Process Optimization & Control
A²/O Process Instrument Replacement at Hangzhou Qige WWTP
1 / 2Project Background
A²/O process instrument replacement at a 1.2 million t/day plant.
Customer Challenge
This 1.2 million tons/day A²/O plant must meet national Class 1B. Built with imported instruments, procurement and O&M costs were high. Large biological processes depend strongly on suspended-solids, DO, pH and ORP monitoring, so reliable process instruments were needed to replace imports with domestic equivalents.
The TENGINE Solution
MLSS suspended-solids meter, LDO optical dissolved oxygen meter, pH meter, ORP meter.
Implementation
MLSS Suspended Solids (Sludge) Concentration Analyzer, LDO Luminescent Dissolved Oxygen Analyzer, TPH pH Analyzer, TORP ORP Analyzer.
Project Results
Import substitution at a super-large municipal plant cut procurement and O&M costs. Instruments have run stably for nearly five and a half years, proving domestic reliability at a million-ton scale and keeping 1.2 million tons/day at Class 1B — a practical reference for domestic instrument upgrades.
Related Case Studies
The plant handles a large daily flow through a complex multi-stage process, requiring precise control of influent/effluent quality and process status. Water quality data must also feed the environmental regulator's system, but legacy single-parameter instruments with lagging data could not support full-process control or compliant reporting.
Municipal wastewater plants present complex conditions and fluctuating water quality. Instruments run continuously while submerged, so conventional meters age, drift and fail — driving up replacement and maintenance costs and conflicting with the need for long-term, low-maintenance operation.
Aging online instruments no longer met current pollution-source monitoring specifications. The project had a tight schedule and complex construction, requiring on-time delivery of a large instrument batch; multiple dispersed sites demanded certified, stable devices connected to a smart-water platform, plus complete installation and commissioning services.
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