulkan. Berdasarkan sampel-sampel yang telah diambil,sampah dibahagikan kepada kategori-kategori yang berlainan, dan kadar berat serta ketumpatan puratapukalnya telah didapati. Kadaran terbesar berat (42%) sampah itu terdiri daripada tin-tin, kontena­kontena dan benda-benda lain-lain yang perbuat daripada logam. Ketumpatan purata pukal bagi sampahbasah adalah lebih kurang 100 kg/m 3. Cadangan-cadangan juga diutarakan berkenaan dengan kaedah­kaedah yang sesuai, untuk mengumpul sampah terapung, dan membersihkan sungai-sungai di sekitarBandaraya Kuala Lumpur, berdasarkan kepada ciri-ciri sampah dan penilaian dibuat terhadap kaedah­kaedah yang sedang diuji pada masa kini.

ABSTRACT

Data were collected on the types and weights offloating refuse along the Combak River offJalanSentul in Kuala Lumpur over a period of 6 months. Based on the samples taken, the refuse was dividedinto different categories and their proportions by weight and average bulk density were estimated. It wasfound that the largest component by weight (42%) of the refuse consisted of cans, containers and otherproducts made from metal. The average bulk density of the wet refuse was about 100 kg/m 3 . Suggestionsare also made with regards to the best methods to collect the floating refuse and to clean up the riversin the Kuala Lumpur City area based on the characteristics of the waste and an assessment of the variousmethods being cu"ently tested.

INTRODUCTION

The problem of river pollution and efforts to cleanup have recently been given a lot of attention. Oneof the major causes of river pollution is the refusethrown into the rivers by people and industries.According to a newspaper report (Malay Mail,1986), as much as 55 m3 of rubbish was collectedin the Klang river daily by a newly installed me­

chanical "witch". More than $25 million (NewStraits Time, 1985) was reported to have beenallocated by the Federal and Selangor Govern­ments between 1980 and 1983 to dredge riverbedsand clean rivers in this country.

As a first step towards solving the problem, astudy was conducted on the Gombak river inKuala Lumpur. The objectives of this study wereto determine the characteristics and bulk densityof floating refuse and to propose a solution forcollection and disposal of the refuse. The studywas done at the site where an experimental float-

ing lock boom was installed by Jabatan Parit danTaliair as part of the cleansing efforts on riversflowing into the city. The floating lock boom wasmade from empty drums strung together acrossthe river and anchored to both banks. The boomfloats with the rise and fall of the water levelIPlate IJ.

iA.~~

Plate 1: The floating lock boom installed acrossthe Combak River to trap floating garbage.

YONG EU FAN AND TAN l<A KHENG

In addition to being an aesthetic problem thefloating refuse also poses a potential health hazardespecially to communities downstream which de­pend on the river for their daily chores. It mayalso contribute to floods due to the impedimentof flow along the river course. This study looks atthe types and characteristics of floating refuse thatwas trapped at the floating boom installed at theGombak river. An assessment is also made to exa­mine various methods currently employed to cleanup rivers in the City areas.

MATERIALS AND METHODS

Data were collected over a period of 6 monthsfrom August 1986 to January 1987 at the site ofthe Gombak River off Jalan Sentul in Kuala Lum­pur. The catchment area is about 122 km 2 withthe maximum length of catchment at 23km andthe maximum breadth being 8km. The source ofthe Gombak River is Gunung Bunga Buah in theGenting Highlands area. The topography consistsof steep mountainous country rising to heights of1220 m for about 60% of the catchment and theremainder is hilly undulating land.

Most of the mountainous areas are undervirgin jungle while the hilly areas are mostly underrubber cultivation. The small low-lying areas areunder padi cultivation and tin mining. All alongthe Gombak River upstream of the study site,there are numerous villages, squatter settlements,housing estates, high rise flats and some factories.A hike taken along the river bank revealed muchrubbish along the river banks thrown from houses[Plate 2j. There were also some wooden houses

under construction and small backyard factorieswhich may account for the numerous wooden

Plate 2: Rubbish along the Gombak River Banks.

planks intercepted at the boom. At a few places,sewage from buildings and factories was dischargeddirectly into the Gombak River.

