Presentation on theme: "Commercial Application of an innovative membrane bioreactor for waste water treatment at Glanbia Ingredients Ltd. Ballyragget Site Presented by: Karen."— Presentation transcript:
Glanbia was faced with two major challenges following the issue of our IPC Licence in December 1998. i.Following the merger of the Avonmore Foods Plc. and Waterford Foods Plc. to form Glanbia Group, it was decided to close the Dungarvan site and process up to 60% additional milk and whey on the Ballyragget site. At the same time, the emission limit values in the new IPCL were being reduced. ii.The type of emission values outlined in this license could not be delivered by conventional technology. Glanbia carried out research on what technology was available in the latter half of 1998 with the objective of upgrading its waste water treatment plant for the 1999 peak season. Development of the New Process Technology
OPTIONS CONSIDERED FOR PLANT EXPANSION Remain with proven conventionaly technology Extend existing biotower, increase clarification capacity Or deviate from the norm and rewrite the rules of water treatment.
Waste Water Treatment Inputs Milk per annum-201M gallons Whey per annum-203M gallons Outputs520 million Gallons Wastewater To Be Treated 490 million Gallons Treated Permeate To River Nore 3.5 million gallons of Sludge
Disposal Costs/annum£464,000 Landbank Maintenance Costs/annum £54,000 Total Costs£518,000 Income from Pig farmers/annum £100,000 Waste Minimisation: Delactosed Permeate
800-850m3/day Diverted from effluent to Cooling Line <50mg/l COD Rennet Casein RO2 UF2 LactoseWPC Acid Whey Acid Whey Wash Water UO UF3 RO1 Gemini PR 100m3/day Off Site Treatment P R P P Waste Minimisation: Whey Gemini Plant
100m3/hr 5 Evaporators Recycled as Boiler Feed Make Up Water Recover & use as pre-rinse for membrane CIP PreRinse in Whey CIP’s, evaps, tanks, silos etc. General Cleaning RO Polisher Retentate to Effluent Waste Minimisation: 2 nd Stage Condensate Polishing
OPTION CHOSEN To expand treatment capacity from 15,000Kgs COD to 30,000kgs/Day, 2 limiting factors: Oxygen Transfer in aeration basin And the inability of settlement in final clarifiers at MLSS above 2,000. Solution – Suprafilt fine bubble air diffusers and Kubota membranes. Operating now at 8,000 mg/l MLSS in the oxidation ditch
BOD Reduction BOD IN 20,000kg/day Conventional Technology 98.6% Kubota Technology 99.5% WWTP BOD OUT
Principle of Operation Screened Effluent ex oxidation Ditch Air in In Waste Sludge (to further treatment) Treated & disinfected effluent Out
The Kubota membrane bioreactor is essentially a high MLSS activated sludge process where the Kubota membrane treatment units are submerged within the extended activated sludge tanks. Typically, the activated sludge is maintained in the range 15 – 20,000 mg/l MLSS. Specific Innovative Elements
In operation, the treated effluent through the membrane units is controlled by available gravity head (typically 1 – 1.5 metres). The number of units installed is dependant on the maximum flow rate required. The plant at Ballyragget comprises 74 packs for a guarantee flow rate of 7,300 m 3 per day. However, it is hoped that flow rates of 9,000 3 per day will be achieved.
WWTP Flow Denitrification tank Existing Oxidation ditch (13000 m 3 ) Preliminary treatment: - Screen - DAF - Biofilters Existing settlement tanks Outfall to river Feed 7-9000 m 3 /d Recycle/return sludge Future capacity Re-use 16 t/d BOD Kubota membrane units
Energy Requirements for new plant Upgrading and Expansion of the Treatment plant cost IR£3 Million, with the Kubota membranes costing IR£1.6 Million and the installation of a new aeration system, Suprafilt Fine bubble diffusers. Aerzen fine bubble diffusers – 50-60% increase in Oxygen Transfer when compared with surface rotors. Energy usage. Conventional plant would not achieve the 10:15, BOD:SS standard
Operational Difficulties Encountered 150% Of design airflow was required to maintain flux. No Standby blower. Membrane scaling incidents. Membrane sliming. Sludging between membrane plates, reduces flux. Wear on plates.