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[...]The first step of operationally reliable and efficient wastewater treatment The separation of solids in wastewater with screens and fine screening systems is the first step in municipal and industrial wastewater treatment. The main task here is to remove all coarse and foreign materials that could inhibit or hinder the function of subsequent wastewater treatment stages. The following factors, among others, must be taken into account when planning an operationally reliable solids separation solution: Maximum required hydraulic throughput Expected screenings quantities Required bar spacing or separation capacity for solids Influence of sewer system (surges, deposits, pumping stations, etc.) Redundancy requirements Installation situation (channel, tank) Feeding (by gravity, pump, hoist, ...) All this information and framework conditions are then taken into account for the choice of the right machine technology and determine the number, size and type of screening systems. Machine Technology A Wide Range of Screens, Fine Screens and Ultra-Fine Screens for any Application HUBER has decades of experience in dimensioning and selecting the optimum machine technology for each individual mechanical cleaning application. As different requirements also demand different screen systems, HUBER has developed a wide range of various screens, fine screens and ultra-fine screens , which are in use in thousands of installations worldwide. The separated and removed screenings with household waste, faecal matter, toilet paper and mineral solids are then passed on to the screenings treatment system , which is ideally planned together with the screening plant.[...]

[...]Clean and safe solutions for drinking water applications Drinking water must go from the drinking water reservoir into the mains in a hygienically perfect condition. There are therefore high demands on the structural design and hydraulic equipment of water reservoirs. Typically, the water surface in a reservoir is constantly in motion. While air streams out during filling, the water reservoir draws in ambient air during emptying. In this respiration process, particles contained in the air enter the drinking water along with oxygen and nitrogen. Since organisms such as germs, viruses, spores or pollen are also present, this results in severe hygiene problems. Even the elevated reservoir on a greenfield site is not spared from this. HUBER has adapted solutions for these cases: Specially developed aeration and deaeration systems for drinking water reservoirs remove the finest particles from the air. Louvres can keep coarser dust, insects or leaves away from the water chamber. The first stage of air cleaning can be achieved using HUBER Louvres TT2.JW/TT10.B . Alternatively, the use of HUBER Ventilation Chimney BKA models is also possible. HUBER offers a hygienic solution for air filtration with one of four HUBER Aeration/Deaeration Plant BLA systems differing in throughput. These systems use HEPA filters to filter the air before it can enter the drinking water reservoir. As a result, hygienically pure, clean filtered air is always present in the reservoir.[...]

