VATIS Update Waste Management . May-Jun 2008

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Waste Management May-Jun 2008

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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Green collection centres for e-waste mooted in India

The new guidelines on e-waste from the Central Pollution Control Board of India suggest setting up, based on the Swiss model, “green collection centres” for the collection and dumping of e-waste in environment-friendly manner. The guidelines say that “The producers shall take the responsibility of collection of the end-of-use equipment through facilitating the establishment of a common collection point and suitable storage infrastructure.” The cost of setting up these centres would be met by imposing an appropriate fee on the product at the point of sale, facilitating the operation of the buy-back system and providing standardized rates to the customers.

These guidelines shall apply to all those who handle e-waste, which includes the generators, collectors, transporters, dismantlers, recyclers and stakeholders of e-wastes. They also ensure establishment of an e-waste recycling and treatment facility in line with the existing requirements for setting up and operating recycling and treatment and disposal facilities for hazardous wastes. “Such facilities shall be set up in the organized sector,” a senior government official said. He added that the objective of these guidelines is to provide guidance for identification of various sources of waste in electrical and electronic equipment and prescribe procedures for handling e-waste in a more environment-friendly manner.

A study estimated the e-waste inventory for 2005 as 146,180 tonnes, which is expected to grow to more than 800,000 tonnes by 2012. India has no large-scale organized facility for e-waste recycling.


Waste separation programme clicks in Hong Kong

In Hong Kong, about 350 buildings have joined the Source Separation Programme of Commercial and In-dustrial Waste. Commercial and government office buildings, shopping arcades, industrial buildings, warehouses and car parks feature among them. The project, launched in October 2007, recruits commercial, industrial as well as government buildings for installing mechanisms for “source separation” that enable tenants to partake in waste recovery and recycling.

Opening the Forum on Source Separation of Commercial & Industrial Waste, Permanent Secretary for the Environment Ms. Anissa Wong said, “Although recovery for commercial and industrial waste has been maintained at a relatively high level of 60 per cent over the years, sustained economic growth is starting to induce a rise in the generation and disposal of commercial and industrial waste.” To help the public and property management understand the programme more, the Environmental Protection Department has launched a new website.


Viet Nam plans for clean industry

By the year 2020, Viet Nam aims to create industries that can handle the growing need to protect the environment from the impact of surging national development. According to a scheme to be put to the government in the third quarter of this year by the Ministry of Trade & Industry, the standardization of environmental services for the nation’s many regions would be a top priority. The Ministry said that there is an urgent need to set up an environment protection industry in a period of high economic growth.

The Ministry described the environment industry as a grouping of producers of environmental products and services that measure, limit, prevent, minimize or regulate environmental damage to water, air or land, and those that relate to waste, noise and the ecology. The industry is tasked to provide cleaner technologies and products, pollution management services, as well as resource management.

A recent national seminar on the establishment of Viet Nam’s environmental development agreed the nation had the basics for an environment protection industry, including high demand, a diversified market and the existence of a few environment companies. Statistics show that about 65 per cent of industrial wastewater from the garment industry is not properly treated, and about 90 per cent of almost 500 paper producing enterprises either have no wastewater treatment or have sub-standard ones. In the chemical industry, only 50 out of 901 enterprises have wastewater treatment units. Most villages do not have any separate systems to collect and treat solid waste, much of which is dangerous.


Nationwide waste-management project in Sri Lanka

A new waste management project will be soon introduced throughout the country by the Ministry of Environment and Natural Resources, Sri Lanka’s Minister Mr. Champika Ranawaka has said. The project, Pilisaru, aims to build the capacity of local government authorities with enhanced methodologies to serve in large-scale garbage management processes. A workshop was recently organized to educate the local government authorities of Gampaha and Colombo districts about the new waste management project. The Minister apprised the authorities of the necessity of implementing such a mechanism to overcome the garbage problem that is emerging both in urban and suburban areas.

The Central Environment Authority is set to spend Rs 1 billion for 2008. It has identified sites to establish necessary landfills, said the director general of the Authority, Mr. Pasan Gunasena. “Composting and recycling are components of the overall programme; only the residue after composting of garbage can be directed to the landfills under this Pilisaru programme,” he said. The programme is a national approach for solid waste management in Sri Lanka. Although solid waste management is an obligatory function of the local government institutions, its implementation is currently poor, resulting in numerous environmental, health and sanitation problems.


Pollution census launched in China

A comprehensive census of pollution sources involving a 30,000-member task force was launched in Henan province, China, recently to help better address Henan’s environmental issues. According to Mr. Wang Guoping, director of Henan Provincial Environmental Protection Bureau and head of the province’s pollution source census office, the large-scale campaign is a response to the first nationwide survey encouraged by the country’s environmental watchdog on tracing the sources of industrial, agricultural and residential pollution.

“The result of the survey will be serving as basic data to analyse the distribution of pollution in different industries and places,” Mr. Wang said. “It will provide evidence for mulling more effective pollution control measures.” Preparation work found that Henan has more than 240,000 sites of pollution sources including 54,000 industrial, 63,000 residential and 125,000 agricultural sources. Residential pollution is said to be the most severe source in the province at present. It comprises kitchen trash, recycled paper, glass, metal, plastic, hazardous trash and sewage.

A large agricultural province, Henan suffers from a high usage of fertilizer, pesticide and a large amount of animal waste. By 2007, the province had taken a lead in launching sewage plants in all 108 counties and 18 cities, thus greatly enlarging the industrial treatment capacity.


Plastic-to-energy idea wins backing in Thailand

Thailand’s Energy Ministry is promoting the processing of plastic waste into oil as part of a plan to reduce the country’s oil imports as well as to reduce pressure on the environment. Energy Minister Lt. Gen. Poonpirom Liptapanlop announced two guidelines to support a project to convert plastic waste into oil.

According to the plan, the Energy Conservation Fund will provide loans worth Tk 105 million (US$1.5 million), from which each R&D and pilot project will receive funding under Tk 35 million (US$0.51 million). The second support mechanism is the price. The Ministry will use money from the Oil Fund to subsidize oil made of plastic waste and agree to provide investors Tk 7 (US$0.10) per litre for waste-based oil production for five years.

The amount of waste generated in Thailand is estimated to be 40,000 tonnes per day and after treatment 30 per cent of the plastic waste still remains. According to research, the minister said, the oil made of plastic waste could offer properties almost similar to crude oil. She added that Thailand is yet to seriously adopt the process of converting plastic waste into energy but only conducted research in the area.


Tie-up for waste management in Asia

Indah Water Konsortium Sdn Bhd (IWK) of Malaysia and Environment Cooperation-Asia (Eco-Asia) are collaborating to promote sustainable management of sewerage and wastewater in Asia. “The role of Eco-Asia is to provide the coordination and financial support for us to reach out to other sewerage and wastewater operators that need our help,” said Mr. Suhaimi Kamaralzaman, IWK director.

