大连石化污水气浮工艺存在的问题与对策

Problems of Sewage Dissolved Air Flotation Technology Used by Dalian Petrochemical and Solutions

大连石化公司污水处理场一期工程溶气气浮单元,在运行过程中多次因设备故障和超标排水等原因导致运行效果不佳。实际运行经验表明:当溶气释放水中产生大气泡,在池面形成翻花时,可通过提高溶气罐液位,降低压缩空气量来解决;污水量增大时可通过降低调节池出水量,提高溶气回流水量,增加混凝剂、絮凝剂投加量来解决;压缩空气量过小时,可通过关小回流泵出口阀门,调节空压机阀门开度来解决;溶气罐液位急速下降可通过关闭空压机入口阀,打开溶气罐液位放空阀泄压来解决;溶气罐压力下降可通过关闭空压机进入溶气罐入口阀,待压力正常后再缓慢开阀来解决;出水水质超标时,可通过增加混凝剂、絮凝剂投加量,调整气浮单元的溶气量和回流量来解决。通过以上方法,溶气气浮系统可以在非正常工况条件下达到出水水质合格,保证后续处理的连贯性。

The performance of the dissolved air flotation unit of Phase I of PetroChina Dalian Petrochemical Company＇s sewage treatment plant has long been unsatisfactory due to a combination of factors such as e- quipment failure and off-spec sewage discharge.The operation of the unit shows that：when dissolved air re- leased into water produces large air bubbles and generates water splashes at the surface of the pond,the problem can be resolved by raising the level of liquid in the dissolved air tank to reduce the volume of compressed air; when the volume of sewage increases, the problem can be resolved by reducing the volume of water discharged from the regulating reservoir,raising the volume of refluxed dissolved air water and increas- ing the use of coagulating agents and flocculating agents;when the volume of compressed air is excessively low,the problem can be resolved by reducing the opening of the valve of the outlet of the reflux pump and adjusting the opening of the valve of the air compressor;When the level of liquid in the dissolved air tank drops sharply, the problem can be resolved by closing the valve of the inlet of the air compressor and open- ing the level venting valve of the dissolved air tank ;when the pressure of the dissolved air tank drops ,the problem can be-resolved by closing the valve of the inlet where air enters the dissolved air tank from the air compressor and gradually opening the valve when the pressure returns to normalcy;when the water dis- charged is off specifications,the problem can be resolved by increasing the use of coagulating agents and flocculating agents and adjusting the volume of dissolved air and reflux of the air flotation unit.Using the above measures ,the dissolved air flotation system can discharge water meeting-quality standards under abnormal working conditions to ensure the consistency of subsequent treatments.