VATIS Update Waste Management . Mar-Apr 2003

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Waste Management Mar-Apr 2003

ISSN: 0971-5665

VATIS Update Waste Management is published 4 times a year to keep the readers up to date of most of the relevant and latest technological developments and events in the field of Waste Management. The Update is tailored to policy-makers, industries and technology transfer intermediaries.

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Disclosure of pollution information mandatory in Europe

An international treaty under which companies are required to publicly disclose information regarding their output of pollutants is being framed, under the United Nations Economic Commission for Europe (UNECE), in the form of a legally binding pact to the Aarhus Convention. As per the new protocol, companies would be compelled to report annually on their releases (into the environment) and transfers (to other companies) of a few listed pollutants. The data will then be placed on a public register, known as a pollutant release and transfer register or PRTR. Some key features of PRTR include:
l Each party to the protocol will be required to establish a publicly accessible and user-friendly PRTR, based on a compulsory scheme of annual reporting;
l The register will cover information on 86 pollutants considered to pose the most significant threats to environment or health, including greenhouse gases, acid rain pollutants, heavy metals and cancer-causing chemicals such as dioxins;
l Reporting will be required for a wide range of activities, including refineries, thermal power stations, the chemical and mining industries, waste incinerators, wood and paper production and processing, and intensive agriculture and aquaculture among others, where these activities are carried out on a significant scale;
l While the primary target is large point sources of pollution, a framework is also provided for reporting on pollution from diffused sources such as traffic, agriculture, and small and medium-sized enterprises;
l Some of the reported information may be kept classified, e.g. where disclosure could affect commercial confidentiality, national defence or public security, but such exemptions should be interpreted in a restrictive way, taking into account the public interest served by disclosure; and
l Information should be provided and made available on the register on a facility-specific basis.

Contact: Mr. Jeremy Wates, Secretary to the Aarhus Convention, UNECE Environment and Human Settlements Division, Switzerland. Tel: +41 (022) 9172 384; Fax: +41 (022) 9070 107; E-mail: ; Website: ; Website: 

Tackling e-wastes in Asia

Under the guardianship of the Basel Convention on Transboundary Movement of Hazardous Wastes and their Disposal, officials from eight Asian governments would together seek solutions to the growing deluge of electrical and electronic wastes or e-wastes. The meeting would also consider producing authoritative data on e-waste streams and evaluate existing technical practices. Environmentally healthy management of electronic wastes is an important element of the Strategic Plan now being developed by member governments of the Basel Convention. Representatives from China, Malaysia, India, the Philippines, Singapore, Sri Lanka, Thailand and Viet Nam participated in this event.

Asian nations are considered to be the main importers of e-wastes produced around the world. Importing countries earn significant revenue by refurbishing used PCs and through disassembling obsolete PCs, circuit boards and monitors, and then recovering the gold, copper and other precious metals. End-of-life PCs as well as printers and other related equipment are made using highly sophisticated mixtures of plastics, metals and other materials. They often contain hazardous substances like cadmium, mercury and lead. E-waste workers face dangerous working conditions where health, safety and environmental criteria are compromised.

Contact: Mr. M. Williams, Geneva, Switzerland. Tel: +41 (22) 9178 242/244/196;
E-mail:   ; Or Mr. Eric Falt, Nairobi, Kenya. Tel: +254 (2) 623 292; E-mail: ; Or UNEP DTIE Energy and Ozonaction Branch, Tour Mirabeau, 39-43 quai Andre Citroen, Paris 75739, Cedex 15, France. Tel: +33 (1) 4437 1450; Fax: +33 (1) 4437 1474.

Garbage from West poisoning water and soil in East

Asian countries have increasingly become dumping grounds for vast quantities of obsolete electronics shipped in from the United States, Europe and Japan. Even as entire communities, inclusive of children, earn their livelihoods by scavenging metals, glass and plastic from the dumps, the technological garbage is poisoning water and soil, raising serious health concerns.

In the United States alone, where over 40 million computers became old-fashioned in 2001 according to a National Safety Council report, about 80 per cent of rubbish collected by recyclers are sold to intermediaries and shipped to Asia. The people at the receiving end of e-wastes are bearing the real costs. In several towns along Chinas coast, as well as in India and Pakistan, adults and children work for about US$1.20 a day in unregulated and unsafe conditions. Guiyu is one such town on Chinas south-eastern coast. The workers acknowledge cuts on their fingers, infections that do not heal. Stubborn, hacking coughs testify to the poorly ventilated places in which they breathe noxious vapours. As rivers and soils absorb a mounting influx of carcinogens and other toxic compounds, people suffer from high incidences of birth defects, infant mortality, tuberculosis and blood diseases, as well as particularly severe respiratory problems, according to reports by Beijing Youth newspaper and the state-controlled Guangdong Radio.


Eco-design helps comply EU legislation

In Japan, several companies report to have made significant strides in eco-design, recycling and lead-free soldering technologies, steps that could help businesses conform with tighter European Union (EU) rules on products and wastes. According to a report by the Centre for Sustainable Design (CFSD) in the United Kingdom, a US$220 billion technology programme, along with new laws on recycling and green purchasing is spurring new recyclable products. Under the new laws, at least 50 per cent of all home appliances must be recycled, with high targets being phased in. According to CFSD, businesses are redesigning products, making them smaller and easier to dismantle with reusable/recyclable parts. At the waste end, discarded products are assessed for their dismantlability and recyclability. New materials are also being launched, such as plastic and wood hybrid, while several recycled materials are finding new uses, e.g. recycled plastic in fishing floats.

Japan aims to create a closed loop consumer society where products and materials are endlessly recycled (zero wastes for landfill sites) while consumers keep buying. Electrical giant Matsushita recently opened Matsushita Eco Technology Centre to show the public how it plans to recycle 400,000 appliances a year. Take back schemes have also been successful, prompted by Shame on you advertising campaigns against fly-tipping. Non-compliance with the new legislations would invite fines of US$2,350 each or up to US$785,000 for a company. Firms will also have to be careful of Life Cycle Assessment (LCA), used indiscriminately in Japan to work out the environmental impact of products. An LCA could become redundant if a product is slightly modified. Additionally, since the assessment is not standardized, firms could come up with different answers for the same product. Overconfidence in LCAs can also lead firms to rely too heavily on unverified data coming from their suppliers.


Japanese biomass recycling programme

Japan plans to launch an ambitious programme aimed at recycling leftover foodstuff, livestock manure and scrap wood as biomass energy to fuel cars, ships and power plants. According to a draft of the Biomass Nippon strategy, the government will designate some 500 communities as model areas for intensively implementing projects to utilize biomass energy. This initiative is expected to contribute to fighting global warming by reducing the use of fossil fuels, thereby decreasing the amount of carbon dioxide (CO2) released into the atmosphere. By 31 March the government will launch a study to assess the quality of diesel fuel made from used rapeseed oil and other food waste, and test the fuel in cars and ships. Biomass Nippon strategy also includes constructing biomass power plants to be fuelled by scrap wood and methane gas originating from animal droppings, promoting usage of biomass products made from manure, and utilizing ethanol obtained from plants as automobile fuel.


