VATIS Update Waste Management . Jul-Aug 2003

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Waste Management Jul-Aug 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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Exposing traffickers in environmental goods

The United Nations has stated that illegal trading in hazardous waste, toxic chemicals and ozone depleting substances as well as endangered species is a profitable multi-billion dollar industry. According to a United States government report, local and international crime syndicates worldwide earn up to US$31 billion a year by dumping toxic wastes, smuggling banned hazardous compounds and exploiting and trafficking protected natural resources. Key international organizations such as Interpol and the World Customs Organization have joined hands with the United Nations to provide better support for customs officers, who are the first line of defence in dealing with such activities.

Customs officers can now access a specially targeted Green Customs website with information, advice and details of training which enable them to easily recognize and apprehend criminals dealing in environmental commodities. The United Nations and other international bureaus were involved in setting up the website. Enforcement of new and future international conventions would require additional training for the customs officers. The first to be scheduled will be the national implementation of the Rotterdam Convention on the Prior Informed Consent Procedure for Hazardous Chemicals and the Stockholm Convention on Persistent Organic Pollutants.


Improved waste management abates public health hazard

The United States and Asia Environmental Partnership (US-AEP) has been striving to enhance awareness with regard to the dangers posed by biomedical waste in the absence of adequate economic as well as infrastructure capabilities. By means of multiple exchange and training programmes, Indian public and private sector decision makers have started to focus more resources and efforts towards biomedical waste problems. In Mumbai, improved management practices have facilitated hospitals to achieve significant reductions in medical wastes generated on a daily basis. New technology and handling techniques introduced by US-AEP have reduced the weekly release of about two tonnes of untreated biomedical waste in unsecured landfills.

In February 1999, US-AEP attracted over 500 participants and extensive press coverage on the radio, TV and print by sponsoring the first National Conference on Biomedical Waste Management at Baroda as well as the Southern Regional Biomedical Waste Management Workshop at Chennai, after startling new regulations established criminal sanctions on hospital officials not adhering to proper waste management techniques. During 2002, US-AEP helped create a resource centre for medical waste management, which will be developed in cooperation with the Environmental Protection Training and Research Institute, Hyderabad.


Network to facilitate recycling in Asia

Japan and China intend to set up a recycling programme that could spread across Asia. The first phase of this initiative will be to establish a system in which television parts collected in Japan will be reused in China. This cooperation would then be extended for recycling plastics in general. Using the European Union as an illustration, the governments envisage agreements spanning the entire Asian region for recycling activities. Meetings between officials of the Japanese Ministry of Economy, Trade and Industry and Chinas State Economic and Trade Commission, scheduled to take place in July this year, will initially focus on China utilizing cathode ray tube (CRT) glass collected in Japan.

The introduction of a home appliance recycling legislation in 2001 resulted in a build-up of stocks of CRT glass, for which there is no local market in Japan. According to officials, it is necessary for both governments to have the ability to track the flow of materials through to actual reuse. Also, China has evinced interest in recycling plastics found in industrial waste products. The reason being high labour costs in Japan make it economically worthwhile for China to reprocess items.


Battery recycling in Europe

In the European Union, the Environment Directorate (ED) announced fresh consultations on plans to draft a comprehensive law pertaining to the collection and recycling of waste batteries. It is to be among the first legislative proposals to pass through an extended impact assessment under the European Commissions better regulation initiative. This step effectively cancels an earlier draft law by ED in October 2001, bringing Europe back to square one.

The new consultation paper invites opinions from stakeholders on the positive and negative facets of three key points collection targets, recycling targets and cadmium. Three target ranges have been proposed for battery collection rates 30-40 per cent, 60-70 per cent or 70-80 per cent. Car batteries would have a separate target between 70 to 100 per cent. The proposed target ranges for battery recycling rates varies from 45-55 per cent at the lower end and 65-75 per cent at the higher end. In addition, ED is seeking views on introducing producer responsibility for spent batteries, with free take-back along the lines of the newly minted legislation governing waste electrical and electronic equipment. For regulating Ni-Cd rechargeable batteries, the paper sets out several possibilities, that include separate collection and recycling targets varying between 60-90 per cent and 50-80 per cent, respectively, and a ban on cadmium wherever commercially viable substitutes are available.


Private sector to manage waste

The sanitary system at New Delhi, India, is being privatized, with the final contract awarded by 15 August. The Municipal Commissioner of New Delhi, Mr. Rakesh Mehta, has stated that private sector participation in the management and segregation of solid wastes in six of the 12 zones of the municipal corporation would create additional job opportunities for about 15,000 people. The private companies would be responsible for designing and maintaining a separate collection mechanism for solid wastes and their transportation to sanitary landfill sites in the zones, which generate 3,132 t/d of garbage.

According to Mr. Mehta, in the pre-transportation stage, the operator would design, procure, operate and maintain a system, including equipment and vehicles for solid waste collected from door-to-door to the dhalao (dump) and transfer stations in an isolated manner. The operator will redesign existing dhalaos and dustbins to allow segregation and storage of waste, design and set up transfer stations/sorting and recycling centres at a site identified by the municipal corporation. The private players are also expected to design a transportation system and equipment to allow for transportation of wastes in covered containers with a colour coding for biodegradable, recyclable and other dry waste. They will have to upgrade, operate and maintain a transport workshop as well as procure machinery, equipment and vehicles for the system.


Scheme to dispose used tyres

In the Philippines, the Department of Environment and Natural Resources (DENR) has forged partnerships with tyre industry associations to devise an effective retrieval and disposal scheme for used and worn out tyres. DENR has signed a Memorandum of Agreement (MOA) with the Tyre Importers and Traders of the Philippines (TITAP), Tyre Manufacturers Association of Philippines (TMAP) and Philippine Retreaders Association (PRA). Under the MOA, through its National Solid Waste Management Commission DENR will provide technical assistance to TITAP, PRA and TMAP in implementing the used tyres recovery programme, including coordination of related activities at both tyre industry associations. Proponents of the MOA will serve as information banks in the development of advocacy materials for the programme that would assist other organizations in adopting retrieval schemes and available tyre reuse/recycling technologies. The project also discourages burning of used tyres.


Biotechnology helps lower water pollution

In China, Sichuan province is testing a biological technique for reducing pollution in its rivers. Developed by the Haifa Group and the University of Agriculture, this technology has proved to be very effective during a month-long trial period in Funan river, Chengdu, and will be implemented in larger areas of the river. The CMF technology comprises an effective microbial thallus compound and oxygenating agents.

The Haifa Group has developed 80 kinds of solid microbes and environmentalists will decide how many or what kinds of microbes should be employed in accordance with the ratio of organic and inorganic substances present in the water. When the microbial compound is injected into water, the microbes activate in about 30 minutes and replicate every 15 minutes. Considering that a gram of the microbial compound has 6-8 billion microbes, organic matter is eliminated quickly. The initial investment for this treatment is US$12.4/m2, effective for a period of 20 years, with no reinvestment.



