Computer recycling

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Computer_recycling 

 

Computer monitors are typically packed into low stacks on wooden pallets for recycling and then shrink-wrapped.

Computer recycling, electronic recycling or e-waste recycling is the disassembly and separation of components and raw materials of waste electronics. Although the procedures of re-use, donation and repair are not strictly recycling, these are other common sustainable ways to dispose of IT waste.

In 2009, 38% of computers and a quarter of total electronic waste was recycled in the United States, 5% and 3% up from 3 years prior respectively. Since its inception in the early 1990s, more and more devices are recycled worldwide due to increased awareness and investment. Electronic recycling occurs primarily in order to recover valuable rare earth metals and precious metals, which are in short supply, as well as plastics and metals. These are resold or used in new devices after purification, in effect creating a circular economy. Such processes involve specialised facilities and premises, but within the home or ordinary workplace, sound components of damaged or obsolete computers can often be reused, reducing replacement costs.

Recycling is considered environmentally friendly because it prevents hazardous waste, including heavy metals and carcinogens, from entering the atmosphere, landfill or waterways. While electronics consist a small fraction of total waste generated, they are far more dangerous. There is stringent legislation designed to enforce and encourage the sustainable disposal of appliances, the most notable being the Waste Electrical and Electronic Equipment Directive of the European Union and the United States National Computer Recycling Act.

Reasons for recycling

Obsolete computers and old electronics are valuable sources for secondary raw materials if recycled; otherwise, these devices are a source of toxins and carcinogens. Rapid technology change, low initial cost, and planned obsolescence have resulted in a fast-growing surplus of computers and other electronic components around the globe. Technical solutions are available, but in most cases a legal framework, collection system, logistics, and other services need to be implemented before applying a technical solution. The U.S. Environmental Protection Agency, estimates 30 to 40 million surplus PCs, classified as "hazardous household waste", would be ready for end-of-life management in the next few years. The U.S. National Safety Council estimates that 75% of all personal computers ever sold are now surplus electronics.

In 2007, the United States Environmental Protection Agency (EPA) stated that more than 63 million computers in the U.S. were traded in for replacements or discarded. Today, 15% of electronic devices and equipment are recycled in the United States. Most electronic waste is sent to landfills or incinerated, which releases materials such as lead, mercury, or cadmium into the soil, groundwater, and atmosphere, thus having a negative impact on the environment.

Many materials used in computer hardware can be recovered by recycling for use in future production. Reuse of tin, silicon, iron, aluminium, and a variety of plastics that are present in bulk in computers or other electronics can reduce the costs of constructing new systems. Components frequently contain copper, gold, tantalum, silver, platinum, palladium, and lead as well as other valuable materials suitable for reclamation.

Computer components contain many toxic substances, like dioxins, polychlorinated biphenyls (PCBs), cadmium, chromium, radioactive isotopes and mercury. A typical computer monitor may contain more than 6% lead by weight, much of which is in the lead glass of the cathode ray tube (CRT). A typical 15 inch (38 cm) computer monitor may contain 1.5 pounds (1 kg) of lead but other monitors have been estimated to have up to 8 pounds (4 kg) of lead. Circuit boards contain considerable quantities of lead-tin solders that are more likely to leach into groundwater or create air pollution due to incineration. In US landfills, about 40% of the lead content levels are from e-waste. The processing (e.g. incineration and acid treatments) required to reclaim these precious substances may release, generate, or synthesize toxic byproducts.

Export of waste to countries with lower environmental standards is a major concern. The Basel Convention includes hazardous wastes such as, but not limited to, CRT screens as an item that may not be exported transcontinentally without prior consent of both the country exporting and receiving the waste. Companies may find it cost-effective in the short term to sell outdated computers to less developed countries with lax regulations. It is commonly believed that a majority of surplus laptops are routed to developing nations. The high value of working and reusable laptops, computers, and components (e.g. RAM) can help pay the cost of transportation for many worthless commodities. Laws governing the exportation of waste electronics are put in place to govern recycling companies in developed countries which ship waste to Third World countries. However, concerns about the impact of e-recycling on human health, the health of recycling workers and environmental degradation remain. For example, due to the lack of strict regulations in developing countries, sometimes workers smash old products, propelling toxins on to the ground, contaminating the soil and putting those who do not wear shoes in danger. Other procedures include burning away wire insulation and acid baths to resell circuit boards. These methods pose environmental and health hazards, as toxins are released into the air and acid bath residue can enter the water supply.

Regulations

An abandoned Taxan monitor.

Europe

In Switzerland, the first electronic waste recycling system was implemented in 1991, beginning with collection of old refrigerators; over the years, all other electric and electronic devices were gradually added to the system. The established producer responsibility organization is SWICO, mainly handling information, communication, and organization technology. The European Union implemented a similar system in February 2003, under the Waste Electrical and Electronic Equipment Directive (WEEE Directive, 2002/96/EC).

Pan-European adoption of the Legislation was slow on take-up, with Italy and the United Kingdom being the final member states to pass it into law. The success of the WEEE directive has varied significantly from state to state, with collection rates varying between 13 kilograms per capita per annum to as little as 1 kg per capita per annum. Computers & electronic wastes collected from households within Europe are treated under the WEEE directive via Producer Compliance Schemes (whereby manufacturers of Electronics pay into a scheme that funds its recovery from household waste recycling centres (HWRCs)) and nominated Waste Treatment Facilities (known as Obligated WEEE).

However, recycling of ex corporate Computer Hardware and associated electronic equipment falls outside the Producer Compliance Scheme (Known as non-obligated). In the UK, Waste or obsolete corporate related computer hardware is treated via third party Authorized Treatment Facilities, who normally impose a charge for its collection and treatment.

Since mid 2020 the classification of WEEE changed with regards to POPs (persistent organic pollutants). In the UK WEEE containing POPs is now classified as a hazardous waste, these includes - Printed Circuit Boards, Cable from WEEE and Categories 1,2,3,6,7 (Cat 4 and 5 unless evidence provided to the contrary).

United States

Federal

The United States Congress considers a number of electronic waste bills, like the National Computer Recycling Act introduced by Congressman Mike Thompson (D-CA). The main federal law governing solid waste is the Resource Conservation and Recovery Act of 1976. It covers only CRTs, though state regulations may differ. There are also separate laws concerning battery disposal. On March 25, 2009, the House Science and Technology Committee approved funding for research on reducing electronic waste and mitigating environmental impact, regarded by sponsor Ralph Hall (R-TX) as the first federal bill to directly address electronic waste.

State

Many states have introduced legislation concerning recycling and reuse of computers or computer parts or other electronics. Most American computer recycling legislations address it from within the larger electronic waste issue.

In 2001, Arkansas enacted the Arkansas Computer and Electronic Solid Waste Management Act, which requires that state agencies manage and sell surplus computer equipment, establishes a computer and electronics recycling fund, and authorizes the Department of Environmental Quality to regulate and/or ban the disposal of computer and electronic equipment in Arkansas landfills.

The recently passed Electronic Device Recycling Research and Development Act distributes grants to universities, government labs and private industries for research in developing projects in line with e-waste recycling and refurbishment.

Asia

In Japan, sellers and manufacturers of certain electronics (such as televisions and air conditioners) are required to recycle them. This is covered by at least two legislations: the Law for the Promotion of Effective Utilization of Resources (LPUR); and, the Law for the Recycling of Specified Kinds of Home Appliances (LRHA). The former, which was passed in 2001, encouraged manufacturers to voluntarily help recycle goods while the LRHA, which was adopted in 2009, required more recycling efforts by both consumers and manufacturers of home appliances. However, no legislation exists to cover the recycling of computer or cellphone-related wastes.

It is required in South Korea and Taiwan that sellers and manufacturers of electronics be responsible for recycling 75% of their used products. In South Korea, some local governments have introduced recycling initiatives such as the case of Seoul, which launched its specialized e-waste recycling program. This includes the SR Center recycling facility, which takes apart and salvages materials from a fifth of the 10-ton e-waste that the city generates each year.

According to a report by UNEP titled, "Recycling – from E-Waste to Resources," the amount of e-waste being produced – including mobile phones and computers – could rise by as much as 500 percent over the next decade in some countries, such as India.

