Case study Kalundborg
Source: Kalundborg Forsyning
Ultrafiltration module
Source: KWB
Joint control system
Source: KWB
Fig. 1 Principal of the joint control system
Source: KWB
Description
The Kalundborg Industrial Symbiosis Association exists since 1972 and interlinks thirteen private and public companies. The local industrial sector includes petrochemical, light building construction material, food, pharma, biotech, energy and bioenergy as well as waste processing.
Different circular economy approaches for water, energy and materials are already implemented, e.g. the reuse of cooling water for steam production, the reuse of gypsum from exhaust gas cleaning to produce plasterboards, integrated heat management and the transfer between the industries and the district heating network as well as heat recovery from process water for district heating. Even though, the Kalundborg Industrial Symbiosis already recovers and reuses certain materials, water and energy, there are still options to intensify and extend the circular economy related strategies. One aspect is the treatment of wastewaters which is done by two companies Novozymes and Kalundborg Utility.
Ultimate focuses on the optimisation of two WWTPs aiming at developing and implementing a joint control system for both plants, the recovery of the WWTP effluent as fit-for-purpose water and to explore the potential for the recovery of valuable compounds from the industrial wastewater as well as on identifying options to reuse thermal energy recovered from wastewater. Therefore, the symbiotic relationship between Novozymes and Kalundborg Forsyning is extended in the frame of Ultimate to create a win-win situation for both.
Applied technologies
Outcome of assessments
Life cycle assessment:
Water recycling and seawater desalination can reduce freshwater extraction from Lake Tissø and thus reduce local water stress. Water recovery is associated with a higher energy demand and a higher carbon footprint when the recovered water replaces fresh water from Lake Tissø, while it is associated with a lower energy demand and carbon footprint when the recovered water replaces that from seawater desalination. Of all pre-treatment membranes, conventional UF had the lowest carbon footprint and highest yield and was therefore the preferred option. In a large-scale plant, the yield and thus the wastewater production is of importance due to the hydraulic limitation of the secondary treatment.
Total cost of ownership (TCO)
The TCO assesses the treatment of wastewater (with a starting capacity at 2 M m3/year) in Kalundborg comparing four scenarios combining coagulation, sand filtration, and reverse osmosis (RO) with varying filtration technologies: conventional UF (cUF), cUF with UV treatment, ultra-tight UF (utUF), and open nanofiltration (oNF). Over a 30-year evaluation period, TCO ranges from 140 to 150 million EUR, with capital costs and operational costs, in particular electricity cost, as the major cost item. A sensitivity analysis on electricity prices (ranging from 0.121 to 0.134 EUR/kWh) shows a 1-3% variation in TCO across the 4 scenarios, suggesting minor annual fluctuation, however for long-term financial planning and risk management, electricity pricing should be considered. Novel filtration technologies (utUF and oNF) have higher energy demands, increasing their TCO compared to cUF and cUF-UV, which underscores the need for careful energy management to maintain financial sustainability.
Legislation and policy recommendations
Clarifying responsibilities and developing consistent guidelines for water reuse licensing and service provision across the EU are essential to ensure effective practices. The strategic agenda proposes comprehensive coverage of all water reuse types, emphasizing safety, environmental impact assessment, and the integration of reclaimed water into local water balances based on regional circumstances. Future regulations should establish minimum standards for non-agricultural uses, enhance risk assessment, and promote research on innovative water reuse technologies and practices. (see also D1.10)
Applied products
ULTIMATE QMRA tool
To facilitate the design and assessment of treatment trains for water reuse, KWB is supporting the development of an op…
NEXTGEN + ULTIMATE Life Cycle Assessment
Life Cycle Assessment is a standardized framework (ISO 14040) for assessing the potential environmental impacts of a pr…