WATER SUPPLY
Drinking water
Process water
Fully desalinated water
Circulation water
1893 First water supply in Leverkusen
1909 Start of production of desalinated water in Leverkusen
1912 First process water supply at Uerdingen site and also construction
of first cooling tower to conserve cooling water
1917 Construction of the first drinking water supply
and a softening plant in Dormagen
1925 Construction of the first river water plant in Uerdingen
1925 Start of centralized, combined heat and power generation
in Leverkusen
1934 Separation of process and drinking water at the Leverkusen site
1939 Construction of the first desalination plant at the Uerdingen site
1950 Completion of the river water plant in Leverkusen
begun during the war
1957 Construction of the Hitdorf water plant and the long-distance
pipeline to Leverkusen
1958 Maximum process water production of 10,000 m³/h achieved in
Uerdingen
1960 Construction of the Monheim water plant and connection to the
Leverkusen water network through a long-distance pipeline to Hitdorf
1961 Construction of the first cooling tower in Dormagen
1962 Production of 400 m³ of fully desalinated water per hour in
Leverkusen
1969 Reconstruction of the Leverkusen river water plant
1973 Introduction of the fluidized bed process in fully desalinated water
production for reducing consumption of hydrochloric acid and sodium hydroxide
1975 Construction of a partial stream filter in Uerdingen to reduce
the contaminant content in circulation water
1983 Use of waste heat in the Uerdingen fully desalinated water plant for
more efficient degassing
1987 Conversion of a Dormagen fully desalinated water plant to the
fluidized bed process
1994 Modernization of the Hitdorf drinking water plant
1997 Reconstruction of the central control center in Leverkusen
2002 Commissioning of the first GRP cooling tower in Uerdingen
2005 Commissioning of the pilot plant for treating additional cooling tower
water by membrane technology in Uerdingen
2006 Construction of the Monheim – Dormagen Rhine culvert for supplying
process water
2008 Reorganization and streamlining of the water supply
2011 Renovation of the control system for the Uerdingen river water plant
2013 Construction of a new cooling tower in Dormagen
HISTORY OF
WATER SUPPLY
WATER SUPPLY – Introduction
CURRENTA consumes approximately 400 million
cubic meters of water every year for cooling,
generating steam and rinsing, and for use as a
solvent and drinking water.
INTRODUCTION
An overview of our water:
Surface water
Drinking water
Process water
Circulation water
Fully desalinated
water
Boiler water
Bank infiltrate
Groundwater
Fully desalinated water
High-purity water, basis for steam generation and raw material for production.
Boiler water
Similar to fully desalinated water, but conditioned and pre-heated.
Drinking water
Water just like what comes out of the faucet in private households. Quality in line with the German Drinking Water Ordinance.
Process water
Clean water that is not monitored in line with the German Drinking Water Ordinance, for cooling, cleaning, etc.
Circulation water
Conditioned process water that is cooled in cooling towers and used multiple times.
WATER SUPPLY – Introduction
Water is our most valuable foodstuff. It is essential for agricultural operations and thus also for the production of the majority of foodstuffs. We use water every day for personal care, for hygiene and in our households. And last but not least, clean water is also crucial for most industrial processes. It is therefore understandable that the first reason for passing the European Water Framework Directive (EU-WFD) reads: “Water must be managed and protected. It is not merely a consumer product, but a precious natural resource, vital to future generations as well as our own.”
Despite its vital importance, we take it for granted that the required amount of clean water will come out of the faucet as soon as we turn it on. To ensure that this is the case at CHEMPARK and the surrounding communities, CURRENTA’s water supply staff are faced with a large number of technical challenges each and every day. And since the natural water supply – be it surface water or groundwater – is constantly replenishing itself, but not to the extent that we would like, we conserve this valuable resource. The water that we treat is a balanced mixture of surface water (from the Rhine, to be precise), bank infiltrate (also from the Rhine) and a small amount of groundwater. This variable water sourcing also ensures exceptional security of supply.