See also: Electronic waste by country

 

Electronic waste is often exported to developing countries.

 

4.5-volt, D, C, AA, AAA, AAAA, A23, 9-volt, CR2032 and LR44 cells are all recyclable in most countries.

One theory is that increased regulation of electronic waste and concern over the environmental harm in mature economies creates an economic disincentive to remove residues prior to export. Critics of trade in used electronics maintain that it is too easy for brokers calling themselves recyclers to export unscreened electronic waste to developing countries, such as China, India and parts of Africa, thus avoiding the expense of removing items like bad cathode ray tubes (the processing of which is expensive and difficult). The developing countries are becoming big dump yards of e-waste. Proponents of international trade point to the success of fair trade programs in other industries, where cooperation has led creation of sustainable jobs, and can bring affordable technology in countries where repair and reuse rates are higher.

Organizations like A2Z Group have stepped in to own up the responsibility to collect and recycle e-waste at various locations in India.

South Africa

Thanks to the National Environmental Management Act 1998 and National Environmental Management Waste Act 2008, any person in any position causing harm to the environment and failing to comply with the Waste Act could be fined R10 Million or put into jail or receive both penalties for their transgressions.

Recycling methods

Computers being collected for recycling at a pickup event in Olympia, Washington, United States.

Consumer recycling

Consumer recycling options consists of (see below) sale, donating computers directly to organizations in need, sending devices directly back to their original manufacturers, or getting components to a convenient recycler or refurbisher.

Scrapping recycling

In the recycling process, TVs, monitors, mobile phones and computers are typically tested for reuse and repaired. If broken, they may be disassembled for parts still having high value if labour is cheap enough. Other e-waste is shredded to roughly 100 mm pieces and manually checked to separate out toxic batteries and capacitors which contain poisonous metals. The remaining pieces are further shredded to ~10 mm and passed under a magnet to remove ferrous metals. An eddy current ejects non-ferrous metals, which are sorted by density either by a centrifuge or vibrating plates. Precious metals can be dissolved in acid, sorted, and smelted into ingots. The remaining glass and plastic fractions are separated by density and sold to re-processors. TVs and monitors must be manually disassembled to remove either toxic lead in CRTs or the mercury in flat screens.

Corporations face risks both for incompletely destroyed data and for improperly disposed computers. In the UK, some recycling companies use a specialized WEEE-registered contractor to dispose IT equipment and electrical appliances, who disposes it safely and legally. In America, companies are liable for compliance with regulations even if the recycling process is outsourced under the Resource Conservation and Recovery Act. Companies can mitigate these risks by requiring waivers of liability, audit trails, certificates of data destruction, signed confidentiality agreements, and random audits of information security. The National Association of Information Destruction is an international trade association for data destruction providers.

Sale

Online auctions are an alternative for consumers willing to resell for cash less fees, in a complicated, self-managed, competitive environment where paid listings might not sell. Online classified ads can be similarly risky due to forgery scams and uncertainty.

Take back

When researching computer companies before a computer purchase, consumers can find out if they offer recycling services. Most major computer manufacturers offer some form of recycling. At the user's request they may mail in their old computers, or arrange for pickup from the manufacturer.

Hewlett-Packard also offers free recycling, but only one of its "national" recycling programs is available nationally, rather than in one or two specific states. Hewlett-Packard also offers to pick up any computer product of any brand for a fee, and to offer a coupon against the purchase of future computers or components; it was the largest computer recycler in America in 2003, and it has recycled over 750,000,000 pounds (340,000,000 kg) of electronic waste globally since 1995. It encourages the shared approach of collection points for consumers and recyclers to meet.

Exchange

Manufacturers often offer a free replacement service when purchasing a new PC. For example, Dell Computers and Apple Inc. may take back old products when one buys a new one. Both refurbish and resell their own computers with a one-year warranty.

Many companies purchase and recycle all brands of working and broken laptops and notebook computers from individuals and corporations. Building a market for recycling of desktop computers has proven more difficult than exchange programs for laptops, smartphones and other smaller electronics. A basic business model is to provide a seller an instant online quote based on laptop characteristics, then to send a shipping label and prepaid box to the seller, to erase, reformat, and process the laptop, and to pay rapidly by cheque. A majority of these companies are also generalized electronic waste recyclers as well; organizations that recycle computers exclusively include Cash For Laptops, a laptop refurbisher in Nevada that claims to be the first to buy laptops online, in 2001.

Donations/nonprofits

With the constant rising costs due to inflation, many families or schools do not have the sufficient funds available for computers to be utilized along with education standards. Families also impacted by disaster suffer as well due to the financial impact of the situation they have incurred. Many nonprofit organizations, such as InterConnection.org, can be found locally as well as around the web and give detailed descriptions as to what methods are used for dissemination and detailed instructions on how to donate. The impact can be seen locally and globally, affecting thousands of those in need. In Canada non profit organizations engaged in computer recycling, such as The Electronic Recycling Association Calgary, Edmonton, Vancouver, Winnipeg, Toronto, Montreal, Computers for Schools Canada wide, are very active in collecting and refurbishing computers and laptops to help the non profit and charitable sectors and schools.

Junkyard Computing

The term junkyard computing is a colloquial expression for using old or inferior hardware to fulfill computational tasks while handling reliability and availability on software level. It utilizes abstraction of computational resources via software, allowing hardware replacement at very low effort. Ease of replacement is hereby a corner point since hardware failures are expected at any time due to the condition of the underlying infrastructure. This paradigm became more widely used with the introduction of cluster orchestration software like Kubernetes or Apache Mesos, since large monolithic applications require reliability and availability on machine level whereas this kind of software is fault tolerant by design. Those orchestration tools also introduced fairly fast set-up processes allowing to use junkyard computing economically and even making this pattern applicable in the first place. Further use cases were introduced when continuous delivery was getting more widely accepted. Infrastructure to execute tests and static code analysis was needed which requires as much performance as possible while being extremely cost effective. From an economical and technological perspective, junkyard computing is only practicable for a small number of users or companies. It already requires a decent number of physical machines to compensate for hardware failures while maintaining the required reliability and availability. This implies a direct need for a matching underling infrastructure to house all the computers and servers. Scaling this paradigm is also quite limited due to the increasing importance of factors like power efficiency and maintenance efforts, making this kind of computing perfect for mid-sized applications.

History

Although consumer electronics such as the radio have been popular since the 1920s, recycling was almost unheard of until the early 1990s. At the end of the 1970s, the accelerating pace of domestic consumer electronics drastically shortened the lifespan of electronics such as TVs, VCRs and audio. New innovations appeared more quickly, making older equipment considered obsolete. Increased complexity and sophistication of manufacture made local repair more difficult. The retail market shifted gradually, but substantially, from a few high-value items that were cherished for years and repaired when necessary, to short-lived items that were rapidly replaced owing to wear or simply fashion, and discarded rather than repaired. This was particularly evident in computing, highlighted by Moore's Law. In 1988 two severe incidents highlighted the approaching e-waste crisis. The cargo barge Khian Sea, was loaded with more than 14,000 tons of toxic ash from Pennsylvania which had been refused acceptance in New Jersey and the Caribbean. After sailing for 16 months, all the waste was dumped as "topsoil fertiliser" in Haiti and in the Bay of Bengal by November 1988. In June 1988, a large illegal toxic waste dump which had been created by an Italian company was discovered. This led to the formation of the Basel Convention to stem the flow of poisonous substances from developed countries in 1989.

In 1991, the first electronic waste recycling system was implemented in Switzerland, beginning with collection of old refrigerators but gradually expanding to cover all devices. The organisation SWICO handles the programme, and is a partnership between IT retailers.

The first publication to report the recycling of computers and electronic waste was published on the front page of the New York Times on April 14, 1993 by columnist Steve Lohr. It detailed the work of Advanced Recovery Inc., a small recycler, in trying to safely dismantle computers, even if most waste was landfilled. Several other companies emerged in the early 1990s, chiefly in Europe, where national 'take back' laws compelled retailers to use them.