Extrusion process for recycling car seats

In the United States, the Centre for Excellence in Polymer Science and Engineering at the Illinois Institute of Technology has patented a solid state sheer extrusion technology (SSSE) and apparatus that could be used to recycle polyurethane foam from waste cars, along with a broad range of other polymer wastes and rubbers. This technique pulverizes polymeric material thus yielding fine powders that have various applications for industry. A key benefit or SSSE is that it can be applied economically to many types of natural and synthetic polymer wastes. 

Contact: The Office of Public Relations, Illinois Institute of Technology, the United States. Tel: +1 (312) 5673 104

Website: or Website: 

Recycling mass polymer wastes

The Institute of Synthetic Polymeric Materials, Russia, has developed a new elastic deformation technology to recycle mass polymer wastes. The technique, based on the action of pressure on the material under simultaneous shearing strain, can be used for recycling polymer and rubber wastes into new materials. In this process, elastic energy gets accumulated in the materials, which, as a result of the shearing strain is realized in forming a new surface, or initiates a passing of chemical reactions. The new method allows to obtain finely dispersed powders of various rubber wastes (without metallic impurities), powder materials of linoleum and various kinds of artificial leathers, and a range of secondary thermoplastic wastes.

A key benefit of elastic deformation process is its universality, low power consumption and high productivity, as well as the possibility of creating a wide spectrum of novel materials on the basis of polymer and rubber wastes. 

Contact: Institute of Synthetic Polymeric Materials, 70, Profsoyuznaya Street, Moscow 117393, Russia. Tel: +7 (095) 3359 100.


PET recycling

In Austria, Erema Engineering Recycling has developed special technology to recycle PET. The patented VACUREMA process ensures high technical reliability, cost-efficiency and quality of the finished pellets. In this method, washed polyester flakes from post-consumer waste is transformed into pellets that have been confirmed as 100 per cent suitable for reuse in PET bottles. By combining VACUREMA extrusion system with the Erema crystallization drier, used PET bottle flakes are turned into top quality food-contact grade PET pellets with increased IV, at a low cost. Erema realizes in-line processing by placing the die right behind the VACUREMA extrusion system to produce thermoforming sheet or spun fibres, without detours like prior repelletizing and external pre-crystallization. This lowers production costs and logistics, raising the value added to the product.

In the classic, compact Erema plant design, preheated, dried and crystallized material is conveyed from the patented vacuum reactor/pre-drier directly to the extruder. This is the requirement for minimal or almost no viscosity loss for thick and also thin-walled PET material that guarantees high-quality recycled pellets. Starting with bottle flakes, the crystallization drier is fed through conveyor belt or conveyor screw. The material is continuously preheated, dried and crystallized in a crystallization drier in one working step. The material is thermally insulated as it moves in to the VACUREMA reactor/extruder combination through vacuum lock. Appropriate holding time in very high vacuum/high-temperature environment effectively removes contamination from the PET flakes, minimizes residual moisture and increases the viscosity to virgin material levels. The actual degree of contamination in PET flakes can be measured and monitored using appropriate sensors on the VACUREMA reactor. These PET flakes are fed continuously, still under vacuum, and directly to the extruder, where they are plasticized, homogenized and further degassed before being fed to a fine filter with an integrated, automatic self-cleaning system.

The continuous extrusion process facilitates, optionally, continuous on-line IV monitoring/recording of the processed PET material. 

Contact: Erema Engineering Recycling, Maschinen und Anlagen Ges.m.b.H, Freindorf - Unterfeldstrae 3, P.O. Box 38, A-4052, Ansfelden/Linz, Austria. Tel: +43 (732) 3190-0; Fax: +43 (732) 319 023



Reclaiming oil from waste plastics

In Japan, Hitachi Zosen Corp. has developed an oil reclamation system for waste plastics. The process comprises a crusher, thermal cracking retort and oil condenser. At around 400C waste plastics start to crack and produce a hydrocarbon oil, such as fuel or chemical feed. Important features of the process include:
  • Simple and easy to maintain
  • Processes polyethylene, polypropylene, polystyrene, polyester, polyamide, acrylic resin, etc.
  • Not affected by the presence of small quantities of sand, grass,paper, cloth and metal and
  • The system is quite safe since there is no valve from the retort to the stack in the main flow and ambient pressure operation is attainable.

Contact: Hitachi Zosen Corp., New Environmental Systems Division,Overseas Business Department, 7-89, Nanko kita 1-chome, Suminoe-ku, Osaka 5590034, Japan. Tel: +81 (6) 5690 063; Fax: +81 (6) 5690 079.


Automated recycling

RRT Design and Construction, the United States, has installed an automated electronic plastics recycling system. The innovative system is designed to accept post-industrial and commercial plastics, principally electronic equipment casings, for resin separation. Developed by CTC, an applied R&D and professional services organization, this system presents a sound solution for eco-friendly and economical recovery of valuable resources from electronic wastes. 

Contact: RRT Design and Construction, Melville, New York, the United States. Tel: +1 (631) 7561 060; Fax: +1 (631) 7561 064




New process

Researchers at North Carolina State University, the United States, have developed a unique recycling process for some of the most common kinds of polymers. The new process has two distinct elements. First, the process is run in a machine, called twin-screw extruder, which has high throughputs and as such facilitates substantial quantities of polymers to be processed in a very short time. The extruder softens polyethylene terephthalate (PET) and creates very thin films, enabling interfacing of high molecular weight polymer with other materials, either ethylene glycol or methanol, to reduce the molecular weight of the polymer.

Secondly, supercritical carbon dioxide (CO2) is fused with ethylene glycol or methanol, which reduces the viscosity of the polymer, making it easier to process and allows better contact between the materials. At the end of the process, CO2 vented from the extruder is run through a condenser, where the dissolved impurities can be removed. CO2 is then recycled. The conversion is carried out under efficient processing conditions and is a single-step, environmentally benign process. In addition, this process could be tailor-made for materials of different molecular weights.


Recycling through gasification

Sumitomo Metal Industries Limited, Japan, is entering the area of waste material recycling by employing a high-temperature gasification melt furnace. The new system is ideal for treating plastic wastes that are normally disposed off in landfills. Key characteristics of the gasification melt furnace are listed below:
  • Minimizes generation of dioxins: The furnace melts and decomposes wastes at elevated temperatures and provides rapid cooling of the waste gas in an instant, minimizing production of dioxins. The furnace is suitable for the treatment of wastes that contain chlorine or bromine, which are sources of dioxins;
  •  High-quality of slag: Slag with extremely low levels of heavy metals and dioxins, typically produced from shaft-type furnace units, is obtained. Waste containing a large amount of incombustible materials also yields high-quality slag at volumes similar to those produced by blast furnaces, and can be used as aggregate for roadbeds, asphalt and cement;
  •  Recovery of high-calorie energy gas: Clean gas obtained by thermal decomposition of wastes could be used in boilers or high-efficient gas engines to generate electricity as well as for use directly as fuel gas;
  • A variety of difficult wastes, including combustible plastic or oil wastes, incombustible ASR wastes, mixed construction wastes, wastes recovered from the ground, etc. can be treated; and
  • Metals and other valuables can be separated and recovered at every stage of the treatment procedure, offering superior recycling performance owing to effective utilization of slag and gas.