Bonds fund Chinas sewage works

More than US$3.6 billion has been invested by China in urban wastewater treatment since 1998, a total of 317 projects across the country, using cash raised by selling treasury bonds. Another US$72.5 million was used to construct 22 wastewater recycling projects, which boast a recycled wastewater supply capacity of 1.5 million m3/d overall. Additional money will be raised from treasury bonds and used to fund wastewater treatment projects in the future.

Water pollution situation is pressing in China. According to the Ministry of Construction, 63 per cent of rivers and over 90 per cent of urban underground water is polluted. The annual discharge of wastewater is around 32.8 billion m3 and presently 36.4 per cent of wastewater is treated. There are now 452 treatment plants across the country, with a total capacity of 31 million m3/d. The 10th five-year plan (2001-05) has set a target to treat 45 per cent of wastewater.


Recycling wastes

The Malaysian government and Alam Flora plan to jointly recycle garbage, expected to reach over 7,000,000 t/y by 2023. Mobile recycling units would be sent to residential areas, commercial centres and industrial sites to collect recyclable wastes, weigh and make payments according to the market rate. Alam Flora has set a recycling target of 22 per cent, from the current 3 per cent, for areas under its jurisdiction Pahang,Selangor, Putrajaya, Kuala Lumpur and later, Kelantan and Terengganu.Recyclable goods include books, newspapers, magazines, aluminium cans, carton boxes, mixed papers, metal tin and cans, glass bottles and jars, plastic bottles and commingled plastics. At present, Alam Flora is handling 1,000,000 t/y of waste in Kuala Lumpur and 2,000,000 t/y in Selangor and Pahang.

Tax on scrap metal exports proposed

In the Philippines, local steel-making and metal casting industries want the government to tax exporters of scrap metal if a ban on exports is not feasible. The House of Representatives committee of trade and industry has refused to recommend a ban on the export of scrap metals. The Philippine Metal casting Association Inc. (PMAI), an association of about 200 metal casting companies, states that scrap metal is the main source of raw material for local steel and metal casting industries. Apart from PMAI, Philippine Steel-makers Association is opposing scrap metal exports. Cathay Pacific Steel Corp. also argues that billet making and metal casting sectors will run short of raw material. However, studies reveal that there is no shortage of scrap metals supply in the local market since the country generates about 600,000 t of scrap metals, more than double the actual maximum use of 250,000 t.


Mandatory recycling of plastic containers

In the Republic of Korea, the Ministry of Environment intends to enforce new rules that compel recycling of plastic containers, after reviewing its existing laws. At present, only plastic bottles and Styrofoam boxes are being recycled. From next year, instant noodle containers and Styrofoam plates will be collected separately and recycled. The new legislation is expected to come into effect in 2004.


Penalty for illegal trafficking of foreign garbage

A draft amendment of the Criminal Law in China is aimed at tightening punitive measures against illegal trafficking of garbage of foreign origin. This move is intended to make it easier for judicial authorities to impose penalties on such activities. According to the draft amendment, those who smuggle solid, liquid or gaseous wastes into the country could face a prison sentence up to five years and a monetary fine, or a single financial penalty. Importers of garbage under the guise of raw materials would face similar punishments. As per the current Criminal Law, fines are levied based on the amount of tax evaded.


Fly-ash utilization mandatory in India

In India, the amended Fly-ash Rules scheduled to be shortly notified by the Ministry of Environment and Forests stipulate the use of fly-ash in construction, laying of roads, reclamation of low-lying areas, etc. The earlier Fly-ash Rules notified in September 1999 are being revised to make it compulsory for all agencies that are engaged in construction of buildings within a radius of 100 km from coal or lignite-based thermal power plants to use fly-ash or blocks or tiles. Beginning with a minimum of 25 per cent of fly-ash products, the new rules require 100 per cent use of fly-ash products ultimately, as per the specified schedule. This applies to all construction agencies such as housing boards and private builders of apartments, cottages, resorts, hotels, etc.

The amendments also ban construction of roads or flyover embankments contradicting guidelines issued by the Indian Road Congress within a radius of 100 km of thermal power facilities. Reclamation of low-lying areas within a radius of 100 km will have to be done only with pond ash. All agencies undertaking construction of either roads or flyover bridges, including the Ministry of Road Transport and Highways, National Highway Authority of India, Central Public Works Departments, State Public Works Departments and others are required to make necessary guidelines/specifications for road or flyover embankments to enable the use of fly-ash and its products. Some of the agencies working towards fly-ash management and disposal include National Thermal Power Corp., AEC, IITs, Central Scientific and Industrial Research Laboratories, etc.
Chemical Weekly,14 January 2003

War on plastics

Taiwan intends to prohibit the use of disposable plastic bags, bowls and other utensils. The ban will apply to supermarkets, fast food chains, department stores, restaurants and convenience stores. Thousands of volunteers are promoting the government campaign, which aims to reduce landfill waste and street litter. Stores keep reminding consumers to bring their own shopping bags or pay extra for paper bags. Disposable bowls and other plastic ware have been popular as they are cheap and sanitary. Government officials estimate that plastic utensils and bags account for 54,545 t/y of waste.



New equipment

Belgium-based Magnetic Devices Engineering (MDE) offers a range of magnetic separation equipment for use in domestic and industrial waste treatment, processing as well as recycling facilities. MDEs first system incorporates a rectangular suspended magnetic separator that is mounted above a conveyor belt, an oscillating conveyor or a vibrating feeder. This tripolar magnetic separator, with permanent magnets or an electromagnet, develops a deep, high-gradient magnetic field that ensures optimum extraction of ferrous particles contained in the material transported. Some application areas where this unit is useful include:
l Protection of industrial production equipment such as conveyor belts, crushers, grinders, screens/sieves from damages caused by extraction of stray iron;
l Recovery and enrichment of blast furnace slag, steelworks clinker and incineration plant cinders and ash by extraction of ferrous materials;
l Purification of noble materials by extraction of dangerous or undesirable ferrous particles like foodstuffs, foundry sand, chemical products, etc.; and
l Recovery of valuable tools and of machine parts accidentally missing.
The company also offers magnetic pulleys, with neodymium-iron-boron or strontium-ferrite type permanent magnets, which produce a powerful magnetic flux penetrating the thickness of the material transported on the conveyor. The magnetic circuit, formed from radial poles with alternating polarities all along the pulley generator, creates a high-gradient magnetic flux, a key factor in the effective removal of ferrous particles. The dry-drum magnetic separator is a separation and purification unit capable of handling high throughputs of large grain size materials. It can be used for a variety of purposes, including enrichment of steelworks clinker, treatment of domestic waste, recovery of scrap iron, purification of blast furnace slag, recycling units, mining and quarrying, cement works and the glass industry.
The Overband magnetic separator is mounted above a conveyor belt. High-gradient magnetic flux, concentrated in the fluid vein of the product to be purified, extracts undesirable ferrous particles and discharges the same from the conveyor into a dedicated spout. 

