SOLID WASTE

Outline Definition Generation Collection Types Sources Disposal

Solid waste Solid waste : all the wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted

Solid waste management system elements

Solid waste Factors affecting solid waste generation: 1- Geographic location 2- Season of the year 3- Collection frequency (affect amounts collected) 4- Public attitude 5- Legislations 6- Use of kitchen waste grinders 7- Characteristics of Populace 8- Lack of recycling and waste minimization

Solid waste Generation Rate Expression unit for generation rates *Residential kg/c/d --------kilogram per capita per day Estimation of unit solid waste generation rates for a Residential Area. From the following date estimate the unit waste generation rate for a residential area consisting of approximately 1,000 homes. The observation location is a local transfer station, and the observation period is 1 week. each household is comprised of 3.5 people.

Solid waste Generation Rate (1) Number of compactor truck loads = 10 (2) Average size of compactor truck = 15.3 m3 (3) Number of flatbed loads = 10 (4) Average flatbed volume = 1.15m3 (5) Number of loads from individual residents private cars & truck = 20 (6) Estimated volume per domestic vehicle = 0.23m3

WASTE GENERATION RATES Solution 1. Set up the computation table

Solid waste Generation Rate 2. Estimate the unit waste generation rate Unit rate = --------------------- = 1.35 kg/capita/day 33116 kg/wk (1000x3.5)(7days/wk)

Collection Route Eight(8) condition- to prepare a good Heuristics routing 1) Do not fragment routes, keep in same area. 2) Collection Time + Haul time must be Equal for each route 3) Start collection as close to municipal garage. 4) Do not collect heavily traveled streets during rush hours. 5)Start routes at higher elevations. 6) Make right turn as much as possible. 7)Avoid dead-end roads. 8) Routes must not be overlapping.

COLLECTION ROUTING- EXAMPLE END START

START ONE WAY END

EX1: For the following neighborhood has a one-way street running east to west. In general, trucks can only pick up from one side of the street at time. a) Assuming pickups can be made from both sides of the street at the same time on the one way street , devise a heuristic route in which no house on the route is passed twice (no deadheading). b) If trash can only be picked up from one side of the one- way street at a time (it’s a busy street), modify your heuristic pickup route with a minimum of deadheading and turns

Solid waste collection Total time of one day refuse or waste collection

EX2: consider the following data for a municipal waste collection system: Travel time garage to route =20 min. Travel time , route to disposal site= 20 min. Time to unload at disposal site= 15 min. Time from disposal site to garage= 15 min. Time spent on worker breaks= 40 min/day Packer truck volume =19m3 Time loading per stop = 1min. quantity of daily collected wastes = 150 m3/day Container capacity 10 m3/container Collection time= 2 hours per trip a) How many hours per day would the crew have to work if it fills the trucks twice per day?

EX3: Suppose it takes 0.4 hour to drive from the garage to the beginning of the route, 0.4 hours to drive between the route and the disposal site, and 0.25 hours to return from the disposal site to garage. It takes 0.2 hours to offload a truck at the disposal site. The crew is given two 15 minutes breaks per day and another 30 minutes is allowed for unexpected delays ( total 1 hour) . If two trips are made to the disposal site each day, how much time is left in 8 hours shift for actual refuse collection.?

1) HAUL CONTAINER SYSTEM (HCS) TYPES OF MSW COLLECTION SYSTEMS 2 TYPES OF COMMON MSW COLLECTION SYSTEM:- 1) HAUL CONTAINER SYSTEM (HCS) Container full of MSW hauled to a single collection and emptied containers returned to its NEXT container location. (truck carry empty container from dispatch station to first container location) Vehicle used( hoist truck, Tilt Frame, Truck tractor trash trailer)- high MSW generation 2) STATIONARY CONTAINER SYSTEM (SCS) Container full of MSW hauled to a single collection and emptied containers returned to SAME MSW on site collection location. (Trucks carrying empty container from dispatch station to first container location) - Vehicle used( front loading, side loading, rear loading, compactor )-

TYPES OF MSW COLLECTION SYSTEMS Hauled container system (HCS)  Ideally suited for the removal of wastes from sources where the generation rate is high and relatively large containers are used.  Large container reduces the handling time, unsightly accumulations and unsanitary conditions.  Main advantages – required only a single member crew  However, pick up activity required a round of trip to disposal site.  The truck have to travel to and from deposit site.

TYPES OF MSW COLLECTION SYSTEMS Stationary container system (SCS)  The waste container remain at the point of waste generation.  2 types of SCS -Those in which mechanically loaded collection vehicle with compaction -Manually loaded collection vehicles  Trips to disposal site or transfer station made after the contents of a number of containers collected and compacted.

