OPERATIONAL INFORMATION REQUIREMENTS

CONTENTS:

Drawing No. 11 58-2462

Drawing No. 11 58-2463

Outline Description of the Treatment Processes at Dundalk WWTP & Agglomeration

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

WWTP SlTE BOUNDARY l PRIMARY DISCHARGE

STORM OVERFLOW WATER

DISCHARGE POINTS

N O T E S

t RGUREO OIMENSIMIS MILY TOBE TAKEN FRM~M~S omwlrn

2 AIL DRAWINOS TOBECHECKED B I M E CMITPACTOR OXSITE

1 ENWNEER TOBE INFORMEDBY THE COMR*CTOROFANY DISCREPANCIES BEFORE AWWORKCOMMENCES

4 ALLLNELSSHOWN REUTETOORONANCE SURVEY DATUMATMALIN HEAC

,msmTocLEM,

I Cl-

LOUTH COUNTY COUNCIL I DUNDALK WASTE WATER

DISCHARGE LICENCE APPLICATION

I- : PLANT PROCESS I I SlTE PLAN

( SECTION / ATTACHMENT '2.1)

~vrdav DEC '07

Po(.dD*aal: MlCHAEL F. GARRICK

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

A OUTFALLTO I CASTLETOWN I RIVER ESTUARY

SETTLED STORMWATER OVERFLOW ,------------+--------------+-----------p------- CASCADE CHAMBER

I I

I STORMWATER HOLDING TANK I

( 4 CELLS I I FINAL EFFLUENT 9 SAMPLING

PROCESS WATER PUMPING STATION

/ 3.NO. FIRST STAGE AERATION BASINS / V'

FOR OFF-SITE DISPOSAL

---U

PUMPING STATION STATION

I TREATED SLUDGE FOR

OFF-SITE DISPOSAL

C"en t ' :LOUTH COUNTY COUNCIL Prepared by: R.K.

TOBIN Consulting Engineerr. L"' , m Market Square. CasUebar.

N O T E S I I I l

1. FIGURED DIMENSIONS ONLY TO BE TAKEN FROM THIS DRAWING N Co. Mayo, Ireland.

, , tel: +353-(0)94-9021401

iob,n BCo fax:+353<0)94-9021534 e-mail: castlebar@tobin.ie

m ConoulUw Englnnn dl not b. Rat4 for any u.. d W8 docvmmt lw my p- oUur thm thd for w h M It .m nl~imb w n d ond pro*ldd. Exapt .h- .pd(lcdh ."d olpnw W& in wm!w 4 TDWN Conwww Enplnm. 0s M h t holder. no wrt d lhb r!mum.d mq b. +mad W h ~ r n l t t . d in ow i o n and m* d o s u r n , *m,, not b. d . d "pm 4 ony thW v* tor any v u w .

Drawing No.: 11582463 Pmject: Checked:

DUNDALK WASTE WATER MFG Date:

DISCHARGE LICENCE APPLICATION ~ ~ 0 7 - w.tobin. ie

Revision:

2. ALL DRAWINGS TO BE CHECKED BY THE CONTRACTOR ON SITE -.

Title: Project Director:

PLANT 1 PROCESS FLOW DIAGRAM M.GARRICK

( SECTION 1 ATTACHMENT C.1 Scale @ A3: N.T.S.

3. ENGINEER TO BE INFORMED BY THE CONTRACTOR OF ANY DISCREPANCIES BEFORE ANY WORK COMMENCES A 07-12-07 ISSUE TO CLIENT R.K. E.S.

l I I I 4. ALL LEVELS SHOWN RELATE TO ORDNANCE SURVEY Rev I Date I Descn'ption I By I Chkd. DATUM AT MALlN HEAD

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

OUTLINE DESCRIPTION OF THE TREATMENT PROCESSES AT DUNDALK WWTP & AGGLOMERATION

1.0 DESCRIPTION OF THE TREATMENT PROCESS AT DROGHEDA

Raw sewage arrives at the Preliminary Units from Quay Street, Boyle O'Reilly, Coes Road, St. Helenas Park and Point Road Pumping Stations via four Rising Mains. At the Preliminary Units, separation of stormwater from flows intended for full treatment takes place, and flow is screened and degritted.

Overall the Treatment Process involves two stages of Aeration and Clarification, the first being a highly loaded stage, the second by contrast operates on a low biological loading. There are consequently two independent cycles of Sludge Return for the First and Second Aeration Stages as well as two separate sludge wastage installations. Scum

l removal however takes place at the Second Stage Clarifiers only.

