Unit v Reuse and Recycle

SRES’S Sanjivani College of Engineering, Kopargaon
(An Autonomous Institute)
UNIT V
REUSE AND RECYCLE
5.1 Importance of Recycling & Reuse
Recycling is one of the best ways for you to have a positive impact on the world in which we
live. Recycling is important to both the natural environment and us. We must act fast as the
amount of waste we create is increasing all the time.
The amount of rubbish we create is constantly increasing because:
Increasing wealth means that people are buying more products and ultimately creating more
waste.
Increasing population means that there are more people on the planet to create waste.
New packaging and technological products are being developed, much of these products contain
materials that are not biodegradable.
New lifestyle changes, such as eating fast food, means that we create additional waste that isn’t
biodegradable.
Environmental Importance
Recycling is very important as waste has a huge negative impact on the natural environment.
Harmful chemicals and greenhouse gasses are released from rubbish in landfill sites. Recycling
helps to reduce the pollution caused by waste.
Habitat destruction and global warming are some the affects caused by deforestation. Recycling
reduces the need for raw materials so that the rain forests can be preserved.
Huge amounts of energy are used when making products from raw materials. Recycling requires
much less energy and therefore helps to preserve natural resources.
Importance To People
Recycling is essential to cities around the world and to the people living in them. No space for
waste. Our landfill sites are filling up fast, by 2010, almost all landfills in the UK will be full.
Reduce financial expenditure in the economy.
Making products from raw materials costs much more than if they were made from recycled
products.
Environmental Science (Audit Course)1
Prepared By: Dr. M.V. Jadhav
Prof. U.T. Kulkarni

Preserve natural resources for future generations. Recycling reduces the need for raw materials; it
also uses less energy, therefore preserving natural resources for the future.
5.2 Reuse and Recycling of MSW
MSW includes commercial and residential wastes generated in municipal or notified areas in
either solid or semi-solid form excluding industrial hazardous wastes but including treated bio-
medical wastes. It consists of household waste, wastes from hotels and restaurants, construction
and demolition debris, sanitation residue, and waste from streets.
Recycling is the recovery and reuse of materials from wastes. Solid waste recycling refers to
the reuse of manufactured goods from which resources such as steel, copper , or plastics can be
recovered and reused. Recycling and recovery is only one phase of an integrated approach to
solid waste management that also includes reducing the amount of waste produced, composting ,
incinerating, and landfilling.
MSW Generation in India
As per estimates more than 55 million tons of MSW is generated in India per year; the yearly
increase is estimated to be about 5%. It is estimated that solid waste generated in small, medium
and large cities and towns in India is about 0.1 kg, 0.3 – 0.4 kg and 0.5 kg per capita per day
respectively. The estimated annual increase in per capita waste generation is about 1.33 % per
year.
Composition of MSW Generated in Indian Cities
In India, the biodegradable portion dominates the bulk of MSW. This is mainly due to food
and yard waste. With rising urbanization and change in lifestyle and food habits, the amount of
municipal solid waste has been increasing rapidly and its composition has been changing.
Recycling is a significant way to keep large amounts of solid waste out of landfills, conserve
resources, and save energy. As of now total 30.1% of MSW recovered, recycled, or composted,
incinerated 14.5%, and landfilled 55.3%.
The technology of recycling involves collection, separation, preparing the material to buyer's
specifications, sale to markets, processing, and the eventual reuse of materials. Separation and
collection is only the first step; if the material is not also processed and returned to commerce,
then it is not being recycled. In many parts of the country, markets are not yet sufficiently
developed to handle the growing supply of collected material.
Prof. U.T. Kulkarni

Intermediate markets for recyclable materials include scrap dealers or brokers, who wait for
favorable market conditions in which to sell their inventory. Final markets are facilities where
recycled materials are converted to new products, the last phase in the recycling circle.
Fig 1. MSW Composition in India
MSW Management in India
A typical waste management system in India includes the following elements:
1. Waste generation and storage
2. Segregation, reuse, and recycling at the household level
3. Primary waste collection and transport to a transfer station or community bin
4. Street sweeping and cleaning of public places
5. Management of the transfer station or community bin
6. Secondary collection and transport to the waste disposal site & Waste disposal in landfills
Fig 2. MSW Collection & Conveyance
Prof. U.T. Kulkarni

