VATIS Update Waste Management . Mar-Apr 2005
IN THE NEWS
New regulations for scrap entering China
| According to the Bureau of International Recycling (BIR), a recent Commission Regulation that affects European scrap exports to China came into effect from 11 February 2005. The new regulation concerns exports of certain types of Annex II Green List wastes under normal commercial rules, adding cotton and yarn wastes to the previous goods allowed. Meanwhile, all other Annex II Green List waste materials that are not wanted under normal commercial rules like GC010 (metals and alloys) and GC020 (printed circuit boards) become automatically Red Controlled as do unlisted non-hazardous wastes.
Since 1997, the European Union (EU) has been implementing the UNEP Basel Convention ban, which banned the export of all hazardous wastes from the EU to China. In a note to its members, BIR stated that owing to the EU and OECD listing variation from the Basel Convention, a consequence is that China may not ban the import of certain end-of-life products, those being Red Controlled instead.
Wastes raise public health concerns in Viet Nam
| According to the latest report by Viet Nam Environment Monitor, the 15 million tonnes of waste generated each year in the country poses a serious threat to public health and the environment. By 2010, municipal waste is expected to increase by 60 per cent, industrial waste by 50 per cent and hazardous waste by 300 per cent. The Monitor states that challenges facing Viet Nam include improving the financial and social sustainability of solid waste management investments as well as ensuring protection of vulnerable groups, like waste pickers, poor women and children.
Viet Nam Environment Monitor is sponsored by the Viet Nam Ministry of Natural Resources and Environment, World Bank and the Canadian International Development Agency.
Contact: Mr. Hoang Thanh Ha, Viet Nam. E-mail: email@example.com ; Or Ms. Melissa Fossberg, World Bank, United States of America.
Basel convention ruling on dumping obsolete ships
| According to a recent decision under the Basel Convention, ships can be considered as toxic wastes under international law. As such, all the 163 signatories are obliged to control the export of ships under the terms of the convention. In 1995, the Basel Convention imposed a ban on toxic waste exports, including products meant for recycling, from developed to developing countries. However, toxic wastes like asbestos, PCBs, hazardous paints and fuel residues present as components in old ships have continued to be off-loaded on to nations like Bangladesh, India, Turkey and China, among others. By explicitly declaring redundant ships as waste, this ship-sized loop hole has been plugged. The United States, Japan and representatives of the shipping industry struggled in vain to block the decision, which also recognized the importance of improving shipbreaking facilities in developing countries.
As per the new ruling, signatories have to apply the Basel Convention to ships marked for breaking. These countries must prohibit exports without the consent of recipient nations, and must assure that shipbreaking is performed in an environmentally sound manner and transboundary movement of hazardous wastes is minimized. The latter obligation can be expected to increase demands for decontamination of ships prior to export, which had been urged during a conference by the shipbreaking countries of India, Bangladesh and Turkey. The United States, which is not a Basel signatory, denounced the decision arguing that it does not believe end-of-life ships are waste. It is currently seeking a home for its fleet of redundant ghost ships.
Indonesia pushes waste management
| Indonesia plans to proceed with its funding programme for small and medium businesses that produce compost from garbage. Indonesia produces roughly 70 m3, or 20,000 t, of domestic waste each day. The issue of waste management came up at a seminar, organized by the World Bank and the Office of the State Minister of Environment, to address one of the key issues in urban environmental management in Indonesia.
Since its inception in 2001, this programme, set up with the support of the World Bank, has benefited only 21 waste management companies owing to lack of publicity. An official of the ministrys information division, Ms. Laksmi Widayanti, agreed that promotion of the project had been weak and that many applicants could not submit appropriate proposals in line with the standards set by the bank and the ministry. The Bank has provided a US$10 million fund with the aim of reducing the countrys urban waste by 60,000 t within three years by disbursing subsidies to the selected compost producers who meet the criteria for assistance. The first phase of the programme, funds for which was disbursed in December 2003, was carried out through the Western Java Environmental Project (WJEP) and covered the provinces of West Java, Jakarta and Banten.
Sino-Canadian dioxin research lab set up
| A laboratory exclusively devoted to dioxin research has been set up in China. This project was sponsored by Chinas Zhejiang Province, along with Alberta Province in Canada. The Canadian counterpart provided financial and technological support as well as personnel training. Four scientists from the Zhejiang Provincial Centre for Disease Control and Prevention, which oversees the laboratory, have been trained. The US$922,000 facility provides dioxin analysis/testing services involving chemical products, environmental samples, foodstuffs and fodder. It has also commenced analysis of dioxin residue in freshwater fish.
Solid waste collection improves in Viet Nam
| Nearly 71 per cent of solid wastes generated in Viet Nams urban areas and industrial zones are now being gathered and dumped at designated sites, compared with 40 per cent five years back. During a meeting of the Ministry of Construction it has been reported that the collection rate for recyclable rubbish, including plastic and glass, stood at 25 per cent. This meeting reviewed waste collection for the 2000-2004 period and also discussed implementation of the national strategy on management of solid waste in urban and industrial zones through to 2020. Different measures were put forward and a plan of action formulated to implement the strategy during 2005-10.
Progress has also been achieved in waste treatment, with the building of new treatment facilities at Viet Tri, Vinh, Hue, and Ba Ria-Vung Tau and the application of Seraphin technology to treat and recycle solid waste. However, to date only 13 of the nations 64 provinces and cities have waste dumping grounds that comply with hygienic standards. Most of the waste is not sorted before being dumped. Hospital waste is another major concern, as most of it is not properly treated.
China amends law on solid wastes
| In China, the 13th session of the Standing Committee of the 10th National Peoples Congress (NPC) approved an amendment to the law on solid waste pollution prevention for resolving the serious challenges raised by mounting solid waste piles. This latest measure is intended to safeguard the health of the public, maintain bio-environmental security and promote sustainable economic and social development. The law, which comprises 6 articles and 91 clauses, will come into effect from 1 April 2005. Under this legislation, governments at the county level and above will have to include solid waste control in their projects for economic and social development.