As a competence center for pure water for the chemical industry, CURRENTA Water Supply reliably provides the three CHEMPARK sites in Leverkusen, Dormagen and Krefeld-Uerdingen with the volume of water they require, in whatever quality they desire – a total of 400 million cubic meters per year, which is more than the capacity of the Tegernsee lake. Quality ranges from process water to drinking water that complies with the German Drinking Water Ordinance and high-purity fully desalinated water. Through our own long-term water rights, reliable production facilities and highly qualified staff, we safeguard security of supply for our customers at CHEMPARK and also in the neighboring communities. The Water Supply segment provides more than just water, however. It also provides support in all issues relating to water legislation, keeps you informed of current issues and represents you in dealings with the authorities and institutions.
WATER SUPPLY – Prudent water management
When it comes to extracting, using and treating
water, CURRENTA Water Supply undertakes
wide-ranging activities to protect waterways
and the environment.
PRUDENT
WATER MANAGEMENT
Protecting waterways together
To ensure it remains possible to supply clean water in the long term using treatment methods that are in harmony with nature, CURRENTA Water Supply has joined forces with trade associations (for example the IAWR – International Association of Waterworks in the Rhine Catchment Area) to protect waterways, because “Protecting the water situation [...] will have economic benefits [...]” (EU-WFD).
CURRENTA also maintains its own partnerships with agricultural firms to prevent any impairment of water quality before it occurs. Thanks to a closely linked groundwater measuring network and using hydrogeological models, we monitor groundwater flows around CHEMPARK and safeguard a reliable water supply while also protecting the groundwater. CURRENTA water managers also investigate the conditions in the ground and create detailed maps showing the interaction and behavior of groundwater flows in relation to the level of the Rhine and layers of soil.
Precise knowledge of these correlations are necessary before a well can be drilled, for example. At the same time, we are in close contact with the relevant authorities, because the legal situation governing water always demands collaboration with the local authorities responsible. Monitoring groundwater flows is also mandatory.
Avoiding environmental impact
When taking water from wells, we are generally extracting Rhine bank infiltrate that quickly replenishes itself. This comes from the river through the sand and gravel near the bank. Adsorption and biological decomposition processes mean that it is naturally cleansed of many unwanted ingredients. In this way, we are also able to conserve groundwater resources.
We monitor the water quality of the Rhine. After all, this has a direct impact on the quality of drinking and process water at CHEMPARK and the treatment it requires. The used and cleaned cooling and process water that we feed back into the Rhine is noticeably different to river water. It is considerably clearer. However, it is also somewhat warmer. To minimize the warming of the Rhine, we also use closed circuits with cooling towers. We replace the water lost through evaporation. However, since this is only a negligible amount, this also enables us to reduce the amount of fresh water we extract.
Using energy efficiently
We and our staff systematically use every opportunity to save energy. In the last few years, Water Supply has achieved an annual increase in efficiency of approximately one to two percent. Employees make their own
suggestions for improvements, which is a great help to us in continuously improving our technology and reducing energy consumption. Our industrial cooling systems apply the compression principle and operate many times more efficiently than refrigerators or air-conditioning systems. While a typical household refrigerator generates four kilowatts of cooling capacity from one kilowatt hour of energy, our plants achieve a cooling capacity of 150 kilowatts from the same energy.
WATER SUPPLY – Water extraction plants
CURRENTA Water Supply extracts cooling and
process water primarily from river water plants
on the Rhine, while wells form the basis for the
production of drinking and fully desalinated water.
Schematic of a horizontal filter well
Schematic of a vertical filter well
Tertiary (fine sand) Meadow loam
Sand Humus
Quaternary (sandy rough gravel, aquifer)
Outer observation pipe
Inner observation pipe
Siphon system Counter filter Filter gravel Sump pipe DN 400 Borehole diameter 1.00 m Intake manifold DN 200 Extension pipes DN 400
Stoneware rib filter DN 400
At-rest water level Operating water level
Meadow loam Humus Collection shaft Holding pipe Tertiary (fine sand) Quaternary (sandy rough gravel,
aquifer)
Since we have such a wide range of very variable “sources” for our water, we have to transport it to the treatment plants using different extraction units. We extract surface water from the Rhine using intake structures, while bank infiltrate and groundwater are taken from wells. We use both horizontal and vertical filter wells.