Contact: Magnetic Devices Engineering, Chaussee de 
Gramptinne 76, B 5340 Gesves,Belgium. Tel: +32 (083) 677 650; Fax: +32 (083) 678 103; 

Waste stabilization technologies

The United Kingdom-based Air Products Plc. offers a volatile organic compound (VOC) recovery unit that uses liquid nitrogen to pre-chill VOCs to temperatures as low as 120C. The 15 m2 CryoCondap system can handle up to 450 g/m3 of VOCs such as acetone, ethanol and methylene chloride, with overall emission level of 150 mg/m3. This single system fulfils the most stringent emission guidelines. A key factor that enables low operating costs for this unit is the ability to reuse nitrogen. Nitrogen created in the condensation process can be used to purge and blanket pipeworks and tanks.

Contact: Air Products Plc., Hersham Place, Molesey Road, Walton-on-Thames, Surrey KT12 4RZ, the United Kingdom. Tel: +44 (800) 3890 202; Fax: +44 (1270) 259 506;


Tracking pollution using electricity

A cheaper and easier way to unearth toxins buried in fields, rivers, ditches and woods has been developed at the University of Rhode Island, the United States. By depending on a simple electric current, builders can detect pollutants, reaping significant financial benefits. In this process, two metal spikes connected to an electricity source are driven into the ground. After the spikes are buried, voltage between the spikes can be measured to determine if an underground water source or soil is contaminated. As organic carcinogens such as benzene, xylene and phenol do not conduct electricity, resistance to the current increases significantly in areas where an aquifer is polluted. The system is being tested under a US$55,000 EPA grant.



Plasma-based systems

Plasma method offered by Plasma Environmental Technologies (PET) Inc., based in the United States, is an electrothermal, non-incineration process that produces an intense field of radiant energy, at a temperature of several thousand degrees, that breaks apart molecular bonds of the liquid, gaseous and solid compounds of toxic and non-hazardous wastes. The molecules are separated into their elemental atomic 
components and then reformed into non-hazardous by-products or converted into commodities exhibiting commercial potential. It is feasible to produce known, desired and safe outputs such as nitrogen, carbon dioxide, steam and fuel gas by monitoring and controlling chemical reactions within the plasma process.
PETs technology operates without a conventional fuel and there is no flame or by-products. It generates minimal off-gas volume and does not create ash, often a toxic by-product of combustion-based thermal processes. Some advantages of this process include:
l The destruction and removal efficiencies (DREs) of hazardous substances is 99.99995-99.999998 per cent;
l Dioxin and furan emissions are well below regulations;
l Low NOx emissions;
l Minimal handling and preparation of feed material;
l High throughputs; and
l Low capital, operating and maintenance costs.

Contact: Plasma Environmental Technologies Inc., 4145, North Service Road, Suite 200, Burlington, ON L7L 6A3, Canada. Tel: +1 (905) 3329 693; Fax: +1 (905) 3329 792; Website: 

Remediating wastes

In the United States, PEAT International provides proprietary, eco-friendly waste remediation methods to convert toxic, infectious, military, industrial and municipal wastes into synthetic gas and other useful products. Plasma Thermal Destruction and Recovery (PTDR) technology is claimed to be the first commercially viable solution for waste remediation, utilizing thermal plasma technology. This patented process uses energy from plasma, in the form of a plasma arc torch, to thermally convert inorganic and organic waste into gas through a process called pyrolysis or controlled gasification. Constant high operating temperatures ensure destruction of all complex organic compounds, and proprietary process control limits the possibility of reformation of complex pollutants. PTDR system consists of the seven subsystems mentioned below:
l Waste feed system;
l Processing chamber (furnace);
l Plasma heating system;
l Solid residue removal and handling system;
l Gas clean-up system;
l Product gas flare; and
l Supervisory control and data 
acquisition system.
The processing chamber is heated to the desired temperature (up to 6,000C) before the waste stream is fed continuously by the feed system. Organic materials rapidly dissociate into elemental constituents, mainly hydrogen, carbon, oxygen and frequently a halogen. Pyrolysis product gas (syngas) that is formed from the organic waste is piped to a quench and gas-scrubbing system where the acid gas is neutralized and entrained particulate is removed. The resulting clean fuel gas, i.e. carbon monoxide and hydrogen, could be utilized as a fuel for steam or power generation or the hydrogen can be extracted as a clean fuel. 

Contact: PEAT International, 555, Skokie 
Blvd., Northbrook, Illinois 60062, the United States. Tel: +1 (847) 5598 567; Fax: +1 (847) 2913 704.Website: 

Bio-treatment of municipal wastes

In India, the Pune Municipal Corp. is employing a liquid culture, developed in Japan at the University of the Ryukyus, to treat solid wastes. The effective micro-organisms or EM concoction contains 80 strains of beneficial and naturally occurring micro-organisms, with predominant populations of lactobacillus and actinomycetes bacteria. EM leads to fermentative decomposition, a odour-free method to degrade wastes.
In this process, 1 l of EM solution is mixed with 3 l of molasses and 100 l of chlorine-free water. This solution is kept in an airtight drum for seven days, during which the microbes, under anaerobic conditions, multiply 100 times. After this, the solution is further diluted with water and then sprayed on the garbage. Bacteria decompose the waste in approximately 45 days. The Pune Municipal Corp. is employing this technology to treat 700 t of organic waste, which costs about US$31 per day. EM has been certified by the University of Pune as an eco-friendly product.

Down to Earth,15 January 2003


New lint cleaner reduces cotton waste

In the United States, a researcher at the Agricultural Research Service has developed a device that reduces the amount of usable cotton typically lost in gins and increases the weight of a single cotton bale after ginning by around 4.5 kg. After the lint is separated from seed, lint cleaners remove foreign matter, moisture and other contaminants that lower the value of the crop. The lint-cleaning stage usually results in losses of about 9 kg per 225 kg cotton bale. The new lint cleaner incorporates an additional saw cylinder to reprocess fibre that is normally ejected with the waste. This process prevents most good fibre from being ejected by the lint cleaner along with leaf particles, sticks, stems, seed coat fragments, grass and bark that must be removed. The novel device can also be used to separate fibres from alternative crops such as kenaf and flax, which are used in the production of paper and linen.