Flows arriving at the Treatment Works lnlet Chamber will pass a Stormwater Overflow area where all flows in excess of 2.7 times DWF will be decanted to Stormwater Holding Tanks via a screened overflow before being returned for Treatment when main line flows permit.

Settled stormwater in excess of the 5000 cu. m capacity of the storm water holding tank flows in a stormwater pipeline routed along the northern site boundary where it joins the treated effluent flow downstream of the final effluent sampling point, discharging to a combined 900mm diameter Stormwater and Treated Effluent Outfall pipe to the Castletown Estuary.

The raw sewage from the lnlet Chamber passes through two screening units and all screenings over 5mm in size are removed from the flow, dewatered and transferred to a disposal skip. Following screening, grit is removed from the flow in a separate process.

The flow for full treatment then passes from the Preliminary Units to the Flow lnlet Chamber of the First Stage Aeration Tanks.

At the First Stage Aeration Flow lnlet Chamber the main flow for full treatment divides equally into two streams in Phase I (this will become three in Phase 11); each stream consists of one Aeration Lane and one First Stage Clarifier.

Sludge is returned continuously from the First Stage Clarifier to the First Stage Aeration lnlet Chamber via the First Stage Sludge Return Pumping Station. Effluent from the First Stage Clarifiers is taken to Flow Splitting Chamber No. 1 where Second Stage Return Sludge and First Stage Clarified Effluent are thoroughly mixed before entering the Second Stage Aeration lnlet Chamber.

The flow at this point again divides into three Aeration Lanes with the oufflow from this stage being split at Flow Splitting Chamber No 2 over two Second Stage Clarifiers in Phase I, rising to three Clarifiers in Phase II.

Sludge is returned continuously from the Second Stage Clarifiers via the Second Stage Sludge Return Pumping Station, which also houses Sludge Wastage Pumps.

Excess sludge is pumped to one of the two Sludge Prethickening Tanks. The sludge from these Thickening Tanks is pumped to the Sludge Digesters, with digested sludge

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

withdrawn to the two Post Digestion Holding Tanks. Sludge from the Digested Sludge Holding Tanks is pumped to Sludge Decanters located in the Sludge Dewatering Plant House. Dewatered sludge can subsequently be dried, if the disposal route requires biosolids in that form.

Final effluent is drawn from the Second Stage Clarifiers via peripheral weirs and is discharged via a final effluent chamber to the Castletown River Estuary.

A Final Effluent Flow Meter is located on the outfall pipeline. It is situated up stream of the Process Water Pumping Station (which delivers final effluent for use as Process Water) and measures final effluent flow from the Treatment Works.

l. I STORMWATER RETENTION

Gross solids are removed from the stormwater and retained in the main flow at the Preliminary Units prior to diverting stormwater via an Overflow to the adjacent Stormwater Holding Tanks. The Stormwater Tanks are designed on the basis of retaining the volume of surplus runoff generated in a four-hour storm for a return period

) of 1 year. The Tanks are constructed as four cells with sequential filling from one to another, with overall volume 5000cu.m. When storm conditions abate, the retained stormwater is released to an adjacent Stormwater Pumping Station and is pumped forward to the Preliminary Units. When the Stormwater Tanks are empty, they are flushed clean by means of a tipping bucket system. The tipping buckets are filled with final effluent and when an adequate volume fills the tipping bucket, the contents are released to provide a high velocity scouring action to the tank floor, leaving it clean until such time as the next storm event occurs. Return pumps are rated at 500m3/hr, with 2 duty 12.5kW units, so as to empty the tanks in 10 hours.

1.2 PRELIMINARY TREATMENT

Flows for full treatment (2.7 DWF, 565 11s) continue from the Inlet Chamber to the Preliminary Units proper. At the Preliminary Units, the raw sewage is first screened through 2 No. fine band screens with a mesh size of 5mm. Grit is subsequently removed when flow passes through a grit trap. The screenings removed from the flow at the Preliminary Units are washed, at 1 11s per metre of screen width dewatered and compacted for subsequent removal to landfill. Grit removed from the flow passes through a Grit Classifier and once dewatered, is discharged to a skip for subsequent

1 disposal.

The screening and grit removal areas are covered by means of an industrial type steel framed building and chequer plating to mitigate potential odour problems at the Treatment Works. Foul air from this building is scrubbed using a Biofilter prior to its release to atmosphere.

Following Preliminary Screening and degritting, the flow passes onwards to the First Aeration stage of the process. A higher sludge loading and a relatively lower hydraulic retention time is employed in this stage of Aeration than in the following Second Stage. Air is delivered at between 4329 and 5402 cu.m/hr from 2 duty and one standby air blower units.

