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Waste Management 26 (2006) 1384–1391

Addressing the operational problems in a composting andrecycling plant

Gurdal Kanat *, Ahmet Demir, Bestamin Ozkaya, M. Sinan Bilgili

Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul, Turkey

Accepted 21 December 2005Available online 3 April 2006

Abstract

The Istanbul composting and recycling plant, constructed in 2001, is one of the few composting plants in Turkey. During test oper-ations of the plant, it was reported that the weight of the oversize materials (OM) above a 80-mm sieve was about 40% of the total incom-ing waste. They mainly consist of plastic bags that were full of garbage, which resulted in operational problems in the plant. In this paper,the composition of OM was determined and evaluated, particularly to find the economic losses in the plant. It was determined thatapproximately 58% of the OM transferred to the landfill area due to operational failures and interruptions could be used at the plantwith improved operational conditions. Otherwise, the plant would realize an annual economic loss of about 640,800 US$. Compost qual-ity in the plant has been satisfactory, but source separated collection, at least the separation of the wet from the dry fraction, is needed toincrease the amount of compost and recovered materials.� 2006 Elsevier Ltd. All rights reserved.

1. Introduction

Solid waste is a significant environmental problem, espe-cially for large cities in developing countries such as Istan-bul city, with a population of around 12 million. Indeveloping countries, some municipal solid waste (MSW)management alternatives, such as source separation, recy-cling and composting, have been applied (Alhumoudet al., 2004; Haque et al., 2000; Chung and Poon, 2001).However, there are still some waste management problemsin these countries (Idris et al., 2004). The main solid wastedisposal method in a number of developing countries,including Turkey, is landfilling or open dumping, mainlydue to its simplicity and low cost. For this reason, few stud-ies of waste characteristics or management alternativeshave been conducted. Moreover, analyses of different sizesof materials rarely have been conducted in developingcountries.

0956-053X/$ - see front matter � 2006 Elsevier Ltd. All rights reserved.

doi:10.1016/j.wasman.2005.12.010

* Corresponding author. Tel.: +90 212 261 90 41; fax: +90 212 259 6762/261 90 41.

E-mail address: kanat@yildiz.edu.tr (G. Kanat).

The organic content of the waste in developing countriesis generally higher. For that reason, composting can be anappropriate waste management alternative. Over 50% of anaverage city’s municipal solid waste stream in a developingcountry could be readily composted (Hoornweg et al.,1999). Composting is a relatively simple process; the com-post operator helps nature take its natural course. Optimi-zation efforts increase the rate of decomposition (therebyreducing costs), minimize nuisance potential, and promotea clean and readily marketable finished product. Compo-sting is highly compatible with other types of recycling.Diverting organic material helps to increase the recoveryrate of recyclable materials, while recycling programs forglass and plastics, which are common MSW compost con-taminants, improve the quality of the finished compost.

In Turkey, the major constituents of MSW are organic,whereas recyclable materials constitute almost one-third oftotal MSW in large cities (Metin et al., 2003). The firstattempts at composting and recycling in municipal plantswere started in 1980s. Some small composting plants (morethan 10 facilities) were constructed as MSW managementalternatives in Turkey. However, they could not be

G. Kanat et al. / Waste Management 26 (2006) 1384–1391 1385

operated efficiently due to administrative, financial andoperational problems; almost all of them were closed aftera few years, while some of them did not operate for morethan a few months. The main reasons for the failures werethe cost of plant operation and maintenance, as well as thelow quality and high cost of the compost product.

As the largest and richest city of Turkey, daily MSWproduction in Istanbul is about 10,000 tons. The popula-tion growth rate of the city is still higher than Turkey’soverall growth rate of 25 per thousand, leading to someplanning problems in the city. Mainly landfilling, formerlyopen dumping (until 1996), has been practiced for disposalof the MSW generated in Istanbul. However, difficulties infinding new landfill sites forced local authorities to searchfor other alternatives with the expectation of reducing theamount of solid waste.