Chemical process for PET recycling

Officine Costarelli is offering a cost-effective chemical process that recuperates the basic ingredients of PET, terephthalic acid and ethylene glycol in a pure chemical condition. Waste plastics are first washed and shredded into flakes in a washing plant, which can also remove paper labels. PE/PP are eliminated in a Sink-float tank and the flakes are dried and cleaned once again in a centrifuge. The next step involves heating flakes in a special extruder and adding the reacting ingredient. PETs molecular chain is degraded and a water-soluble substance produced. Owing to the difference in binding value to the molecular chain of PET, additional ethylene glycol is mixed in a closed loop and the resulting compound is dissolved in distilled water.

Non-reacting plastic materials are then separated from the fluid solution and treated in a different process.The reacting additive brings about the chemical separation of terephthalic acid from ethylene glycol. By adding a strong acid, terephthalic acid is set free while the reacting additive joins with the acid, and both are recuperated. This procedure is carried out in a centrifuge with special filters. Recuperation and drying/crystallization of terephthalic acid is done in a microwave furnace. The solution of ethylene glycol with water is distilled and the recuperated ethylene glycol is stored for delivery. The two basic PET ingredients, terephthalic acid and ethylene glycol, are both retrieved in technical, pure condition. 

Contact: OCI GmbH, Grienbachstrasse 17, CH 6301 Zug, Switzerland. Tel: +41 (81) 3531 685; Fax: +41 (81) 3535 109; E-mail: ; Or OCI GmbH Engineering Services, Industriestrasse 1, D 15517 Furstenwalde/Spree, Germany. Tel: +49 (3361) 376 484; Fax: +49 (3361) 376 562.


Bumper to bumper

In the United Kingdom, researchers at the University of Leeds, aided by industry partners, have developed a new technology that can literally convert old car bumpers into new ones. The novel recycling process integrates pyrolysis with physical separation. Composites are broken down into gas, oil, a small amount of carbon and fibre. The recycled oil and fibre can both be reprocessed into composite plastics. According to Prof. Paul Williams, Pyrolysis involves heating the plastic in the absence of oxygen so that it does not burn. As the process operates at a temperature much lower than needed for burning, fibre retains most of its original toughness instead of becoming brittle. Both oil and fibre can be processed back into composite plastic or reused. 

Contact: Prof. Paul Williams, Dept. of Fuel and Energy, University of Leeds, the United Kingdom. Tel: +44 (113) 3432 504



Electrostatic plastics separation technique

In the United Kingdom, researchers at the University of Leeds, aided by industry partners, have developed a new technology that can literally convert old car bumpers into new ones. The novel recycling process integrates pyrolysis with physical separation. Composites are broken down into gas, oil, a small amount of carbon and fibre. The recycled oil and fibre can both be reprocessed into composite plastics. According to Prof. Paul Williams, Pyrolysis involves heating the plastic in the absence of oxygen so that it does not burn. As the process operates at a temperature much lower than needed for burning, fibre retains most of its original toughness instead of becoming brittle. Both oil and fibre can be processed back into composite plastic or reused. 

Contact: Prof. Paul Williams, Dept. of Fuel and Energy, University of Leeds, the United Kingdom. Tel: +44 (113) 3432 504



Electrostatic plastics separation technique

Plas-Sep Ltd., Canada, is offering technology that employs naturally occurring charge transfer processes to sort plastic wastes, with up to 99.5 per cent purity in a single pass. This dry process, developed at the University of Western Ontario, can be utilized in various industrial or commercial applications if plastic waste is produced and recycling is essential. The new technique can be used to reprocess off-spec products in the plastics industry as well as to recover post-industrial plastics generated in different sectors automotive, appliance and electronics. The separation procedure relies on the principle of electrostatic charge transfer. When two dissimilar substances are brought in contact with each other, charge transfer occurs. One material will take on a positive charge while the other assumes a negative charge. The polarity that the material attains is dependent on the triboelectric series. Based on where a material lies in this series in relation to the reference material, the charge polarity a material will take on when brought into contact with another can be predicted.

The technology comprises a rotating drum that lies at an angle and revolves at 20 rpm. An automatic feed system conveys dry 2-5 mm sized material into the rotating drum where it tumbles over and over, initiating contacts and producing an overall charge transfer, as it walks down the drum to the separation chamber. The charged material then falls from the drum into a horizontal electric field that is created by two charged electrodes located on opposite sides of the separation chamber. Once the particles begin to fall into the field, they deflect towards the electrode of opposite polarity and are collected in trays located at the bottom of the chamber. Material located closer to the sides where the electrodes are located are of higher purity and those falling in the middle of the chamber can be collected and reprocessed. 

Contact: Plas-Sep Ltd., 95, Cumberland, Crescent, London, Ontario N5X 1B7, Canada. Tel: +1 (519) 6600 287; Fax: +1 (519) 6606 913.


Fuel oil production using waste plastics

In China, the Beijing Sanlu Environmental Project Institute has patented a process for producing liquid fuels from waste plastics. Plans are afoot for the construction of a facility with a production capacity of about 4,500 t/y of fuels, using 5,000 t/y of waste plastics. In this process, the waste is sent into a gas receiver and then into a special liquefying process. In the gasification furnace, the liquid is converted into high polymers and oil vapour by catalysis and cracking. Finally, petroleum, diesel and kerosene oil can be fractionated through distillation. The conversion rate of plastic into liquid fuel is around 70 per cent.



New high vacuum steam autoclave

Bondtech Corp., the United States, offers Bondtech treatment process for medical wastes. The treatment systems include custom-designed and sized high vacuum steam autoclaves, external insulation, internal track, complete valves and piping, steam ejector or liquid ring vacuum pump, steam condenser and loading ramp or lift table. Optional automatic loading units and low-speed, high-torque custom-designed shredders are also available. Salient features of equipment based on Bondtechs proven technology include:
  •  Ruggedly designed and built for commercial use;
  •  Hydraulic quick-opening door and locking ring;
  •  Vacuum pump for high vacuum operation;
  • Temperature probes for additional protection assurance;
  • Programmable control system for precise operation;
  • Recorders for monitoring time, date, pressure and temperature;
  • Unique condenser removes excess moisture, thus enabling weight reduction at the time of disposal;
  • Packaged and modularized for easy installation; and
  • Built for safety under the ASME Boiler and Pressure Vessel Code, Sec. 8, Division 1.

With a waste treatment capacity varying from 90 to 3,175 kg/cycle, the autoclaves enable significant cost savings by employing high temperature along with high vacuum 
in combination with saturated steam. A hinge mounted door promotes full movement to a fully open position. The breech lock type door incorporates a safety interlock to prevent the door from opening while under pressure. 