In the collaboration, IWK will share best industry practices and innovation to improve sanitation service delivery, serve as the regional training centre, provide technical support and also develop toolkit for septage. Eco-Asia would be a “matchmaker” in the arrangement with IWK to provide the linkages to other sanitation service operators in the region, said its deputy chief of party Mr. Niels van Dijk. Eco-Asia, a regional environmental programme of the United States Agency for International Development, works with wastewater and water service providers to enable improved access to safe water and sanitation for urban residents.



Innovative process recycles waste EPS

Historically, clean post-industrial and consumer packaging made of encapsulated polystyrene (EPS) was not recycled since the cost-benefit ratio of the available processes was low. Typically, equipment designed to handle EPS is either too expensive, or so large and cumbersome, that most companies or municipal recycling programmes find it is not feasible for them. RecycleTech Inc., the United States, has changed that by creating a line of polystyrene processing equipment with just a 4 ft × 4 ft footprint (XT200).

The machines from RecycleTech use heat to reduce the size of the material by about 90 per cent, melting and compressing it into a solid plastic ingot. This ingot is used as the raw material for other plastic products such as picture frames or CD jewel cases. The patent pending line of equipment from RecycleTech thus processes polystyrene and other plastics into a condensed recyclable form. Contact: Mr. Leonard Black, RecycleTech Inc., 1010 Hoyt Avenue, Ridgefield, NJ 201-943-7142, United States of America. Tel: +1 (201) 943 7142; Fax: +1 (201) 943 6928; E-mail: len@recycletechno. com.


Closed-loop recycling for reduced waste

A new closed-loop, customized pro-cessing service that recycles post-industrial packaging strapping scrap into reusable polymer is helping a British processor to reduce landfill and save raw material. Developed by the compounding division of Luxus Ltd. for Plastic Extruders Ltd., a processor of polypropylene strapping for the packaging industry, the process uses melt-reclamation technology. The strapping is extruded from homopolymer polypropylene with a special stabilization package that helps reduce moisture intake.

Plastic Extruder sends baled strapping waste to Luxus, which then processes it into a recyclate of set specifications. Key to the success of converting the waste polypropylene into reusable material is the Luxus technical centre where the feedstock is evaluated and a suitable compound is developed.

The strapping material is checked for any contamination and then processed on an Erema melt reclaim line. At this stage, any volatiles or moisture are driven off and, if required, any additive or master-batch dosed into the melt to produce the desired physical characteristics. Following pelletization, the material undergoes melt flow and tensile tests. On completion of compounding, each batch of the self-coloured material is blended for achieving colour consistency.


Technique for recycling mixed plastics

A technique that can process mixed plastics and create new recyclable products may help companies cut the high cost of sorting waste. Environmental Recycling Technologies (ERT), the United Kingdom, is using its powder impression moulding process to develop products such as building site fencing systems and reusable plastic containers. ERT’s process can handle a wide range of plastics, from the most common family of packaging polymers – olefinic materials – to recycled polystyrene. Olefinic polymers include polypropylenes (such as shampoo bottles) and polyethylene (such as cling film, plastic bags, as well as milk bottles).

In the process, an external heat is applied to the mould set, in which skin layers of mixed-plastic granules (or single plastic, depending on product specifications) are laid to form the exterior skin of the product. After that, a core of powdered mixed-plastic, which also contains a small amount of chemical blowing agent, is put into the mould. Closed moulds are set together, and the temperature increased to melt the plastics within the skin and the core, and to decompose the chemical blowing agent. The resulting plastic product has a foamed core of much lower density than typical thermoplastics, and yet has a solid outer layer.

The process can be adapted, depending on the availability of raw materials product specification. For example, if a product needs to be lightweight and cheap, a suitable raw material would be something like recycled polyethylene. In certain circumstances, other materials could be blended with the polymer waste streams during the process or just prior to it, to achieve desired material properties. Other non-polymer materials, such as fibrous or metallic reinforcements, may be introduced into the core.


New plastic waste recycling plant

Intercontinental Recycling Ltd., the United Kingdom, has reported that its new plastics recycling facility has successfully undergone operational trials. The plant, supplied by Wilson Recycling Machinery Ltd., can process 30,000 tonnes a year of PET and HDPE plastic bottles into various polymers for use in the sheeting and packaging industries, using a separate sorting-washing plant.

At the new plant in Skelmersdale, a feeder and conveyor lead to a sorting house where large contaminants are removed. The material is then passed through magnetic and eddy current separators to recover metals. The remaining material is transferred to a Stadler STT 2000 twin-deck ballistic separator, which sorts plastic bottles through the manner they bounce from contaminants such as paper, card, film and glass. After this, bottles are washed and granulated into the final product. The plant consists of two processing lines, which deliver about 2 tonnes of clean, recycled polymer per hour. Contact: Wilson Recycling Machinery Ltd., The Coach House, Front Street, Earsdon, Whitley Bay, Tyne & Wear, NE25 9JT, United Kingdom. Tel: +44 (191) 253 1402; Fax: +44 (191) 251 5994; E-mail: info@



Plastics granulators

Rapid Granulator AB of Sweden has introduced a new series of “open hearted” granulators for waste plastics. Available in three models, the Rapid 600 series can handle up to 2,500 kg of material per hour. Rapid’s open-heart concept is based on an ergonomic design that provides fast, direct and complete access to the heart of the machine, the rotor and the cutter house during production changes. According to the manufacturer, this radically simplifies inspection, cleaning and maintenance processes, which can account for up to 80 per cent of a granulator’s running costs.

The new 600 series machine can be 900, 1200 or 1500 mm wide and comes with a choice of five motors, and three, five or seven blades. It also has a mineral composite base that is claimed to reduce noise and vibration. Rapid also offers 300, 400 and 500 series open-hearted granulators. The 400 series has been expanded to include the 400-60 HD for tough applications, and the 400-120 for extra-wide injection moulded and thermoformed wastes.

The Rapid open-hearted granulators are designed for high-volume central or beside-the-press granulation of injection-moulded, blow-moulded or extruded plastic waste or rejects for direct recycling. All employ the Rapid cutting technique, comprising a clean double-scissors cutting action and a constant cutting circle for producing granules of uniform size. Contact: Rapid Granulator AB, Box 9, Industrivägen 4, SE 330-10 Bredaryd, Sweden. Tel: +46 (370) 86500; Fax: +46 (370) 80251; E-mail:


Mixed plastics recycling plants

Plastics recycling plants from Italy’s Longinotti Recycling transform heterogeneous rigid and flexible plastic wastes – of industrial, agricultural or household origin – generally without particular sorting or washing into quality end products. The wastes, baled or loose, are shredded and conveyed to a granulator (for rigid) or densifier (for flexible).