Converting agro-wastes into ethanol

EcoFuels Corp., the United States, has developed HYAD processing unit that converts biogas obtained from agro-wastes into fuel-grade E85 ethanol, EPA registered as ethanol plus and trademarked Ecalene. The HYAD process employs ASBR technology to achieve digestion efficiencies higher than other methods. Physically, each digester is sized to accommodate waste at the confined animal feeding operation (CAFO). The tank is covered with a dome for collecting and storing biogas. Each digester is equipped with an agitator to mix the contents.

Operation of the digester involves a series of steps repeated all through the day. At the start of each cycle, a combined volume of manure and substrate are slowly added to the digester tank. Water and solids overflowing the reactor is pumped to a lagoon. Enriched fermented broth is stirred gently inside the digester. Fermentation converts a portion of the organic material into biogas that rises to the surface of the tank and is collected by a header unit, which is connected to the alcohol process unit. In the final step the digesters contents are allowed to settle, which causes solids in the topmost layer within the reactor to drop down and result in a layer containing 1-2 per cent solids.

Ecalene process yields various higher chain alcohol that are predominantly straight-chain terminal alcohol in the C2-C5 carbon range. It is keyed to the development of a rugged selective catalyst, which can be used alone or in combination with other catalysts. Since a high conversion rate of synthesis gas is feasible at relatively low temperature and pressure, the need for an expensive oxygen plant does not arise. Extensive trials of the catalyst has shown no significant deterioration of activity or change in selectivity for the alcohol. The catalyst used is highly active and converts all the methane produced by the HYAD facility into fuel-grade ethanol. 

Contact: EcoFuels Corp., 1710, Douglas Dr. North, Suite 100, Golden Valley, Minnesota 55422, the United States. Tel: +1 (763) 5820 398; Fax: +1 (763) 8520 407;

Fowl manure to benefit environment

In the United States, scientists at the Agricultural Research Service have found a way to convert some types of animal dung into a material that can be used to help keep the environment clean. Ms. Isabel Lima reports that animal waste could be transformed into activated carbons, which soak up unwanted pollutants, and used for environmental remediation. Poultry litter, when pelletized and activated under specific conditions, becomes a highly porous stuff with a large surface area. Tests have shown that these carbons perform well in adsorbing copper and could be utilized as a wastewater filter for metal ions. Their adsorption rate also make them more cost-effective than those currently available.

At present, animal waste is valued between US$3 to US$10 per tonne and most of it is used as fertilizer. However, a build-up of nutrients namely nitrogen, phosphorus and potassium could occur, especially if applied repeatedly over the same area, leading to non-point source pollution run-off into streams and rivers as well as nitrogen leaching into shallow groundwater. This drawback has compelled a few states to introduce legislation limiting such applications.


Fuel briquettes from agro-waste

Appropriate Rural Technology Institute, India, has devised a technique to transform waste sugar cane biomass into agro-wealth. Post-harvest waste mostly comprises tough, unusable leaves that can now be converted into fuel-efficient, eco-friendly briquettes to supplement the income of farmers. The new process uses a specially designed kiln in which sugar cane leaves are deposited in different barrels. The kiln is heated until the leaves are burnt and this charred mass is mixed with binders and extruded into briquettes, which could be used as charcoal. A one-time investment of about US$400 ensures that a farmer earns around US$1,500/y.

INSTEP, Issue 3, June 2002


Plastic nuggets aid waste disposal

In the United States, Mr. James W. Garthe has developed a process that helps farmers deal with the disposal of agricultural and domestic plastics by generating combustible, energy-efficient plastic nuggets. In this process, mulch films, greenhouse films, and pots, flats and silage wraps are converted into plastic nuggets that can be burned with coal in coal-fired boilers, refuse-derived fuel burners and even cement kilns. Since the new technique does not melt the plastic, all types of plastics can be mixed. Only the outer portion of the nugget is fused to form a melt jacket that contains compressed plastic waste. According to the researcher, calculations show that only about 1/85th of the energy released when the plastic nuggets burn is used to create the nugget.


Slow shredders to process plastics

Rapid Granulator, Sweden, offers 
RS1000 and RS1400 shredders as a practical solution to recycle large lumps of melted plastics. Used in conjunction with Rapids 35 or new 45 series granulators, these enable virtually any type of plastic lump to be reduced to high-quality re-grind. The shredders feature a slow revolving rotor that reduces the risk of lumps jumping out of the shredder. The rotor is fitted with one or two rows of knives consisting of 27 and 54 individual knives, respectively. Lumps of up to 40 kg in weight can be fed into the shredder at a maximum throughput of 500-700 kg/h. A ram pushes the lumps against shredder knives, holding them in place while they are reduced and also preventing bridging of lumps in the feed hopper. This enables multiple lumps to be fed into the shredder simultaneously. Any overfeed is managed by using the reverse function of the rotor.

The PLC-controlled shredders have preset modes for different materials. They have an energy-saving relay that turns off the shredder whenever it is running idle for more than five minutes. Shredded particles pass through a screen, which can be set at 25 to 40 mm depending on the application. They then fall on to the conveyor, equipped with an optional metal detector, for transportation into a granulator hopper for final re-grinding.

Contact: Rapid Granulator AB, SE-330 10 Bredaryd, Sweden. Tel: +46 (370) 86500; Fax: +46 (370) 80251;

Sugar makes plastic biodegradable

In India, researchers at the National Chemical Laboratory report to have laced plastics with sugar to make them palatable to soil bacteria. The tweaked plastics include polyethylene, polypropylene and polystyrene. The team mixed styrene subunits of polystyrene with small amounts of another substance that provides a chemical hook for pieces of glucose or sucrose. They then added sugars to the styrene chains, like pendants on a necklace. By weight, less than three per cent of the final polymer is sugar, so the material is more or less the same. However, bacteria such as Pseudomonas and Bacillus break open the chains when they feast on the sugary snacks, kicking off decay.


Recycling of heavily printed films

Erema Engineering Recycling Maschinen und Anlagen Ges.m.b.H in Austria has developed a system to recycle very heavily printed materials like PET bottle labels. A frequent problem faced while recycling such materials is print colour deposition on the extruder screw in the area of the melting zone. In addition to this, non-homogenized colour agglomerates often clog the melt filters during recycling. As such, recycling heavily printed film has been impeded by very short screen change and screw cleaning intervals or notably lower throughput, making printed waste film available at a low cost even in the form of clean production waste.

Some extruder screw systems are better suited than others to recycle printed films. Erema has thoroughly analysed such screw systems and tested extruders with varying outputs. Following a differentiated trend analysis with varying parameters, which were implemented in targeted screw geometry changes, very positive results were achieved. Eremas system can be operated in virtually all cases for weeks without losses in throughput.