Istanbul city has two continental sides, European andAsian. Recently, there have been two landfilling sites inthe city. About 7000 tons of waste are deposited daily inthe Odayeri Sanitary Landfill located in the European side,where a composting and recycling plant was built in March2001 for treatment of MSW. The design of the compostingand recycling plant was based on the recommendationsfrom different research projects (Basturk, 1980; WHO,1981; CH2M Hill-Antel, 1993; TBU, 2000). However, themain difference was the construction of a more computer-

MUNICIPAL WASTE

WASTE RECEIVING

1000 tons/day %20

LOADING UNIT

1st SIEVE

2nd SIEVE (for coal ash)

MAGNETICSEPARATOR

1st DECOMPOSITION

2nd DECOMPOSITION

FINAL CONDITIONING

PRODUCT(15-40 mm)

>10 mm.

STORAGE

150 tons/day %20

1 260 tons/week

>>15 mm.STORAGE

189 tons/day %20

METALS

Fig. 1. Flow chart of Istanbul municipal soli

ized and automatically controlled plant. The daily capacityof the plant is about 1000 tons. During the test operation ofthe plant, it has been reported that the weight of oversizematerials (OM) above a 80 mm sieve was generally higherthan 40% of the total incoming waste, which mainly con-sists of plastic bags that are full of garbage (Kanat et al.,2002, 2004). This situation resulted in operational prob-lems in the plant and caused a decrease in the amount ofcompost and recovered materials. In the beginning, plantoperators were unable to find a solution to improve the sit-uation. For this reason, in the sorting unit, materials in thefull garbage bags were transferred to the landfill withoutany processing, leading to economic losses.

In this study, the amount and composition of the OM inthe composting and recycling plant were determined, andtheir effects on the plant operation were discussed. Themain objective of the study was to evaluate the economiclosses in the plant. In addition, the reasons for thedecreased amount of compost and recycling materialswas also investigated in the study.

2. Istanbul composting and recycling plant

The flow chart of the composting and recycling plant isshown in Fig. 1. The plant consists of two independentlines with the same properties. Waste is transferred by

HAND SORTING OFRECYCLABLEMATERIALS

MARKETING OF THERECYCLABLEMATERIALS

100 tons/day %20

400 tons/day %20

TO LANDFILL

>80 mm.

%20

40 mm.TO LANDFILL

d waste composting and recycling plant.

1386 G. Kanat et al. / Waste Management 26 (2006) 1384–1391

conveyor belts to two rotary drum sieves, which have adiameter of 3.35 m, length of 12.47 m, 80 mm pore diame-ter and 2� slope. Ferrous metals within the undersize mate-rials that pass through the 80 mm rotary drum sieve aretransferred to the composting area, then removed by amagnetic separator and finally transferred to a scrap metalstationary compactor. Oversize materials from the 80 mmrotary drum sieve are transferred by conveyor belt to ahand-sorting unit in order to separate recyclable materials.MSW from the districts that have high income and use gasor liquid fuel were intended to be transferred to the plant.The non-source separated waste processing facility, whichutilizes mechanized sorting equipment and workers to pickrecyclable material out of the refuse, was designed accord-ing to the recommendations in the feasibility reports. Gen-eral health and safety precautions are taken for workers,such as gloves, vaccinations, etc. No health problems havebeen reported in the plant that were directly related towaste picking (ISTAC, 2002).

The composting and recycling plant was constructed toproduce compost material for the municipality’s parks andgreen areas, but not for sale. There is almost no market forcompost material from solid waste; one of the reasons isthe lack of compost plant in Turkey until recent decades.

3. Recyclable materials in Istanbul

A few municipal waste characterization studies havebeen conducted in Istanbul city. The first intensive solidwaste characterization study was undertaken in 1980 (Bas-turk, 1980). In this study, solid waste samples were ana-lyzed every month of the year in five different districts ofthe city. The second solid waste characterization analysiscontinued for two years and was completed in 1981(WHO, 1981). Another study was conducted between1991 and 1993 (CH2M Hill-Antel, 1993). Results of thisstudy, which included seasonal analyses, are summarizedin Table 1. Sampling districts of all three of the studies weresame.

