Question

to justify and defend recommendation of solid waste management and sewerage characteristic,
treatment and its disposal according to standards/practices .

1.Problem statement:
People are facing lot of problems due to improper management of wastes (solid) as well as
unsuitable characteristics, disposal and treatment of sewerage wastes. Using the knowledge
of solid waste management, characteristics, treatment and disposal of sewerage, find
various parameters required for proper management of solid wastes as well as for
characteristics, treatment and disposal of sewerage wastes for your area.
2. Objectives of this Project:
Students should use their background knowledge about solid waste management and sewerage
characteristic, treatment and its disposal. They should prepare a report to ensure that all the
parameters are properly addressed and incorporated.

3. Report Format
The report should include the following sections:
4. Problem Definition/Identification:
This is a statement of the problem to be investigated. It provides overall direction for problem
understanding. The student should rephrase the stated problem in his own words that can display
his understanding of the problem.
5. Details of processes involved:
Students must provide all the details of processes involve in solid waste management and each
process must be clearly supported by steps necessary for performing them.
6. Propose Solution:
This is a statement which should provide a clear solution (solid waste management) to the problem.
7. Conclusions:
Discuss any questionable data or surprising results. Explain the possible source of any error or
questionable results, if applicable.

Note:

please make a report on it

Answer 1

With the planned landuses such as residential areas, industrial areas, commercial spaces, public amenities,green and open spaces and a total design population,people (comprising of

residents, employees and other floating population- direct and indirect), large quantities of solid wastes of

different characteristics are likely to be generated. The solid waste likely tobe generated will include domestic waste (general and hazardous waste), street sweeping waste, green

waste from landscaped areas, industrial waste (hazardous and non-hazardous), biomedical waste,

electronic waste (E) and Construction and Demolition (C&D)

Expected Waste Types and waste generating Sources

The solid waste generation would be mainly from following sectors:

Construction and Demolition waste: Waste generated during the construction of buildings,

infrastructure etc. and during demolition of any existing or temporary structure comprising cement

concrete, Bricks., Steel (from RCC structure, cutting & bending), Stone (stone pitching, stone masonry

etc.).

Residential: Waste generation from residential colonies such as dairy products, egg shells, fruit or

vegetable peels, paper, inert material such as plastic, metal, household hazardous waste such as

batteries Light bulbs, tube lights, CFLs, paints,

Commercial: Dry waste from commercial areas like shopping malls, Banks etc comprising packaging

material, food waste, plastic bottles, glass, metal scrap

Institutional: Solid waste such as paper, plastic, e-wastes, detergents, canteen waste, cardboard from

educational institutions, other similar facilities like schools and colleges.

Biomedical waste: Biomedical waste, general non-hazardous waste, municipal waste from hospitals

Industrial Waste: Hazardous and non-hazardous industrial solid waste such as solvents, used oils,

Sludge, discarded containers/barrels/liners contaminated with hazardous wastes/chemicals, packaging

material, paper cardboard, etc.

Street sweeping and garden waste including sewage sludge: Small amount of waste would be

generated from street and road sweepings and garden waste.

E-waste: Some electronic waste will also be generated during the operation of the scheme from

institutional areas, administrative areas and domestic household.

Waste Quantification for Construction phase

The waste generation during construction phase will include construction waste and residential waste from

labor colonies. The construction waste will largely comprise earth, stones, concrete, bricks, lumber, roofing

materials, plumbing materials, electrical wires etc. Major and minor components of construction waste may

be categorized as follows:

Major components:

Cement concrete, Bricks, Cement plaster, rubble

Steel (from RCC, door/window frames, roofing support, railings of staircase etc.)

Stone (marble, granite, sand stone)

Minor components:

Conduits (iron, plastic), Pipes (Galvanized iron (GI), iron, plastic)

Electrical fixtures (copper/aluminium wiring, Bakelite/plastic switches, wire insulation)

Panels (wooden, laminated), Others (glazed tiles, glass panes)

Domestic waste from Labour Camps/ Colonies:

The waste from the labour colonies will mainly comprise municipal waste and sewage from the toilets.

The waste envisaged from labour colonies residing temporarily during construction phase has been

estimated based on approximate labour population that would be engaged during development

the labour colonies will mainly comprise of:

Municipal waste comprising of wet organic waste kitchen waste and inorganic dry recyclables such as

plastics, paper, glass bottles etc.

