CaseManagement of a drainage treatment facility through PFI

Water utility

Kanagawa Prefectural Enterprise Agency

General information of the utility (as of 2021)
Operation

Public (retail waterService areatypesupply)(km2)

Population

Distribution

2,844,676

served809 ㎢
878,137 ㎥/d(m3/d)Servicecoverage

99.8％

Pipe length (km)9,406km8.4％

Number of staff

615(%)NRW (%)
Number ofwater

Surface water (6), Groundwater (0), Others (6)sourcesWater(in case of 10m3 of water per month for966

rates (JPY)

residential customers with 13mm diameter)

After more than 30 years since its construction, the drainage
treatment facility at the Samukawa Water Treatment Plant, the main
water treatment plant of the Kanagawa Prefectural Enterprise Agency,
had been due for renewal (Figure-1).
Therefore, the PFI method (BTO method) was introduced for therenewal of the facility, utilizing private-sector know-how to (1) promote
more efficient and effective facility development and operation, and (2)stabilize the recycling of dehydrated cakes generated from thetreatment of drinking water sludge over the long term.
Coa g u la n t in j ector

Sod iu m h yp och lorite d isin fection fa cility

WTukuia ku i lakela ke

Summary

D istrib u tion reservoir
Su lfu ric a cidin j ector

Floccu la tion

Sa g a m iriver

Sed im en ta tion

Sed im en ta tion

Filtra tion

Tra n sm ission
pum p

Ra p id m ixin gPFID ra in a g e trea tm en t fa cility

Sa m u ka w ain ta ke

I n ta kepum pClea rw a terta n k

D eh yd ra tin g fa cility

D eh yd ra ted ca kesCon d en sa tion
fa cility

Fig u re 1 W a ter trea tm en t flow

PFI is a method of public works in which private-sector funds,
management capabilities, and technical expertise (know-how) areutilized to design, construct, renovate, and renew public facilities, andto maintain, manage, and operate them.
In the Samukawa Water Treatment Plant Drainage Treatment Project,
the prefectural government maintains, manages, and operates thewater treatment facilities, while the PFI-contracted company designs,
constructs, maintains, manages, and operates the drainage treatmentfacility based on the contract. The company also procures funds for theconstruction of the facility by obtaining loans from financial institutions(Figure 2).
Sa m u ka w a W TP

Ma in ten a n ce & op era tion
Ka n a g a w a
Prefectu re

Service fees

Trea tm en t
fa cilities

Trea tmen t
Slu d g eService p rovision

con tra ct

Fin a n ces
Fin a n cia lin stitu tion sClea n
w a terD esig n & con stru ction
Ma in ten a n ce & op era tion
Fin a n cia lcon tra ct

PFI con tra ctor

D ra in ag e fa cility

p a yb a ck
Su b con tra ct

Fin a n ces

D eh yd ra ted ca kes

I n vestin g
com p a n ies

Recyclin g m a rket

1 0 0 % recycle

Fig u re 2 Bu sin ess sch em e

In introducing the PFI project, a basic concept was formulated in
FY2001, and a feasibility study was conducted to confirm the project
was compatible with the PFI method.
After the announcement of its implementation policy, the statutory
procedures were made such as VFM (Value for Money) evaluation andselection of the project undertaker through general competitive bidding.
Subsequently, the project contract was concluded with a special
purpose company (SPC), Samukawa Water Service Corporation, fromDecember 2003 to the end of March 2026.
After the contract was signed, it took about two years to complete theconstruction of the dewatering machine and other facilities, and the PFI
operator began operating the facility on April 1, 2006.
Currently, 20 years have passed since the contract was signed, andthe project has achieved the above-mentioned objectives (1) and (2).

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1. Current status (achievement level of PFI objectives)
In the effectiveness verification conducted in FY 2012 for the PFI
contract, its economic efficiency was proven through VFM evaluation(Table-1), and its effectiveness has been confirmed for efficient facility
development and stable operation.
(1) VFM evaluation
Table 1 Comparison of Project Costs, VFM, etc.

Current
Status &Challenges(2) Efficient facility maintenance
The use of a short-time dehydrator has leveled out the sludge
receiving load.

The introduction of a filtration/concentrator has enabled the facility
to cope with fluctuations in sludge concentration.

The facility is equipped with a space for future use to improve theconvenience of equipment renewal.

(3) Stable operation
Before the introduction of PFI, dewatered cakes used to be reused
only as a raw material for cement, but after the introduction of PFI,
they have been reused as gardening soil and ground soil in addition tocement raw material, thus securing multiple uses and sales channels(Figure 3).
The PFI contractor is contributing to the stable operation of the water
treatment plant by responding to market fluctuations in the reuse ofdehydration cakes.
They also have not defaulted on its services or reduced the service
purchase fee by applying penalty clauses such as the control of theturbidity of returned water, which is stipulated in the contract.
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W TP

D rin kin g w a ter

Fa cility ren ew ed via PFI
Slu d g e

D eh yd ra tor b u ild in g

Con d en sa tion p rocess

Con d en sa tio
n fa cility

D eh yd ra ted ca kes

D eh yd ra tor

Ma teria l su ch a s
cem en t
D rierClea r w a ter
Retu rn in g
p it

Ca ke ya rd b u ild in g

Grou n d soil

Sep a rated
w a ter
D rierExistin g con d en sin g
fa cility

D ried ca kes

g a rd en in g soil

H ig h -Sp eed Fib er
Filtra tion SystemFig u re 3 D ra in a g e trea tm en t flow

2. Issues
Measures toward the end of the PFI projectWith the expiration of the PFI contract, the existing facilities will betaken over to a new management format while still operating, and theoperational know-how must be appropriately transferred between theold and new management formats.
Actions Toward the Termination of PFI Projects
In preparation for the termination of the PFI project at the end ofFY2025, the Agency established a study group within the Agency inFY2022. Through a review and evaluation of the project, the study
Measures &Solutionsgroup will sort out the issues that have been raised so far, and properly
evaluate the project in reference to the "Basic Ideas on Post-evaluationof PFI Projects" published by national government in FY2023 for PFI
promotion.
Based on the results of the evaluation, the Agency will also proceedwith a study to establish the next management format, taking into
account the issues that have arisen in operating the current project.
Based on the results of the ex-post evaluation, to be conducted in
FY2023, the Agency will study the most appropriate management
format to operate the Samukawa Water Treatment Plant from among

Future Plans

various formats, including PFI, comprehensive outsourcing, individual
outsourcing, and a designated manager system.
From FY2024, the Agency will start preparing publicly solicitedmaterials for the next management method, and smoothly hand over tothe next management format from FY2026 to continue the stable
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operation of the drainage facility.
Drainage Treatment Facility at the Samukawa Water Treatment Plant
References

https://www.pref.kanagawa.jp/docs/gh8/management/samukawa.html

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