REFUSE DISPOSAL SYSTEMAND

INSTALLATION

(INCINERATION)Presented By:

SHUAIBU ADAMU,PGS/15-16/4/D/4967

CONTENT

REFUSE DISPOSAL SYSTEMSOLID WASTE MANAGEMENTSOLID WASTESOURCES OF REFUSEHOW IT AFFECT HEALTHMETHOD OF DISPOSAL

INCINERATION

All nonhazardous solid waste from a community that requires collection and transport to a processing or disposal site is called refuse or municipal solid waste (MSW). 

Refuse disposal system, technique for the collection, treatment, and disposal of the solid wastes of a community. The development and operation of these systems is often called solid-waste management. (ENCYCLOPEDIA BRITANNICA)

REFUSE DISPOSAL SYSTEM

SOLID WASTE MANAGEMENT

Solid-waste management is the systematic control of generation, collection, storage, transport, source separation, processing, treatment, recovery and disposal of solid waste. (BusinessDictionary.com)

SOLID WASTES The term “solid wastes” includes:Garbage (food wastes) Rubbish (paper, plastics, wood, metal,

throw-away containers, glass), Demolition products (bricks, masonry,

pipes), Sewage treatment residue. Dead animals, manure and other

discarded material.

Sources of refuse

Sources of Refuse Cond’tRefuse that is collected by the street

cleansing service or scavenging is called street refuse.

Refuse that is collected from markets is called market refuse.

Refuse that is collected from stables is called stable litter.

Industrial refuse comprises a wide variety of wastes ranges from completely inert materials such as calcium carbonate to highly toxic and explosive compounds.

The domestic refuse consists of ash, rubbish and garbage.

HOW IT AFFECTS HEALTH? It decomposes and favors fly breeding It attracts rodents The pathogens may be conveyed back to

man’s food through flies and dust. Water and soil pollution, An unsightly apperance, bad odors. Incidence of vector- borne diseases.

METHODS OF DISPOSAL

The methods of waste disposal are: DumpingControlled Tipping or Sanitary Land-fill

Incineration Composting Manure Pits Burial

DUMPING

CONTROLLED TIPPING/ SANITARY LANDFILL

MECHANICAL COMPOSTING

COMPOSTING

MANURE PITS

BURIAL

INCINERATION

Incineration Cond’tMSW is burnt in a properly designed furnace

under suitable temperature and operating conditions. This process is called as incineration.

It is one of the most effective method of reducing the volume and weight of municipal solid waste.

The process consists of controlled burning of waste at high temp (1200- 1500°C).

It sterilizes and stabilizes the waste with reduction in the volume.

Incineration Cond’tIt is a process in which carbon, hydrogen and

other elements in the waste mix with oxygen in the combustion zone and generates heat. This reaction is called as oxidation.

For complete oxidation the waste must be mixed with appropriate volume of air. Approx. 5000kg of air is required for each tone of solid waste burned. It differs with moisture content, heating values of waste and type of combustion .

Proper temp must be maintained for suitable length of time.

Incineration Process

Incineration Process Cond’t

Incineration Process Cond’t

Incineration Cond’tThe process can reduce MSW by about

90% in volume and 75% in weight.

Temperature ensures good combustion and complete elimination of odour.

The combustion process is based on 3T’s1.Time2.Temperature3.Turbulence (gas velocity)

Objectives of Incineration1. Volume Reduction- To combust SW so as to

reduce their volume to 1/10th without producing offensive gases and ash.

Volume reduction depends upon the MSW composition. General volume reduction is by 90% and weight by 75%.

2. Stabilization of waste– output from incinerator is more inert than input due to oxidation of organic components of waste stream.

Objectives of Incineration Cond’t

3. Recovery of energy from waste – Energy recovered from burning of waste is used to generate steam for on site electricity generation or export to local heating schemes.

4. Sterilization of waste– Important for incineration of clinical/biomedical waste. It ensures pathogen destruction prior to final disposal.

Advantages of incineration Cond’t

The volume and weight of the waste are reduced to a fraction of its original size.

Waste reduction is immediate, does not require long term residence.

Waste can be incinerated on site without carted to a distant area.

Air discharge can be effectively controlled for minimal impact on the atmospheric environment.

Advantages of incineration Cond’tTechnology exists to completely destroy

even most hazardous material in a complete effective manner.

Requires relatively small disposal area compare to land burial. Particularly popular in countries such as Japan where land is a scarce resource.

By using heat recovery techniques the cost of operation can often be reduced or offset through the use or sale of energy.

Disadvantages of incineration

The capital cost is high.

Skilled operators are required.

All materials are not incinerable (construction and demolition waste).

Supplemental fuel is required to initiate and at times to maintain the incineration process.

Disadvantages of incineration Cond’t

The solid residue remaining in the furnace after incineration is called as bottom ash which ultimately go for land disposal. The bottom ash contain metals like lead which must be treated prior to disposal.

Health effects such as:Developmental of abnormalities in the

enamel of children's teeth.Damage to the immune systemsDiabetes

Disadvantages of incineration Cond’t

Fly ash is the incinerator ash carried along in the combustion airstream. So air pollution control devices are installed to remove fly ash and potentially harmful gaseous contaminants.

Thus, Installation of air pollution control equipment make the process expensive.

These equipments are located after the furnace and before the stack.

Important Factors For Incineration

1. waste moisture content– The greater the moisture content , more fuel is required to destroy the waste.

2. Heating Value–With no significant heating value incineration would not be a practical disposal method.

Important Factors For Incineration Cond’t

3. Inorganic salts– waste rich in inorganic, alkaline salts are troublesome to dispose off in a conventional incineration system.

4. High sulfur or halogen content– The presence of chlorides or sulfides in waste will normally result in the acid forming compounds in the off gas.

Technologies of incineration

The most diffused incinerators are of the type "to grates." The operation can be divided in 6 phases:

Arrival of the refusals Combustion Production of the vapor

overheated Production of energy electric Extraction of the ashes Treatment of the smokes

Arrival of the refusals

This are SW coming from the fittings of community selection displaced on the territory, the refusals are preserved in an area where the Incinerator is install endowed with a system of aspiration.

CombustionThe oven is endowed with one or

more grates to allow the continuous movement of the refusals. During the combustion, a tide of air will be inserted to reach a correct quantity of oxygen, maintaining tall the temperature. To maintain the time such temperatures is introduced with some gas methane.

Production of the overheated vapor

The strong issue of heat produced by the combustion of methane and refusals handed to vaporize the water in circulation is the boiler posts to valley, for the production of vapor overheated to tall that contained enthalpy.

Production of electric energy

The produced vapor is put in a movement turbine that joined with an alternator, it turns the thermal energy into electric energy producing alternating current.

Extraction of the ashes

The components of the non combustible refusals are picked up in a tub full with water posts at the valley of the last grate. The cinders cooled in this way, are drawn out and digest in special dumps.

Treatment of the smokes

After the combustion the warm smokes pass in a system fine-stadium of filtration, for the demolition of the content of polluting agents both chemists and solid.

After the treatment and the cooling the smokes are released in atmosphere to around 140°C.

Types of incinerators

Moving grate Fixed grate Rotary-kiln Fluidized bed

Moving grate

Fixed grate

Rotary-kiln

Fluidized bed

Thank You…..