Intake structures in the river water plant
Surface water is taken from the Rhine using intake structures. Depending on the composition of the riverbed, these can be constructed on the bed of the Rhine, at the edge of the riverbank or in a kind of quay wall. Intake structures in the riverbed have the advantage that they can still take in water even when the river level is low. However, they also take in a large amount of bed load with the river water, which means they are generally not in operation when the river level is medium or high. Intake structures on the bank, on the other hand, require a minimum water level and have to be closed off at breaker level if there are any floating pollutants (oil films on the river water, for example).Horizontal filter wells
Horizontal filter wells make use of the approximately 20-meter-thick gravel and sand in the low terrace and lower mid-terrace of the Rhine. The shaft diameter is generally around five meters. At a depth of just under 20 meters, 30- to 60-meter-long filter sections extend outward in a star formation. Some of the wells have been in operation for over 50 years. Some are located in the Rhine’s natural flood plain and still contribute to CHEMPARK’s supply even when the river is in spate.
Vertical filter wells
Wells of this kind are far smaller than horizontal filter wells. The filter pipes through which the groundwater flows into the vertical filter wells stand vertically and are part of the significantly narrower well shaft. Often, an unassuming access cover is the only manifestation of this kind of well above ground.
WATER SUPPLY – Treatment processes
Process water, cooling water, fully desalinated
water and drinking water – CURRENTA Water
Supply employs a wide variety of treatment
processes.
Schematic of bank filtration process
Well
Clean water outlet
Structure of a filtration plant
Gravel/
sand fill
River
Raw water intake
Passage of the river water
through the ground
To produce process water, cooling water, fully desalinated and degassed water and drinking water, we employ a balanced mixture of tried-and-tested and future-focused technologies. We also regularly look into the use of alternative treatment processes. Depending on the quality of the raw water and the type of water produced, we employ different processes that our plants combine in different ways.
Coarse cleaning
Coarse cleaning is primarily employed as the first treatment step for surface water (i.e. Rhine water) that CURRENTA only uses for process water production. This removes coarse pollutants from the raw water (such as pieces of wood or plastic). To this end, we pass the water through rakes and screens. There are usually several of these in succession with decreasing mesh sizes.
Filtration
During filtration, water is passed from top to bottom through gravel or sand filters (depending on the purity required). While the water is flowing through the cavities in the gravel fill, the dirt particles come into contact with the grains of the filter material, where they are deposited and thus removed. Having been freed of pollutants in this way, the clear water leaving the filter is already of sufficient quality for process water.
Bank filtration
Bank filtration involves taking water from a waterway – in our case the Rhine – by drilling wells close to the river bank. Due to the proximity of river and well, such wells provide virtually pure river water and only very limited amounts of groundwater. On its way from the Rhine to the shaft, the water passes through the layers of soil of the bank, which act as a large gravel filter. Alongside the mechanical removal of suspended particles, biological decomposition processes also take place here that further improve the purity of the water. The bank infiltrate can therefore be used as process water without any further treatment. To achieve drinking water quality, further treatment steps are required.
WATER SUPPLY – Treatment processes Water outlet Air outlet Water intake Air intake Trickling filters
Moist waste air
Warm water intake Dry air intake Cold water outlet
Aerating and deacidifying
To remove carbon dioxide from the water and at the same time enrich it with oxygen, we send it down a cascade of pipe grids. It flows down the cascade as a thin film of liquid, thus bringing it into close contact with air that is fed through the plant in a counterflow from bottom to top. The large surface area of contact between water and air ensures there is an effective exchange of carbon dioxide (from water to air) and oxygen (from air to water).
Adsorption
The water is freed of trace materials and organic
compounds in adsorption filters. In a similar way to gravel filters, the water flows through a fill from top to bottom. In this case, the fill consists of activated carbon or special resins. The pollutants attach themselves to the surface of the filter material and remain there. We use this process to remove organic compounds, for example, that can affect the smell or taste of drinking water.
Ion exchange
In the first desalination step, we remove the positively charged cations such as calcium, magnesium and sodium. To this end, the water flows through a fine-grained resin fill. The ions bond with the artificial resin beads and displace H+ ions (protons) from their surfaces, which pass into the water. In the downstream anion exchanger, the same principle is used to remove negatively charged anions (for example sulfate or chloride ions) from the water and replace them with OH ions from the surface of the resin. This is how salt ions are removed from the water. The H+ and OH- ions released into the water by the resins in the two exchange stages react with each other and form
H2O – water.
