P-1865-OPP-Vodice rev1 sažetak engfvki.voda.hr/Documents/EIA_sve_transe/376-377.pdf · Suzana Mrkoci, dipl. ing. arh. Jakov Burazin mag. ing. aedif. Vedran Franolić, mag.ing.aedif

WATER PROTECTION

PROJECT : VODICE-TRIBUNJ-SRIMA

REQUEST FOR EVALUATION OF THE NEED FOR ASSESSMENT OF DRAINAGE AND WASTEWATER SYSTEMS ENVIRONMENTAL IMPACT

VODICE-TRIBUNJ-SRIMA

- summary -

Project No.: 6K-10412.3.1

Date of preparation: December 2011.

Project: WATER PROTECTION VODICE – TRIBUNJ - SRIMA

Commissioners: HRVATSKE VODE Zagreb, Ulica grada Vukovara 220

Client: Vodovod i odvodnja d.o.o. Šibenik Šibenik, Ulica kralja Zvonimira 50

The consortium for the project:

Manager and member of the consortium:

BRODARSKI INSTITUT d.o.o., Zagreb, Avenija Vjenceslava Holjevca 20

Member of the consortium

INSTITUT ZA EKOLOŠKI INŽENIRING d.o.o., Maribor, Ljubljanska ulica 9


TEHNOART d.o.o., Zagreb, Čakovečka 2


RAZVOJNI CENTER INŽENIRINGI CELJE d.o.o., Celje, Teharska cesta 40


IPZ Uniprojekt TERRA d.o.o. Zagreb, Babonićeva 32

The project manager monitoring

dr. Uroš Krajnc,dipl.ing., INSTITUT ZA EKOLOŠKI INŽENIRING Maribor,

Deputy project manager

Mario Panjičko, dipl.ing. BRODARSKI INSTITUT

IPZ Uniprojekt TERRA d.o.o. Babonićeva 32, 10000 Zagreb tel. +385 1 4635496 fax. +385 1 4635498 [email protected] www.ipz-uniprojekt.hr

IPZ Uniprojekt TERRA TD 80/11

TITLE: DRAINAGE AND WASTEWATER TREATMENT SYSTEM VODICE-TRIBUNJ-SRIMA evaluation of the need for environmental impact assessment

BEARER OF INTERVENTION: VODOVOD I ODVODNJA d.o.o., Šibenik COMMISSIONAIRE: HRVATSKE VODE CLIENT: BRODARSKI INSTITUT d.o.o. Av. V. Holjevca 20

10020 Zagreb CONCTRACT number: TD 80/11 IOD T-06-P-1865-1916/11 MANAGER: mr.sc. Goran Pašalić, dipl.ing.rud. PROJECT MAKERS:

IPZ Uniprojekt TERRA Danko Fundurulja, dipl. ing. građ.

Tomislav Domanovac, dipl. ing. kem. tehn.univ.spec.oecoing

Suzana Mrkoci, dipl. ing. arh.

Jakov Burazin mag. ing. aedif.

Vedran Franolić, mag.ing.aedif.

IPZ Uniprojekt MCF mr.sc. Goran Pašalić dipl. ing. rud.

Mladen Mužinić, dipl. ing. fiz.

Sandra Novak Mujanović, dipl. ing. preh. tehn.univ.spec.oecoing

Martina Cvjetičanin, dipl.ing.građ.

Director Danko Fundurulja, dipl.ing.građ..

Environmental protection elaborate – sewerage system and wastewater treatment Vodice-Tribunj-Srima evaluation of the need for assessment - SUMMARY

IPZ Uniprojekt TERRA TD 80/11

CONTENT

1. INTRODUCTION ......................................................................................................................... 1

2. PROJECT DESCRIPTION ........................................................................................................ 3

2.1. EXISTING CONDITION .................................................................................................................................. 3 2.2. THE SEWERAGE SYSTEM ............................................................................................................................... 5 2.3. WASTEWATER TREATMENT PLANT .............................................................................................................. 10 2.4. OFFSHORE OUTFALL ................................................................................................................................... 15

3. LOCATION OF THE PROJECT ............................................................................................. 17