After these schemes were set up, many countries did not have the capacity to deal with the sheer quantity of e-waste they generated or its hazardous nature. They began to export the problem to developing countries without enforced environmental legislation. This is cheaper: the cost of recycling of computer monitors in the US is ten times more than in China. Demand in Asia for electronic waste began to grow when scrap yards found they could extract valuable substances such as copper, iron, silicon, nickel and gold, during the recycling process.

The Waste Electrical and Electronic Equipment Directive (WEEE Directive) became European Law in February 2003 and covers all aspects of recycling all types of appliance. This was followed by Electronic Waste Recycling Act, enshrined in Californian law in January 2005.

The 2000s saw a large increase in both the sale of electronic devices and their growth as a waste stream: in 2002 e-waste grew faster than any other type of waste in the EU. This caused investment in modern, automated facilities to cope with the influx of redundant appliances.

E-cycling

E-cycling or "E-waste" is an initiative by the United States Environmental Protection Agency (EPA) which refers to donations, reuse, shredding and general collection of used electronics. Generically, the term refers to the process of collecting, brokering, disassembling, repairing and recycling the components or metals contained in used or discarded electronic equipment, otherwise known as electronic waste (e-waste). "E-cyclable" items include, but are not limited to: televisions, computers, microwave ovens, vacuum cleaners, telephones and cellular phones, stereos, and VCRs and DVDs just about anything that has a cord, light or takes some kind of battery.

Investment in e-cycling facilities has been increasing recently due to technology's rapid rate of obsolescence, concern over improper methods, and opportunities for manufacturers to influence the secondary market (used and reused products). Higher metal prices can result in more recycling taking place. The controversy around methods stems from a lack of agreement over preferred outcomes.

World markets with lower disposable incomes, consider 75% repair and reuse to be valuable enough to justify 25% disposal. Debate and certification standards may be leading to better definitions, though civil law contracts, governing the expected process are still vital to any contracted process, as poorly defined as "e-cycling".

Pros of e-cycling

The e-waste disposal occurring after processing for reuse, repair of equipment, and recovery of metals may be unethical or illegal when e-scrap of many kinds is transported overseas to developing countries for such processing. It is transported as if to be repaired and/or recycled, but after processing the less valuable e-scrap becomes e-waste/pollution there. Another point of view is that the net environmental cost must be compared to and include the mining, refining and extraction with its waste and pollution cost of new products manufactured to replace secondary products which are routinely destroyed in wealthier nations, and which cannot economically be repaired in older or obsolete products.

As an example of negative impacts of e-waste, pollution of groundwater has become so serious in areas surrounding China's landfills that water must be shipped in from 18 miles (29 km) away. However, mining of new metals can have even broader impacts on groundwater. Either thorough e-cycling processing, domestic processing or overseas repair, can help the environment by avoiding pollution. Such e-cycling can theoretically be a sustainable alternative to disposing of e-waste in landfills. In addition, e-cycling allows for the reclamation of potential conflict minerals, like gold and wolframite, which requires less of those to be mined and lessens the potential money flow to militias and other exploitative actors in third-world that profit from mining them.

Supporters of one form of "required e-cycling" legislation argue that e-cycling saves taxpayers money, as the financial responsibility would be shifted from the taxpayer to the manufacturers. Advocates of more simple legislation (such as landfill bans for e-waste) argue that involving manufacturers does not reduce the cost to consumers, if reuse value is lost, and the resulting costs are then passed on to consumers in new products, particularly affecting markets which can hardly afford new products. It is theorized that manufacturers who take part in e-cycling would be motivated to use fewer materials in the production process, create longer lasting products, and implement safer, more efficient recycling systems. This theory is sharply disputed and has never been demonstrated.

Criticisms of e-cycling

The critics of e-cycling are just as vocal as its advocates. According to the Reason Foundation, e-cycling only raises the product and waste management costs of e-waste for consumers and limits innovation on the part of high-tech companies. They also believe that e-cycling facilities could unintentionally cause great harm to the environment. Critics claim that e-waste doesn't occupy a significant portion of total waste.

Another opposition to e-cycling is that many problems are posed in disassembly: the process is costly and dangerous because of the heavy metals of which the electronic products are composed, and as little as 1–5% of the original cost of materials can be retrieved. A final problem that people find is that identity fraud is all too common in regards to the disposal of electronic products. As the programs are legislated, creating winners and losers among e-cyclers with different locations and processes, it may be difficult to distinguish between criticism of e-cycling as a practice, and criticism of the specific legislated means proposed to enhance it.

The fate of e-waste

Workers recovering metals from e-waste in Agbogbloshie, a e-waste recovery site in Ghana. Exported e-waste is frequently processed in situations that are unhealthy for the workers, where they are exposed to toxics.

A hefty criticism often lobbed at reuse based recyclers is that people think that they are recycling their electronic waste, when in reality it is actually being exported to developing countries like China, India, and Nigeria. For instance, at free recycling drives, "recyclers" may not be staying true to their word, but selling e-waste overseas or to parts brokers. Studies indicate that 50–80% of the 300,000 to 400,000 tons (270,000 to 360,000 tonnes) of e-waste is being sent overseas, and that approximately 2 million tons (1.8 million tonnes) per year go to U.S. landfills.

Although not possible in all circumstances, the best way to e-cycle is to upcycle e-waste. On the other hand, the electronic products in question are generally manufactured, and repaired under warranty, in the same nations, which anti-reuse recyclers depict as primitive. Reuse-based e-recyclers believe that fair-trade incentives for export markets will lead to better results than domestic shredding. There has been a continued debate between export-friendly e-cycling and increased regulation of that practice.

In the European Union, debate regarding the export of e-waste has resulted in a significant amendment to the WEEE directive (January 2012) with a view to significantly diminishing the export of WEEE (untreated e-waste). During debate in Strasburg, MEPs stated that "53 million tonnes of WEEE were generated in 2009 but only 18% collected for recycling" with the remainder being exported or sent to landfill. The Amendment, voted through by a unanimous 95% of representatives, removed the re-use (repair and refurbishmet) aspect of the directive and placed more emphasis upon recycling and recovery of precious metals and base metals. The changes went further by placing the burden upon registered exporters to prove that used equipment leaving Europe was "fit for purpose".

Policy issues and current efforts

Currently, pieces of government legislation and a number of grassroots efforts have contributed to the growth of e-cycling processes which emphasize decreased exports over increased reuse rates. The Electronic Waste Recycling Act was passed in California in 2003. It requires that consumers pay an extra fee for certain types of electronics, and the collected money be then redistributed to recycling companies that are qualified to properly recycle these products. It is the only state that legislates against e-waste through this kind of consumer fee; the other states' efforts focus on producer responsibility laws or waste disposal bans. No study has shown that per capita recovery is greater in one type of legislated program (e.g. California) versus ordinary waste disposal bans (e.g. Massachusetts), though recovery has greatly increased in states which use either method.

As of September, 2006, Dell developed the nation's first completely free recycling program, furthering the responsibilities that manufacturers are taking for e-cycling. Manufacturers and retailers such as Best Buy, Sony, and Samsung have also set up recycling programs. This program does not accept televisions, which are the most expensive used electronic item, and are unpopular in markets which must deal with televisions when the more valuable computers have been cherry picked.

Another step being taken is the recyclers’ pledge of true stewardship, sponsored by the Computer TakeBack Campaign. It has been signed by numerous recyclers promising to recycle responsibly. Grassroots efforts have also played a big part in this issue, as they and other community organizations are being formed to help responsibly recycle e-waste. Other grassroots campaigns are Basel, the Computer TakeBack Campaign (co-coordinated by the Grassroots Recycling Network), and the Silicon Valley Toxics Coalition. No study has shown any difference in recycling methods under the Pledge, and no data is available to demonstrate difference in management between "Pledge" and non-Pledge companies, though it is assumed that the risk of making false claims will prevent Pledge companies from wrongly describing their processes.

Many people believe that the U.S. should follow the European Union model in regards to its management of e-waste, such as the Extended Producer Responsibility, which was started in Sweden in 1990. In this program, a directive forces manufacturers to take responsibility for e-cycling; it also demands manufacturers' mandatory take-back and places bans on exporting e-waste to developing countries. British Columbia has more than 20 EPR programs under the Recycling Regulation legislation, which stops e-waste from being put into landfills and recycles them instead. There are more than 80 programs in Canada as of 2013.

