Integrated biological and electrochemical oxidation
Scientists from Aquabiotec GmbH, Germany, have developed an innovative technology for industrial wastewater treatment. The main focus of the Aqua-Biomant® process is transformation of persistent organic compounds (bio-recalcitrant COD) into a biodegradable fraction, followed by high-efficiency biological elimination using specialized bacteria. The Aqua-Biomant process integrates two treatments: aerated biological upflow filtration, and electrochemical oxidation technique using boron doped-diamond electrodes. The advantages of the process are high-efficiency COD removal with reduced energy consumption combined with low total residence time.


Contact: Mr. A. Rüdiger, Aquabiotec GmbH, Maria-Goeppert Str. 1, D-23562, Lübeck, Germany.


Source: www.iwaponline.com
Wastewater treatment with fixed-bed circulation reactor
Fraunhofer IGB, Germany, is testing a fixed-bed circulation reactor in which the fixed bed is partially recirculated from time to time, allowing continuous and trouble-free operation. The wastewater flows through the particle bed from bottom to top and its contents get degraded. To recirculate the particles, the fluid is removed from the top of the reactor and is injected through a nozzle at the bottom of the conveying pipe. By doing so, the particles are hydraulically conveyed upwards and are cleaned owing to the turbulence.


The design of the reactor depends upon the flow properties of the fixed bed packing. The particles differ in the following characteristics: availability, mechanical stability, immobilization of micro-organisms, flow properties and conveying properties. The flow properties of the particles are identified based on the theory of flow of bulk solids. With respect to the design of fixed bed reactors, the following terms are determined: the slope angle of the hopper and the critical area at which no blocking of the flowing particles occurs. Prototypes of the reactors are in operation at industrial companies for assessment.


Contact: Dr. Werner Sternad, Umweltbiotechnologie und Bioverfahrenstechnik, Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstrasse 12, 70569 Stuttgart, Germany. Tel: +49 (711) 970-4110; Fax: +49 (711) 97 04 200


E-mail: werner.sternad@igb.fraunhofer.de


Source: www.igb.fraunhofer.de
Advances in tube-type fine bubble diffuser design
A majority of wastewater treatment plants around the world use submerged diffused aeration. Because these systems are for the most part submerged in sewage, they must be highly reliable. Stamford Scientific International (SSI), based in the United States, has introduced a new technology that meets this reliability level.
Because of their small size, disc diffusers have less forces acting on them underwater than do larger cantilevered tube diffusers.


Moreover, the method of manufacturing a disc membrane allows great flexibility in rubber compounding and moulding, which can result in a high-quality, tear-resistant and shrink-resistant part. Disc-type fine bubble membrane diffusers have thus gained a name as a highly reliable method of aeration. Limitation of moulding methods has restricted the manufacture of tube diffusers. Therefore, tube diffusers have not gained the same excellent record of longevity and reliability as have disc diffusers. Shrinkage, tearing and stretching do occur with tube membranes.


SSI has developed a way to compression-mould membranes for fine bubble tube diffusers to give them the same advantages as disc diffusers. This method allows the use of less plasticizer in the compound, and the final product shows excellent tear resistance. The diffusers have a plastic diffuser body, made of high temperature resistant and environmentally friendly ABS, with a quick connect type fastener to pipe.


Contact: Stamford Scientific International Inc., 4 Tucker Drive, Poughkeepsie, NY 12603, United States of America. Tel: +1 (845) 454 8171; Fax: +1 (845) 454 8094


E-mail: info@stamfordscientific.com


Source: www.prleap.com
Combined system for wastewater with recalcitrant pollutant
In Spain, scientists from Plataforma Solar de Almería-CIEMAT and Universidad de Almería have described a wastewater treatment system having two advanced oxidation processes (AOPs) – ozonation and photo-Fenton – in combination with a pilot aerobic biological reactor. The system was employed for treating industrial non-biodegradable saline wastewater (TOC ~ 200 mg/litre) containing a-methylphenylglycine (MPG), a bio-recalcitrant compound, at a concentration of 500 mg/litre.