1.4 FIRST STAGE CLARIFICATION

When First Stage Aeration of the effluent has taken place, it flows gravitationally over a weir to a Basin Outlet Chamber where it is divided over two 30m diam. First Stage

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

Clarifiers. It is estimated that 25% to 30% of the B.O.D. load and 55% to 60% of the suspended solids load is removed from the effluent at this stage.

First Stage Sludge is drawn off to the First Stage Sludge Pumping Station adjacent to the First Stage Clarifiers. First Stage Sludge is returned to the First Stage Aeration Basin Inlet Chamber, by 2 duty and 1 standby pumps while Waste First Stage Sludge is pumped forward to the dedicated First Stage Sludge thickener, (also by 2 duty and 1 standby pump) where it is thickened and subsequently pumped forward to the Anaerobic Sludge Digestion stage followed by dewatering.

The entirety of the First Stage Clarifiers are covered to mitigate potential odour problems at the Treatment Works. Foul air from First Stage Clarifiers is drawn through the aerators of the First Stage and then the exhausted air is scrubbed through a Biofilter Unit, which is located, adjacent to the Stormwater Holding Tanks.

1.5 SECOND STAGE AERATION

Following First Stage settlement, the flow passes onwards to the Second Aeration stage 1 of the process. A lower Sludge Loading is employed in this stage of Aeration than in the

First Stage. Air is delivered at 8157 cu.mlhr, from three duty and one Standby Blower.

Process air is transferred to both the First and Second Stage Aeration Basins via a Fine Bubble Diffused Aeration System, which in turn is sewed by means of Centrifugal Blowers located in the adjacent Main SwitchgearlAir Blower Building.

1.6 SECOND STAGE CLARIFICATION

Flow from the Second Stage Aeration Basins enters a further Flow Splitting Chamber (Flow Splitting Chamber No. 2) where it is equally divided between each of the two 43.lm diam. Second Stage Clarifiers.

Scum from the Second Stage Clarifiers is discharged by gravity to the Second Stage Scum Pumping Station and is subsequently returned to the Preliminary Units.

1.7 SLUDGE THICKENING, DEWATERING AND DIGESTION

Separate Sludge Thickeners are provided in respect of both First and Second Stage I sludge.

Sludge is held in the Digesters for a period of 20 days at 35°C. A proportion of the digested sludge can then be stored for a further period of 15 days in the digested sludge storage tanks. Plant operatives then have the option of either tankering away the digested sludge in liquid form or alternatively pumping it foward for subsequent dewatering by centrifuge and transfer onwards to the sludge drier.

The dewatered cake is pumped to seven storage skips for off site transport.

The entire sludge thickening, dewatering and digestion facilities have been designed to allow flexibility in the handling and disposal of sludges and keep the options of the Dundalk Urban District Council open with a view to streamlining their overall sludge disposal policy to match the overall sludge disposal strategy for County Louth.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

2.0 DESCRIPTION OF THE PUMPING INSTALLATIONS AT DUNDALK

2.1 ST. HELENA'S PARK PUMPING STATION

St. Helena's Park Pumping Station is located in St. Helena's Park near the junction of St. Mary's Road and Castle Road.

The Main Drainage system draining to this Station is a combined sewerage network. A 1600 X 9OOmm egg shaped sewer enters a manhole which diverts flow through a 900mm sewer to the Pumping Station and provision is made at this manhole for emergency by- pass of flows to the Castletown River by means of a high level overflow.

There are a total of six pumps installed in the Station, four pumps and two Storm pumps.

Three pumps operating together can deliver approximately 4.5 times DWF and the pumps are interchangeable as duty pumps, with one standby unit. The pumps discharge through a single 450mm diameter Rising Main which has an approximate length of 3140m. The Rising Main runs along Point Road, and discharges to the Preliminary Units

l of the new Waste Water Treatment Plant.

The stormwater pumps discharge through a storm outfall pipe to the Castletown River.

2.2 BOYLE O'REILLY PUMPING STATION

Boyle O'Reilly Pumping Station is located to the eastern side of Boyle O'Reilly Terrace and behind St. Nicholas Avenue. The main drainage system discharging to the Pumping Station is combined and the inlet sewer is 1050mm in diameter. At the inlet manhole to the Station, there is an emergency overflow pipe to the Castletown River. The pumping station has four dry weather flow pumps installed and has a single storm pump installed. The four foul sewage pumps are rated so that three pumping together can deliver approximately 5.5 times DWF, the third unit being a standby pump.

The foul pumps discharge through a 600mm diameter A.C. Class 15 Rising Main of an approximate length of 4150m to the Preliminary Units of the Treatment Plant.

