Basildon AMTREAT LTP Commissioning of a high-rate ammonia removal plant. Oscar Hernandez-Ramirez Sarah Collins Steve Bungay

Transcription

1 Basildon AMTREAT LTP Commissioning of a high-rate ammonia removal plant Oscar Hernandez-Ramirez Sarah Collins Steve Bungay

2 Introduction ACWA AMTREAT process review Basildon STW site overview Set-up and commissioning strategy Commissioning results Conclusions and further work

3 The AMTREAT Process - History The ACWA AMTREAT Process is a high-rate activated sludge plant for treating high-strength ammonia liquors no. Water Companies invested in research to treat high-strength digested sludge liquors Pilot-plants located at Manor Farm and Wargrave WwTWs st full-scale plant installed for treatment of sludge liquors nd full-scale plant becomes operational new plants under construction

4 The AMTREAT Process History (cont.) First generation (Cliff Quay) Nitrification only Cold liquors; heating required (25 o C op. temp.) Second generation (Ashford) Anoxic zone incorporated Partial denitrification Third generation (Basildon, Colchester, Cliff Quay upgrade) Glycerol dosing for full denitrification Heat exchanger (cooling) incorporated Fourth generation (Worksop) Dual tank arrangement (anoxic within aerobic) Currently under construction

5 AMTREAT Process Full nitrification and denitrification using conventional pathways no short-circuiting Robust and flexible process can take a wide variation in flows and loads AMTREAT is not dependent on critical operational balance between SRT and HRT; influent ammonia concentration; dissolved oxygen concentration; and reactor temperature High biomass concentration provides improved removal of hard COD, and improved tolerance to ammonia or COD toxicity Can be retrofitted into / using existing assets Simple to operate and control

6 Anglian Water AMTREAT LTPs 3 No. Amtreat LTP - Colchester new build - Basildon new plant using existing assets and new build - Cliff Quay upgrade of existing plant using existing assets and new build Designed for full nitrification and denitrification Sodium hydroxide dosing into AMTREAT reactor for supplemental alkalinity ph linked Glycerol dosing into the anoxic tank for supplemental carbon source for denitrification flow proportional Cooling heat exchanger on RAS return line

7 Anglian Water AMTREAT LTPs Average Design Flows and Loads Parameter kg/d Colchester Basildon Cliff Quay Flow (m 3 /day) TSS BOD Ammonia Alkalinity Temp ( o C)

8 Basildon AMTREAT LTP Turn-key project Design, Build, Testing, & Commissioning Configured for total nitrification Influent Anoxic Tank existing concrete tank AMTREAT Reactor existing concrete tank Stilling Tube Final Settlement Tank Process cooling HEX Sodium hydroxide dosing for supplemental alkalinity Glycerol dosing for denitrification and alkalinity recovery RAS / SAS pumps; internal recycle pumps Ammonia removal >90%

9 Basildon Amtreat LTP Schematic

10 Basildon AMTREAT LTP

11 Original concrete structure

12 Site under construction

13 Air pattern test

14 AMTREAT LTP area within Basildon STW

15 Basildon AMTREAT LTP FST Amtreat Reactors Blowers Anoxic Tank MCC Glycerol Dosing NaOH Dosing

16 Commissioning Plan Seeded with sludge from Basildon s municipal ASP Conventional nitrifying sludge Around 50% of the total aeration volume Flows and loads ramped-up as smoothly as upstream operations allowed Alkalinity/carbon dosing incorporated when/as required Operational parameters closely monitored Influent/effluent composition (NH 3, COD, BOD, TSS, TP, alkalinity) Temperature, ph MLSS, RAS/SAS rates SSVI Microscopy

17 Microscopy seed sludge

18 Microscopy AMTREAT biomass

19 Settlement SSVI below 80mL/g

20 Denitrification Average denitrification rate: 74%

21 Temperature control Feed liquors at >25 o C AMTREAT is an exothermic process Cooling system applied for the first time Optimum process temperature: 32 o C Temperatures successfully maintained between o C

22 Ammonia removal across commissioning

23 Evolution of ammonia removal rates Daily Flow m 3 /d Ammonia removal %age

24 Impact of feed variations Flow variation Daily %age Ammonia removal %age

25 Average chemical consumption Sodium Hydroxide Glycerol Daily rate (m 3 /d) Design figure (m 3 /d) Sodium hydroxide consumption within design predictions Glycerol dosing rate will be optimised as soon as the feed composition and flows are reliable Further alkalinity recovery expected Stable ph maintained throughout the system

26 Conclusions The AMTREAT LTP was successfully seeded with conventional ASP sludge, readily available on site Irrespective of the variability of the feed, the AMTREAT process reliably produces a high-quality effluent The biology was not disturbed throughout the commissioning period Temperature effectively controlled This third generation plant is designed to maximise nitrification, with glycerol and sodium hydroxide dosing to optimise denitrification and alkalinity recovery

27 Further work Glycerol dosing control should be fine-tuned by developing user-friendly control equations MLSS recycle to be optimised Dual tank arrangement (anoxic zone within aerated reactor)

28 Thank you