[...]Saalbach-Hinterglemm, Austria Fine screening systems are an interesting alternative to primary settling tanks when it comes to changing the sludge stabilisation process from aerobic to anaerobic. Compared with a traditional primary clarifier with a retention time of 0.5 to 2 hours, a fine screen achieves the same or better reduction rates, which take effect within a few minutes whilst requiring only a fraction of the space and volume. Energy savings and biogas yield through carbon removal Switching from aerobic to anaerobic sludge stabilisation can reduce aeration costs by around 20–25%. This reduction is achieved through carbon removal, usually through a primary clarifier or, as in the case of Saalbach, using HUBER fine-screen technology prior to biological treatment. This has also resulted in a further positive effect in terms of energy generation through the utilisation of primary sludge, which is used directly for the production of biogas or to increase on-site electricity generation. Seasonal utilisation of the Saalbach sewage treatment plant The municipality of Saalbach, known as a winter sports destination but also enjoying high visitor numbers during the summer, operates a sewage treatment plant at Glemmtaler Landesstraße 554 with a design capacity of 49,000 population equivalents (PE). Due to seasonal fluctuations, its actual utilisation varies between 10 per cent during the off-peak periods and 100 per cent during the peak season. Capacity limits and lack of primary treatment The Saalbach wastewater treatment plant already had two digestion tanks and a combined heat and power (CHP) unit, but no primary treatment. The digestion process had been fed exclusively with mechanically thickened excess sludge. With increasing tourism, particularly during the winter season, the plant approached its authorised capacity of 49,000 PE60 on some days. It was therefore necessary to find a solution to relieve the load on the biological treatment process. Plant expansion to relieve the load on the biological treatment process The first studies for the expansion were carried out in mid-2019. The aim was to relieve the biological treatment process through primary treatment, whilst simultaneously improving the energy balance through biogas production and electricity generation and reducing the energy required for aeration. Lack of space and integration of the mechanical primary treatment The aerial view shows that, nestled between the northern slope, the Glemmtal main road, the Saalach river and the southern slope, there was no space for a primary treatment tank. The plot on the western side was not available. The sketch outlined in red shows where the lifting station, the mechanical primary treatment (drum screen) and a primary sludge thickener (disc thickener) could be integrated into a confined space after the grit chamber and before the aeration stage, and in the immediate vicinity of the digestion tanks. Initial trial operation under winter conditions From mid-February 2020 to mid-March 2020, during the winter season and in freezing temperatures, the first operational trial was carried out using a demonstration unit of the HUBER Drum Screen LIQUID housed in a container with a 0.2 mm mesh. Optimisation of screen surface cleaning for grease-laden sludge Although the first trial run had to be cut short after a short time due to the coronavirus pandemic, it was already apparent that screen surface cleaning was, and remains, the key criterion; this is why the LIQUID screen was fitted with additional air-jet cleaning and a modified high-pressure cleaning system, enabling it to function reliably even with very grease-laden primary sludge. Thanks to the air-jet cleaning system, the drum screen produced a thicker primary sludge than was the case with spray-water screen surface cleaning, which is fed from the finely screened inlet. Second trial run confirms high COD reduction The second trial run took place between December 2021 and March 2022. This demonstrated that COD removal rates of 25–40 per cent (with and without the use of polymers) could be achieved, thereby reducing the load on the subsequent biological treatment stage through the removal of pollutants from the wastewater. Implementation and commissioning ahead of the 2025 World Ski Championships Following the local council’s decision and the granting of a water law permit by the Salzburg Provincial Government, construction of the primary treatment plant, including its integration into the existing system, began in late summer 2024, half a year before the 2025 World Ski Championships. Commissioning took place on 27 January 2025. At the end of the 2025 winter season, the primary treatment system was taken out of service until it was put back into operation during the 2025 summer season, from early June to late September. Operational results during seasonal operation Depending on the proportion of wastewater routed through the primary treatment system, the operational results showed a COD reduction of 26 to 33 per cent (daily composite sample) prior to entry into the biological treatment stage, in both winter and summer operation. It should be noted that this was achieved without the use of polymers. Flexible feeding and control of the C/N ratio Plant manager Josef Ebner and his colleagues are particularly impressed by the flexibility and ease of maintenance of the process: The mechanical primary treatment system is fed on a case-by-case basis and with variable flow rates from a load of around 15,000 p.e. It can be brought into operation within a few minutes. The C/N ratio for denitrification is adjusted to the required value by controlling the volume of influent withdrawn after the grit chamber and passed through the fine screen. Positive effects on energy consumption and electricity generation During peak load periods, the measure implemented leads to a significant reduction in the aeration energy required in the aeration tanks and, at the same time, to an increase in biogas yield, which in turn results in higher in-house electricity generation. Image Gallery Sludge Thickening: Primary sludge from the HUBER Drum Screen LIQUID in the HUBER Disc Thickener S-DISC HUBER Drum Screen LIQUID manufactured in the HUBER production in Berching HUBER Drum Screen LIQUID at the Saalbach WWTP HUBER Disc Thickener S-DISC[...]

