Mykonos is one of the most renowned tourist destinations in the Mediterranean. Every year, millions of visitors travel to the island to enjoy its beaches, hospitality, and vibrant atmosphere. While fewer than 15,000 people live on Mykonos permanently, the population increases dramatically during the summer season. At peak times, the island accommodates up to 80,000 people per day.
This strong seasonal fluctuation places considerable pressure on local infrastructure. Water supply and wastewater management, in particular, face significant challenges during the busiest months of the year. Hotels, holiday apartments, and tourism-related facilities generate substantial volumes of domestic wastewater, while daily flow rates vary considerably throughout the season.
Outside the island’s main urban areas, many developments lack access to a centralized sewer network. As a result, new buildings rely on decentralized wastewater treatment systems to protect soil and groundwater from contamination. Property owners require reliable treatment performance, low operating costs, and hassle-free operation. At the same time, water reuse has become increasingly important. On islands such as Mykonos, where freshwater resources are limited, treated wastewater represents a valuable resource for irrigation and other non-potable applications.
Through a local partner, PPU Umwelttechnik GmbH became involved in the development of a new holiday complex consisting of several tourist apartments with a total design capacity of 74 PE. The project required a compact and cost-effective wastewater treatment solution capable of producing high-quality effluent for landscape irrigation and site maintenance activities.
For applications such as this, PPU offers proven wastewater treatment technologies under the ClearFox® brand. ClearFox® SBR systems provide an efficient solution for domestic and municipal wastewater treatment. The technology combines excellent treatment performance with low investment and operating costs. Intelligent process control continuously adapts the system to changing inflow conditions and ensures stable biological treatment performance throughout the year, even in highly seasonal applications.
The holiday complex occupies a sloping site characterized by rocky ground and significant elevation changes. These conditions complicated the installation of conventional package treatment plants and limited the available construction options. To make efficient use of the terrain, the project developer designed a series of locally constructed concrete chambers that followed the natural contours of the site. This approach reduced excavation work and minimized the overall construction footprint.
However, the custom-built tank arrangement introduced a new challenge. Many wastewater treatment systems depend on standardized tank geometries or factory-manufactured vessels. The project therefore required a treatment solution that could integrate seamlessly into the existing concrete structures while still delivering reliable biological wastewater treatment.
The characteristics of the incoming wastewater also demanded a highly adaptable process. During peak tourist season, the complex generates substantially higher wastewater flows and organic loads. Outside the holiday period, occupancy levels decrease significantly, resulting in much lower inflows. These fluctuations directly affect biological treatment processes and require a system capable of responding dynamically to changing operating conditions.
Guest comfort represented another important consideration. The holiday complex caters to visitors seeking relaxation and a high-quality experience. The wastewater treatment plant therefore needed to operate quietly, reliably, and without creating odors or other nuisances. At the same time, the available installation area remained limited.
In addition, the project required treated water of sufficient quality for reuse applications. The system needed to consistently reduce organic pollutants, suspended solids, and ammonia concentrations while producing an effluent suitable for landscape irrigation and site cleaning activities.
The client therefore sought a solution that combined flexibility, treatment efficiency, operational reliability, and long-term economic performance within a single integrated system.
PPU Umwelttechnik GmbH supplied a customized ClearFox® SBR kit specifically engineered to match the geometry of the locally constructed concrete tanks. The solution transformed the existing chambers into a high-performance multi-chamber SBR treatment plant, allowing the project to maximize the use of available infrastructure while minimizing additional construction costs.
The ClearFox® SBR process ranks among the most established biological wastewater treatment technologies worldwide. Based on the Sequencing Batch Reactor principle, the system performs all biological treatment stages within a controlled cycle. Advanced process control continuously monitors operating conditions and automatically adjusts treatment cycles according to actual wastewater loads.
Wastewater first enters the primary settlement chamber, where larger solids separate from the liquid stream and reduce the load on downstream treatment processes. The flow then enters a balancing tank, where the system continuously monitors water levels and regulates the transfer of wastewater into the biological reactor.