4. POTENTIAL IMPACT ON THE ENVIRONMENT AND PROTECTION MEASURES ......................................................................................................................................................... 19

5. PROTECTION MEASURES .................................................................................................... 19

6. REQUIRED MONITORING PROGRAM............................................................................. 19

7. PUBLIC INVOLVEMENT ........................................................................................................ 20

8. CONCLUSION ............................................................................................................................ 20


IPZ Uniprojekt TERRA TD 80/11 str. 1

1. INTRODUCTION

In order to achieve the objectives of the Water Management Strategy, and to meet obligations arising out of alignment of national legislation with the EU acquis, in particular the Directive on municipal wastewater, and the construction of sewerage systems and wastewater treatment plant is neccessary for agglomeration resorts Vodice, Tribunj, Srima i island Prvić.

Given the substantial financial resources required for the project implementation - the construction of sewerage systems and wastewater treatment plant for agglomeration resorts Vodice, Tribunj, Srima i island Prvić, project intends to apply for co-financing of EU funds. Necessary precondition for EU funding is the plausibility of the proposed project considering the environmental impact.

For the public sewerage system project Srima-Vodice-Tribunj a procedure of the environmental impact assessment was carried out, based on an environmental impact assessment study (Faculty of Civil Engineering, Zagreb, 2003) followed by the Ministry of Environmental Protection, Physical Planning and Construction issued a decision on the project acceptability on April 2nd 2004 (UP UP/I 351-02/02-06/0020, Reg 531-05/4-STZ-04-9) (Appendix 1.).

Adopted environmental impact study relates to the procedure of building drainage system

Vodice-Tribunj-Srima with first degree treatment plant and offshore outfall. Request for evaluation of the environmental impact assessment refers to the construction

of sewerage systems and treatment plants at 2nd treatment level. The level of treatment is determined by the estimated size of the device and the sensitivity of the area in accordance with implementation of the EU directives.

For the sewerage and treatment system Vodice-Tribunj-Srima following documents were made:

− Conceptual design with the technical and economic optimization "Kanalizacijski sustav Vodice-Tribunj-Srima", Volume 1: Sewerage network (Hidroing d.o.o. Split, TD 004/07, April 2007.);

− Conceptual design with the technical and economic optimization "Kanalizacijski sustav Vodice-Tribunj-Srima", Volume 2: Wastewater treatment plant (Hidroing d.o.o. Split, Faculty of Civil Engineering, April 2007.).

− Conceptual and main design for the location permit "Uređaj za pročišćavanje otpadnih voda kanalizacijskog sustava Vodice-Tribunj-Srima I faza" (Proning DHI d.o.o. Zagreb) – Main design Certificate was issued (UP: 361-03/10-01/73, Reg: 2182/1-16-11-8)

− Conceptual design "Podmorski ispust sustava odvodnje Vodice-Tribunj-Srima" (Proning DHI d.o.o. Zagreb, TD 115/2009, March 2009.).

− Main design "Podmorski ispust kanalizacijskog sustava Vodice-Tribunj-Srima", University of Split, Faculty of Civil Engineering and Architecture, November 2010.

− Feasibility Study "Sustava odvodnje i pročišćavanja otpadnih voda Vodice-Tribunj-Srima", Razvojni center Inženiringi Celje d.o.o., 2011.

− Conceptual design "Dogradnja uređaja za pročišćavanje otpadnih voda aglomeracije Vodice-Tribunj-Srima", IEI d.o.o. Maribor, Naval Institute Zagreb, 2011.



Conceptual design anticipates the formation of a sungle drainage system with a central wastewater treatment plant located in Seline, north from the road Vodice-Tribunj and discharge of leachate into the undersea area of Zmajanski Channel.

A solution od I. degree purification and I. costruction phase was chosen with the Main design for wastewater treatment plant (N=22000 ES, Qmax=150 l/s) which implies application of microfiltration process with previous mechanical pretreatment on the coarse and fine grids, and a line of mud integrated within the microfiltration process with the expected chemical lime stabilization.

Given the need for changes in treatment level based on the Feasibility Study, a preliminary design was prepared "Dogradnja uređaja za pročišćavanje otpadnih voda aglomeracije Vodice-Tribunj-Srima" („Wastewater treatment plant device upgrade for agglomeration Vodice-Tribunj-Srima”) which defines the device that is the subject of this request.