Material transfer using a pipe grid cascade Schematic of a cooling tower
Water outlet Air outlet
Degassing
As well as the salt ions, we also have to remove the gases that are dissolved in the water so that it can be used for generating steam. These gases are primarily carbon dioxide and oxygen. As described in the “Deacidifying” section above, carbon dioxide can be removed using trickling filters. To remove the dissolved oxygen, we first add hydrogen to the water in Leverkusen and Krefeld-Uerdingen. It is then fed through a contact container filled with a catalyst in which the two dissolved gases react with each other to form water. In addition, or alternatively (as in Dormagen), we can remove dissolved gases using a vacuum. This involves sucking them out of the water, so to speak.
Stabilization
Depending on the purpose of the water, we also add various substances that prevent the growth of bacteria, corrosion or barnacle growth. We use hydrogen peroxide or chlorine to prevent biological growth and protect the equipment in the water cycle, such as pipelines and heat exchangers, from loss of efficiency and blockages. Sodium hydroxide solution or ammonia, for example, are used as corrosion inhibitors in water destined for steam generation in power stations.
Cooling
Circulation water used for cooling purposes in customer plants is cooled in central cooling towers. In these towers, the water is atomized into fine droplets, trickles through filters on the inside of the tower and is collected in the cold water basin. At the bottom of the cooling tower, ambient air comes in from the side and comes into contact with the water in a counterflow. A small amount of the circulation water evaporates in the process. The evaporative heat loss ensures the remaining water is cooled efficiently. The now moist air is then extracted through the top of the cooling tower by a fan. Evaporation alone can cool the water to as much as 15 °C below the ambient (air) temperature (depending on the relative humidity). We replace the water lost through evaporation.
Pre-heating
In some cases, the fully desalinated water that we supply for steam production in plants is already pre-heated. This enables us to simultaneously use the existing waste heat, which avoids the outlay involved in releasing it into the surroundings and increases the efficiency level of the plants supplied. Process Drinking w ater Pr ocess w ater Fully des ali-na ted w ater Circula tion w ater Boiler w ater Coarse cleaning Bank filtration Gravel filtration Aerating, deacidifying Adsorption Ion exchange Degassing Stabilization Cooling
An overview of the processes and
their areas of application
CURRENTA Water Supply boasts comprehensive know-how and many years of experience in applying the processes described above, as well as detailed knowledge of their strengths and weaknesses. Combined with CURRENTA’s skills in the field of automation, this enables us to select the best combination of processes available to match the relevant boundary conditions, which ensures a highly efficient water supply.
River water plant Sedimentation basin Pit Process water network Sediments Rhine
Inlet structure Pumping station Gravel filtration
Process water Backwash water Direct transfer Feed pumps H2O2/Ag Rinse water Raw water Inland waterway
Circulation water cooling
Settling basin
Analytical cooling water monitoring
T 1
P 1 T 1
Sewer Partial flow filter
Biocide Inhibitor Water added P Purging Overflow Air Air
Dispensing and monitoring
Heat exchanger
Drinking water treatment
Full desalination plant
Disinfection Raw water pumping Deacidifying / aerating Filtration and adsorption of organic water ingredients
Rhine
Drinking water protection zone
Deacidifying
Network pumps
Activated carbon double-layered filter
Preventive chlorination Network Y Process water Conductivity approx. 700 µS/cm Catalytic O2reduction Plants Power plant Neutral filter Sewer Slightly acidic cationic exchanger H+ form Regeneration
6% HCl Regeneration3% NaOH Regeneration3% NaOH
Regeneration 6% HCl H2 Storage Mixed bed Cationic
exchanger Tricklingfilter exchangerAnionic
CO2 Slightly acidic cationic exchanger Na+ form Fully desalinated water Conductivity < 0.2 µS/cm SiO3 -CO3 -Cl -SO4 -Na+ Mg++ Ca++ Conductivity < 20 µS/cm Air OH -H+
Published by
Currenta GmbH & Co. OHG 51368 Leverkusen
