Changyi Petrochemical did a recent analysis of its sulfur-bearing wastewater and purified water treatment rates of NH3-N, S2- reached 99.3～99.7 percent and 99.7～99.8 percent. The NH3-N content of the purified water was below 30 mg/l, and COD was down to 300 mg/l, putting them near the top in the industry. These meet Changyi’s environmental protection standards. As industrialization increases, water pollution affects development, so it is important that waste water be treated and Changyi Petrochemical has strengthened its environmental controls and increased spending on pollution controls to keep up with the times. It has pushed scientific and technological innovation, raised emission standards, and moved ahead in treatments, clean production, and a circular economy, and raised the technical index of sewage treatment. And its efforts have paid off, with emissions, especially COD and NH3 - N, effectively controlled. It had zero pollution accidents in recent years and delivered a good performance in pollution control.
It has kept tabs on wastewater discharges for some time and, with an expanding production scale, sulfur-containing wastewater treatment has become more important for its survival and development. It has spent more than 5.6 million yuan on its sour-water stripping unit and wastewater treatment A/O pool, and on installing a wastewater monitor. It has improved clean production, process control, and end treatment technologies to ensure wastewater discharge quality. Some of the sulfur-containing wastewater is recycled after stripping and some goes through end treatment with oil-containing wastewater before discharge. The company now has comprehensive utilization of solid waste and wastewater, as well as wastewater reuse, and the efficient use of water resources, reaching its economic growth and environmental control goal.