Clean Water Act References to "BMP"

Clean Water Act References to "BMP"

Congress referred to BMP in several sections of the U.S. Clean Water Act (CWA) but did not define the term.

• The 1977 CWA used the term in describing the areawide waste treatment planning program^[1] and in procedures for controlling toxic pollutants associated with industrial discharges.^[2] The "Section 404" program, which covers dredge and fill permits, refers to BMPs in one of the enforcement exemptions.^[3]
• References to stormwater BMPs first appear in the 1987 amendment to the CWA in describing the Nonpoint Source Management Demonstration Program.^[4]
• Another stormwater BMP reference was added in 2001 with the authorization for a Wet Weather Watershed Pilot Project program.^[5]

Best Management Practise

Best Management Practices (BMP) is a term used in the United States to describe a type of water pollution control. Historically the term has referred to auxiliary pollution controls in the fields of industrial wastewater control and municipal sewage control, while in stormwater management (both urban and rural) and wetland management, BMPs may refer to a principal control or treatment technique as well.

Beginning in the twentieth century, designers of industrial and municipal sewage pollution controls typically utilized engineered systems (e.g. filters, clarifiers, biological reactors) to provide the central components of pollution control systems, and used the term "BMPs" to describe the supporting functions for these systems, such as operator training and equipment maintenance. Stormwater management, as a specialized area within the field of environmental engineering, emerged later in the 20th century, and practitioners have used the term BMP to describe both structural or engineered control devices and systems (e.g. retention ponds) to treat polluted stormwater, as well as operational or procedural practices (e.g. minimizing use of chemical fertilizers and pesticides).

Contents

[hide]

• 1 Clean Water Act References to "BMP"
• 2 EPA Definitions
• 3 Industrial Wastewater BMPs
• 4 Stormwater Management BMPs
• 5 See also
• 6 References
• 7 External links

Industrial Wastetreatment

Removal of biodegradable organics

Biodegradable organic material of plant or animal origin is usually possible to treat using extended conventional wastewater treatment processes such as activated sludge or trickling filter.^[1][2] Problems can arise if the wastewater is excessively diluted with washing water or is highly concentrated such as neat blood or milk. The presence of cleaning agents, disinfectants, pesticides, or antibiotics can have detrimental impacts on treatment processes.

[edit] Activated sludge process

Main article: Activated sludge

A generalized, schematic diagram of an activated sludge process.

Activated sludge is a biochemical process for treating sewage and industrial wastewater that uses air (or oxygen) and microorganisms to biologically oxidize organic pollutants, producing a waste sludge (or floc) containing the oxidized material. In general, an activated sludge process includes:

• An aeration tank where air (or oxygen) is injected and thoroughly mixed into the wastewater.
• A settling tank (usually referred to as a "clarifier" or "settler") to allow the waste sludge to settle. Part of the waste sludge is recycled to the aeration tank and the remaining waste sludge is removed for further treatment and ultimate disposal.

[edit] Trickling filter process

Main article: Trickling filter

Image 1: A schematic cross-section of the contact face of the bed media in a trickling filter

A typical complete trickling filter system

A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over which wastewater flows downward and contacts a layer (or film) of microbial slime covering the bed media. Aerobic conditions are maintained by forced air flowing through the bed or by natural convection of air. The process involves adsorption of organic compounds in the wastewater by the microbial slime layer, diffusion of air into the slime layer to provide the oxygen required for the biochemical oxidation of the organic compounds. The end products include carbon dioxide gas, water and other products of the oxidation. As the slime layer thickens, it becomes difficult for the air to penetrate the layer and an inner anaerobic layer is formed.

The components of a complete trickling filter system are: fundamental components:

• A bed of filter medium upon which a layer of microbial slime is promoted and developed.
• An enclosure or a container which houses the bed of filter medium.
• A system for distributing the flow of wastewater over the filter medium.
• A system for removing and disposing of any sludge from the treated effluent.

The treatment of sewage or other wastewater with trickling filters is among the oldest and most well characterized treatment technologies.

A trickling filter is also often called a trickle filter, trickling biofilter, biofilter, biological filter or biological trickling filter.

[edit] Treatment of other organics

Synthetic organic materials including solvents, paints, pharmaceuticals, pesticides, coking products and so forth can be very difficult to treat. Treatment methods are often specific to the material being treated. Methods include distillation, adsorption, vitrification, incineration, chemical immobilisation or landfill disposal. Some materials such as some detergents may be capable of biological degradation and in such cases, a modified form of wastewater treatment can be used.

[edit] Treatment of acids and alkalis

Acids and alkalis can usually be neutralised under controlled conditions. Neutralisation frequently produces a precipitate that will require treatment as a solid residue that may also be toxic. In some cases, gasses may be evolved requiring treatment for the gas stream. Some other forms of treatment are usually required following neutralisation.