MSW COLLECTION SYSTEMS 1) HAUL CONTAINER SYSTEM (HCS) MSW COLLECTION SYSTEMS Hoist Truck Tilt Frame Trash Trailer

MSW COLLECTION SYSTEMS HAUL CONTAINER SYSTEM (HCS)-Conventional Mode MSW COLLECTION SYSTEMS 2 3 n Truck from dispatch station beginning of daily route, t1 Container Location 1 Pick up loaded container Haul loaded Container Haul empty container to original; pick up Location Transfer station, MRF (content of container are emptied) Truck to dispatch station end of daily route, t2 Deposit Empty container Drive to next container location

MSW COLLECTION SYSTEMS 1) HAUL CONTAINER SYSTEM (HCS)-Exchange Container Mode Deposit empty container from previous location and pick up loaded container Container Location 1 2 3 n Truck with empty container from dispatch station beginning of daily route, t1 Haul empty container originally at location 1 to location 2 Truck with empty container to dispatch station end of daily route, t2 Haul loaded Container from location 1 Transfer station, MRF or disposal site

MSW COLLECTION SYSTEMS 1) HAUL CONTAINER SYSTEM (HCS) MSW COLLECTION SYSTEMS For haul container system Phcs= pc +uc +dbc Phcs = Pick up time per trip for hauled container system, h/trip pc = time required to pick up loaded container, h/trip uc = time required to unload empty container, h/trip dbc = time required to drive between container location, h/trip

MSW COLLECTION SYSTEMS 1) HAUL CONTAINER SYSTEM (HCS) MSW COLLECTION SYSTEMS Nd =[H(1-W) – (t1- t2)]/ Thcs Nd = number of trips per day, trips/day H = length of work day, h/d W = off-route factor, expressed as a fraction t1- = time to drive from dispatch station (garage) to first location to be serviced for the day, t2- = time to drive from last container to serviced for the day back to dispatch station (garage) ,h. Tscs = time per trip for haul container system, h/trip

MSW COLLECTION SYSTEMS 1) HAUL CONTAINER SYSTEM (HCS) MSW COLLECTION SYSTEMS Nd = Vd /c f ………an alternative computation technique. Nd = number of trips per day, trips/d Vd = average daily quantity of waste collected, m3/d c= average container size, m3/trip f=weighted average container utilization factor

MSW COLLECTION SYSTEMS 2) STATIONARY CONTAINER SYSTEM (SCS) Empty collection vehicle from dispatch station- beginning of daily route, t1 Load contents from container's) at pick up location into collection vehicle 2 3 n Drive to next container location Transfer station, MRF (content of container are emptied) Drive empty collection vehicle to beginning of next collection route or return to dispatch station-end of route, t2 Solid waste pick up location 1 Collection route Drive loaded collection vehicle to location where contents of vehicle will be emptied

MSW COLLECTION SYSTEMS 2) STATIONARY CONTAINER SYSTEM (SCS) MSW COLLECTION SYSTEMS For Stationary container system Pscs= Ct (uc) +( np- 1 )(dbc) Pscs = pickup time per trip for stationary container system, h/trip Ct = number of container emptied per trip, container/trip np = number of container pick up location per trip, location/trip uc = average unloading time per stationary containers for stationary container system, h/container dbc = average time spent driving between container location, h/location

MSW COLLECTION SYSTEMS 2) STATIONARY CONTAINER SYSTEM (SCS) MSW COLLECTION SYSTEMS Ct = v.r /c f Ct = number of containers emptied per trip, containers/trip v = volume of collection vehicle, yd3/trip r = compaction ratio c = container volume yd3/container f = Weighted container utilization factor

MSW COLLECTION SYSTEMS 2) STATIONARY CONTAINER SYSTEM (SCS) MSW COLLECTION SYSTEMS Nd = Vd /v.r (SCS) Nd = Vd /c f (HCS). Nd = number of collection trips required per day, trips/d Vd = average daily quantity of waste collected, yd3/d v = volume of collection vehicle, yd3/trip r = compaction ratio

MSW COLLECTION SYSTEMS 2) STATIONARY CONTAINER SYSTEM (SCS) MSW COLLECTION SYSTEMS Time required per day, following equation:- H = [(t1- t2) + Nd(Tscs)] ……………. (day) (1-W) H = Time required per day t1- = time to drive from dispatch station (garage) to first location to be serviced for the day, hours t2- = time to drive from last container to serviced for the day back to dispatch station (garage), hours Nd = number of collection trips required per day, trips/d Tscs = time per trip for stationary container system, h/trip W = off-route factor, expressed as a fraction

EX4: Consider the following data for a municipal waste EX4: Consider the following data for a municipal waste collection system: Travel time garage to route =20 min. Time to dispatch station= 15 min. Compaction ratio =4 Time loading per stop = 1min. Weighted container utilization factor= 0.67 Off-route factor= 0.15 Quantity of daily collected wastes = 150 m3/day Container capacity 10 m3/container Times per trip = 3 hrs/trip Daily working hours = 7 hours / day a) How much truck volume to collect the above waste?