Sewage from the toilets

Municipal Solid Waste Management

Storage: Considering the type of waste likely to be generated from the construction and operation, adoption

of a two-bin system (generally for dry and wet waste segregation) for storage at source is being analysed.

Waste segregation basically means keeping wet and dry wastes separately, so that dry can be recycled and

wet waste (organic in nature) can be composted. Detailing shall be done at preliminary engineering stage

providing details such as number, colour coding, type, technical specification, etc.

As policy, the industry owner shall be responsible for safe and environmentally sound handling of hazardous

wastes generated in his establishment.

Waste Collection and Transportation (C&T): Segregated waste collection of waste shall be adopted, using

specially designed vehicles. All the vehicles to be used for C&T of waste shall have vehicle tracking system

installed in them for continuous monitoring of waste collection frequency, routing, areas serviced.

A combination of door-to-door collection, kerbside collection, setting up interim waste transfer points using

mini tipper vehicles, refuse compactor trucks capable of lifting waste trolley bins, static compactors shall

ensure efficient waste C&T. Municipal waste shall be collected from plot level, using smaller vehicles such

as mini-tipper autos. The wastes will be transferred to larger vehicles at identified secondary waste collection

points within the residential areas, which shall transport the waste to the proposed Integrated Waste

Management Facility.

Non-hazardous industrial wastes shall be recycled and reused as far as possible and the rest shall be sold to recyclers.

Recommended Components of Integrated Solid Waste Management Facility

(for Municipal Waste)

For municipal solid waste processing and disposal, it is recommended to set up an Integrated Solid Waste

• Waste Receiving and Storage Yards
• Segregation plant-cum-Material Recovery Facility
• Bio-methanation Plant
• Sanitary Landfill for inerts and other non-usable reject waste
• Other allied infrastructure (Greenbelt, admin block, parking, power substation, workshop, chemical
• testing laboratory, internal roads, storm water drainage, leachate collection network and sumps)

Waste Receiving and Storage Yards:

Waste will be received from following Municipal bins:

i Community level twin waste trolley bins.

These will be located in market areas, commercial

complex, office areas and industrial areas (for municipal

wastes).

Sanitary Landfill for inerts and other non-usable reject waste

It is recommended to construct a sanitary landfill for disposal of inerts and other rejects from other abovementioned

waste processing plants. Maximum efforts will be made to divert wastes from reaching the landfill

by adopting waste management strategies

Definitions of technical terms used in solid
and liquid waste management

Ashes: residue from fires used for cooking and heating  
Biodegradable: capable of being breakdown by biological

process.

Biodegradation: metabolic process by which high energy

organics are converted to low energy, CO₂, and H₂O
Biological Oxygen Demand (BOD): amount of oxygen, used

by microorganisms in the biodegradation process.

Bulky Refuse: materials that are non-combustible including

metals cans furniture dirt glass. etc.

Decomposition: reduction of net energy level and change in

chemical composition of organic matter because of
actions of aerobic or anaerobic microorganisms.  

Dumping: The final disposal of all refuses by uncontrolled,
indiscriminate deposition on sand areas, in pits or
quarries, rivers, etc.

Effluent: out flowing liquid and broken by the action of
anaerobic bacteria.

Garbage: Organic and generally biodegradable wastes from the preparation and processing of foods in homes,

Garden trash: Grass clippings, flowers, shrubbery and tree
trimmings, leaves, and other tree droppings.

Influent: inflowing liquid

Municipal wastes: normal sized wastes from street cleaning

and    litter collections from playgrounds, schools,
hospitals, parks, dead animals and public slaughtering
house.  

Recyclable (salvageable): Materials or items which can
economically sorted out and removed from refuse for
sale, refuse by private enterprise.

Residues: Solid material which is left (discharged) at the end
of burning (incineration)

Rubbish: combustible wastes including paper, card board
boxes, barrels, wood, tree branches yard trimmings,
furniture originating from homes institutions hotels,
markets, Stores, etc.  

Sewage disposal: the act of disposing sewage by any means. Sewage treatment: covers any process in which sewage is

subjected in order to remove or alter its objectionable
constituent to make it less dangerous or offensive.

