wastewater

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/07/22 03:24:52」(JST)

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Greywater (a type of wastewater) in a settling tank

Wastewater, also written as waste water, is any water that has been adversely affected in quality by anthropogenic influence. Wastewater can originate from a combination of domestic, industrial, commercial or agricultural activities, surface runoff or stormwater, and from sewer inflow or infiltration.

Municipal wastewater (also called sewage) is usually conveyed in a combined sewer or sanitary sewer, and treated at a wastewater treatment plant. Treated wastewater is discharged into receiving water via an effluent pipe. Wastewaters generated in areas without access to centralized sewer systems rely on on-site wastewater systems. These typically comprise a septic tank, drain field, and optionally an on-site treatment unit. The management of wastewater belongs to the overarching term sanitation, just like the management of human excreta, solid waste and stormwater (drainage).

Sewage is a type of wastewater that comprises domestic wastewater and is therefore contaminated with feces or urine from people's toilets, but the term sewage is also used to mean any type of wastewater. Sewerage is the physical infrastructure, including pipes, pumps, screens, channels etc. used to convey sewage from its origin to the point of eventual treatment or disposal.

Sources

Wastewater can come from:

• Human excreta (feces and urine) often mixed with used toilet paper or wipes; this is known as blackwater if it is collected with flush toilets
• Washing water (personal, clothes, floors, dishes, cars, etc.), also known as greywater or sullage
• Surplus manufactured liquids from domestic sources (drinks, cooking oil, pesticides, lubricating oil, paint, cleaning liquids, etc.)
• Urban runoff from highways, roads, carparks, roofs, sidewalks/pavements (contains oils, animal feces, litter, gasoline/petrol, diesel or rubber residues from tires, soapscum, metals from vehicle exhausts, de-icing agents, etc.)
• Storm drains (may include trash)
• Manmade liquids (illegal disposal of pesticides, used oils, etc.)
• Industrial waste
• Industrial site drainage (silt, sand, alkali, oil, chemical residues);
  • Industrial cooling waters (biocides, heat, slimes, silt)
  • Industrial process waters
  • Organic or biodegradable waste, including waste from abattoirs, creameries, and ice cream manufacture
  • Organic or non bio-degradable/difficult-to-treat waste (pharmaceutical or pesticide manufacturing)
  • Extreme pH waste (from acid/alkali manufacturing, metal plating)
  • Toxic waste (metal plating, cyanide production, pesticide manufacturing, etc.)
  • Solids and emulsions (paper manufacturing, foodstuffs, lubricating and hydraulic oil manufacturing, etc.)
  • Hydraulic fracturing
  • Produced water from oil & natural gas production
• Agricultural pollution, direct and diffuse

Wastewater can be diluted or mixed with other types of water in the form of:

• Seawater ingress (high volumes of salt and microbes)
• Direct ingress of river water
• Rainfall collected on roofs, yards, hard-standings, etc. (generally clean with traces of oils and fuel)
• Groundwater infiltrated into sewage

After it has undergone some treatment, the "treated wastewater" remains, e.g.:

• Septic tank discharge
• Sewage treatment plant discharge

Pollutants

The composition of wastewater varies widely. This is a partial list of pollutants that may be contained in wastewater:

Chemical or physical pollutants

• Heavy metals, including mercury, lead, and chromium
• Organic particles such as feces, hairs, food, vomit, paper fibers, plant material, humus, etc.;
• Soluble organic material such as urea, fruit sugars, soluble proteins, drugs, pharmaceuticals, etc.;
• Inorganic particles such as sand, grit, metal particles, ceramics, etc.;
• Soluble inorganic material such as ammonia, road-salt, sea-salt, cyanide, hydrogen sulfide, thiocyanates, thiosulfates, etc.;
• Macro-solids such as sanitary napkins, nappies/diapers, condoms, needles, children's toys, dead animals or plants, etc.;
• Gases such as hydrogen sulfide, carbon dioxide, methane, etc.;
• Emulsions such as paints, adhesives, mayonnaise, hair colorants, emulsified oils, etc.;
• Toxins such as pesticides, poisons, herbicides, etc.
• Pharmaceuticals and hormones and other hazardous substances
• Thermal pollution from power stations and industrial manufacturers

