Ebara Engineering Review

by Kiyomi ARAKAWA, & Toshihiro TANAKA
The effects of sludge-reducing ozonation conditions on nitrogen in the effluent of an activated sludge process were studied through continuous bench-scale tests. The nitrogen concentration in the effluent and that in the produced sludge were monitored under different ozone injection rates. It was revealed that although ozonation was effective for reducing the amount of excess sludge produced, it increased the T-N in the effluent. The amount of nitrogen in the reduced sludge was found to be almost identical to amount of T-N (most of which was NOx-N) in the effluent. The results of this study suggest the possibility of a nitrification-denitrification process which would enable a large part of effluent nitrogen, produced by sludge reduction, to be removed, also that biological denitrification was practical for sludge reduction in activated sludge processes.

Keywords
Sludge reduction, Nitrification-denitrification process, Ozonation, Nitrogen removal, Activated sludge treatment

by Yusuke TAMARI, Takashi IMAIZUMI, Satoshi ASANO, & Tatsuya HASEGAWA
A new gasification system for the pyrolysis of sewage sludge has been developed. This system features a gasifier for producing product gas for gas engine power generation. A pilot plant, capable of treating 15 tons/day of dehydrated sewage sludge, had been used since 2005 and continuous performance tests (over 3400 hours) had been carried out. The stability and environmental feasibility, as well as its practicality had been proven by the tests. Replacing a conventional sewage sludge incineration plant with this system enables a 25% saving in primary energy consumption and a 65% reduction in the emission of greenhouse gases. The use of this novel system is looked forward to as an effective measure towards the prevention of global warming.

Keywords
Gasification, Fluidized-bed, Sewage sludge, Gas engine, Power generation, Pyrolysis, ICFG, Biomass

by Kohei MATSUNAGA, Takayuki IHARA, Kei MATSUOKA, Kenichi SEMITANI, Tatsuya HASEGAWA, & Takayoshi KAWAGISHI
R&D is underway for a novel ICFG (Internally Circulating Fluidized-bed Gasifier) for converting biomass and wastes into higher calorific product gas. This gas is for use as alternative fuel for power generation and liquid fuel synthesis by industries. A performance test of the ICFG had been done at a test facility for over 6700 hours and results confirmed that it was a feasible system for recovering energy from biomass and wastes.

Keywords
Fluidized-bed, Gasification, Pyrolysis, Biomass, Waste, Energy, Power generation, Liquid fuel synthesis

by Satoshi SEKIZUKA, Hiroshi OKAZAKI, & Sumio SAITO
Wind conditions and power generation were evaluated for two wind turbine generator systems to clarify Weibull distribution effects, namely by changes in shape parameters. The systems had the same nominal rated power but their control methods were different. Shape parameter effects were also studied using measured wind condition data of prototype wind turbines operating at a site.

Keywords
Wind turbine, Wind turbine generator system, Propeller type wind turbine, Power control, Wind speed, Frequency distribution of wind speed, Power performance, Power curve , Weibull distribution, Rayleigh distribution

by Yoshihiro UCHIDA, Toru ISHIDO, & Sakae SHIMIZU
A new vertical pump has been developed and released into the market. The pump's submerged bearing, which constitutes a consumable part, is set below the pump impeller and not inside the pump bowl. This allows inspection on wearing or erosion of the bearing, and exchanging the bearing when necessary, without hoisting the pump. This pump design (patent pending) has revolutionized the maintenance and inspection of vertical pumps and is notably contributing to labor and cost saving.

