Thursday, February 5, 2015

Overview of Glass Industry

Glass is one of the most versatile materials used not just in many industries but also in daily life.  Glass has many uses because of its transparency, high resistance to chemical attack, effectiveness as insulator, ability to contain a vacuum and many other properties. Glass is also one of the oldest materials in the world. Archaeologists have found evidence of man-made glass in Egypt which dates back to 6000BC. On the other hand, flat glass was mentioned as early as 290 A.D. (Shreve & Brink Jr., 1977)
Glassworks in the United States were founded in 1608. The first glass rolling process dates back to 1688 in France. Joseph Paxton's Crystal Palace at the Great Exhibition of 1851 marked the beginning of the discovery of glass as a building material. The revolutionary new building encouraged the use of glass in public, domestic and horticultural architecture. However, glass back then was very expensive because it was considered an art with closely guarded secret formulas and empirical processes of manufacturer based from rule of thumb and experience.  It was not until the beginning of the 19th century that glass has become relatively cheaper made possible by the invention of machine process that can mass produce glass. The invention of the first bottle machine in 1904 by Owens also marked the rapid developments of machine processes for glass production. In 1952, Sir Alastair Pilkington invented the float process that greatly reduced the laborious work of flat glass production. Before the development of float process, larger sheets of plate glass were made by casting a large puddle of glass on an iron surface, and then grinding and polishing both sides for smoothness and clarity - a very expensive process.
From 19th century onwards, scientists and engineers enter the field with increasing numbers and new products appear as a result of intensive research.  Today, glass making is a modern, hi-tech industry operating in a fiercely competitive global market employing all the tools of modern science and engineering in the production, control and development of its many products.

Nowadays, in general, commercial glass products fall into numerous classes according to composition:

1.     Fused Silica or vitreous silica. This class of glass is made from high-temperature pyrolysis of silicon tetrachloride. It has high chemical and thermal resistance because of its low expansion and a high softening point. This kind of glass is also extraordinary transparent to ultraviolet radiation.
2.     Alkali Silicates. They are the only two-component glasses of commercial importance. These are soluble glasses used in solutions. This glass type is widely used as an adhesive for paper in the manufacture of corrugated-paper boxes.
3.     Soda-lime glass. The soda-lime-silica represents by far the largest percentage of glass made today. It is used for windows, transparent fixtures, and containers of all kinds.
4.     Lead Glass. Commonly known as lead crystal, lead glass is used to make a wide variety of decorative glass object. It is made by using lead oxide instead of calcium oxide, and potassium oxide instead of all or most of the sodium oxide. It has also great importance in optical work because of its high index of refraction and high dispersion.
5.     Borosilicate Glass. It is made mainly of silica and boric oxide with smaller amounts of the alkalis (sodium and potassium oxides) and aluminum oxide. This type of glass has relatively low alkali content and consequently has excellent chemical durability and thermal shock resistance. As a result, it has many diversified applications.

6.     Special glasses. Other types of glasses not mentioned above fall under special glasses. It includes glass fibers used for reinforcement, optical glass used in scientific instruments, sealing glass used to protect metals, technical glass used in electronics and many more types used in emerging industries. 

Environmental Impacts of Different Industries - PVC Industry, Oil Refinery, Coating and Paint Industry