In most of the Indian cities, the MSW collection, segregation, transportation, processing and
disposal is carried out by the respective municipal corporations and the state governments
enforce regulatory policies, but wherein most of the Indian cities open dumping is the common
practice which is adversely affecting on environment and public health.
The major stakeholders in the management of Municipal Solid Waste include: (a) Ministry of
Environment and Forests (MoEF) (b) Ministry of Urban Development (MoUD) (c) Central and
State Pollution Control Boards (d) Department of Urban Development (e) State Level Nodal
Agency (f) Urban Local Bodies (g) Private Formal and informal Sector.
In some cities like Mumbai, Chennai, Delhi, Bengaluru, Hyderabad and Ahmedabad garbage
disposal is done by Public Private Partnerships (PPPs). The private sector has been involved in
door-to-door collection of solid waste, street sweeping (in a limited way), secondary storage and
transportation and for treatment and disposal of waste.
Urban Local Bodies spend around Rs.500 to Rs.1500 per ton on solid waste management of
which, 60-70% of the amount is on collection alone, 20% - 30% on transportation, but hardly any
fund is spent on treatment and disposal of waste
Potential for Energy Generation from MSW
The total estimated potential for power from all MSW across India is about 1457 MW
(2002). MNRE estimates the energy recovery potential from municipal solid wastes to be about
1500 MW and this could go up to 5,200 MW by 2017. These trends have made many state
governments keen on tapping this source of energy.
Technological Routes for Energy Generation from MSW
Energy can be recovered from the organic fraction of waste (biodegradable as well as non-
biodegradable) through thermo-chemical and biochemical methods.
5.2.1 Methods of Recycling of MSW
I. Decentralized SWM
II. Awareness in Reuse and Recycle
III. Using MSW for creating energy such as RDFs
IV. PAYT system (Pay as You Through) must be implemented
Prof. U.T. Kulkarni

V. Creating awareness among public on SWM
5.3 Reuse and Recycle of Sewage
Reclaimed or recycled water (also called wastewater reuse or water reclamation) is the
process of converting wastewater into water that can be reused for other purposes. Reuse may
include irrigation of gardens and agricultural fields or replenishing surface water and
groundwater (i.e., groundwater recharge). Reused water may also be directed toward fulfilling
certain needs in residences (e.g. toilet flushing), businesses, and industry, and could even be
treated to reach drinking water standards. This last option is called either "direct potable reuse" or
"indirect potable" reuse, depending on the approach used. Colloquially, the term "toilet to tap"
also refers to potable reuse.
Reclaiming water for reuse applications instead of using freshwater supplies can be a water-
saving measure. When used water is eventually discharged back into natural water sources, it can
still have benefits to ecosystems, improving stream flow, nourishing plant life and recharging
aquifers, as part of the natural water cycle.
Wastewater reuse is a long-established practice used for irrigation, especially in arid
countries. Reusing wastewater as part of sustainable water management allows water to remain as
an alternative water source for human activities. This can reduce scarcity and alleviate pressures
on groundwater and other natural water bodies.
Achieving more sustainable sanitation and wastewater management will require emphasis on
actions linked to resource management, such as wastewater reuse or excreta reuse that will keep
valuable resources available for productive uses. This in turn supports human wellbeing and
broader sustainability.
Simply stated, reclaimed water is water that is used more than one time before it passes back
into the natural water cycle. Advances in wastewater treatment technology allow communities to
reuse water for many different purposes. The water is treated differently depending upon the
source and use of the water and how it gets delivered.
Cycled repeatedly through the planetary hydrosphere, all water on Earth is recycled water,
but the terms "recycled water" or "reclaimed water" typically mean wastewater sent from a home
or business through a sewer system to a wastewater treatment plant, where it is treated to a level
consistent with its intended use.
Prof. U.T. Kulkarni