A characterization study was conducted during planningfor the composting and recycling plant (TBU, 2000). In this

Table 1Waste content in different districts of Istanbul city in 1993 (% weight)

Districts

Material Low income (G.O.Pasa)

Moderate income(Fatih)

Group Winter Summer Winter Summer

Organic matter 43 76 51 50Paper and cardboard 9 4 11 12Plastics (PET, PVC, PE) 7 7 11 9Glass 5 2 3 3Metals 3 1 2 4Textiles 7 5 4 12Other 4 1 2 3Ash, <10 mm 21 4 16 7

study, different waste samples were collected from thetrucks, which enter recently constructed waste transfer sta-tions of the city. Results of the oversize material analyses(above 80 mm sieve) in the study are presented in Table2. It can be seen from the table that the textile content ofOM is higher, especially in some districts, compared tothe average values from past studies, because of the growthof the textile sector in recent decades. On the other hand,food packaging practices have changed. Nowadays, thedisposal of plastics and tetra-pak materials has increased.Similarly, the last waste characterization study used wastesamples from three transfer stations (Demir et al., 2001).Results of this study are provided in Table 3.

4. Methods

During this study, the amount and composition of OMsieve in the plant were determined. Major constituents,such as organic matter, metals, glass, paper and plastics(including some subgroups) were also analyzed by weigh-ing each group and then finding weight ratios. Waste com-position analyses were conducted in the plant.

Waste management authorities commonly characterizeMSW by its physical content. The required size of eachsample extracted for characterization in the surveys showthat there are wide variations in practice. Tchobanoglouset al. (1993) and Martin et al. (1995) suggested that eachsample should be about 91 kg, while ERRA (1993) recom-mended a larger sample size of 100–200 kg. In Hong Kongand Germany, samples are extracted by volume andweight. In Hong Kong, 1 m3 (average 190 kg) of solidwaste was measured (Chung and Poon, 2001), whereas1.1 m3 was used as the extraction standard for each sampleof waste in Germany (Federal Ministry for Environment,1993).

Since, most of the incoming waste contains plastic bagsfull of garbage, two different types of analyses were consid-ered in this study. Details of the sampling procedure of thispart of the study are shown in Fig. 2. In the first part of thisstudy, subgroup analyses of the OM were carried out bycutting all plastic bags and dumping their contents for

High income, solidfuel (Sisli)

High income, liquidfuel (Atakoy)

Moderate income,trading center(Eminonu)

Winter Summer Winter Summer Winter Summer

43 48 60 58 37 5520 17 17 16 23 239 13 12 14 11 76 7 3 5 4 32 2 2 3 2 34 3 2 3 12 21 5 2 1 2 3

16 5 3 1 9 3

Table 2Results of oversize material (above 80 mm sieve) analysis (% weight)

Oversize material Districts’ properties

Residentiala Residentialb Commercial/tourism

Commercial/tourism

Residentialc Residentialb Residential/commercialc

Small-scaleindustry

Marketarea

Marketarea

Recyclable paper 8.2 8.6 9.7 17.8 12.9 11 4.2 4.5 7.6 10.7Recyclable cardboard 6.6 9.9 7.3 10.4 4.1 11 3.2 3.9 5.4 5.1Mixed paper 5.7 4.4 4.7 2.9 5.4 5.6 6 3 2.2 2.4Plastic containers 4.8 4.5 4.4 8.5 6.8 9 5.2 3.6 4.2 3.9Plastic film 17 15.5 13.7 21.7 20.6 13.4 24.5 9.8 18.5 15.3Kitchen waste 4 3.2 1.9 0.8 2.1 5 2.2 1 6.9 7Garden waste 4 11 10.3 4.3 2.2 12.3 0.5 0.6 10.3 16Ferrous metals 9.2 5 2.7 4.1 3.7 3.1 5.7 6.3 12.8 5.9Non-ferrous metals 0.4 1.1 0.6 2 0.4 0.9 0.3 0.1 0.6 0.3Glass 2.3 3.6 4.9 6.1 1.8 2.4 2.6 1.6 5.5 3.4Textiles 11.1 12.5 24.8 3.4 16.1 13.4 21 46.5 6.8 13.3Disposable waste 14.5 9.7 0.7 0.4 14.8 2 13.1 0.7 12.7 6.6Hazardous wasted 1.4 0.8 0.2 0.5 0 0.3 0.9 12 0 0Other 12.2 10.1 14.2 17.2 9 11.7 10.6 8 6.5 10.2