I. PVC Industry 

Environmental Impact of PVC

PVC is one of the most environmentally hazardous materials still used by the human population. The PVC industry has contributed a significant portion of the world’s load of persistent organic pollutants and endocrine-disrupting chemicals that are now present in the environment and the bodies of the human population (Thornton, 2005). PVCs are environmentally hazardous throughout their lifecycle: production, use, and disposal (Steingraber, 2004). By-products of PVC production are highly persistent, bioaccumulative, and toxic. The production of PVC products release harmful toxins in the atmosphere. Chlorine gas, used to manufacture ethylene dichloride, is highly toxic and is harmful to wildlife and humans. In addition, the production of chlorine gas has a much bigger impact than its emission to the atmosphere. To produce chlorine gas, the industry uses chlor-alkali facilities. And many manufacturers still use mercury as their catalyst. Chlor-alkali facilities that use mercury catalyst produce around ten percent of the total chlorine production but contribute greatly to annual atmospheric emissions of mercury. When elemental mercury from chlorine manufacturing plants is released to the atmosphere as a vapor, it can be carried long distances before returning back to earth. And when it does, methylating bacteria quickly convert the metal into an organic form, methylmercury, which is a powerful brain poison as well as a bioaccumulating, persistent pollutant. Methylmercury contaminates bodies of water and poisons neighboring communities as well. It is also quickly absorbed into the food chain, reaching its highest levels in fish and seafood (Mahaffey, 2004). Ethylene dichloride, the product from the reaction of ethylene and chlorine gas poses a negative impact too. It is a substance that is classified as a carcinogen and is notoriously capable of leaching into groundwater (Steingraber, 2004). Other by-products from PVC production with major concern are dioxins. Dioxins are very potent carcinogen and are global pollutants. They are now found in the tissues of whales in the deep oceans, polar bears in the high Arctic, and virtually every human being on earth (Thornton, 2005). Efforts to Minimize Environmental Impact of PVC The PVC industry has been under pressure from environmentalist as early as 1970’s. Measures have been used to reduce environmental impact since then. Across the world, governments, companies, and scientific organizations have recognized the hazards of PVC. In almost all European nations, certain uses of PVC have been eliminated for environmental reasons. The European PVC industry has also created a 10-year pan with fixed targets and deadlines to improve production process and products and to invest in technologies that are able to minimize emissions and wastes. Efforts have also been made to recycle PVC materials during manufacture to minimize waste. In Japan, 50% of end-of-life agricultural films are recycled into vinyl flooring materials. In the Philippines, there are no modern PVC recycling plants in operation yet. Several countries are now having big programs to reduce PVC use overall. Other communities have PVC avoidance policies being implemented. Dozens of green buildings have already been built with little or no PVC. Firms in a variety of industries have announced measures to reduce PVC consumption and are using or producing alternative materials in a variety of product sectors, including building materials (Thornton, 2005). Currently, there is now a large scale movement away from PVC products. In the field of research and development, a new PVC sustainability tool developed by a research group led by Professor Azapagic at the University of Manchester has been launched. It aims to help the producers of PVC products to reduce their environmental footprint. The sustainability software assesses the environmental and economic sustainability of PVC products and processes, enabling industry specialists to quickly estimate the costs, both to the environment and to their business. Moreover, PVC alternatives studies found HDPE and PEX to be good alternatives for some pipe and conduit applications. High Density Polyethylene (HDPE) is available for all pipe applications. Being non-chlorinated, requiring fewer additives, and having a much higher recycling rate, it is considered a more benign plastic. Cross-linked polyethylene (PEX) can also be an alternative because it has many characteristics similar to HDPE. Its molecules are crosslinked to improve its ability to handle higher temperatures (Calkins, 2006).

II. Oil Refining Industry

Environmental Impact of Oil Refinery Industry

The oil industry holds major potential hazards for the environment. It has impact at different levels: air, water and soil. The most widespread impact of the oil industry is pollution. Pollution is associated with all activities throughout the stages of oil manufacturing from drilling to refining. Wastewaters, gas emissions, solid waste and particulate emissions generated during oil processing are mainly responsible for pollution. Other environmental impacts aside from pollution include intensification of the greenhouse effect, acid rain, poorer water quality, groundwater contamination, biodiversity loss and destruction of ecosystems. Throughout oil processing, oil refiners are the major polluters consuming large amounts of water and consequently generating large volumes of wastewater. Hazardous gases are also generated and released into the atmosphere. Solid wastes that are difficult to treat and dispose are produced from oil refining processes. Thermal pollution is also generated due to the effluents with temperatures usually higher than recipient water bodies. Noise pollution is also possible from equipment doing plant operations (Mariano & Rovere, 2007). Petroleum refinery effluents that mainly come from refining crude oil and manufacturing fuels, lubricants and petrochemical intermediates are major source of water pollution. These effluents are composed of oil and grease along with many other toxic organic compounds. These pollutants pose serious hazards to humans and aquatic life (Saien & Nejati, 2007). Efforts to Minimize Environmental Impact Oil Refinery Industry In the Philippines, DAO 35 of 1990 regulates industrial and other effluents discharged into bodies of water so that they do not contain toxic substances in levels greater than standards indicated. Furthermore, the implementation of the national Water Code of the Philippines (P.D. 1067) prohibits the discharge of effluents to bodies of water that have low assimilative capacity. It revokes or suspends the permit of a company who violates effluent or water quality standards as determined by the National Pollution Control Commission. These regulations together with the measures provided by the Philippine Clean Air Act require oil refineries to have treatment systems for their wastewater and gaseous effluents. In the field of research, there have been developments in technologies used in treating emissions from the refinery process. Heterogeneous photocatalytic degradation is a well researched and established advanced oxidation process (AOP) used for wastewater treatment. Radiated processes, specifically, Fenton and photo-Fenton advanced oxidation process have already been tested and have been showed to be most effective to remove the organic matter found in the sour water produced from the refinery processes (Coelho, et.al.,2006). The difficulty in treating contaminants present in the wastewater is addressed by inculcating and introducing genetically modified organisms into biological treatment systems. A novel investigation of an activated sludge system was conducted by Shokrollahzadeh et al. (2008) with the aim of addressing the system’s inability to degrade a wide range of recalcitrant contaminants. An important result of the research was the successful isolation of aerobic bacterial species having excellent diverse catabolic activity that could be used in most types of bioremediation. On the other hand, a study made by Elcock, et.al., (2000) offers alternative environmental regulatory approaches for existing petroleum refineries to be used in the future. These alternative approaches provide for new technology development and use, and allow flexibility in the means for meeting environmental goals. The goal-based approach requires less change to the current system and relies less on the findings of forthcoming scientific and technological research. The risk-based approach requires the development, testing, and acceptance of modeling systems and data on parameters such as pollutant toxicities, exposure routes, dose–response relationships, and cumulative effects. Under a grant from the Environmental Technology Initiative (ETI), these two alternative environmental regulatory approaches are developed for today’s petroleum refineries to use in the future. These approaches are designed to expand the use of innovative technologies, encourage pollution prevention, demonstrate environmental responsibility, and maintain refinery economic performance.