Contact: Erema Engineering Recycling Maschinen und Anlagen Ges.m.b.H, Unterfeldstrae 3, POB 38, A 4052 Ansfelden/Linz, Austria. Tel: +43 (732) 3190-0; Fax: +43 (732) 3190-23; E-mail:
Popular Plastics and Packaging, December 2002


Vacuum distillation evaporator

Severn Trent Services, the United States, offers Samso WasteSaver evaporator unit to evaporate wastewater, helping achieve substantial economic and environmental benefits. A unit installed at Roll Coater has resulted in 90 per cent lower wastewater treatment costs and 90 per cent reduction in waste volumes to be treated.
Coil coating is a continuous as well as highly automated technique for coating metal before fabrication. The coated sheets of metal are used to manufacture construction materials, appliances, automotive parts, office furniture, containers and other products. Before the metal is coated, it should be cleaned and wastewater generated during this process must be disposed. Severn Trents evaporative solutions include eliminating sewer discharge requirements, reducing off-site hauling expenses and performing economical and energy-efficient on-site treatment of industrial process wastewater.


Denitrification of industrial wastewater

Researchers at Qita University in Japan have developed a process to denitrify industrial wastewater utilizing a sulphur and limestone packed column. In the autotrophic denitrification unit, micro-organisms containing Thiobacillus denitrificans as a dominant species were attached on the surface of granular elemental sulphur, used as an electron donor, packaged in a column. Limestone granules were mixed with granular sulphur to moderate the decrease of alkalinity during autotrophic denitrification. The stoichiometry and basic kinetics of denitrification were scrutinized in column runs. The effects of minerals like phosphorus on treatment performance were also clarified. Wastewater streams from steel production plants can be treated by this biofilm process.


Membrane filtration system

In the Untied States, USFilter offers PreMPT membrane filtration system to treat wastewater. A PreMPT unit supplied to the City of Carlsbad will produce water for use in landscaping and golf course irrigation. The containerized PreMPT unit is USFilters latest method of providing Memcor continuous microfiltration-submerged (CMF-S) technology for applications that require mobility, a small footprint and reduced installation time and costs. The fully automated plant incorporates remote monitoring capability to reduce operator supervision and is designed to supply between 2.72 million l/d to 5.45 million l/d. The unit also includes the Memcor pressure decay test, a fully automated and highly sensitive integrity test system that allows the operator to directly verify over 4-log reduction of pathogenic organisms such as Giardia lambila and/or Cryptosporidium. USFilters Memcor Products offer flexible, state-of-the-art microfiltration and reverse osmosis (RO) membrane solutions to treat surface water, groundwater, industrial process water and water reuse.


Wastewater aeration system

Biomixer Corp., the United States, designs and fabricates aeration and mixing systems for wastewater treatment. Two units, model 400-85-10 and model 400-60-10, have been installed at the city of Taft under an upgrading programme aimed at compliance with state and federal environmental regulations. The Biomixer units are installed from the surface, requiring no additional infrastructure or draining and provide significant energy savings. The Biomixer fine-bubble system adds oxygen to the process, facilitating discharge of acceptable quality effluent while reducing energy bills by half.

The pre-assembled Biomixer unit is designed to create a healthier and safer environment for personnel and municipalities. Other types of aeration systems may create surface aerosolizing, which releases odours and dangerous pathogens to the air. Since the Biomixer system aerates wastewater from below the surface, versus spraying wastewater into the air, the possibility of toxins being carried away by wind is eliminated. 

Contact: Biomixer Corp., 12600, Yukon Avenue, Hawthorne, CA 90250, the United States. Tel: +1 (888) 2632 560/(310) 2632 560; Website: 

COD reduction in latex effluent

Latex manufacturer Zeon Chemicals Europe Ltd. has awarded a US$1.7 million contract to ACWa Services Ltd. to extend its effluent treatment unit in the United Kingdom. ACWas system comprises a fully automated secondary activated sludge treatment system, including degassing, aeration, settlement and sludge dewatering. Wastewater from Zeons primary treatment DAF unit feeds the ACWa plant. Chemical dosing associated with the existing DAF system will be fully automated to improve DAF operating efficiency. The feed flow-balancing capacity will be raised to provide a homogenous feed to the DAF system. Combined primary and secondary sludge will be stored and a belt press employed for dewatering.

In order to optimize operation of the DAF system, ACWa will implement recommendations from its treat-
ability study that demonstrated 50-60 per cent reduction in the chemical oxygen demand (COD) of effluent. Raw effluent will be diverted when pH, flow or load is beyond the existing works design parameters. New run down screens will be installed to remove gross latex solids present in the raw effluent. A new balance tank will provide 12 h of hydraulic retention time to smooth out loading variations. A new mixer and spray system will reduce foam build-up in the tank. Modifications to the DAF system will provide an averaged flow for secondary treatment. A dissolved oxygen monitor will help control dissolved oxygen in the aeration tank at 2 mg/l. The resulting mixed liquor suspended solids are expected to be 3,500-4,500 mg/l.

Water and Wastewater International, June 2002

Electrolytic process removes phosphates

In Japan, researchers from Gunma University and Waseda University report to have developed an electrolytic process to remove phosphates from wastewater. In this process, ion electrodes are dipped in synthetic wastewater and direct current (DC) applied to coagulate phosphate on the surface of the anode. Experimental results demonstrate that at electric current densities between 0.001 to 0.1 mA/cm2, phosphates can be removed and recovered as phosphate-rich aggregates formed on the anode surface. Reduction in phosphate concentration at bulk liquid were in fairly good agreement with the amounts of phosphate in the aggregates. Moreover, the removal rate of phosphate increased with rise in electric current. In addition, since heavy metal anions like Cu2+ deposit on the counter electrode or cathode, it is assumed that relatively pure phosphate could be obtained by this process.


One-step solution

In the United States, MART Corp. has developed new technology to recycle industrial wastewater from point source and discrete waste streams. It is reported that MART EQ-1 processing system greatly reduces, at times even eliminating, wastewater discharge from the plant. This process has the potential to reduce industrial aqueous waste discharge by up to 90 per cent, recycle industrial wastewater back into the production process, render waste effluent non-hazardous and also save energy.
The MART process encapsulates waste products using adsorption and electrostatic forces. It can remove solid and dissolved metals, hydrocarbons, ink and paint, particulates and dust, and minerals from wastewater. The company worked along with the Environmental Protection Agency, Rochester Institute of Technology, Department of Defence and private industry to develop this technology. 

Contact: Mr. John Freeborn, International Business Manager,MART Corp., the United States. Tel: +1 (314) 5677 222; E-mail: 

Treating high-strength wastewater

In Singapore, researchers have developed a submerged tubular ceramic membrane bioreactor (MBR) to treat high-strength wastewater. In lab-scale trials, a 4 l MBR was applied for treating 2,400 mg COD/l high-strength effluent. A prolonged surface retention time (SRT) of 200 days, compared with conventional SRT of 5-15 days, was investigated with the aim of reducing the amount of disposed sludge. The MBR unit was operated for 142 days in four runs, differentiated by specific oxygen utilization rate (SOUR) and hydraulic retention time (HRT).