Ozonation tests were performed in a 50-litre reactor with constant inlet of 21.9 g/m3 ozone. Solar photo-Fenton tests were carried out in a 75-litre pilot plant made up of four compound parabolic collector units. The catalyst concentration used in this system was 20 mg/litre of Fe2+ and the H2O2 concentration was kept in the range of 200-500 mg/litre. Complete degradation of MPG was attained after 1,020 minutes of ozonation, while only 195 minutes were required for photo-Fenton.


Biodegradability enhancement of the saline wastewater (>70 per cent biodegradability) was confirmed. Biodegradable compounds generated during the preliminary oxidative processes were biologically mineralized in a 170-litre aerobic immobilized biomass reactor. The global efficiency of AOP/biological combined systems was 90 per cent removal of an initial TOC of over 500 mg/litre.


Contact: Dr. Isabel Oller, Plataforma Solar de Almería-CIEMAT, Carretera Senés, KM 4, 04200 Tabernas, Almería, Spain.


E-mail: isabel.oller@psa.es


Source: www.iwaponline.com
New wastewater treatment technology
SSI, a member of the international consultancy and engineering group DHV of the Netherlands, has introduced an advanced and compact wastewater treatment plant in South Africa. The Nereda technology uses aerobic sludge granules, which settle much faster than the small and sometimes flaky sludges that are normally seen in conventional wastewater treatment plants. The technology can treat both domestic and industrial wastewaters. The final effluents conform to European Union standards.


Unlike the conventional wastewater treatment plants that make use of secondary sedimentation tanks for the biologically activated sludge process, the Nereda process separates the sludge from the treated wastewater inside the reactor tanks. The sludge concentrations and the total quantity of purifying bacteria in the reactor are significantly higher with Nereda technology, which was developed at the Delft University of Technology in the Netherlands.


Compared with conventional plants, the technology is claimed to offer energy savings as high as 30 per cent over and 20-40 per cent lower capital costs associated with construction. No chemicals are needed, and the plant is simple to operate because of extensive automation.


Source: www.engineeringnews.co.za
Electro-coagulation of effluent
TI Anode Fabricators, India, has developed the TiChlor-EC system, to increase colour removal rates from water effluents at low capital investment and reduced operating costs. TiChlor-EC is an electro-coagulation process. Its benefits include sludge minimization, treatment of multiple contaminants, disinfection of effluent and low maintenance costs.


The process can treat effluent from textile and dye industry, food processing industry, coal mines and chemicals industry for operations such as:
 
  • Pre-treatment for reverse osmosis, ultra filtration and nano-filtration;
     
  • Recirculation of process water and rinse water;
     
  • Pre-treatment of boiler water;
     
  • Metal recovery;
     
  • Radio isotope removal; and
     
  • Wastewater disinfection.
     

Typically, TiChlor-EC has achieved the following benchmark reductions:
 

  • Bacteria from 110 million (standard plate count) in wastewater to zero focal count;
     
  • Contaminants in oily wastewater from steam cleaning operations, refineries, rendering plants and food processors by 95-99 per cent;
     
  • Dissolved silica, clays, carbon black and other suspended materials in water by 98 per cent; and
     
  • Heavy metals (such as arsenic, cadmium, chromium, lead, nickel and zinc) in wastewater by 95-99 per cent.
     

Contact: TI Anode Fabricators Ltd., 48, Noothanchary, Madambakkam, Selaiyur, Chennai, Tamil Nadu 600 073, India. Tel: +91 (44) 2278 1148; Fax: +91 (44) 2278 1362.


Source: www.tianode.com

Effluent with heavy metals treated using iron oxide catalyst
The Korea Institute of Geoscience and Mineral Research, the Republic of Korea, has received a United States patent on a method for treating acidic (ph ~1.0) wastewater containing heavy metals – Cu, Fe, Ni, Cr or Zn – employing a used iron oxide catalyst. The method consists of: adding the used iron oxide catalyst containing at least 70 per cent magnetite to the wastewater at a weight ratio of 1:0.05; stirring the wastewater mixed with the catalyst in a stirrer at 60 rpm for 15 min; and effecting a solid-liquid separation, using a magnet for adsorption and removal of the heavy metals.


The catalyst used in the method is a strongly magnetic iron oxide catalyst used in the synthesis process of styrene monomer. The method is suitable for wastewater containing heavy metals such as metal plating wastewater or mine backwater.


Source: www.freepatentsonline.com