Project Report

The operators of the municipal wastewater treatment plant in the Dutch city of Emmen commissioned INVENT to replace the 17-year-old HYPERCLASSIC^®-Mixers with the latest generation models.

The Netherlands have to cope with some demanding tasks in the field of municipal wastewater treatment. The high population of the comparatively small country, the intensive agricultural use and the associated water consumption make wastewater treatment there a supreme discipline. It is gratifying to note that the Netherlands has a very dense network of wastewater treatment plants to which almost 100% of households are connected. This requires outstanding quality and great reliability of the installed products and is reflected in the use of INVENT technology in many Dutch wastewater treatment plants.

One example is the municipal plant in Emmen, a town with more than 50,000 inhabitants in the northwest of the country. Already since 2006, seven HYPERCLASSIC^®-Mixers have been reliably performing their duties in the activated sludge tanks here. Thanks to the unique hyperboloid-shaped mixers, the wastewater is mixed evenly and efficiently.

The systems could easily be used for years to come, but intensive research and development work has enabled the technology to be further improved in the meantime. The HYPERCLASSIC^®-Mixer Evolution 7 has a fluidically optimized mixer body that requires less energy than older models and consequently operates more cost-effectively.

The latest version of the HYPERCLASSIC^®-Mixer provides customers with a revolutionary improved version of the classic hyperboloid mixer – as usual, corrosion- and maintenance-free. For this reason, the operators in Emmen have decided to replace six of the HYPERCLASSIC^®-Mixers with models of the latest version. Competitors‘ mixers are also being replaced, as the plant operators would prefer to rely on the quality of the original from INVENT in the future. This measure has already enabled the Emmen wastewater treatment plant to save 25% of its energy consumption.

Emmen is not an isolated case, but just one of several plants that are converting to HYPERCLASSIC^®-Mixers Evolution 7 because of their higher energy efficiency. Other examples can be found in Dordrecht and Hellevoetsluis in the province of Zuid-Holland. The Dordrecht wastewater treatment plant was even able to save a remarkable 58% of its energy consumption thanks to the replacing former models with the latest version of the HYPERCLASSIC^®-Mixer, while the Hellevoetsluis wastewater treatment plant was able to save 23%.

Meanwhile, the INVENT research department is working on the continuous further development of the mixers and is certain that Evolution 7 will not be the last HYPERCLASSIC^®-Mixer version.

INVENT mixers have been used reliably for years for the desalination process of water from the sea in Oman.

Clean water is a scarce commodity, especially in arid, i.e. hot and dry, climatic zones. Affected countries bordering on oceans have a way out of the shortage: desalination of seawater. Worldwide, more than 20,000 seawater desalination plants supply millions of people, plus animals, plants and the adjacent economy with drinking water. Countries in North Africa and Middle East are particularly dependent on this form of freshwater production. The high standard of living on the Arabian Peninsula, for example in Saudi Arabia, the United Arab Emirates, Qatar or Oman, would not be possible without the abundant freshwater extracted from the sea.

Several process technologies are available for seawater desalination. After multi-stage flash evaporation, in which the fresh water is extracted by means of heating and condensation, desalination plants have become established that operate on the principle of reverse osmosis. In this process, saltwater taken from the sea is forced under high pressure through special membranes designed to allow water molecules to pass through, but not larger molecules. The process involves several stages, requiring special mixing systems such as those developed and built by INVENT.

One of the largest seawater desalination plants using INVENT technology is located in the Sultanate of Oman. This seawater desalination plant is located in the north of the oil and gas-rich state, in Al-Ghubra, a suburb of the capital Muscat. The plant has been operating since 2016 and enables the extraction of 191,000 cubic meters of drinking water per day. In operation are 32 HYPERCLASSIC^®– and two CYBERPITCH^®-Mixers.

The mixers are integrated in the flocculation process, which serves to separate the finest solid particles. The HYPERCLASSIC^®-Mixers with their hyperboloid-shaped mixer bodies ensure particularly gentle suspension and homogenization of the liquid in the flocculation tanks, while the two CYBERPITCH^®-Mixers are used for rapid homogenization in the neutralization tanks.