III. Coating Industry: Paint 

Environmental Impact of Paint

The environmental impact from the paint industry is associated with wastewater generation, air emission and solid waste contaminated with toxic metals. Wastewater from paint industry can be highly toxic to the environment. There are a number of waste streams, including acid and metal sulfates from the manufacturing process, each of which carries an environmental impact. The paint industry is one of the major contributors for polluting the soil and water resources with poisonous substances such as lead, chromium and cadmium. It harms fish, wildlife, and contaminates the food chain if wastewater is poured down a storm drain. It can disrupt microbes and causes sewage treatment to be less effective. It can also pollute groundwater if dumped onto the ground. Many studies have also shown the health risks due to toxic metal-containing paint at homes, work place and other industrial units using paint. For example lead poisoning may be one of the most prevalent diseases of environmental and occupational origin due to the use of lead in paints in buildings (Gondal & B, 2006). The paint industry uses about 300 different types of raw materials for production of different kinds and qualities of paints. About 15% of raw materials of this industry are petroleum-based. The major raw materials of paint industry are pigments, zinc oxide, titanium oxide, lithopone, mineral, turpentine, resins, vegetable resins and gums. The main environmental impacts associated with paint come from the production process of the components, rather than manufacturing of the final paint products ready for packaging and selling. Another reason behind that is because raw materials for production of components are derived from scarce resources. By far the greatest environmental impact in the manufacturing of paint is the manufacture of Titanium Dioxide (TiO2) a pigment so fundamental to the performance of any paint, that it is difficult to avoid - even amongst 'eco' paints. The manufacturing produces emissions including CO2, N2O, SO2, NOx CH4 and VOCs. VOCs from the process react with nitrogen oxides and carbon monoxide to produce ozone which is a pollutant in the troposphere and a constituent of smog (Greenspec, 2013). Efforts to Minimize Environmental Impact of Paint As early as the 19th century, industrial users of paint already faced strict environmental regulation on their operations because of the large volumes of solvents released in the surface coating process. Paint manufacturers had already started then providing innovative solutions to meet the demands of the regulations. In the U.S., users of industrial coatings began to be regulated with the passage of several state regulations in the 1960s and 1970s as well as the Clean Air Act Amendments of 1977. In accordance to it, the EPA provided Control Technique Guidelines (CTG) and New Source Performance Standards (NSPS) as aids for the state regulators and permit writers. Typically, these documents offered practical limits on the VOC content of coatings. If manufacturers chose not to change coatings, then they could comply by adding control equipment to their operations. The U.S. led the implementation of regulations for coating application. But then in the late 1980s, Germany, the Netherlands, and the U.K. began adopting similar regulations (Bonifant, 1994). The Volatile Organic Compounds in Paints, Varnishes and Vehicle Refinishing Products Regulations (VOC 2010 legislation) came into effect in 2010. The aim of the legislation has been to enforce cuts in VOC emissions on top of existing standards established in 2007. In response to stricter environmental standards, there are now safer alternatives to conventional paints. There are more sustainable products available, such as low-voc acrylics or natural paints which apart from being better for the environment, produce little or no fumes when painting. Natural paints are made using naturally occurring ingredients, and therefore do not require high levels of processing. Many of the ingredients are now made from renewable resources, such as linseed oil, and citrus oil. Natural paints use plant-derived solvents and binders instead of synthetic ones so that VOC levels of between 0-1 percent are now possible. Natural paints are generally well-tolerated by humans and the environment (Greenpainters, 2007). Moreover, use of water-based or latex paint which is more environment-friendly and easier to apply and clean up is also available in the market. Research is still being done for water-based paint to achieve the superior quality that solvent-based paint gives while still meeting environmental regulations. Advances in paint research also produce important tools in evaluating environmental impact of paints and help in identifying the causes of negative environmental impact. For example, the GM Research and Development Center in the US pushed through the development of environmental impact life cycle analysis (LCA) of the manufacturing of different kinds of paint. Life cycle assessment tools contribute quantitative results to the decision process, and are very useful for the evaluation of the environmental emissions associated with the manufacturing, use and end of life of materials and processes. This kind of analysis can identify the sources that contribute the most to adverse environmental impact and can provide necessary information that allows the design and manufacturing of alternatives. Papasavva, et al., used LCA to evaluate the environmental impact of different automotive paints. Their study showed that the overall environmental performance for production of the polyester primer (solvent borne and powder) is superior compare to the acrylic powder.