Sewer: a pipe containing sewage or wastewater

Sewerage: a system of sewer pipes for collecting sewage or
wastewater into the treatment and disposal.

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

Street Refuse: street-sweeping dirt.

Sullage: domestic dirty water not combined with excreta

Background Information

Domestic Waste is waste, which is either solid or liquid generated in residential areas, Commercial settings and institutions. Waste in general terms is defined as an unwanted as it is obviously undesirable. It is nevertheless an inevitable and inherent product of social, economic and cultural life.

The indiscriminate disposal of waste, both liquid and solid, adversely affects the immediate human environment by degrading the natural phenomena hence, exerting health risk to exposed population. Health risks may be carried through different vehicles including flies, dogs, rodent and others that scavenge on the waste.

In this lecture note, the most practical ways of managing solid and liquid waste at household and community levels are discussed in detail. However, considerable emphasis is given to solid waste management systems. The various technologies for proper disposal of solid wastes are listed.

This lecture note is basically aimed at health extension students and community promoters to provide a ready-made reference, but other primary health workers can also use it. The lecture note has three main chapters namely, solid waste management, liquid waste management and contaminated waste management.   

UNIT ONE

Solid Waste Management

Learning Objectives

After completing this unit the trainee will be able to:

Define solid Waste Management.  

Describe public health importance of Solid Waste.

Describe the major sources and types of Solid Waste

Demonstrate common Solid Waste disposal methods.

1.1 Introduction  

Solid waste management: A systematic administration of activities that provide for the collection, source separation, storage, transportation, transfer, processing, treatment and disposal of solid waste.

1.2 Public Health importance of solid waste  

It can be best media for the growth of microorganisms

Attraction of arthropods such as common housefly,

mosquito, etc  

Attraction of rodents and other animals e.g. rats mice

dogs cats

                                                 

Open dump can contaminate water sources

Can contaminate food supply and cause food borne

disease  

Hospital and pathological wastes are potential disease

carrying waste products

Radioactive wastes are highly dangerous  

It can create fire accident  

Slum areas

It can create nuisance:

Bad odor, smoke, dust  
Aesthetical problem  

Discomfort: sneezing, coughing  

1.3 Classifications of solid waste

Solid waste can be classified into two categories by its characteristics. These are:

Organic solid waste

Inorganic Solid waste

Organic solid waste: Wastes                                                                   that are generally biodegradable and decompose in the process of which emits offensive and irritating smell when left unattended.  

⇒ Putrescible wastes e.g. Garbage

                                                 

Inorganic solid waste: Solid matter that does not decompose at any rate This category of waste matter may be combustible depending on the type of the nature of the material they constitute.

Non-putrescible wastes e.g. Rubbish

1.4 Functional Elements of solid waste
management system

There are six functional elements in the activities associated with the management of solid wastes from the point of generation to final disposal site. These are:  

1. Waste generation  

2. On-site handling (sorting, storage and processing)  
3. Collection  

4. Transfer and transport  

5. Processing and recovery  

6. Disposal  

Description of the six main functional elements of solid waste management system:

Waste generation: those activities in which materials are identified as no longer being of value and are either thrown away or gathered together for disposal.

                                                 

On-site handling, storage, and processing: activities associated with the handling, storage, and processing of solid wastes at or near the point of generation.   

Collection: those activities association with the gathering of solid wastes and the hauling of wastes to the location where the collection vehicle is emptied.

Transfer and transport: Those activities association with (1) the transfer of wastes from the smaller collection vehicle to the larger transport equipment and (2) the subsequent transport of the wastes, usually over long distance, to the disposal site.

Processing and recovery: Those techniques equipment and facilities used both to improve the efficiency of the other functional elements and to recover useable materials, conversion products, or energy from solid wastes.

Disposal: Those activities associated with ultimate disposal of solid wastes

Interrelationship of functional elements comprising a solid waste management system.

1.5 Main sources of solid waste generation

Residential (domestic or house hold)
Commercial

       Institutional  

Construction Demolition   

Treatment plant sites

       Industrial   

Agricultural   

                                                 

1.6 Waste handling and separation, storage
and processing at the source  

The best place to separate waste materials for reuse and
recycling is at the source of generation  

Home owners should be aware of separation of News
paper, and cardboard, bottles, yard wastes, aluminum
cans, ferrous materials and especially hazardous wastes  

Waste processing is used to   reduce the volume, recover
usable materials, and alter the physical form of the solid
wastes.

