Solid Waste

Solid wastes are the wastes arising from human activities and are normally solid as opposed to liquid or gaseous and are discarded as useless or unwanted. Focused on urban waste (MSW) as opposed to agricultural, mining and industrial wastes.

•Integrated Solid Waste Management (ISWM) is the term applied to all the activities associated with the management of society's wastes.

•In medieval times, wastes discarded in the streets led to the breeding of rats and the associated fleas which carried the bubonic plague. The lack of management of solid wastes thus led to the Black Plague which killed half of 14th century Europe.

•USPHS has traced 22 human diseases to improper solid waste management.

•Solid wastes also have a great potential to pollute the air and water. Mining tailings from gold and silver mines will probably being spilling arsenic into the water supply forever.

•Materials Flow - The best way to reduce solid wastes is not to create them in the first place. Others methods include: decrease consumption of raw material and increase the rate of recovery of waste materials.

•Technological advances - Increased use of plastics and fast, pre-prepared foods

Solid Waste Management

Solid waste management is the control of :

-generation, materials are identified as being no longer value

-storage, management of wastes until they are put into a container

-collection, gathering of solid wastes and recyclable materials and the transport of these materials where the collection vehicle is emptied. 50% or higher of the total cost.

-processing, source separated (at the home) vs. commingled (everything together) is a big issue. Includes: physical processes such as shredding and screening, removal of bulky material, and chemical and biological processes such as incineration and composting.

-transfer and transport, small trucks to the biggest trucks allowable

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- disposal of solid waste, landfilling with or without attempting to recover resources in a manner that is in accord with:

- public health- economics- engineering- conservation- aesthetics-public attitudes

Final disposal at the turn of the century included:- dumping on land- dumping in water- plowing into soil- feeding to hogs- incineration

Modern landfilling was begun in the 1940's

Intergrated Solid Waste Management

Hierarchy - adopted by EPA to rank actions:

-source reduction, most useful, may involve design of packaging with minimum toxic content, minimum volume or a longer useful life.

-Recycling

-waste combustion (transformation), physical, chemical and biological alteration of the waste for the purposes of:

- improving efficiency- recover reusable material, glass- recover conversion products, compost

- landfilling, material that:- cannot be recycles- has no further use- residual matter attendant to another process, ash left over

after combustion

Landfill Classification

Classification Waste

I Hazardous Waste

II Designated Waste

III MSW

Factor that Effect Generation Rates

•Source Reduction and Recycling. Design with disposal in mind.

•Public Attitudes and Legislation. If not reimbursed, the public must be recruited to a "tree saving" mentality. Legislation includes bottle laws, AB939, green waste pick-ups.

•Geographic and Physical Factors. The bigger the yard and the longer the growing season, the more the waste. Seasonal, fall leaves, Christmas gifts, spring cleanup. Kitchen grinders contribute a minimal reduction.

•Frequency. More waste is collected if the frequency is increased. Note that more wastes are not generated.

Handling

A. Low Rise

Single family detached and attached Single family detached

- separate recyclables at the MRF, not at the home- variety of storage containers and mixed waste: plastic bags, 32

gallon galvanized or plastic, cardboard boxes-90 gallons containers equipped with wheels, mixed waste

B. Low and Medium Rise

Basement storage by residents and moving of the container by maintenance personnel.

Large outdoor containers, located in special areas that are emptied mechanically by the collection truck

C. High Rise Apartments

Porters pick up the waste at the apartment door.

Wastes are taken to the SW area by tenants

Chutes on each floor (12-36")

1-2lbs/tenant.day

Vacuum transport systems have been used most notably at Disney World.

D. Commercial and Industrial Facilities

Commercial - removed from work area by wheeled containers or blanket wrapped and transported via the service area to a disposal/processing area. Compaction would not be unusual.

Industrial area - May be more susceptible to the profit motive e.g. can order employees to recycle cans

Collection System

Collection System

Need for Transfer Operations

A. General

Used when:-Direct hauling to the processing center or disposal site is no long economically feasible.

- When the disposal site or processing center is in a remote location and cannot be reached directly by highway.

Integral part of MRFs.

Becoming popular AT landfills for individuals and other non-commercial haulers.

B. Excessive Haul Distances

Originally horse drawn smaller carts transferred their waste to larger vehicles.

The internal combustion engine and cheap fuel fostered direct haul to dumps.

Considering NIMBY and the economy of scale of larger sites, the current trend is to mega-facilities in remote locations once again necessitating transfer stations.

Decision between transfer and direct haul is usually an economic one.