The destination of sewage is the Central Sewage Treatment Plant (CST). The Vistula is the receiver of purified sewage. It is discharged via four sewage systems leading to the CST area. The industrial sewage system (I) is characterised by a large amount of oil products and suspended solids. Sewage from the 1st industrial sewage system is treated mechanically and biologically (II° of biological treatment). In emergency cases, when pollutant concentration in sewage exceeds admissible values, such sewage may be directed to I° biological treatment devices to have its quality improved. This depends on sewage quality measurements at check points. Sewage is monitored. The industrial sewage system (II) also covers sewage which, apart from suspended soils and oil products, contains water soluble chemicals. Sewage from the 2nd system is treated mechanically and biologically.
Storm, drainage and post-cooling water from all refinery and petrochemical units is discharged to the refinery and petrochemical storm sewage system.
Storm water from the refinery part is contaminated with oil products. Storm sewage from the petrochemical part is mainly contaminated with phenol.
The Central Sewage Treatment Plant (CST) is located within the boundaries of the Plant. Its purpose is to treat sewage from the entire Plant and other operators located within the Plant to meet the parameters specified in the water management conditions permit. All sewage is treated in a 4-stage cycle. There are also 21 local pre-treatment plants linked with respective units. They play an important role in reducing the pollution load in sewage delivered to the CST. They are mainly mechanical pre-treatment facilities, and the total amount of pre-treated sewage is appr. 11.306 m3/d.
In 1996, we started implementing a closed water and sewage circuit with purified sewage used as industrial water. This required addition of 3rd and 4th degree sewage treatment to the sewage treatment line and construction of an “inhibitor node”, where treated sewage is inhibited and sanitized with chlorinated water. Sewage water is used as industrial water for cleaning, washing and fire fighting purposes as well as in water cooling systems. The new technologies yielded environmental and economic benefits. The volume of water taken up from the Vistula, and the sewage dumped into it, has significantly dropped.
See The scheme of Central Sewage Treatment Plant
However, the closed water circuit, apart from advantages, led to certain problems and restrictions. In 2002, we resigned from increasing the amount od directed reversed sewage to cooling systems, as it resulted in excessive salinity of the water in the Water Blocks. Thus, in order to be able to continue using recycled water, we will have to reduce salt consumption in the water and sewage system.
In 2008, we reported a 1.9 k Mg drop in the amount of generated sewage as compared to 2007. The difference is mainly due to less waste generated from concrete and debris. The amount of recycled waste remains stable at approx. 90% ratio to generated waste.
| Volume [‘000 Mg] | Volume [‘000 Mg] | |
|---|---|---|
| Waste | 2007 | 2008 |
| Total generated waste, including: | 13,80 | 11,90 |
| – hazardous waste | 4,90 | 4,30 |
| – other waste (excl. municipal waste) | 8,90 | 7,60 |
| Volume [‘000 Mg] | Volume [‘000 Mg] | |
|---|---|---|
| Waste | 2007 | 2008 |
| Recycled | 12,5 | 10,7 |
| Total neutralised waste, including: | 0,7 | 0,5 |
| – thermal | 0,4 | 0,3 |
| – stored | 0,0 | 0,2 |
| – other | 0,3 | 0,0 |
| Stored waste | 0,6 | 0,7 |
ORLEN Group's brands