Another longer-term solution is for computers to be composed of less dangerous products and many people disagree. No data has been provided to show that people who agree with the European model have based their agreement on measured outcomes or experience-based scientific method.

Data security

Electronic waste dump at Agbogbloshie, Ghana. Organized criminals commonly search the drives for information to use in local scams.

E-waste presents a potential security threat to individuals and exporting countries. Hard drives that are not properly erased before the computer is disposed of can be reopened, exposing sensitive information. Credit card numbers, private financial data, account information and records of online transactions can be accessed by most willing individuals. Organized criminals in Ghana commonly search the drives for information to use in local scams.

Government contracts have been discovered on hard drives found in Agbogbloshie, Ghana. Multimillion-dollar agreements from United States security institutions such as the Defense Intelligence Agency (DIA), the Transportation Security Administration and Homeland Security have all resurfaced in Agbogbloshie.

Reasons to destroy and recycle securely

There are ways to ensure that not only hardware is destroyed but also the private data on the hard drive. Having customer data stolen, lost, or misplaced contributes to the ever-growing number of people who are affected by identity theft, which can cause corporations to lose more than just money. The image of a company that holds secure data, such as banks, law firms, pharmaceuticals, and credit corporations is also at risk. If a company's public image is hurt, it could cause consumers to not use their services and could cost millions in business losses and positive public relation campaigns. The cost of data breaches "varies widely, ranging from $90 to $50,000 (under HIPAA's new HITECH amendment, that came about through the American Recovery and Revitalization act of 2009), as per customer record, depending on whether the breach is “low-profile” or “high-profile” and the company is in a non-regulated or highly regulated area, such as banking or medical institutions.”

There is also a major backlash from the consumer if there is a data breach in a company that is supposed to be trusted to protect their private information. If an organization has any consumer info on file, they must by law (Red Flags Clarification act of 2010) have written information protection policies and procedures in place, that serve to combat, mitigate, and detect vulnerable areas that could result in identity theft. The United States Department of Defense has published a standard to which recyclers and individuals may meet in order to satisfy HIPAA requirements.

Secure recycling

Countries have developed standards, aimed at businesses and with the purpose of ensuring the security of Data contained in 'confidential' computer media [NIST 800-88: US standard for Data Remanence][HMG CESG IS5, Baseline & Enhanced, UK Government Protocol for Data Destruction]. National Association for Information Destruction (NAID) "is the international trade association for companies providing information destruction services. Suppliers of products, equipment and services to destruction companies are also eligible for membership. NAID's mission is to promote the information destruction industry and the standards and ethics of its member companies." There are companies that follow the guidelines from NAID and also meet all Federal EPA and local DEP regulations.

The typical process for computer recycling aims to securely destroy hard drives while still recycling the byproduct. A typical process for effective computer recycling:

1. Receive hardware for destruction in locked and securely transported vehicles.
2. Shred hard drives.
3. Separate all aluminum from the waste metals with an electromagnet.
4. Collect and securely deliver the shredded remains to an aluminum recycling plant.
5. Mold the remaining hard drive parts into aluminum ingots.

The Asset Disposal and Information Security Alliance (ADISA) publishes an ADISA IT Asset Disposal Security Standard that covers all phases of the e-waste disposal process from collection to transportation, storage and sanitization's at the disposal facility. It also conducts periodic audits of disposal vendors.

Total organic carbon

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Total_organic_carbon 

 

2011 Ocean particulate organic carbon derived from the MODIS-aqua

Total organic carbon (TOC) is the amount of carbon found in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment. TOC may also refer to the amount of organic carbon in soil, or in a geological formation, particularly the source rock for a petroleum play; 2% is a rough minimum. For marine surface sediments average TOC content is 0.5% in the deep ocean, and 2% along the eastern margins.

A typical analysis for total carbon (TC) measures both the total organic carbon (TOC) present and the complementing total inorganic carbon (TIC), the latter representing the amount of non-organic carbon, like carbon in carbonate minerals. Subtracting the inorganic carbon from the total carbon yields TOC. Another common variant of TOC analysis involves removing the TIC portion first and then measuring the leftover carbon. This method involves purging an acidified sample with carbon-free air or nitrogen prior to measurement, and so is more accurately called non-purgeable organic carbon (NPOC).

Measurement

Carbon cycle

By regions

Carbon dioxide

Forms of carbon Total carbon (TC) Total organic carbon (TOC) Total inorganic carbon (TIC) Dissolved organic carbon (DOC) Dissolved inorganic carbon (DIC) Particulate organic carbon (POC) Particulate inorganic carbon (PIC) Primary production marine Black carbon Blue carbon Kerogen

Metabolic pathways

Carbon respiration

Carbon pumps

Carbon sequestration

Methane

Biogeochemical

Relationship of carbon-content categories

Since all TOC analyzers only actually measure total carbon, TOC analysis always requires some accounting for the inorganic carbon that is always present. One analysis technique involves a two-stage process commonly referred to as TC-IC. It measures the amount of inorganic carbon (IC) evolved from an acidified aliquot of a sample and also the amount of total carbon (TC) present in the sample. TOC is calculated by subtraction of the IC value from the TC of the sample. Another variant employs acidification of the sample to evolve carbon dioxide and measuring it as inorganic carbon (IC), then oxidizing and measuring the remaining non-purgeable organic carbon (NPOC). This is called TIC-NPOC analysis. A more common method directly measures TOC in the sample by again acidifying the sample to a pH value of two or less to release the IC gas but in this case to the air not for measurement. The remaining non-purgeable CO₂ gas (NPOC) contained in the liquid aliquot is then oxidized releasing the gases. These gases are then sent to the detector for measurement.

Whether the analysis of TOC is by TC-IC or NPOC methods, it may be broken into three main stages:

1. Acidification
2. Oxidation
3. Detection and Quantification

The first stage is acidification of the sample for the removal of the IC and POC gases. The release of these gases to the detector for measurement or to the air is dependent upon which type of analysis is of interest, the former for TC-IC and the latter for TOC (NPOC).

Acidification

Addition of acid and inert-gas sparging allows all bicarbonate and carbonate ions to be converted to carbon dioxide, and this IC product vented along with any purgeable organic carbon (POC) that was present.

Oxidation

The second stage is the oxidation of the carbon in the remaining sample in the form of carbon dioxide (CO₂) and other gases. Modern TOC analyzers perform this oxidation step by several processes:

• High temperature combustion
• High temperature catalytic oxidation (HTCO)
• Photo-oxidation alone
• Thermo-chemical oxidation
• Photo-chemical oxidation
• Electrolytic oxidation

High temperature combustion

Prepared samples are combusted at 1,200 °C in an oxygen-rich atmosphere. All carbon present converts to carbon dioxide, flows through scrubber tubes to remove interferences such as chlorine gas, and water vapor, and the carbon dioxide is measured either by absorption into a strong base then weighed, or using an infrared detector. Most modern analyzers use non-dispersive infrared (NDIR) for detection of the carbon dioxide. Compared to the conventional high temperature catalytic oxidation, the great benefit of the combustion-method is the high oxidation power, so that oxidation-promoting catalysts are superfluous.

High temperature catalytic oxidation

An HTCO combustion tube packed with platinum catalyst

A manual or automated process injects the sample onto a platinum catalyst at 680 °C in an oxygen rich atmosphere. The concentration of carbon dioxide generated is measured with a non-dispersive infrared (NDIR) detector.

Oxidation of the sample is complete after injection into the furnace, turning oxidizable material in the sample into gaseous form. A carbon-free carrier gas transports the CO₂, through a moisture trap and halide scrubbers to remove water vapor and halides from the gas stream before it reaches the detector. These substances can interfere with the detection of the CO₂ gas. The HTCO method may be useful in those applications where difficult to oxidize compounds, or high molecular weight organics, are present as it provides almost complete oxidation of organics including solids and particulates small enough to be injected into the furnace. The major drawback of HTCO analysis is its unstable baseline resulting from the gradual accumulation of non-volatile residues within the combustion tube. These residues continuously change TOC background levels requiring continuous background correction. Because aqueous samples are injected directly into a very hot, usually quartz, furnace only small aliquots (less than 2 milliliters and usually less than 400 micro-liters) of sample can be handled making the methods less sensitive than chemical oxidation methods capable of digesting as much as 10 times more sample. Also, the salt content of the samples do not combust, and so therefore, gradually build a residue inside the combustion tube eventually clogging the catalyst resulting in poor peak shapes, and degraded accuracy or precision, unless appropriate maintenance procedures are followed. The catalyst should be regenerated or replaced as needed. To avoid this problem the manufacturing industry has developed several concepts, such as matrix separation, ceramic reactors, better process control or methods without catalysts.