Loans for green recycling process
| In India, the West Bengal Pollution Control Board intends to provide a packaged deal on a new recycling technology to plastic recyclers in West Bengal. This measure will be supported by the state government and the Centre for Quality Management System (CQMS), which has developed a recycling technology to lower emissions by 90 per cent while raising productivity. At present, plastic recycling units use archaic technology that emits huge volumes of pollutants. According to CQMS, retrofitting certain existing equipment with new ones would reduce emissions and also bring down the investment cost to about US$1,050.
Malaysian law to compel recycling
| The Malaysian government is slated to introduce a new law that makes citizens responsible for recycling wastes. Housing and local government Minister Datuk Seri Ong Ka Ting expressed that once the Solid Waste Management Bill is tabled, numerous parties, including waste management consortiums and the public, will be compelled by law to recycle. This programme will add fire stations to the list of recycling points, which already includes petrol stations, schools, etc. Under the programme, the ministry will provide recycling bins and plastic bags for the fire station personnel and their families to collect items for recycling. Garbage is a serious problem in the country, with every person generating 1.5-1.8 kg/d of waste in urban areas.
Korea to save and recycle resources
| In the Republic of Korea, an amendment to the Act on Promotion of Saving and Recycling of Resources will be enforced from 2006. Drafted and proposed by the Ministry of Environment in an effort to expand and improve the extended producers responsibility system (EPR), among others, the amended act has been approved by the Cabinet Council. From January 2003, EPR system is being applied to 15 items air-conditioners, personal computers, televisions, laundry machines, audio cassettes, refrigerators, cell phones, tyres, lubricating oil, fluorescent light bulbs, batteries and plastic packaging materials like paper packs, metal cans, glass bottles and even synthetic resins. The amendment will add three electronic products printers, copy machines and fax machines to the list of mandatory recycling items under EPR.
Presently, each producer under EPR system receives mandatory recycling obligations per EPR item, set by taking into account the quantity of product released two years back. From this year onwards, the amendment will enable greater efficiency by considering business fluctuations in each year to estimate the recycling obligation.
China enforces rules for scrap imports
From 1 January 2005, overseas firms either from foreign nations or Hong Kong, Macao and Taiwan regions are banned from supplying scrap to China if they have not registered with the State Administration for Quality Supervision and Inspection and Quarantine (SAQSIQ). Scrap from unregistered exporters will not be allowed to enter the country. Overseas scrap suppliers were required to apply for import eligibility, along with quality control and environmental management guarantees by the end of December 2004. SAQSIQ has approved over 2,000 registration applications from countries such as Argentina, Republic of Korea and the United States, as well as European countries. Port inspectors examine scrap consignments on arrival using advanced inspection equipment to ensure compliance with the national parameters set for environmental protection and safety.
Vehicle recycling law
| Japan stepped up efforts to recycle cars and prevent them from being dumped illegally by enforcing a new law that requires manufacturers to charge drivers for recycling their vehicles. Under the new law, which entered into force on 1 January 2005, automakers and car importers are required to collect and recycle CFCs, air bags and residues from shredded vehicles. The mandatory vehicle recycling legislation is intended to raise automobile recycling to 95 per cent in 2015 from the present level of around 80 per cent. From 2005, the sticker price of a new car will include the recycling cost.
India lifts ban on scrap metal imports
| The Director General for Foreign Trade (DGFT), India, announced that it will permit imports of scrap metals at various container ports, including Ludhiana port. A notice by DGFT states that imports of metallic waste and scrap in unshredded, compressed and loose form would now be admitted. Scrap imports were banned after explosives were found in some scrap consignments. Other ports where such scrap and waste imports have been permitted are Chennai, Cochin, Ennore, JNPT, Kandla, Moriugad, Kolkata, New Mangalore, Vishakhapatanam, ICD Tughlakabad, Paradip, Tutirocin, Pipavin, Mumbai, Mundra, and ICD Dadri, Greater Noida.
Recycling hospital wastes in Pakistan
| Hospital wastes in Pakistan are not safely disposed of. Such wastes are either dumped at community waste sites or sold directly to junk dealers. According to an estimate, out of the 8,000 t/d of garbage generated in Karachi, 0.5 per cent comes from the medical fraternity. A study by the Environment Protection Agency reveals that 20 per cent of hospital wastes produced every day in the city is infectious. On an average, scavengers and sweepers who sort and handle this hazardous waste at community dumping sites report 3-5 needle stick injuries in a day. Junk dealers also frequently fall prey to this menace. In Karachi, the city government provides a disposal service that collects and incinerates waste from hospitals for a price, Despite this, most hospitals prefer to dump their waste in the open.
Malaysian move to keep out toxic wastes
| A new standard quarantine operating procedure implemented in Malaysia has made it harder for toxic wastes to enter the country. The new measure involves a number of enforcement agencies, including Interpol, and pools together human resources and expertise from the Department of Environment (DOE), Customs and Excise, police, etc.
| In Germany, Deutsche Gesellschaft fr Kunststoff-Recycling mbH (DKR) is offering a PET recycling concept, which is essentially based on resorting in bottle processing plants. Using modern optoelectronic technology, bottles are separated by plastic type and colour. Near-infrared units first separate the material into the target fractions polyethylene (PE), polypropylene (PP) and PET. Next, colour detection systems sort PET more carefully, separating the bottles into clear PET and coloured PET, which could further be sorted into light blue and green PET.
DKR also promotes development of polyols from used PET sales packaging. Polyols are in great demand as basic starting materials for the production of polyurethane (PUR), which is used in the building sector as PUR foam for thermal insulation.
Contact: Deutsche Gesellschaft fr Kunststoff-Recycling mbH, Frankfurter Strasse 720-726, Cologne 51145, Germany. Tel: +49 (2203) 9317 745; Fax: +49 (2203) 9317 774
Direct dry distillation of waste tyres
| Fujikasui Engineering Co. Limited, Japan, utilizes tyres in its distillation furnaces without any shredding or sorting. The waste tyres are baked by furnishing a modest amount of combustion air, which is far less than that required for total combustion. Dry distilled gas thus obtained is cooled using a cooler, and part of the gas liquefied and recovered in the form of oil. The rest of the gas, which cannot be condensed in the gas cooler, is completely incinerated in the incinerator or boiler. Wire and carbon remain as residue in the furnace.