The most common on-site processing operations used are:

Food waste grinding and release to sewer system  

Component separation  

Compaction: decrease the volume up to 70%  

       Incineration, yard waste composting etc

1.7 Solid waste collection   

Collection     is provided under various management pattern/arrangements:

Municipal/Rural Communities Organization- using simple
and locally available technology such as Donkey Drawn
Cart

Private services such as contractors

Scavenger system: Individuals may collect and use

                                                

wastes like paper, metal, containers, clothes etc for reuse or recycling.  

Frequency of collection: should be considered to avoid fly breeding and for aesthetic consideration  

Garbage: at least 2 times /week in residential areas  

Rubbish: weekly in residential areas  

Mixed refuse: at least 2 times/week in residential areas

N.B. All wastes should be collected daily in commercial areas.

Time of Collection:   

Residential areas: during the daytime, because of noise nuisances and difficulty of locating storage
containers in the dark.

                                                

Commercial areas: during nighttime because of
heavy traffic during day for large collection truck

Influencing factors of collection:
Type of equipment:

                        Vehicle
                        Pushcart

Maintenance services for equipment
                        Garage
            Workshop

Number and capacity of equipments

Site and accessibility of collection situations

Cost and routing of collection

Number of crewmen

Community involvements/participations

Intermediate treatment and final disposal site distance

1.8 Recycling and reuse

Reuse and recovery/recycling of waste conserves energy and the practice is valued as it is environmental friendly. Waste products such as the non-decomposable ones, which include broken glasses, metal scraps, wires and the licke, can be recovered for further processing. Some materials can also be

recovered for reuse with out further processing. There are different ways and practices of converting wastes in to useful assets. For example:

Human or animal urine contains the element nitrogen,
which is used as fertilizers. Farmers in rural Ethiopia
use manure and other waste for fertilizer.

Animal bones can be made to be a very important
animal feed after processing.

Rural communities know and use dung for plastering
of houses and as an energy source for open fire
burning.

Some people in bigger towns in Ethiopia collect
bottles, old shoes, clothes, metal products, which is
one form of recycling or reuse.

In general, waste recovery and reuse is economically and socially feasible and acceptable.

1.9 Common solid waste disposal methods  

In rural communities the following common useful simple and practical methods of solid waste intermediate treatments/reuse and disposal methods include:

Composting

                                                

Controlled Tipping/Burying Ploughing in the Fields

      Incineration

1.9.1 Composting

Composting is one of the means of waste minimization. The mechanism implies a biological waste treatment process. The action of microorganisms breaks down complex organic compounds into simpler ones.

Composting is not final disposal method but converting waste into a useful product. Compost has been used in both the rural and semi urban areas of Ethiopia for quite a long time as a soil conditioner to grow mostly vegetables and crops but without processing it.

Composting process:

1. Sort and/or separate the compostable organic matter such

as garbage, grass, dung, etc from the uncompostable ones
such as plastic, leather, ceramic, clay or metal products that
hamper the decomposition process.

2. Mix in equal proportion all wastes including animal manure,
kitchen waste, weeds and house sweepings. It may be
necessary to add and mix human and animal waste to

                                                

enhance and facilitate the biodegradation process. Adding
these waste matters not only enhances the decomposition
process but it also enriches the waste in nitrogen and
phosphorous. Which are essential elements for plant
growth. However, using human or animal waste need
precautions as it may contain pathogenic organisms, which
may contaminate the crops, the hand and feet of people
working in the farm. This may create a perpetual
communicable disease transmission condition outweighing
the advantage of waste reuse.

3. Compost sites may be arranged by digging a shallow hole
the size of which may vary with the amount of waste
intended to be composted or the waste may be place above
ground. Placing it above ground is easier to work with the
waste in the process of composting.

4. Pile the sorted and mixed solid waste on the ground to a
height of about 0.15 meters (15 centimeters). Lay
horizontally four round sticks on top of the pile as shown in
figure 3. The space in between the poles could be from 75-
90 cm.

7. Cover the completed pile of waste with 50 cm earth and
animals manure and take out the poles from the pile as
shown in figure 5.   

