Methodologies in Wastewater Minimization

Abstract

Wastewater is an environmental problem. Managing it is one of the many challenges engineers of refineries and oil complexes have to cope with. However, once it is resolved and adequate measures and activities have been instituted, it can help in the form of savings for the company and the solution of environmental issues.

Wastewater is usually produced by process industries that consume large amounts of water. It carries chemicals and toxic substances, but when properly treated, it can be reused for other purposes.

On the contrary, the process of wastewater minimization is quite complicated and some are costly if not properly implemented. Application of wastewater minimization should conform to existing laws and regulations of different states. A well-known technique is the water pinch technology, which is the analysis of the presence of contaminants and toxic chemicals in the water, such as hydrocarbon components.

Water pinch technology is used in the analysis of the lowest flowrate target for the consumption of freshwater. Industries have reported several successes in its implementation.

Discussed in this paper are the methods of wastewater minimization. The entire process has to follow procedures mandated by the Clean Water Act. Other methods include separation by gravity, a natural process of separating oil from water. Nitrification is a biological process, which is commendable because it provides good results but is costly. Reverse osmosis is used in separating minerals from seawater and puts into action the method of natural osmosis in the reverse.

There are some practical methods of wastewater minimization discussed in this paper.

Introduction

Wastewater is produced by refineries and process industries as an aftermath of rows of production using water and other chemical substances. Contamination with chemicals and toxic substances is inevitable, and therefore, before wastewater has to be discharged or disposed to the environment and mixed with other bodies of water, it has to be treated, neutralizing the toxic substances and making it reusable for other purposes.

Wastewater is a threat to the environment. States have formulated environmental laws to minimize wastewater and to regulate its disposal. Several methods are being implemented by refineries for the eventual reuse of wastewater.

Refineries and industries, which produce large amounts of wastewater, have to comply with local and federal laws. They have programs for wastewater treatment and minimization by existing environmental laws in their respective states.

This essay will provide an in-depth analysis of some of the technologies already available.

Refineries and process industries discharge wastewater at an unprecedented speed, and if wastewater is not treated first before being discharged to the adjoining body of water, it could create an environmental catastrophe. Awareness of environmental issues has motivated some companies around the world to find solutions in the form of technological innovations or inventions to minimize the production of wastewater so that they can reuse it after treatment. However, making wastewater reusable requires several complicated processes. Contaminants have to be separated and dissolved from water.

Contaminants and toxic chemicals with hydrocarbon components are found in the wastewater. Substances like petroleum hydrocarbons impart undesirable taste and affect aquatic organisms. A mixture of water and gasoline is very toxic and harmful to the environment; this is usually present in ships and is difficult to separate. Naphthenic acid is a substance found in wastewater that is harmful to plant and animal life, while other poisonous substances like hydrocarbons cause cancer to humans and animals, and alter the ecological balance. Animals that drink contaminated oil get seriously ill in their alimentary tract. (Khezri, Lotfi, Tabbian, & Erfani, 2010, p. 281)

In some countries, for example, India, the public and private sectors are involved in preserving the environment through wastewater management. An organization known as Central Leather Research Institute (CLRI), which is in charge of promoting the aims and objectives of the leather industry in India, has introduced measures for wastewater minimization, which led to approval of some with intellectual property rights. The measures mostly introduced wastewater treatment and reuse. Some of them are:

  • A method of removing phenol from phenol-bearing wastewater, which uses pseudomonas pictorum from a rice bran and carbon;
  • Purifying tannery effluents
  • Purifying inorganic nitrogen in water
  • Purifying Escherichia coli contaminated water
  • Recovering salt from salt-laden water for reuse
  • A process for preparing carbon polymer mixed with metal. (Chemical Business, 2006, p. 57)

Methods used in wastewater analysis

There are various techniques for the treatment of wastewater. But first, wastewater has to be analyzed. One of the techniques used to analyze wastewater is the water pinch technology. (Mohammadnejad, Bidhendi and Mehrdadi, 2011, p. 88)

