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Ebara Engineering Review No.204

Experiment and CFD of Cavitation in a Centrifugal Pump

by Motohiko NOHMI, Akira GOTO, Tatsuyoshi KATSUMATA, Yuka IGA, & Toshiaki IKOHAGI

The cavitation flow in a low specific speed centrifugal pump was measured in detail. Pressure transducers were installed in impeller vanes and unsteady pressure distribution over the pressure and suction sides was studied. Cavitation characteristics were photographed along the axial direction in the inlet volute casing and front shroud. Cavitation flow in the pump was numerically analyzed using a locally homogeneous cavitation model of a compressible air-vapor-liquid, two-phase medium. Under a BEP (Best Efficiency Point) flow rate, bubble cavitation increased along the suction side when decreasing the NPSH. When this bubble cavitation reached the throat, a wedge-like cavity appeared at the pressure side and a steep head breakdown occurred. This breakdown was found to be reasonably predictable by using cavitation CFD.

Centrifugal pump, Cavitation breakdown, Pressure measurement, Cavitation CFD, Cavitation modeling

High-load treatment by Moving-bed Biofilm Process using Sponge Media

by Mitsuhiro TOKUNO, Hiroshi SAKUMA, Yuichi FUCHU, & Akihiro IKEDA

Tests were done at a paper mill to study the performance of a moving-bed biofilm process, featuring the use of sponge media (Type Ⅱ Ebafoam), for treating wastewater. An S-COD removal exceeding 65% was indicated under a COD volumetric load of below 4 kg/(m3·day), and a high S-BOD removal of 90% under a BOD volumetric load of below 3.5 kg/(m3·sssday). Based on such findings, a sponge-media-using, moving-bed biofilm treatment system was employed at the paper mill. This system is achieving an S-COD removal of 60%, the designed value, under the design S-COD volumetric load of below 2.5 kg/(m3·day). The use of this system for treating other industrial wastewater and at small-scale sewage treatment plants is being looked into.

Sponge media, Moving bed, Biofilm process, Volumetric loading, Activated sludge process, Paper mill wastewater, Sewage, Industrial wastewater, Chemical clarification, Aluminum sulfate

Cogeneration through the processing of Domestic Kitchen Waste and Night Soil Sludge in a Full-scale Sludge Treatment Plant

by Yutaka YONEYAMA, Katsuhiro TAKENO, Kikuo SHIMIZU, Tatsuo NAITO, Fumio ITAGAKI, Yoshimitsu YASUHARA, & Mutsuo NAKADA

A sludge recycling and treatment center that makes use of thermophilic methane fermentation from domestic kitchen waste and night soil sludge started operation in Japan in 2000. The characteristics of the raw material (night soil sludge, domestic kitchen waste), the performance of methane fermentation, the effect of recycle flow on the water treatment system and the cogeneration of electric power has been studied by collecting methane fermentation data for two years. During this periods, stable methane fermentation performance was achieved. The highest electrical power generation by methane gas was 2,243 kWh/day. This was equivalent to about 15.3% of the power consumed at the entire sludge treatment plant. Due to the return water flow from the methane fermentation process, the BOD/Kj-N of the activated sludge influent water was lower compared to when there is no recycle flow. Therefore, there was a tendency for the amount of methanol charged into the secondary denitrificatin tank to increase. However, the cost of this consumed methanol was small compared to the total running costs. Results indicate that is possible to implement a full-scale treatment plant that makes practical use of organic waste.

Methane fermentation, Full-scale process, Night soil, Septic tank sludge, Household kitchen waste

Microbial Structure Analysis of Contaminated Soils utilizing Molecular Biological Tools

by Akiko MIYA, Makiko KARUBE, & Kazuaki SYUTSUBO

A study was made on the biodegradation of petroleum-contaminated soils using weathered crude oil and phenanthrene as hydrocarbon sources. Experiments were conducted to study oil biodegradation characteristics of soil samples and analyses were made on microbial structures by PCR-DGGE in an attempt to identify dominant petroleum biodegrading bacteria. Study results indicated that the combination of an appropriate propagation method and a microbial analysis could enable estimating biostimulation effects of petroleum-contaminated soils within a relatively short time.

