Sludge Drying Beds

Sludge drying bed is used as the last step of dewatering system. The sludge of the system is dewatered on these beds by evaporation and drainage. Moreover, the cationic polymer can be added to get faster and easier dewatering process. The polymer accelerates the particle agglomeration, increasing the total amount of water that can be drained and reducing the amount of water that needs to be evaporated.

Close sand sludge drying bed is used in this dewatering process. This type of beds includes gravel, sand and sludge layers. Also, at the bottom part, under the gravel layer, there are plastic pipes for the under drainage. Closed sand drying bed is chosen do to EPA.

Baltimore RESCO Trash-to-Energy Plant

Baltimore RESCO Solid waste plant is located in Baltimore, Maryland. It is one of the biggest solid waste plant in United States. In this plant wastes are burned to energy supply.

There are 16 plants like this one in the U.S.   This plant was opened in the fall of 1984 and services the needs of the city of Baltimore, Baltimore County, and the surrounding county of Anne Arundel. It has processed more than 9 million tons of waste so far, and can provide electricity for as many as 40,000 homes.  The steam from the plant satisfies the heating needs of the city of Baltimore and a large portion of its cooling needs.

You can reach the detailed trip notes from the following link.

Baltimore RESCO Solid Waste Plant, technical trip : http://www.eia.doe.gov/kids/energy_fungames/energyant_trips/trip_resco.html

Refuse Type, Amount and Incinerator Discharge

The incinerator be capable of handling garbage and rubbish up to a size limited only by the dimensionas of hopper door; larger-size refuse to be directly to the basement incinerators.

Inflammable refuse such as paint and lacquer containers, aerosol cans not be placed in flue-fed incinerators.

For design purposes, 2 pounds of refuse per person per day be assumed, with a unit weight per cubic foot of app. 5 pounds and that refuse be considered to comprise, by weight, 80% rubbish and 20% garbage, with heat content of 6000 Btu per pound.

Incinerator discharge is done by followings;

1- Particulate matter such as fly ash.
2- Smoke and opaque materials such as unburned hydracarbons, and
3- Odors emanating from one or a combination of such incineration products.

What is Incinerator?

It is a developed type of waste burner used in homes. Development of performance requirement and evaluative procedures for apartment building incineratorsconsistent with reducing air pollution to a minimum. In addition adaptation of existing or development of new incinerator designs which will ensure meeting the performance requirements will be in all other incinerator ways suitable for use.

The functions of a home incinerator are to;
1- Offer a convenience to tenants
2- Provide a more sanitary method of refuse disposal than container storage collection.
3- Serve as a labor-saving device for building owners.
4- Serves as a labor and cost-saving device for the municipality in reducing the weight and bulk of meterial which must be hauled from apartment building to final disposition point.

Municipal Wastes

Landfill means waste disposal on land. The practice has had various titles over the years: tips (UK); sanitary landfill (USA); coups (Scotland); dumps (Worldwide). Its opponents have given it less attractive names.

Traditionally, waste meterials have been deposited in voids or on adjacent land of little or no commercial or agriceltural value. Lack of finance and expertise had led to considerable environmental problems; water pollution, air pollution and vermin.

Maximizing Waste Management Efficiency through the Use of RFID

Today we look at the research of Maximizing Waste Management Efficiency through the Use of RFID by Josh Wyatt from Texas Instruments.

Josh Wyatt is an RFID applications/systems engineer for the Texas Instruments RFID
Systems Group.

Increasing recycling and reducing disposal, while making the fee structures equitable, are the primary waste management operations poised to benefit from low frequency RFID technology.

As cities and corporations seek to improve their waste collection processes, RFID technology presents an opportunity to maximize waste management efficiency. With RFID, the process is automated, and has the potential to provide improved value for the waste management companies and the communities/citizens they serve. Additionally, the environmental impact is yet another incentive and positive byproduct of implementing change in the manual system.