The principle used in water pinch analysis is the application of contaminants; in other words, this is a battle between contaminants. The process involves applying contaminants to eliminate the present contaminants which are harmful to the environment. The application of one or a mass of contaminants requires several methods, which may be mathematical, graphical, or computer-based. (Mohammadnejad et al., 1011, p. 89)

Water pinch technology allows an analysis of the lowest flowrate target for consumption of freshwater and generation. It has been used by engineers in their analysis of water-using networks and effluent treatment systems. (Mann and Liu, 1999, p. xi; Mohammadnejad et al., 2011, p. 89)

Companies that have been applying water pinch technology have reported successes, particularly in savings. One company, the Monsanto Company, reported having attained savings and reduction of freshwater usage by at least 30 percent. Water-pinch technology has become popular and has since been applied in commercial and research applications.

Oil has to be separated from the water to make it reusable. The Clean Water Act requires an effluent concentration of 10mg/L or less, otherwise this does not meet the stringent measures of the law. More than 10mg/L of effluent concentration allows for sheen to develop at the surface of the water, suggesting the presence of hydrocarbon in the water. In ships, wastewater has to be carefully treated before it can be discharged to the sea and to the environment. Wastewater in ships comes from the ballast which is contaminated with hydrocarbon and other contaminants.

Separation by Gravity

The natural way of separating oil from water is through a process using gravity. It is done by means of flotation of the oil droplets above the water. The process involves the natural gravitational separation which is being executed in big tanks. The enhanced gravitational separation can be executed by using centrifugal force, while other refineries use distillation. (Veenstra, Mohr & Sanders, 1998, p. 6)

The process of water treatment uses several stages of biological removal reactors. The first stage, which utilizes the sequential batch reaction, includes the removal of oil and grease and other hydrocarbons emitted by petroleum substances. The second stage utilizes a submerged fixed-film, a kind of biological reactor, which is used to spread the sulfur-oxidizing bacteria to produce the effluent quality of the water by eliminating the organic sulfur compounds. The succeeding stage is nitrification which involves removing the ammonia. (Peeters & Theodoulou, 2005)

Nitrification

Nitrification is a complicated biological process that converts nitrates into nitrogen gas. Nitrogen can be found in the water in the form of other substances. Treatment system in this kind of wastewater involves several storage tanks, bio-reactors, and other filters and storage equipment. (Shulder et al., 2010, p. 62)

Reverse Osmosis

This is used for separating minerals from seawater. Reverse osmosis has not been popularly used because of the high cost of its application. The process puts into action the method of natural osmosis in the reverse. The water passes through a thin skin surface that is applied with an amount of pressure, allowing the water to produce 25 percent concentrate of pure water. (Isaák, Söjtöri, Kondor, & Gyôry, 2008, p. 125; Shao, 2008)

Microfiltration

The process involves an organic polymer with even pore dimensions, applied to the water to hold smaller particles that have smaller pores. It can retain the bacteria but cannot separate colloidal materials. (Isaák et al., 2008, p. 129)

Nanofiltration

Nanofiltration uses nanofilters to remove dissolved molecules even down to the smallest molecular mass of treated water. The nanofillers have extremely small pore diameters that exert operational pressure greater than other filters like the ultrafilter. (Isaák et al., 2008, p. 129)

Ultrafiltration

This is almost similar to microfilters but has different pore diameters ranging from 0.0015 – 0.2 micrometer particles in size. The water which has been applied with ultrafiltration does not need sterilization but can be used for industrial purposes.

Types of separators

The API Separators

One technique of separating oil from water is by using oil separators or API. This process uses constructed pits wherein wastewater streams are directed to a single sewer system and into the pits, and then the oil is separated from the water. There are some imperfections in this process because the resultant water is still contaminated with substances. Cooling water in refineries also carries oil, and this can be dangerous to the environment if it is not properly executed.