Categories of
use
Uses
Urban uses
Irrigation of public parks, sporting facilities, private gardens, roadsides; Street
cleaning; Fire protection systems; Vehicle washing; Toilet flushing; Air
conditioners; Dust control.
Agricultural
uses
Food crops not commercially processed; Food crops commercially processed;
Pasture for milking animals; Fodder; Fibre; Seed crops; Ornamental flowers;
Orchards; Hydroponic culture; Aquaculture; Greenhouses; Viticulture.
Industrial uses Processing water; Cooling water; Recirculating cooling
The World Health Organization has recognized the following principal driving forces for
wastewater reuse:
a. increasing water scarcity and stress,
b. increasing populations and related food security issues,
c. increasing environmental pollution from improper wastewater disposal, and
d. Increasing recognition of the resource value of wastewater, excreta and greywater.
Water recycling and reuse is of increasing importance, not only in arid regions but also in
cities and contaminated environments.
Already, the groundwater aquifers that are used by over half of the world population are
being over-drafted. Reuse will continue to increase as the world's population becomes
increasingly urbanized and concentrated near coastlines, where local freshwater supplies are
limited or are available only with large capital expenditure. Large quantities of freshwater can be
saved by wastewater reuse and recycling, reducing environmental pollution and improving
carbon footprint. Reuse can be an alternative water supply option.
5.3.1 Types of Reuse and Application of Sewage
Table 1. Types of Reuse of sewage
Prof. U.T. Kulkarni

Prof. U.T. Kulkarni
towers; Washdown water; Washing
compaction; Dust control.
aggregate; Making concrete; Soil
Recreational
uses
Golf course irrigation; Recreational impoundments with/without public access
(e.g. fishing, boating, bathing); Aesthetic impoundments without public access;
Snowmaking.
Environmental
uses
Aquifer recharge; Wetlands; Marshes;
habitat; Silviculture.
Stream augmentation; Wildlife
Potable uses
Aquifer recharge for drinking water use; Augmentation of surface drinking
water supplies; Treatment until drinking water quality.
5.3.2 Methods of Recycling of Sewage
Wastewater treatment and reuse is an important issue and scientists are looking for
inexpensive and suitable technologies. Water treatment technologies are used for three purposes
i.e. water source reduction, wastewater treatment and recycling. At present, unit operations and
processes are combined together to provide what is called primary, secondary and tertiary
treatment. Primary treatment includes preliminary purification processes of a physical and
chemical nature while secondary treatment deals with the biological treatment of wastewater.
In tertiary treatment processes, wastewater (treated by primary and secondary processes) is
converted into good quality water that can be used for different types of purpose, i.e. drinking,
industrial, medicinal etc. supplies. In the tertiary process, up to 99% of the pollutants are removed
and the water is converted into the safe quality for a specific use. In a complete water treatment
plant, all these three processes are combined together for producing good quality and safe water.

Fig 2. Methods of Recycling of Sewage
Despite the development of various technologies for water treatment and reclamation,
economic, effective and rapid water treatment and reclamation at a commercial level is still a
challenging problem. The management of the removed pollutants (sludge) should be kept in
mind. The systematic approach of water treatment and recycling technologies involves the
understanding of the technology that includes construction and operational cost, along with the
maintenance and management of removed pollutants.
5.4 Reuse and Recycle of E-Waste
Electronic waste or e-waste describes discarded electrical or electronic devices. Used
electronics which are destined for refurbishment, reuse, resale, salvage recycling through material
recovery, or disposal are also considered e-waste. Informal processing of e-waste in developing
countries can lead to adverse human health effects and environmental pollution. With the usage of
electrical and electronic equipment (EEE) on the rise, the amount of electrical and electronic
waste (e-waste) produced each day is equally growing enormously around the globe.
Prof. U.T. Kulkarni