Contact: Fujikasui Engineering Co. Ltd., 1-4-3, Higashi-gotanda, Shinagawa-ku, Tokyo 141 0022, Japan. Tel: +81 (3) 3445 1711; Fax: +81 (3) 3445 6400
Chemical recycling of PVC wastes
| Nikkiso Co. Ltd., Japan, is offering a new technology, which facilitates chemical recycling of soft polyvinyl chloride (PVC). The company has established a pre-treatment method that separates the plasticizer from pulverized feed material in a subcritical aqueous environment. Also, technology has been developed to extract the plasticizer without damaging the PVCs structure. This process enables conversion (material recycling) of PVC. Furthermore, a two-stage procedure segregates chlorine after the plasticizer has been removed. Efforts are on to achieve material conversion in supercritical conditions for the production of value-added material.
Contact: Nikkiso Co. Ltd., 3-43-2, Ebisu, Shibuya-ku, Tokyo 150 8677, Japan. Tel/Fax: +81 (3) 3443 3711/3473 4963.
Processing mixed plastic wastes
| Pla.to GmbH, Germany, is offering two cost-effective technologies to process non-homogeneous mixed plastic wastes into pourable agglomerates that are ideal for chemical recycling processes. These are:
Contact: Dr. Ing. Michael Heyde, Executive Manager, Pla.to GmbH, Frankfurter Str. 720-726, D 51145 Koln, Germany. Tel: +49 (2203) 937 600; Fax: +49 (2203) 937 690
Natural alternative to PET separates easily
| Research undertaken by National Recovery Technologies (NRT), the United States, has indicated that NatureWorks PLA segregates from PET bottles as part of a fraction that reclaimers presently remove using NRT infrared systems. NatureWorks PLA from Cargill Dow is a 100 per cent natural alternative to petroleum-based plastics. The NRT data are consistent with other studies using infrared technology to sort NatureWorks PLA from PET streams.
Also, MSS companys high-capacity Aladdin system has demonstrated that NatureWorks PLA has a unique signature in the near-infrared range, which facilitates the polymer to be distinguished from PET and other plastics. In addition, Germany-based TiTech VisionSort has evaluated the segregation of NatureWorks PLA from PET and reports that the PET alternative also has a very unique infrared scan. The companys Auto Sort equipment was able to separate NatureWorks PLA fragments and bottles from a stream that included PP, PET, PETG, PC, PS, EPS and ABS at standard efficiency rates.
New equipment for recycling plastics
| Engineering Recycling Maschinen und Anlagen Ges.m.b.H. (Erema), Austria, offers a fourth generation system equipped with the very latest technologies. The 1,000-1,200 kg/h RGA 140 TVE-DD model features several large and small innovative advances, representing premium recycling technology. The patented T-DD technology symbolizes the latest in plant technology by using two discs in the Erema compactor/cutter. This breakthrough results in separating the shredding, mixing, drying and pre-homogenizing steps from the extruder feeding step. As such, uniform extruder operation is achieved despite feed sizes being considerably bigger than before. Also, materials with considerably higher moisture contents can be processed easily, compared with cutter compactor single disc executions. However, the key attribute of this technology is the capacity, which is up to 15 per cent higher on average (with no change in plant size), with simultaneous reduction in specific energy consumption by up to about 20 per cent.
The T-DD system can be retrofitted (within limits) to existing facilities. Customer feedbacks indicate that the accumulated production throughput of classic Erema recycling units incorporating the T-DD upgrade is increased by up to 15 per cent. In some specific applications such as BOPET film waste processing, the new system delivers extraordinary advantages like eliminating extruder degassing and vacuum pumps, 20-30 per cent energy savings when compared with the older degassing extruder PET processing system, etc.
Contact: Engineering Recycling Maschinen und Anlagen Ges.m.b.H, Freindorf - Unterfeldstrae 3, P.O.B 38, A-4052, Ansfelden/Linz, Austria. Tel/Fax: +43 (732) 3190-0/3190-23
Granulator for PET bottles
| Nuga AG, Switzerland, offers a new series of CentriCut 44 granulators that are specially designed to grind PET bottles. Bottles released from bales as individual briquettes or in perforated, compressed form are fed into the granulator using a conveyor belt. A horizontally arranged screw conveyor forces the material axially on to the rotor from inside. The rotor is open, with three or five rows of rotor blades around the perimeter. Centrifugal force created by the turning rotor throws the material through the open rotor on to the granulator compartment wall (composed of a screen and the stator blades) of the granulating compartment. Here, it gets ground between the rotor and stator blades into cleanly cut, almost dust-free granules.
Flakes from the ground bottles are rapidly extracted through a large non-rust screen encompassing the cutting chamber using a powerful, integrated vacuum extraction unit. The brief dwell time thus achieved implies that flakes are not subject to any thermal stress. Also, specific energy consumption is low, cutter blades sustain very little wear and throughput is exceptionally high.
Contact: Nuga AG, Balgach, Switzerland. Tel: +41 (71) 7200 040; Fax: +41 (71) 7200 045
Recycling waste plastics
| In the United Kingdom, a grant has been awarded to the University of Edinburghs chemical engineering department to help develop the first demo-scale polymer recycling plant for processing plastic wastes. This facility will be based on technology developed by an industrial group led by BP Chemicals Ltd. The process converts mixed waste plastics from municipal and industrial wastes into a heavy liquid suitable for use either as petroleum feedstock or in making ethylene and propylene, the building blocks of mulch plastics production. Grant for the demonstration facility has been provided by BP Chemicals Ltd., and Engineering and Physical Sciences Research Council.
An accurate scale model of the proposed reactor vessel will be used to study the design of a gas distributor for the bed, and the movement of polymer particles within it.
Contact: Dr. Don Glass, United Kingdom. Tel: +44 (131) 6504 860; Or Communications and Public Affairs, University of Edinburgh Centre, 7-11, Nicolson Street, Edinburgh, Scotland EH8 9BE, United Kingdom. Tel: +44 (131) 6501 000.
