MUNICIPAL SOLID WASTE MANAGEMENT SYSTEM

SOLID WASTE PROCESS SYSTEM WRITE UP

 

100s of acres of land is locked in dumping yard over the period of many decades. The waste from the city is dumped in the yard for many years. Over the period, the organic part of the waste gets partially bio degraded and is converted into city compost. If the material is segregated at the rate more than the rate at which new waste arrives at the dumping yard, then the same land will be available for in coming waste. Simultaneously decentralized waste management system should be put at the locations where large quantity of organic waste is generated such as big vegetable market, APMC yard, fruit market and large eating house.

The matured city compost mix can easily be separated into inerts like stones, metal, glass, which is value added material and easily picked up by reprocessors. The plastics can be de dusted, compacted and densified which is again easily picked up by reprocessors or by cement industry. The manure / city compost of powdered and can be converted in to large consumption, value added products as it is not recommended by various scientific reports as fertilizer.

 

 

PRINCIPLE

            The segregation of decade old composted material / hills at dumping yards by sieving , plastic compaction, conversion in to products of large consumption.

PROCESS

            The hills of composted waste (collected over period of years or decades which is now de composed) are screened using ore dressing equipments like trommels, vibrating screens into three fractions. The larger fraction i.e. top of the screen will mainly be of plastic materials which will further be de dusted and compacted into bales. The bales are low volume and high density hence economically transported for recycle or to cement industry.

            Second fraction is of stones, rocks, metal, glass bottles which is inert in nature and is in demand.

The smallest size (below 25 mm) is clay with organic content material and depending upon its analysis with respective to moisture free organic matter, clay content can be converted into value added products of large consumption.

 

EXPERIMENTAL WORK AND FINDINGS :

Volumetric Composition of Yard Waste

Basis : 600 cuft (20m3) of Dumping Yard Waste

Size Separation by Screening :

  1. Volume of Material above 100 mm screen size = 2 to 3 m3

Type & quality of material above 100 mm screen size

  • Plastics (1 to 2 m3), Cloth pices, rubber articles, gunny bogs, jute articles (1 to 2 m3)
  • Stones (Small quality)
  1. Volume of material below 100 mm and above 25 mm ( -100, +25mm)=2 to 3 m3

Type and quality of material (-100, +25mm)

  • Plastics pouches (0.5 to 1m3), rubbles, gravels (1 to 2 m3)

 

  1. Volume of material below 25 mm and above 10 mm = 2 to 3 m3

Type and quality of material (-25, +10mm)

Coarse gravel, stone pieces, coarse sand

  1. Volume of material below 10 mm = 12 to 14 m3

Type and quality of material (-10mm)

  • Clay, sand, compost
  • % Volumetric Composition

Sr.No.

Type

% composition

 

Top Product

 

1

Loose Plastics

Upto 15%

2

Combustibles like cloth, jute, rubber

Upto 15%

3

Stone pieces (above 100 m)

Upto 0.5%

 

Middle Product

 

4

Pouches /Small combustibles

Below 5%

5

Rubbles, gravels above 25mm

Below 5%

6

Coarse sand, gravel, stone pieces above 10 mm

Upto 10%

 

Fine Produce

 

7

Clay, fine sand, compost below 10 mm

Upto 70%

  • Management of Various fractions / products of size separation
  • Top Product :
  • Fraction 1 : Loose Plastics 15% (V/V)
  • Dedusting, compaction (volume reduction by 80 to 90%) resulting in Bales of 30 to 40 kg. can be economically transported for recycling or cement industry.
  • Fraction 2 : Combustibles like cloth pieces, Jute, rubber items – up to 15% (V/V)
  • Incinerator – With or without Heat Recovery
  • Fraction 3 : Inert stone pieces : Safe to collect and can be used for construction
  • Middle Product :
  • Fraction 1 : Pouches / Small combustibles : up to 5% (V/V)
  • Incinerator : with or without Heat Recovery
  • Fraction 2: Inert Rubbles, large size gravels . . . up to 5%
  • Safe to collect and can be used for construction
  • Bottom fraction 3 : Inert coarse sand, small size gravels, stone pieces up to 10%
  • Safe to collect and can be used for construction.
  • Fine Product :
  • Fraction 1 : Clay, fine sand, compost, up to 60%
  • Safe to collect and can be used for Brick making

 

  • Dumping yard city compost
  • Average Composition                      Survey                       Our experimental value
  • (By weight)               (By Volume)
  • Paper, Cloth, Rubber :           upto 3%                    upto 15%
  • Moisture :           upto 20%                  upto 10%
  • Plastics :           3 to 4 %                     upto 15%
  • Inerts :           43 to 50%                 upto 60%
  • Organic Matter :           upto 30%                  upto 15%

 

Our Principle of the process

 

  • Decentralized Waste Management hence no transportation and less segregation efforts.
  • Waste management by “ONE Who generates & at the place and at the time of its generation”

Hence primary responsibility of Waste Management Lies with the “Generator” of Waste and not on “Others”

  • Waste is converted into valve added product like Compost.

 

It is a decentralized waste treatment and value addition technology. It is based on the principle of scientific treatment of waste at the place of its generation and by the shortest time laps (at the place and at the time of generation of waste)

Hence, the broadly segregated waste is available. The only pre treatment required is separation of plastics, glass, stones from organic waste.