Contact: Bondtech Corp., 2400 N. Hwy. 27, Somerset, Kentucky 42503, United States of America. Tel: +1 (606) 6772 616; Fax: +1 (606) 6769 157



Researchers sterilize wastes using solar energy

In Australia, a team at the University of Sydney has developed a solar-powered oven for sterilizing medical waste. The oven, nick-named Prometheus, operates even in cloudy or rainy conditions. It consists of a sterilization chamber connected to a set of long water-filled copper U-tubes that are encased in evacuated solar collector tubes, highly efficient collectors of thermal energy. Their optically sensitive surface permits visible light and ultraviolet radiation to pass in. Radiation is absorbed as heat, while vacuum between the glass layers acts as an insulator.

The tubes can work at all times since vacuum does not permit heat loss from convection or conduction. The energy gathered when sunlight falls on the collectors is used for heating water. This establishes a thermosiphon effect in which water is heated until it evaporates and steam thus obtained is superheated. The system reaches equilibrium at 121-134C, an appropriate temperature range for steam sterilization. The ingenious autoclave recently won the topmost honour in an international competition that featured affordable tech-nologies for biomedical waste treatment in developing countries.


On-site waste processing unit

Univec, the United States, is offering Demolizer system for on-site biomedical waste processing, containment and disposal. The new system comprises a computerized sterilization module and disposable 3.785 l metal waste collection containers. While a container is used to collect sharp wastes scalpels, syringes, needles, etc. another one is used to gather red bag (soft) wastes. The processing unit incorporates state-of-the-art electronic controllers that assure operation within the approved parameters. In case of malfunction, the system shuts down and prevents removal of the unprocessed wastes. After completion of each successful cycle, a pressure-sensitive label is issued confirming that the correct operating parameters have been met and the processed waste has been properly sterilized. This printed label eliminates the cumbersome medical waste tracking forms currently used. A sophisticated antibacterial, antiviral and anti-odour filtration unit is used together with a sophisticated air flow pattern to ensure that odours and contaminants are captured and processed.

The Demolizer unit employs space-age ceramic insulation along with a sophisticated air flow pattern to maintain the exterior of the unit at a cool temperature during operation, even when the system reaches its maximum temperature. It complies with the Microbial Survivability Test for Biomedical Waste Incinerator Emissions. Those who can benefit from the Demolizer system include allergists, paediatricians, dentists, dermatologists, veterinarians, city health departments, etc. 

Contact: Univec, 22, Dubon Court, Farmingdale, NY 11735, United States of America. Tel: +1 (631) 7772 000; Fax: +1 (631) 7772 786



New incinerator

Furukawa Co. Ltd., Japan, offers a pyrolizer to process wastes. Unlike an incinerator, the pyrolizer does not burn the wastes but combusts only gaseous compounds that are produced when waste is pyrolized in a low-oxygen environment. As such, controlled combustion (400-600C) is feasible and the density of dioxins at the outlet is very low. Features of the new and compact unit include:
  • Disposal temperature as well as furnace inner pressure are controlled automatically to keep the pyrolysis gasification quantity within proper range. Therefore, it is strong to load change and its disposal range varies from vinyl chloride, rubber and plastics to raw rubbish
  • Use of a special sealing method (patent-pending) wherein some resin materials are used together with a water-cooling device facilitates air tightness recommended for high-temperature pyrolysis and
  • An electric heater provides the thermal source and no fuel is used. Therefore, noise and exhaust gas are reduced.

Contact: Furukawa Co. Limited, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 100 8370, Japan. Tel: +81 (3) 3212 8929; Fax: +81 (3) 3287 0279

Website: or 

Pyrolysis of biohazardous waste

Statewide Medical Services, based in the United States, offers a high-temperature pyrolysis system as a cost-effective choice for pollution-prone incineration as well as other non-pyrolytic waste disposal units. This system eliminates pathogens by exposing wastes to temperatures exceeding 1,204C. Waste is gasified in a closed pyrolysis chamber by applying heat from below. The waste mass remains undisturbed by the introduction of process air or mechanical agitation, thus there is no opportunity for the generation of particulates or fly-ash. Fumes from the waste pass into a high-efficiency afterburner whose unique design promotes flame-front activity, reducing the gases primarily into carbon dioxide and water. Ultimate reduction of the coke-like ash to 15 per cent of initial weight and volume is typical. 

Contact: Statewide Medical Services, 3601 East 9th Street, Indianapolis, IN 46201 2511, United States of America. Tel: +1 (317) 6340 801; Fax: +1 (317) 6340 802



Waste disposal by employing plasma

NKK Corp., Japan, has developed a non-transfer type plasma melting system that is ideal for disposing medical wastes. Unlike conventional transfer-type plasma guns, the new system completely melts the waste into non-toxic slag. It uses a furnace comprising a thermal decomposing chamber and a melting unit. By injecting plasma heated to as high as 5,000C into the furnace, medical waste is decomposed and melted, reducing its volume to 1/250th its original volume. It is then vitrified to form slag.

The furnace employs three plasma guns, which are the smallest in the world among non-transfer types. Another salient feature is the low operating costs since air is used in place of nitrogen or argon gas, as found in conventional furnaces. The system also offers notable savings in installation space. 

Contact: NKK Corp., 1-1-2, Marunouchi, Chiyoda-ku, Tokyo 100 8202, Japan. Tel: +81 (3) 3212 7111; Fax: +81 (3) 3214 8400

Website: or 

Plasma-based treatment technology

The Institute of Problems of Electrophysics, Russia, has developed a technique for on-site destruction of toxic medical wastes. The innovative technology is based on the organization of optimal bi-zones and a high-temperature regime of medical waste destruction with subsequent multi-step detoxification of flue gases and decontamination of solid remainders. AC plasma generators are used to supply temperature in the reactor within stipulated limits.

Though intended primarily for on-site destruction of toxic medical wastes, this technology can even be used, with some modifications, to dispose other kinds of toxic solid compounds. 

Contact: Institute of Problems of Electrophysics, 18, Dvortsovaya nab., St. Petersburg 191186, Russia. Tel: +7 (812) 3116 575/3151 757; Fax: +7 (812) 3115 056




Recovering precious metals from waste

Electronic wastes generated in the United Kingdom are being shipped to copper smelting plants in Sweden and Belgium. However, as such units accept materials that are only above a certain metal concentration, it is now more difficult to dispose low-level materials. This scenario could soon change if a new process developed by a team at the Imperial College yields successful results. According to researchers, the clean process recovers nearly all the precious metals and heavy metals from electronic wastes. Prof. Geoff Kelsall states that The essence of the process is its ability to dissolve all the metals non-selectively and then recover them selectively or non-selectively. Though it is not possible to retrieve everything, a wide range of metals can be recovered.

The process utilizes two reactors a leach reactor and an electrochemical reactor. Using anodically generated chlorine, the leach reactor dissolves the metal fraction. The electrochemical reactor has two functions. It not only generates the reagent needed to dissolve metals but also recovers, from solution, the metals dissolved in the leach reactor. The overall process involves feeding electrical energy to transfer metals present in the scrap to the reactors cathode, which produces only de-metallized waste. Researchers have demonstrated the feasibility of this technique in selectively recovering metals from electronic scrap.