Floating refuse was trapped by a floatingboom tied across the width of the river, whichwas built by labatan Parit dan Taliair Selangor onan experimental basis. The refuse was retrievedand collected by a team of workers from city Hallon a daily basis [Plate 3j. The refuse collectedwas then hauled away by a truck to a disposalsite [Plate 4]. The capacity of the truck wasabout 10.8 m3

.

Plate 3: City hall workers collecting garbagetrapped by the floating boom.

Plate 4: Garbage being loaded into trucks fordisposal after sorting out the bottles,plastic, tins etc.

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ANALYSIS OF FLOATING REFUSE ALONG THE GOMBAK RIVER

RESULTS AND DISCUSSION

In" an attempt to characterize and classify therefuse. the following major categories were identi­

fied:

The refuse was weighed in a bamboo basketof 110,880 cm3 capacity on a weighing balancewith an accuracy up to 25 gm. The bulk densityof the wet refuse was obtained from the weightand volume readings. All readings were taken ona wet weight basis. The refuse collected wasdivided into different types and their characteris­tics and proportions by weight were evaluated. Atotal of 12 sample readings were abstracted fromthe data for further analysis. The average bulk density of the refuse was

found to be about 100 kg/m3 with a standarddeviation of 30. About 42% of the refuse wasfound to be from the metal category whichformed the largest proportion by weight of cons­tituents. Next carne household refuse (18.6%)followed by plastic products (18.4%). The re­mainder consisted of glass (10.3%), miscellaneousitems (4.3%), paper (4.0%) and rubber (2.5%) indecreasing order as shown in Table 1.

In addition to the above types of floating re­fuse, a large proportion of the material trapped bythe floating boom consisted of pieces of wood,logs and tree branches of various sizes. Duringperiods of heavy rain, large pieces of timber and

products made of rubber e.g.slippers, shoes etc.

cardboard boxes andcontainers.

includes polystyrene, rattan,cloth, tree branches and othermaterials not classified above.

(vi) Paper

(v) Rubber

(vii) Misceila­neous

bottles and containers.

household waste tied in plasticbags.

tin cans, containers and othermetallic products.

bottles etc.

(i) Metal

(ii) Glass

(iii) Plastic

(iv) HouseholdRefuse

TABLE 1Composition of floating refuse taken from Sungai Gombak, Kuala Lumpur.

CONSTITUENTS %ByWeight

Constituents Gombak Kuala [1) Petaling [2)River Lumpur Jaya

Metal 41.8 5 5.9

Household garbage 18.6 51·· 48.3

Plastic 18.4 8 9.4

Glass 10.3 3 4.0

Paper ·4.0 28 23.6

Rubber 2.5

Miscellaneous 4.3 5··· 8.8

Bulk Density100 • 286 172

(kg/m 3)

Notes: (1) Department of Environment's Survey, 1978

[2) Petaling J aya Solid Waste Management Study Report 1985.

• Total of 12 samples analyzed and results based on wet weight basis

.. Food waste (garbage)

••• Wood and Textiles

PERTANIKA VOL. 11 NO.1, 1988 153

YONG EU FAN AND TAN KA KHENG

logs floated down the river. On average, a normalday's composition did not contain a significantamount of logs and owing to the difficulty inquantifying them, these were not included in theabove categories of refuse.

It was observed that the weight of refusethat floated down the river and got trapped inthe boom showed a positive correlation withvelocity and discharge of the river. This is tobe expected as heavy rain and the subsequentswift flowing waters would dislod~e a log of therefuse that got trapped along the bottom andriver banks. The amount of refuse includinglogs and tree branches that were collected dailyvaried from less than I truck load to a maximumof 3 truck-loads per day. This means that duringrainy days, as much as 30 m3 of refuse getstrapped in the boom daily.

