Technologies

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Ebara Engineering Review No.249

Technologies Used for the High-efficiency Waste Power Generation Plant with Advanced Fluidized-bed Incinerators
- Operating Status of the Hiratsuka-city “Kankyoujigyou Center” (Environment Management Center) -

by Arihiro OKAMOTO

The Hiratsuka-city Kankyoujigyou Center (Environment management center) is a facility that was built based on a “design, build, and operate” (DBO) scheme. This facility, whose period of operation is 20 years, has been operating steadily for the approximately 1.5 years since its completion and delivery in September 2013. It is equipped with fluidized-bed incinerators with a treatment capacity of 315 tons/day (105 tons/24 hours × 3 units). Taking advantage of the features of the fluidized-bed incinerators, the facility keeps the fluctuations in transmitted power small while treating waste stably, thereby maximizing its functions as a green power plant.
This paper reports the operation conditions of the facility over the 1.5 years since its completion and the measures which are adopped to the generated/transmitted power control.

Keywords
Fluidized-bed, Waste, Incinerator, Waste to Energy (WtE), Gross/Net thermal efficiency, Control of generated power, Control of transmitted power

Technology for Phosphorus Removal and Recovery from Digested Sewage Sludge

by Daisuke KOGA, & Takao HAGINO

Japan’s demand for phosphorus is met entirely by imports. It is an extremely valuable resource that is indispensable to fertilizers and industrial applications. On the other hand, sewage treatment plants face issues such as reducing the phosphorus load in discharged water and the level of scaling caused by phosphorus. To address these issues, the mechanical agitation-type magnesium ammonium phosphate (MAP) method was developed. This method makes it possible to recover the phosphorus in digestive sludge in the form of MAP. The joint agri-service research consortium of Swing Corporation, the Kobe City Government, and Mitsubishi Corporation was commissioned by the Ministry of Land, Infrastructure, Transport and Tourism to conduct a demonstration of the technology at a real-scale demonstration plant as part of a “Breakthrough by Dynamic Approach in Sewage High Technology Project (B-DASH Project).” The demonstration confirmed that the method reliably delivers the desired level of performance, and it is estimated to recover around 1.8 times the MAP of conventional methods. Because MAP has already been registered as a fertilizer, Swing is conducting a joint study with Kobe City Government on practical applications in the Kobe area.

Keywords
Phosphorus, MAP (struvite), Crystallization, Anaerobic digested sludge, Fertilizer

Stoker-Type Waste Incineration Plant for Iwamizawa, Hokkaido
Construction and Delivery of Iwamizawa Environment Clean Plaza

by Naoto AKIBA, & Tetsuji IGUCHI

We delivered the Iwamizawa Environment Clean Plaza, a waste incineration facility with a stoker-type furnace, to Iwamizawa City, Hokkaido at the end of March 2015. This facility is designed to treat the waste collected from three municipalities: Iwamizawa City, Bibai City, and Tsukigata-cho. The Iwamizawa Environment Clean Plaza is a comprehensive waste treatment facility that consists of a stoker-type incineration plant and a recycling plant. This cutting edge facility creates a low environmental impact thanks to state-of-the-art stoker technology. It also provides for the advanced treatment of flue gas, and works to effectively utilize energy by generating electricity from waste heat at incineration. The facility gives full consideration to the harmony with both of the natural and social environments, while seeking to provide the economic benefits to the municipalities it serves. We employed various measures, including introduction of pre-fabricated stokers, to cope with the very short delivery time from the contract to the completion of construction. The performance test confirmed that the facility achieved the designed performances.

Keywords
Stoker type incinerator, Incineration plant, Recycling plant, State-of-the-art stoker technology, Low air ratio combustion, Flue gas recirculation, Generating power from waste, Prefabricated stoker, Pin-bound type grate, Closed wastewater treatment system

Renewal of Shinkawa-kako Drainage Pump Station (Second Report)

by Yoshio KUDO, Hideyasu TAKEDA, Hiroyuki OSAWA, & Makoto KOMIYA

The Shinkawa-kako drainage pump station, which is one of the nation’s largest drainage pump stations, built in Nishikanbara district, Niigata city, has just undergone renewal construction of the pump facilities. In the construction, the tubular type horizontal axial flow pumps of bore 4200 mm with a concrete casing structure were removed and replaced, with the existing building frame reused. This was challenging work because all the six pumps had to be replaced in turns, one pump in the dry season each year, while the draining function of the pump station was being maintained. Although a variety of issues arose at the time, the renewal construction was steadily carried out to be completed based on know-how obtained from similar work conducted by EBARA.
The first report described the features of this drainage pump station and the design considerations of the renewal construction. Therefore this second report introduces viewpoints and innovative ideas of renewal construction on the site.

Keywords
Concrete casing, Renewal construction, Wire sawing, Tubular type horizontal axial flow pump, Adjustable vanes, Reuse, Underground structure, Drainage pump station, Dry season

Water Supply Equipment: Introduction of Product Technologies
− Part 5: Direct Connecting Booster Pump −

by Nobuhiro HIGAKI

We discussed 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 unit) which comprises our company’s main products. Subsequently, we explained the “ON-OFF control system”, the most basic pressure control system among water supply systems, and the “variable frequency control system” which is superior to the “ON-OFF control system” in suppressing water pressure fluctuations and which can operate with a high degree of energy saving, in the third and fourth parts of the series respectively.
In this fifth part of the series, we will introduce the “direct connecting booster pump system”, which is a system that increases only necessary water supply pressure in a way that makes up for insufficient pressure of the main pipe while taking advantage of its pressure with water supply equipment directly connected to a pipe branched from the main pipe, and also explain about the water supply equipment that utilizes the system. We will include details of the control system, its actual structure and main components, various special specifications, and protective functions for its safe operation.

Keywords
Water supply equipment, Water supply system, Direct connecting booster pump system, Variable frequency control system, Back flow preventer, Estimated constant end pressure control, Flow switch, Pressure sensor, Direct connecting booster pump system (serially cascaded type)