Recycling fluorescent tubes

Environmental Lighting Solutions, New Zealand, offers an eco-friendly procedure for recycling fluorescent tubes. This technique removes at least 97 per cent of mercury from the tube in around 15 seconds. Mercury settles in sludge, which can later on be distilled to extract mercury for reuse. The recovered glass can also be recycled. This new process has the potential to lead to recycling of other lighting equipment. 

Contact: Mr. Kenny Buchanan, Environmental Lighting Solutions, New Zealand.Tel: +64 (0274) 970 141/(07) 8584 092; E-mail: ; Or Mr. Lins Kerr, Technology New Zealand, New Zealand. Tel: +64 (04) 9177 804


Website: or 

New technique to process printed circuit boards

In the United Kingdom, researchers from Cambridge University, Alpha-Fry Ltd. and EA Technology have together developed and patented a technique to process printed circuit boards. The new integrated strategy enables separation of components for resale, the solder leached and re-deposited as a solder alloy and the shredded boards to be reused as a binder in aggregate use. A leaching agent is employed to release all the valuable electronic components like chips or condensers for recycling and to recover precious metals and other materials from shredded boards.

The key to this technology is the development of a selective leaching agent that is highly effective at dissolving solder utilized in the circuit boards and yet has no effect on the performance of the electronic parts. The selective leachant comprises fluoroboric acid containing a titanium redox couple. The novel leachant dissolves lead and tin content in exactly the same ratio as the solder, leaving the copper content on the boards intact. This process could even be employed on shredded boards after they have been treated to remove aluminium and ferrous scrap. The solder is then electroplated from the leaching agent, which can later on be regenerated.


Dismantling mobile phones

At Nokia, the on-going Design for Environment programme is aimed at minimizing material and energy use whilst maximizing recovery and recycling of its products. A team of researchers at the Nokia Research Centre, Helsinki University of Technology, Finnish School of Watchmaking and the University of Art and Design Helsinki have developed a new process for heat disassembly of portable devices. The concept is to disassemble a mobile phone via a heat-activated mechanism without any contact. By making use of a centralized heat source like laser, the shape memory alloy actuator is activated and the mobile phone covers are opened. The battery, display, printed wiring board (PWB) and mechanical modules are separated, which can then be recycled in their material-specific recycling methods.

The essential temperature for disassembly is about 60-150C. Lower temperature may lead to dismantling of the phone by itself, for instance in a hot car, and if it were higher the plastics would melt. The new heat-activated mechanism is a fast and low-cost procedure when compared with manual dismantling. The heat-activated disassembly required only two seconds and the only cost is the investment in a disassembly line. However, additional refinements are necessary prior to commercialization. Also, other disassembly processes for electronic equipment are being investigated. One of the option is dismantling by robots.



New alternative for greener bleaching

Hydrogen peroxide is used widely in industrial bleaching processes; but until recently, very few alternatives were available to handle the process wastewater in an eco-friendly way. At Idaho National Engineering and Environmental Laboratory (INEEL), the United States, researchers have uncovered that an enzyme obtained from a microbe that thrives in the depths of a hot spring pool in Yellowstone National Park could provide the key to greener industrial bleaching. The new catalase enzyme from a Thermus brockianus microbe likes extreme conditions, performing best at temperatures around 90C and in highly alkaline pH of more than 9. Within the organism, the enzymes normal role is to degrade hydrogen peroxide that is produced naturally by cellular activity, thus protecting cells from oxidative stress, the biological equivalent of rust.


New process to treat liquid organic waste streams

C-Tech Innovation, located in the United Kingdom, has developed an electrochemical technology based on the high reactivity of electrons and their potential to generate highly oxidizing species to degrade toxic and organic species. The new process can treat very high toxicity or very dilute flows of liquid organic wastes from various manufacturing processes. It has been used in C-Techs Dished Electrode Membrane (DEM) cell, which features a plate-and-frame design where the dished electrodes are arranged between pairs of hollow square frames. This type of arrangement permits several electrodes to be mounted in line, thereby creating a robust system that is capable of dealing with variable flow rates. The system has a small footprint and is reported to be easy to maintain.

The electrochemical technology may also be used in conjunction with an existing treatment method. 

Contact: Mr. Arnold Black, C-Tech Innovation, Capenhurst Technology Park, Chester CH1 6EH, the United Kingdom. Tel: +44 (151) 3472 914; Fax: +44 (151) 3472 901



TPI News, Issue 36, Spring 2003

Sequential bioreactor

co quipement FEP Inc., Canada, has designed a sequential bioreactor for treating wastewater and filtrates. This unit can reduce biodegradable organic load and remove nutrients (TKN, NH4, N and P) from domestic or industrial wastewater and filtrates. It operates in batch mode and can significantly reduce the load in the affluent stream through appropriate selection of automatically controlled sequences. The units size depends on the mass characteristic and biokinetic constants of various types of wastewater.

BioSequencer unit includes a hybrid aeration system (the nozzles can inject air and/or recirculate liquids) and a static or floating settling tank. This type of reactor runs in fast feed mode, creating a biological selector that promotes contact between the substrate and micro-organisms as well as growth of specific bacteria, in particular agglutinating bacteria. Successive use of anoxic, anaerobic and aerobic modes removes organic matter and nutrients. Purging of the mixed liquor after each batch facilitates monitoring of the sludge age, which will be about 20 days. 

A standard BioSequencer can treat flows between 20,000 and 40,000 m3/d. The dynamic BioSequencer has no limitation. The percentage of organic matter removed can be as high as 95 per cent. For industrial or pharmaceutical effluents, treatment period is in the vicinity of around 40 days. 

Contact: Mr.Gaetan Desjardins, President, co quipement FEP Inc., 3330 boul. des Entreprises, Terrebonne, Qubec J6X 4J8, Canada. Tel: +1 (450) 4777 879;Fax: +1 (450) 4777 880


Website: or 

Recovering water and valuable chemicals

Controlled Atmosphere Separation Technology (CAST) systems being offered by CASTion Corp., the United States, eliminate costly hazardous waste and process effluent disposal by recovering nearly 100 per cent of valuable chemical resources and water for immediate reuse. Furthermore, CAST III can concentrate mixed hazardous wastes to 1-3 per cent of its original volume for economical HAZMAT disposal. CAST systems, which are based on the most advanced technology available, are unique in the wastewater recovery industry. Typical applications include reclaiming precious metals, zero-discharge wastewater recycle/reuse, direct replacement of atmospheric/vacuum evaporators, recycling of chemical resources, and upgrading IX and RO/UF partial recovery units to zero-discharge.

Standard or tailor-made units can be supplied, depending on the requirement. CAST systems are manufactured using corrosion-resistant metal alloys and engineering plastics, and designed to work in harsh industrial environments. The units are suitable for treating concentrated effluents, corrosive materials, high solids solutions, foaming liquids and media that foul or attack atmospheric evaporators, and ion exchange systems and membrane systems. 

