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

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

Project Shotover: MLE Wastewater Treatment Plant

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

Project Shotover: Inlet Works Highest flow is from the Queenstown line (100-200l/s) Three other inflow lines

Project Shotover: Inlet Works

Project Shotover: Example of Site Flows

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

Project Shotover: Wastewater flows Highest flow from Queenstown 1 (100- 200l/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

Project Shotover: Modified Ludzack-Ettinger (MLE)

Project Shotover: MLE Plant Anoxic Zone in Foreground Aeration Zone

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.

Project Shotover: Modified Ludzack-Ettinger (MLE) Reactor

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

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

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

Project Shotover: Example Nutrient Results

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

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

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

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

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

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

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%

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

Project Shotover: Questions