References 

Bonifant, B. (1994). Competitive Implications of Environmental Regulations in the Paint and Coating Industry. Management Institute for Environment and Business , 2-3.

Calkins, M. (2006, March). To PVC or Not to PVC. Retrieved March 2013, from Healthy Building Network: http://www.healthybuilding.net/pvc/calkins_asla.html Coelho, A.,

Castro, A. V., Dezotti, M., & Jr, G. S. (2006). Treatment of petroleum refinery sourwater by advanced oxidation processes. Journal of Hazardous Chemicals , 184.

Elcock, D., Gasper, J., Moses, D., Emerson, D., & Arguero, R. (2000). Alternative future environmental regulatory approaches for petroleum refineries. Environmental Science & Policy , 1,10.

Gondal, M., & B, T. H. (2006). Determination of poisonous metals in wastewater collected from paint. Science Direct , 8.

Greenpainters. (2007, May). Paint industry impacts environment: Greenpainters. Retrieved March 23, 2013, from Infolink: http://www.infolink.com.au/c/GreenPainters/Paint-industryimpacts-environment-Greenpainters-n747418

Greenspec. (2013). Materials,Manufacturing, Impact of Paints. Retrieved march 23, 2013, from greenspec: http://www.greenspec.co.uk/paint.php

Mahaffey, K. (2004). Methylmercury: Epidemiological Update. Report presented at the Fish Forum, San Diego (U.S. EPA) , 21.

Mariano, J. B., & Rovere, E. L. (2007). Environmental Impacts of the Oil Industry. Petroleum Engineering , 1-3. McKay, R. M., & Bounk, M. J. (1982).

Iowa Geological and Water Survey. Retrieved March 2013, from Underground Limestone Mining: http://www.igsb.uiowa.edu/browse/undrlime/undrlime.htm

Papasavva, S., Kia, S., Claya, J., & Gunther, R. (2000). Characterization of automotive paints: an environmental. Science Direct , 14.

Saien, J., & Nejati, H. (2007). Enhanced photocatalytic degradation of pollutants in petroleum refinery wastewater under mild conditions. Journal of Hazardous Materials , 148; 491–495.

Shokrollahzadeh, S., F.Azizmohseni, & Golmohammad, F. (2008). Biodegradation potential and bacterial diversity of a petrochemical wastewater treatment plant in Iran. Bioresource Technology , 99,6127–6133.

Steingraber, S. (2004). Update on the Environmental Health Impacts of Polyvinyl Chloride (PVC) as a Building Material:Evidence from 2000-2004. A commentary for the U.S. Green Building Council , 2-24.

Thornton, J. (2005). Environmental Impacts of Polyvinyl Chloride (PVC) Building Materials. A briefing paper for the Healthy Building Network , 2-3.