The granulated/densified waste is sent to the mixing silos for thorough blending. The blend is then introduced into special extruders where a homogeneous paste is produced without causing any degradation of the material. The extruder has a highly efficient length/diameter ratio that allows a rapid extruding phase for consistent quality of the plastic paste. It feeds the material into a set of low-pressure, water-cooled moulds, assembled like a revolving drum, revolving table or horizontal line. After the cooling phase, the end product is ejected.

LER 7.0 is a fully automatic plant with a new high-performance recycler, with maximum output of 900 kg/h, for the low pressure moulding of pallets and other large-sized products. The moulds, made of special aluminium alloy, are set on a revolving table and water-cooled. Contact: Longinotti Recycling, Via Prov. Lucchese 201, 50019 Sesto Fiorentino, Italy. Tel: +39 (55) 302 321; Fax: +39 (55) 341 120; E-mail: info@recyc




Feedstock recycling from the PCBs of used computers

Joint research by scientists from the Petru Poni Institute of Macromolecular Chemistry, Romania, and Ege University, Turkey, has found that catalytic cracking and dehalogenation procedures are effective and yet simple methods to convert printed circuit boards (PCBs) into some useful products. The researchers focused on the pyrolysis of PCBs from used computers using various combined procedures of thermal and catalytic pyrolysis and dehalogenation (absorption) aiming to obtain pyrolysis oils with low amounts of heteroatoms (nitrogen, bromine, chlorine and oxygen) that might be suitable for use as feedstock or fuel. The composition of degradation oils was determined by suitable methods, such as gas chromatography (GC-MSD and GC-AED), H nuclear magnetic resonance, and Fourier transform infrared spectroscopy, and common methods for the analysis of petrochemical products.



Solvent system reduces spent battery hazard

The boom in demand for portable electronic products such as mobile phones and laptop computers has put a premium on rechargeable lithium batteries. A typical lithium battery lasts for 300-500 recharges (around one to three years), after which point it is likely to end up in landfill and pose an environmental hazard. In addition to lithium contamination, metals such as iron, cobalt, aluminium and copper can leach from these spent batteries. In Australia, the Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions, together with CSIRO Minerals, has developed a new solvent extraction (SX) process for recovering cobalt and lithium from this spent battery leach solution.

According to Dr. Chu Yong Cheng, a researcher at CSIRO Minerals, it is possible to recover cobalt and lithium from spent battery leach solutions but separating them from impurities such as iron, aluminium and copper is complicated. Dr. Chu has discovered that synergistic or mixed SX systems have the greatest potential to separate and recover lithium and cobalt from spent battery leach solutions.


Pyrolysis to recycle printed circuit boards

Researchers from the University of Leeds, the United Kingdom, have studied the suitability of pyrolysis for separating the components of printed circuit boards (PCBs) and recovering materials for reuse. Dr. Paul Williams and Dr. William Hall noted that pyrolysis has been well studied for polymer recycling, where the products are gases, oils and char, which are useful as chemical feedstocks and fuels. In addition, glass fibre from reinforced polymers is easily separated out.

The duo collected PCBs and cut them into small pieces (1.5-2 cm2) to fit in a lab-scale fixed-bed reactor. After purging with nitrogen to remove all traces of oxygen, the materials were heated to 800°C, at 10°C/min, and held at this temperature for 135 min. The pyrolysis oils and gases were trapped in a series of condensers for later analysis. The organic gases were analysed by GC-FID chromatography, while nitrogen, carbon monoxide, carbon dioxide, oxygen and hydrogen were analysed using GC-TCD chromatography. Compounds present in the pyrolysis oils were identified by GC-MSD chromatography with electron ionization and quantified by GC-FID. Phosphorus-containing compounds in the oils were identified and quantified by GC-ECD chromatography. The char remaining in the reaction vessel was analysed for metals content by scanning electron microscopy, energy dispersive X-ray analysis and ICPMS.

The proportion of residue, oil and gas (weight per cent) was 60-82, 15-28.5 and 2.3-6.5, respectively, for PCBs from computers, televisions and cell phones. The gases comprised mainly carbon dioxide and carbon monoxide and hydrogen, together making up about 76-87 per cent of the total gases. Apart from very small amounts of chlorine and bromine, the remainder comprised C1-C4 alkanes and alkenes. These organic gases could be siphoned off to be used as a fuel for the pyrolysis process. The pyrolysis oils comprised a high proportion of phenol. Significant amounts of 4-isopropylphenol, 4-hydroxyphenol and bisphenol A were also found besides many other phenols, deriving from epoxy resins on the boards. These could be recovered for reuse as raw chemicals.

The solid char residue was easily and quickly separated by hand into glass fibre, an organic fraction and a metallic fraction. The major metal in the ash was copper (33 per cent of the ash) with smaller but significant proportions of calcium, barium, iron, nickel, zinc, aluminium, lead and silver. Very small amounts of gold and the toxic mercury and cadmium were also found in the ash. These metals could be recovered from the ash and individually separated but further processing would be required.



New way to reduce toxic industrial waste

In the Philippines, a group of scientists has introduced treatment technologies for the reduction and elimination of polychlorinated biphenyls (PCBs). Research by Dr. Susan Gallardo and colleagues at the De La Salle University-Manila involved start-up experimentation using selected catalysed photo-oxidation processes such as ultraviolet (UV) irradiation, UV–hydrogen peroxide and UV–titanium oxide systems.

The researchers took samples of PCB-contaminated soils and transformer oils from the Clark Special Economic Zone, an identified PCB hotspot. After comparative tests, the scientists found that the highest degradation of PCBs, at 92 per cent, can be obtained from 120 minutes at peroxide concentration. “Based from the results obtained, catalysed UV processes significantly degraded PCBs. Dechlorination must be the major mechanism occurring in the solution especially during the first few minutes of the reaction where a drastic drop in pH was observed and the highest percentage of degradation was achieved,” said Dr. Gallardo.


Polymerization of cyclodextrin polyurethanes

Removal of organic compounds from water remains a big challenge for municipalities and water authorities. Such organic compounds – which include polychlorinated biphenyls (PCBs), poly-aromatic hydrocarbons (PAHs), endocrine disrupting compounds (EDCs) and dioxins – pose serious health risks to humans and animals. Techniques such as the use of activated carbon or zeolites and reverse osmosis are at present being used to treat water before consumption. However, activated carbon fails to remove many organic pollutants at concentration levels of nanograms per litre. Zeolites show low affinity for organic compounds and reverse osmosis is currently too expensive for wider usage.

