Imagination at work. Preserving the Environment by minimizing nutrient discharge and reusing high quality WWTP effluent Presenting author: Gabriel Kicsi, M.Eng. APAC UF/MBR RO-ED Domain Leader, GE Water & Process Technologies, Australia Coauthors: Mark Vis & Anna Whelan, Townsville City Council, Australia Chris Harpham, GE Water & Process Technologies, Australia 8 th Pacific Water & Wastewater Conference Holiday Inn, Port Moresby, Papua New Guinea 14 th -17 th September 2015

2 / Connelly / Background: Preserving the Environment Cleveland Bay Purification Plant Townsville, QLD, Australia Stringent discharge requirement to limit impact on Great Barrier Reef Marine Park High Quality treated effluent available for reuse 5 yrs severe drought MBR upgrade-membrane tanks in center of retrofit clarifiers 29MLD ADWF (7.6 MGD ) 75MLD PWWF (19.8 MGD ) Challenge: Minimize nutrient discharge to sensitive water body (Great Barrier Reef) Solution:Complete wastewater treatment and reuse system

3 / Connelly / Background: Max. Reuse of Existing Infrastructure 1.Hydraulic & Structural Refurbishments: Existing Primary Screening & Aerated Grit Removal 2.Conversion of existing flat floor Secondary Clarifier No1 into a sloping floor Primary ST 3.Conversion of existing Secondary Clarifier No2&3 into hydraulically linked but separate MBR (BNR OxDitch + MT) 4.Prefabricated SS Membrane Tanks and Pipework reduced fabrication & erection time 5.Reuse of existing sludge thickening and digester’s Challenge: Minimize construction time & ensure quality effluent during constr. Solution: Stage-wise implementation of retrofitting 2 existing secondary clarifier

4 / Connelly / Key Reasons for MBR Selection MBR effluent quality is consistently better than conventional treatment: Filtration requirements for reuse applications and/or feed to downstream process Compact footprint: Hollow Fibre vs Flat Sheet Heated civil construction market Most cost effective solution to produce feed water to the proposed irrigation and potential industrial Water reuse scheme Membrane Technology advances and membrane cost reductions

5 / Connelly / Design Basis of the Upgrade Capacity: Community served:126,000 EP Average dry weather flow (ADWF):29,000 m 3 /d Peak Wet Weather flow MBR:75,000 m 3 /d Peak Wet Weather flow (PWWF):145,000 m 3 /d Average Loads (t/d) COD14.5 SS 5.7 TKN 1.45 Phosphorus (P tot ) 0.23

6 / Connelly / Conventional activated sludge (1988) with: Primary screens Aerated Grit tanks Extended aeration – oxidation ditch Secondary clarifiers Waste sludge Treatment Stage 1 (1994) with DAF Thickener Anaerobic sludge digestion: 2 Primary + 1 Secondary Digesters Sludge Drying Lagoons Existing Plant – Unit Operations

7 / Connelly / Existing Plant Unit Operations & Upgrade Design

8 / Connelly / Upgraded CBPP – Aerial Photograph

9 / Connelly / Primary screens (3mm): 2 immersed Trommel Screens 2 Aerated Grit tanks with a single hydrocyclone for grit dewatering 1 Primary Sedimentation Tank converted from a previous Secondary clarifier Secondary Fine Screening (1mm): 4 rotary Huber screens 2 parallel, mirror imaged MBRs each comprising:  Anaerobic reactor (subdivided into 3 cells in series)  Denitrification/Nitrification (Oxidation Ditch –OxD-) with scum harvester  4 Membrane Trains (MT) with 6 ZW500d48/48 cassettes 2 Rotary screw thickeners for primary sludge thickening Single Dissolved Air Flotation (DAF) Thickener for WAS (extracted from MT) Anaerobic sludge digestion: 2 heated and mixed Primary + 1 pump mixed Secondary Digesters 2 Centrifuges for digested sludge dewatering (lime dosing) Sludge storage: concrete apron, partly roofed before trucking to pastoral land application Upgraded Plant – Unit Operations