In addition to the above, the following documentation is prepared or is in preparation: Conceptual/Main design

− PS "Vodice 1" with associated transformer station and incidentnim preljevom energy facilities – Main design

− PS "Vodice 2" with associated energy facilities and bypass – Main design − - Gravity Canal to "PS Vodice 2", which takes wastewater from the existing main

collector of the coastal resort Vodice – Main design − - Pressure pipe / gravity channel "PS Vodice 2" to PS "Vodice 1" - G − Pressure pipe from PS "Vodice 1" to LTP − gravity channel connector to LTP − gravity channel supply to PS "Vodice 1" − - "Connection SRC Račice to the sewerage system within the gravity catchment CS"

Vodice 6 " − "Fecal sewerage in JTC, section SRC Račice-rotor in Vodice − PS "Vodice 5" PS "Vodice 6" pressure pipeline and gravity collector − PS "Srima 1", gravity and pressure collector − PS "Srima 2" with pressure pipeline and gravity collector

Conceptual design − Secondary network Center-Blata (gravity channels V1-2, 3, 4 V2-2, 3, 4, V3-7, 8) : − " Wastewater discharge of island Prvić "

Through the Adriatic Project, the production of the following documents was commissioned (preliminary / main design):

− Pumping station (PS = PS – in all frames below) "Sovlje", pumping station "Tribunj 4", gravitational (SO-1, SO-2, SO-3, SO-4, T2-1, T"-3, T2-4, T2-5, T2-6, T4-1, T4-2) i tlačni kolektori (SO-T-PS, T4-T) – conceptual and main design

− - The main gravity collectors in the town center Tribunj (T2-7, T2-8, T2-9, T2-10, T2-11, T2-12, T1-1, T1-2, T1-3, T1-4, T1-5)

− - Transformer station, stable diesel generator and signal cable of the pumping station Tribunj 1



2. PROJECT DESCRIPTION

Procedure processed with this Elaborate relates to modification of treatment methods (wastewater treatment plant) for wastewater. Adjusting with EU directives and the negotiating positions of Croatia, with respect to the sensitivity of the sea there was a need to expand the device to the second treatment level (biological). It is about discharge of treated wastewater that has capacity above 10,000 PE in the coastal sea area for which the second degree of purification is intended.

Table 2./1 Basic differences between treatments processed in the Study and procedure according to this Elaborate

Basic parameters Study Elaborate

FACILITIES AND EQUIPMENT

The drainage system + NO CHANGE

Wastewater treatment plant + NO CHANGE

Sewerage system Prvić - + Offshore outfall + NO CHANGE

WORK TECHNOLOGY

Drainage system Method Dividing NO CHANGE

The level of treatment I II (III)

Pools within the Device OPEN CLOSED

CAPACITY

Maximum capacity of device 35.000 RS 44.000 RS

LEGISLATION

Project compliance with EU Directive NO YES

POTENTIAL IMPACT ON THE ENVIRONMENT

Identified potential environmental impact + NO CHANGE

2.1. Existing condition

Agglomeration area includes the densely populated area of the city and Municipality of Tribunj, which covers the most urbanized part of the county, with a significant part of tourism and a smaller share of the industry.

The area covered by the Agglomeration (settlement Vodice, Srima, Tribunj and island Prvić), the percentage of connection to the sewer network is low. Out of total 9403 residents to the sewerage system only 23% of the population is connected (so called PE).



In settlements inside and out of the Agglomeration there is no functional sewage system, which means a permanent presence of coastal sea water pollution and sea water quality at beaches, low sanitary standards of living and tourism.

The problem of the system disorganization is solved by directly discharging into the sea and the nearby canals, streams and septic tanks, which means that all the waste water from the catchment areas of the City of Vodice and the Municipality of Tribunj is discharged into recipients without any treatment.