Insoluble cyclodextrin (â-CD) polyurethanes have demonstrated the ability to remove organic species from water at concentration levels of nanograms per litre. Nanotubes of carbon have also been reported to efficiently adsorb some organic molecules such as dioxins and polychlorinated dibenzo-furans. These nanotubes, however, are currently too expensive to be used on their own in water treatment. Scientists from the University of Johannesburg, South Africa, have succeeded in the use of cross-linked cyclodextrin polyurethanes co-polymerized with “functionalized” multi-walled nanotubes (MWNTs) of carbon as adsorbents for organic pollutants.

It has been shown that functionalization of the MWNTs with a mixture of nitric acid and sulphuric acid introduced carboxylic acid and hydroxyl groups onto the nanotube walls. These groups take part in the polymerization of the nanotubes with â-CD and the diisocyanate linkers. Furthermore, polymers containing nanotubes showed an increased adsorption capacity for trichloroethylene. These polymers, unlike granular activated carbon, can be fully recycled and still maintain high adsorption efficiency and retain the chemical properties. Contact: Dr. B.B. Mamba, University of Johannesburg, Department of Chemical Technology, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa.


Catalytic conversion of organic pollutants

Chlorinated benzene, particularly 1,2-dichlorobenzene (1,2-DCB), has been widely used as one of surrogate compounds of dioxin to find the suitable methods to control dioxin. However, the relationship between the catalytic activity of dioxin surrogate compound and dioxin has not been understood quite well. In the Republic of Korea, two researchers from the Centre for Environmental Technology Research, Korea Institute of Science and Technology (KIST), have studied the catalytic conversion of polychlorinated benzenes and dibenzo-p-dioxins using a vanadium-based catalyst.

The KIST scientists used a V2O5/TiO2 catalyst to compare catalytic activity of chlorinated benzenes and dibenzo-p-dioxins with low-chlorine content using the lab-scale system. They investigated the catalytic conversions of low-chlorinated dioxins [2-monochlorodibenzo-p-dioxin (2-MCDD) and 2,3-dichlorodibenzo-p-dioxin (2,3-DCDD)] and polychlorinated benzenes [1,2-DCB, 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB), pentachlorobenzene (PeCB) and hexachlorobenzene (HCB)] to understand quantitative relationship between dioxin and benzene with the chlorination level.

The catalytic decomposition of chlorinated aromatic compounds was as follows: 1,2-DCB  > 1,2,3,4-TeCB > 2-MCDD > PeCB = 2,3 DCDD > HCB. It is therefore reasonable that PeCB or HCB should be used as the dioxin surrogate compound instead of 1,2-DCB, write the scientists. The decomposition of 1,2-DCB was found to be dependent on the space velocity, while the effect of oxygen content on catalytic decomposition was negligible in the range of 5-20 per cent. Contact: Dr. Jongsoo Jurng, Centre for Environmental Technology Research, Korea Institute of Science and Technology, 39-1 Hawolgok, Seongbuk, Seoul 130-791, Republic of Korea. E-mail:


Method of removal of PAHs from a liquid

Hoogovens Groep B.V., the Netherlands, has obtained a European patent on a method of removal of polycyclic aromatic hydrocarbons (PAHs). The process removes PAHs from a liquid by subjecting a PAH-liquid mixture to pre-coat vacuum filtration to remove solid particles, which contain or carry PAHs, and/or a second liquid phase that contains the PAHs. The process of pre-coat vacuum filtration comprises:

• Applying a particulate pre-coat, comprising finely divided organic particles, to the exterior of a vacuum filter drum of a rotary vacuum filter;
•  Filtering the liquid mixture using the filter drum by partially immersing the rotating drum in mixture and applying reduced pressure at the interior of the drum; and
• Continuously or intermittently removing a surface layer of the pre-coat, thereby presenting fresh particles of the pre-coat to the mixture to be subsequently filtered.

The organic particles present in the pre-coat have a layer thickness in the range 30-200 mm. The immersion depth of the drum during filtering is more than 40 per cent of the drum diameter. The drum is rotated with its axis horizontal. The patent also describes a pre-coat layer build-up test to determine the suitability of the organic particulate material of plant or animal origin for use as pre-coat material.


Non-ionic surfactant solubilization of PAHs

In Japan, researchers from Kyoto University’s Department of Urban and Environmental Engineering and the Graduate School of Engineering have investigated the non-ionic surfactant solubilization of polycyclic aromatic hydrocarbons (PAHs). They studied the enhanced solubilization of phenanthrene and pyrene from bentonite in micellar solution of the non-ionic surfactants Brij-30 (lauryl ether) and Triton X-100 (polyoxyethylene octyl phenyl ether). Experiments in batch bentonite/aqueous system found the solubilization of pyrene from bentonite in surfactant solutions to be very low because of low water solubility and strong sorption onto bentonite of pyrene. The solubilization of phenanthrene increased at bulk surfactant concentrations greater than the critical micelle concentration of the surfactant, with Triton X-100 displaying a greater solubilization than Brij-30.


Apparatus for destruction of organic pollutants

A Canadian researcher, Mr. René J. Cornellier, has filed for patent on an invention for the destruction of persistent organic pollutants (POP) that are traditionally disposed of in landfills or destructed, leading to the release of harmful breakdown products into the atmosphere, the soil or the water table. The apparatus designed for use with POP-contaminated oil includes: a first heating combustion chamber for heating the oil to generate a toxic fluid using a burner; a rotating transition cylinder with a drying chamber into which the hot toxic fluid flows from the combustion chamber; a second heating destruction chamber downstream of the cylinder to further heat the toxic fluid to substantially convert it into an inert fluid. The rotating cylinder holds a desiccant material to dry the toxic fluid.

The apparatus, and its associated method, aims to remove 99.9999 per cent of the toxic organic pollutant. It is lightweight and mobile, and uses inexpensive recyclable desiccating materials. In the three-stage process, the contaminated oil is first burnt within a burner to vaporize the POP (such as polychlorinated biphenyl). The vaporized POP then passes through a second stage where it is dried along a drying path. As it travels the path, it is heated to cause substantial thermal breakdown. The third stage involves the use of a conventional burner for generating heat to destroy toxic gases emitted during the combustion and heating processes. The first heating chamber is maintained between 600ºC to 1000ºC, and typically at about 850ºC. For a relatively small mobile apparatus that fits on a trailer, the maximum capacity for the first burner is typically 2.5 MBTU/h. The apparatus can destruct large volumes of POP: typically the combustion capacity is 50 kg/hour or 1 tonne per day.