Metallurgical process for electronic wastes
| Hydromex Umwelttechnologie of Germany is offering a new process to handle waste disposal problems of the electronics economy in line with current economical and environmental needs. The Hydromex process, which is patented, enables reprocessing of electronic wastes into new products. It begins with the manual separation and sorting of all key compounds. The following steps are mechanical shredding, and the segregation of metallic and other residues. Metals are recovered by electrolysis or precipitation and sold to refineries. Non-metallic parts are converted into energy briquettes or building material. Notable benefits of this process are:
Recycling process for electronics junk
| HMR, a multinational firm based in the United States, transforms hi-tech junk PCs, TVs, cell phones and other electronic equipment into marketable commodities, extending the life of electronics and keeping them from posing problems in the landfill. The CRT recycling process commences on a disassembly line. Recyclable plastic or wooden case, metal chassis, yoke, PC board, wire and metal strap are separated from the CRT. These materials are sorted for individual commodity sales. The resulting product is a whole glass tube (impregnated with lead) with an internal metal frame. CRTs are then loaded on to a conveyor system that leads into the CRT crusher, a self-contained unit that allows for easy transportation, total weather protection, dust containment and complete air filtration. The crusher can process 100-150 CRTs per hour, or over 15 tonnes per day.
Once CRTs enter the crusher, they drop into a rotating hammer mill. Hammers hit the glass, causing the CRTs to implode into pieces of glass and metal. A magnet pulls metal from the mix and a screen is used to sift the glass to obtain the desired size. Metals and crushed glass are separately discharged at the bottom of the system into containers for shipment. lead-contaminated glass is shipped to a primary lead smelter, which uses the glass as a fluxing agent in processing raw lead ore. Lead from the glass becomes part of their end product, which is sold for use in manufacturing of products such as new CRTs, X-ray shielding, bullets and batteries.
HMR sells virtually all the materials reclaimed from electronics. Circuit boards are eventually ground up and smelted. Gasses released during this process are captured and the resulting metals lead, tin, gold, and palladium sold. Plastics are grouped by and baled by colour and sold to plastics recyclers. Steel is sold to a local metal recycler, and wood from older television cabinets is chipped for use as biofuel.
Recycling used TVs
| The United Kingdom-based Shore Recycling is recycling cathode ray tubes (CRTs) using innovative laser technology to separate glass. The new cutting-edge laser separation technology from Proventia, Finland allows for excellent segregation of funnel and panel glass fractions. Shores CRT reprocessing facility handles over 350,000 CRTs a year and is licensed by SEPA to receive and treat all products listed under the Waste Electrical and Electronic Equipment (WEEE) directive. Mr. Malcolm Todd, Commercial Director of Shore Recycling, stated that the laser technologys accuracy helps achieve a recycling rate exceeding 98 per cent.
Recycling electronic and cable scrap
| Gestfin Ltd., Russia, offers a system for recycling electronic and cable scrap. The plant incorporates slide elevators, hammer crushers, vertical bucket elevator, drum screen, static electric separator, magnet separator, ventilation aggregate and rotor knife grinder. It can process 5 t/h of scrap; metal granules can be further processed in another system into useful products.
Contact: Gestfin Ltd., 1952989, Saint Petersburg, Uliza Bieloruskaya 6 Co. 2, Russia.
Recovering metals from electronic waste
| Haber Inc., the United States, has designed an electronic waste metals recovery system to extract silver, gold and copper at efficiencies exceeding 99 per cent in less than 3 h. The eco-friendly procedure can produce compounds of greater value than the base metals themselves. The company is planning to set up an Industrial Metals Reclamation Division within its Emerging Technologies Division, which would be responsible for all work in this area and will further expand the systems capabilities.
Contact: Mr. Peter R. DAngelo, Haber Inc., United States of America. Tel: +1 (781) 6432 727.
PERSISTENT ORGANIC POLLUTANTS
Dioxin elimination in waste incineration
| Hitachi Zosen Corp., Japan, offers a comprehensive exhaust gas/ash treatment system to efficiently remove toxic gas and dust. It comprises the following equipment.
Residues/fly-ash generated in the above flue gas treatment system contains toxic substances such as dioxins and water-soluble heavy metal compounds. Fly-ash is heated up to 350-450C for an hour in very low oxygen and then cooled down to about 60C promptly. Dioxins are thus decomposed and eliminated. This system operates automatically, without an operator. For stabilizing heavy metals, fly-ash is mixed and kneaded with moistening water and chemical agent in a twin-axle type kneading unit specially designed for this purpose. Water-soluble heavy metals react with the agent and are converted into insoluble compounds.
Foaming water glass for dioxins control
| Removal of hydrogen chloride (HCl), an acidic air pollutant emitted from facilities incinerating municipal or industrial wastes, is necessary to reduce dioxins emissions as well as to avoid air pollution. The use of calcium hydroxide (CaOH2) as a dry sorbent to remove HCl from flue gas leads to increased pH and fly-ash generation. A research team at Kanazawa Institute of Technology, Japan, reports to have developed foaming water glass (FWG) as a new wet sorbent for injection in a cooling tower to remove HCl while simultaneously suppressing dioxins formation. FWG, a kind of sodium silicate hydrate, is characterized by its special property to form a foam. When the FWG solution is sprayed into a hot wind, microfilm or micro-balloon of sodium silicate is formed. As such, FWG contacts with flue gas over a wide area and higher reaction efficiency is achievable.
Tests were performed by incinerating polyvinyl chloride (PVC) with FWG in air as well as in three industrial incinerators, where FWG was diluted in water and sprayed into flue gas, just after the combustion chamber. Results show that the amount of HCl emitted from 0.5 g of PVC dipped with 0.5 g of FWG was 0.116 g as against 0.164 g with PVC only. Also, FWG removed HCl while lowering dioxins formation to a large extent in the incineration plants, each with different capacities. Researchers conclude that FWG can be utilized instead of CaOH2 to control HCl and dioxins emissions. Furthermore, no extra equipment is required other than a cooling tower since FWG is injected with cooling water.
Contact: Mr. Isao Tsuyumoto, The Kanazawa Institute of Technology, Nonoichi, Ishikawa, Japan.