[...]Malta The Ta' Barkat sewage treatment works, often referred to as the Malta South STW, is at the heart of Malta’s wastewater management system. It is situated near Xgħajra on Malta’s south-east coast and officially came into operation in 2011. It is the country’s largest sewage treatment works and treats around 60,000 m³ of wastewater every day. This corresponds to around 80 per cent of the island’s total wastewater volume. The plant uses a modern biofiltration process that alternates between aerobic and anoxic environments to efficiently treat the wastewater. Its commissioning has significantly improved water quality at beaches in the south, such as Marsascala and Kalkara. ‘New Water’ project An important feature of Ta’ Barkat is its reclaimed water treatment plant, which allows the water to be used for agricultural irrigation. Here, the already treated water is further purified through ultrafiltration (UF) and reverse osmosis (RO) to such a high standard that it can be used as high-quality irrigation water for agriculture. The result is Class A water, the quality of which, according to the operator Water Services Corporation (WSC), even exceeds the standards set by the Food and Agriculture Organisation of the United Nations (FAO) for the irrigation of food crops. Currently, up to 9,000 m³ of ‘New Water’ is produced daily. However, it is expected that daily production will need to be increased to 20,000 m³/d by 2028. In the long term, the project is intended to cover up to 35 per cent of the agricultural sector’s water requirements. The main objective is to achieve a ‘net-zero impact’ on the natural water cycle by replacing illegal or excessive extraction from wells with sustainable reuse. To protect the downstream ultrafiltration and reverse osmosis plant (UF-RO system), drum filters were originally used as ultra-fine screens downstream of the secondary clarifier. However, these did not provide the necessary purification performance. The TSS values in the effluent from the drum filters were regularly in the range of 20–40 mg/l, leading to high operating costs for the UF membrane and, consequently, plant downtime. For this reason, the operator conducted an in-depth review of alternative technologies for ultra-fine filtration of the treated effluent. Ultimately, it was decided to replace the drum filters with cloth filters in order to ensure a better effluent quality for the operation of the UF-RO system. HUBER solutions in use In January 2024, HUBER SE was commissioned via a local partner to upgrade the plant with a cloth filtration stage. At the WSC’s request, the system was installed in tanks. Following intensive detailed discussions and coordination with all parties involved, three HUBER Pile Cloth Media Filter RotaFilt®, size 2700, were delivered to Malta in November 2024. After more than a year of satisfactory operation, a routine inspection carried out by a HUBER service team in collaboration with the operator identified potential for improvement in the overall functioning of the plant. The aim is to increase plant availability and improve operational performance. This is because the pile fabric filtration stage must also significantly increase its net daily throughput in the course of 2026. Meanwhile, construction work on the expansion of the downstream filtration stages is also in full swing, to ensure the plant is optimally prepared for future requirements.[...]

[...]Totalphütte, Alps, Austria The Totalphütte was originally a site hut for Vorarlberger Illwerke AG and served as accommodation for the construction workers building the Lünersee lake dam. Since 1964, the Austrian Alpine Club has been running the hut as a mountain refuge. Following a number of refurbishments and the reconstruction of the hut – it was severely damaged by a dust avalanche in 2019 – it has since become a popular destination for walkers and those conquering the Rätikon’s highest peak, Schesaplana, at 2,965 m. Wastewater treatment remains an important issue even in high-alpine environments. A HUBER Micro Strainer ROTAMAT® Ro9 screen is in use at the Totalphütte. It treats the wastewater daily from up to 1,000 day visitors, plus a further 150 people who stay overnight at the hut. Seasonal operation presents challenges Due to the short operating period of the sewage treatment plant, keeping the plant running smoothly and reliably is always a major challenge. This makes the pre-treatment of the wastewater all the more important before it is fed into the biological treatment stage. Furthermore, ease of operation of the plant’s machinery is of great importance. The plant must be commissioned at the start of the season in July with just a few simple steps and then decommissioned again in September after a short but intensive period of operation. A straightforward start-up and shutdown procedure was therefore a prerequisite for the plant operator. During our conversation, the hut tenant expressed her delight at how smoothly the entire project had been carried out. She also highlighted that the workload at the sewage treatment plant has reduced a lot since the new HUBER screening system was installed. An efficient solution for mountain regions and similar areas The HUBER Micro Strainer ROTAMAT® Ro9 is simple and flexible to use and easy to transport to any location. At the Totalphütte, it has been reliably reducing the load on the biological treatment system since its installation, as the screen thoroughly removes foreign matter. Thus, a simple helicopter flight has made it possible to clean the water resources in the mountains sustainably and protect the environment.[...]