EX5: Based on traffic studies at similar parks, it is estimated that the average time to drive from the garage to the first container location and from the last container location to the garage each day will be 15 and 20min, respectively. Two trucks are being considered: Truck volume (m3) 15 27 Off-route factor, W 0.15 0.15 Times per trip , hrs/trip 4 4.5 Solid waste generation 7 8.5 per day, ton Density of solid waste, kg/m3 35 35 How many hours per day would each truck and crew have to operate to fill the trucks each day?

WASTE DISPOSAL No matter what processing is done, there will be some residue that needs to be disposed of safely Options for disposal Modern, engineered landfill Incineration.

WASTE DISPOSAL Sanitary Landfill Is defined as a land disposal site employing an engineered method of disposing of solid wastes in a manner that minimizes environmental hazards by spreading the solid wastes to the smallest practical volume, and applying and compacting cover material at the end of operation of each day. Systems- Sanitary Landfill i. Gas collection system ii. Leachate collection system iii. Monitoring well

Solid Waste - Sanitary Landfill

A landfill in México showing geomembrane in one of the slopes.

Cross-Section of Sanitary Landfill WASTE DISPOSAL Cross-Section of Sanitary Landfill

Sanitary Landfill-Site selection consideration WASTE DISPOSAL Sanitary Landfill-Site selection consideration 1. Public Opinion/opposition 2. Proximity of major roadways 3. Speed Limits 4. Load limits on roadways 5. Bridge capacities 6. Traffic patterns and congestion 7. Haul distance (time) 8. Detours 9. Hydrology

Sanitary Landfill-Site selection consideration WASTE DISPOSAL Sanitary Landfill-Site selection consideration 10. Availability of cover material 11. Climate (e.g. floods, mud slides, snow) 12. Buffer areas around the site (e.g. high trees on site perimeter) 13. to operate for at least 5 years 14. ultimate use of completed landfill

Sanitary Landfill-Methods of Operation WASTE DISPOSAL Sanitary Landfill-Methods of Operation Area Method Solid waste is deposited on the surface, compacted, then covered with a layer of compacted soil at the end of a working day. The cover material may come from on or off site.

WASTE DISPOSAL Area Method

Area method for constructing a sanitary landfill

Sanitary Landfill Cross Section - Area Method WASTE DISPOSAL Sanitary Landfill Cross Section - Area Method

Cell - volume of material place in the landfill Cell - volume of material place in the landfill during one day operating period. Daily cover - 6 to12 in of native soil/ alternative material applied into surface of the landfill at end of each one day - to control the blowing of wastes material. Lift - complete layer of cells over the native area of the landfill

Bench - height of the landfill exceed 15 to 20 m. - to maintain the slope stability of the landfill Final lift - final cover layer Final cover layer - applied to entire landfill surface after all landfilling operations are complete. - usually multiple layers of soil/geomembrane material

Sanitary Landfill-Methods of Operation WASTE DISPOSAL Sanitary Landfill-Methods of Operation Trench Method: A trench is excavated and the solid waste is placed in it and compacted; and the soil that was taken from the trench is then laid on the waste and compacted. This method is used on level or gently sloping land where the water table is low. The advantage of this method is that the soil taken from the trench can readily be used as daily cover and final cover.

WASTE DISPOSAL Trench Method

Trench method for constructing a sanitary landfill

Environmental Considerations of Sanitary Landfill WASTE DISPOSAL Environmental Considerations of Sanitary Landfill 1.A well designed and operated landfill will minimize vectors (carrier of disease), water and air pollution. 2.Burning is not permitted in a landfill. Keeping the waste covered will prevent the production of flies, control of rodents and fires.

WASTE DISPOSAL Landfill Leachate: Liquid that passes through the landfill and that has extracted dissolved and suspended matter from it is called leachate. Liquid enters the landfill from external sources such as rainfall, surface drainage, groundwater, and the liquid in and produced from the decomposition of the waste.

Leachate Collection System WASTE DISPOSAL Leachate Collection System Impermeable liner Granular material Collection piping Leachate storage tank Leachate is trucked to a wastewater treatment facility

WASTE DISPOSAL Estimating Landfill Requirements Sizing of landfill requires estimates of: - The rate at which wastes are discarded. The density of wastes when they are compacted in the fill. The density of wastes will be depends on how well it is spread and compacted . For MSW, the density in a landfill will usually between 480 to 600 kg/m3.

WASTE DISPOSAL vMSW= Vcell = Alift =