Following earlier investments in Den Hartogh's Botlek waste water treatment plant, attention turned to making the company's Dordrecht Depot greener. After approval by the Board, a series of changes were implemented on 25 April 2014.
The initiatives will result in improved energy efficiency of the waste water treatment process, higher quality of the treated water, less waste water and lower carbon emissions. They will bring the Dordrecht Depot up to the required environmental and technical standards.
Furthermore, over the last few years the cost for waste water removal and subsequent treatment by third parties has increased significantly. The changes will therefore lead to cost savings for Den Hartogh.
The major part of the upgrade concerns the installation of a bioreactor and a continuous molecular membrane system for the cleaning of the water from the bioreactor. A heat recovery system of 500 kW/hour has been added. A Supervisory Control and Data Acquisition (SCADA) system was also installed to achieve improved control of the whole process.
The changes will mean an 80% reduction in the total annual waste load, as well as a reduction in the gas consumption of the steam boilers. The result will be a considerable reduction of CO2 emissions, and in parallel an increase in the quality of waste water.
In practice this will mean:
On a 14 hour/day basis with a capacity of 500 kW/hour, energy re-use will amount to 25,200 MJ per day, which is equivalent to pre-heating 200 cubic metres of feed water from 12 to 42 ºC.A reduction of 350 tons of CO2 emissions per year, which is equivalent to removing 174 medium-sized cars from the road.
The total investment for this upgrade is around € 500,000, with a payback time of just over three years.