Contact: CASTion Corp., 290 Moody Street, Ludlow, MA 01056-1244, United States of America. Tel: +1 (413) 5891 601; Fax: +1 (413) 5897 301.


Aerobic biological processing

Environmental Group Ltd. (EGL) of Australia is using a novel aerobic biological processing technique for processing difficult-to-treat effluent streams, e.g. wastewater from pulp and paper industries. The Natrix method, developed by Anox, is a suspended carrier biofilm process based on the use of plastic carrier media, which are kept in continuous movement. Effluent is fed to the reactor where micro-organisms available as a biofilm upon the surfaces of the carrier media decompose the organic matter in wastewater, thus removing COD, BOD and toxicity. A major part of the organic matter is converted into carbon dioxide and water, while a minor part yields biomass. Excess biomass sloughs off from the media and is washed out of the process along with the treated effluent.

Oxygen necessary to aid the micro-organisms in decomposing organic matter is supplied by blowing air through a coarse bubble aeration grid at the bottom of the reactor. As such, contents in the reactor are mixed and the carrier media is kept in motion. Treated effluent exits the reactor through a screen, which retains the carrier media. Available in five models, the patented Natrix carriers are injection moulded from high-density calcium carbonate and polyethylene. Two C-models each measure 31 mm, have a diameter of 31/35 mm and contain either 12 or 20 plates. Each of the two M-models have a length of 50 mm, a diameter of 52/64 mm and contain either 12 or 24 plates. Model O has a length of 50 mm, a diameter of 60 mm and contains 24 plates. A cubic metre of Natrix contains nearly 25,000 units of the C model, 5,000 of the M model and 4,500 of the O model. The filling volume is typically 30-65 per cent of reactor volume. The systems are designed to treat specific soluble COD loads.

The robust Natrix system provides efficient, stable and reliable treatment. It is one of the most compact biological technique presently available. 

Contact: Mr. Simon Cobden, Business Development Manager, Environmental Group Limited, 9, Packard Avenue, Castle Hill 2154, Australia. Tel: +61 (2) 9899 3499; Fax: +61 (2) 9899 3463



Multi-plate reactor

SNC Research Corp., Canada, is offering multi-plate reactor process for treating industrial effluents with very high concentrations of organic matter typically wastewaters from chemical and agro industries and paper mills. Organic matter is partly converted into methane by employing an anaerobic biological process. Gaseous emissions are collected at the reactor outlet, to be burned or to provide energy.

Water is pumped from the bottom to the top of the vertical reactor, with plates at three levels. These plates are connected such that upward flow of liquids and some of the gases is allowed while holding back bacteria from falling to the base of the reactor. The plates serve to distribute the load and allow gases to be produced over several sludge beds. Turbulence that would otherwise cause movement of the biomass towards the reactor outlet is minimized. An additional benefit of this technique is its compactness 60 m2 of floor space can house a system with a capacity to handle 500 kg/d of chemical oxygen demand (COD). Alternating treat-ment of different types of effluent is also feasible.

The multi-plate reactor process is suitable for readily biodegradable organic matter that is non-toxic for the systems bacteria. It can handle organic loads of 2,000-60,000 mg/l COD; the upper limit of reactor productivity is 30 kg COD/m3/d. While the reactor retention time varies from 12 to 40 hours, gas production yields up to 20 m3/d are feasible. 

Contact: SNR Research Corporation, Place Flix-Martin, 455, Ren Lvesque Ouest, Montral, Qubec H2Z 1Z3, Canada. Tel: +1 (514) 8666 635; Fax: +1 (514) 8660 600; 

Website: or 

Treatment of landfill leachate and hazardous wastes

Pall Corp., the United States, offers filtration and separation systems for removing micro-organisms, metals, arsenides, radioactive particles and chemicals from landfill leachate and toxic wastes. These new-generation filtration units can transform wastewater into a valuable resource by purifying landfill leachates for reuse and reclaim effluent from municipal wastewater facilities. The most economical and environmentally benign process to treat landfill leachate is to reduce its volume by 75-80 per cent using reverse osmosis and then return the concentrate to the landfill through controlled re-injection.

The patented Reverse Osmosis Disc Tube (DT) technology can ensure significantly improved performance through its flow path design, the use of high pressure in the vessel and a self-cleaning system. It removes inorganic and organic contaminants, including heavy metals. Hazardous substances are reduced to very low levels that have been stipulated by the most stringent regulatory criteria. Highly contaminated feedwater can be processed without the need for extensive pre-conditioning. For processing landfill leachate, a coarse sand filter is used to pretreat influent waters, which may contain 10,000 ppm dissolved solids and 5,000 ppm suspended solids. Over 90 per cent of leachate volume can be recovered as clean water (permeate). Other benefits of the DT system include:
  • Minimization of membrane fouling and scaling
  • Long membrane life
  • Lower membrane replacement costs
  • Easy access to all membranes
  • Unattended operation and
  • Compactness and flexibility.

Contact: Pall Corp., 25, Harbour Park Drive, Port Washington, NY 11050, United States of America. Tel: +1 (516) 4843 600; Fax: +1 (516) 4843 651.


New technique for segregating heavy metals

Romar Technologies of the United States develops new processes and chemistries to remove heavy metals present in industrial wastewater. The Recovery Of Metals and Recycling (ROMAR) process is an innovative and effective chemical method to remove and reclaim copper, tin, lead as well as other heavy metals from chelated wastewater and concentrated etching/plating wastes. In this procedure, metal hydroxide sludge from the clarifier is recycled and converted into a useful reagent to treat chelated wastewater. Thus, sludge disposal costs and liability are reduced dramatically. The ROMAR process is an inherently safe and eco-friendly technology that uses only non-hazardous dry chemicals. Benefits offered by this technique include:
  • Clean and clear effluent stream;
  • Reduced hazardous waste disposal cost and liability
  • High recycling value for recovered materials;
  • Safe, simple and reliable operation; and
  • Easy integration into an existing wastewater system.

The Metalex process is a new batch treatment method for spent photo resist strippers and developers. This unique two-part process detacifies precipitated photo resist solids and takes out the metals. It has proved to be very effective on many different types of aqueous and semi-aqueous strippers. The precipitated solids are easily dewatered in a standard filter press. Solids content of the press cake being as high as 40 per cent is common. This procedure utilizes Metalex PRC for detacification and Metalex MRC for complete removal of copper and lead. Benefits of this process include simple batch technology, produces clean and clear filtrate, complete metals removal, very low sludge volume, easy-to-use liquid products and excellent release from press.

E-Z Treat procedure is specifically designed to treat spent electroless copper baths and many other EDTA-based solutions, e.g. black oxide post-dip chemistries. It works at an alkaline pH and gives only elemental metals as sludge. The process is carried out in a simple batch reactor with mechanical agitation. 

Contact: Romar Technologies, 94, Central Street, Topsfield, MA 01983, United States of America. Tel: +1 (978) 8870 777; Fax: +1 (978) 8870 111.