It was observed that the MBR unit achieved more than 99 per cent of suspended solid reduction. Mixed liquor suspended solids (MLSS) were found to be adversely proportional to HRT, and in general higher than the value obtained in conventional wastewater treatment facilities. COD removal efficiency of up to 98 per cent was achieved in run 1, when SOUR was in the range of 100-200 mg-O/g-MLVSS/h. COD removal efficiency was greater than 92 per cent, on average, during the next three runs where higher HRT and abnormally low SOUR of 20-30 mg-O/g-MLVSS/h prevailed. The ceramic membrane exhibited significant soluble nutrient rejection when the microbial metabolism of biological treatment broke down.


Treatment of drilling waste

Statoil is employing new methods, including earthworm composting and asphalt production, to treat drilling waste oil-based drilling fluids and water-based fluids. The companys total fluid management (TFM) project aims to help enhance value creation, in part by developing effective techniques for removing and reusing drill cuttings and drilling fluids. The TFM team is working to develop viable environmental strategies and processes for reducing hurdles poised by various types of waste from drilling and down-hole operations. Trials are underway at Norways Jordforsk Research Institute with earthworm used for composting the oily drill cuttings. The worms are fed on cuttings and liquid mixed with animal waste, converting the blend into an excellent fertilizing compost. Trials using oily cuttings for asphalt production are being planned.


Purification of effluents containing heavy metals

In Israel, Veracon Metal Ltd. offers technology that can guarantee the purification of effluents containing heavy metals well below the levels prescribed by authorities. This one-step method is the most economical technology available worldwide. It involves a special reactor that provides the driving force for precipitation of ferrites in heavy metals. As a result, Veracon process achieves treated water quality comparable to that obtained by ion exchange technology, but at a fraction of the cost. High-quality treated water is secured irrespective of the concentration of heavy metals. Additionally, crystalline ferrite is much easier to collect and dry compared with amorphous hydroxides. Salient features of this process include:
l Consistent high quality of treated water;
l Simple separation and removal of solids from treated liquid;
l Solids are crystalline, no amorphous colloids;
l Low-cost operation;
l Automated process that needs minimal operator intervention; and
l Either continuous or batch mode processing feasible.
Some features that ensure long-term profitability for the company are as follows:
l Patent-protected innovative technology;
l Commercial uses for the ferrite precipitate;
l Simple to scale up depending on customer requirements; and
l Almost unlimited market either as a new unit or as add-on to an existing system.

Contact: Mr. Kinarot, D.N. Jordan Valley, Zemach 15132, Israel. Tel: +972 (4) 6709 018 (106); Fax: +972 (4) 6709 014; E-mail:  

Eco-friendly fertilizer from wastewater

In the United States, the Department of Agriculture has developed a process to remove phosphorus from pig production wastewater and transformed it into fertilizers, available in both solid and liquid forms. The new method has several positive implications. Removing phosphorous from wastewater decreases any excess phosphorus that could run off into streams and rivers. During processing, hydrated lime precipitates most of the phosphorus in wastewater as a solid and converts it into marketable phosphate fertilizer. An added benefit is that high pH achieved by this technique eliminates disease-causing pathogens present in the leftover liquid.

The effluent contains a nitrogen-to-phosphorus ratio greater than 12:1 ideal for crop irrigation, which requires an 8:1 ratio. Regular manure offers a ratio of 4 to 1. This higher nitrogen-phosphorus ratio translates into less excess phosphorus on land on which the treated wastewater is applied. A crucial step necessary for the success of this process is the separation of ammonia nitrogen from wastewater, achieved earlier. A patent application has been filed for the process, which will soon be tested at a full-scale demonstration facility.


Vibratory membrane filtration

New Logic Research Inc., the United States, has added an ultra-compact unit to its range of VSEP vibratory membrane filtration systems. The P-50 is aimed at applications with process flows up to 22.7 l/min. This affordable, powerful system provides all the advantages of its larger predecessor, including superior fouling resistance, unbeatable materials compatibility and high solids capabilities up to 70 per cent.

The key to VSEPs fouling resistance is its patented vibrational drive unit. The filter pack vibrates about 50 times per second at an amplitude of of an inch, generating incredible shear force directly on the surface of the membrane. This enables high solids separations in a single pass, something unthinkable in traditional crossflow membrane systems. Fully customizable, P-50 is designed for superior performance across a wide application base, ranging from river water to chemical processing to wastewater. In just 6 ft2 of floor space, this unit can fit into the most crowded production or pilot plant environment.



Artificial aggregates from industrial  sludge

A team from Singapore and Taiwan has studied the potential of converting industrial sludge and dredged marine clay into construction and building materials. Industrial sludge was mixed along with marine clay in various compositions, shaped into round pellets, dried and transferred into a high-temperature kiln where they were heated at 1,135C. The artificial aggregates exhibited more porosity than normal granite. Addition of sodium chloride and increase in firing temperature decreased the densities of the aggregates. 

Contact: Mr. J. H. Tay, School of Civil and Structural Engineering, Nanyang Technological University, Singapore 639 798. E-mail:; Or Mr. C. Y. Chien, Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan.

Paper gives fireproof insulation

In Germany, researchers are striving to develop substitutes to sprayed asbestos for use as fire insulation in load-bearing structures. One such alternative using cellulose recovered from waste paper has been reported by Mr. Wolfgang Christ. According to Mr. Christ, it is all a question of mixing cellulose with the right proportions of mineral fractions. There are several inoffensive boron compounds that melt in contact with fire, forming a protective coating around the fibres. The incombustible mixture sinters, becoming even more solid without causing any significant loss to the materials thermal insulation properties. With the optional addition of graphite, a particular extinguishing effect is achieved. Mixed with standard commercial binders, the material can be processed easily. It adheres well, even in thick layers, and also protects the steel against corrosion. 

Contact: Mr. Wolfgang Christ, Fraunhofer-Patentstelle fur die Deutsche Forschung PST, Leonrodstrasse 68, Munchen 80636,Germany. Tel: +49 (30) 7476 6225; Fax: +49 (30) 7476 6224.

New use for biosolids

In the United States, DuPont Textiles and Interiors (DTI) and others from DuPonts Engineering and Safety organizations have developed a way to use biosolid material for growing hay. Biosolids micro-organisms that have completed their life cycle are a by-product of DuPonts biological state-of-the-art industrial wastewater treatment facility situated at Texas. The wastewater treatment facility processes on average about 4.546 billion l/y of water. Biosolids are dewatered and injected into the ground as a fertilizer for hay, donated to a wildlife park, animal rescue organizations and therapeutic riding centres. Each bale grown using this process is bar coded to ensure that the hay is used in the intended application.