1. Effects of E-Waaste
Disposal of e-wastes is a particular problem faced in many regions across the globe.
Computer wastes that are landfilled produces contaminated leachates which eventually pollute
the groundwater. Acids and sludge obtained from melting computer chips, if disposed on the
ground causes acidification of soil. For example, Guiyu, Hong Kong a thriving area of illegal e-
waste recycling is facing acute water shortages due to the contamination of water resources.
This is due to disposal of recycling wastes such as acids, sludges etc. in rivers. Now water is
being transported from faraway towns to cater to the demands of the population. Incineration of
e-wastes can emit toxic fumes and gases, thereby polluting the surrounding air. Improperly
monitored landfills can cause environmental hazards. Mercury will leach when certain electronic
devices, such as circuit breakers are destroyed. The same is true for polychlorinated biphenyls
(PCBs) from condensers. When brominated flame retardant plastic or cadmium containing
plastics are landfilled, both polybrominated dlphenyl ethers (PBDE) and cadmium may leach into
the soil and groundwater. It has been found that significant amounts of lead ion are dissolved
from broken lead containing glass, such as the cone glass of cathode ray tubes, gets mixed with
acid waters and are a common occurrence in landfills.
Not only does the leaching of mercury poses specific problems, the vaporization of metallic
mercury and dimethylene mercury, both part of Waste Electrical and Electronic Equipment
(WEEE) is also of concern. In addition, uncontrolled fires may arise at landfills and this could be
a frequent occurrence in many countries. When exposed to fire, metals and other chemical
substances, such as the extremely toxic dioxins and furans (TCDD tetrachloro dibenzo-dioxin,
PCDDs-polychlorinated dibenzodioxins. PBDDs-polybrominated dibenzo-dioxin and PCDFspoly
chlorinated dibenzo furans) from halogenated flame retardant products and PCB containing
condensers can be emitted. The most dangerous form of burning e-waste is the open-air burning
of plastics in order to recover copper and other metals. The toxic fall-out from open air burning
affects the local environment and broader global air currents, depositing highly toxic byproducts
in many places throughout the world.
2. Methods of Management of E-Waste
In industries management of e-waste should begin at the point of generation. This can be
done by waste minimization techniques and by sustainable product design. Waste minimization in
industries involves adopting:
• Inventory management,
Prof. U.T. Kulkarni

• Production-process modification,
• Volume reduction,
• Recovery and reuse.
Inventory management
Proper control over the materials used in the manufacturing process is an important way to
reduce waste generation (Freeman, 1989). By reducing both the quantity of hazardous materials
used in the process and the amount of excess raw materials in stock, the quantity of waste
generated can be reduced. This can be done in two ways i.e. establishing material-purchase
review and control procedures and inventory tracking system.
Developing review procedures for all material purchased is the first step in establishing an
inventory management program. Procedures should require that all materials be approved prior to
purchase. In the approval process all production materials are evaluated to examine if they
contain hazardous constituents and whether alternative non-hazardous materials are available.
Production-process modification
Changes can be made in the production process, which will reduce waste generation. This
reduction can be accomplished by changing the materials used to make the product or by the
more efficient use of input materials in the production process or both. Potential waste
minimization techniques can be broken down into three categories:
i) Improved operating and maintenance procedures,
ii) Material change and
iii)Process-equipment modification.
Recovery and reuse
This technique could eliminate waste disposal costs, reduce raw material costs and provide
income from a salable waste. Waste can be recovered on-site, or at an off-site recovery facility, or
through inter industry exchange. A number of physical and chemical techniques are available to
reclaim a waste material such as reverse osmosis, electrolysis, condensation, electrolytic
recovery, filtration, centrifugation etc. For example, a printed-circuit board manufacturer can use
electrolytic recovery to reclaim metals from copper and tin-lead plating bath.
Sustainable product design
Minimization of hazardous wastes should be at product design stage itself keeping in mind
the following factors
Prof. U.T. Kulkarni