a Moderate income.b High income.c Low income.d Dye containers, batteries, etc.

Table 3Results of waste characterization study of three transfer stations

Material group Rates (% weight) in transfer station

Baruthane Halkali Yenibosna

Paper and cardboard 10.2 10.6 2.5Glass 4.1 5.4 9.1Metals 6.7 2.7 8.0Plastics 4.1 1.7 8.5Textiles 6.1 5.4 4.6Nylon 6.7 12.4 6.9Organic matter 43.0 40.6 45.3Diapers 7.0 12.4 9.1Ash and other 12.1 8.8 6.0Total 100 100 100

GARBAGE BAGS

UnemptiedEmptied

Full bags wereemptied and eachmaterial wasseparated in groups.

Full bags wereweighed with insidematerials, not emptied.

Fig. 2. Details of the sampling procedure.

G. Kanat et al. / Waste Management 26 (2006) 1384–1391 1387

identification of the composition of the waste. Analyseswere conducted for 3 consecutive days, and manually sep-arated wastes were weighed. Sampled waste amounts were323, 382 and 407 kg, respectively, for each day. The mate-rial composition was designated by classifying, weighing,and finding the percentage of each fraction that constitutesthe OM. In the second part of the study, the same method-ology was used, again for 3 days, for classification of mate-

rial with total weights of 368, 310 and 378 kg. Theseanalyses were undertaken without cutting the full plasticbags, which contain recyclable and composting materials.During the analyses, the unemptied bags and the materialsseparated out of the bags were weighed separately.

4.1. Sampling and sorting process

There are some common methods for sampling waste(Bailie et al., 1999). In this study, samples of 1 m3 wereextracted from each selected truck-load in the plant. Grabsamples using a front-end loader were preferred, and theconing and quartering method was not used. This methodis relatively quick and can often be done by facility person-nel without unduly disrupting normal facility operations. Afront-end loader was used to randomly extract samplesfrom the unloaded pile of waste until the desired quantitywas obtained. It was measured volumetrically in a 1 m3

wooden container and then weighed. The waste materialswere then spread out on a plastic sheet where handsortingwas performed by a team of about eight people who wereinstructed on the sorting requirements. Each sorting teamwas supervised by three researchers from Yildiz TechnicalUniversity of Istanbul. The sorting took place in an out-door uncovered, unenclosed area. All sorting studies werecarried out during dry periods.

5. Results and discussion

5.1. Quantity of incoming and oversize waste

In the compost plant, incoming waste and oversizematerial (OM) were weighed with an electronic scale bythe plant operator, ISTAC (Istanbul Metropolitan Munic-ipality Environment Protection and Waste Material

Table 4Total weights of incoming waste and oversize materials

Months Total weightsof incomingwaste (tons)

Total weights of80 mm oversizematerials (tons)

Rates of weights,oversize/incomingwaste (%)

May 23,400 9900 42.3June 16,650 6800 40.8July 15,200 5700 37.5August 15,200 6300 41.4September 20,400 8500 41.7October 19,400 8767 45.2November 14,318 5960 41.6

Average 17,795 7418 41.5

1388 G. Kanat et al. / Waste Management 26 (2006) 1384–1391

Recycling Industry and Trade J.S. Co.). Monthly totalweights of incoming waste and OM are shown in Table 4for the period between May and November 2002. Averagemonthly incoming waste and OM were 17,795 and7418 tons, respectively. The monthly percentages of theOM in the incoming waste are also presented in Table 4.