Within the SBR reactor, the biological treatment process takes place. Fine-bubble membrane diffusers supply oxygen to the wastewater and support the growth of naturally occurring microorganisms. These microorganisms break down organic pollutants and significantly reduce the contaminant load. Intermittent aeration creates ideal conditions for both nitrification and denitrification, enabling the system to remove not only organic matter but also nitrogen compounds efficiently.
Following the biological treatment phase, the activated sludge settles at the bottom of the reactor. This process creates a clear water zone in the upper section of the tank. The system then extracts the treated effluent and directs it to the final polishing stages.
For this project, PPU complemented the biological treatment process with tertiary filtration and disinfection. This additional treatment barrier further improves effluent quality and ensures compliance with the requirements for water reuse applications. The holiday complex now utilizes the treated water for landscape irrigation and the cleaning of paved surfaces, reducing the demand for valuable freshwater resources.
The design values highlight the effectiveness of the installed treatment process. The system reduces COD concentrations from 800 mg/l to below 90 mg/l. BOD levels decrease from 400 mg/l to less than 10 mg/l, while ammonia concentrations drop from 76 mg/l to below 10 mg/l. These figures demonstrate the strong treatment performance achieved by the ClearFox® SBR technology.
The intelligent control system also contributes significantly to operational efficiency. The plant automatically balances hydraulic peaks and adapts to fluctuating wastewater volumes without compromising treatment performance. During periods of low occupancy, a dedicated holiday mode reduces cycle frequency and lowers energy consumption. This feature offers substantial advantages for tourism-related applications that experience pronounced seasonal variations.
Operational reliability represents another key benefit of the system. The ClearFox® SBR plant operates fully automatically and avoids mechanical or electrically powered components inside the wastewater itself. This design minimizes maintenance requirements while increasing long-term reliability. In addition, remote monitoring and remote access capabilities enable rapid response whenever operational support is required.
With the installation of the ClearFox® SBR kit, the holiday complex in Mykonos gained a flexible, economical, and highly efficient wastewater treatment solution. The system treats domestic wastewater reliably, adapts to seasonal fluctuations, and produces treated water suitable for reuse. The project demonstrates how modern decentralized wastewater treatment technology integrates seamlessly into custom infrastructure while delivering sustainable and long-term value for tourism developments in environmentally sensitive locations.
Yes. The ClearFox® SBR system is suitable for a wide range of tourism and decentralized wastewater treatment applications. Typical examples include hotels, holiday resorts, apartment complexes, campgrounds, holiday homes, staff accommodations, and remote communities. Since every treatment plant is individually engineered, the system is tailored to the specific wastewater characteristics, treatment requirements, and site conditions of each project.
No. The ClearFox® SBR system integrates into both new and existing tanks. The technology is compatible with concrete, plastic, and other suitable tank materials. This flexibility makes it an ideal solution for projects with existing infrastructure as well as developments that require custom-designed tank geometries.
Yes. Many tourism-related facilities operate at full capacity only during certain periods of the year. The ClearFox® SBR system includes dedicated operating modes for low-load conditions. These features reduce energy consumption while maintaining the biological activity required for reliable wastewater treatment throughout the year.
Yes. Many projects reuse the treated effluent for landscape irrigation, dust suppression, or site cleaning purposes. The specific reuse applications depend on local regulations and the required effluent quality standards. When necessary, PPU enhances the biological treatment process with additional stages such as filtration and disinfection to meet reuse requirements.
The ClearFox® SBR process is primarily designed for domestic and municipal wastewater treatment. Typical applications include hotels, residential developments, schools, holiday resorts, campgrounds, and small communities. Depending on the wastewater characteristics, PPU can integrate additional treatment stages to meet specific treatment objectives and discharge requirements.
Decentralized locations often lack access to centralized sewer networks, while project requirements vary significantly from site to site. The ClearFox® SBR system combines high treatment performance with low investment and operating costs. Its ability to integrate into virtually any tank geometry and adapt to fluctuating wastewater loads makes it a reliable, cost-effective, and long-term solution for decentralized wastewater treatment projects worldwide.