 

INTRODUCTION

Use of plastics in the form of packaging materials, wrappers, carry-bags and other commodity items has become integral part of daily life. While plastics items waste having relatively low volume and reasonable weight and bottles are readily picked-up by rag pickers and kabariwala system, the low weight – high volume items become the part of municipal solid waste and get transported up to dumping yard. The thin, low density (High Volume-Low Weight) plastics become not only eye soar but also cause great nuisance to public at large. It flies all over and creates pollution. The quantum of solid waste is ever increasing due to increase in population, developmental activities, changes in life style, and socio-economic conditions, Plastics waste is a significant portion of the total municipal solid waste (MSW). It is estimated that approximately 10 thousand tons per day (TPD) of plastics waste is generated i.e. 9% of 1.20 lacs TPD of MSW in the country. The plastics waste constitutes two major category of plastics; (i) Thermoplastics and (ii) Thermoset plastics. Thermoplastics, constitutes 80% and thermoset constitutes approximately 20% of total post-consumer plastics waste generated in India. The Thermoplastics are recyclable plastics which include; Polyethylene Terephthalate (PET), Low Density Poly Ethylene (LDPE), Poly Vinyal Choloride (PVC), High Density Poly Ethylene (HDPE), Polypropylene(PP), Polystyrene (PS) etc. However, thermoset plastics contains alkyd, epoxy, ester, melamine formaldehyde, phenolic formaldehyde, silicon, urea formaldehyde, polyurethane, metalised and multilayer plastics etc. The environmental hazards due to mismanagement of plastics waste include the following aspects: ❯ Littered plastics spoils beauty of the city and choke drains and make important public places filthy; ❯ Garbage containing plastics, when burnt may cause air pollution by emitting polluting gases; ❯ Garbage mixed with plastics interferes in waste processing facilities and may also cause problems in landfill operations;

COMPOSITION OF MUNICIPAL SOLID WASTE

 

 PLASTIC WASTE RAISES THE FOLLOWING ENVIRONMENTAL ISSUES:

  • Indiscriminate dumping of plastic waste on land makes the land infertile due to its barrier properties.
  • Burning of plastics generates toxic emissions such as Carbon Monoxide, Chlorine, Hydrochloric Acid, Dioxin, Furans, Amines, Nitrides, Styrene, Benzene, 1, 3- butadiene, CCl4, and Acetaldehyde.
  • Lead and Cadmium pigments, commonly used in LDPE, HDPE and PP as additives are toxic and are known to leach out.
  • Non-recyclable plastic wastes such as multilayer, metalised pouches and other thermoset plastic poses disposal problems.
  • Sub-standard plastic carry bags, packaging films pose problem in collection and recycling. Littered plastics give unaesthetic look in the city, choke the drain and may cause flood during monsoon .
  • Garbage mixed with plastics interferes in waste processing facilities and also cause problems in landfill operations.

 

3 R PRINCIPLE OF WASTE MANAGEMENT :

 Reduce   Recycle  Reuse

 3-R Principle is well accepted and recommended principle of waste management.

The present technology is also based on 3-R principle. The volume of the waste is reduced by 85 to 90% which makes the waste recyclable for reuse.

 PROCESSING METHODOLOGY :

          Following steps are involved.

  1. The plastic waste is collected in bags or hopper from waste dumping yard.
  2. About 1 m3 (Weighing 40 to 50 kg) of plastic waste is put into the holding chamber of compaction / bale machine in two steps.
  3. The heating system is put on up to 5 minutes as required.
  4. The heating system is put off when plastics gets heated up to its softening point (50 to 600C)
  5. The hydraulic system is put on and compaction of heated plastics takes place.
  6. The volume gets reduced by 85 to 90% say from 1m3 to 0.15m3.
  7. The hydraulic cylinder is kept in place (compaction condition) and side doors opened.
  8. The wire is inserted to tie the compacted bundle mechanically too.
  9. The hydraulic cylinder is released and taken to initial position.
  10. The bale is taken out for storage. The plastics gets densified from 40 kg/m3 to 265 kg/m3

 

PLANT AND MACHINERY

 Hydraulically Operated Plunger type of Compaction Machine.

 Machine Size : 2 m x 2 m x 2.5 m

 

 

 CAPACITY OF MACHINE :


S.N.

Particular

Capacity

1.

Bulk density of loose plastics about

45kg/m3

2.

No. of trucks arrival with waste

40

3.

Capacity of each truck

200 cubic feet

4.

Total volumetric quantity of waste received

40 x 5.4

= 216 m3

5.

Total volumetric quantity of plastics waste received @20%volume

43.2m3

6.

Hold-up capacity of compaction machine

0.65m3

7.

Processing capacity of one cycle

1m3

8.

Cycle time of machine

10 mins.

9.

No. of cycles

6 per hrs.

10.

Volumetric quantity of waste compacted

6 m3 per hour

11.

Time required to handle total plastics with one machine

7 hrs.

 

RECOMMENDATIONS :

In the first phase 1 No. of machine be installed.

In the second phase 1 more machine should be installed.

 

ADVANTAGES

  1. The process is only for physical change of plastics from loose flying material to compact densified bale, hence environmental friendly.
  2. The nuisances of flying plastics is over come.
  3. Thermal and mechanical locking ensures compactness of bale during further transport.
  4. Further transportation cost is reduced to large extent.
  5. Value added dense plastic bale is produced from harmful nuisance causing municipal plastic waste.

 

LIMITATIONS

  1. Glass, Ceramics, metal pieces should be avoided to put in the system.
  2. Bio-medical / hazardous waste like insecticides should not be put in plastic waste reduction unit.
  3. Hydraulically operated system works at high pressure due safety precaution be taken.