Upstream Investment Equals Downstream Saving By Alex Lloyd Managing Director – Jacopa Ltd
Overview ‘The seismic shift towards Totex is putting the onus on delivering outcomes rather than outputs.’ We will argue, using grit as an example, that spending more at the preliminary stages of treatment will lower the overall Totex for the whole treatment system. P-25 Grit Clasifier Primary Settlement Humus / Final Settlement Screenings Compactor Settled Effluent Grit Screenings FE Final Effluent Raw Partially treated Sewage Returns Biological Treatment Incoming Sewer Screened Sewage Raw Sewage Crude Screens Storm Return Storm Water Reception Gas Gas for Power Storm Sump Recycle pump Secondary Generation Return Sludge Pump Grit Trap Pumps Storm Tanks Primary Sludge Waste Digested Sludge Primary Sludge Pump Digester
Totex – System Cost Impact ▪ Product suppliers historically look at cost of Ownership ownership for their product Cost of • E.g. Pump Capex and efficiency for given duty ▪ Suppliers need to ask ‘what else impacts our products?’ ▪ Difference between Totex and cost of ownership Asset Ownership Cost System Totex Capital costs Capital costs System Impact Efficiency / power costs to use Power costs Maintenance costs (spares & time) Maintenance costs (spares & time) Operational staff costs Income from sale of products (power to grid) Risk of consent failures (fines and bad PR) Ongoing monitoring costs Innovation cost benefit
Outcomes – Industry Challenges “Outcomes must reflect what customers need, want and are willing to pay for” ▪ Re-use of existing assets in new configurations ▪ Maintenance of existing equipment ▪ Improved performance (e.g. pump efficiency) ▪ Longer life of assets with flexibility to upgrade and refurbish ▪ Reduced risk of service failure ▪ Compliance with environmental and drinking water standards ▪ Reduction in carbon emissions
Factors Impacting Totex & Outcomes Common theme! • Failure of Preliminary Treatment What happens upstream impacts on life and • Maintenance Concerns • Condition Monitoring operation of pumps and other equipment P-25 Grit Clasifier Primary Settlement Humus / Final Settlement Screenings Compactor Settled Effluent Grit Screenings FE Final Effluent Raw Partially treated Sewage Returns Biological Treatment Incoming Sewer Screened Sewage Raw Sewage Crude Screens Storm Return Storm Water Reception Gas Gas for Power Storm Sump Recycle pump Secondary Generation Return Grit Trap Sludge Pump Pumps Storm Tanks Primary Sludge Waste Digested Sludge Typical Flow Diagram Primary Sludge Pump • Failure of Preliminary & Primary Digester Treatment • Failure of Storm Treatment • Maintenance Concerns • Failure of Preliminary, Primary & • Condition Monitoring (preliminary treatment can be Biological Treatment used for storm treatment) • Maintenance Concerns • Maintenance Concerns • Condition Monitoring • Condition Monitoring • Failure of Preliminary Treatment • Maintenance Concerns • Condition Monitoring
What is Grit? Grit Removal is defined by WIMES as >200µm equivalent diameter (95% removal) Specific gravity 2.65kg/l Inorganic (sand, gravel, cinders, rock salt, egg shell) Also includes organics (coffee grinds, sweetcorn and seeds) THICKNESS OF A 20p PIECE
Why Remove Grit ▪ Grit is highly abrasive and ▪ Why remove grit >200µm? destructive • To comply with WIMES • In the network • Prevent further maintenance • costs downstream. To mechanical equipment Does grit less than 200µm present any operational concerns?
Pump and System Performance ▪ Increased Power • Removes efficiency coatings by abrasion • Increased friction in pipework • Settlement in pipework (reduced pipe area) ▪ Increased Maintenance • Blockage in pipes • Abrasion of pump castings, seals and bearings • Erosion of pipe material (too high velocity) • Difficult identification and access to problem ▪ Departure from design parameters (e.g. pump system curves, digester throughput) ▪ Reduced life and early component replacement
How Does Grit Impact Totex? P-25 Screenings Grit Clasifier Primary Settlement Humus / Final Settlement Compactor Settled Effluent Grit Screenings FE Final Effluent Raw Partially treated Sewage Returns Biological Treatment Incoming Sewer Screened Sewage Raw Sewage Crude Screens Storm Return Storm Water Reception Gas Gas for Power Storm Recycle pump Secondary Sump Generation Return Sludge Pump Grit Trap Pumps Storm Tanks Primary Sludge Waste Digested Sludge Primary Sludge Pump Digester ▪ Screens – damage from wear and ▪ Primary Settlement – Excessive tear (early maintenance) scraper wear (inefficient desludging) ▪ Compactor – abrasion of any screw (early maintenance) ▪ Biological Treatment – Fouling of ▪ Storm System – reduced life of aeration diffusers (increased power storm return pumps, increased consumption) cleaning and odour ▪ Digester – reduced volume and ▪ Interstage Pumps – abrasion on increased digging out (reduced impellor (inefficient pumping / yield & increased maintenance. increased power)
Examples of Downstream Grit Deposition Detritor (not maintained) Dug out of digester Digester reduced volume Aeration Lane (diffusers fouled) Pump wear Quantity and size of grit coming from Pipe failure the catchment is unknown (depends on individual catchment)
Removing Grit Rake Transfer ▪ Separation is done at settlement Cross Flow velocity. Recessed Impeller ▪ Transfer is done using equipment designed for grit Classifier Cleaning ▪ Cleaning removes Ram Pump the organics and Vortex prevents odour ▪ Opex must include Maintenance Grit Channel ▪ Air Lift Totex impact on system cost Separation
Operating and Maintenance Considerations ▪ Regular and efficient removal from settlement zone ▪ Inspection of equipment for correct operation • Wear strips checked and replaced • Scrapers operating effectively • Reciprocating rakes linkage operational • Realignment / replacement of mechanical assemblies ▪ Greasing and other regular activities completed ▪ Cleaning off FOG (attracts grit forming a floating abrasive mixture) ▪ Address screen failures immediately ▪ Speak to the specialists
Upstream Investment vs Downstream Saving ▪ Totex is related to the complete system not an individual product • Upstream process units affect the performance of System Totex downstream equipment • Include any investment (time, resources and capital) • Re-use, re-configure, maintain or refurbishment of assets may be a more cost effect solution ▪ Building new assets means maintaining new assets; a greater Totex Grit Capex ▪ Improved upstream treatment equates to an Grit Opex improved downstream life of pumps and equipment Investment in Grit Removal ‘Suppliers need to engage with end users and each other, working together to deliver a lower Totex solution to meet an Outcome and not just their own product in isolation.’ Thank You
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