API Separators can actually remove 150 micron and other large droplets to lower the level of oil concentration, probably about 150 mg/L. Using API separators does not meet the requirements of the Clean Water Act. An API separator does not perform the specifications predicted by Stokes’s law.

The Stokes’s law is used to determine the properties of the fluid. The equation formulated by the mathematician George Gabriel Stokes states: F=6(pi)RnVc, whereby R represents the radius of a particular sphere, which is to be multiplied with n the viscosity, and the Vc or the velocity of the fluid.

There are a number of significant variables to Stokes’s equation. Stokes’s law has the objective of describing the motion of solid particles as they fall in a liquid. The viscosity of the continuous liquid, along with the droplet and its size should be known. The equation involves finding the value of the size of the separator and the rise velocity.

Flocculation units

This action uses chemicals with aluminum or ferric salts and can only be done when there are suspended solid particles still present after the action of the gravity separation. The flocculants are mixed with and circulated in the water. The advantage to this kind of action is that the sulfides can be removed with the solid particles and low levels of hydrocarbon can be attained. However, the action can also produce large quantities of hydrocarbon with sludge.

Air flotation (DAF and IAF)

This is effective in treating wastewater that cannot be treated by gravity. Using DAF or IAF systems can remove heavy oil and solid particles in the water. The process uses flotation aids like the usual coagulants and flocculants. The use of air flotation has been recommended by many authors because of the relative economy of space it can provide and the short time needed to impound the wastewater. (Lavallee and Nadreau, 1997, cited in Rigas et al., 2000, p. 245)

Coalescing plate separators

This process reduces the distance that droplets can go before they are being seized. The size of the separators is also reduced here. One technique in this method is to tilt the separator to minimize too much space. Commercial types of this kind are available and some companies sell patented coalescing plate separators.

Multiple angle separators

This is an improvement of the coalescing plate separator wherein the action done is plugging the solid particles in the wastewater with oil.

Examples of wastewater minimization applied by industries

The example of Brazil

Brazil is one of the countries that suffer from water pollution and has been trying to minimize wastewater caused by industries. Brazil’s population has already reached 170 million. However, Brazil implemented some safe and commendable measures for wastewater management. At the turn of the century, Brazil set up the National Water Agency, an agency of the government that looks after water recovery or reuse, controls the pollution of its rivers and bodies of water, installs treatment plants, and consequently finds ways for funding of its various programs of wastewater minimization. (Kujawski, 2009)

Treatment of wastewater involves the reduction of BOD (biochemical oxygen demand) loads, and permitting an allowable load which is 60 mg/l. (Oliveira, Parkinson, & Sperling, 2006, p. 245)

Pakistan refinery: Attock Refinery Ltd.

The Attock Refinery in Pakistan produces a great amount of oily and non-oily wastewater streams that carry wastewater to the facilities. The company processes four crude mixes which range from light-sweet, light-sour, heavy and high total acid number crude oil. It uses crude distillation units in its processing of wastewater. (Ahmed et al., 2009)

Oily wastewater passes through the boilers then through oil-water separators, and onto the equalization tank. The oil is separated and sent to a primary treatment composed of the slant-rib coalescer (SRC), and the dissolved air flotation (DAF).

Meticulous processThe Pakistan government has enforced strict environmental laws, one of which is the Environmental Protection Act of 1997. The Act limits pH and oil & grease (O&G) in wastewater. The regulatory body sees to it that wastewater technology corresponds to the stipulations of the law. Before the implementation of the wastewater technology, Attock Refinery Limited violated the standards, but after continuous consultations and enforcements, the refinery has now complied and promoted the objectives of the regulatory board. (The Gazette of Pakistan, 1997)

The technology implemented by ARL controls pH, including total suspended solids or TSSs, O&G and COD. The first step analyzes the parameters in the effluent streams in order to determine the outcome and impact these have created on the main effluent streams. In its demonstration, the majority of the pH and TSS values come from the boiler blowdown water. This amount of water passes through the non-oily stream. Amounts of pH, COD, and O&G mostly come from the wastewater stream, and the oily stream caused a great effect on the pre-treatment process. A great amount of oil can be found in the heavy crude unit.

