VOL.25 NO.2 (published in Dec-2017)

Photo in Cover :Suwakoshu Clean Center

VOL.25 NO.2 (published in Dec-2017)

The Trend of Power Generation using Wooden Biomass in the Feed- in Tariff System for Renewable Energy

Yoshiyuki MIYAJIMA*
(*Plant Sales Dept. II)

(Abstract)

It has been six years since the start of the feed-in tariff system (FIT system) of renewable energies. Many wooden biomass power plants have been constructed during this period. As of the end of fiscal year 2016, 32 biomass power plants with the capacity of 2 MW or more are generating approximately 290,000 kW of power using unused lumbers. In addition, 20 biomass power plants are generating 330,000 kW using wooden materials and agricultural residues. Starting in FY2015, the new category of biomass power generation using unused lumber was added, which sells less than 2 MW for 40 yen/kWh. The enforcement of the revised FIT law in FY2017 caused a drastic change in the system. Meanwhile, there was a trend of reducing biomass power generation using wooden materials in general and agricultural residues with the capacity of 20 MW or more if they are using imported lumbers or PKS. The sales price of the power generated from such fuel was reduced from 24 yen/kWh to 21 yen/kWh starting in October 2017. Given these changes, the spread of biomass power generation using wooden materials in general and agricultural residue will slow down and gradually shift to biomass power generation using unused lumbers.

Suwakoshu Clean Center Operation Report

Hideyuki NISHIZAWA*
(*Environmental Engineering Dept. I)

(Abstract)

Suwakoshu Clean Center was constructed in November 2016. This facility is designed to process wastes from large areas by integrating waste treatment facilities which are originally located in two cities and one town including Okaya city, Suwa city, and Shimosuwa town located in the periphery of the Suwako Lake, Nagano. For this facility, the operation is proposed to be higher than the high-efficiency waste power generation eligibility requirement (14.0% of power generation efficiency). Also, the voluntary control value that is higher than a required level is set for the facility, which has been operating with the high standard. This paper examines the achievement status of the business proposal and reports the conditions of the high-efficiency waste power generation which is the special characteristic of this facility.

The Technology to Reinforce the Processing Capacity of Already OperatingWater Treatment Facility using Carrier Method and High- speed Sand Filtration

Masanobu FUKUZAWA*, Tomoyuki DOI*, Kenichi SHISHIDA*
(*Sewerage Engineering Dept.)

(Abstract)

Sewage treatment facilities are starting to add treatment facilities to use advanced treatment systems to remove nitrogen and phosphorus and reform and renewal of foundation and structure to repair age-based deterioration. Challenges for sewage treatment facilities include the acquisition of necessary land and the reduction of construction cost. We developed technologies to add treatment capacity to already operating water treatment facilities using carrier method and high-speed sand filtration which enable low-cost advanced treatment and renewal in plants with limited land availability with Japan Sewage Works Agency, and JFE Engineering. This paper reports the outcomes of experimental tests conducted in combination with actual facilities and pilot plant in addition to case studies including estimated life cycle cost. In the experimental test, the quality of treated water achieved the target quality throughout the year, which demonstrated the capability of stable operation. This test demonstrated that this technology was capable of reinforcing the treatment capacity of an already operating advanced treatment facility by up to about two times. In the case study, the life cycle cost of renewing a facility with this technology was estimated to be approximately 32% lower than conventional technologies.

The Effectiveness of using Two- agent Conditioning Type Screw- press Dehydration Sludge in Incinerating Power Generation System with Advanced Step Grate Stoker Furnace

Hiroki MURAGISHI*, Yukiya ATSUMI*, Taro KURUSU*, Takaaki MIZUNO*, Satoshi HAGITA*
(*Sewerage Engineering Dept.)

(Abstract)

“Technical demonstration and study on power generation system from sewage biomass sourse” was conducted in FY2013 and FY2014 as a B-DASH Project of Ministry of Land, Infrastructure, Transport and Tourism. This system used an inside two-agent conditioning type centrifugal dehydrator, and the incinerating power generation was tested in an advanced step grate stoker furnace. Meanwhile, in screw-press dehydrator which the power consumption is about one-third of centrifugal dehydrator, two-agent conditioning type has been developed as commercial products. This type of dehydrator has started to be introduced in sewage treatment plants. This study tested the incineration of sludge dehydrated with screw-press in an experimental furnace with advanced step grate stoker furnace. We confirmed that the ignition loss of incineration ash and the concentration of emitted CO were easily satisfied target values. The study therefore confirmed that the sludge dehydrated with screw-press could be effectively used in advanced step grate stoker furnace just like the sludge dehydrated with centrifugal dehydrator. In addition, we calculated and confirmed that this system can increase excess power supply to outside and reduce operating cost of whole facility by reducing power consumption of dehydrator.

Full- scale Demonstration on High- efficiency Nitrogen Removal Technology by Fixed- bed Type Anammox Process ;Part 6 -Experimental Examination Concerning Mid- to- Long Term Suspension-

Keita TAKAKI*, Tomoyuki DOI*, Kenichi SHISHIDA*
(*Sewerage Engineering Dept.)

(Abstract)

Using a full-scale fixed-bed type anammox process demonstration plant constructed at Tobu wastewater treatment plant at Kumamoto City, further cost reduction and stabilization treatment of this process is being considered after the completion of B-DASH (2012-2013). This report describes effects related to mid-to-long-term suspension and restart of this anammox plant. The plant was suspended for up to 17 days during holidays in summer and winter and then started a restart test. The test confirmed that it was capable of immediately restart at the same level of processing capacity as before the suspension. In addition, also the plant was suspended for approximately one month after the 2016 Kumamoto Earthquake and during maintenance of major equipment, microorganisms in both the nitritation tank and the anammox tank maintained their activities, and the plant was restarted in a short period of time.

Back to Technical Review

Page Top