New process to treat landfill leachate
| Ataka Construction and Engineering Co. Ltd., Japan, is offering Radical Clear, a landfill leachate treatment procedure to handle contamination by dioxins. The key technology for dioxins removal is so-called AOP, advanced oxidation by means of hydroxyl radicals produced through chemical reaction between ozone and hydrogen peroxide. Hydroxyl radicals, known to be the strongest oxidant, attacks chlorine elements to quickly decompose dioxins. UV radiation could also be applied to enhance AOP occasionally. Notable features include:
Radical Clear process involves the following stages: Calcium removal Denitrification Heavy metals removal, dioxins and COD UV disinfection. Potential applications of this process include landfill leachate treatment, treating wastewater at municipal refuse incineration plants and industrial effluent treatment.
Remediating PCB-contaminated soils
| Sonic Environmental Solutions Inc., Canada, has developed a mobile on-site process to effectively remediate soils polluted by polychlorinated biphenyls (PCBs) without any detrimental impact on the environment. The Sonoprocess is based on the ability of a sonic generator platform technology to deagglomerate soil and enhance chemical reactions. This relatively straightforward technology can be set up anywhere in the world to effectively and cost-efficiently treat hazardous wastes and minimize liability.
A low-frequency generator applies very intense audio frequency energy to chambers mounted on each end of a vibrating bar or even to fluids in contact with the chambers. The vigorous agitation can be used to grind particles, effect rapid gas-liquid mass transfer, emulsify fluids and, in most cases, also enhance chemical reaction rates. The sonic generator has a power range at least 10 times greater than that feasible by energy intensive industrial mixing units. In this configuration, contaminated soil is first mixed with a solvent. Sonic energy is applied to the mixture, agitating it to such a degree that it breaks up the soil. This movement extracts PCBs from the soil-solvent slurry and suspends them in the solvent. The solvent is then treated again, using the sonic generator to chemically eliminate PCBs. Thus, soil that can be used as clean industrial backfill and other materials that can be reused can be obtained. Chlorine component of the PCB is rendered into harmless salt while the main by-product, spent solvent, can be used as a low-grade fuel. According to URC Canada Inc., the Sonic process can easily reduce PCBs contamination to less than 50 ppm even as low as 2 ppm is feasible and exhibit accelerated conditioning, pacification as well as carbonation of fly-ash.
Trapping mercury and dioxins from waste incinerators
| Powdered activated carbon (PAC) offered by Norit Nederland B.V., the Netherlands, is utilized to ensure efficient removal of toxic dioxins, mercury and other trace elements found in flue gases from incineration furnaces. This simple, extremely economic, safe and easy-to-use technology can be integrated into new and existing flue gas treatment systems. PAC is blown or drawn into the flue gas flow. It adsorbs dioxins and mercury and is then removed either by bag filters or electrostatic precipitators. Removal efficiencies up to 99.9 per cent for dioxins and 98 per cent for mercury are feasible.
Contact: Norit Nederland B.V., P.O. Box 105, Nijverheidsweg Noord 72, 3800 AC Amersfoort, The Netherlands. Tel/Fax: +31 (33) 4648 911/4617 429
Removal of dioxins
| Daewoo E&C Co. Ltd., the Republic of Korea, has developed dual bag filter (DBF) procedure for removing dioxins found in flue gas from MSW incineration facilities. DBF system is an advanced activated carbon injection treatment technology used with a single bag filter system. The DBF unit comprises two filter bags, in series. Dusts (e.g. fly-ash, SDA dry products) along with solid phase dioxins attached on dust particles are captured in the first bag filter. Gas phase dioxins are absorbed by activated carbon introduced at the entrance of the second bag filter. Separation and recycling activated carbon from the second bag filter enables the DBF system to save on activated carbon powder by up to 50 per cent.
Contact: Daewoo E&C Co. Ltd., 60, Songjuk dong, Jangan gu, Suwon city, Kyunggi do, Republic of Korea. Tel: +82 (31) 2501 100; Fax: +82 (31) 2501 131
| Amstar Envirochem Inc., the United States, has developed an exclusive chemical process that eliminates hazardous polychlorinated biphenyls (PCBs) efficiently, quickly and safely from surfaces. PCB compounds are destroyed at ambient temperatures by a series of chemical reactions that strip chlorine atoms from the benzene ring structure, leaving a non-hazardous fluid. The process ability to eradicate PCBs has been tested on-board decommissioned naval vessels. Up to 99.9 per cent efficiency has been achieved on all treated components.
Comparing EPA estimates of total PCBs awaiting remediation and the total spent to date on remediation, less than 1 per cent of the total available PCB remediation market has been addressed.
Contact: Mr. Steve Mitchell, Amstar Envirochem Inc., United States of America. Tel: +1 (724) 2300 345
| Peter Wilkinson and Co. Pty. Ltd., Australia, is offering solvent recovery units, which enable reuse of waste solvent thinners. Through the process of distillation, solvent recovery systems convert paint-contaminated solvent into a clean and reusable solvent suitable for use in a variety of applications within the vehicle refinishing industry. The system being offered can process 25 l of waste thinners in about 4 h at a recovery rate of around 90 per cent. The recycled solvent is of a quality suitable in the following processes and applications:
Waste thinners are emptied into a 25 l capacity holding tank lined with a heat-resistant plastic bag. Heat is transferred to the waste solvent through a coiled heating element that surrounds the holding tank. At operation temperature, the solvent boils and begins to evaporate. The vaporized solvent is passed through a condenser where it is cooled by a fan and converted into liquid. At the end of the distillation cycle, a semi-solid to hard crystalline residue, primarily comprising paint pigments, remains in the holding tank. The solidified waste can be disposed of in landfills.