Solution to turn sewage sludge into something useful

China’s Zhongke Bolian Hi-tech Co. (ZB High-tech), is trying to turn sewage sludge into something useful. ZB High-tech’s solution is based on neutralizing toxic content in the sludge while retaining all nutritious elements – such as nitrogen and phosphorous – to turn it into a fertilizer for organic farming. The process involves three steps – making toxic metals passive, killing pathogens and controlling odour.

Traditional composting is based on open-air biological decomposition of the waste’s organic constituents. It usually requires large areas to heap up and remix sludge, which needs to be turned over from time to time to let oxygen in and keep down the odour. The process has disadvantages. As it is out in the open, rains can easily wash away the heap. Moreover, to make the heavy metals and bacteria passive, the sludge heap must be kept at a relatively high temperature for one week, preferably at 50º-60ºC. So, turning over the sludge is not helpful. Thus, composting the sludge to remove pollutants is inherently contradictory in the traditional method.

ZB High-tech’s process keeps the sludge in interior pools, with oxygen chambers built at the bottom of the pools to provide additional oxygen needed. This is claimed to be the world’s first technology based on static oxygen consumption. After the toxicity is removed, the sludge becomes an organic fertilizer. The technology is, however, not good for specialized industrial sewage, as the sludge produced tends to have too high a heavy metal content and is low on organic substances.


Anaerobic bio-treatment of textile dyes

Researchers at the Department of Civil Engineering, University of New Brunswick, Canada, have integrated two different concepts of anaerobic biotechnology – two-phase anaerobic treatment and anaerobic granular sludge bed technology – in the treatment of coloured wastewaters from textile industries. In their work, Dr. D. Bhattacharya and Dr. K.S. Singh employed four anaerobic reactors based on upflow anaerobic sludge blanket (UASB) technology as acid reactors and an expanded granular sludge bed (EGSB) reactor as methane reactor. A conventional single-phase anaerobic EGSB reactor was run in parallel to compare the performances of the two systems. The reactors were operated at different hydraulic retention times.

The results from the study, which spanned over a period of 400 days, indicated that the two-phase system produces a higher effluent quality of in terms of colour, COD and suspended solids than one-phase anaerobic treatment when operated under similar conditions. Alkalinity requirement of two-phase system was also lower than that of single-phase system. Contact: Department of Civil Engineering, University of New Brunswick, 17 Dineen Drive, Fredericton, NB, E3B 5A3, Canada. E-mail:


Ammonia recovery for wastewater treatment plants

ThermoEnergy Corporation (TEC), the United States, has released an independent engineering study that demonstrates the use of its Ammonia Recovery Process (ARP) as resulting in substantial reductions in carbon emissions for municipal and industrial wastewater treatment plants, as compared with conventional biological processes for the treatment and removal of nitrogen/ammonia. The report shows that a generic 380 million litres per day wastewater treatment plant can expect reductions in greenhouse gas emission in the range of 3,000 to 5,000 tonnes a year, comparable to reducing truck travel by 3.2 to 4.8 million kilometres annually.

ARP, known as a physical/chemical process, sets a new standard for energy-efficient, cost-effective and very reliable treatment of ammonia stemming from wastewater treatment plants. The ammonia removed from wastewater streams is converted it into ammonium sulphate, a commercial fertilizer. The compact size of the ARP process allows it to be retrofitted into existing wastewater treatment plants.

Besides reducing greenhouse gas emissions, ARP is claimed to be almost five times cheaper to build than other comparable biological systems, require less than one-third the space and results in major reductions in energy requirements, chemical use and sludge production. Contact: Dennis C. Cossey, Chairman & CEO, ThermoEnergy Corporation, 124 W Capitol Avenue, Ste 880, Little Rock, AR 72201-3719, United States of America. Tel: +1 (501) 3766477; E-mail:


Compact, innovative biological wastewater treatment

An innovative biological wastewater technology from AnoxKaldnes, Sweden, helps municipal and industrial wastewater treatment plants meet stringent discharge standards. The MBBR technology is an attached-growth biological wastewater treatment, which is less expensive than conventional biological treatments. It uses engineered plastic media to promote fixed biomass. This makes for an easy-to-operate and efficient wastewater treatment, which does not require recirculation of the mixed liquor suspended solids (MLSS). The MBBR technology can be used for the treatment of both carbonaceous and nitrogenous pollution, in both municipal environments or in industrial settings.

The main types of the MBBR technology are: (1) BAS, an optimally designed combination of an MBBR stage and a later activated sludge stage; (2) HYBASTM/IFAS, an activated sludge process and the MBBR biofilm process combined into one; and (3) LagoonGuardTM, for a well-designed supplementary MBBR to polish off the ammonium load and may even provide additional COD removal. Contact: Ms. Lisa Schilling, AnoxKAldnes, Veolia Water Solutions & Technologies, 23563 W. Main Street, Route 126, Plainfield, Illinois 60544, United States of America. Tel: +1 (815) 609 2000; Fax: +1 (815) 609 0490.


Submerged anaerobic membrane bioreactor

A team comprising scientists from Imperial College London, Anglian Water, and Black & Veatch in the United Kingdom is all set to demonstrate on large scale a revolutionary wastewater treatment process to alleviate water scarcity while being self-sustainable.

Professor David Stuckey at Imperial College London pioneered laboratory studies into wastewater treatment using submerged anaerobic membrane bioreactors (SAMBR). An independent verification of the process at Cranfield University was sponsored by Black & Veatch. The study confirmed that the low footprint SAMBR can indeed achieve a high quality effluent suitable for wastewater reuse, with a positive net energy yield and very low sludge production.

Anaerobic membrane bioreactors have previously only been used for industrial wastewater treatment with concentrated and warm effluents. The prototype being developed is a full-scale 50 m3 of water per day unit. The plant will recycle wastewater, will produce enough energy to power itself and, with just a few hours of detention time, will be much smaller than traditional plants. The plant will be hosted by Anglian Water at its Water Innovation Centre in Cambridge. In parallel with the field work, ongoing research will further develop the SAMBR system. The project partners anticipate the SAMBR will become a cornerstone process in the wastewater industry, attracting a considerable market within the environment industry globally.


FGD wastewater treatment system for power plants

Shaw Group Inc., the United States, has selected Siemens Water Technologies to provide a system to treat wastewater from flue gas desulphurization (FGD) scrubbers being constructed at three different power plants. The system will remove suspended solids, heavy metals and organics from the scrubber waste stream so that the water can be safely discharged.

Siemens will design and supply the new physical/chemical and biological wastewater treatment system, as well as provide start-up, training and commissioning services. Each wastewater system will include storage and reaction tanks, chemical feed systems, a clarifier, biological reactors, gravity sand filters and filter presses. The system flow rates are 45 m3/h for one plant and 25 m3/h each for the other two.