Sewerage system Vodice - Wastewater drainage system coveres only a narrow part of Vodice (town), and the state of the system is very poor due to deterioration. The current system in the center of the town Vodice was mostly built of the old quadrangular channels (concrete or brick masonry channel), which are very transmissive, and will in the future need to be reconstructed. Of the existing sewer system facilities, which are in relatively good condition (newly built buildings from 2004), sewage collectors in the street Louis Gaja, Artina the street, in the street Kamila Pamukovića, coastal sewer extending from the marketplace to the hotel Punta, and at Ante Poljička can be sorted out. All channels that were built recently, mainly in the upper parts of the city, can be considered of high quality and can be used in future designs of sewerage systems. With these collectors, there are three pumping stations in the town Vodice.

Sewerage system Srime - In Srima there is no constructed sewage system, but wastewater is discharged into the sea through septic tanks.

Sewerage system of island Prvić - On the island of Prvić there are no sewerage installations, but the waste water is engaged into the sea through septic tanks. Only in some locations in the old city centers there is a sewage system on which a dozen objects are also linked and they have a common drain into the sea. It is likely that such installations are in poor condition and need replacement. On the island are two more places to include Prvić Luka and Prvić Šepurine.

Sewerage system Tribunj - In Tribunj there are buildings on the coast, with a small percentage of connection. These facilities are relatively new, and can be considered to be in good condition.



2.2. The sewerage system

It is anticipated to form a single drainage system with a central device for wastewater treatment plant, located in Seline, and the discharge of treated wastewater into the undersea area of Channel Zmajan. Such concept is consistent with the Study on environmental impacts and the Decision of the Ministry of Environmental protection to accept the Study. In addition, a common system is certified by The Regional Plan of the Šibenik-Knin Municipality (Official Journal of the Šibenik-Knin Municipality 11/2002 and 10/2005), Spatial Plan for the Town of Vodice (Official Gazette of Vodice 10/09), and the Study of water protection Šibenik-Knin Municipality (Hidroing doo Osijek and Hidroprojekt-ing doo Zagreb, 2000 g).

A proposal which retains the entire newly built or engineered sewerage network in town center Vodice, as well were given the fundamental determinants of long-term solution of common sewerage system Vodice-Tribunj-Srima passed:

− The sewerage system is of separator type;

− One common device for purification is provided, final capacity of 44,000 RS; − One common offshore outfall is provided, profile Ø500mm, length L = 2006 m;

− Sewerage network Tribunj is independent and has five pumping stations;



− Sewerage network Vodice is divided into two parts, and those are: o upper zone: the main transmission facilities are in a corridor and road D8 and

Vodice-Vodice, with two pumping stations, and o The lower zone: the main transmission facilities are at coast with four pumping

stations; − The sewerage network Srima, which has four pumping stations, is linked to the basic

facilities of the upper zone of Vodice; − Wastewater from the island Prvić, load 3500 RS, load RS 3500, adopted at

a common system in Vodice (in PS "Vodice 2") and remain transported by the main transportation facilities to the wastewater treatment plant.

The planned construction of the sewerage system consists of gravity channels, pressure pipelines and related pumping stations. The drainage system is designed as a separator, and only sanitary wastewater is treated on the device.

Frame 2.2./1 Schematic view of the sewerage system Vodice – Tribunj – Srima

Sewerage system Vodice

The sewerage network of the settlement Vodice is designed in a way that the lower range of Vodice is separately led by the facilities along the coast to the machine, and the upper zone of Vodice is separately drained by the facilities in a corridor and road D8 and Vodice - Tribunj. Srima is also designed looking up to the upper part system. Island of Prvić is designed similar to the lower zone system.

In the upper zone pumping stations are required Vodice PS 4, PS 5 and PS Vodice Vodice 6 and pumping station on the secondary system of Vodice- Račice.

The lower zone includes construction of pressure pipelines and gravity channels, through which the wastewater is transported to the device. The lower zone requires pumping stations Vodice- PS 1, PS 2 and renovation of pumping station PS Vodice- Vodice 3.



Pumping stations PS Vodice- PS 1, PS 2 and PS Vodice- gravity and pressure collectors to the device, collect the flow of wastewater along the coast to the west from the lower zone in Vodice and transport them to the device.