Automatic vacuum distillation units
| The United Kingdom-based omnitec UK Ltd. offers two fully automatic vacuum distillation units for solvent recovery. Vakutec-50 incorporates a 50 l distillation vessel while the Vakutec 200 uses a 225 l vessel. Level controllers in the electrically heated vessels limit the addition of solvent and regulate the continuous recovery operation. Operation of these explosion-proof systems is by distillation under vacuum, thus assuring mild distillation at relatively low temperatures. Solvents can be recovered up to a boiling point of 220C. A few salient features of these systems are listed below:
Waste reduction by solvent recycling
| RMAX, a United States-based foam insulation manufacturer, has set up a solvent recycler to recover spent solvents accumulated from parts cleaning operations. Solvents used for the cleaning operations include hazardous constituents like xylene, methyl ethyl ketone (MEK), acetone and others. Recyclit Model SR80 vacuum solvent recovery system, manufactured by Lenan Corp., has helped RMAX to treat about 272 l/y of waste solvents and save US$300 paid per year as hazardous waste disposal costs. RMAX received grant funding from the Nevada Division of Environmental Protection for installing the solvent recycler.
Waste solvent is placed in a 36 l capacity enclosed metal chamber. The still operates by vaporizing the solvent, leaving contaminants behind in a sludge known as still-bottoms. Vaporized solvent condenses on a refrigerated heat exchanger and is captured in another bucket as reclaimed solvent. The reclaimer can handle 4.5-36 l in a batch and shut off when the solvent is reclaimed. The still can recover up to 95 per cent of the spent solvent. Some solvents are recovered in about 5 h while others may require 10-24 h or more, depending on their boiling point.
Regenerative thermal oxidizer
| Mitsubishi Heavy Industries Ltd., Japan, offers a regenerative thermal oxidizer (RTO) to recover solvents and VOCs. This system has three towers packed with ceramic heat storing material and a combustion room with burner on top of them. A control valve is integrated for gas passage in the lower part of each heat storing tower, which includes preheating, radiation and purge processes that are selected by a timer. In the pre-heating process, VOC gas is pre-heated by passing it through the heat storing material, that stores heat from the exhaust gas in the radiation process. Solvent and VOCs are combusted, oxidized and decomposed in the combustion room.
In the radiation procedure, exhaust gas from the combustion room gives off heat to the heat storing material and is vented into the atmosphere. In the purge process, uncombusted gas pooled at the lower part of the heat storing tower in the pre-heating process is replaced with exhaust gas from the combustion room to prevent any odour that may arise when the pre-heating procedure is switched to the radiation process. A burner installed in the combustion room is utilized either for the initial temperature rise or if decomposition temperature (800-900C) cannot be obtained solely by heat generated by the solvent and VOCs in the raw gas. Notable features include:
Ceramic wool is used as the fire-resistant material in this equipment. It is free of cracks in the event of sudden thermal changes, compared with the conventional castor, and can be used for a longer time with no repair. The plant has a capacity to treat about 1,000-6,000 m3/h of solvents, a VOC removal efficiency of 99 per cent and thermal recovery rate of 85-95 per cent.
Solvent recovery solution
Keller Cresent Co., an advertising agency and commercial printer in the United States, has been using a microwave-based solvent recovery system, developed by MicroChem LLC, to recover waste solvents for reuse. The new system has enabled the company to do away with the older explosion-proof centrifuge and distillation unit used for the same purpose. The firms press cleaning process annually generates over 350 barrels of used shop towels and 55 barrels of used blanket wash. On average, each barrel of shop towels contains 600 shop towels saturated in ink, water and solvent while the blanket wash barrel contains over 230 l of a 50 per cent mixture of water and solvent.
New solvent recycler
ATEC Trans-Tool, the United States, offers StillClean solvent recycler for obtaining pure clean solvent in an eco-friendly manner by recycling dirty greasy solvent. The portable, low-temperature solvent distillation system distills 105 and 140 solvents at a rate of 4.5-5.5 l/h of solvent continuously. The patented system works just like a still and can be integrated with any solvent parts cleaner. It draws in dirty solvent under vacuum, heats it up and the vaporized solvent is passed through a coil cooling system where it condenses back into its original crystal clear state. Waste by-products are contained and left behind in the distillation tank.
Treating spent dye-bath from textile mills
| Researchers at the University of Massachusetts, the United States, have tailored new solutions to treat spent dyebath from textile mills, which is one of the highest-rated contaminants among all industrial sectors. The dyebath from textile mills contains heavy metals, toxic solids and is notoriously high in colour content. With funds provided by the National Environmental Technology Institute, as well as private contribution, Prof. Sarina Ergas and Prof. David Reckhow have developed treatment methods with the concept of zero-discharge.
To ensure economic feasibility, the criteria centered on an inexpensive and efficient process to make 75 per cent of the water recyclable. After three years and evaluation of eight different methods, two were found to be satisfactory electrochemical oxidation, which passes the spent dyebath through an electrolytic cell, and ozonation, in which an industrial-strength ozonator is applied to the used dye water.
In-house effluent treatment model
| Sri Renuga Textiles Ltd., India, has unveiled a total effluent treatment solution aimed at complying with the zero discharge rule stipulated for the textile wet-processing industries. The new Flash-tech enviro systems, an improvised treatment process of evaporation technique module, offer less breakdown ratio compared with similar evaporator-based treatment plants currently available. Moreover, this system provides higher effluent treatment efficiency by consuming less power and steam. While 90 per cent of effluent water is recovered for reuse, 99 per cent of the salt used for recycling is reclaimed. Improved heat transfer system and additional controls prevent salt deposition, a major stumbling block that was not addressed in earlier models.
Wet air oxidation of refractory organic compounds
| Organic compounds are classified as refractory when they are poorly biodegraded and/or exhibit a low value for the ratio of biological oxygen demand vis-a-vis chemical oxygen demand (BOD:COD). In the United States, USFilter offers Zimpro wet air oxidation (WAO) system to treat industrial wastewaters and for in-process applications. This process can also be used for sludge treatment and destruction applications.
Wet oxidation is the oxidation of soluble or suspended components in an aqueous environment utilizing oxygen as the oxidizing agent. When air is used as the source of oxygen, the process is referred to as wet air oxidation. Oxidation reactions occur at temperatures of 150-320C and at pressures of 153-3,200 psi. The required operating temperature is determined by the treatment goals and the ease or difficulty in oxidizing the components. Higher operating temperatures need higher pressure to maintain a liquid phase.
