Technologies

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Ebara Engineering Review No.248

Performance of Anaerobic Ammonium Oxidation Process Using Fluidized Carrier Method

by Yongsheng GE, Ryosuke HATA, Hiroshi SAKUMA, Shinji GONO, Hisami NAKAMURA, & Akira YAMAGUCHI

This study examined a nitrogen removal process based on an anammox (anaerobic ammonium oxidation) process that enables lower energy consumption and processing at lower costs than the conventional method. On the basis of the findings of a basic study of the partial nitritation process and the anammox process using synthetic wastewater, demonstration tests using actual wastewater were conducted. First, a demonstration test was conducted with fluid with digested sludge filtrate that had been separated from sewage and that was characterized by a low concentration of organic substances and a high nitrogen concentration. It was followed by another demonstration test using leachate with a low amount of suspended solids (SS) and organic substance concentrations and a high level of salinity. Both tests lasted about six months or longer. These tests confirmed that both the partial nitritation process with added carriers and the anammox process enabled bacterial attachment and retention of carriers and exhibited stable processing performance. Yet another demonstration test using this fluidized carrier method integrating the partial nitritation process with the anammox process observed a T-N load of 2.4 kg/(m3·d) at maximum with digested sludge filtrate and 2.7 kg/(m3·d) at maximum with the leachate. It also confirmed good nitrogen removal performance with a T-N removal rate of 80% or higher on average in both cases.

Keywords
Nitrogen removal, Nitritation treatment, Anaerobic ammonium oxidation (Anammox), Ammonium, Fluidized carrier method, Free ammonium, Free nitrous acid, Digested sludge, Dewatered filtrate, Leachate

Fluidized-bed Incineration Plant for Multiple Industrial Waste and Sludge

by Hiroyuki SUZUKI, Nobuyuki OTABE, Tetsuji MARUYAMA, & Yoko SATO

Ebara Environmental Plant Co., Ltd. recently finished the construction of an industrial waste incineration system for Clean Power Yamagata Co., Ltd. and delivered a fluidized-bed waste incineration system. Incorporating the twin interchanging fluidized-bed (TIF)incinerator, this system takes advantage of the mixing and crushing effect of fluidized-bed to treat mixture of various waste including sludge, waste oil, liquid waste, waste plastics etc., with compliance to severe emission standard and with high-efficiency power generation.

Keywords
Industrial waste, Sludge, Fluidized-bed, Incinerator, Combined waste incineration, Monitoring and operational control equipment, Distributed control system (DCS)

Waste Incineration Facility with Urban Disaster Prevention Center Functions in Musashino City

by Teruaki TSUKAMOTO

Waste incineration facilities are recently required to be more stanch to serve as disaster prevention facilities in addition to providing value-added functions, such as effective energy utilization and contribution to local communities. The Musashino Clean Center has attracted attention as an urban facility adjacent to a municipal government building. Its design-build-operate (DBO) project, including 20 years of operation, was tendered for under the comprehensive evaluation system in 2013. Ebara Environmental plant Co., Ltd. submitted a proposal reinforcing the concept sought by the municipal government by making the most of the latest technologies and 29 years of operational experience. This paper reviews the facility’s enhancements in quake resistance, construction of a cogeneration system that coveres neighboring facilities in preparation for emergency and support to temporary evacuees, facility design ensuring early resumption of independent operations and the creation of safe and secured facilities on the basis of the experiences of the Great East Japan Earthquake.

Keywords
Waste incineration, Disaster-prevention facility, Toughening, Energy, Seismic design, Cogeneration system, High efficiency power generation from waste

Basic Knowledge about Pump Cavitation Phenomenon [Part 3]

by Motohiko NOHMI

This paper explains erosion problems caused by pump cavitation. A single spherical bubble with low pressure shrinks rapidly if it flows into a high pressure area; when the bubble finally collapses, it generates a high pressure wave propagating to ambient solids. If the bubble is close to the ambient solid surface and deforms into a non-spherical shape, a micro jet directed toward the solid surface is generated and impinges against the surface. In a situation where a number of bubbles collapse repeatedly, multiple loads are applied onto the solid surface, resulting in erosion. In order to evaluate the erosion resistance characteristics of materials, two standards, ASTM G32 and ASTM G134, have been established as cavitation erosion tests on materials. Pump erosion can be reduced by using excellent erosion-resistant materials or by applying partial build up welding. Development of erosion prediction by numerical analysis is expected in the future.

Keywords
Cavitation, Cavitation erosion, Bubble collapse, Micro jet, ASTM G32, ASTM G134, Built up welding

Water Supply Equipment: Introduction of Product Technologies
− Part 4: Variable Frequency Control System −

by Kazuhiro KANEDA

We provided explanation on the topics of various water supply systems, their purposes and how to select them, in the first and second series of technical introduction of the water supply equipment (water supply units) which are our company’s main products. In the third series, we explained the “ON-OFF control system”, the most basic system of controlling pressure among water supply systems. In this fourth part of the series we will cover the “variable frequency control system”, which is superior to the “ON-OFF control system” in suppressing water pressure fluctuations and can operate with a high degree of energy saving, and the water supply equipment that utilizes the system. The introduction will include topics such as details of the control system, actual structure and main components, various special specifications, and protective functions for its safe operation.

Keywords
Water supply equipment, Water supply system, Variable frequency control system, Inverter, Energy saving, Estimated constant end-pressure control, Control system backup, Pressure sensor, Special specifications, Protective function