Pumping stations PS Vodice- PS 4, PS 5 and PS Vodice- Vodice 6 and gravity and pressure collectors to the device, collect the flow of waste water from the upper zone to the west of the settlement PS Vodice- and transport them to collectors in the road- PS Vodice- Tribunj to the device

Secondary sewage system collects wastewater flow of the population and the associated economy. It was designed mainly for streets and roads. For the area Račice a pumping station PS PS Vodice- Račice is planned.

The rehabilitation of the existing pumping station Vodice 3 is planned.

Frame 2.2./2 Schematic view of the sewerage system Vodice

Sewerage system Tribunj

Sewerage system Tribunj gravitates from west to east along the coast where the main pumping station is located Tribunj PS 1 which transports all wastewater at the pressure pipe to the device. It is necessary to build:

− 2 pumping stations, − gravity and pressure collectors in length of 9.660 m,

− pressure line to the device in length of 1.474 m.



Frame 2.2./3 Schematic view of the sewerage system Tribunj

Sewerage system Srima

Srima has no sewerage system. It is necessary to build:

− 2 pumping stations, − gravity and pressure collectors in length of 12.760 m.

Sewerage system Srima gravitates from east to west. Along the coast, primary gravity and

pressure collectors are predicted, they collect all the wastewater and transport it to the system of the upper zone of the pumping station Vodice, PS Vodice 4. Along the coast two pumping stations are located, Srima PS 1 and PS Srima 2. Secondary sewerage gravitates towards the coast from the north and is connected to the primary collectors.

Frame 2.2./4 Schematic view of sewerage system Srima



Sewerage system Prvić

Prvić has no sewerage system. It is necessary to build: − 5 pumping stations,

− − gravity and pressure collectors in length of 13.170 m.

Sewerage system of the island Prvić gravitates from south to north. Along the west coast the primary gravity and pressure collectors are predicted, and they collect all wastewater from the settlement of Prvić Luka and Šepurine. They use underwater pressure pipeline system to transport it onto Vodice lower zone system. Along the west coast four pumping stations are located: Prvić PS 1, CS 2 Prvić, PS 4 and PS Prvić Prvić 5. Predicted for the eastern part of the area along the coast are gravitational collectors and pumping stations Prvić PS 3, which transports wastewater to the pumping station Prvić PS 2 in the settlement Šepurine.

Secondary sewerage gravitates towards the coast and is connected to the primary collectors.

Frame 2.2./5 Schematic view of sewerage system Prvić



2.3. Wastewater treatment plant

The Study on environmental impact (a conceptual design) provided a device with a first degree of purification.. Since this method does not meet the current legislation it is necessary to provide the device with a secondary treatment in the first phase of building the system.

Analysis of all the features showed that the optimal solution is build a device that will work in two operating regimes. During the off season, when the work load of the device is low, the device is operating in a regime of aerobic biological sludge stabilization, and in the summer season when the load is high, the device operates in the regime of partial aerobic biological stabilization of sludge from the sump destabilization in the silo for sludge.

Due to the difference of hydraulic load and biochemical water level in the SBR tanks move off-season between 3.18 and 3.50 m depth of water, and while working in the tourist season between 3.18 and 5.50 m. In this way, with a different depth of water in the SBR tanks adjust the working volume of the tank. So the off-season biological unused capacity of the machine is relatively small.

Workload of biological sludge off-season is between approximately 0.023 and 0.045 kgBPK5/kgST/d (depending on the number of SBR tanks in operation - four tanks / two tanks), and during the tourist season the load of biological sludge is approximately 0.07 kgBPK5/kgST/d.

Therefore off-season, due to low load of biological sludge it is aerobically completely stabilized. In the tourist season there is a greater load on biological sludge and there is approximately 2 to 4 months a year extra aerobic sludge stabilization in sludge thickening.

2.3.1. Purification technology

The selected alternative provides the device with biological purification of wastewater, discontinuous flow of water in the biological stage, partial aerobic stabilization of biological sludge and separate aerobic post-stabilization of sludge in the sludge silo.

After mechanical pretreatment (input pump station, screens, grit and grease trap) wastewater is gravitationally fed into four cyclic SBR tanks with previous selectors (in the first phase of building tanks 2) where biological treatment wastewater takes place. From the SBR tanks, purified water overflows in a facility that measures the water flow and samples, collection continues in offshore outfall.

