| Supplier Quality | Manufacturing quality system | Documented quality procedures; traceable inspection records; welding and pressure-test controls where applicable | Reduces fabrication defects, installation delays, and premature failures | Review valid certificates, inspection plans, material records, and factory acceptance test reports | 8% |
| Relevant project experience | At least 3 comparable installations using similar sludge characteristics and capacity | Reference projects provide evidence that stated performance can be achieved in practice | Request anonymized performance data, operating hours, feed solids, cake solids, and polymer consumption | 8% |
| Testing and commissioning support | Pilot testing or site-specific process validation before final selection | Sludge behavior varies significantly with origin, season, and chemical conditioning | Use representative sludge samples and define acceptance criteria in the contract | 7% |
| Spare parts and service capability | Critical spare-parts list; technical response within 24–48 hours; clear warranty terms | Downtime can cost more than the initial equipment price | Check local service arrangements, spare-part lead times, training scope, and warranty exclusions | 7% |
| Documentation and compliance | Complete manuals, electrical diagrams, safety instructions, and export documentation | Good documentation improves safe operation and future maintenance | Include documentation review in the technical bid evaluation | 5% |
| Equipment Performance | Feed sludge solids concentration | Typically about 0.5%–5% dry solids, depending on the sludge source and thickening process | The equipment must be sized for the actual feed condition rather than water-treatment averages | Confirm the design range using laboratory testing and historical plant data | 5% |
| Cake solids content | Common operating ranges: approximately 15%–25% for belt presses, 18%–30% for centrifuges, and 15%–30% for screw presses | Higher cake solids generally reduce hauling, storage, and disposal volumes | Require test results based on the same sludge type, polymer, and throughput as the proposed application | 12% |
| Hydraulic and solids throughput | Evaluate both m³/h and kg dry solids/h; design capacity should include reasonable operating margin | Hydraulic flow alone does not indicate actual dewatering capacity | Compare guaranteed capacity at the stated feed solids and cake-solids target | 10% |
| Polymer consumption | Often evaluated in kg polymer per tonne of dry solids; actual demand depends on sludge chemistry and polymer type | Polymer is a major recurring operating cost and directly affects cake quality | Use jar tests and pilot trials instead of relying only on catalogue values | 10% |
| Electrical energy demand | Compare kWh per tonne of dry solids, including ancillary equipment such as pumps, mixers, and polymer systems | Ancillary systems can materially change the actual energy profile | Request an itemized power schedule and verify it against the guaranteed operating point | 8% |
| Noise, odor, and wash-water demand | Confirm site-specific limits, enclosure requirements, cleaning frequency, and wash-water consumption | Environmental and utility requirements can affect layout and operating cost | Include these values in the technical offer and site acceptance test | 5% |
| Total Cost of Ownership | Initial equipment and auxiliary systems | Include dewatering unit, feed pump, polymer preparation, control panel, conveyors, enclosure, and commissioning | A low equipment price may exclude essential systems and installation items | Use a like-for-like commercial comparison with a complete scope-of-supply matrix | 8% |
| Installation, freight, and commissioning | Evaluate shipping, lifting, civil works, electrical installation, operator training, and start-up support | These costs can significantly increase delivered project cost | Request a separated quotation for each cost element and identify buyer-supplied items | 5% |
| Chemical and energy cost | Calculate annual cost from guaranteed polymer consumption, power demand, operating hours, and local utility prices | Recurring costs commonly exceed the initial purchase price over the equipment life | Use a five- to ten-year life-cycle cost model with clearly stated assumptions | 10% |
| Maintenance and replacement parts | Estimate routine service, wear components, lubrication, screens, belts, bearings, seals, and other consumables | Wear-part life and availability affect both cost and uptime | Request a preventive-maintenance schedule and a three-year spare-parts budget | 7% |
| Sludge disposal and transport | Calculate disposal cost from annual wet-cake mass, cake solids content, transport distance, and local gate fees | Improving cake dryness can reduce the quantity requiring transport and disposal | Run sensitivity analysis for different cake-solids results and disposal prices | 8% |
| Total Evaluation Weight | 100% |