Dewatering energy per dry tonne can reveal a trade-off that a polymer-only comparison misses. A candidate might improve drainage enough to change operating time, or it might require conditions that increase electrical demand. To evaluate that fairly, define which equipment is metered and calculate the dry-solids throughput over the same period. A lower instantaneous kilowatt reading is not automatically lower energy per tonne.
Draw the electrical boundary
List the machine drive, feed pumps, preparation equipment, wash systems and auxiliaries included in the measurement. Use an appropriate metering arrangement installed or accessed by authorised personnel. Do not compare a whole-building electricity total with a single-machine figure and describe the difference as chemical savings.
State whether startup, idle and cleaning energy are included. Both a steady-operation comparison and a complete-shift comparison can be useful, but they answer different questions. Keep their boundaries visible in the report instead of combining whichever values make a candidate look favourable.
Align energy with dry solids processed
Energy consumption in kilowatt-hours divided by dry tonnes processed gives the specific-energy figure for the defined period. For illustration, 300 kWh used to process 10 dry tonnes equals 30 kWh per dry tonne. This is arithmetic, not an expected equipment benchmark. The result is only as reliable as the energy reading and the sludge flow and solids measurements.
When discussing trials with Xinqi Polymer or another polymer manufacturer, provide the calculation boundary and throughput record. The site's industrial trial articles explain why preparation and sampling conditions also belong in the comparison.
Retain cake quality and capture constraints
A machine can appear electrically efficient if it processes sludge rapidly while losing more solids to centrate or filtrate. Likewise, a wetter cake may reduce one machine's demand but increase transport or downstream handling. Hold the agreed quality and capture requirements in view; specific energy is one decision variable rather than a replacement for the treatment objective.
Record mechanical settings and changes in sludge blend. If several variables moved during the comparison, qualify the attribution rather than assigning the whole energy difference to polymer chemistry. Repeat across representative conditions when the apparent saving is small relative to normal variation.
Convert to cost without overstating precision
Use the tariff basis relevant to the comparison and explain any charges not captured by a simple energy price. Add polymer consumption and the measured handling consequences using compatible periods. Report uncertainties and distinguish observed trial results from annual projections. The procurement outcome should be a defensible whole-process comparison, not an annual saving extrapolated from a brief, unusually favourable meter reading.