An equalization tank receives the waste stream and equalizes the flow to eliminate spikes in flow rates and concentration. Next, two reaction tanks in series continue the treatment to de-saturate the wastewater, reduce heavy metals, and prepare the wastewater for clarification. In the clarifier, suspended solids are coagulated and settled. Solids are dewatered in the filter presses. The treated water is sent to sequencing batch biological reactors for nitrogen reduction. Gravity sand filters carry out final treatment before discharge. Contact: Mr. William Scully, Siemens Water Technologies, 181 Thorn Hill Road, Warrendale, Pennsylvania 15086, United States of America. Tel: +1 (800) 525 0658; Fax: +1 (724) 772 1300.



Detoxifying wastewater through bioremediation

Laccases are copper-containing oxidases produced by white-rot fungi (WRF) for extracelllular lignin degradation. Laccases are commercialized as industrial catalysts with applications in textile dyeing/finishing, wine cork making, and many other industrial, environmental, diagnostic and synthetic uses. Under European Union’s SOPHIED project, Wetlands Engineering of Belgium has been developing immobilized laccase as the workhorse in a bioremediation process for wastewater from the dyeing industry. Laccases from several WRF were shown to be able to effectively decolourize and detoxify industrial colorants in lab-scale quantities in Petri dishes or shaken flask cultures.

Wetlands Engineering uses a process developed by other partners in the SOPHIED project to produce up to 5 MU of laccase activity per batch of WRF bioreactor culture. Immobilization of the enzymes is necessary to allow for a continuous or fed-batch type of treatment system. The proprietary method of immobilization used results in very high enzyme activities. A major advantage of this method of immobilization is that low purity laccases will suffice for a high yield of immobilization, significantly reducing the cost of down-stream processing.

The bioremediation method is very effective in decolourizing industrial wastewater from the dyeing industry and has a significant effect on the chemical oxygen demand value of the wastewater. Most of the colorants are also detoxified although bioactivation is also observed in rare cases.


Bioremediation of TCE and TCA

Dr. R.J. Cadorette and colleagues at Shaw Environmental Inc., the United States, have completed a successful programme of sodium permanganate (NaMnO4) treatment to eliminate trichloroethene (TCE) contamination at a manufacturing site. The treatment regime involved the injection of over 670,000 litres of a 20 per cent NaMnO4 solution into the shallow overburden, deep overburden and bedrock aquifers at the site over a period of four years. The NaMnO4 applications resulted in significant reductions in TCE concentrations across the site.

Following the NaMnO4 treatment, enhanced bioaugmentation with injections of sodium lactate, the SDC-9 culture and trichloroethane (TCA)-reducing bacteria was carried out. The bioremediation programme targeted both TCE contamination next to a stream (where NaMnO4 injection was not feasible) and residual TCA impacts in the deep overburden. Technical aspects of implementing bioaugmentation in an area previously treated with NaMnO4 include the quenching of residual NaMnO4 concentrations with lactate, the potential for solubilizing manganese under reducing conditions, and the ability to achieve complete dechlorination of TCE and TCA.


Enhancement of in situ bioremediation of explosives

A joint research in the United States by scientists from the Pacific Northwest National Laboratory, United States Army Engineering Research & Development Centre and School of Natural Resources attempted to quantify processes and determine the effectiveness of abiotic/biotic mineralization of energetics (RDX, HMX, TNT) in aquifer sediments by combined bio-stimulation (carbon, trace nutrient additions) and chemical reduction of sediment to create a reducing environment.

The researchers found that optimal sediment treatment for RDX and HMX (which have chemical similarities and similar degradation pathways) is mainly chemical reduction of sediment, which increased the RDX/HMX mineralization rate 100-150 times relative to untreated sediment. A secondary treatment using carbon or trace nutrients increased the RDX/HMX mineralization rate 3-4 times. In contrast, the optimal aquifer sediment treatment for TNT involves mainly bio-stimulation (glucose addition), which stimulates a TNT/glucose cometabolic degradation pathway (6.8 times more rapid than untreated sediment), followed by a chemical reduction (13 times rate increase). TNT is transformed to triaminotoluene, which irreversibly sorbs in reduced systems but is rapidly degraded in oxic systems. Although the TNT degradation pathway is biologically dominated, the iron-reducing conditions created by abiotic reduction of sediment promote faster abiotic degradation of amino-intermediates than biodegradation of these intermediates.


Clean water with bioremediation and nanofiltration

Scientists at the University of Nottingham, the United Kingdom, are using bacteria alongside the very latest membrane filtration methods to improve and refine water cleaning technology. The contaminated water is first treated using bioremediation, and then filtered through porous membranes, which function like a sieve. These membranes have microscopic holes – from 10 µm to 1 nm in diameter. These technologies can become processes that optimize the use of water. The study is led by Professor Nidal Hilal at the Centre for Clean Water Technologies – a world-leading research unit developing advanced technologies in water treatment.

Current membrane technology used in water treatment processes can decrease in efficiency over time, as the membranes become fouled with contaminants. The membranes can be cleaned, without removing them, by using bioremediation. Besides being highly effective in the water treatment process, transforming industrial liquid waste contaminated with metals and oils into clean water, ultrafiltration and nanofiltration membranes have a useful side-effect. As the waste products have a very high calorific value, they can be used as fuel.


Bioremediation for radionuclides in radioactive water

Spain’s Universidad Politecnica de Madrid and Iberdrola Generacion SA have been jointly assigned a United States patent on a method for concentrating and eliminating radionuclides from water from in nuclear pools. The method is based on the capacity of micro-organisms to retain radionuclides by forming biofilms on the colonized surfaces when they are growing. The bioremediation is performed before the water passes through demineralizing filters. As a result, there is less radioactive waste to be managed, thereby increasing the profitability of the method.

The radioactive water goes through a bioreactor that contains a metallic material, such as stainless steel or titanium wound into a ball, or any other material that is non-corrosive or non-degradable in this environment and can be colonized by the micro-organisms that exist in this type of water. As it goes through the bioreactor, the water contacts with the material, forming a biofilm that retains the radionuclides. The micro-organisms are capable of retaining the radioisotopes by bioadsorption, bioabsorption, bioaccumulation, biosolubility and/or bioprecipitation.

The water then goes out from the opposite end of the continuous-flow entrance and, before going back into the pool, it goes through a set of demineralizing filters. The material of the bioreactor is replaced as necessary. The biofilm that retains the radionuclides is economically eliminated by any conventional decontamination procedure. The radionuclides can be concentrated in a small volume of eluent for recuperation, disposal or containment. At this point, the material from the bioreactor can then be managed like non-radioactive material.