Keywords
Submerged bearing, Impeller, Discharge bowl, Full-speed stand-by operation at any suction water level, Ceramic bearing, Tungsten carbide sleeve, Brittleness, Axial flow pumps, Mixed flow pumps, Maintenance management

by Shinta KUNITOMO, Kenichi SASAKI, Masao AYUKAWA, & Hisamichi FUJIWARA
A pulsed discharge water-bloom prevention system had been developed for the removal and propagation-prevention of water-bloom (free-floating algae such as Microcystis) in closed-water bodies. This system uses shock waves from electric discharge to specifically collapse gas vesicles inside water-bloom cells, making them sink to the aphotic and low temperature bottom of a water body, thus inhibiting their growth by reducing their activity. Neither cell membranes nor colonies of water-bloom become scattered, resulting in no water pollution. Another feature is that only water bloom with gas vesicles are targeted and effects on other aquatic life are minimized. As treatment effectiveness is not dependant on turbidity elements and water-bloom concentration, it is possible to conduct treatment per miscellaneous matter such as dead leaves and twigs. The system is shaped like a pontoon so it can be easily transported to an area of water-bloom growth, thus enabling its use at dams and inlets of lakes and marshes, as well as in shallow water reservoirs.

Keywords
Algae, Water-bloom, Pulsed discharge, Shock wave, Water treatment, Microcystis, Microcystin, Gas vesicle, Closed water area

by Masayuki KAI, & Satoshi ASANO
A novel internally circulating fluidized-bed gasifier (ICFG), Model TWINRec, has made it possible to efficiently obtain high calorific gas from biomass and wastes. Demonstration tests carried at Ebara's Sodegaura Plant confirmed that the quality of the product gas from this ICFG was sufficient for this gas to be used as alternative fuel for gas engines and gas burners. As the ICFG is capable of gasifying various wastes and biomass, its product gas can be refined and used as gas fuel and liquid fuel by other facilities in the proximity. The versatility of this ICFG model makes it possible to recover energy under various influent waste conditions.

Keywords
Fluidized bed, Gasification, Biomass, Sewage sludge, Waste plastics, Alternative fuel, Gas engine, Reduction of primary energy consumption, Reduction of green house gas emission, Methanol

by Takashi KAWANISHI
Ebara's Kerosene Type Home-use Fuel Cell Co-generation System has been released into the market. This energy-and cost-efficient system, comprising a polymer electrolyte fuel cell unit and a heat recovery hot water storage unit, features a performance which equals to those of city gas and LPG type such systems. The following touches on fuel cell systems and discusses our kerosene type fuel cell co-generation system, specially designed for home use.

Keywords
Kerosene, Fuel cell, Cogeneration, Reformation, Catalyst, System, Re former, Generation, Hot water tank, Polymer electrolyte fuel cell

by Shinji MIURA, Kaoru KIKUCHI, & Syuichi UENO
Ebara's novel and unprecedented ion exchange resin cleaning system, for use in BWR plants and featuring a vibration separator and basic design factors of Radiological Solutions, Inc., had been delivered to Tokai No. 2 Power Station, Japan Atomic Power Company, in October 2005. This compactly-designed system effectively separates crud and resin fines from ion exchange resins, with no clogging of separation screens. It generates minimized waste liquid and has a specially designed over-pack cleaning tank. The system has been in operation for about a year now and favorable operational data and evaluation results are being reported from the owner-side.

Keywords
Condensate demineralizer, Ion exchange resin, Crud, Resin fines, Vibration separator, Back wash, Separation efficiency, Spray, Liquid phase radioactive waste

by Shogo MATSUOKA, Ikuhisa YOKOTA, & Hideaki AOYAMA
Ebara's fly-ash and bottom-ash treatment system, core components comprising a submerged arc furnace (off-gas electric resistance furnace) and a dechlorination process, is contributing to the Zero Emission standard of Chubu Recycling Co., Ltd. This system is enabling treatment and resource recovery of fly-ash and bottom-ash from various incineration facilities, including molten fly-ash with highly concentrated chlorine content which is normally land-filled. Products from melting processes (e.g. sorted ferrous matter, molten metal, slag and molten fly-ash) are being recovered as added-value resources. The total amount of influent bottom-ash and fly-ash at the Chubu Recycling facility between 2004-2006 had been about 64000 tons. Out of this, about 35000 tons of slow cooling slag, about 3700 tons of molten metals, and about 700 tons of zinc resource had been recovered.