It was found that the floating boom shownin Plate 1 was not effective in trapping refuseduring extremely low and high flows. Under theseconditions a lot of refuse either got sucked underor flowed over the top of the boom. The floatingboom also overturned and failed at one pointduring the investigation due to exceptionallyheavy rain and the swollen state of the river. Oneof the reasons for its failure was inadequate slackprovided at both ends of the boom resulting in itnot being able to rise and fall with the water level.

In Malaysia, it has been estimated that the percapita waste generation rate is in the region of0.5 kg/person/day (Pillay & Tan Hoo, 1985).Surveys were carried out by the Department ofEnvironment (DOE) in major towns in Malaysiaand some basic information on the quality and the.characteristics of solid waste generated fromdomestic and commercial areas of urban centresare shown in Table 1. Comparing the characteris-

. tics of the samples of floating refuse collected andthe results of the DOE survey, it is seen that thegreatest difference was found in the categories ofmetal and paper. The greater percentage of papercollected from the DOE survey is probably attribu­table to the fact that the solid wastes were col­lected from commercial and industrial sources inaddition to residential areas whereas the floatingrefuse was mainly from domestic sources. Thelarge percentage of metal items collected (42%)from the Sungai Gombak compared with the solidwastes collected from Kuala Lumpur (5%) could

simply be due to the fact that the people livingalong the Sungai Gombak are using the river as Il

convenient dumping ground for used tin cans,metal containers and other household junk. Inaddition the bulk density of the wet floatingrefuse was found to be much less than that of themunicipal solid wastes taken from the DOEsurvey. It is expected because only the less densematerials would be carried down by the river

while the heavier ones would sink to the bottomand remain there.

CONCLUSION

I. The present methods 'employed to clean upthe rivers in the Kuala Lumpur city area in­cludes floating booms, nets, a mechanicalfloating "witch" and thrash screens made ofconcrete and iron grilles to trap the refuse.All the above methods require the stationingof 1 to 4 persons to dispose the refuse thatis collected. If appears that a fully me­chanized and efficient collection systemwould be too uneconomical and difficult toimplement and not likely to be able to handlethe occasional huge logs and branches thatfloat down the river. Any successful systemwould probably have to be a combination ofhuman manpower, nets, booms and mecha­nical rakers in series in order to handle all thedifferent types of refuse found.

2. On the whole, most of the floating refusewere from domestic wastes and a minimalamount of industrial/trade wastes were found.This suggests that efforts to clean up riverswould be futile without comprehensive publiceducation campaigns and most importantly,the provision of adequate disposal and collec­tion facilities for the solid wastes generatedby squatters and those living along the riverbanks.

3. A comprehensive strategy and plan of actionneed to be formulated to clean up the riversin the City area and to restore them to a rea­sonably clean condition so that they are envi­ronmentally and aesthetically pleasant enoughto be used for recreation purposes by the

public. If this is not done, it will not onlyresult in an increased burden to the nation inthe future but also in increased invisible costs

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ANALYSIS OF FLOATING REFUSE ALONG THE GOMBAK RIVER

related to disease and other environmentalproblems.

ACKNOWLEDG EMENTS

We appreciate the effort put in by our researchassistant Frank Yang Siew Kee in carrying outthe data collection and analysis.

YONG ED FANTA KA KHENG

Depts. ofCivil & Environmental Engineering,Facultry ofEngineering,Universiti Pertanian Malaysia43400 Serdang, Selangor, Malaysia.

REFERENCES

Malay Mail, "A Crying Shame", Pg. 4-5. 28 June. 1986ew Straits Times, "Development takes heavy toll on

Klang River", 11/2/85.Pillay, S. & Tan Hoo (1985): Solid Waste and Toxic and

Hazardous Waste Management. Paper presented atSeminar Keadaan KuaJiti ,'\lam Sekeliling. 8 - 11July 1985. APDC, Kuala Lumpur.

(Received 21 April, 1987)

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