Bridge beams fabricated from recycled plastics

The first all-plastic vehicular bridge built using unreinforced I-beams and other components, fabricated using recycled plastics, is located in New Jersey, the United States. The 42 feet, single-lane, fire equipment access bridge can support a loaded fire truck weighing 16.3 t. The all-plastic bridge encompasses large I-beams supported by posts with 
smaller I-beams spanning between the larger structures. Three inch thick tongue-and-groove decking material provides the road surface. The overpass is not vulnerable to water and weathering effects, is almost indestructible and never requires painting or other maintenance common to steel or wooden structures. Sunlight and other natural elements help form a flimsy protective coating on the surface of the polymer composite and give it a finish that blends well with the natural surroundings.

The Centre for Advanced Materials via Immiscible Polymer Processing (AMIPP) at Rutgers University developed the novel composite polymer material utilizing post-consumer recycled polymers like high-density polyethylene and polystyrene from consumer packaging. Neither of the constituent polymers, found in polystyrene cups and polyethylene milk jugs, would be suitable for structural use by themselves. AMIPP process combines two or more polymers together and then extrudes them to form a fine microstructure. Special characteristics of the material are a result of an oriented microstructure that gives the material unexpected mechanical properties and enables it to be used for bridge I-beams, railroad ties, boardwalk sub-structures and decking, and numerous other applications.


Old tyres yield durable composite

At the Institute of Synthetic Polymeric Materials, Russia, scientists have developed a new application for utilizing waste tyres. Ground into powder and combined with common polyethylene, rubber tyres form a strong and durable composite that can be used for covering roofs. Tyres contain soot, an antioxidant, which makes the composite resistant to oxidation and sunlight. Low-density polyethylene binds powdered rubber particles together, yielding an elastic material. The low-cost composite exhibits good stretching properties. Rubber-LDPE composite was mixed with a small portion of ethylene and vinyl acetate copolymer to improve binding between the polymer and rubber particles. By changing the quantity of polymer, harder composites could be obtained and used for manufacturing roof slates.


Palm shell concrete

Malaysian University researchers report that waste shells from palm nuts can be used to make concrete for buildings and roads. Conventional concrete is a mixture of cement, fly-ash, pulverized burnt fuel from power plants and water. This forms a paste that binds with an aggregate, such as sand or crushed stones. According to the team, crushed palm shells could be utilized as the aggregate. They have come up with a mixture that yields a lightweight concrete that is strong enough for low-rise buildings and roads. The shells do not rot in concrete and the properties of the palm shell-concrete is on par with that of ordinary concrete made using crushed stones.


Using organic wastes

At the University of Florida in the United States, researchers report that sewage sludge has the potential to boost production of certain crops while offering a means to dispose the waste. A study conducted during 1997-2000 investigated the effects of different kinds of sewage sludge versus commonly utilized synthetic nitrogen fertilizer on the forage crop bahia grass. Parameters evaluated include yield, protein and mineral content, and digestibility. Accumulation of heavy metals and nutrients in crops, groundwater and soil were also scrutinized. It was observed that liquid forms of sludge are just as effective as conventional synthetic fertilizer. Minerals such as calcium, phosphorus and iron were higher in crops fertilized with sludge. In a very dry year, water in liquid sludge can also enable nutrients to reach the crops rooting zone more effectively than synthetic fertilizer. Processed liquid sludge is low in pathogens, inexpensive and environmentally safe. An EPA survey has shown that the amount of sewage sludge produced in the country increased from 8.5 t in 1990 to over 12 t in 2000. At the same time, public interest in finding alternative, eco-friendly solutions to waste disposal is also on the rise.


Food scraps make perfect plastic

Researchers at the Hawaii Natural Energy Institute, the United States, have developed a biological reactor that converts a slurry of food wastes into biodegradable plastic. The product thus created can be used to make greener packaging, disposable products like bottles, or even pills that dissolve slowly to release drugs in the body.

Researchers collected food waste, mixed it with water and stored the slurry in a warm, airtight container. After a few weeks, strains of bacteria that thrive without oxygen had multiplied in the mixture. These strains break down the organic molecules, releasing acids as the by-products most commonly lactic and butyric acid. Fresh slurry was added to the container, while a pump siphoned off the acidic product and fed it into a sack-like sheath dangling inside a second vessel. This container holds an aerated suspension of the micro-organism Ralstonia eutropha in a nutrient broth containing phosphates and sulphates. It was observed that acid molecules present in the slurry gradually diffused through the sheath and into the bacterial suspension on the other side, while particulates and other large molecules remain trapped. The bacteria absorb these acids and synthesize them into large polymers that they store as a source of carbon.

The use of a silicone rubber sheath results in the conversion of acids into biodegradable polymer (PHB). However, polyester sheath altered the fraction of acids available to the bacteria and they converted them instead into PHBV, a more tough polymer. Bioplastic polymer makes up around 70 per cent of the bacterial mass harvested from the second container. About 22-25 kg of polymer is obtained from 100 kg of slurry.


Rice husk ash can substitute for cement

Researchers at Angeles University Foundations College of Engineering, the Philippines, have found a substitute for cement. Rice husk ash is reported to be a cement alternative and an ideal additive to decrease corrosion and enhance durability of concrete structures.

Annual rice husk production nationwide exceeds two million tonnes. Generally discarded as agro-waste, about 17-25 per cent of rice husks weight remains as ash when burnt, which can be used as a pozzolana to replace as much as 50 per cent of ordinary portland cement. Silica present in ash reacts with lime in the presence of water to form calcium silicate hydrates that function as a binder. 

Contact: Ms. Luella L. Sadicon, Science and Technology Information Institute, Dept. of Science and Technology, the Philippines. E-mail: 


New microbes clean toxic wastes

Researchers at the Technische Universitat Hamburg-Harburg, Germany, have developed new technology that uses thermophilic micro-organisms for cleaning up hazardous wastes, particularly xenobiotic compounds. Thermophilic organisms were found to be capable of degrading contaminants, between 55C and 75C, under aerobic and anaerobic conditions. The proven technology elucidates degradation pathways, and the isolation and characterization of relevant enzymes in the degradation pathways is facilitated. 

Contact: Mr. Rudi Mueller, Technische Universitat Hamburg-Harburg, Abt. Biotechnologie 11, Denickerstr. 15, Postfach 9U 1052, D 21071, Hamburg, Germany. Tel: +49 (404) 2878 3118; Fax: +49 (404) 2878 2127; E-mail: ; Website: 
Journal of Scientific and Industrial Research, Vol. 61, September 2002

New age toilet

QinetiQ, the United Kingdom, has developed a cheap, clean and eco-friendly toilet for trains that employs microbes normally found in wastewater treatment plants. The Intratech Waste Processing System (IWPS) consists of a macerator, bioreactor and ultraviolet (UV) sterilizer. The macerator chews up solid waste and supplies it into the bioreactor. This aerated tank contains membranes covered with bacteria. Here micro-organisms break down the solids into carbon dioxide and water. While the gas is pumped off, bacteria-free water passes across the membrane. A part of the treated water is sterilized utilizing UV and routed to the flush tank. The remaining part goes through a reverse osmosis unit that filters out the remaining chemicals, such as proteins and urea, making it suitable for washing hands. This system needs servicing once every 30 days, to remove sludge from the bioreactor.