The wastewater treatment process is done in the following method:

  • Water coming from the three boilers and softener backwash contains a great amount of TSS and TDSs or total dissolved solids. The pH 12 does not meet the standards. ARL used water treatment chemicals such as phosphate, sulfate and ammonia to control the pH. Before treatment, the wastewater is sent to the non-oily wastewater stream, first mixing this with treated oily wastewater, and then the water is flowed out of the refinery. (Ahmed et al., 2009)
  • Spent caustic is a result of the naphtha treatment. The process results in what is termed sour naphtha and kerosene. When the chemical alkyl mercaptans were added to the naphtha and kerosene, it resulted in alkyl disulfides. When a catalyst was added into mercaptans and other nitrogen compounds, the chemicals were dissolved.
  • In the treatment process, 3% caustic strength was used for naphtha/kerosene, a process before washing, and 8%-10% for the settler. For the naphtha 8-10% settler, the quantity was 6.5 m3 at 6-time monthly disposal. This is shown in their “sources and quantity of caustic drainage”.
  • The cooling towers created a stream going to the non-oily one. This concerns the concentration of pH, TSSs, TDSs, COD and O&G. The process used chemicals such as phosphate, biospheres and deosperse, and others that control pH. (Ahmed et al., 2009)

Continuous analysis was conducted on the boiler with the blowdown water that produced neutralization. Sulfuric acid was used to reduce costs and further enhance chemical consumption. A very small quantity of H2SO4, about 0.4 ml, which was approximately 98%, per liter of boiler blowdown water (BBDW), was needed to bring down a pH < 9. This is in accordance with Pakistan’s standards. According to laboratory analysis, high COD values were produced by the oily portion from the spent caustic, caused by the sweetening process. The oily layer had to be removed, reducing 80% to 90% reduction of caustic COD. What remained of the spent caustic was mixed with the rest of the water going down.

A pit was constructed, with a capacity of 0.1 million gallons. The purpose of this was to provide room for the water coming from the boiler. Wastewater coming from the boiler had a controlled temperature of 80° to 90°C. A cooling process of two hours occurred in the first two pits. Then the spent caustic was pumped to the next half of the pit reaching a rate of 1 tpd. Sulfuric acid was added to the wastewater to allow the pH to reach 8. The water would then pass to the third or fourth portions of the pit before it is exited. Operation made the use of desalter oil. Wastewater separation was successful.

Wastewater minimization in Saudi Arabia

Saudi Arabia is one of the richest in the world when it comes to oil, but water is its major problem. It produces too much wastewater, and depends on desalination for potable water. Desalination however is very costly so the country has to find ways to process water for its drinking population and industrial needs. The cost of desalination amounts to 6 Saudi riyals for every cubic meter of water. Reused water can provide a lot of savings for the government and for the Saudi people. It can also help improve and protect the environment and prevent global warming. (Ministry of Economy, Trade, and Industry, 2009)

The Ministry of Economy, Trade, and Industry (2009) commissioned a study that later found that in Saudi Arabia, there are five oil refineries, with the Riyadh Refinery Plant as one of the biggest refineries. The refinery has wastewater treatment plants, which are not found in the same location but are several kilometers apart. Their treatment facilities treat secondary water from the cooling tower, boiler feed water, and so forth. The Riyadh Refinery takes its water from the secondary treated water.

