Prof. Wei-xian Zhang, a professor of civil and environmental engineering at Tongji University, China, has concluded a five-year research project in which he and his colleagues used about 900,000 kg of scrap iron to detoxify pollutants in industrial wastewater. The project, carried out in Shanghai, was the largest in history to use iron in an environmental application. The iron, called zero-valent iron (ZVI) because it is not oxidized, was obtained as turnings or shavings from local metal processing shops at scrap value.

The ZVI project began with small, bench-top experiments in the laboratory that used a total of 40 kg of iron to treat toxins in solution. It graduated into a pilot test using a copper-activated iron to pre-treat wastewater in small pharmaceutical, chemical and materials companies. The wastewater had previously been treated with micro-organisms alone. ZVI augmented and improved this remediation method.

Following the pilot test, a full-scale treatment reactor, capable of processing about 60 million litres per day of wastewater, was constructed ad connected to the biological treatment plant. The addition of ZVI treatment to the traditional biological methods of wastewater treatment resulted in notable improvement in reducing pollutant levels, according to Prof. Luming Ma, who directs the National Engineering Research Centre for Urban Pollution Control in Tongjis College of Environmental Science and Engineering. The biological oxygen demand (BOD) removal rose from 76 to 87 per cent. Improvements were also recorded with the removals of nitrogen (13 to 85 per cent), phosphorus (44 to 64 per cent), and colours and dyes (52 to 80 per cent).

Toxic compounds in industrial wastewater, many of which are synthetic organic chemicals, are attracted to the surface of the iron, where they share electrons with the iron and are degraded and detoxified. The ZVI, which gets oxidized during this exchange, has a useful lifetime of about two years in the treatment process. The ZVI is chemically similar to iron-based nanoparticles invented by Prof. Zhang that are now widely used in North America to clean decontaminated soil and groundwater.

Source: www.sciencedaily.com

Basin Water Inc., the United States, recently unveiled its newly acquired Envirogen environmental treatment products. In the area of water treatment, Envirogen products include fluidized-bed bioreactors, membrane bioreactors and suspended carrier reactor systems.

Envirogen bioreactor systems are designed to handle a broad range of contaminants, flow rates and contaminant concentrations. At the high-flow end of the spectrum, Envirogen fluidized-bed bioreactors feature a fixed-film reactor column that fosters the growth of micro-organisms on a hydraulically fluidized bed of media. The fluidized media can provide a biomass inventory of up to 15,000 mg/l, allowing the treatment of high flow rates and relatively high contaminant loadings. Primary applications for this technology include nitrate removal from wastewater.

Envirogen membrane bioreactors combine the benefits of a suspended growth reactor with the solids separation capability of an ultra- or micro-filter membrane unit. The systems are particularly well-suited to wastewater or groundwater streams with difficult-to-treat organics, high contaminant concentrations, highly variable influent compositions or for sites where system footprint is a concern. Envirogen membrane bioreactor applications today include batch chemical plant effluents, landfill leachate, chlorinated solvents in manufacturing wastewaters, etc.

Envirogen suspended carrier reactor systems are integrated, fixed-film moving bed activated sludge biological systems for the treatment of municipal and industrial wastewaters. These systems are suitable for retrofit applications in activated sludge biotreatment installations that are operating at or exceeding design capacity. Contact: Basin Water Inc., 9302 Pittsburgh Avenue, Suite 210, Rancho Cucamonga, CA 91730, United States of America. Tel: +1 (909) 481 6800; Fax: +1 (909) 481 6801; E-mail: info @basinwater.com; Website: www. basinwater.com.

Source: www.marketwatch.com

A Japanese research team has developed a hydrolysis process based on a new complex catalytic method and succeeded in eliminating wastewater during amides production. The team was led by Dr. Toshiyuki Oshiki of the Okayama University Graduate School of Natural Science and Technology.

Amides production by copper catalyst and enzymatic methods require large amounts of water, and consequently produce a large amount of wastewater. For example, hydrolysing acrylonitrile using any of the two methods produce an acrylamide. However, this production process uses water in the molar ratio of 100 water to 1 acrylonitrile. As a result, a large amount of industrial wastewater is produced. Furthermore, thermal energy is lost during the water condensation process, and the transportation efficiency is low because acrylamide is produced as a 50 per cent water solution.

The new catalytic method, in contrast, called dual-function complex catalysis, uses a ruthenium or iridium complex. Water is activated under neutral conditions and nitrile is activated mainly by metal. Hence, the reaction progresses without a solvent under neutral conditions. The hydrolytic reaction proceeds with 1 water to 1 nitrile in molar ratio. The reaction consumes all the water for the production of amide, producing no wastewater. The reaction temperature can be set to nearly 180C, resulting in a faster reaction speed. The target amide can be obtained at a concentration of nearly 100 per cent.