Waste streams rich in hardness ions as from de-ionisation processes can readily loose the hardness ions in a buildup of precipitated calcium and magnesium salts. This precipitation process can cause severe furring of pipes and can, in extreme cases, cause the blockage of disposal pipes. A 1 metre diameter industrial marine discharge pipe serving a major chemicals complex was blocked by such salts in the 1970s. Treatment is by concentration of de-ionisation waste waters and disposal to landfill or by careful pH management of the released wastewater.

[edit] Treatment of toxic materials

Toxic materials including many organic materials, metals (such as zinc, silver, cadmium, thallium etc.) acids, alkalis, non-metallic elements (such as arsenic or selenium) are generally resistant to biological processes unless very dilute. Metals can often be precipitated out by changing the pH or by treatment with other chemicals. Many, however, are resistant to treatment or mitigation and may require concentration followed by landfilling or recycling.

Industrial wastewater treatment

Industrial wastewater treatment covers the mechanisms and processes used to treat waters that have been contaminated in some way by man's industrial or commercial activities prior to its release into the environment or its re-use.
Most industries produce some wet waste although recent trends in the developed world have been to minimise such production or recycle such waste within the production process. However, many industries remain dependent on processes that produce wastewaters.

Contents [hide] 1 Sources of industrial wastewater 1.1 Agricultural waste 1.2 Iron and steel industry 1.3 Mines and quarries 1.4 Food industry 1.5 Complex organic chemicals industry 1.6 Nuclear industry 1.7 Water treatment 2 Treatment of industrial wastewater 2.1 Solids removal 2.2 Oils and grease removal 2.3 Removal of biodegradable organics 2.3.1 Activated sludge process 2.3.2 Trickling filter process 2.4 Treatment of other organics 2.5 Treatment of acids and alkalis 2.6 Treatment of toxic materials 3 See also 4 References 5 External links

[edit] Sources of industrial wastewater

[edit] Agricultural waste

See Agricultural wastewater treatment

[edit] Iron and steel industry

The production of iron from its ores involves powerful reduction reactions in blast furnaces. Cooling waters are inevitably contaminated with products especially ammonia and cyanide. Production of coke from coal in coking plants also requires water cooling and the use of water in by-products separation. Contamination of waste streams includes gasification products such as benzene, naphthalene, anthracene, cyanide, ammonia, phenols , cresols together with a range of more complex organic compounds known collectively as polycyclic aromatic hydrocarbons (PAH).
The conversion of iron or steel into sheet, wire or rods requires hot and cold mechanical transformation stages frequently employing water as a lubricant and coolant. Contaminants include hydraulic oils, tallow and particulate solids. Final treatment of iron and steel products before onward sale into manufacturing includes pickling in strong mineral acid to remove rust and prepare the surface for tin or chromium plating or for other surface treatments such as galvanisation or painting. The two acids commonly used are hydrochloric acid and sulphuric acid. Wastewaters include acidic rinse waters together with waste acid. Although many plants operate acid recovery plants, (particularly those using Hydrochloric acid), where the mineral acid is boiled away from the iron salts, there remains a large volume of highly acid ferrous sulphate or ferrous chloride to be disposed of. Many steel industry wastewaters are contaminated by hydraulic oil also known as soluble oil

Types of aerated lagoons or basins

There are many methods for aerating a lagoon or basin:

• Motor-driven floating surface aerators
• Motor-driven submerged aerators
• Motor-driven fixed-in-place surface aerators
• Injection of compressed air through submerged diffusers

[edit] Floating surface aerators

A Typical Surface-Aerated Basing (using motor-driven floating aerators)

Ponds or basins using floating surface aerators achieve 80 to 90% removal of BOD with retention times of 1 to 10 days.^[4] The ponds or basins may range in depth from 1.5 to 5.0 metres.^[4]
In a surface-aerated system, the aerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and and for contacting the reactants (that is, oxygen, wastewater and microbes). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7 kg O₂/kWh. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units.^[4]

"Retarding Basin" dan Banjir Jakarta

"Retarding Basin" dan Banjir Jakarta oleh Dr.-Ing. Ir. Agus Maryono


Jakarta diterjang banjir bandang lagi. Kali ini lebih luas dan menyedihkan, setelah banjir besar 2002 dan banjir kecil dan menengah tahun 2003, 2004, 2005, dan 2006.

Adakah metode efektif yang ramah lingkungan untuk mengatasi banjir sekaligus bisa dimanfaatkan untuk mengatasi kekeringan kota?

Oleh banyak negara, masalah serupa diselesaikan dengan metode retarding basin ramah lingkungan. Filosofi metode ini adalah mencegat air yang mengalir dari hulu dengan membuat kolam-kolam retensi (retarding basin) sebelum masuk ke hilir. Retarding basin dibuat di bagian tengah dan hulu kanan-kiri alur sungai-sungai yang masuk kawasan yang akan diselamatkan.