The application of wastewater reuse at Saudi Aramco has reduced the cost of industrial water because of the application of excellent technology by experienced Saudi engineers and experts. Regulations and standards for the preservation and protection of the environment, especially on wastewater management and oil and water separation, are being enforced by the Presidency of Meteorology and Environment Regulations and Standards. (Ministry of Economy, Trade and Industry, 2009)

Wastewater treatment in a refinery

One example of wastewater treatment is that of the Philippine refinery water treatment system which was applied with a multiple-angle coalescing system. The process was done in which the separator pits were upgraded to DAF chambers, and a dug-out was made to perform the action of impounding the wastewater. To be treated was 2500 gpm of wastewater from the tanks and the ships’ ballast in the refinery, but there was an added 5000 gpm of stormwater. The system was installed to purposely remove the oil along with the solids, phenols and other undesirable substances. In this process, hydrocarbons were retained in the large tanks while excess water flowed to the ocean through Manila Bay. (MBendi Information Services, 2010)

The Shuaiba Industrial Complex

The Shuaiba Industrial Area (SIA) in Kuwait is the largest industrial complex in the area. Situated in the complex are petrochemicals, oil refineries, and other large commercial and industrial corporation headquarters. The Suaiba Area Authority is the government arm responsible for wastewater management and transforming wastewater into something clean and useful. The objective is to make the wastewater reusable for industrial and agricultural purposes. (Al-Muzaini, 1997, p. 57-8)

The Suhaiba area generates a great amount of water, an estimated 3,000 m3/d of sanitary wastewater, but could reach up to 50,610 m3/d. The processors of the SIA include bar screens, parallel plate separators, filtration and chlorine disinfection. (Al-Muzaini, 1997, p. 59)

The sanitary wastewater was collected by a gravity sewer system, but wastewater had been discharged without treatment into the open sea. This caused environmental problems. At present, the area uses septic tanks in discharging some 15% of sanitary wastewater. Sea cooling water is used for cooling the wastewater, then it is treated and discharged to the open sea. Treated wastewater in the Shuaiba area is now being used for various purposes such as landscape irrigation, industrial and sanitary uses.

The Shuaiba Area Authority wastewater management has produced cost-effective methods, so that establishments and refineries can conform to government regulations on wastewater reuse. SAA has developed regulations and codes to guide the treatment of wastewater and eventual reuse of wastewater. Following the rules of the SAA, the SIA has produced sanitary wastewater that can be used for landscape irrigation. This is very much needed by Kuwait since the area has less rainfall throughout the year.

The Duna Refinery

The Duna Refinery wastewater management has been continuously upgraded to meet the demands of wastewater reuse. The refinery met the specifications of the EU regulations. It has recently upgraded its wastewater treatment plant with the introduction of a state-of-the-art dissolved air flotation unit cyclic activated sludge (CASS) and biological grade which is automatic. (Isaák et al., 2008, p. 125)

The Duna Refinery has to comply with European standards on wastewater management in order to reduce environmental pollution and abuse of Europe’s water reserves. The European Committee instituted the Best Available Techniques program (BAT) to minimize environmental effects from commercial establishments such as those processing oil and other pollutant-producing businesses. Using the BAT means enterprises should have adequate knowledge of the environmental performance of the business and the corresponding best solutions.

Under the BAT regulations, a refinery should have a wastewater treatment system to manage and treat chemicals and pollutants in the wastewater and can discharge wastewater, or process crude oil to a maximum of 1, or between 0.5 to 1.0. It is estimated that the Duna Refinery is about 1.38 which is beyond the requirement of the BAT. (Isaák et al., 2008, p. 125)

The Petromidia Refinery Complex

This refinery complex in Romania has a petroleum refinery and petrochemical plant. Wastewater management involves processing 4.8 million tons of crude oil annually. The complex produces oil derivatives such as diesel fuel, jet fuel and other kinds of fuel for various business applications. The refinery needs proper wastewater management to reduce environmental impact, minimize costs in operations and go for the reuse of treated wastewater. Water source for the complex is from the Danube-Black Sea Channel, and the process water is pumped at a rate of 1,700 cubic meters per hour. (Rompetrol Refinery Complex, 2002)

Improved water management was implemented by a team that generated benefits like the reduction of costs in environmental compliance, optimization of energy consumption and equipment, and reduction of wastewater from the plant to the open water. Improvement of wastewater management was implemented by a team who saw it fit to create a plan first before they had to implement something. They formulated the step-by-step process to improve the company’s wastewater management.