Remediation of crude oil spills by microbes

Nigerian researchers have developed a mixed culture of compatible hydrocarbonoclastic and diazotrophic bacteria for bioremediation of crude oil-contaminated soils. The researchers have also explored a combination of treatments, consisting of the application of fertilizers and oxygen exposure in situ during a period of six weeks. They have also examined two Pseudomonas species – P. fluorescence and P. aeruginosa for their degradation potential of phenol in refinery effluent.

The researchers at the Department of Biochemistry, University of Nigeria in Enugu State found that beyond their role in biological nitrogen fixation, diazotrophs may be used to aid the bioremediation of crude oil-contaminated land. The scientists also investigated the ability of the indigenous white-rot fungi Lentinus subnudus to mineralize soil contaminated with crude oil of different concentrations.

The hydrocarbonoclastic bacterium, Pseudomonas species, and the diazotroph, Azotobacter vinelandii, were both isolated from a previously crude oil-contaminated soil. They were then modelled as a mutualistic consortium in situ. Stabilization of the consortium, and hence the optimized bioremediation process, occurred when the bacterial growth attained a pseudo-steady state. This was considered to be the result of a symbiotic association between A. vinelandii and the Pseudomonas in which A. vinelandii produced the required concentration of fixed nitrogen compounds for the growth of the Pseudomonas species.

Enhancement in biodegradation was mathematically evaluated as the difference in the specific growth rates between Pseudomonas alone and the Pseudomonas-A. vinelandii consortium. The proportion of petroleum hydrocarbons degraded by the consortium from the contaminated soil ranged from 66.83 to 69.6 per cent as compared with the 23.2-44.45 per cent of a pure culture of Pseudomonas.



NOx treatment with electrochemical reactors

The Institute of Solid State Physics, Russia, has developed nanostructured electrochemical reactors for achieving dramatic improvement in the selective separation and purification of nitrogen oxides (NOx) in exhaust gases. The novel electrochemical cells for NOx treatment function through nanoscale control of penetrating pores from the catalytic electrode surface to the bottom of the catalytic electrode layer, and by distribution at the interfaces of ionic and electronically conducting grains through the electro-catalytic electrode of the cells.

Remarkable improvements in the current efficiency and suppression of the working voltage of the cells enabled their application as a novel reactor for NOx decomposition in gases from petrol and diesel engine vehicles, gas engines and other industrial equipment with the advantage of less energy consumption. The cells are able to work as a deNOx reactor for the selective separation of NOx molecules even with oxygen content in excess by 10 per cent or more. This is the first time such nanoscale reaction has been shown to realize sufficiently applicable yielding rates.


Ultra low NOx biogas-to-power conversion technology

Soaring energy prices and rising concerns about energy security and global warming, along with the growing availability of high-value waste streams and opportunity fuels, have renewed interest in systems that convert waste into energy. To enable owners of these high-value waste streams to utilize these new growth opportunities, TIAX LLC, the United States, has developed internal combustion engine-based biogas conversion technologies that use the Hydrogen Assisted Lean Operation (HALO) to achieve ultra-low emissions (45 g/MWh NOx) and high efficiency (34-38 per cent for LHV) at low cost. BioHALO (HALO applied to biogas engines) is partcularly attractive in cases where permits for new waste-to-energy installations are difficult to secure and existing installations are being closed down for not meeting strict NOx emissions requirements. BioHALO generates emission reduction credits that can offset emissions at other sites or be sold at lucrative prices. The advantages of BioHALO technology have been demonstrated on a 75 kW gas-fired engine co-generation unit test facility at TIAX, Cambridge, in partnership with the California Energy Commission.


Low-energy bubble scrubber

The ENVI-Clean low-energy bubble scrubber, from EnviroResolutions, Canada, removes targeted gaseous properties and particulate matter from air streams. Unlike other wet scrubbers, which use sprays and water droplets, EnviroResolutions’ technology mixes the hot exhaust gas and liquid in a highly turbulent mixing zone to produce a fine bubble distribution between the hot gas and the scrubbing liquid. This creates a high surface area of contact between the gas and liquid, thereby enhancing osmotic transfer between the two phases. This transfers the particulate and targeted gaseous pollutants, from the exhaust to the liquid at a significant cost saving.

The scrubber targets the reduction of oxides of sulphur (SOx), oxides of nitrogen (NOx), unburned hydrocarbons, soot and ash (particluates). The pilot plant has shown impressive results: 96 per cent removal of SOx, 20 per cent of NOx, and 89-95 per cent of particulate matter. No degradation in fuel efficiency was observed. Contact: EnviroResolutions Inc., 1560 Richmond Street, North Vancouver, British Columbia V7J 1B2, Canada. Tel: +1 (604) 987 6543; Fax: +1 (778) 340 5567; E-mail:


Volatile organic compound system

Knutsen OAS Shipping AS, Norway, has developed a method to reduce emission of volatile organic compounds (VOCs) from carrier ships while loading and transit. Besides being an environmental hazard, the emission of VOCs into the atmosphere, is also a considerable loss of value.

The reasons for VOCs formation in crude oil have been investigated and it was discovered that in most cases the crude oil is to a low pressure during loading into ships. This low pressure causes the light ends of the crude to vaporize. The VOCs generated will not be reabsorbed but displaced to the atmosphere during loading and transit. The new technology called KVOC® prevents this vapour release. KVOC ensures that low pressure is prevented by redesign of the loading arrangement. Tests and verifications have documented 60-70 per cent reduction of VOCs. KVOC has a similar effect on reduction of hydrogen sulphide too.

Knutsen has installed several KVOC systems on crude oil and product carriers. The technology is available for anyone interested in reducing the environmental impact from tankers. Contact: Knutsen OAS Shipping AS, Post Box 2017, N-5504 Haugesund Norway. Tel: +47 52704000; Fax: +47 52704040; E-mail:; Website:


Knocking the NOx out of coal

Coal-burning power plants produce a lot of nitrogen oxides (NOx), which are air pollutants. One of the best ways to reduce NOx is to prevent it from forming in the first place. Scientists have found ways to burn coal (and other fuels) in burners where there is more fuel than air in the hot combustion chambers. Under these conditions, most of the oxygen in the air combines with the fuel, rather than with the nitrogen. The burning mixture is then sent into a second combustion chamber where a similar process is repeated until all the fuel is burned.

This concept is called “staged combustion” because coal is burned in stages. A new family of coal burners called “low-NOx burners” has been developed using this way of burning coal. These burners can reduce the amount of NOx released into the air by more than half. There is also a family of new technologies that work like “scrubbers” by cleaning NOx from the flue gases of coal burners. Some of these devices use chemical catalysts that break apart the NOx into non-polluting gases.