• Rethink the product design
• Use of renewable materials and energy
• Use of non-renewable materials that are safer
5. Reuse and Recycle of C&D Waste
Construction and demolition (C&D) waste is generated from construction, renovation, repair,
and demolition of houses, large building structures, roads, bridges, piers, and dams. C&D waste is
made up of wood, steel, concrete, gypsum, masonry, plaster, metal, and asphalt.
Construction and demolition (C&D) materials are generated when new building and civil-
engineering structures are built and when existing buildings and civil-engineering structures are
renovated or demolished (including deconstruction activities). Civil-engineering structures
include public works projects, such as streets and highways, bridges, utility plants, piers, and
dams.
C&D materials often contain bulky, heavy materials such as:
• Concrete
• Wood (from buildings)
• Asphalt (from roads and roofing shingles)
• Gypsum (the main component of drywall)
• Metals
• Bricks
• Glass
• Plastics
• Salvaged building components (doors, windows, and plumbing fixtures)
• Trees, stumps, earth, and rock from clearing sites
1. Benefits of Reducing the Disposal of C&D Materials
Reducing the amount of C&D materials disposed of in landfills or incinerators can:
• Create employment and economic activities in recycling industries and provide increased
business opportunities within the local community, especially when deconstruction and
selective demolition methods are used.
• Reduce overall building project expenses through avoided purchase/disposal costs, and
the donation of recovered materials to qualified charities, which provides a tax benefit.
Onsite reuse also reduces transportation costs.
• Lead to fewer disposal facilities, potentially reducing the associated environmental issues.
Prof. U.T. Kulkarni

• Offset the environmental impact associated with the extraction and consumption of virgin
resources and production of new materials.
• Conserve landfill space.
5.5.2 Methods to Reduce, Reuse and Recycle C&D Materials
1.Source reduction: reduces life-cycle material use, energy use and waste generation. EPA gives it
the highest priority for addressing solid waste issues. While reuse and recycling are important
methods to sustainably manage waste once waste has already been generated, source reduction
prevents waste from being generated in the first place.
Examples of C&D source reduction measures include preserving existing buildings rather
than constructing new ones; optimizing the size of new buildings; designing new buildings for
adaptability to prolong their useful lives; using construction methods that allow disassembly and
facilitate reuse of materials; employing alternative framing techniques; reducing interior finishes;
and more.
Salvaging and Reusing of C&D Materials: Demolishing existing buildings and disposing of the
debris is not a resource efficient practice. Recovering used, but still-valuable C&D materials for
further use is an effective way to save money while protecting natural resources.
Deconstruction for Reuse
Deconstruction is the process of carefully dismantling buildings to salvage components for reuse
and recycling. Deconstruction can be applied on a number of levels to salvage usable materials
and significantly cut waste.
Deconstruction has many benefits, including the following:
• Maximizes the recovery of materials.
• Conserves finite, old-growth forest resources.
• Provides many employment and job training opportunities.
• When coupled with traditional demolition methods, allows communities to create local
economic activities around manufacturing or reprocessing salvaged materials.
• Diverts demolition debris bound for disposal
• Preserves resources through reuse.
3. Recycling C&D Materials:
Prof. U.T. Kulkarni

Many building components can be recycled where markets exist. Asphalt, concrete, and rubble
are often recycled into aggregate or new asphalt and concrete products. Wood can be recycled
into engineered-wood products like furniture, as well as mulch, compost, and other products.
Metals—including steel, copper, and brass—are also valuable commodities to recycle.
Additionally, although cardboard packaging from home-building sites is not classified as a C&D
material, it does make its way into the mixed C&D stream, and many markets exist for recycling
this material.
Re buying C&D Waste: Buying used C&D materials and recycled content products for use in
new construction can:
• Boost the local economy as recovered materials are typically locally sourced.
• Lower construction and renovation costs while maintaining building function and
performance.
• Ensure materials collected from reuse and recycling programs will be used again in the
manufacture of new products and/or new construction, thereby fully realizing the benefits
of reuse and recycling efforts;
• Preserve local architectural character and historic significance (in cases of preserved or
restored buildings).
Prof. U.T. Kulkarni

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