Process water reuse - Reduce cost and environmental impact

Rising prices for freshwater let industries look out for ways to reduce cost for process water. One way to reduce cost for process water is water reuse also called water recycling.

To reuse or recycle process water from a cooling tower several steps for water treatment are required. Bar screens to remove debris that could cause damage in the following treatment steps. In the equalization tank process water is mixed and base or acid is dosed to change the PH value of the waste water. This is important because biological processes in the following steps require a PH value of 7. Afterwards in the lamella clarifier tank particles are removed via sedimentation. Gravity forces let the particles settle down.

By dosing flocculants into the waste water particles clump together to bigger particles and settle down faster. This process is called flocculation. By adding lamella clarifier modules aka tube settlers or plate settlers into the lamella clarifier tank the settling velocity of the particles is enhanced. In the next step BOD (biological oxygen demand) in the form of organic waste is removed in the aeration tank. Microbes decompose the BOD into smaller particles which are settled down in the basin as sludge.

This sludge is recycled to the lamella clarifier tank where it is aged before it is send back to the aeration tank as food for the Microbes. To improve the aeration process and BOD removal FBBR (fixed bed biofilm reactors) as provided by AET can be added into the aeration tank. In a final step the process water is polished and disinfected in a activated carbon filter.

The activated carbon filter removes the last remaining fine particles before the water can be reused for the cooling tower process. Reuse of process water is becoming more and more important because it reaps monetary benefits but also reduces environmental impact. The lamella clarifier technology aka tube settlers and FBBR (fixed bed biofilm reactors) from AET improve this process and lead to further cost reduction.

SOURCE

Attached link

Media

Taxonomy

• Cooling Systems
• Produced Water
• Cooling Systems
• Moving Bed Biofilm Reactor (MBBR)
• Utility Boiler and Cooling Water Treatment