In the process of of biological wastewater treatment partially isolated aerobically stabilized excess sludge is pumped into the sludge thickener where is further aerobically stabilized. sludge from the thickener is pumped into the same system for sludge dehydration (centrifuge).

Polluted air from the water line and the sludge is discharged into the biofilter.



Frame 2.3.1./1 Tehnological scheme



Frame 2.3.1./2 Wastewater treatment plant



Water line From the flowmeter at the entrance of comes the water into the receiving part of the

electromotor grid. On the electromotor grid, from the wastewater, most of the large and fibrous material can be removed to protect other parts. Remains that are left behind on the grid are compacted in a spiral presses and unloaded in a container. After passing through the electromotive grid, wastewater is gravitationally lowered to a separator pane in two sand traps of different volume. Off-season water only passes through the lower sand trap, and in the summer season through both sand traps. In this way, water retention time in the sand trap can be partially controlled and excessive deposition of organic matter can be prevented.

After treatment in the sand trap and grease catcher, mechanically treated wastewater is discharged into the siphon tube that leads to the water distributor, SBR tanks. The plan envisages construction of four SBR tanks (two in the first stage, and the next two in the second - final stage). At the entrance of the SBR tanks are built selectors, so the cycle of SBR plant does not require an anoxic tank phase. Selector simplifies the process and provides a selection of biological microorganisms, which are capable of forming sludge flokules for different loads, especially for loads that are less than the designed load. The biological selector enables the run of shorter cycles compared to other SBR systems, which means smaller tanks and lower operating costs. Selector operates in anoxic to anaerobic conditions and easily biodegradable organic fractions of wastewater can be quickly removed by enzymatic mechanisms. The selector also provides selection of polyphosphatic microorganisms. The selector also reduces the formation of the filamentous microorganisms that cause the floating and foaming sludge very effectively. At the bottom of the selectors pipes are installed for occasionally stirring and draining sludge deposited in the selectors. The wastewater from the selectors flows into the main part of the SBR tank, working in cycles. Cycle duration is four hours, including charging and aeration of the tank is in progress for two hours, one hour of sedimentation and one hour of pool emptying. This part takes place simultaneous nitrification and denitrification.

During the filling and aeration, the tank is blown by compressed air. For this purpose at the bottom of the tank systems for blowing compressed air have been installed with fine air bubbles. During charging and aeration of the SBR tank, pump for sludge recirculation is working and it is pumping the sludge into the selector.

After completion of the loading phase and aeration of tank, begins the phase of deposition. At the end of the phase of deposition, excess sludge is pumped into the sludge thickener. At the end of discharging of the SBR tank, the decanter is rising to the top position and starts aeration and loading phase.

In each of the SBR tanks a meter of oxygen concentration is fitted, a water level meter, temperature meter and the required number of level switches. All equipment for the SBR tanks (except for the aeration system) can be serviced without the draining of the SBR tank.

The SBR tanks are covered with a reinforced concrete slab, protected with sand.

After the treatment in the SBR tank, purified wastewater is drained into the pipe leading towards the flow meter and samplers at the exit, and on to the "intermittent pane" of the offshore outfall. Purified water sample taking is provided in the facility. Output from "intermittent pane" begins offshore, and the outfall is running down to Tribunj, where it enters the sea in the marina area.

Sludge line The excess of sludge from the SBR tanks is pumped through the pumps in the sludge

thickener, which, because of work security, includes two tanks for sludge thickening. In the



sludge thickeners excess sludge is accumulated up to approximately 2.5% of dry matter. Sludge water separates into the internal sewage system via static overflow, and then is pumped into the receiving part of the electrical grid. To isolate sludge water from the lower part of the sludge thickener (below the current sludge level in the thickener) in both tanks one electromotorized strainer of sludge water is used, so that it can regulate the level of sludge water discharge.