Sludge processing

Premier Wastewater International, the United States, offers Enhanced Solids Reduction (ESR) system for processing and disposing sludge. This wastewater treatment system is an advanced activated sludge process that reduces organic sludge by up to 90 per cent. This is achieved by conditioning the waste stream, oxygenating and altering its state to greatly enhance the efficiency of the natural biological processes that are responsible for stabilization and removal of unwanted constituents.

At the core of the ESR process is the proprietary Multi-Action Conditioner (MAC) system that combines a superior aeration procedure with aggressive coalescing of the waste streams components. Through the effective use of hydraulics, the MAC system violently blends atmospheric air and mixed liquor under pressure generating micro-bubbles, shearing and selective cavitation. Complex associated forces fractionalize the particulates and shear large oxygen bubbles into micro- and micron-sized bubbles, thus making nutrients and oxygen more available to microbes. Additionally, under normal conditions an oxygen concentration gradient in floc makes it aerobic on the outside but anaerobic towards the centre. With MAC, the micro- and micron-sized bubbles become entrained inside the floc, thus keeping it totally aerobic over time. The entire waste stream is merged to achieve a relatively uniform biota consistency. One of the primary benefits of the ESR process is cost savings. 

Contact: Mr. Matt Russell, Premier Wastewater International, United States of America. Tel: +1 (702) 7390 909




Bacteria help recover precious metals

At the University of Birmingham in the United Kingdom, a group has filed an application to patent a new process in which micro-organisms recover valuable compounds more quickly and cheaply than traditional methods. In the automotive industry, this technology could help overcome future shortages and higher prices of platinum group metals (PGM) as demand outstrips supply. The technology integrates metal removal from exhausted automotive catalysts and PGM recovery in a simple process.

A key breakthrough in the development of this technology is a type of electrochemical cell known as an electrobioreactor, towards which the patent application has been filed. It resembles a hollow pencil, whose outer casing supports the bacteria. When the pencil is immersed in a continuous flow of waste, metal is deposited on to the cell walls of the bacteria. If left to build up, the deposits will drop off to the bottom of the vessel from where it can be recovered. This procedure requires about 15 minutes under typical operating conditions to continuously remove PGMs with approximately 90 per cent efficiency.


Recovering hydrogen and sulphur from refinery wastes

In the United States, researchers at Argonne National Laboratory are developing a new process that employs microwave plasma chemistry to split hydrogen sulphide. Microwave-Induced Sulphur and Hydrogen Autolysis (MISHA) technique can recover hydrogen and sulphur from hydrogen sulphide, thus facilitating hydrogen recycling. MISHA is ideal for refineries as it can replace both old Claus and tail-gas clean-up units while lowering costly on-site hydrogen synthesis. In some cases, the patented MISHA system can even replace the amine purification unit, enabling further savings.

In order to achieve hydrogen sulphide conversion and low energy usage, two reactor conditions have to be satisfied. First, microwave energy must be transferred efficiently to the plasma to create a high-temperature zone. Secondly, the fluid dynamics within the plasma-chemical reactor must isolate and stabilize plasma as well as, simultaneously, rapidly separate and cool the products. This freezes products at a composition which is characterized by plasma temperature rather than the bulk gas temperature. To satisfy these reactor conditions, the feed is injected tangentially into the reactor, above the central plasma zone. This creates a turbulent cyclonic flow that prevents plasma from contacting the reactor wall, thus minimizing energy losses. It also creates a thin, turbulent, high-temperature layer over the plasma surface, where hydrogen sulphide rapidly dissociates. The turbulence of this boundary layer ensures that the dissociation products are rapidly quenched as they remix with bulk gas flowing around the plasma.

Furthermore, sulphur reacts with itself to form high molecular weight clusters that are driven to the wall of the reactor by centrifugal forces generated during the cyclonic flow. This prevents sulphur from re-entering the turbulent boundary layer and back-reacting. Experiments at the Argonne National Laboratory have shown that:
  • MISHA recovers both hydrogen and sulphur at low costs while saving energy and oil;
  • Hydrogen sulphide emissions would be minuscule, less than 10 t/y, for a facility recovering 158 t/d of sulphur and 3.9 million scf/d of hydrogen; and
  • In some locations, MISHA could easily be used to recover marketable hydrogen from natural gas production operations.


Turning wastes into resources

In Canada, the Pildysh Group has developed Terra-Bond technology to convert unwanted wastes and by-products into a valuable resource. The patented method uses various industrial wastes as a feedstock in the production of synthetic aggregate (gravel), known as J-Gravel, that can be incorporated into high-quality asphalt paving material known as Terra-Mix for use in road construction. Bench-scale tests of the Terra-Bond process have demonstrated that industrial wastes suitable for conversion into synthetic aggregate include sulphur, fly-ash, bottom-ash, slag, electrostatic precipitator dust, petroleum coke, phospho-gypsum, contaminated soil, oil field sludge, drilling muds (invert) and cuttings. Contaminants that can be encapsulated include arsenic, chlorides, hydrocarbons and pesticides. Terra-Bond enables substantial reduction in costs associated with waste and by-product management by creating value-added construction products, developing new lines of business and eliminating liability.

J-Gravel is a high-quality synthetic aggregate for use in hot and cold asphalt paving mixes. It is far more cost-effective than asphalt incorporating traditional natural aggregates and 20-30 per cent lighter, thereby immensely reducing transportation, mixing and placing costs. The environmentally safe and friendly aggregate can be manufactured utilizing recyclable feedstocks. It exhibits a very high natural affinity to oil-based binders. Terra-Mix is a high-quality synthetic cold asphalt paving mix produced from the synthetic J-Gravel aggregate. 

Contact: Pildysh Technologies Inc., 288, 200 Rivercrest Drive S.E., Calgary, Alberta, T2C 2X5, Canada. Tel: +1 (403) 7206 699; Fax: +1 (403) 7206 609



Contaminated material recycling 

OnSite Technology LLC, the United States, is offering a breakthrough technology to clean-up and recycle contaminated materials. The new patented Indirect Thermal Desorption (ITD) series 6000 system uses indirect thermal desorption for separating and recycling hydrocarbons and other contaminants from various media. The cost-efficient, portable unit utilizes a rotating, heat jacketed closed barrel for vaporizing organic components from the contaminated material. Hydrocarbon vapours are captured by employing condensers. ITD helps eliminate the problem of disposing contaminated soil in the energy industry and enterprises producing hydrocarbon contaminated soil, oily wastes, drill cuttings and industrial hazardous waste. In the ITD technique, heat applied to the stained material raises the contents temperature above the pollutants vapour point. Contaminate vapour is removed through condensing and recovered for reuse. Soils polluted with gasoline, diesel, lubricant oil, crude oil, as well as oil-based drilling mud have been treated successfully.