Photo-oxidation (ultraviolet light)

In this oxidation scheme, ultraviolet light alone oxidizes the carbon within the sample to produce CO₂. The UV oxidation method offers the most reliable, low maintenance method of analyzing TOC in ultra-pure waters.

Ultraviolet/persulfate oxidation

Like the photo-oxidation method, UV light is the oxidizer but the oxidation power of the reaction is magnified by the addition of a chemical oxidizer, which is usually a persulfate compound. The mechanisms of the reactions are as follows:

Free radical oxidants formed:

${\displaystyle \mathrm {S} _{2}\mathrm {O} _{8}^{2-}{\underset {hv}{\longrightarrow }}2\ \mathrm {SO} _{4}^{-\bullet }}$

${\displaystyle \mathrm {H} _{2}\mathrm {O} {\underset {hv}{\longrightarrow }}\mathrm {H} ^{+}+\mathrm {OH} ^{\bullet }}$

${\displaystyle \mathrm {SO} _{4}^{-\bullet }+\mathrm {H} _{2}\mathrm {O} \longrightarrow \mathrm {SO} _{4}^{2-}+\mathrm {OH} ^{\bullet }+\mathrm {H} ^{+}}$

Excitation of organics:

${\displaystyle \mathrm {R} {\underset {hv}{\longrightarrow }}\mathrm {R} ^{*}}$

Oxidation of organics:

${\displaystyle \mathrm {R} ^{*}+\mathrm {SO} _{4}^{-\bullet }+\mathrm {OH} ^{\bullet }\longrightarrow n\mathrm {CO} _{2}+\dots }$

The UV–chemical oxidation method offers a relatively low maintenance, high sensitivity method for a wide range of applications. However, there are oxidation limitations of this method. Limitations include the inaccuracies associated with the addition of any foreign substance into the analyte and samples with high amounts of particulates. Performing "system blank" analysis, which is to analyze then subtract the amount of carbon contributed by the chemical additive, inaccuracies are lowered. However, analyses of levels below 200 ppb TOC are still difficult.

Thermochemical persulfate oxidation

Also known as heated persulfate, the method utilizes the same free radical formation as UV persulfate oxidation except uses heat to magnify the oxidizing power of persulfate. Chemical oxidation of carbon with a strong oxidizer, such as persulfate, is highly efficient, and unlike UV, is not susceptible to lower recoveries caused by turbidity in samples. The analysis of system blanks, necessary in all chemical procedures, is especially necessary with heated persulfate TOC methods because the method is so sensitive that reagents cannot be prepared with carbon contents low enough to not be detected. Persulfate methods are used in the analysis of wastewater, drinking water, and pharmaceutical waters. When used in conjunction with sensitive NDIR detectors heated persulfate TOC instruments readily measure TOC at single digit parts per billion (ppb) up to hundreds of parts per million (ppm) depending on sample volumes.

Detection and quantification

Accurate detection and quantification are the most vital components of the TOC analysis process. Conductivity and non-dispersive infrared (NDIR) are the two common detection methods used in modern TOC analyzers.

Conductivity

There are two types of conductivity detectors, direct and membrane. Direct conductivity provides an all-encompassing approach of measuring CO₂. This detection method uses no carrier gas, is good at the parts per billion (ppb) ranges, but has a very limited analytical range. Membrane conductivity relies upon the filtering of the CO₂ prior to measuring it with a conductivity cell. Both methods analyze sample conductivity before and after oxidization, attributing this differential measurement to the TOC of the sample. During the sample oxidization phase, CO₂ (directly related to the TOC in the sample) and other gases are formed. The dissolved CO₂ forms a weak acid, thereby changing the conductivity of the original sample proportionately to the TOC in the sample. Conductivity analyses assume that only CO₂ is present within the solution. As long as this holds true, then the TOC calculation by this differential measurement is valid. However, depending on the chemical species present in the sample and their individual products of oxidation, they may present either a positive or a negative interference to the actual TOC value, resulting in analytical error. Some of the interfering chemical species include Cl⁻, HCO₃⁻, SO₃²⁻, SO₂⁻, ClO₂⁻, and H⁺. Small changes in pH and temperature fluctuations also contribute to inaccuracy. Membrane conductivity analyzers have improved upon the direct conductivity approach by incorporating the use of hydrophobic gas permeation membranes to allow a more “selective” passage of the dissolved CO₂ gas and nothing else. This provides a more precise and accurate measurement of the organics that were converted to CO₂.

Non-dispersive infrared (NDIR)

The non-dispersive infrared analysis (NDIR) method offers the only practical interference-free method for detecting CO₂ in TOC analysis. The principal advantage of using NDIR is that it directly and specifically measures the CO₂ generated by oxidation of the organic carbon in the oxidation reactor, rather than relying on a measurement of a secondary, corrected effect, such as used in conductivity measurements.

Plot of atmospheric transmittance in part of IR region showing CO₂ absorbing wavelengths

A traditional NDIR detector relies upon flow-through-cell technology, where the oxidation product flows into and out of the detector continuously. A region of absorption of infrared light specific to CO₂, usually around 4.26 µm (2350 cm⁻¹), is measured over time as the gas flows through the detector. A second reference measurement that is non-specific to CO₂ is also taken and the differential result correlates to the CO₂ concentration in the detector at that moment. As the gas continues to flow into and out of the detector cell the sum of the measurements results in a peak that is integrated and correlated to the total CO₂ concentration in the sample aliquot.

A new advance of NDIR technology is static pressurized concentration (SPC). The exit valve of the NDIR is closed to allow the detector to become pressurized. Once the gases in the detector have reached equilibrium, the concentration of the CO₂ is analyzed. This pressurization of the sample gas stream in the NDIR, a patented technique, allows for increased sensitivity and precision by measuring the entirety of the oxidation products of the sample in one reading, compared to flow-through cell technology. The output signal is proportional to the concentration of CO₂ in the carrier gas, from the oxidation of the sample aliquot. UV/ Persulfate oxidation combined with NDIR detection provides good oxidation of organics, low instrument maintenance, good precision at ppb levels, relatively fast sample analysis time and easily accommodates multiple applications, including purified water (PW), water for injection (WFI), CIP, drinking water and ultra-pure water analyses.

Analysers

Virtually all TOC analysers measure the CO₂ formed when organic carbon is oxidized and/or when inorganic carbon is acidified. Oxidation is performed either through Pt-catalyzed combustion, by heated persulfate, or with a UV/persulfate reactor. Once the CO₂ is formed, it is measured by a detector: either a conductivity cell (if the CO₂ is aqueous) or a non-dispersive infrared cell (after purging the aqueous CO₂ into the gaseous phase). Conductivity detection is only desirable in the lower TOC ranges in deionized waters, whereas NDIR detection excels in all TOC ranges. A variation described as "membrane conductometric detection can allow for measurement of TOC across a wide analytical range in both deionized and non-deionized water samples. Modern high-performance TOC instruments are capable of detecting carbon concentrations well below 1 µg/L (1 part per billion or ppb).

A total organic carbon analyser determines the amount of carbon in a water sample. By acidifying the sample and flushing with nitrogen or helium the sample removes inorganic carbon, leaving only organic carbon sources for measurement. There are two types of analysers. One uses combustion and the other chemical oxidation. This is used as a water purity test, as the presence of bacteria introduces organic carbon.

