Integral Residual Water Management

Refineria Balboa, in accordance with the strategies laid out in the Guide to BATs, will create a "Water Master Plan" who goal will be to minimise consumption by means of recycling and reuse.

The ultimate aim of reducing fresh water consumption, as well as that of treated waste, will be achieved by various actions:

• Design of an appropriate drainage system.
• Rainwater management.
• Reduction in equipment’s freshwater consumption
• Reuse where possible of used water (Integration).
• Sanitary water management
• Supply of fire fighting systems with recycled treated water of contrasting quality.
• Minimisation of purge water.

Sour water treatment

During the catalytic cracking and hydrocracking processes, whenever steam condenses in the presence of gases with variable quantities of hydrogen sulphide (H2S), streams containing sulphides, known as "sour water", are produced. Water containing sulphides and/or ammonia is treated by a removal (stripping) process with steam before being sent to the communal treatment plant. The aim of this process is to remove sulphides and ammonia from the water.

Simplified diagram of the sour water unit process

Source: Guide to BATs in the Oil Refinery Sector, Ministry for the Environment.

Residual water treatment

Residual water generated in the refinery is caused by: condensed steam, separation water, the discharge produced by refrigeration tower and boiler purges, wash water, water from the desalination of crude, water from the neutralisation of residual acids and alkalines, and water related to other processes, like sanitary water. These are all treated in the following way:

Water from the different sources mentioned is collected and kept in pools, from where its separation and distribution is controlled.

The residual water treatment process consists of four main stages:

1. Phase 1. Separation of hydrocarbons and solids in suspension.
2. Phase 2. Removal of emulsified hydrocarbons and very small suspended solids.
3. Phase 3. Removal of dissolved hydrocarbons, oxidisation of possible residual H2S and, if necessary, nitrification/denitrification.
4. Phase 4. This phase is used on water to be reused in the processes.

Residual water treatment process

Water disposal

Refineria Balboa’s end waste, always complying with Integrated Environmental Authority quality standards, will be discharged to a public waterway whose location will be authorised by the Guadiana Hydrographical Confederation.