[...]Bickenbach, Germany The European water sector will face enormous challenges in the coming years. Implementing the new EU‑Urban Waste Water Treatment Directive (UWWTD) and ensuring the sustainable protection of our water resources will be a significant collective task. UWWTD is therefore rightly regarded as a milestone that will shape urban water management across Europe in the long term: stricter requirements for the removal of phosphorus and nitrogen, energy neutrality and, above all, the widespread introduction of the fourth treatment stage. All sewage treatment works with a capacity of more than 150,000 population equivalents (PE) and, in sensitive areas, those with more than 10,000 PE, must retrofit this additional treatment stage by 2045. It is not yet clear how many sewage treatment works in Germany and Europe will actually be fitted with trace substance removal systems. However, it is expected that in Germany alone, around 600 sewage treatment works will be fitted with a fourth treatment stage. To date, over 60 German sewage treatment works have already been upgraded with an industrial-scale fourth treatment stage, including 33 plants in Baden-Württemberg, which, together with Switzerland, has taken on an important pioneering role in this field. A small selection of these successfully implemented case studies is presented in the fact sheets opposite. The projects impressively demonstrate that, from a technological perspective, the successful implementation of an industrial-scale fourth treatment stage is already possible today. It is now up to European policymakers to promptly develop and present a pragmatic solution for the financing of the UWWTD that is acceptable to all parties.[...]

[...]Baden-Württemberg, Germany A fourth treatment stage is currently being built at the sewage treatment works in Schwäbisch Hall, Markgröningen-Talhausen, Vörbach-Pfalzgrafenweiler and Meßkirch in Baden-Württemberg. These treatment works have opted for the GAC (German: GAK) process, which uses granulated activated carbon for adsorption. Upstream of the trace substance removal stages, there is a multi-stream pre-filtration system at each site, all of which have been equipped with the new HUBER Pile Cloth Media Filter RotaFilt®. These reliably protect the subsequent GAC‑adsorption process from dirt and contaminants, thereby ensuring stable and low-maintenance plant operation. In Vörbach-Pfalzgrafenweiler, twelve HUBER Activated Carbon Filter CONTIFLOW® GAK units are used as the GAC stage. Trace substance removal and phosphorus removal At the Eglosheim-Ludwigsburg wastewater treatment plant, powdered activated carbon is dosed directly into the biological stage to remove trace substances. Here, cloth filtration acts as a conventional final filtration stage and ensures that no loaded activated carbon particles from the secondary clarifier enter the receiving watercourse. In all five projects, cloth filtration can also be operated in combination with coagulant dosing as flocculation filtration, should the most thorough possible removal of phosphorus be required. Outlook and project status All five plants are still under construction at present. The fourth-stage treatment facilities in Schwäbisch Hall and Eglosheim-Ludwigsburg are expected to be operational by 2026. The other projects are expected to be operational in 2027.[...]

[...]Kreßberg, Germany With the new EU Urban Waste Water Treatment Directive (UWWTD, German: KARL), phosphorus removal at sewage treatment works is increasingly coming into focus. At the same time, however, phosphorus loads from sewage treatment works are also one of the reasons why Germany still fails to meet the requirements of the European Water Framework Directive (WFD 2000). Not least for this reason, further measures will be necessary at many sewage works in the future. Flocculation filtration in Kreßberg At the Kreßberg (GK3) sewage treatment works in Baden-Württemberg, this issue is now viewed with confidence. The new flocculation filtration system was commissioned there in spring 2025. A HUBER Pile Cloth Media Filter RotaFilt® 2700 with four filter discs is used as the flocculation filter. Together with an optimally adjusted precipitant dosing system, it ensures that the annual average total phosphorus concentration in the treatment plant effluent never exceeds 0.2 mg/l at any time. At the same time, the cloth filtration enables an effluent that is virtually free of solids to be achieved: ‘Last year, the turbidity in the treatment plant effluent was almost always < 1.0 FNU,’ said plant manager Karl Prosy with satisfaction. HUBER’s products and solutions for phosphorus removal are already being used in other projects as well. This enables the increasing requirements for wastewater treatment to be met and the plants to be equipped for the future.[...]