5.2. Composition of the oversize waste

Waste collection optimization and analyses of majorconstituents of the oversize material in the plant were dis-cussed in an earlier study (Kanat et al., 2002). The resultsof the material analyses, including this study, are given inTable 5. This table also lists the maximum, minimum andstandard deviation of all data. Monthly average valuesshow the results of three analyses carried out during eachseason.

In the second part of the study, analyses of the uncut fullplastic bags were carried out. Generally, those plastic bags,used in garbage collection, were small in size (about 10 l involume) and were obtained from shopping markets.

Table 5Analysis of major constituents of the oversize material in the plant

Groups Monthly average (% weight)

January April August October

Bags full with garbage 43.00 45.13 48.67 46.33Thin bagsa (empty) 7.20 7.13 9.50 8.23Aluminum 0.45 0.57 0.65 0.47Glass 0.73 0.98 0.95 0.60Diapers 4.27 3.85 3.27 3.27Metalsb 6.73 5.12 3.18 5.27Paper and cardboard 4.85 6.43 3.23 3.90Marked bagsc (empty) 4.63 3.30 2.65 4.37Nylon 1.10 1.10 0.30 0.73Organic matter 12.03 14.80 14.63 12.93PET bottlesd 2.20 1.45 1.77 1.07Plastics 2.37 2.26 2.25 1.13Wood 0.38 0.07 0.00 0.57Textiles 6.82 5.33 7.13 8.37Tetra-pak 0.53 0.64 0.68 0.60Other 2.70 1.83 1.13 2.17

a Some of the bags are recycled plastic.b Mainly ferrous material.c Mainly thicker and not recycled plastic.d Mainly used for soft drinks and bottled water.

It was observed that in the plant, the percentage of OMin incoming waste was more than 40% by weight. This wasbecause most of the household waste in plastic bags wasprocessed in the 80 mm sieves without sufficient tearing.On the other hand, the solid waste recycling unit cannotbe managed properly. For that reason, almost all of thebagged materials were transferred to the landfill withoutany further processing. The amount of recycled materialswas found to be very low.

Full plastic garbage bags constitute a high percentage(46.3%) of the landfilled waste (Table 5). The averageorganic matter content without opening the bags was12.9%, and increased to 31.3% when the waste compositionwas determined by tearing all of the plastic bags. There-fore, 18.1% of the OM consists of organic matter that is leftin the plastic bags.

The last part of the study involved an economic eval-uation of the plant. Results from this part of the studyare given in Table 6. It was observed that 31.3% byweight of the waste transferred to the landfill wasorganic material that could be processed in the compostplant, and 26.8% was recyclable material (metals and alltypes of plastics). This implies that approximately 58% ofthe OM transferred to the landfill can be used at thecomposting and recycling plant, assuming appropriateoperational conditions.

Recyclable materials in the Istanbul composting andrecycling plant are mainly plastics and metals. Wet anddirty paper and lesser amounts of other recyclables (glassand tetrapak) are not collected in the plant. The percentageof recyclable material, not inside the bags, was 21%, andincreased to 26.8% when the waste composition was deter-mined by tearing all of the plastic bags. Hence, 5.7% of theOM consists of recyclable materials that are disposed in the

Maximum Minimum Average Standard deviation

50.60 40.00 46.28 2.8611.20 5.10 7.92 1.810.80 0.40 0.53 0.120.30 1.20 0.82 0.225.30 1.20 3.66 0.95

11.20 0.70 5.18 2.427.10 2.60 4.60 1.445.60 1.80 3.94 1.002.20 0.00 0.91 0.73

16.10 11.50 13.60 1.422.70 0.80 1.62 0.503.10 0.00 2.20 0.741.40 0.00 0.25 0.36

11.00 4.00 6.91 2.020.80 0.40 0.61 0.113.50 0.80 1.96 0.70

Table 6Composition analysis of the oversize materials (emptied bags)

Material group Weight (%)

Day 1(9 October)