Although these devices are more expensive than low-NOx burners, they are able to remove up to 90 per cent of NOx pollutants. Contact: The United States Department of Energy, 1000 Independence Avenue, SW, Washington, DC 20585, United States of America. Tel: +1 (202) 586 5000; Fax: +1 (202) 586 4403; E-mail:


New electrochemical reactor for efficient decomposing of NOx

The Functional Assembly Technology Group at Advanced Manufacturing Research Institute of Japan’s National Institute of Advanced Industrial Science and Technology (AIST) has developed an electrochemical reactor. The reactor can efficiently purify nitrogen oxides (NOx) in diesel exhaust gas by breaking them down into nitrogen and oxygen at low temperatures without using a catalyst.

The nanostructure electrode formed in the reactor makes it possible to break down NOx in diesel exhaust gas containing a high concentration (approx. 20 per cent) of oxygen at temperatures below 250ºC. Moreover, the new reactor can reduce the energy needed to purify exhaust gas, thereby contributing to the improvement of fuel efficiency. The reactor enables the system to conserve air environment while reducing carbon dioxide. Thus, it is likely that the reactor can replace the existing exhaust gas purification systems in diesel cars when controls on emissions are tightened.

In 2001, AIST succeeded in developing a solid electrolyte electrochemical reactor, which made it possible to break down and remove NOx included in a gas containing oxygen in a highly selective manner. However, this reactor was impractical for use as it was difficult to lower its operating temperature. Thus, AIST designed a new electrode structure based on selective NOx breakdown mechanism and developed a highly efficient NOx breakdown/purification reactor that is operable at low temperatures.

The nanostructured working electrode makes use of an electrolyte with high oxygen ion conductivity. As a result, the area of three-phase interface – composed of electrode, electrolyte and gas – that acts as a reaction point is increased and the activity of the interface is enhanced. At the same time, an atmosphere formed in the electrode section, where the NOx breakdown predominantly occurs, greatly reduces the operating temperature.

The electrochemical reactor using this nanostructured electrode exhibited a high reactivity to NOx and was capable of purifying approximately 90 per cent of 1,000 ppm NO gas in an atmosphere containing 20 per cent oxygen (an oxygen concentration higher than that in the actual diesel exhaust gas composition) and 80 per cent nitrogen at a temperature of only 250ºC. AIST aims to further reduce the operating temperature and enhance the integration of reactive area. It is also planning to evaluate the durability and the influences of co-existing gases to consider the feasibility of the latest reactor.


NOx reduction systems for industrial power plants

Babcock Power Environmental Inc., the United States, has introduced an innovative and high-efficiency nitrogen oxides (NOx) reduction technology designed to reduce the NOx emissions from boilers at large industrial power installations. The regenerative selective catalytic reduction (RSCRTM) system provides a relatively inexpensive alternative to achieve high NOx removals from boilers firing certain fuels.

The RSCR system is targeted at tail-end/low-temperature applications where the flue gas is relatively cool and clean of particulates. It combines the company’s expertise in selective catalytic reduction (SCR) systems with proven high thermal efficiency and heat-recovery technology, to offer a more compact, ef-ficient and modular product capable of removing more than 70 per cent of NOx. Installation time at the site is also minimized, helping to further reduce total project installation time and cost. Contact: Babcock Power Environmental Inc., 5 Neponset St., Worcester, MA 01606, United States of America. Tel: +1 (508) 852 7100; Fax: +1 (508) 852 7548; E-mail: info


Innovative low-NOx combustor

Researchers at Japan’s IHI Corporation have developed a gas-turbine combustor for environment-friendly and economical aircraft engines adaptable to 50-seat class jet airplanes. The combustor has a simple structure and low nitrogen oxides (NOx) emission characteristics. The target level of NOx reduction was 50 per cent or less, which corresponds to requirements of the International Civil Aviation Organization (ICAO) CAEP 4. A special simple structure swirler, named a cross-jet swirler, was developed. Test results revealed a significant reduction of NOx emissions, to more than 56 per cent of the present ICAO CAEP 4 requirements for the landing and take-off cycle. Furthermore, carbonmonoxide emissions were reduced by 19 per cent, and total hydrocarbons by 59 per cent compared with the reference values of the ICAO requirements.


Removal of gaseous pollutants from upward flowing gas

E.E.R. Environmental Energy Resources, Israel, and three inventors have been jointly assigned a WIPO patent on a method and apparatus for the removal of gaseous pollutants from an upwardly flowing gas stream. The technology comprises injecting an adsorbent into a turbulent region of the gas stream in a counter-current direction. The apparatus comprises a vertical adsorption column with a convergent inlet cone, throat and a divergent outlet cone, through which a gas stream flows at an angle of 0º-45º relative to the vertical plane (upwards).

A vortex generator is mounted in the throat coaxially with the gas flow. It preferably comprises vane elements, inclined at 5º-15º angle, for producing vortices in the gas stream, downstream to the vortex generator. An unobstructed annular area exists around the vortex generator, so that a region of turbulence of the gas stream is created around the central longitudinal axis of the apparatus and a laminar flow of gas is generated along its walls.

The reactor is of a type in which the reaction – caused or facilitated by adsorption, a chemical or physical phenomenon, or a combination of the two – occurs in a place filled with a material that is generally in gas phase, but may contain solid particles. The adsorbent material, which is introduced to the reactor, is adapted to remove gaseous pollutants from a gas stream. The retention time of the adsorbent in the turbulent region is about 2-20 times more than the retention time of the adsorbent in the laminar peripheral stream. Suitable flow conditions for effecting the method of the inventions are such that the gas stream has a temperature ranging from 0º to 300ºC and a density ranging from 0.6 to1.5 kg/m3, and flows at a velocity ranging between 0.6 and 25 m/s within the throat.




Introduction to Plastics Recycling (2nd Edition)

As in the successful first edition, this book provides straightforward information on plastic materials and technology, including the options for recycling plastics, with special focus on mechanical recycling. It touches on all the major problems associated with recovering and recycling plastics at a level intended to be accessible to any reader with an interest in this field, whatever their background. It also looks at some of the broader issues surrounding successful waste management of plastics. This new edition reflects the great strides that have been made to increase recycling rates worldwide in recent years.

Contact: Smithers Rapra Technology Ltd., Shawbury, Shrewsbury, Shropshire, SY4 4NR, United Kingdom. Tel: +44 (1939) 252413; Web:

E-Waste, Vol. 1: Inventory Assessment Manual

This book is the first volume of E-waste manual to build the capacity of practitioners and policy makers for preparing WEEE/E-waste inventory. The objective of the manual is to identify E-waste as an environmental issue and to quantify its extent. This manual summarises the available legislations on WEEE/E-waste in different countries and provides a methodology to design and use E-waste inventory assessment studies/projects. This manual also provides case studies from developing countries.


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