They developed an effective information-gathering technique. Like any other activity, information was focused on their particular objective, water management. They gathered information on water use, how wastewater was produced, processed, and treated. Important data on flow rates were obtained from the various plant sites. They also took water samples to determine the characteristics of the water from the plants.

They developed and analyzed some methods to improve water management. They also focused on improving equipment design, rehabilitation of existing structures, and other modifications. The team conducted awareness and training on the personnel and workers present inside the plant. Finally, they developed an implementation plan for their recommendations. Various benefits can be derived for the improvement of wastewater management, but the best benefit points to environmental preservation.

Discussion

There is a big demand for wastewater reuse in refineries and oil complexes around the world. Freshwater from streams and natural resources is already depleted. We have to optimize the reuse of water; otherwise, there will be a big scarcity of water. In many areas around the globe, water is a great necessity. In our existence, the need for water is equal to the need for food.

One of the solutions for the lack of water is to recycle, or treat wastewater so it can be further of use. Treated wastewater can be used for other purposes such as landscape irrigation, watering plants, and industrial purposes. (Shao, 2008)

Discussed in this paper are the various wastewater minimization techniques implemented by process industries and refineries. As stated in the introductory part, this paper’s objective is to evaluate the methods of wastewater treatment in refineries and how wastewater could be reused for other purposes.

Environmental danger and harm posed by process industries and commercial establishments throughout the world have to be dealt with by governments and the concerned public. Most of these process industries are oil refineries and oil processing companies whose wastewater contains multiple substances, contaminants, and other toxic materials that if they are not treated before they are disposed of, can cause an environmental disaster.

The Environmental Pollution Authority (EPA) of the United States enforces laws and regulations on proper wastewater management. They see to it that the right technology in wastewater treatment is applied in refineries. In other countries, they also have agencies implementing these similar regulations, although regulations and legislations vary from country to country. Refineries and establishments continue to violate some of these laws, causing an environmental problem.

Hydrocarbon components found in effluent water have to be separated and dissolved in order for the wastewater to be reused or disposed of properly, either for other purposes, such as agricultural or landscape irrigation. Hydrocarbons are harmful to humans, animals and plants.

One method of wastewater minimization is the water-pinch technology which was discovered in the 1990s but has since been modified by new methods. Much of the processes in water-pinch technology are still in effect today.

Another method of separating oil from water is through API separator. Pits that can hold thousands of gallons of water are constructed and the water is directed into several chambers, where the process is performed. A portion of this process is the cooling period where oil is also used to cool off the wastewater. Another method is through gravity, a natural process that involves flotation of the oil droplets, and performed in big tanks or containers. Centrifugal force is also applied to separate oil from water.

Biological removal reactors are effective in removing oil and grease from water. The process involves several stages until contaminants and other substances are removed from the water. One stage involves nitrification which completes the action of removing ammonia. Flotation separators are employed to separate waste from water. The separators use bubbles embedded in oil droplets. Examples of flotation separators are the DAF or IAF systems which use coagulants and flocculants to remove heavy oil and solid particles in the wastewater.

Refineries that use wastewater management and treatment throughout the world are cited in this paper. One example is Saudi Aramco, one of the largest oil companies in Saudi Arabia. The company uses desalination to supply drinking water to the big population of employees in their refinery. But desalination is too costly, about 6 Saudi riyals for every cubic meter of water. Therefore Saudi Aramco has turned to wastewater treatment. They can reuse wastewater in supplying commercial establishments and for landscape irrigation. Wastewater is a source of industrial water in Saudi Arabia, particularly in their refineries.