Keywords
Bottom ash, Fly ash, Recycle, Submerged electric arc furnace, Dechlorination, Slow cooling slag, Off-gas electric resistance furnace, Zinc, Lead, Copper, Rare metal, Resource depletion

by Kenji YAMASAKI, Kenji SUZUKI, & Takuya NAKANISHI
The construction of Choshi Wind Farm, located in Chiba Prefecture and featuring the use of seven Ebara-Pfleiderer 1500 kW wind turbine generator systems (Model EPW1570), had been completed in February 2007. This project is noteworthy in that it is Ebara-Pfleiderer's first execution of it's Wind Farm Plan which proposes the use of multiple wind turbine generators in a single wind farm.

Keywords
Wind turbine generator system, Wind farm, Global warming, New and renewable energy, Choshi

by Satoshi SEKIZUKA, Hiroshi OKAZAKI, & Sumio SAITO
This is sequel of a previous paper on the results of an on-site study on two wind turbine generator systems, for which two control methods had been used and compared. In this sequel, the results of a comprehensive performance evaluation on transient characteristic for various electric parameters, versus transitions in power output, are discussed.

Keywords
Wind turbine, Wind turbine generator system, Propeller type wind turbine, Power control, Constant speed wind turbine, Variable speed wind turbine, Wind speed, Induction generator, Asynchronous generator, Power curve

by Kunio FUJIWARA
Radiation-induced graft polymerization (RIGP) enables the production of separation functional polymers while retaining the physical characteristic of an existing polymer shape. EBARA's RIGP process, in use for more than 2 decades, has been proven effective for manufacturing ion-exchange, non-woven fabric for filtration in air and water purification. We are also involved in the sales of grafted filtration material. The following introduces the RIGP process, including some examples of application.

Keywords
Radiation induced graft polymerization, Ion exchange, Functional polymer, Non-woven fabric, Chemical filter, Electro-dialysis, Anti-bacterial activities, Electron beam, Polyethylene, Radical

by Yutaka OSHIMA, Taizo IWATANI, & Tatsuo SHIMOMURA
An electrolysis-reduction process for remediation of lead-contaminated soil has been developed. This process can accept lead-contaminated silt slurry discharged from a soil-washing process. It is capable of reducing the contamination level to Japan's national criteria for fill-back at the source. This process is unprecedented for remediation of heavy-metal contaminated soil in that no off-site dumping becomes necessary. An electroplating method was applied for the deposition of lead extracted from contaminated silt. Lead in sparingly soluble forms could be extracted from silt, under low pH and reductive potential in the electrolysis reactor. The deposition of metal-lead on the electrode reduces lead-ion concentration in the liquid phase of the silt slurry and enables efficient extraction of lead from the silt.

Keywords
Electrolysis-reduction process, Contaminated soil, Soil remediation methods, Soil-washing, Lead, Heavy-metal, Plating

by Takeshi UOZUMI, Satoru INOUE, & Hirotaka AKAGAWA
EBARA's rotary kiln and stoker system is being operated favorably at an industrial waste incineration power plant run by GE Co., Ltd, of Sakai City, Osaka. Various wastes are being treated at this plant such as sludge, plastic, paper, fiber, animal and botanical residue, contagious medical wastes, acid and alkaline liquids, and oil sludge. The system's rotary kiln conducts a well-balanced drying and combusting of such wastes which carry different properties and calorific values, while the downstream stoker and the secondary combustion chamber achieve complete combustion. Heat from the flue gas is recovered as steam in the waste heat boiler, this steam used for generating 265 kW of power by a turbine generator. This steam is also used as a heat source for a sludge drier and a flue gas re-heater.

Keywords
Kiln-stoker system, Industrial waste, Hospital waste, Waste oil, Waste liquid, Sludge, Waste heat boiler, Steam turbine, Generator, Catalytic reaction tower

by Masao OSHIMA, & Toru ISHIDO
The ISO/TC113/SC2 meeting was held in London on April 27 and 28, 2006. In this meeting a draft international standard (ISO/DIS 1438-1) on flow measurement in open channels using thin plate weirs was discussed, specifying only the Rehbock formula for determining the flow with full width weirs which are applied widely for measuring the discharge flow of large size pumps. Other formulae, including the JIS formula, specified in a previous edition were not considered. The Rehbock formula shows much deviation when used for weir plates higher than 1 m. The authors proposed at the said meeting an amendment in Rehbock formula, for application in the range of weir plate height of over 1 m, referring to the effect of the weir plate boundary layer on the flow coefficient. This paper reports how the meeting proceeded, along with some background regarding the authors' proposal.