The soil/manure cover will help in preventing rainwater from soaking into the pile. Reduce evaporation, lessen loss of nitrogen (nutrient), prevents fly breeding etc. The holes made by the poles will help in introducing oxygen into the pile hence making the composting process aerobic. Such method will not cause nuisance or smell.

Instead of using round wooden poles the waste could be
piled up as it is and aerate it once or twice a week by
turning it so that aerobic bacteria can remain active and
proliferate and stabilize the waste.

                                                

Well-stabilized compost is:  
                        Dark looking  
                        Does not smell and                      Stable humus

The compost supplies the elements that plants require for
growth except some deficiencies in phosphorous and
nitrogen. This may be improved by adding urine together
with the humus.

1.9.2 Controlled Tipping/Burying

Solid wastes that are not recycled or used should be disposed.   Disposal is effected in many different ways. But the most important method is that which is able to isolate the waste for good. A method that satisfies this is known as controlled tipping. It is a way of isolating any type of waste without bothering to sort or separate.

Controlled tipping is a simple, effective and relatively cheaper method of refuse disposal. This method involves preparation of hole in the ground with a depth of 1-2 meters and width and length of 60 centimeters for a household. The method can be used as a one-time or a daily operation. If it is a daily operation the process is as follows:

                                                

1. A disposal site is identified within the compound of any
residential, commercial or institutions. The site should not
be:

Near water sources

Near to houses and kitchen
Near a road or path

2. Pile the dugout earth near the pit for future use

3. Dump the generated solid waste (garbage, refuse etc) in the

pit daily

4. Cover the waste matter with the excavated soil every day

Waste generated every day is dumped into the pit and covered with earth so that flies and vermin don't get access to it. The process continues until the pit is filled after which it should be completely covered with earth and another one is dug next to the old one. With this method flies, mosquitoes, rodents, wild animals, birds and other nuisance animals will not have access to breed and feed.

The decomposable waste will still condition the soil. Crops planted on completed sites grow better and the immediate surrounding of the dwelling house looks always clean.

1.9.3 Incineration

Incineration is a high temperature dry oxidation process that reduces organic and combustible waste to                                                                                     inorganic, incombustible matter and resulting in a very significant reduction of waste volume and weight.

Characteristics of wastes suitable for incineration:

Content of combustible matter above 60%

Content of non-combustible solids below 5%
Content of non-combustible fines below 20%
Moisture content below 30%  

                                                

Waste types not to be incinerated:

Pressurized gas containers  

Large amount of reactive chemical waste  

Silver salt and photographic or radiographic wastes  
Halogenated plastics such as polyvinyl chloride

(PVC)  

Waste with high mercury or cadmium content, such

as broken thermometers, used batteries, and lead-
lined wooden panels   

Sealed ampoules or ampoules containing heavy
metals  

⇒ Air pollution is undesirable characteristics of
incinerator  

⇒ Expensive and skill personnel is needed  

⇒ May be located close to centre of waste

production (advantageous)

Types of Incinerators

Incinerator can range from extremely sophisticated; high- temperature once to very basic that operate at much lower temperatures. All types of incinerators, if operated properly, eliminate microorganisms from waste and reduce the waste to ashes.

At a small community with the limited resources and where

                                                

high-temperature incinerators are not affordable, waste may be incinerated in a drum incinerator. A drum incinerator is the simplest form of single-chamber incinerator figure 7 & 8. It can be made inexpensively and is better than open burning.

How to build and use a simple drum incinerator for waste disposal:

Step 1: where possible, select a site downwind from the health
post.

Step 2: Build a simple incinerator using local materials (mud
or stone) or a used oil drum (e.g., 80-100 liters drum).
The size depends on the amount of daily waste
collected (figure 7).

Step 3: Make sure the incinerator has:

Sufficient air inlets underneath for good combustion

Loosely placed fire bars to allow for the expansion

An adequate opening for adding fresh refuse and for

removal of ashes

A long enough chimney to allow for a good draft and

evacuation of smoke.

Step 4: Place the drum on hardened earth or a concrete base.

                                                

Step 5: Burn all combustible waste, such as paper and
cardboard, as well as used dressings and other
contaminated wastes. If the waste or refuse is wet,
add kerosene so that a hot fire burns all the waste.
Ash from incinerated material can be treated as non-
contaminated waste.