1. Modified Ludzack-Ettinger Wastewater Plant
Project Shotover
Modified Ludzack-Ettinger Wastewater Plant

2. Modified Ludzack-Ettinger (MLE) Wastewater Treatment Plant.
Project Shotover
Modified Ludzack-Ettinger (MLE) Wastewater Treatment Plant.

3. Project Shotover: MLE Wastewater Treatment Plant

4. Project Shotover: Introduction
Population increase in Queenstown
Discharge effluent BOD, Total Suspended Solids, Ammonical Nitrogen and Total Nitrogen limits decreased in new consent.

5. Project Shotover: Inlet Works
Highest flow is from the Queenstown line ( l/s)
Three other inflow lines

6. Project Shotover: Inlet Works

7. Project Shotover: Example of Site Flows

8. Project Shotover: Septage
Septage truck drivers swipe their card which identifies them and the volume received is recorded.
100m3 tank
Rock trap, macerator, pump and flow meter
Septage is pumped to the inlet works

9. Project Shotover: Wastewater flows
Highest flow from Queenstown 1 ( l/s)
Flow split is approximately 63% to MLE and 37% of flow to the ponds
80% of water used onsite is recycled process water from the clarifier filtered and UV treated

10. Project Shotover: Modified Ludzack-Ettinger (MLE)

11. Project Shotover: MLE Plant
Anoxic Zone in Foreground
Aeration Zone

12. Project Shotover: MLE
Influent Wastewater has grit removal, is screened and pumped to the inlet of MLE.
Two recycle streams- RAS Return activated sludge from the clarifier and the A- recycle- recycled mixed liquor from aerobic zone
Mixed liquor from the aerobic zone 2 flows to the clarifier and then to the UV before Discharge.

13. Project Shotover: Modified Ludzack-Ettinger (MLE) Reactor

14. Project Shotover: MLE
Influent, A-recycle and Recycled Activated Sludge RAS into Pre- anoxic zone
Aerobic zones 1 and 2 – Nitrification
A-recycle mixed liquor suspended solids from aerobic zones to anoxic zone for Denitrification

15. Project Shotover: Nitrification and Denitrification
Anoxic Zone in Foreground Dddd Denitrification
Aeration Zone Nitrification

16. Project Shotover: MLE Plant
Denitrification: Anoxic Zone
NH3+NH4+ Ammonical N NO3- Nitrate-N
Nitrification: Aeration Zone
NO3- Nitrate-N N2 Nitrogen gas + N2O Nitrous oxide

17. Project Shotover: Example Nutrient Results

18. Project Shotover: Aeration
Fine bubble diffused aeration diffusers for swing(when operating as aerated) and aerobic zones 1 and 2.
Dissolved Oxygen meters in each zone feedback to modulate blower speed and control valves

19. Project Shotover: Aeration
Dissolved Oxygen Targets in MLE
Anoxic zone <0.5ppm
Swing zone =2ppm (when aerated)
Aerobic zones =2ppm

20. Project Shotover: Clarifier
34m diameter, 4.5m deep
Removal of sludge via perforated sludge collection pipe vacuum rotation
Floating solids collected by surface scraper rotational bridge and removed to scum tank

21. Project Shotover: Clarifier
Recycled Activated Sludge RAS stream removed from clarifier base and pumped to pre-anoxic zone
RAS flow rate is typically 0.8-1x MLE influent flow rate

22. Project Shotover: Waste Activated Sludge
Waste Activated Sludge (WAS) is removed from the MLE and dewatered
The target solids % from the centrifuges is 20% and 95% capture
Cake and centrate are affected by factors including; WAS solids %, polymer type, concentration and dose point, centrifuge solids loading and settings

23. Project Shotover: Decanters
Two GEA decanters for dewatering Waste Activated Sludge (WAS)
Target sludge solid content >20% solids, recovery >95%

24. Project Shotover: UV and Discharge
Pond and MLE effluent blended before UV treatment approximately 63% MLE: 37% Pond Effluent
7 bank UV, 11 lamps
UVT generally around 51%

25. Project Shotover: Biological Commissioning
Seed sludge not used, sludge MLSS was built from influent wastewater and recycle
Increased Christmas and New Year load assisted with building MLE biomass

26. Project Shotover: Questions