Keywords
ISO, Weir, ISO 1438-1, JIS B 8302, Flow measurement, Thin plate weir, JIS formula, Rehbock formula, Flow coefficient, Boundary layer

by Hiroshi KOZUKA, Yasuko ETO, Haruo OKAZAKI, Aiko YOKOSUKA, & Yukiyoshi HATORI
LCA (Life Cycle Assessment) is a method of assessing the life cycle of a product to grasp its environmental impact, from its manufacturing, usage and all the way to its disposal. An LCA database, featuring environmental impact unit data of the supply chain compiled from environmental and production management data from EBARA's Haneda Plant and associate companies, has been created. An LCA system which uses this database for calculating the environmental impact of each product from its specifications has been developed. This system enables easy calculation of environmental impact by custom ordered, large-sized pumps, thus making it possible for us to contribute to environmental protection by offering eco-friendly products. The promotion and implementation of activities for minimizing environmental impact can be done efficiently as the system is capable to reveal problems in each manufacturing process.

Keywords
LCA of product, Database by basic unit, Eco-friendly products, Activities for reducing environmental impact, Supply chain, Global warming potential, Photochemical ozone creation potential, Recycling

by Kazuaki SHIMAMURA, Asei MIZUOKA, Takao HAGINO, Hideyuki ISHIKAWA, Yuichi FUCHU, & Izumi HIRASAWA
The authors have developed a novel phosphorus recovery process for recovery of MAP (Magnesium Ammonium Phosphate), as well as for separation-recovery of crystallized phosphorus from digested sludge in water treatment plants. The process was developed in an effort to reduce the phosphorus load and increase the MAP recovery amount in water treatment systems. The main components of this process are a complete-mixing type crystallization reactor and a hydro-cyclone. The crystallization phenomenon of phosphorus in digested sludge was studied through a preliminary experiment and conditions for suppressing the generation of micro-crystal MAP determined. A demonstration test using anaerobically digested sludge was carried out using a pilot test system (treatment capacity: 6 m3/day) which was installed in a wastewater treatment plant. Stable MAP recovery, constituting over 30% of T-P in the digested sludge, was achieved through the 6 month duration of the demonstration test, thus demonstrating the practicality of this process.

Keywords
Phosphorus recovery, Crystallization, Magnesium Ammonium Phosphate, Anaerobically digested sludge, Hydrocyclone, Complete mixing, Scale, Eutrophication, Sewage

by Keiichi KURASHINA, Tsutomu NAKADA, & Manabu TSUJIMURA
A novel Cu planer plating technique which enables CMP cost reduction has been proposed and investigated. A finding was made that pressing a porous pad with through-holes against the wafer surface while plating results in the suppression of Cu growth on the field area, as well as a growth of Cu posts only in the through-holes. These Cu posts could be easily and selectively removed by chemical etching, and thus enabling planer Cu plating films with less overburden than that of conventional plating methods. Cu CMP of these films took less time and better step height reduction property could be attained.

Keywords
Plating, Etching, CMP, Semiconductor, Wafer, Copper, Planarity, Overburden, Pad, Porous material

by Ryota MIKI, & Masahito KAWAI
A new type pump for use in shallow wells was developed. Some features of this pump are an integrated piping base, a coupling pipe installed at the lower part of the base for communicating three discharge outlets. This design has made it possible to select the direction of discharge from among three outlets. A flow check device, which includes both a flow switch and a check valve, has allowed a reduction in the number of parts, thus making the pump more compact and lightweight (20% reduction in installation space) than conventional models. The exchange of mechanical seals can be done easily by simply sliding the motor backward after loosening the nuts securing it, thus making it unnecessary to remove the pump casing from the unit base for such exchange.