The archetypal WAO system is a continuous process using rotating equipment to pressurize both the feed stream and air to the system working pressure. Heat exchangers are routinely used to recover energy from the reactor effluent, which is then utilized to pre-heat the feed/air mixture getting into the system. Auxiliary energy, usually steam, is essential for start-up and can provide heat if required. The reactor vessel offers residence time at the desired operating temperature, enabling propagation of the oxidation reactions. Since the oxidation reactions are exothermic, sufficient energy may be released and recovered to allow the WAO system to operate without any additional heat input.
Removing colour from textile effluents
| A cost-effective bio-adsorption process has been developed to remove colour from textile effluents. BIOCOL process was developed in the United Kingdom by Applied Technology Unit at QUESTOR Centre of Queens University in cooperation with the British Textile Technology Group. Under the aegis of a DTI BIO-WISE Demonstrator project, a BIOCOL plant has been established at John Hanna Ltd., a firm that bleaches, dyes and finishes material for the apparel market. Benefits now being enjoyed by the company include:
The BIOCOL plant uses filter cartridges that are packed with a special carbon-based material, coated with patented microbes, which degrade the dyes into non-toxic colourless products. This system has been specifically designed to treat the concentrated spent reactive dye liquors released at the end of the cold pad batch dyeing process. The plant is typically just 20 per cent the size of conventional technologies since the dyes are treated at source prior to dilution with any other non-coloured effluent streams. The pilot demonstration plant at John Hanna Ltd. has achieved over 95 per cent colour removal efficiency.
Treating textile dye wastewater
| In India, a team of researchers has developed an electrochemical bipolar disc stack reactor, utilizing RuO2 coated on titanium as anode and titanium as cathode, to treat wastewaters from textile mills. This electrochemical oxidation technique has been evaluated. Sodium chloride present in the effluent was used as supporting electrolyte. Operating parameters such as current density, reservoir hold-up and electrolysis time were investigated for maximum COD reduction and other relevant criteria like current efficiency and power consumption per kilogram of COD removal were calculated.
A higher flow rate and lower reservoir hold-up resulted in improved COD removal. The applied current density was also found to have considerable impact on COD reduction. A suitable mathematical model has been proposed to illustrate the relationship between basic parameters. Pseudo mass transfer efficiencies have also been ascertained for different experimental conditions.
Treating wastewater rich in heavy metals
| Russias Ural Process Engineering Co. (UPEC) has developed cost-effective treatments for processing industrial wastewater, specifically removing heavy metals, together with the United States-based Fenix Technology International Inc. and Brookhaven National Laboratory. A novel approach utilizing patented electro-coagulation process is cost-effective and easy to implement and maintain. The technology could be structured to suit individual requirements. Chemistry of the process depends on the treated wastewater parameters, where the process pH is a defining factor and can be altered with reagents for a specific value needed for an effective process.
Basic materials used in the process are mechanical metal scrap, e.g. iron, aluminium, etc. Modular units for cementation and electro-coagulation of extracted metals are used for cleaning wastewater polluted by heavy metals. The units are simple to fabricate, but various capacities require specially designed modules. To treat 50-100 m3/h of wastewater containing heavy metals, a cemento-coagulator known as labyrinth is employed in the form of a tank with labyrinth partitions. Containers with metal scrap are placed inside the labyrinth, depending on the content of treated water. For treating 0.5-50 m3/h, a small volume cemento-coagulator is recommended. A metal or plastic container acts as labyrinth filled with metal shavings.
Contact: UPEC Ltd., Sheinkman Street, 20, Yekaterinburg, 620014 Russia. Tel: +7 (3432) 710 315/710 618/710 737;
Treating residual dyehouse liquors
| Researchers at the Institute of Biochemical Engineering in Germany have studied a combined biological and chemical technology to purify residual dyehouse liquors containing reactive azo-dyes. This procedure involves anaerobic dye-cleavage, aerobic mineralization of cleavage products, and the decolourization and partial oxidation with ozone of traces of dye residuals. The treatment process helps increase the quality of the treated split flows for recycling purposes as well as the dye capacity of the textile mill, while simultaneously minimizing operating costs. A patent for this process is held in association with Dr.-Ing Bernd Diering GmbH.
A technical treatment and recycling plant has been set up at a medium-sized textile mill, which produces on an annual basis twelve million metres of coloured fabric and wastewater of 330,000 m3.
Contact: Mr. Peter Peckedrath, Industrie- und Handelskammer, Germany. Tel: +49 (531) 4715 281.
Evaporators treat industrial effluents
| In the United States, Severn Trent Services is offering Samsco line of wastewater evaporators and vacuum distillation systems. Samsco range of equipment includes immersion-heated evaporators with an elevated serpentine heat exchanger, which permits solids to accumulate below the heat exchanger. This exclusive evaporator configuration utilizes an open coil, round/tubular design, so that solids fall harmlessly past the heat exchanger.
A different firm, RGF Environment Group, offers thermo-oxidizer wastewater evaporators. The RGF Thermo-Oxidizer evaporator features RGFs dry chamber flash evaporation technology. Thermo oxidation eliminates corrosion and sludge problems. Mr. Len Graziano, President and CEO of Severn Trent Services, states that Samsco line represents the industry standard for wastewater evaporator design and production. RGFs flash evaporation technology is complementary to ours and enables us to offer alternative, quality evaporation solutions to users.
AIR POLLUTION CONTROL
| RAPRENOx technology developed in the United States has the potential to significantly lower NOx emissions from gas or diesel turbines used in offshore operations. The patented process is non-toxic and considered an effective means to achieve Clean Air Act NOx limitations offshore. RAPRENOx uses isocyanuric acid, created by the decomposition of cyanuric acid, a non-toxic, non-inflammable, commercially available solid material. Gaseous isocyanuric acid is added to the exhaust stream whereby the NOx is reduced to N2, H2O and CO2. Cyanuric acid is safe to store and use around personnel in an offshore platform environment.
Contact: Mr. Curtis Carey, Minerals Management Service (MMS), Chief, Public Affairs, 1849 C Street, N.W. Washington, D.C. 20240, United States of America. Tel: +1 (202) 2083 985.
