Micro Waste collection logistics
Micro Waste collection logistics example
Setting It Up: Basic ServicesWaste CollectionWaste collection and removal are serious health issues. A table summarizes themain collection systems. Criteria and design ofhandcartsfollows in a short summary.Collection SystemsSource:Involving micro- and small enterprises in Municipal solid waste management: Guidelines for municipal managers. Hann, Hans Christiaan, Coad, Adrian, and Lardinois, Inge. 1998. International Training Center of the ILP, SKAT, WASTE. Turin, Italy. pp 90.KEY POINTS CONCERNING MAIN COLLECTION SYSTEMSSystemDescriptionAdvantagesDisadvantagesSHARED: Residents can bring out waste at any timeDumping at designated locationResidents and other generators are required to dump their waste at a specified location or in a masonry enclosure.Low capital costsLoading the waste into trucks is slow and unhygienic. Waste is scattered around the collection point. Adjacent residents and shopkeepers protest about the smell and appearance.Shared containerResidents and other generators put their waste inside a container which is emptied or removed.Low operating costsIf containers are not maintained they quickly corrode or are damaged. Adjacent residents complain about the smell and appearance.INDIVIDUAL: The generators need a suitable container and must store the waste on their property until it is collected.Block collectionCollector sounds horn or rings bell and waits at specified locations for residents to bring waste to the collection vehicle.Economical. Less waste on streets. No permanent container or storage to cause complaints.If all family members are out when collector comes, waste must be left outside for collection. It may be scattered by wind, animals and waste pickers.Kerbside collectionWaste is left outside property in a container and picked up by passing vehicle, or swept up and collected by sweeper.Convenient. No permanent public storage.Waste that is left out may be scattered by wind, animals, children or waste pickers.If collection service is delayed, waste may not be collected or some time, causing considerable nuisance.Door to door collectionWaste collector knocks on each door or rings doorbell and waits for waste to be brought out by resident.Convenient for resident. Little waste on street.Residents must be available to hand waste over. Not suitable for apartment buildings because of the amount of walking required.Yard collectionCollection labourer enters property to remove waste.Very convenient for residents. No waste in street.The most expensive system, because of the walking involved. Cultural beliefs, security considerations or architectural styles may prevent labourers from entering properties.Frequency of collection:Some communities are accustomed to a collection seven days a week, whilst other collection agencies are striving for just once each week. If fly breeding is to be controlled, the waste should be collected twice a week in hot climates. Other factors to consider are the odours caused by decomposition and the accumulated quantities. If residents are accustomed to daily collection it may not be politically feasible to reduce the frequency to twice a week.In some cities waste is collected on the day of rest (Sunday or Friday). Some collect waste at night, perhaps for cultural reasons or because of the weather or traffic congestion.Handcarts and Small Collection VehiclesSource:Involving micro- and small enterprises in Municipal solid waste management: Guidelines for municipal managers. Hann, Hans Christiaan, Coad, Adrian, and Lardinois, Inge. 1998. International Training Center of the ILP, SKAT, WASTE. Turin, Italy. pp 94-95Three common types ofprimary collection vehiclesare: the handcart which is pushed by the operator as he walks along.- very limited capacity in terms of volume and capacity- carries 0.25 to 1 cu.m. with a maximum range of 1 km- very cheap- operated by one person the pedal tricycle with a tray or box in front of or behind the operator.- loads up to 1.5 cu.m.- range greater because of higher speed when empty- lifetime about 2 years- no negative impact on environment animal-drawn cats, often pulled by donkeys.- common around the world; until recently Cairo Municipality used donkey carts- carry up to 1.5 cu.m. and range of up to 7 km.- cost of feeding and caring for animals added factor- negative impact on environment is excretaSimple, motor powered vehicles should be considered where longer distances require larger payloads and higher speeds, or where slopes are based on small motorbikes.A wide variety oftrucksare used for collection. Factors to consider in selecting include: the weight of waste that the truck can actually carry cost of purchase and operation, including fuel and maintenance delays in obtaining spare parts suitability of the vehicle for the local roads considering width, congestion, and surface conditions ease of loading and unloadingNote: Use same make and models as in other sectors.Criteria for design of handcartsHow much to carry?If material is required to be moved over 500 meters, it will be preferable to minimize the unproductive travelling time and maximize load. A labourer can push 150 kg of waste in a well-designed and maintained cart.If the cart is used for street sweepings, it is appropriate for the capacity to be less because:- the waste takes more time to collect so it may not be possible to collect the full 150 kg during the day.- there may be community storage containers at frequent intervals so that it is not necessary to carry the waste over a long distance.How is the waste transferred:Too often one sees labourers tipping the contents of their carts onto the ground and then scooping the waste up into another container for transfer. This practice is inefficient (wasting time), unhealthy (forcing the labourer to touch or have close contact with waste), polluting (often some of the waste is left on the ground or is scattered by the wind).There are two simple ways of avoiding this problem:- use a split-level site so that waste can be tipped directly from the cart into the bulk container.- containerize the refuse in a number of bins that are small enough so that they can be lifted and tipped into the bulk container.General design features:- The size of the bins should be large enough that big items of waste cannot bridge across the rim and prevent the efficient utilization of the bins capacity.- Bins that are rectangular may be difficult to pack if the dimensions of large items are larger than the smaller horizontal dimension of the bin.- Square and rectangular bins may be easily deformed and develop dangerous jagged projections at the corners.- Bins that are circular do not fit together well, considerable space is lost between bins.- Wheels:- Number: If the cart has only two wheels, the operator is always required to apply a lifting force, adding to fatigue and possible back injuries. At least three wheels are suggested. But carts with three wheels may roll by themselves if left on sloping ground. Four wheels make the cart more stable allowing easier crossing of a hole in the road.- Size: Large wheels are better on rough surfaces, and, with poor bearings, cause less rolling resistance. However, larger wheels are heavier and more expensive, and may obstruct the removal of containers.- Contact surface: A wide rim is necessary on soft ground. A contact surface - pneumatic tire or solid rubber tire - reduces the difficulty of pushing on stony or rough ground, but - Bearings: Simple journal bearings are rarely lubricated as they should be. Ball or roller bearings are more expensive and must be protected from dust.- Durability: Bicycle wheels are generally not strong enough for this kind of duty. Motor cycle wheels have proved well suited, but they are likely to be more expensive.Note: It is important to design and specify all items of equipment carefully - even simple equipment such as brooms, other tools, and carts. These items are used in large numbers and so the impact or a more efficient design or durable design can be very significant in economic terms.