Another example of a refinery that has intensively used wastewater treatment and reuse is the Attock Refinery Limited in Pakistan. It has four crude mixes and distillation units used in treating wastewater. One important note is that in the beginning, the refinery was a violator of the Environmental Protection Act of 1997, Pakistan’s law on wastewater management and reuse. But ARL learned its lesson and is now one of great examples when it comes to wastewater management using innovative wastewater treatment and reuse. The technology controls pH, other substances, and creates a good processing technique on the effluent streams.

In some Pacific countries like the Philippines, treated wastewater coming from the refinery flows out to the mouth of Manila Bay. The refinery uses multiple-angle coalescing system, treating a big volume of wastewater before it is exited onto the bay. They use separator pits using DAF chambers where water is impounded for treatment, and then flowed out to the ocean. There’s no intention however of reuse in the wastewater because it can be noted here that the Philippines has several water dams for their major source of water.

The Shuaiba Industrial Area in Kuwait is a major source of wastewater. They have promoted reusable wastewater. Kuwait has less rainfall throughout the year so they are in dire need of water. The Shuaiba Area Authority is charged with the big challenge of converting wastewater into something useful. They have transformed wastewater and made it reusable for industrial and agricultural purposes. The Shuaiba generates up to 50,610 cubic meters/day of water. They are now using treated wastewater for landscape irrigation, industrial and sanitary uses.

On the other hand, the Duna Refinery in Europe uses wastewater treatment plant in their waste management, with the opening of their state-of-the-art air flotation facility. Europe has stringent measures when it comes to wastewater management. Treatment facilities and technology have to be continuously upgraded to meet the demands of European standards.

Conclusion/Recommendations

The world needs to recycle water, and the only option is to treat wastewater for reuse so that our streams and rivers would not be a dumpsite of contaminated wastewater. Wastewater is contaminated with chemicals of various kinds that can destroy the environment. It is time for some refineries and commercial establishments to employ measures to treat wastewater and find ways to be able to reuse it.

Wastewater is common in our process industries, refineries, and commercial establishments, which use a lot of water and discharge too much wastewater. Wastewater management in industries should be handled by expert engineers and managers. This is just like delivering a product to a customer. Quality water comes from good wastewater management.

There are many benefits in proper wastewater management and in reusing wastewater. First and foremost, some benefits can be derived for the environment. There is less water pollution, and the rivers and open seas can be free of pollutants. Wastewater can be reused in industries and commercial establishments. In areas where there is less rainfall, wastewater reuse is of paramount importance.

In Kuwait for example, wastewater management encountered by the Shuaiba Area Authority, has been resolved through constant checks and upgrading. The benefits derived from wastewater management are enormous. The same with Saudi Arabia, a Middle East country that depends much on sea desalination and wastewater reuse. Saudi Aramco, the large refinery in Saudi Arabia, has implemented wastewater management with utmost enthusiasm because of the many benefits derived from it. These countries regard water like it is the lifeblood of their refineries and countries. Adequate and proper wastewater management, applied with new tools in technology, can provide long life to their refineries.

We have also discussed in the literature the different methods of oil separators or the ways to separate oil from water. It is not for us to recommend what is the better technology because this really depends on the refinery complex. There are those that best apply to a particular situation.

For example, in the Shuaiba Industrial Complex, their method is a continuous analysis conducted on the boiler with its blowdown water that produced a neutralization process. Another example is that introduced by a refinery in Singapore. They use catalysts in oil separation. (Sun et al., 2001, p. 916)

One of the effective means of wastewater minimization is water pinch technology. This technology has been used as the model for other technologies in wastewater treatment and minimization. Through the years, the technology has been modified and applied or employed with some other technologies to make it more perfect in wastewater treatment. The principle in the water pinch analysis is to apply several contaminants to fight the already present contaminants in the water. The water pinch technology allows an analysis of the consumption of freshwater and generation.

Finally, Huchler (2000) recommends that to have successful water reuse, management should include creating a water balance, which involves recycling and segregating, and then final treatment.

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