Day 2(10 October)

Day 3(11 October)

Average(%)

Thin bagsa

(empty)11.8 16.2 14.0 14.0

Organic matter 33.4 28.8 31.6 31.3Paper and

cardboard6.2 7.9 4.9 6.3

Metalsb 2.2 2.4 2.0 2.2Aluminum 1.9 1.0 0.4 1.1Glass 2.2 0.0 1.2 1.1Marked bagsc

(empty)3.7 2.6 4.3 3.5

Nylon 1.5 0.8 1.4 1.2PET bottlesd 2.8 3.7 1.0 2.5Plastics 3.1 3.1 0.8 2.3Wood 3.7 0.5 0.4 1.5Textiles 17.0 25.1 26.6 22.9Tetra-pak 1.2 1.6 0.8 1.2Diapers 7.7 4.7 10.3 7.6Other 1.6 1.6 0.3 1.3Total 100 100 100 100

a Some of the bags are recycled plastic.b Mainly ferrous material.c Mainly thicker and not recycled plastic.d Mainly used for soft drinks and bottled water.

G. Kanat et al. / Waste Management 26 (2006) 1384–1391 1389

landfill. Materials within these bags cannot be processed inthe composting area or in the recycling facility.

5.3. Economic loss due to inappropriate operational

conditions

The existing operational conditions at the compostingand recycling plant result in some economic losses. Ineffi-cient operational conditions in the recycling area and thelarge amount of OM resulted in an increase in the quantityof unprocessed solid waste. Therefore, the cost of transpor-tation and the new landfill area requirements must also beconsidered.

Construction and operating costs of new areas in thelandfilling site, and the transportation cost of leachate are5, 1.3 and 0.8US$/ton of waste, respectively (assuming anexchange rate of 1.6 million Turkish Liras per US$). Thetotal cost is US$7.1/ton waste. Furthermore, the transpor-tation cost of the solid waste from the composting plant tothe landfill area is US$1.8, and hence the total landfillingcost would be US$8.9/ton of waste.

In this manner, waste materials can be used to calculatethe economic loss of the plant. The percentage of total OMin incoming waste was 41.5% (Table 4). It was also calcu-lated that 58% of the transferred oversize materials to thelandfill could be used at the plant. Hence, if better opera-tional conditions could be implemented, 24% of the land-filled waste could have been used in the plant ascomposting and recycling material. The resulting economicloss was significant, calculated at US$2136 for the plant,which has lost 240 tons of waste per day. The total lost

amount of the loss is estimated at US$640,800 for approx-imately 300 work days in a year.

The quantity of solid waste that is transported to thelandfill area without being processed in the plant is approx-imately 72,000 tons/yr, and the volume of these wastes is250,000–300,000 m3/yr. Furthermore, the cost of leachatetreatment and other costs are expected to increase consider-ably. The main operational cost items of the plant are elec-tricity and diesel fuel, mainly used for activities liketransporting the waste to the plant, processing, and recy-cling. The electricity used at the plant is 9 kWh/ton of solidwaste processed, and the average monthly diesel oil con-sumption is 7.2 tons. Comparing existing operational condi-tions in the plant with the optimized conditions in which theOM is utilized, the electricity and diesel oil consumption areapproximately 24% higher if inappropriately processed solidwaste quantities are transported to the landfill area.

5.4. Importance of oversize material in the operation

It can be seen from the results of this study that theamount of solid waste transferred to the landfill area canbe reduced considerably and it can be used as both compo-sting and recyclable material, if operating conditions areimproved. To achieve this, plastic bags should be torn openand emptied, and their contents should be sent to therotary drum sieve in order to utilize the organic and therecyclable materials that come to the plant in full plasticbags. The blades of the drums were not suitable for thisoperation. In order to improve operating conditions, eventhe larger organic materials such as watermelon rind andcabbage must be broken into pieces with appropriateequipment. Reducing the usage of plastic bags for garbagecollection in the city is not easy. Plastic bags are very com-mon and easy to use by people. For this reason, the prob-lem of separation needs to be addressed inside the plant.

