Research Trends and Results
Empirical Studies for The B-DASH Project (Solid fuel forming,sewage heat utilization, nitrogen removal, phosphorus removal /recovery)
YAMASHITA Hiromasa , Head; TAJIMA Atsushi , Senior Researcher; FUJII Tsuyako , Researcher;
HAMADA Tomoyuki , Researcher; MICHINAKA Atsuko (Dr. Env.), Researcher; ONISHI Shohei ,Researcher; KAWASUMI Ryota , Researcher; OGOSHI Masashi (D.Eng.), Researcher; KAMATANI
Satoshi , Guest Research Engineer
Wastewater and Sludge Management Division, Water Quality Control Department
MATSUHASHI Manabu , Researcher
Wastewater System Division, Water Quality Control Department
Keywords: sewerage, energy-saving, resource-saving, cost reduction, greenhouse gas, innovative technology
1. Introduction
Sewerage infrastructure is social capital essential to
public life and its potential uses, e.g., utilization of
sewage sludge and sewage heat as energy, and utilizationof phosphorus as resource are increasingly sought as a
response to the issues of global warming and the tightsupply of resources and energy, as well as measures for
reducing greenhouse gases.
New technologies responding to such social andadministration needs have begun to be developed but areless used in practice since many sewerage service
providers are cautious about their introduction. For thisreason, the Sewerage and Sewage Purification
Department of the MLIT launched the "Breakthrough by
Dynamic Approach in Sewage High Technology"(B-DASH) project in fiscal 2011, and the Water Quality
Control Department of the NILIM serves as an executing
agency of this empirical study. The objective of theB-DASH project is to reduce the costs of sewerage
projects, create renewable energy through the verificationand dissemination of innovative technologies and support
the overseas development of the water business byJapanese enterprises.
2. Outline of the B-DASH Project
Under the B-DASH Project, the NILIM contracts out
studies of innovative technologies to the public andconducts peer reviews of research organizations(contractor) that build full-scale sewage treatment plants
in order to verify treatment stability, the applicability oftechnology, and the cost reductions, decreases ingreenhouse gas emissions, and energy-saving effects
resulting from introduction of the technology, etc.
Based on the results of such verifications, the NILIM
formulates guidelines for introducing the technologies. In
formulating research findings and guidelines, the advice
and evaluations of experts are obtained.
In fiscal 2011, two empirical studies of biogas utilization
technology were conducted and the corresponding
guidelines were formulated in July 2013.
In fiscal 2012, five empirical studies concerningtechnology for converting sewage sludge into solid fuel,technology for utilizing unprocessed sewage heat, andtechnology for removing and recovering nitrogen andphosphorus derived from sludge treatment were adopted.
In fiscal 2013, these studies were continued to verify
results and formulate guidelines.
In fiscal 2013, two empirical studies concerning power
generation system technology using exhaust heat fromcombustion of sewage sludge were adopted, and thetechnology was put into practice.
Of these technologies, this paper gives an overview of theverification technologies adopted in fiscal 2012.
3. Outline of verification technologies adopted
in fiscal 2012
(1) Technology for converting sewage sludge
into solid fuel(i) Empirical study on next-generation
technology for converting sewage sludge into
solid fuel without emitting greenhouse gas(Joint Research Organization of Nagasaki City,
Nagasaki Institute of Applied Science, andMitsubishi Nagasaki Machinery MFG Co., Ltd.)This technology consists of the steps of hydrothermal
reaction, high-rate digestion, dehydration, and drying
processes. The plant hydrolyzes the degradable solidorganic matter in sewage sludge by hydrothermal
reaction, converts water-soluble organic matter into
digester gas through high-rate digestion to utilize it as aheat energy source, and dehydrates and dries the residue
in the remaining sludge to form solid fuel (Photo 1).

Figure 1: Appearance of Verification Facility(Nagasaki Eastern Sewage Treatment Facility)

Agency, and Takuma Co., Ltd.)For removing nitrogen in the returned water derived
from sludge treatment, this technology applies Anammox
reaction technology and a fixed bed (function ofAnammox bacteria converts ammonia and nitrite nitrogen
into nitrogen gas under an anaerobic conditions) to
reduce air demand, chemical costs, sludge generation, etc.
(Figure 4).

(ii) Empirical study on the utilization of waste
heat using low-cost technology for converting
sewage sludge into solid fuel (JFE Engineering
Corp.)The technology uses the unutilized waste heat of anincinerator (about 300 °C) and surplus digester gas as aheat source for drying sludge in order to manufacturesolid fuel with surface solidification drying equipment,
and uses the solid fuel for the incinerator to reduce theuse of supplemental fuel (Figure 2).
Sludge incinerator

Surface solidification dryingequipment

Digester gas

Input dehydrated
cakeWaste heat

Figure 4: Appearance of Verification Facility(Kumamotoshi Eastern Purification Center)

Supplemental fuel (Heavy oil A)- Reduce supplemental fuel (low cost)- Reduce environmental impact (CO2emissions)(ii) Empirical study on innovative technology for
nutrient removal and resource recycling (Jointresearch organization of Swing Corporation,
Kobe City, and Mitsubishi Shoji Agri-ServiceCorporation)
This technology aims to improve phosphorus yield as
MAP (magnesium phosphate ammonium) suitable for
fertilizer raw material by removing and recovering
phosphorus directly from digestive fluid with a complete
mixing crystallization reactor, and to control piping
blockade with MAP (Figure 5).

Sludge solidified fuelBlend RDF fuelFigure 2: Processing Flow (Surface
solidification drying technology)(2) Technology for utilizing unprocessed
sewage heat
○ Empirical study on sewage heat utilization
using in-line heat-recovery technology (Jointresearch organization of Osaka City, Sekisui
Chemical Co., Ltd., and Toa Grout Kogyo Co.,
Ltd.)
This technology installs a heat exchanger in a sewage
pipeline when renovating deteriorated pipe, such as
incurrent pipes and sewage mains at treatment facilities.
Untreated sewage flows through the heat exchanger, andrecovers sewage heat to utilize it for local air conditioning
via a heat pump. The technology enhances theefficiency of the heat pump by utilizing the sewage
temperature, which is higher than outside in winter andlower in summer (Figure 3).

PH adjuster

Separation unit

Flow in phosphorus removal / recovery
facilities(Magnesium hydroxide)

To sludge
dewatering facility

239 m3/day(Digester)

Undiluted
solution tank(Digestive fluid)

Treatment
solution tank
ScreenReactorRecoveryequipment

ReForce Master (Phosphorus removal / recovery unit)

Sewerage
Science MuseumServicewater

To dryer

Cleaning
equipment

Dehydration
conveyor

Figure 5: Flow in Verification Facility(Phosphorus removal / recovery technology)

Outline of in-pipe installation typeInteriorunit

Construct simultaneously whenrenovating deteriorated sewers

Interior
unit

Heat utilization
facilities

Heat recoverypipe
Heat transport infrastructure

HeatInterior
unit

Water source
heat pump unit
Heat recovery facilities

Figure 3: Flow in Verification Facility (In-pipe
heat recovery technology)(3) Technology for removing and recovering
nitrogen and phosphorus derived from sludge
treatment(i) Technical empirical study on highly efficient
nitrogen removal technology for fixed bed type
Anammox process (Joint research organizationof Kumamoto City, Japan Sewage Works

Interiorunit

B17 floor
modulation

4. Future development
The NILIM will continue to spearhead verification
studies and in turn formulate guidelines on technology
introduction based on study findings, and promote thedissemination of guidelines.
[Reference]
http://www.nilim.go.jp/lab/ebg/index.htm