AGGLOMERATIONS ZADAR AND

PETRČANE

Zagreb, 30.6.2016.

FEASIBILITY STUDY - DRAFT

Project area

• Zadar County, administratively: city of Zadar

• Project scope:

• WS & WW network

• WW treatment

Project base data

Agglomeration Zadar Petrčane

Population (2011.) 72.008 + 3.000 1.416

Tourism - overnights

20151.002.400 469.400

Tourism seasonality

July + August~55 % ~65 %

Total water consumption (m3/y),

2012 – 2015 average~4.900.000 ~200.000

Water consumption ratios (%)

households/tourism/industry68% / 27% / 5% 20% / 12% / 68%

Connection rate – WS ~99% ~99%

Connection rate – WW ~72% ~0%

Existing state – water supply

• Water intakes:

• Zrmanja river – main source

• Groundwater wells (secondary sources)

• Number of local intakes (auxiliary sources)

• Water supply system covers city of Zadar and 11

additional municipalities, including the suppy of several

islands

• Total network length – approx. 1.250 km

• 44 water tanks, 29 booster stations

• Total number of customers ~ 123.000Indicator Value

Total abstracted water

(m3/yr)28.976.000

CARL (m3/yr) 18.893.000

Real water losses - ILI 17

Non-revenue water 71,00%

Existing state – WS network

Northeastern direction of supply

(intake from Zrmanja)

Water tank Pudarica

Northwestern direction of supply

(intakes Jezerce, Bunari 4 i 5)

Water tanks Zadar I i Zadar II

Existing state – WW network

• 185 km of network + 20 PS

• Mostly mixed WW system

• 2 separate subsystems:

• Centre and Borik

• 2 WWTPs:• WWTP Centre

• 100.000 PE

• Secondary treatment

• WWTP Borik

• 15.500 PE

• Primary treatment

• Settlement Petrčane

• No public network

• 2 private networks withWWTPs (hotel complexes)

Existing state – identified issues

• Improvement of connection rates for agglomeration Zadar

• Insufficient connection rates a result of nonexisting system

• Around 25% of population doesn’t have access to WW system

• Hydraulic model of WW system showed bottlenecks in the system –

inadequate profiles

• 1,9 km of collectors to reconstruct

• Seawater intrusion in certain areas of Zadar (coastal collectors)

• Worst section identified in subsystem Borik

• 1,5 km of CIPP rehabilitation for coastal collectors included in STIP

• WW network and treatment in agglomeration Petrčane non-existent

Base design data

Agglomeration Zadar Petrčane

Population (2031) 76.900 + 3.000 1.500

Population consumption (l/cap/day) 110-140 110-140

Tourism - overnights 2031 ~1.260.000 480.000 (322.000)

Total consumption (m3/year)~5.185.000 ~235.000

Projected WW connection rates 90% 85%

WWTP load (PE)107.400 5.800

Recipient coastal sea - Zadar channel, "normal" sea

Treatment level required secondary "appropriate"

UWWTD deadline 2018 2023

Agglomeration extent – Zadar

• City of Zadar + settlement Crno

Agglomeration extent – Petrčane

• Settlements Petrčane and Kožino

Project scope and justification

- all agglomerations -

Measure Justification

WWTP in the project area Compliance with Urban Waste Water Treatment

Directive (91/271/EEC)

Compliance with requirements Croatian law

(Water Act)

• Implementation before end 2018/2023

• Normal area

• Minor upgrades on existing WWTPs to be

carried out

Extension of sewerage systems Increase the collection rate

Reconstruction of existing sewers Reduce sea intrusion

Improve hydraulic aspects

Reconstruction of water supply pipelines Impossible to avoid while constructing WW

network – estimate of 30% of WW network –

needs to be confirmed

Supervision Ensure supervision and FIDIC Engineer services

Project Management Mitigate lack of technical/administrative capacity

of the End Recipient

Option analysis carried out

Intervention Option analysis

WW network Pipeline routes in public corridors

Sewer rehabilitation based on CCTV records

No significant route options

WS network Pipeline routes in public corridors

No significant route options

WS reconstruction provided only for damaged

sections due to WW system construction (narrow

streets)

WWTP location for

agglomeration Petrčane

Two potential solutions analyzed

Sludge management and

disposal

Option analysis to be carried out

Preferred solution identified and quantified (for

discussion)