Carbon towers used to eliminate odours
| Aromatrix Technologies Pte. Ltd., Singapore, offers pre-engineered pelletized activated carbon adsorption systems to effectively eliminate residual odours from municipal and industrial processes. They can even eliminate residual organics from exhaust streams and other difficult-to-treat odours. Designed to provide cost-effective odour removal, with ease of installation and operation, this system is characterized by its excellent corrosion resistant traits, continuous treatment, elimination of the need for chemicals and storage, and minimal operator attention.
AroBIOS series of scrubbing units incorporate biological trickling filters for odorous air treatment. Field tests at several large municipal wastewater treatment plants have proven effective removal of odorous gases. Key features include:
Chemical scrubbers are especially efficient in eliminating odours, gases and vapours. These units basically work on two fundamental principles, mass transfer and impaction. The contaminants are transferred from the exhaust stream to the liquid phase within the scrubber, where they are absorbed and neutralized. Design flexibility in constructing the vessel, packing material selection and depth sizing allow each system to be engineered to meet specific performance requirements. Some of the key features have been listed in the box below.
| Crystal Industrial Syndicate, India, offers wet scrubbing systems, which are either ejector Venturi scrubbers or packed towers or combinations of ejector Venturi scrubbers with packed towers. The ejector Venturi scrubber provides both the functions of scrubbing and creates system draft. It utilizes the energy of the scrubbing liquid to effectively entrain and remove noxious gases, odours, particulates, fumes and dusts from the flue gas. Gaseous pollutants and odours are removed by absorption and/or chemical reaction between the gases and scrubbing liquid. Apart from providing effective scrubbing, the ejector Venturi scrubber also gives rise to an air-moving and/or static pressure-boosting capability for the system.
The packed tower scrubber is a low-energy, contact-bed type wet unit for gas absorption, gas cooling and stripping of contaminants from process liquids. These scrubbers are specifically engineered to provide highest efficiency with lowest power consumption, without sacrificing performance ability.
The company also provides high-energy Venturi scrubbers designed for the removal of sub-micron fumes, mists and particulates. Also, multi-Venturi packless (MVP) fan-driven emergency chlorine gas scrubber can be supplied.
Contact: Crystal Industrial Syndicate, Off. No. 6, Plot No. 2, Phase 2, Sector 2, Nerul, Navi Mumbai 400 706, Maharashtra, India. Tel: +91 (22) 2772 7410/6188; Fax: +91 (22) 2772 6929
Flue gas treatment system
| Ebara Corp., Japan, offers a process for treating flue gas streams using electron beams. This dry technique processes flue gas generated by the combustion of fossil fuels. It simultaneously performs denitration and desulphurization, preventing atmosphere-polluting emission of NOx and SOx. Desulphurization and denitration are carried out by mixing flue gases with gaseous ammonia and then irradiating with electron beams. During irradiation, highly chemically reactive free radicals are generated within the emissions. SOx and NOx present in the flue gas react with these radicals and are converted first into sulphuric acid and nitric acid, and subsequently into aerosols of ammonium sulphate and ammonium nitrate. The aerosols are later extracted using an electrostatic precipitator.
The totally automated and highly efficient system can be applied for treating a variety of gases containing NOx and/or SOx. Notable features of the process which comprises a spray cooler, process vessel and a by-product collector include:
Ceramic reactor to purge NOx
| Advanced Manufacturing Research Institute of Japan has developed technology to produce a ceramics reactor, which incorporates a novel feature driving a self-consistent electrochemical reactor through thermoelectric power generation using exhaust heat. This technology is expected to further accelerate the development of ceramics reactor and relevant sensors to control electrochemical reactions without requiring outside power supply and any other auxiliary equipment.
For demonstration purposes, an integrated module has been devised by combining a power unit made of 18 pairs of newly developed thermoelectric power generating ceramic devices connected in series, along with an electrochemical reactor that consists of 5 cm2 8Y-ZrO2 (8YSZ) ceramic board and electrodes with high selectivity for NOx reaction. With this system, an experimental test was undertaken by creating a temperature difference by feeding mixed gas consisting of 400 ppm NOx and 4 per cent O2 heated to 600C. It was found that about 20 per cent of NOx is degraded continuously at the electrochemical cell with power generated by thermoelectric ceramics (1.5 V, 35 mW).
NOx burner for industrial furnace
| Kobe Steel Ltd. of Japan offers a simple low-NOx burner. Suitable for application in existing furnaces, the system lowers NOx concentrations to less than half that obtained using a conventional burner.
In this system, slow combustion has been embraced as a heating efficiency measure by not allowing mixing of fuel and air during the initial stage of combustion. The direction of fuel injection is at an angle to the air stream axis and mixing of fuel and air in the primary combustion zone is limited. As such, a local high temperature region cannot develop. Fuel that is not burned in this zone gradually mixes with air not used in the initial stages and as such, combustion is completed. It is therefore possible to achieve uniform
combustion. The drop in both the maximum flame temperature and local oxygen partial pressure helps suppress thermal NOx and fuel NOx and thus, the NOx value is drastically reduced. Contact: Kobe Steel Ltd., Japan.
Scrubber removes various pollutants
| Airchem Technologies Pte. Ltd., Singapore, offers SC fume scrubbing system whose design is based on counter-flow for vertical geometrics and cross-flow for horizontal geometrics. The system is constructed utilizing reinforced fibre glass with vinyl ester resin, which has strong chemical resistance. It can treat with over 95 per cent efficiency exhaust gases from various industries such as food processing, metal finishing, chemical mixing, semiconductor, disk drive, power plants and pharmaceutical facilities. Pollutants that can be treated include inorganic acids (H2SO4, HCl, HF, HNO3, chromic acids and H2S), inorganic alkalies (NaOH, KOH, NH3), organic acids (acetic acid), odour (malodour, H2S), organic alkalies, gases (Cl2, SO2, NOx) and alcohol.
Contact: Airchem Technologies Private Limited, 10, Changi South Lane #05-01,Singapore 486162. Tel: +65 6358 4898; Fax: +65 6356 7592