The contaminated materials can be delivered to the ITD system through a loader, vacuum or conveyor belt. Material deposited into a feed auger enters the sealed negative-pressure, externally heated, rotating drum. The drum is configured with a series of lifters and scrapers that agitate and aerate the material. The material is heated and degassed as it travels the length of the drum and exits at a constant temperature through a series of airtight doors and chute to an enclosed auger for rehydration. The material is tested and conveyed to the disposal site. Hydrocarbon and water vapours are removed from the drum by means of vacuum and condensed for recovery and recycling. Process and retention time of the materials in the heated chamber of the system depends on the feed rate, speed, rotation and slope angle (rake) of the rotary drum. Key factors in determining the optimum retention time include contaminant levels, moisture content, soil type and compliance goals. Appropriate retention times are maintained by adjusting the drum rotation or drum inclination. 

Contact: OnSite Technology LLC, 2600, South Loop West, Ste. 645, Houston, Texas 77054, United States of America. Tel: +1 (713) 6413 838; Fax: +1 (713) 6410 756; 



Treating chlorinated hydrocarbon wastes

Nittetsu Chemical Engineering Ltd., Japan, is offering a new method to recover hydrochloric (HCl) acid. In the waste heat boiler (WHB) technique, waste liquid containing organic material is incinerated to generate steam through waste heat recovery. It concurrently reclaims high purity hydrochloric acid. As such, this incineration system is the most reliable and economical means to dispose chlorinated hydrocarbon wastes. The WHB technique offers the following benefits over conventional quenching systems: easing service condition of the absorption tower for materials by lowered temperatures at the HCl absorption tower. Another merit is decreased steam in the combustion gases, which means reduction of steam plume when discharged into the atmosphere. Any required concentration of recovered HCl can be obtained, ranging from a dilute one to even an anhydrous one.

Contact: Mr. T. Higashino, Nittetsu Chemical Engineering Ltd., 4-4-26, Funado Itabashi-ku, Tokyo 174 0041, Japan. Tel: +81 (3) 5399 3513; Fax: +81 (3) 5399 3758



Off-site disposal of refinery and petro-chemical plant sludge

Scaltech Inc., the United States, is offering Scalfuel process that converts oily waste solids into a liquid fuel that is suitable for recycling in cement kilns approved to recycle hazardous waste-derived fuels. The stable pumpable slurry is tailored to meet the viscosity, water content and BTU value requirements for kiln recycling. It contains more than 40 per cent solids, less than 10 per cent water and can be moved in standard tank trucks or by rail.

In the Scalfuel process, solids are first separated from oil and water using either high-speed vertical disk centrifuge or conventional horizontal decanter, depending on the needs of the plant. The resulting solids are mixed with the correct proportion of oil in a proprietary high-energy mix tank. The slurry is then fed into a liquids/slurry drier where water is evaporated. Oil and water effluent from the centrifuge are returned to the facilitys wastewater treatment system.

Contact: Scaltech Inc., 87, Oates Road, Building 1, Houston, Texas, TX 77013, United States of America. Tel: +1 (713) 6728 004; Fax: +1 (713) 6728 209




Asphalt plant dust collection system

DISA Airmaster Engineering Limited, the United Kingdom, has supplied a specialized dust collection system to an asphalt production facility with a capacity of 70-80 t/h. The new dust collection system uses DISA down-flow, reverse-air cleaned, cassette-type filter unit for controlling dust emitted from various points in the production process, including the drier, mixer, elevator, screens, silos and chutes. A pre-separator skimmer is integrated to remove large dust particles (above 75 microns) for reprocessing. Collected dust is cleaned from the filter bags by the off-line effect reverse-air cleaning system and deposited into the filter hopper, from where it is returned to the mixer through a rotary valve and conveying system. Clean air is ducted from the filter to the main fan and then discharged into the atmosphere by way of a free-standing exhaust stack. The emission level presently achieved is less than 5 mg/m3. 

Contact: DISA Airmaster Engineering Ltd., Limewood Approach, Seacroft, Leeds LS14 1NG, United Kingdom. Tel: +44 (0113) 2739 400; Fax: +44 (0113) 2650 735; 



Screw-type electro-static precipitator

Bo-Yang Mechanical Engineering Co. Ltd., the Republic of Korea, is offering new systems for removing dust from combustion gas at very high temperature and pressure. A screw-type electrostatic precipitator (STEP) and electro-cyclone are utilized in conjunction with a general multi-cyclone to collect large dust particles. The tube-type STEP requires less space than plate-type ESP of the same gas volume. A key benefit of STEP is that particles in the exhaust gas migrate under the influence of centrifugal force, which is generated by the screw-type discharge electrode, as well as a strong electric field.

The electro-cyclone is an adaptation of a conventional cyclone in which high voltage is generated inside the cyclone. It incorporates a clean air shield adjacent to the exhaust duct, thereby preventing short-circuiting of dust into the outlet. Clean air is provided by an axial flow separator/electrostatic charger device that is positioned in the exhaust duct of an upstream cyclone. In the electro-cyclone, dust separation is strongly augmented by another high-voltage field applied with an electrode along the axis of the cyclone. Electrodes are formatted as barbed electrode that is fabricated using steel strips welded on barbs whose length varies as per the spacing and the gas to be treated.

The multi-cyclone can remove large dust particulates from combustion boilers at high pressure and temperature, and fly-ash from cement mills. Identical cells are placed in parallel above a hopper. At the inlet of each cell are fitted internal vanes (or guide vanes) to impart a spinning motion for the dust-laden gas. Centrifugal force drives dust to the outside of the cell where it falls freely into the hopper, while cleaned gas emerges from the cell through the central pipe. 

Contact: Bo-Yang Mechanical Engineering Co. Ltd., 495-10, Jinkwannae-Dong, Eunpyung-Gu, Seoul 122 943, the Republic of Korea. Tel: +82 (2) 3556 986; Fax: +82 (2) 3527 424



Degrading VOCs

MEGTEC Systems, Singapore, is offering flexible designs and field-tested, proprietary catalyst formulations to convert VOCs into carbon dioxide and water. Magnum uses an efficient line burner and maintenance-free exterior to deliver years of dependable operation, ensuring VOC emissions are below 20 mg/Nm3. The systems high-efficiency line burner ensures uniform temperature distribution of the air entering the catalyst beds. A stainless steel plate-type heat exchanger maximizes operating efficiency and minimizes fuel costs. Thermal energy is extracted from purified exhaust after it leaves the catalyst beds. PLCs provide operating status data, first-out troubleshooting indications and a maintenance schedule.

Quantum is designed specifically for industrial operations with exhaust flows of less than 5,000 SCFM. It uses the most cost-effective catalyst available, achieving up to 98 per cent VOC destruction at temperatures lower than that required by conventional thermal oxidizers. Advanced controls automatically maintain high VOC destruction rates, provide the maximum efficiency and protect the system from thermal stress. A low-maintenance gas-fired burner provides efficient combustion. This unit saves fuel costs by using thermal energy from the exhaust to preheat incoming process air. The stainless steel plate-type heat exchanger is available with an efficiency rating of about 70 per cent. 

Contact: MEGTEC Systems, Singapore. Tel: +65 2984 666; Fax: +65 2946 222.



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