Option analysis – WW treatment for subsystem Borik

• Two main options considered:

• V1: Upgrade of WWTP Borik to secondary treatment (in accordance with

UWWTD)

• V2: Construction of transportation system from WWTP Borik to WWTP

Centre in Zadar and treatment on that location

• Comparison based on LCC (NPV, 30 years, 4% DR)

• In V1 – no available space for upgrade – not applicable

• 3 possible routes of transportation system analyzed

• Similar NPV results in all three proposed routes

• Route chosen due to comparative advantages with regards to installation crossings

(easy to build criteria)

• Mechanical treatment to remain in WWTP Borik – 5% reduction in

BOD calculated for loads coming into WWTP Centre

Option analysis – WW treatment for agglomeration

Petrčane• Two main options considered:

• V1: Construction of a new WWTP Petrčane, for capacity of 5.800 PE and

appropriate treatment level

• V2: Construction of transportation system to WWTP Centre in Zadar and

treatment on the existing location

• Comparison based on LCC (NPV, 30 years, 4% DR)

• In V1 – costs of WW network and CAPEX/OPEX of a new WWTP

• In V2 – costs of WW network, transportation system and OPEX for WWTP Centre

• V2 preferred and chosen

Recapitulation of variant solutions for agglomeration Petrčane NPV (HRK) Index

V1 –WWTP Petrčane 63.162.409

1,020WW system for settlements Petrčane and Kožino 40.288.768

New WWTP Petrčane, primary treatment (5.800 PE) 22.873.642

V2 – connection to WWTP Centre 61.937.665

1,000WW system for settlements Petrčane and Kožino 38.903.938

Transportation system from Petrčane to Zadar 19.979.308

OPEX for WWTP Centre (loads from agglomeration Petrčane) 3.054.419

Summary of loads on WWTP Centre

• Additional loads from subsystem Borik (5% reduction in BOD)

• Additional loads from agglomeration Petrčane

• Total calculated peak load – 110.000 PE (august 2031, seasonality factor

approx. 1,14)

• Nominal capacity of existing plant – 100.000 PE

• It is estimated that the existing plant can cope with exceeding loads (10% of

nominal capacity) in the projected period

• Exceeded loads are due to occur only in peak tourism season (10 days)

• If additional loads are to be received at WWTP Centre (agglomeration

Bibinje-Sukošan) upgrade would be necessary

200,00

225,00

250,00

275,00

300,00

325,00

350,00

375,00

85.000

90.000

95.000

100.000

105.000

110.000

115.000

120.000

1 2 3 4 5 6 7 8 9 10 11 12

l/sES

mjeseci

UPOV Zadar Centar - rezultati analize

Kapacitet (ES) Maksimalni satni dotok (l/s)

STIP summary

• WW system

• ~102,5 km of gravity collectors

• ~10,4 km of pressure pipelines

• ~5.300 connections (new)

• 20 pump stations

• WS system

• ~22,5 km of WS network (reconstruction due to WW construction)

• ~1.250 connections (reconnections)

• WWTP Centre and Borik

• Minor upgrades to WWTP Centre (no additional capacity)

• Replacement of ME equipment on WWTP Borik

Option analyses –sludge management

• To be fully carried out

• Sludge management

• preferred solution – transport to RWMC Biljane Donje

• FS for Biljani Donji took into account sludge disposal for

agglomerations Zadar and Petrčane

• Gate-fee calculated at 20€/tonne of sludge delivered to RWMC –

deemed as acceptable

• Transport from WWTP Centre to RWMC – to be included in this Study

Investment cost estimate

Component Investment estimate (HRK)

WW system construction/reconstruction – agglomeration Zadar 155.500.759

WS system reconstruction – agglomeration Zadar24.195.000

WW system construction/reconstuction – agglomeration Petrčane 64.435.427

WS system reconstruction – agglomeration Petrčane 6.893.000

SUBTOTAL 251.024.186

Supervision 12.551.000

Project Management 5.020.000

Visibility 750.000

Equipment supply 0

Contingencies (10%) 26.934.519

TOTAL (HRK) 296.279.705

Retrofit investments on WWTP Zadar Centre

1. Septic equalisation tank

2. Upgrade of odour treatment

3. Grit/grease trap and primary settlers to be covered

4. Replacement of diffusers in bioreactors

5. Technical water system to be added

6. Floating sludge issue

7. Potential for anaerobic sludge digestion