Phase 2 Detailed Design Review 7 November 2006

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Phase 2 Detailed Design Review 7 November 2006
BEACHLANDS-MARAETAI WWTP UPGRADE
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DESIGN INTRODUCTION

• Meet or exceed consent conditions
• Design from 4,300PE to 10,000PE
• Best available technology
• Minimizing whole life costs
• Valued asset for the future

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CONSENT DISCHARGE QUALITY
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DESIGN FLOWS
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DESIGN INFLUENT QUALITY
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PROCESS FLOW DIAGRAM
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WASTE SOLIDS FLOW DIAGRAM
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3mm SCREENS

• New Hydropress SSL 2000x865x3 3mm step screen
• Sindico SP150/900 screw press dewatering
• Rock trap prior to screen
• Existing 3mm step screen as standby

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VORTEX GRIT REMOVAL

• New 270 vortex grit removal system
• Huber RoSF3 LOC Coanda grit classifier

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BIOFILTER

• Air ducting from inlet works to biofilter for the
  removal of malodorous air
• Duty/standby Extraction fan

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STORM FLOW BUFFER

• New 6000m3 flow buffer
• Existing actuated control valves
• Mixing and aeration as required
• Duty/standby variable speed submersible pumps
• HDPE lined with concrete step access
• Manual cleaning with hose reels

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BIOLOGICAL PROCESS LAGOON ZONES
Anoxic Zone 1
Post-Denitrification Zone 5
Anoxic Zone 2
Reaeration Zone 6
Anoxic Zone 3
Aerobic Zone 4
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BIOLOGICAL PROCESS LAGOON FLOWS
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BIOLOGICAL PROCESS LAGOON INPUTS
Secondary Treated Wastewater
Alum
Screen Wastewater RAS Return Flows Biofilter
Drainage Storm Flow Buffer Methanol Lime
Methanol
Internal Recycle
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AERATION SYSTEM DESIGN 4300PE
NO3-
pH
DO
DO
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AERATION SYSTEM DESIGN 10,000PE
NO3-
pH
DO
DO
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BIOLOGICAL PROCESS DESIGN PARAMETERS
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CLARIFIER

• 16m diameter
• 4.5m sidewall depth
• Sludge and scum scraper
• RAS pump station
• Scum pump station

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POST TREATMENT BUFFER

• Approximately 9,700m3
• Post treatment buffer return pump station
• Effluent Flow Control Valve
• Maximum daily discharge reached
• High flow
• Low flow

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DISK FILTER
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UV DISINFECTION

• WEDECO UV Disinfection System
• 2 open channels
• 4 banks of 24 lamps

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CHEMICAL DOSING SYSTEMS

• Methanol
• Denitrification Zone 5
• Anoxic Zone 1
• Lime
• Anoxic Zone 1
• Alum
• After biological treatment
• Pre-filtration

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CHEMICAL DOSING SYSTEMS
Minimum is based on good quality return flows and
average conditions Maximum is a one day rate
based on poor quality return flows and peak
conditions
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ANAEROBIC DIGESTER STAGE 1

• Reconfigure PALs 1 and 2
• WAS introduced
• Introduction of Kawakawa Bay WWTP sludge into
  Stage 1
• Mixing/Aeration as required
• Lime Dosing
• Supernatant overflows to Supernatant Pump Station

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FLUMP

• Automated sludge removal from stage 1 to stage 2
• Also provides sludge mixing

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ANAEROBIC DIGESTER STAGE 2

• Receives partially digested and consolidated
  sludge from stage 1
• Mixing/Aeration as required
• Supernatant overflows to Supernatant Pump Station
• Sludge is manually removed for dewatering after
  liquid layer is removed

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SRTs FOR DIGESTERS
Allows one week for sludge transfer
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SAND DRYING BED

• 3 sand drying beds
• 200mm thick sludge depth
• Dewatered to gt20 dry solids

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RETURN FLOW PUMP STATIONS

• Supernatant Pump Station
• Return supernatant from Anaerobic Digesters to
  Biological Process
• Transfer supernatant from stage 2 to stage 1
  during sludge transfer operations
• Return Flows Pump Station
• Disk Filter backwash water
• Sand Drying Bed filtrate

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REUSE WATER PUMP STATION

• Provides reuse water for process requirements and
  wash down
• Fill pump
• Storage tank
• Booster pumps

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CONTROL SYSTEM

• PLC
• SCADA
• Telemetry

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CONSTRUCTION

• Stage 1 Off line Inlet works and Storm Buffer
• Stage 2 Offline construction of clarifier,
  pumping stations, tertiary filter, post treatment
  buffer and stage 1 anaerobic digester
• Stage 3 Existing Lagoon 1 taken offline for
  partition construction and aeration system
  installation. Use Stage 1 anaerobic digester to
  replicate existing biological process
• Stage 4 Stage 2 anaerobic digester

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COMMISSIONING SEQUENCING

• Storm flow buffer
• Clarifier, RAS/WAS, tertiary filter, chemical
  dosing systems, post treatment buffer
• Biological process
• Solids treatment systems
• 3 month commissioning period