In each tank a sludge mixer is designed for homogenizing the sludge prior to sludge dehydration and a self-priming aerator for any necessary aerobic stabilization of the sludge. The thickened exess sludge is pumped into a centrifuge for the sludge dehydration in the sludge thickener. With two dosing pumps (one as backup) polyelectrolyte solution is is pumped into the pipeline for the supply of sludge in the centrifuge. The centrifuge has a system for the automatic regulation of the differences in external rotation of the inner rotor, compared to change of concentration of dry matters excess of sludge at the entrance of the centrifuge. The flow of polyelectrolyte dosing pumps is controlled by changing the path of the pump. The tandem comes into the internal sewage system from the centrifuge, and dehydrated sludge is transported by two spiral transporters into a roll-off container with the volume of 30m3, which is givern to the licenced firm for waste collection.

The reception od sludge from septic tanks is preformed by cisterns. They empty the content of septic tanks through the reception and measured pipeline, into the input area of the reception tank. pH and flow of the content is measured. Reception of septic sludge includes a system for identifying carriers of septic sludge. In case of exceeding pH value, electromotorized valve automatically closes the flow of content from septic tanks from cisterns. At the exit from the entrance area of the reception tanks, electromotive grids are built to remove crude waste. On the electric grid, a presses is connected which washes and compacts septic waste nd throws it into the container of 4m3 volume. Reception tank serves as a reservoir of content of septic tanks and, if necessary, diluted with water from the sand traps. In purpose of homogenization of septic waste in the tank, a propeller mixer is built. After homogenization and possible dilution of septic waste, content is pumped into the inlet part of the sand traps by using a submersible special pump. The backup pump is in storage.

Polluted air is sucked from the pumping station, and is led to purify into the biofilter. Operation of the facility for receiving septic sludge is fully automatic.

2.3.2. Quality of treatment

Under existing regulations, given the drop area, the second degree of purification is required. The limit values of the parameters in waste water discharged into the natural recipients from the treatment after the second treatment level, are set forth in the following table:

Table 2.3.2./1 The limit values of the parameters in wastewater after the second treatment level

indicator Expressed as unit limit value

Suspended solids mg/l 35 COD O2 mg/l 125 BOD5 O2 mg/l 25 minimum reduction of burden of susp. substances % 90 minimum reduction of burden COD % 75 minimum reduction of burden BOD5 % 70-90



Biochemical and hydraulic loading of the device off-season will be the fourth of the load in the summer season so the level of treatment will be very high because of the decreased unit burden. The expected off-season value of indicators in wastewater are shown in the following table:

Table 2.3.2./2 The expected off-season value of indicators in wastewater

indicator expressed as unit limit value

suspended matter mg/l 15 COD O2 mg/l 60 BOD5 O2 mg/l 7 minimum reduction of burden of susp. substances % 92

minimum reduction of burden KPK % 88 minimum reduction of burden BPK5 % 95 total nitrogen N mg/l 15 ammonium nitrogen N mg/l 3 total phosphorus P mg/l 4

Therefore, the device will reach third degree of purification, with the exception of

purifying phosphorus off-season.

2.4. Offshore outfall

After treating the water in the leachate treatment plant, wastewater is disposed into the sea by offshore outfall. The plan envisages a tube profile DN 500/454.6 mm. The total length of the outfall is 3431 m 1425 m The first outfall is conducted by land, as far as Cape Rupa in Tribunj, where part of the offshore outfall begins. The route of the offshore outfall is approximately perpendicular to the shoreline. The first part of the route of the undersea outfall extends towards the west-southwest, from the coast to the passage between the island and Lukovnik Logorun, the in length of about 625 m. After passing through the passage between the island Lukovnik and Logorun, drain turns toward the southwest. Draft tubes length is 266 m, it begins at about 1740 m from the coast, and ends at a distance of 2006 m from the coast. The sea depth at the location of the draft tube is about 60 m. The sea depth at the location of the draft tube is about 60 m.

The application of long offshore outfall is rational with an adequate level of treatment, taking into consideration the proven ability to be self-cleaning as a tuner, and reduction of power of bacteriological contamination, which is difficult to eliminate through various technical - technological processes. The natural properties of seawater provide the ability of sea as a receiver, under certain conditions of release, taking part in the further degradation of organic matter, without any threat to the ecological stability of the marine environment at the discharge site. That is noticeable especially on smaller drainage systems.

The final direction and length of the offshore outfall is defined in hydrographic Study "The results of research work route offshore outfall wastewater public drainage resort Vodice - Srima - Tribunj" (HHI, August, 2003.). For the offshore outfall main project was made "Submarine outfall sewer system Vodice-Tribunj-Srima" (Civil Engineering and Architecture, University of Split, November 2010).