Analyser field testing and reports

A non-profit research and testing organization, the Instrumentation Testing Association (ITA) can provide results of field testing online TOC analysers in an industrial wastewater application. Gulf Coast Waste Disposal Authority (GCWDA), Bayport Industrial Wastewater Treatment Plant in Pasadena, Texas sponsored and conducted this test in 2011. The GCWDA Bayport facility treats approximately 30 mgd of industrial waste received from approximately 65 customers (primarily petrochemical). Field tests consisted of operating online TOC analysers at the influent of the Bayport facility in which TOC concentrations can range from 490 to 1020 mg/L with an average of 870 mg/L. GCWDA conducts approximately 102 TOC analyses in their laboratory per day at their Bayport treatment facility and use TOC measurements for process control and billing purposes. GCWDA plans to use online TOC analysers for process control, detecting influent slug loads from industries and to potentially use online TOC analysers to detect and monitor volatiles of the incoming stream. Field tests were conducted for a period of 90-days and used laboratory conformance measurements once per day to compare with analyser output to demonstrate the instrument's overall accuracy when subjected to many simultaneously changing parameters as experienced in real-time monitoring conditions. Field test results can provide information regarding instrument design, operation and maintenance requirements which influence the performance of the instruments in field applications. The field test report includes evaluations of online TOC analysers utilizing the following technologies: High temperature combustion (HTC), high temperature catalytic/combustion oxidation (HTCO), supercritical water oxidation (SCWO), and two-stage advanced oxidation (TSAO).

Combustion

In a combustion analyser, half of the sample is injected into a chamber where it is acidified, usually with phosphoric acid, to turn all of the inorganic carbon into carbon dioxide as per the following reaction:

CO₂ + H₂O ⇌ H₂CO₃ ⇌H⁺ + HCO₃⁻ ⇌ 2H⁺ + CO₃²⁻

This is then sent to a detector for measurement. The other half of the sample is injected into a combustion chamber which is raised to between 600–700 °C, some even up to 1200 °C. Here, all the carbon reacts with oxygen, forming carbon dioxide. It is then flushed into a cooling chamber, and finally into the detector. Usually, the detector used is a non-dispersive infrared spectrophotometer. By finding the total inorganic carbon and subtracting it from the total carbon content, the amount of organic carbon is determined.

Chemical oxidation

Chemical oxidation analysers inject the sample into a chamber with phosphoric acid followed by persulfate. The analysis is separated into two steps. One removes inorganic carbon by acidification and purging. After removal of inorganic carbon persulfate is added and the sample is either heated or bombarded with UV light from a mercury vapor lamp. Free radicals form persulfate and react with any carbon available to form carbon dioxide. The carbon from both determination (steps) is either run through membranes which measure the conductivity changes that result from the presence of varying amounts of carbon dioxide, or purged into and detected by a sensitive NDIR detector. Same as the combustion analyser, the total carbon formed minus the inorganic carbon gives a good estimate of the total organic carbon in the sample. This method is often used in online applications because of its low maintenance requirements.

Applications

TOC is the first chemical analysis to be carried out on potential petroleum source rock in oil exploration. It is very important in detecting contaminants in drinking water, cooling water, water used in semiconductor manufacturing, and water for pharmaceutical use. Analysis may be made either as an online continuous measurement or a lab-based measurement.

TOC detection is an important measurement because of the effects it may have on the environment, human health, and manufacturing processes. TOC is a highly sensitive, non-specific measurement of all organics present in a sample. It, therefore, can be used to regulate the organic chemical discharge to the environment in a manufacturing plant. In addition, low TOC can confirm the absence of potentially harmful organic chemicals in water used to manufacture pharmaceutical products. TOC is also of interest in the field of potable water purification due to byproducts of disinfection. Inorganic carbon poses little to no threat.

Analysis

Environmental

Since the early 1970s, TOC has been an analytic technique used to measure water quality during the drinking water purification process. TOC in source waters comes from decaying natural organic matter (NOM) as well as synthetic sources. Humic acid, fulvic acid, amines, and urea are examples of NOM. Some detergents, pesticides, fertilizers, herbicides, industrial chemicals, and chlorinated organics are examples of synthetic sources. Before source water is treated for disinfection, TOC provides an estimate of the amount of NOM in the water source. In water treatment facilities, source water is subject to reaction with chloride containing disinfectants. When the raw water is chlorinated, active chlorine compounds (Cl₂, HOCl, ClO⁻) react with NOM to produce chlorinated disinfection byproducts (DBPs). Researchers have determined that higher levels of NOM in source water during the disinfection process will increase the amount of carcinogens in the processed drinking water.

With passage of the U.S. Safe Drinking Water Act in 2001, TOC analysis emerged as a quick and accurate alternative to the classical but more lengthy biological oxygen demand (BOD) and chemical oxygen demand (COD) tests traditionally reserved for assessing the pollution potential of wastewaters. Today, environmental agencies regulate the trace limits of DBPs in drinking water. Recently published analytical methods, such as United States Environmental Protection Agency (EPA) method 415.3, support the Agency's Disinfectants and Disinfection Byproducts Rules, which regulate the amount of NOM to prevent the formation of DBPs in finished waters.

The content of TOC is also an important parameter to evaluate the quality of organic shale resources which are one of the most important unconventional fuels. Numerous evaluation methods have been introduced, including these based on wireline logs and in situ techniques.

Pharmaceutical

Introduction of organic matter into water systems occurs not only from living organisms and from decaying matter in source water, but also from purification and distribution system materials. A relationship may exist between endotoxins, microbial growth, and the development of biofilms on pipeline walls and biofilm growth within pharmaceutical distribution systems. A correlation is believed to exist between TOC concentrations and the levels of endotoxins and microbes. Sustaining low TOC levels helps to control levels of endotoxins and microbes and thereby the development of biofilm growth. The United States Pharmacopoeia (USP), European Pharmacopoeia (EP) and Japanese Pharmacopoeia (JP) recognize TOC as a required test for purified water and water for injection (WFI). For this reason, TOC has found acceptance as a process control attribute in the biotechnology industry to monitor the performance of unit operations comprising purification and distribution systems. As many of these biotechnology operations include the preparation of medicines, the U.S. Food and Drug Administration (FDA) enacts numerous regulations to protect the health of the public and ensure the product quality is maintained. To make sure there is no cross-contamination between product runs of different drugs, various cleaning procedures are performed. TOC concentration levels are used to track the success of these cleaning validation procedures.

Microelectronics

Organic contamination comes from multiple sources throughout the semiconductor manufacturing process. Organic residues left on the device can have negative effect on the wafer quality and impact wafer yield. The organics can also be a source of food for bacteria in the ultrapure water system. Due to the quality requirements of semiconductor water, TOC must be monitored at the parts per billion level. Continuous, on-line TOC analyzers play an important role in the monitoring of water systems to help provided a reliable indication of system health.

Cat behavior

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Cat_behavior 

Cat behavior includes body language, elimination habits, aggression, play, communication, hunting, grooming, urine marking, and face rubbing. It varies among individuals, colonies, and breeds.

Communication and sociability can vary greatly among individual cats. In a family with many cats, the interactions can change depending on which individuals are present and how restricted the territory and resources are. One or more individuals may become aggressive: fighting may occur with the attack resulting in scratches and deep bite wounds.

Communication

Main article: Cat communication

Kittens vocalize early in development. Some examples of different vocalizations are described below.

• Purring - means that the cat is either content or is self-soothing due to fear
• Meow - a frequently used greeting. A mother meows when interacting with her young.
• Hissing or spitting - indicates an angry or defensive cat.
• Yowl - means that the cat is in distress or feeling aggressive.
• Chattering - occurs when hunting or tracking potential prey. Consists of quick chirps made while the mouth vibrates. The gaze is fixed and staring. This behavior may be in response to a surge of adrenaline or may be caused by the anticipation of a pending hunt.

Body language

Cats greeting by rubbing against each other; the upright "question mark shape" tails also indicate happiness or friendship

Cats rely strongly on body language to communicate. A cat may rub against an object, lick a person, Much of a cat's body language is through its tail, ears, head position, and back posture.

The tail

Observing how a cat holds its tail can give a good sense of the cat’s current temperament.

• Held high, may have a slight curl forward - a sign of friendliness. The cat is happy, content, and comfortable. The tail may quiver or vibrate if the cat is excited.

• Held low and tucked under - a sign of fear or unease. The cat is attempting to make itself a smaller target to potential threats.