At the end of study, the number of blades in the rotarydrum were increased by the plant operator, and a workerwas placed in the loading unit to tear open the bags by hand.Unfortunately, the study could not be continued for a longtime after that because of financial restrictions and labordemand. The situation was improved in the plant, but someprecautions are still needed for better operating conditions,such as optimizing the division of waste collection districts,implementing a separate collection system, etc.

5.5. Source separation and its significance

It can be seen from the operational problems and inter-ruptions of the plant that source separation would also bean important factor for improving processing conditions.Municipal waste, without source separation, is processedin the composting and recycling plant as planned in the fea-sibility reports. For that reason, optimization of operationsand appropriate waste collection (higher organic and recy-clable content) from potential districts of the city are stillimportant factors for the plant. As reported in a study of

1390 G. Kanat et al. / Waste Management 26 (2006) 1384–1391

the World Bank (Hoornweg et al., 1999), source separationis one of the most important factors for successful andcost-effective composting. This can be clearly seen inanother compost plant (capacity of 50,000 tons/yr) inAntalya city (Turkey) that processing primarily waste fromtourist locations and hotels. In Antalya city and the nearbyregion, organic material is collected separately andcomposted anaerobically in a simpler composting plant.Almost no problems have been encountered in this plantwith regard to waste composition (GATAB, 2004).

In Istanbul city, separate collection is not yet used exten-sively, except in certain areas in wealthier districts of thecity, where some studies have shown that people are muchmore willing to separate materials for collection (Metinet al., 2003). These wealthier districts’ municipalities applyrecycling systems on a limited scale but still have adminis-trative and operational problems. Separate collection in thecity was planned to progress in parallel with the other solidwaste management alternatives, but unfortunately it is stillin planning phase. On the other hand, individual collectionactivities (scavenging, etc.) take place at all levels of thewaste collection process but no study has been made withregard to the amount collected.

In Turkey and Istanbul city, a strong market demandexists for almost all types of recyclable materials. Glassand paper recycling has been conducted primarily at anindustrial scale for a long time. Recyclable materials aretypically collected by individual collectors from the streets,but not by municipalities. Recycling rates can be improvedby separate collection of municipal solid waste.

6. Conclusion

In this study, it has been found that the annual economicloss of the plant, due to inappropriate operations, was about640,800US$. Compost quality in the plant had been satis-factory until recently. To increase the amount of compostand captured recyclable materials in the plant in Istanbul,all plastic garbage bags should be torn as the first step ofthe process. However, appropriate waste collection (higherorganic and recyclable content) from potential districts ofthe city are still important factors for the plant. The bestway to improve the situation will be source separated collec-tion; at least the separation of the wet from dry fractions.

Varying waste composition (e.g., higher textile portions)and low quantities of compost and captured recyclablematerials could be problems for the plant’s future. For thatreason, the municipality and plant operator (a trade incor-poration of the municipality without competitors) need tobe willing to implement measures to optimize operationsat the plant. In Turkey and some other developing coun-tries, it is difficult to operate plants optimally, especiallypublicly owned plants, due to investment and administra-tive problems. The most important inadequacy in any envi-ronmental management activity in those countries are theoperating problems and lack of research during operationof the plants.

Although the organic material content of the waste ishigh in Turkey, only three composting plants are beingactively operated in the country. All three are in large cit-ies. Some other small-scale plants are being planned inother cities. However, mainly due to financial and adminis-trative problems in the country, it may take a long time tofinish construction of those facilities. For that reason, land-filling will be the main alternative for solid waste disposalin the near future. Composting can be advantageous onlywhen it is a simple, low cost process. Markets for solidwaste compost products can also increase the interest inthis alternative in the country.

Acknowledgments

The authors thank Prof. Dr. Adem Basturk for hisindispensable support given to this study. The authorsthank ISTAC (Istanbul Metropolitan Municipality,Environment Protection and Waste Material RecyclingIndustry and Trade J.S. Co.) for technical and financialsupport.

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