3. LOCATION OF THE PROJECT

The area covered by the project's spatial plan is Šibenik-Knin Municipality and the Spatial plan of the City of Vodice.

Frame 3./1 An extract from the the Regional Plan of Vodice - infrastructural

system



On the extract from the map of Croatian ecological network (Figure 3./2) it is clear that the area of the project is not located within the ecological network.

Frame 3./2 Extract from the map of Croatian Ecological Network



4. POTENTIAL IMPACT ON THE ENVIRONMENT AND PROTECTION MEASURES

All the potential environmental impacts were identified in the Study on the environmental impact and the procedure of environmental impact assessment. Since the change to the project is related to the changes to the treatment plant, in a way that it increases the level of treatment, it can be concluded that there will be no new impacts or to recognized impact will be smaller.

Environmental impact, due to the formation of unpleasant odors in the parts of the device (electromotive screens, sand traps and grease trap, SBR tanks with selectors, sludge thickening, sludge dehydration and acceptance of septic sludge) is reduced to a minimum since they are all designed as an enclosed building in which it maintains a negative pressure, and contaminated air will be purified through the biofilter before being discharged into the environment.

All waste generated on the site will be disposed of by licensed collectors. When issuing approvals and reviews of all industrial and craft drives that are connected

to the system or device (either through combined or separated part of the system) municipal company shall issue an approval which will set forth the obligation of organized, regular control of wastewater, as well as an obligation to the changes in the technological process of individual facilities that must obtain a re-thinking - consent, all to prevent the inflow of toxic and corrosive waters which could cause the device to stop functioning.

To relieve the consequences of device downtime or the individual parts, machine concept provides for a minimum of two independent parts of the same technological process for most of the device. System of valves, channels, passes the possibility of working parts of the device, with the elimination of damaged parts.

Energy supply of the device will be carried out from two independent sources (public electricity. Distribution and agregate) with automatic plugging.

As a fire-fighting measure in all buildings with an electro-mechanical equipment and electrical installations, for fire extinguishers "dry fire" in accordance with applicable standards and safety measures are designed due to the risk of explosion. On the plateau of the device, external hydrant network under applicable propisimaje is planned.

Constructing the offshore outfall will provide excellent sea water quality. Given the distance of the location of the device from housing facilities and the fact that

the device is largely located in an indoor facility, it is not expected to exceed the legal noise limits. Given the location of the pumping stations in the underground reinforced concrete structures can be concluded that it will not be affected by noise due to the same.

5. PROTECTION MEASURES

No need for a change of environment protection measures stipulated by the Decision MZOPUG UP / 351-02/02-06/0020, Reg 531-05/4-STZ-04-9) from 02 April 2004. (Appendix 1), which are involved in the conceptual design and that will be conducted during the construction and operation of the project.

6. REQUIRED MONITORING PROGRAM

Monitoring is prescribed by the Decision MZOPUG UP / 351-02/02-06/0020, Reg 531-05/4-STZ-04-9) from 02 April 2004. (Appendix 1) and no need to change it.



7. PUBLIC INVOLVEMENT

During the assessment process for environmental impact, a public debate was conducted through which the public is familiar with the procedure and had the opportunity to comment and suggest. In the course of a public hearing a public display was held, in which the Producer of the Study presented the intervention and answered questions.

8. CONCLUSION

Based on the Study on the environmental impact of the public sewerage system intervention, Srima-Vodice-Tribunj, the assessment procedure was carried out about the environmental impact on the basis of which the Ministry of Environmental Protection, Physical Planning and Construction of the 2nd April 2004, issued a decision on the acceptability (UP / 351-02/02-06/0020, Reg 531-05/4-STZ-04-9). Since the change to the project relates to increasing the level of purification, there will be no new impact on the environment and that already identified impact will be less severe. Protection measures and monitoring programs are prescribed to ensure environmental acceptability of the project.

Given the above, it can be concluded that the intervention system for sewage and agglomeration Vodice-Tribunj-Srima not need to conduct the assessment of the environmental impact.