Biological pollutants

If the wastewater contains human feces, as is the case for sewage, then it may also contain pathogens of one of the four types:

• Bacteria (for example Salmonella, Shigella, Campylobacter, Vibrio cholera),
• Viruses (for example hepatitis A, rotavirus, enteroviruses),
• Protozoa (for example Entamoeba histolytica, Giardia lamblia, Cryptosporidium parvum) and
• Parasites such as helminths and their eggs (e.g. ascaris (roundworm), ancylostoma (hookworm), trichuris (whipworm));

It can also contain non-pathogenic bacteria and animals such as insects, arthropods, small fish.

Quality indicators

Main article: Wastewater quality indicators

Any oxidizable material present in an aerobic natural waterway or in an industrial wastewater will be oxidized both by biochemical (bacterial) or chemical processes. The result is that the oxygen content of the water will be decreased.

Since all natural waterways contain bacteria and nutrients, almost any waste compounds introduced into such waterways will initiate biochemical reactions (such as shown above). Those biochemical reactions create what is measured in the laboratory as the biochemical oxygen demand (BOD). Such chemicals are also liable to be broken down using strong oxidizing agents and these chemical reactions create what is measured in the laboratory as the chemical oxygen demand (COD). Both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been widely adopted as a measure of pollution effect. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants.

Treatment

Main article: Wastewater treatment

At a global level, around 80% of wastewater produced is dischared into the environment untreated, causing widespread water pollution.

There are numerous processes that can be used to clean up wastewaters depending on the type and extent of contamination. Wastewater can be treated in wastewater treatment plants which include physical, chemical and biological treatment processes. Municipal wastewater is treated in sewage treatment plants (which may also be referred to as wastewater treatment plants). Agricultural wastewater may be treated in agricultural wastewater treatment processes, whereas industrial wastewater is treated in industrial wastewater treatment processes.

For municipal wastewater the use of septic tanks and other On-Site Sewage Facilities (OSSF) is widespread in some rural areas, for example serving up to 20 percent of the homes in the U.S.

One type of aerobic treatment system is the activated sludge process, based on the maintenance and recirculation of a complex biomass composed of micro-organisms able to absorb and adsorb the organic matter carried in the wastewater. Anaerobic wastewater treatment processes (UASB, EGSB) are also widely applied in the treatment of industrial wastewaters and biological sludge. Some wastewater may be highly treated and reused as reclaimed water. Constructed wetlands are also being used.

Disposal

Industrial wastewater effluent with neutralized pH from tailing runoff in Peru.

In some urban areas, municipal wastewater is carried separately in sanitary sewers and runoff from streets is carried in storm drains. Access to either of these is typically through a manhole. During high precipitation periods a combined sewer overflow can occur, forcing untreated sewage to flow back into the environment. This can pose a serious threat to public health and the surrounding environment.

Sewage may drain directly into major watersheds with minimal or no treatment but this usually has serious impacts on the quality of an environment and on the health of people. Pathogens can cause a variety of illnesses. Some chemicals pose risks even at very low concentrations and can remain a threat for long periods of time because of bioaccumulation in animal or human tissue.

Wastewater may be pumped underground through an injection well.

Reuse

Main article: Reclaimed water

Treated wastewater can be reused in industry (for example in cooling towers), in artificial recharge of aquifers, in agriculture and in the rehabilitation of natural ecosystems (for example in wetlands). In rarer cases it is also used to augment drinking water supplies. There are several technologies used to treat wastewater for reuse. A combination of these technologies can meet strict treatment standards and make sure that the processed water is hygienically safe, meaning free from bacteria and viruses. The following are some of the typical technologies: Ozonation, ultrafiltration, aerobic treatment (membrane bioreactor), forward osmosis, reverse osmosis, advanced oxidation.