Keywords
Flexibility of installation, Miniaturize, Lightweight, Plural discharge, Maintenance, Flow check, Parts reduction, Shallow wells, stable supply with water, Small scale institution

by Yuzo NARASAKI, Kazuya KONISHI, & Shigeru KOMEKYU
A compact VOC (Volatile Organic Compound) bio-treatment system, requiring no external energy resource and causing minimized impact on the environment, was developed and released into the market. This system, featuring a foreign-made VOC biofilter system, was developed targeting small-to-medium businesses in the printing and paint industries, who need to reduce VOC emission by the year 2010, in compliance to an amendment made in Japan's air pollution prevention law. The usability of this system was confirmed through a one-year pilot test at an actual plant.

Keywords
VOC (Volatile Organic Compounds), Printing•Painting, Biological treatment, VOC concentration, Removal efficiency, Flow rate, Pilot equipment, Field test

by Yoshio MOGI, Toshiyuki OGAWA, & Takafumi KOGUCHI
EBARA's Cryogenic Pump Test Center, located in the Sodegaura Plant, is a facility for testing the performance of EBARA's cryogenic submerged motor pump. The facility is capable of tests using LNG (Liquefied Natural Gas) and LPG (Liquefied Petroleum Gas). This facility's capacity includes a maximum flow rate of 3000 m3/h, a maximum pressure of 10 MPa, and a maximum motor power of 2000 kW. Its data acquisition specifications comply with ISO 9906 (Rotodynamic pumps - Hydraulic performance acceptance tests-Grades 1 and 2) and other than performance tests, functional tests such as NPSH tests and vibration measurement tests and can be carried out simultaneously. Labor-saving facility management, such as by remote monitoring and automatic control, and reduction in testing time, by automatic measurement, are featured as well.

Keywords
Cryogenic pump, Test center, Liquified Natural Gas (LNG), Liquified Petroleum Gas (LPG), Performance test, NPSH test, Automatic measurement, Central control, Automatic control, Sodegaura plant

by Hiroshi YAMAGUCHI
EBARA has completed the reconstruction of the large-scale pump facility at Inba Drainage Pump Station (capacity: 92 m3/s) in Northern Chiba Prefecture. The reconstruction, featuring multiple unprecedented totalized engineering techniques, was conducted between March 2003 to July 2006. A total of 6 new pumps, two each year, were installed. Unlike the construction of a new such pump facility, the work was done in a totalized manner, involving civil, structural, mechanical and electrical engineering techniques. This approach enabled a considerable saving in construction time and costs. Notable is that several actual drainage operations were able to be conducted during the course of the construction, thus contributing to the regional community.

Keywords
Drainage pump station, Restore functions, Renovation, Vertical axial flow pump, High efficiency, Short construction schedule, Concrete cutter with low vibration, Wire saw, Short length multiple guide vanes, Lightweight

by Eiko TOMINAGA, Takeo OHKOUCHI, & Yoshiaki MIYAZAKI
The DML model submersible pump, whose performance has been proven overseas and which features highly efficient passage of foreign substances, is being installed in manhole pump units in Japan. This pump enables a saving in running costs of manhole pump units, namely in terms of power consumption and maintenance. The following introduces experimental and on-site tests conducted prior to commissioning.

Keywords
Manhole pump unit, Pump efficiency, Foreign substance passage test, Impeller passage, Electricity fee, Vortex type, Non-clog type

by Masashi OHBUCHI, & Masashi TAGOMORI
A finding was made that the water-levels of each of two mirror-symmetrical, coupled pits of a pump sump fluctuated alternatively. This phenomenon, attributed to a fluctuation in flow pattern at the expanding duct situated upstream the sump pits, was able to be predicted by CFD (Computational Fluid Dynamics) analysis. The following discusses this and includes an outline on the mechanism of submerged and air-entrained vortices in the pits, as well as on a practical countermeasure against these unfavorable vortices.

Keywords
Pump sump, Flow analysis, Vortex, Water-level fluctuation, Sump diagnosis, Countermeasures against vortices