10 / Connelly / Chemical Dosing Systems comprising :  Ethanol Dosing: to OxD for supplementary N removal  Alum Dosing: to MBRs for supplementary P removal  Polymer dosing: to sludge thickeners (rotary screw & DAF) and centrifuge  NaOCL & Citric acid for membrane MC & RC  Caustic (when req.) when odour control is off line & during maintenance Odour Control with 3 single pass BTFs of:  Inlet screens (both primary & secondary),  Raw sewerage channel  Primary sedimentation tank (PST launders),  Primary effluent & outfall pump station  Primary Sludge Thickeners/ RST & WAS Treated Effluent discharged either to upgraded ocean outfall or storage Tank for reuse Upgraded Plant – Unit Operations (Cont’d)

11 / Connelly / CBPP Process Flow Schematic Raw Wastewater Treated water to WRF or Ocean outfall Sludge for disposal Primary screenGrit removal Fine screens Anoxi c AerobicMembranes Anaerobic Sludge Digestion Centrifuge Anaerobic Primary ST SQ-4 RQ-1 AQ DAF WAS To Inlet structure Rotary Screw Thickener

12 / Connelly / CBPP – Site Plan Head Works Digester s Fine Screens Perm. Pump Pit MBR 2 MBR 1 Distribution Chamber PS T Blowers + MCC

13 / Connelly / CBPP – Unit Operations (Cont’d)

14 / Connelly / CBPP – Unit Operations (Cont’d)

15 / Connelly / CBPP – Process Equipment Permeate Pumps during Installation

16 / Connelly / CBPP – Process Equipment 2 R-Recycle Pumps 4 S-Recycle Pumps 2 WAS Pumps 2 A-Recycle mixers

17 / Connelly / CBPP – converted clarifier into BNR MBR

18 / Connelly / CB WWTF – Membrane Installation Chemical dosing and Sludge Storage

19 / Connelly / CBPP MBR Design Notes MT MLSS concentration: 9-12 g/l (maximum of 15 mg/l) Membrane Cleaning Strategies: –Air Scouring: 10/10 for PWWF and 10/30 for ADWF –Relaxation/Backpulse selectable options –Maintenance cleans: weekly NaOCl and Citric acid cleans - 1x/month in dry season and 1x/every 2 wks in wet season –Recovery Cleans: 2x/year (before and after wet season) MBR Control: Permeate pumps trimmed based on OxD level

20 / Connelly / CBPP - Operating Performance

21 / Connelly / CBPP - Operating Performance

22 / Connelly / CBPP - Operating Performance

23 / Connelly / CBPP - Operating Performance

24 / Connelly / CBPP - Operating Performance

25 / Connelly / CBPP - Operating Performance

26 / Connelly / CBPP - Operating Performance

27 / Connelly / CBPP - Operating Performance

28 / Connelly / CBPP - Operating Performance

29 / Connelly / CBPP - Operating Performance

30 / Connelly / CBPP - Operating Performance

31 / Connelly / CBPP - Operating Performance

32 / Connelly / CBPP - Operating Performance

33 / Connelly / Summary - Conclusions MBR technology offered a smaller footprint, by integrating membranes and BNR processes within existing WWTP infrastructure Retrofitting existing structures reduced on-site construction which in turn reduced erection time and overall project cost (Total cost: $ 65M AUD) The long term, 7+ years, average of 8 trains membrane permeability ranged between 350 and 150 Lmh/bar, respectively. The main plant specific power consumption varied between 0.46 and 1.03 kWh/ m 3, which is well in line with the reported values MBR + BNR minimised nutrient load to Great Barrier Reef Marine Park (61 ton nutrients – 56 ton TNand 5 ton TP - per annum on 90%ile basis Nutrient Recycled to land and high quality effluent available for reuse the achieved median and 52 weeks 90%-ile faecal coliform values of the treated composite effluent were < 2 CFU/100mL and 17.7 CFU/100mL, respectively