Some water demanding activities do not require high grade water. In this case, wastewater can be reused with little or no treatment. One example of this scenario is in the domestic environment where toilets can be flushed using greywater from baths and showers with little or no treatment.

Irrigation with recycled wastewater can also serve to fertilize plants if it contains nutrients, such as nitrogen, phosphorus and potassium. In developing countries, agriculture is using untreated wastewater for irrigation - often in an unsafe manner. There can be significant health hazards related to using untreated wastewater in agriculture. The World Health Organization developed guidelines for safe use of wastewater in 2006.

Legislation

Further information: Reclaimed water § Guidelines and regulations

United States

The Clean Water Act is the primary federal law in the United States governing water pollution.

Philippines

In the Philippines, Republic Act 9275, otherwise known as the Philippine Clean Water Act of 2004, is the governing law on wastewater management. It states that it is the country's policy to protect, preserve and revive the quality of its fresh, brackish and marine waters, for which wastewater management plays a particular role.

Nigeria

In the Nigeria, the Water Resources Act of 1993 is the law responsible for all kinds of water management.

See also

• List of waste-water treatment technologies
• Sanitation
• Waste management
• Water management
• Water pollution

English Journal

• Starch-based bio-elastomers functionalized with red beetroot natural antioxidant.

• Tran TN1, Athanassiou A2, Basit A3, Bayer IS4.
• Food chemistry.Food Chem.2017 Feb 1;216:324-33. doi: 10.1016/j.foodchem.2016.08.055. Epub 2016 Aug 20.
• Red beetroot (RB) powder was incorporated into starch-based bio-elastomers to obtain flexible biocomposites with tunable antioxidant properties. Starch granules within the bio-elastomers affected the release of the antioxidant molecule betanin in the RB powder. The bio-elastomers were hydrophobic an
• PMID 27596427

• A food waste utilization study for removing lead(II) from drinks.

• Kaplan Ince O1, Ince M2, Yonten V3, Goksu A2.
• Food chemistry.Food Chem.2017 Jan 1;214:637-43. doi: 10.1016/j.foodchem.2016.07.117. Epub 2016 Jul 21.
• This is the first study about removal of lead (Pb(II)) from energy drinks. In this paper, food waste, namely eggshell (hydroxyapatite) utilization, was used to remove Pb(II) from mineral water and energy drinks. Mineral water and energy drinks were chosen for removal of lead since the latter is seve
• PMID 27507520

• Size-specific imprinted polymer embedded carbon nanodots modified magnetic nanoparticle for specific recognition of titanium nanoparticle: The round versus round.

• Patra S1, Choudhary R1, Roy E1, Madhuri R2, Sharma PK3.
• Biosensors & bioelectronics.Biosens Bioelectron.2016 Dec 15;86:818-26. doi: 10.1016/j.bios.2016.07.084. Epub 2016 Jul 26.
• Like the two sides of a coin, any new invention or discovery also possess their two faces. Similarly, while nanomaterials were identified as a boon in several fields like industrial, medicinal or agriculture; some of them have been also validated as a risk to the environment and living organisms. In
• PMID 27487305

Japanese Journal

• Extracellular oxidases of Cerrena sp. complementarily functioning in artificial dye decolorization including laccase, manganese peroxidase, and novel versatile peroxidases

• Hibi Makoto,Hatahira Satoko,Nakatani Masato,Yokozeki Kenzo,Shimizu Sakayu,Ogawa Jun
• Biocatalysis and Agricultural Biotechnology 1(3), 220-225, 2012-07
• … Optimized VPI/mediator-coupling decolorizing will be widely used for industrial wastewater treatment. …
• NAID 120004247249

• Effect of carbon source and COD/NON ratio on anaerobic simultaneous denitrification and methanogenesis for high-strength wastewater treatment

• Xie Li,Chen Jinrong,Wang Rui [他]
• Journal of bioscience and bioengineering 113(6), 759764, 2012-06
• NAID 40019318951

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