At the biochemical wastewater treatment workshop of the utility plant operated by Shanxi Coking Co.,Ltd. (SH: 600740), process deputy director Yan Wenhong points to the foam in the aeration tank, explaining that any shift in foam thickness or bubble size signals changing microbial activity, serving as an early warning for water quality control. Relying on this foam observation technique, the plant has managed to nip water quality fluctuations in the bud.
Previously, COD and ammonia nitrogen levels exceeding standards in the effluent from three biochemical treatment units had been a persistent challenge. During this year's Quality Month, the plant rolled out a series of targeted corrective measures: adjusting sludge return and increasing nitrification liquid回流 in response to any indicator fluctuation; intensifying detection frequency for dissolved oxygen, pH, and alkalinity in the aeration tank from once every two hours to hourly; regulating blower air volume as needed while maintaining alkalinity steadily above 400 mg/L, with soda ash added when necessary to ensure stable nitrification reactions.
Building on these steps, frontline operators have stepped up patrols, judging microbial status by observing foam conditions and responding promptly to anomalies. In cases of severe indicator fluctuations, activated sludge is added and the aeration tank undergoes闷曝 to quickly stabilize the system; sodium hypochlorite is dosed into the third biochemical contact oxidation tank to enhance COD and ammonia nitrogen removal; and sodium bisulfite addition is increased to tightly control the ORP of reverse osmosis influent.
Through this combination of measures, the utility plant has further stabilized equipment performance and elevated water quality. Yan Wenhong notes that indicators are surface-level while the system is the root cause, emphasizing that front-end regulation, mid-stream emergency response, and back-end protection each require rigorous attention, which naturally ensures stable water quality. Currently, COD in the effluent from the three biochemical units has dropped from above 120 mg/L to a steady level of around 110 mg/L, with ammonia nitrogen reduced to below 5 mg/L, meeting control requirements.
Author: Liu Yayu | Editor: Liang Ruihua | Duty Editor: Gao Huiqin
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