Down to Earth, 15 January 2003

Fungi iron-out asbestos pollution

In Italy, researchers at the University of Torino report to have discovered a fungus that mitigates the toxicity of asbestos fibres. These fibres are harmful partly because they contain iron, which causes the formation of highly reactive chemicals called free radicals, which damage DNA and triggers cancers. Since most soil micro-organisms need iron to produce energy, they grab iron atoms present in soil minerals and concentrate it using chemical hooks called siderophores.

The team has shown that several fungi steal iron from crocidolite, one of the most potently carcinogenic form of asbestos. They have also demonstrated that the iron-stripped fibres cannot generate free radicals. The best iron gatherers were Fusarium oxysporum, a common cause of plant rot, Mortierella hyalina and Oidiodendron maius, a fungus that attacks trees and shrubs and can withstand heavy metal pollution. The fungi bind asbestos fibres in a kind of web of thin strands called hyphae, making them less liable to escape into the air. The far-reaching hyphae networks that fungi spin throughout large areas of soil could immobilize asbestos fibres.


Remediation of oil contamination

In the United Kingdom, scientists at Napier University have come up with a novel approach to bioremediate oil-contaminated soils as well as crude oil wastes at locations subjected to extreme environmental conditions. This method uses bioaugmentation, the addition of microbial cultures or enzymes, and is currently undergoing tests in Russia. The focus of this three-year project is to assess the potential for using immobilized hydrocarbon degrading microbes to clean up diesel-contaminated soil. Other key biotechnical aspects of immobilization under scrutiny are functional structure and taxonomy, i.e. classification, of hydrocarbon-oxidizing bacteria communities.

Partners in the project include the Contaminated Land Assessment and Remediation Research Centre at the University of Edinburgh in the United Kingdom, Hodmarket Kft in Hungary and four establishments 
based in Russia the Institute of Organoelement Compounds of RAS, Institute of Ecology and Genetics of Micro-organisms of RAS, Boreskov Institute of Catalysis and the Kuben State University Biology Faculty. 

Contact: Dr. Jim Philp, 10, Colinton Road, Edinburgh, EH10 5DT, the United Kingdom. Tel: +44 (131) 4552 2462; Fax: +44 (131) 4552 291; E-mail: 
Web-site:  TPI News, Issue 36, Spring 2003


Environmental controls for concrete reinforcers

BRC McMahon, a manufacturer of concrete reinforcing mesh fabrics based in Ireland, has installed a new environmental dust, metal scale and processing waste control layout designed by Dust Control Systems Ltd. Coiled raw steel wire is manipulated on pulleys and reconstituted in a rolling mill, for imparting tensile strength. This flexing of the steel causes the raw material to descale and to shed accumulated rust, dust, soap lubricant in dust form and other waste material.

The new extraction plant is a two-part system comprising a reverse air pulse jet filter system for extracting respirable dust and other waste at its source on the rolling mill. A centralized vacuum system is installed to clean up the floors and enclosures of material not collected at source by the extraction system, specifically the heavier metal scale debris. The DCS C series filter module utilizes spun bonded polyester fabric filter cartridges having an efficiency quotient of 99.996 per cent at dust particle sizes of 0.2 m. The filter medium is cleaned by jets of compressed air injected in pulse form into the cartridges to dislodge dust and provide continuous cleaning of the filtration medium.

Dust dislodged by the reverse air pulse jet drops into the collection hopper at the base of the filter unit from which it is transported for discharge via a rotary valve equipped with butyl tipped blades for low noise and durability at the external wall of the factory. The filter unit is mounted on a steel support structure, with waste being discharged from the collection hopper through a short 
canvas chute to a collection skip outside the building. A single 30 kW extraction fan draws the dust-laden air through more than 3,000 ft2 of polyester filter material, the overall extraction capacity of the filter plant is almost 10,000 ft3/min. The filter installation contains sixteen thermal bonded polyester fabric filter cartridges measuring 325 mm in diameter and 1,400 mm in length, each configured vertically. 

Contact: Dust Control Systems Limited, Churwell Vale, Shawcross Business Park, Shawcross, Dewsbury WF12 7RD, Ireland. Tel: +353 (01924) 482 500; Fax: +353 (01924) 482 530; E-mail: 

Treating solvent-laden gas streams

In the United States, Adwest Technologies Inc. offers Retox regenerative thermal oxidizer (RTO) system as a cost-effective solution to convert solvent-laden gas into water vapour and carbon dioxide (CO2). This unit comprises a reinforced, internally insulated chamber that is filled with ceramic heat exchanger media. The gas flow is automatically controlled by a zero-leakage poppet valve unit, which changes the direction of the gas flow at regular intervals through the use of an integral programmable logic control with remote modem-based telemetry diagnostics.

The oxygen present in the process gas ensures complete combustion when the ignition point is reached in the oxidizer. Process hydrocarbons are transformed into CO2 and water. With sufficient concentration of solvents in the incoming process gas (400+ ppm), the exothermic solvent heat release self-sustains the flameless destruction of VOCs, without the need for supplemental auxiliary heat energy from the burner after the initial 1.5 h cold start-up. The high degree of heat recovery achieved is a result of regenerative heat transfer.

Application areas for the Retox RTO oxidizers include film/adhesive coating, printing, flexible packing, spray driers, metal coating/bake ovens, wood furniture coating, plasticizers, screen printing, aerospace coating, laminating/treating, circuit boards/wafer chips, food processing/bakery ovens, sludge driers, foil coating/metallizing, wastewater, etc. 

Contact: Adwest Technologies, 1175, North Van Horne Way, Anaheim, CA 92806 2506, the United States. Tel: +1 (714) 6329 801; Fax: +1 (714) 6329 812; 
E-mail: Website: 

New process

Airborne Pollution Control, Canada, offers proven technology for flue gas purification. An integrated demonstration plant is being developed to showcase this three-stage process. It employs proprietary sodium bicarbonate regeneration process. The sodium sulphate by-product is regenerated into two end products sodium bicarbonate, which can be reused in the scrubbing process, and a fertilizer, obtained by the conversion of ammonia by-product through a patented granulation technique. 

Contact: Airborne Pollution Control, Suite 205, 6223, 2nd Street SE, Calgary, Alberta T2H 1J5, Canada. Tel: +1 (403) 2537 887; Fax: +1 (403) 2531 484.


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