There is a single storm pump in this Station, which cuts in on a high level in the wet sump when all duty foul pumps are already running. Stormwater is discharged through a

) 600mm diameter Rising Main to a storm overflow chamber on the Pumping Station site, from where it discharges gravitationally through a 600mm diameter storm overflow pipe to the Castletown River. The duty point for the Storm Pump is 2,710 rn3/hr. at a head of 5.9m.

2.3 COES ROAD PUMPING STATION

The Coes Road Pumping Station is located near the junction of Coes Road and the Inner Relief Road, and within the Coes Road Industrial Estate.

Combined flows enter the Pumping Station through a 1500mm inlet pipe and pass through a screening chamber

There are four pumps in the foul sump with space for the provision of a fifth pump, which is planned to be installed within the next two years.

The four foul sewage pumps are rated so that three pumping together can deliver approximately 4 times DWF, the third unit being a standby pump. The addition of one further pump will bring the transfer capacity to 4.6 times DWF, and it is also intended to

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

install and commission a stormwater balancing tank on the Coes' Road site within the next two years.

There is one stormwater pump in the station, rated at 2300 m3/hr, which delivers to a pipeline routed to the Castletown Estuary.

2.4 QUAY STREET PUMPING STATION

Quay Street Pumping Station is located at the rear of the houses along Quay Street on the opposite side of the Road to the A n y Barracks

There are three foul pumps in the station, two duty and one standby. Two units pumping together can deliver just over 2 times DWF to the Rising Main in Quay Street, which runs to the wastewater Treatment Plant at Soldiers' Point.

One stormwater pump, rated at 3 times DWF, cuts in on a high level probe in the wet sump, and discharges to the nearby Castletown Estuary.

) 2.5 POINT ROAD PUMPING STATION

Point Road Pumping Station serves a small catchment mainly consisting of ribbon development along Point Road from the junction of Point Road with Red Barns Road on its western extent, as far as the coastline to its eastem extent.

The Station is located on the southern side of Point Road near the river Blackwater. The Pumping Station consists of an inlet sewer to a wet sump measuring 1.7m wide by 3.6m long. There are three submersible pumps installed, two dry weather flow pumps, one duty, one assist and one standby pump.

2.6 TOBERONA PUMPING STATION

The main equipment provided within the Toberona Pumping Station is as follows:

1. Pumps: A total of three units are provided, 1 duty 1 assist 1 stand-by All are similariy rated and manufactured by HOMA Model V2446-P94EEX Duty 75m3/hour at 12.9rn head

2.7 NEWRY ROAD PUMPING STATION

Newry Road Pumping Station is located off the old Newly Road on the right hand side as one proceeds northwards out of Dundalk. This station serves a small catchment area surrounding the townland of Red Cow, which is partially pumped and then flows by gravity to St. Helena's Catchment.

The Plant contains a small submersible pump in the drywell and 2 No. pumps - 1 duty and 1 standby which discharge through a 100mm ductile iron rising main

2.8 PIERSE PARK PUMPING STATION

This Station is located on the Pearse Park green next to the sorting office of the Post Office.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30

It consists of 2 No. pumps in a dry well, 1 duty and 1 standby, with the duty unit discharging through a 200mm rising main and the standby unit discharging through a 150mm ductile iron rising main.

Pearse Park Station in turn discharges to the St. Helena's Pumping Station subcatchment.

2.9 MACARDLE MOORE/CIE BREWERY PUMPING STATION

Mac Ardle Moore Pumping Station is located opposite the old brewery, at the back of Moffits Forklifts Factory. It consists of an underground pumping station with 2 No. submersible pumps both discharging through 100mm ductile iron rising mains to the head of the nearby gravitational section. A 200mm inlet enters the chamber and the pumps are operated on a float system, which cuts the pumps off and on.

3.0 ONSITE LABORATORY FACILITIES

1 Dundalk WWTP has an onsite laboratory facility, which is managed by a full-time chemist.

On a daily basis, the chemist collects a composite sample of the incoming effluent and treated primary discharge and analysis the samples for:

COD Clarity

On a twice weekly basis, the chemist collects a composite sample of the incoming effluent and treated primary discharge and analysis the samples for:

. BOD Suspended Solids Dry Solids pH

On a monthly basis, the EPA Laboratory (sub-contractors to Louth County Council), ) independently collect a composite sample of the incoming effluent and treated primary

discharge and analysis the samples for:

COD Clarity BOD Suspended Solids Dry Solids pH Total Nitrogen Total phosphorus

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 25-07-2013:23:38:30