• Flicking, twitching - a sign of agitation. The cat is on high alert or is upset, and is not receptive to interaction. Cats may also flick their tails in an oscillating, snake-like motion, or abruptly from side to side, often just before pouncing on an object or animal. 

The eyes

When cats greet another cat in their vicinity, they can do a slow, languid, long blink to communicate affection if they trust the person or animal they are in contact with. It is a sign of trust. A way to communicate love and trust to your cat from a human perspective is to say their name, and get their attention, and then look them in the eyes and slowly blink at them to emulate trust and love, and they may return the gesture.

Scent rubbing and spraying

These behaviors are thought to be a way of marking territory. Facial marking behavior is used to mark their territory as "safe". The cat rubs its cheeks on prominent objects in the preferred territory, depositing a chemical pheromone produced in glands in the cheeks. This is known as a contentment pheromone. Synthetic versions of the feline facial pheromone are available commercially.

Cats have anal sacs or scent glands. Scent is deposited on the feces as it is eliminated. Unlike intact male cats, female and neutered male cats usually do not spray urine. Spraying is accomplished by backing up against a vertical surface and spraying a jet of urine on that surface. Unlike a dog's penis, a cat's penis points backward. Males neutered in adulthood may still spray after neutering. Urinating on horizontal surfaces in the home, outside the litter box may indicate dissatisfaction with the box, due to a variety of factors such as substrate texture, cleanliness and privacy. It can also be a sign of urinary tract problems. Male cats on poor diets are susceptible to crystal formation in the urine which can block the urethra and create a medical emergency.

Body postures

A cat's posture communicates its emotions. It is best to observe cats' natural behavior when they are by themselves, with humans, and with other animals. Their postures can be friendly or aggressive, depending upon the situation. Some of the most basic and familiar cat postures include the following:

• Relaxed posture – The cat is seen lying on the side or sitting. Its breathing is slow to normal, with legs bent, or hind legs laid out or extended. The tail is loosely wrapped, extended, or held up. It also hangs down loosely when the cat is standing.
• Stretching posture – another posture indicating the cat is relaxed.
  

• Cat yawning posture
• Yawning posture – either by itself, or in conjunction with a stretch: another posture of a relaxed cat.
• Alert posture – The cat is lying on its belly, or it may be sitting. Its back is almost horizontal when standing and moving. Its breathing is normal, with its legs bent or extended (when standing). Its tail is curved back or straight upwards, and there may be twitching while the tail is positioned downwards.
• Tense posture – The cat is lying on its belly, with the back of its body lower than its upper body (slinking) when standing or moving back. Its legs, including the hind legs are bent, and its front legs are extended when standing. Its tail is close to the body, tensed or curled downwards; there can be twitching when the cat is standing up.
• Anxious/ovulating posture – The cat is lying on its belly. The back of the body is more visibly lower than the front part when the cat is standing or moving. Its breathing may be fast, and its legs are tucked under its body. The tail is close to the body and may be curled forward (or close to the body when standing), with the tip of the tail moving up and down (or side to side).
• Fearful posture – The cat is lying on its belly or crouching directly on top of its paws. Its entire body may be shaking and very near the ground when standing up. Breathing is also fast, with its legs bent near the surface, and its tail curled and very close to its body when standing on all fours.
• Confident posture – The cat may walk around in a more comfortable manner with its tail up to the sky indicating their importance. Cats often walk through houses with their tail standing up high above them making them look grander and more elegant.
• Terrified posture – The cat is crouched directly on top of its paws, with visible shaking seen in some parts of the body. Its tail is close to the body, and it can be standing up, together with its hair at the back. The legs are very stiff or even bent to increase their size. Typically, cats avoid contact when they feel threatened, although they can resort to varying degrees of aggression when they feel cornered, or when escape is impossible.

• 

  Relaxing cat

• 

  Stretching cat

• 

  Yawning cat

• 

  Yawning kitten

• 

  Alert cat

• 

  Tense cat

• 

  Fearful cat

• 

  Terrified cat

Grooming

Play media

Cat grooming itself.

Oral grooming for domestic and feral cats is a common behavior; recent studies on domestic cats show that they spend about 8% of resting time grooming themselves. Grooming is extremely important not only to clean themselves but also to ensure ectoparasite control. Fleas tend to be the most common ectoparasite of cats and some studies allude to indirect evidence that grooming in cats is effective in removing fleas. Cats not only use their tongue for grooming to control ectoparasites but scratch grooming as well may aid in dislodging fleas from the head and neck.

Kneading

Main article: Kneading (cats)

 

Play media

Classic kneading of a cat

Kittens "knead" the breast while suckling, using the forelimbs one at a time in an alternating pattern to push against the mammary glands to stimulate lactation in the mother.

Cats carry these infantile behaviors beyond nursing and into adulthood. Some cats "nurse", i.e. suck, on clothing or bedding during kneading. The cat exerts firm downwards pressure with its paw, opening its toes to expose its claws, then closes its claws as it lifts its paw. The process takes place with alternate paws at intervals of one to two seconds. They may knead while sitting on their owner's lap, which may prove painful if the cat has sharp claws.

Since most of the preferred "domestic traits" are neotenous or juvenile traits that persist in the adult, kneading may be a relic juvenile behavior retained in adult domestic cats. It may also stimulate the cat and make it feel good, in the same manner as a human stretching. Kneading is often a precursor to sleeping. Many cats purr while kneading. They also purr mostly when newborn, when feeding, or when trying to feed on their mother's teat. The common association between the two behaviors may corroborate the evidence in favor of the origin of kneading as a remnant instinct.

Panting

A cat panting

Unlike dogs, panting is a rare occurrence in cats, except in warm weather environments. Some cats may pant in response to anxiety, fear or excitement. It can also be caused by play, exercise, or stress from things like car rides. However, if panting is excessive or the cat appears in distress, it may be a symptom of a more serious condition, such as a nasal blockage, heartworm disease, head trauma, or drug poisoning. In many cases, feline panting, especially if accompanied by other symptoms, such as coughing or shallow breathing (dyspnea), is considered to be abnormal, and treated as a medical emergency.

Reflexes

Righting reflex

Main article: Cat righting reflex

 

Chronophotography of a falling cat by Étienne-Jules Marey, 1894

The righting reflex is the attempt of cats to land on their feet at the completion of a jump or a fall. They can do this more easily than other animals due to their flexible spine, floating collar bone, and loose skin. Cats also use vision and their vestibular apparatus to help tell which way to turn. They can then stretch themselves out and relax their muscles. The righting reflex does not always result in the cat landing on its feet at the completion of the fall.

Freeze reflex

Adult cats are able to make use of pinch-induced behavioural inhibition to induce a 'freeze reflex' in their young which enables them to be transported by the neck without resisting. This reflex can also be exhibited by adults. This is also known as 'clipnosis'.

Eating patterns

Cat eating "cat grass"

Cats are obligate carnivores, and do not do well on vegetarian diets. In the wild they usually hunt smaller mammals to keep themselves nourished. Many cats find and chew small quantities of long grass but this is not for its nutritional value per se. The eating of grass seems to stem from feline ancestry and has nothing to do with dietary requirements. It is believed that feline ancestors instead ate grass for the purging of intestinal parasites.

Cats have no sweet taste receptors on their tongue and thus cannot taste sweet things at all. Cats mainly smell for their food and what they taste for is amino acids instead. This may be a cause of cats being diagnosed with diabetes. The food that domestic cats get has a lot of carbohydrates in it and a high sugar content cannot be efficiently processed by the digestive system of cats.

Cats drink water by lapping the surface with their tongue. A fraction of a teaspoon of water is taken up with each lap. Although some desert cats are able to obtain much of their water needs through the flesh of their prey, most cats come to bodies of water to drink.

Eating patterns is another indicator to understand the behavior changers in domestic cats. The changers in typical eating patterns can be a early signal for possible physical or psychological health problem. 

A cat's eating pattern in domestic settings are essential for the cat and owner bond to form. This happens because cats form attachments to households that regularly feed them. Some cats ask for food dozens of times a day, including at night, with rubbing, pacing, and meowing, or sometimes loud purring.

Excretion

Cats tend to bury their feces after defecating and can be attracted to a litter box if it has attractant in it. Cats will generally defecate more in those litter boxes too.