Contaminated soil, Bioremediation, Molecular biological tools, Microbial structure, PCR, DGGE, Isolation, Petoleum hydrocarbon-contaminated soils, Alkanes

Development of a Total Management System for supporting BPR in Environmental Engineering Business

by Teruaki KITAMURA, Yuji WADA, Koichi HAYAKAWA, & Kazuhiro ESAKI

A new total management system, named the e-Human's, has been developed for supporting BPR (Business Process Re-engineering) in environmental engineering business. This system makes use of leading edge IT to enable re-engineering of business processes for large-scale projects, optimization of project management, application of foreign standards, minimization of construction costs, as well as enhancement of proposals.

BPR (Business Process Re-Engineering), IT (Information Technology), O & M (Operation & Maintenance), Environmental Engineering Business, PMS (Project Management System), EDMS (Engineering Document Management System), MMS (Material Management System), Web-EDI

Innovations in IT-infrastructure using Total Information Management System for Environmental Engineering Business

by Tetsuro OKOCHI, Shoji MIZUTANI, Seiichi TSUJI, & Kazuhiro ESAKI

EBARA's e-Human's is a total information management system which supports large-scale innovations, such as for document management, project management and external procurement functions, in the IT-infrastructure for environmental engineering business. A shift from mainframe to open server systems is now taking place in this field of business. In 2002, the total number of servers within EBARA for subsystems reached 170, including 5 host systems. This posed serious security and management risk, not to mention high management costs and difficulties in the management of open systems. Progress in IT is making it imperative to achieve co-ownership and active use of information among different EBARA entities and clients, while maintaining adequate security. These factors are becoming indispensable for boosting corporate competitiveness. The following discusses the application of e-Human's to environment engineering business and innovations made in EBARA's IT-infrastructure while solving abovementioned problems.

IT : Information Technology, IT-Infrastructure, Mainframe, TCO: Total Cost of Ownership, Identity Management, EIP: Enterprise Information Portal, Database, Server, System, EAI: Enterprise Application Integration

Web-utilizing Monitoring System for Manhole Pumps

by Eiko TOMINAGA, Kenichi FUJITA, Masanori SAITO, & Takahiro ISOZAKI

The EMMD-Web unit is an IT device for monitoring manhole pump facilities via computer Internet browsers. The following introduces a manhole pump monitoring system which features this EMMD-Web unit. This system enables efficient and thorough monitoring.

Manhole pump, Monitoring system, Monitoring device, Low cost, Maintenance, EMMD-Web Unit, Modem, Terminal adaptor, Provider, Radio monitoring system

A Fuel Feed Pump for Jet Engines

by Takahisa SEKINO, & Hirofumi NAKAYAMA

A fuel feed pump has been developed for the engine test cell of ANA (All Nippon Airway) at Haneda International Airport. Jet engines are taken apart and inspected periodically to ensure safety. The last process involves test runs of the reassembled jet engines. The developed fuel feed pump optimally feeds the fuel to the jet engine during such test runs, matching the engine type and controlling the flow rate and pressure for particular load conditions. The following outlines this pump and discusses its features, components and control method.

Fuel feed pump unit, Jet engine, Pressure control valve, Surge tank, Filter separater, Self priming tank, Ejector, Fuel feed pump, Trial run

Tubular Turbine System at Shin-Tawara-Iseki Power Station

by Takeshi ASANO, Shinya HIBINO, & Toshihiro HOSOI

EBARA's tubular turbine (2400 kW) system is being used at Shin-Tawara-Iseki Power Station, located in the Yoshii River Dam in Okayama Prefecture. The new technology featured in this system is a roller-screw-driven runner vane and an electrically-operated runner vane servomotor. The turbine itself is an electrically-operated bulb-type, the first of its kind developed by EBARA. The following outlines this system used in the power station.

Small capacity hydraulic turbine, Tubular turbine, Bulb-type turbine, Electrically-operated runner vane servomotor, All electrically-operated bulb-type turbine