In models that implement a PAYT system, individuals are more inclined to reduce, reuse or recycle if they are charged for the amount of waste they produce and are credited in some way for the amount of recyclable material they place out for collection. The hauler companies have an interest in better understanding the true cost structure of their businesses and how they can be more effective and thus, improve their processes. The RFID piece of the equation plays a pivotal
role in the waste management industry because it introduces a proven, rugged, low maintenance, unique identifier that the collection and billing processes can use to truly automate the system.

Texas Instruments, with its application experience in waste management, offers low frequency RFID solutions that automate and improve the entire waste collection process.

You can reach the full text from http://www.solidwastemag.com/PostedDocuments/PDFs/2008/TI%20Waste%20Management%20White%20Paper.pdf

Hierarchy of Solid Waste Management

Used to rank actions to implement programs within the community.

A. Source reduction
B. Recycling/reuse
C. Waste transfor.
D. landfilling

E.g. ISWM hierarchy adopted by the US EPA...

A. Source reduction can be achieved by design, manufacture and packaging of products also selective buying and reuse.

B. Recycling helps to reduce the demand on resources and decreases the amount to be landfilled. It involves

* Separation and collection of waste materials
* Preparation of these materials for reuse,reprocessing and remanufacture.

C. Waste transformation is supplied by altering the waste physically, chemically, and biologically (decreases the amount to be landfilled)

D. Landfilling is ultimately used for, SW that cannot be recycled and of no further
use,residual matter after SW separated in materials recovery facility (MRF), Residual matter after recovery of conversion products or energy.

Planning an integrated waste system for a given region should involve comparison of the environmental impacts and economic costs of different schemes to determine which are environmentally and economically sustainable in that region

INTEGRATED SOLID WASTE MANAGEMENT

When all of the functional elements have been evaluated for use and all interfaces and connections between elements matched for effectiveness and economy - community developed an ISWM system.

In dealing waste there are two fundamental requirements;
- Less waste
- Effective system for managing waste still produced

The costs of raw materials and energy, and rising disposal costs for commercial and industrial waste will ensure that waste reduction continues to be pursued by industry for
- Economic
- Environmental reasons

Designing an effective solid waste management system

Strive for both of the following;
- Environmental sustainability
- Economic sustainability

To achieve these, the system should be integrated; a system that deals with
- All types of solid waste materials
- All sources of solid waste (domestic, industrial,...)
- After waste collection and sorting


Note that to handling all waste in an environmentally sustainable way requires a range of the treatment options.

Landfill is the only method that can handle all wastes alone but may posses environmental problems.

Using other options before landfilling can reduce or eliminate some waste streams, reduce volume, improve physical and chemical stability of the residue space requirements decreases and also environmental impacts decreases.

Sources, Types and Composition of SW

SWs can be seperated into 4 main category as follows;

1- Municipal Solid Wastes
2- Industrial Solid Wastes
3- Agricultural Solid Wastes
4- Treatment Plant sites, incinerators

Solid Waste Management Activities

The activities associated with the management of Solid Waste can be grouped into six fuctional groups;

1- Waste Generation.
This step is simply identification step.

2- Waste handling and seperation, storage, and processing at the source.
Handling and separation activities until placed in storage containers. From the stand point of materials specifications and revenues from the sale of recovered metarials, best place to seperate for reuse and recyling.

3- Collection
Gathering of the solid waste and recyclables.

4- Seperation and processing and transformation of solid wastes.
Seperation and processing usually occurs at metarials recovery center (MRF), transfer station, combustion facilities, disposal sites.

5- Transfer and transport.

6- Disposal
Landfilling is the final fate of the all solids.

History of Solid Waste Disposal

* Lack of Solid Waste management led to the epidemic of plague that killed 50 percent of 14th century Europians.

* By 19th century, public health measures were started tı be taken collection and disposal of food wastes to control vectors of disease.

- In 500 BC, the Athens organized the first municipal landfill in the western world and required waste disposal tı be at least one mile from city walls.

- The first incinerator in the US is built on Governor's Island, New York (1885)

- In 1888, English Parliament puts a ban on waste disposal in public waterways and ditches. Waste disposal methods involve simply throwing garbage out of windows and doors.

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