Socialization

Socialization is defined as a member of a specific group learning to be part of that said group. It is said to be a continuous learning process that allows an individual to learn the necessary skills and behaviours required for a particular social position.

Cats, domestic or wild, do participate in social behaviours, even though it is thought that most cat species (besides lions) are solitary, anti-social animals. Under certain circumstances, such as food availability, shelter, or protection, cats can be seen in groups.

The social behaviours that cats participate in are colony organization, social learning, socialization between cats, and socialization with humans.

Colony organization

Free-living domestic cats tend to form small to large colonies. Small colonies consist of one female, known as a queen, and her kittens. Large colonies consist of several queens and their kittens. Male cats are present in both types of colonies and serve the purpose of reproduction and defending territory. Within these colonies altruistic behaviour occurs. This means that if an expecting queen helps another queen that just gave birth, then the helping queen will get help when she gives birth in return.

Although free living cats are found in colonies, stable social order, like that of the lion, does not exist. Free living cats usually are found in colonies for protection against predators, and food availability. Although there are many advantages of group living, such as easy access to mates, and defensive measures to protect food, there are also disadvantages, such as sexual competition for mates, and if the group becomes too big then fights may break out over food.

Social learning

Cats are observational learners. This type of learning emerges early in a cat's life, and has been shown in many laboratory studies. Young kittens learn to hunt from their mothers by observing their techniques when catching prey. The mother ensures their kittens learn hunting techniques by first bringing dead prey to the litter, then live prey. With the live prey, she demonstrates the techniques required for successful capture to her kittens by bringing the live prey to the litter for the kittens to catch themselves. Prey-catching behaviour of kittens improves over time when mothers are present over when they are not.

Observational learning for cats can be described in terms of the drive to complete the behaviour, the cue that initiates the behaviour, the response to the cue, and the reward for completing the behaviour. This is shown above when cats learn predatory behaviour from their mothers. The drive is hunger, the cue is the prey, the response is to catch the prey, and the reward is to relieve the hunger sensation.

Kittens also show observational learning when they are socializing with humans. They are more likely to initiate socialization with humans when their mothers are exhibiting non-aggressive and non-defensive behaviours. Even though mothers spend most time with their kittens, male cats play an important role by breaking up fights among litter mates.

Observational learning is not limited to kitten-hood, it can also be observed during adulthood. Studies have been done with adult cats performing a task, such as pressing a lever after a visual cue. Adult cats that see others performing a task learn to perform the same task faster than those who did not witness another cat.

Socialization between cats

When strange cats meet, ideally they would cautiously allow the strange cat to smell its hindquarters, but this does not happen very often. Usually when strange cats meet, one cat makes a sudden movement that puts the other cat into a defensive mode. The cat will then draw in on itself and prepare to attack if needed. If an attack were to happen the subordinate cat will usually run away, but this does not happen all the time and it could lead to a tomcat duel. Dominance is also seen as an underlying factor for how conspecifics interact with each other.

Dominance

Dominance can be seen among cats in multi-cat households. It can be seen when other cats submit to the "dominant" cat. Dominance includes such behaviours as walking around the dominant cat, waiting for the dominant cat to walk past, avoiding eye contact, crouching, laying on their side (defensive posture), and retreating when the dominant cat approaches. Dominant cats present a specific body posture as well. The cat displays ears straight up, the base of its tail will be arched, and it looks directly at subordinate cats. These dominant cats are usually not aggressive, but if a subordinate cat blocks food they may become aggressive. When this aggressive behaviour occurs it could also lead to the dominant cat preventing subordinate cats from eating and using the litter box. This can cause the subordinate cat to defecate somewhere else and create problems with human interaction.

Social conflicts

Two cats fighting

Social conflicts among cats depend solely on the behaviour of the cats. Some research has shown that cats rarely pick fights, but when they do its usually for protecting food and/or litters, and defending territory.

The first sign of an imminent tomcat duel is when both cats draw themselves up high on their legs, all hair along the middle of their backs is standing straight up, and they mew and howl loudly as they approach one another. The steps the cats make become slower and shorter the closer they become to one another. Once they are close enough to attack, they pause slightly, and then one cat leaps and tries to bite the nape of the other cat. The other cat has no choice but to retaliate and both cats roll aggressively on the ground, and loud intense screams come from both cats. After some time the cats separate and stand face to face to begin the attack all over again. This can go on for some time until one cat does not get up again and remains seated. The defeated cat does not move until the victor has completed a sniff of the area and moves outside the fighting area. Once this happens the defeated cat leaves the area, ending the duel.

Females may also fight with each other. If a male and female do not get along, they may also fight. Cats may need to be reintroduced or separated to avoid fights in a closed household.

Socialization with humans

Cats have learned how to develop their vocals in order to converse with humans, in which they try to tell humans what they want. One way that cats and humans interact is through "head bunting," in which a cat rubs its head on a human in order to leave their scent, mark to claim territory, and create a bond.

Cats between the age of three to nine weeks are sensitive to human socialization; after this period socialization can be less effective. Studies have shown that the earlier the kitten is handled, the less fearful the kitten will be towards humans. Other factors that can enhance socialization are having many people handle the kitten frequently, the presence of the mother, and feeding. The presence of the mother is important because cats are observational learners. If the mother is comfortable around humans then it can reduce anxiety in the kitten and promote the kitten-human relationship.

Feral kittens around two to seven weeks old can be socialized usually within a month of capture. Some species of cats cannot be socialized towards humans because of factors like genetic influence and in some cases specific learning experiences. The best way to get a kitten to socialize is to handle the kitten for many hours a week. The process is made easier if there is another socialized cat present but not necessarily in the same space as the feral. If the handler can get a cat to urinate in the litter tray, then the others in a litter will usually follow. Initial contact with thick gloves is highly recommended until trust is established, usually within the first week. It is a challenge to socialize an adult. Socialized adult feral cats tend to trust only those who they trusted in their socialization period, and therefore can be very fearful around strangers.

Cats are also used for companion animals. Studies have shown that these animals provide many physiological and psychological benefits for the owner. Other aspects of cat behaviour that are deemed advantageous for the human–cat bond are cat hygiene (cats are known for good hygiene), they do not have to be taken outside (use of the litter box), they are perfect for smaller spaces, and they have no problems with being left alone for extended periods of time. Even though there are a number of benefits for owning a cat, there are a number of problematic behaviours that affect the human–cat relationship. One behaviour is when cats attack people by clawing and biting. This often occurs spontaneously or could be triggered by sudden movements. Another problematic behaviour is the "petting and biting syndrome", which involves the cat being petted and then suddenly attacking and running away. Other problems are house soiling, scratching furniture, and when a cat brings dead prey into the house. It is these kinds of behaviours that put a strain on the socialization between cats and people.

There are 52 measured cat personality traits in cats, with one study suggesting "five reliable personality factors were found using principal axis factor analysis: neuroticism, extraversion, dominance, impulsiveness and agreeableness."

Predatory behavior

Cats are natural predators. When allowed to roam outdoors, many cats will engage in predation on wildlife. Understanding an indoor cat's personality can go a long way to satisfy their instincts and avoid potentially inconvenient behavior (such as sudden hissing, dashing around the house, or climbing the curtains). Environmental enrichment items include:

• A good-sized cat tree, with scratching posts
• Toys that provide a release for their predatory instincts
• A well kept litter box or toilet
• Fresh water and dry cat food
• Social interaction

Environment

Cats like to organize their environment based on their needs. Like their ancestors, domestic cats still have an inherent desire to maintain an independent territory but are generally content to live with other cats for company as they easily get bored. Living alone for a longer time may cause them to forget how to communicate with other cats.

Sometimes, however, adding a kitten to a household can be a bad idea. If there already is an older cat present and another cat is added to their environment it may be better to get another older cat that has been socialized with other cats. When a kitten is introduced to a mature cat, that cat may show feline asocial aggression where they feel threatened and act aggressive to drive off the intruders. If this happens, the kitten and the cat should be separated, and slowly introduced by rubbing towels on the animals and presenting the towel to the other.

Cats use scent and pheromones to help organize their territory by marking prominent objects. If these objects or scents are removed it upsets the cat's perception of its environment.