Source: techon.nikkeibp.co.jp

A European research project has succeeded in developing a cheaper treatment system for wastewater from ships, oil refineries and other petrochemical industries contaminated with toxic compounds. The cost is just a tenth that of other commercial tertiary treatments, and the treated water is so clean that it can be pumped safely into the sea without endangering flora or fauna.

The most complete method of treating petrochemicals-contaminated wastewater is through a series of physico-chemical and biological processes. It is complex, requiring a combination of bioreactor, chemical coagulation, granulated activated carbon and sorption technologies. The tertiary stage is the most expensive part of the treatment and can cause problems such as fouling, undesirable bacterial growth and toxic sludge.

We set out to find a stable process which was as cheap as possible, says Professor Viktoras Racys at Lithuanias Kaunas University of Technology, the main project partner in Eureka project Euroenviron Biosorb-Tox. The research group at the universitys environmental engineering department had already developed and tested a new wastewater treatment model on a laboratory scale. The project team came up with an ultra-efficient combination on an industrial scale: the three processes sorption, bio-degradation and filtration in one a reactor. The pollutants are degraded by the micro-organisms created within the reactor, Prof. Racys says.

The system is already functioning at Lithuanian oil company, Nasta. Prof. Racys says, It has a high capacity, processing 160 m³ per hour. The cost is 1 for every 3.5 litres. Effectively it is 10 or 20 times better than what else is available. The pollutant is reduced from 1 g to 0.1 g per litre of water. This surpasses the EU standards and the water can be put straight back into the sea, claims Prof. Racys.


Source : www.sciencedaily.com

A type of algae is being developed to treat wastewater from the mining industry that contains heavy metal and acidic components. It would be the first time algae are used this way, and the developer, Mr. Jamie Miller of Somnium Innovations Pty Ltd., Australia, says that the algae technology was designed for use in acid mine drainage. Acid mine drainage is a massive problem for the mining industry; it is a multi-billion dollar problem economically and an environmental problem and so we are seeing an opportunity in the industry to develop technology to treat this problem, Mr. Millier said. A prototype for the algae technology is expected by the middle of 2009.


Source: www.abc.net.au

Philadelphia Mixing Solutions from the United States, has introduced Momentous Flow^TM  the next generation mixing technology for anaerobic digestion in the wastewater, biofuels and agricultural markets. Compared with standard and egg digester technologies, this mixing system is claimed to offer much faster installation, lower operating and maintenance costs, and efficient generation of reusable energy from methane capture.

Momentous Flow uses a single Z/T = 3.0 axial impeller and no baffles in the upper part of the vessel to create centrifugal force. That force pushes membrane methane bubbles from anaerobic digestion to the centre of rotation, where they quickly coalesce and escape from the liquid into a collection cap. The methane is then harnessed to power digestion operations, significantly reducing or eliminating the need to power the equipment from the grid.

Momentous Flow equipment has a cone-shaped bottom and is much smaller than standard mixing equipment. These design improvements drive down the cost of initial site construction and installation. Its single impeller requires less service time than traditional multi-mixer installations, reducing maintenance and repair costs. Contact: Philadelphia Mixing Solutions, 1221 East Main Street, Palmyra, Philadelphia, PA 17078 9518, United States of America. Tel: +1 (717) 832 2800; Fax: +1 (717) 832 1740; Website: www.philamixers.com.

Source: news.thomasnet.com

Algerian researchers have found that something as ordinary as orange peel could be used to remove acidic dyes from industrial effluent. Synthetic dyes are extensively used by industries including dye houses, paper printers, textile dyers, colour photography, and as additives in petroleum products, explained Mr. Benassa Houcine of the Laboratory of Sorbent Materials and Water Treatment, University of Tlemcen.

The effluents of these industries are highly coloured, and their disposal into the environment can be very deleterious. Their presence in water courses may be visible at concentrations as low as 1 ppm. In looking for an alternative to chemical treatment of wastewater, Mr. Benassa considered a common food industry by-product, orange peel. He tested orange peel as an absorbent for the removal of four acid dyes from simulated samples of polluted water.

The research demonstrates that absorption time depends on the initial concentration of the dyes as well as the chemical structures of the particular dyes being tested, but absorption can occur at just 25C. Strong dyes such as Nylosane Blue, Erionyl Yellow, Nylomine Red, and Erionyl Red were absorbed at 40-70 mg/g of orange peel. Further research is now required to optimize and scale-up the process for the real-world clean-up of dye effluent. This will involve identifying the biochemical
sites in the orange peel to which the dye molecules stick during absorption.

Source: www.hindu.com