[...]Worldwide Grit chamber cleaners are generally reliable and safe, working around the clock, come rain or shine. Nevertheless, the ravages of time take their toll on the structure. After 30, 40 or even more than 50 years, even carefully maintained and well-looked-after cleaners eventually reach the end of their service life. Paving the way for the future It is wise to plan for the future cleaning of your longitudinal grit trap early on and with foresight. As is so often the case, there are various solutions available for this. However, before addressing the issue of grit channel clearance, it must first be clarified whether the old concrete grit channel still meets current requirements – in terms of separation efficiency, for example – and what condition the concrete structure is in. This will determine whether a new build or a possible refurbishment (retrofit) without costly civil engineering works is required. If the decision is made to carry out a retrofit, one either seeks a suitable replacement for the grit channel cleaner or explores a new, innovative method of removing the grit from the grit channel. Unfortunately, replacing the cleaning system presents many difficulties, as a one-to-one replacement is usually not possible. On the one hand, many of the manufacturers of those scrapers are no longer on the market, and on the other, alternative products are completely unique. Optimal results with modern grit traps HUBER offers an innovative alternative: the HUBER Longitudinal Grit Trap ROTAMAT® Ro6 with a grit removal screw. What makes it special is the robust screw conveyor at the bottom of the grit channel. This screw, with its hollow shaft, extends along the entire length (up to 42 m) of the grit channel and conveys the sediment step by step to the grit pump (centrifugal pump or pneumatic lift). Blockages in the grit pump, as is often the case with blade-type scrapers, are a thing of the past, as the grit is fed to the pump in small batches. Thanks to the use of the grit removal screw at the bottom of the grit channel, bridge-mounted scrapers are a thing of the past, and the grit traps can now be fully covered to prevent odour emissions. HUBER can, as usual, supply other internal components, such as aeration or grease removal systems, in stainless steel to suit the specific concrete structure. We also provide a comprehensive engineering package. If the old grit channel is to be optimised not only for grit removal but also in terms of separation efficiency, HUBER offers the ideal solution in the form of the innovative HUBER Grit Trap GritWolf® with an integrated lamella separator. In this case, however, the cross-section of the grit channel must be adjusted accordingly. In recent years, HUBER has successfully supplied the solution with the grit removal screw at the bottom of the channel. Among other projects, large mechanical treatment stages have been commissioned in Bahrain, Saudi Arabia, Lithuania and the USA, either as new builds or retrofit projects. This impressively demonstrates that HUBER offers the right solution for every grit separation application.[...]

[...]Every wastewater regulation specifies a limit value for ‘lipophilic substances’, which in practice are referred to as grease. As a rule, more than 90 per cent of the total grease concentration is often present as dispersed grease particles and emulsified grease. Conventional grit and grease traps at sewage treatment works can only retain non-dispersed, floatable grease (DWA M760). The remaining dispersed substances are separated in the biological treatment section of the sewage treatment works. Various grit chamber solutions Factory-built grit chambers are often combined with grease traps (floating-material separators) (DIN 19569-13). According to DWA, factory-built and cast-in-situ aerated long grit chambers – i.e. grit channels with a specific length-to-width ratio – can be supplemented with a grease trap (grease trap pocket) by means of a slotted partition wall. The HUBER Complete Plant ROTAMAT ® Ro5 has been manufactured for over 30 years using state-of-the-art technology with a separate grease trap, as shown in Figure 1. Factory-built, manufacturer-specific grit chambers do not usually have a separate grease trap pocket, but instead separate the floating matter by means of a submerged baffle at the outlet of the grit chamber. Effective grease separation requires large, calm surfaces to ensure that the floating matter accumulated on the liquid surface is not resuspended. In the case of aerated DWA grit channels with a side-mounted grease trap, the non-dispersed, floatable fats are transferred into the grease trap by the resulting laminar flow and remain there until removal. Factory-manufactured, customised grit chambers which operate without a grease collection trap despite being aerated can only retain non-dispersed, floatable fats to a limited extent due to the very turbulent surface. One exception is the HUBER Complete Plant Hydro Duct ROTAMAT ® Ro5 HD system, as this machine features a non-aerated section with a calm surface. Removal and disposal of floating matter The removal and disposal of retained floating matter are handled in different ways. HUBER grit chambers use automatically operated paddle scrapers without exception (see Figure 2). The accumulated floating matter is pushed along the grease trap pocket or a baffle wall and, at the end, is discharged into a grease collection shaft via an inclined ramp (see Figure 3), having been partially dewatered. A level-controlled screw pump conveys the moist solids, where possible, into a raw sludge shaft (digestion) or into a separate container. Other systems attempt to remove the accumulated floating matter using fixed, height-adjustable pumping equipment, or flush the floating matter into a channel using a large volume of wastewater by raising the water level. In both cases, solid–liquid separation must take place in an external, additional unit to avoid problems in the digester or during disposal by third parties. As a general rule, returning the grease–water mixture to the wastewater stream (upstream of the screen) or feeding it into a wash press should be avoided.[...]