Sustainable seawater desalination will continue to gain in importance in the future, and with it the plants and components required for this purpose. In Al-Ghubra work is currently underway to expand the plant with a production capacity of an additional 300,000 cubic meters of water per day. INVENT will accompany the developments with know-how and commitment and provide innovative products.

For more information, contact our INVENT office in United Arab Emirates:

INVENT Middle East (FZE)
SAIF Office Z3-06
P.O. Box 121720 Sharjah
UAE

Aviko is building a completely new production facility for deep-frozen French fries and potato flakes in Poperinge. Once in full operation, it will process 175,000 tons of potatoes per year, which equates to a waste water flow of more than 2,500 m3/day. Veolia Water Technologies was chosen to construct the treatment plant so that the heavily polluted water – the chemical oxygen demand reaches 26 tons per day – can be discharged and reused.

The wastewater from the potato processing industry has traditionally been difficult to manage. With a high starch content, non-negligible levels of fat from the fryer and a generally high concentration of nitrogen and phosphorus, wastewater treatment poses a complex problem. But the very strict discharge standards in Poperinge, with a maximum of 1 mg total phosphorus, complicate matters made, as well as Aviko’s desire to realize as compact a system as possible. „The ambitions for this project were very high,“ confirms Michel Danau, Sales Manager at Veolia. „Thanks to our shared expertise, we have achieved the goals.“

Compact but powerful

An area of ​​55 x 60 m. That was all Veolia had to ensure the treatment of the waste water. But the first important measure is implemented in advance, according to Sam Varga, project manager at Veolia. The waste water, which is rich in starch and fat, is kept separate during the entire production process. The main flow, namely the starchy water, goes straight to the treatment plant, where we separate the starch in a lamella separator and then separate the water, sludge and biogas using a UASB. Only then is the much smaller amount of fatty waste water, which has already undergone flotation treatment during production, fed into the main stream. In this way we avoid fats interfering with the anaerobic process.” The common effluents are treated according to a biological process based on nitrification/denitrification followed by ultrafiltration. What is special, however, is that both cases involve a double procedure. “We not only rely on pre- and post-nitrification/denitrification, but also supply two MBR (membrane bioreactors) that are connected in series. This is the only way to meet the stringent nitrogen and phosphorus requirements at such high flow rates.

The focus is on recycling

The extensive purification and removal of phosphorus also paves the way for water to be reused in the production process. For this purpose, an RO unit was installed after the MBR. „In a first step, we can only feed back a limited part of the wastewater, but later we hope to increase this proportion even further,“ says Cor Koole, project manager at Aviko. „At the moment we are still reaching the limits of the wastewater standards with the reverse osmosis concentrate.“ However, Aviko and Veolia are considering other options for further using the various wastewaters. “In consultation with the city of Poperinge, we have set up a buffer tank where we collect rainwater and our waste water. These waters can be used by local sports associations and some farmers to irrigate pitches and fields. And of course we also produce biogas in the biogas treatment plant, which we can use to supply our boilers.”

For people and the environment

To ensure the ergonomics of the operators and the comfort of local residents, the company has also invested heavily in ventilation and insulation. „All sludge tanks are installed indoors and all rooms are equipped with ventilation, extraction and exhaust air treatment,“ says Danau. “Rooms that are more prone to odor nuisance are delimited with airlocks and particular attention has been paid to sound insulation in the pump rooms. These aspects are often neglected, but the advantage of a new plant is that they can be integrated as early as the design phase.”

Text (German original) written by: Veolia Water Technologies Belgium

In recent years, the HYPERCLASSIC^®-Mixing and Aeration Systems have been developed into complete solutions for the industrial and municipal wastewater treatment. The characteristics of a mixer and those of an aerator are uniquely combined by the HYPERCLASSIC^®-Mixing and Aeration System.

A recent example is the company Ajinomoto Omnichem in Belgium, leader in pharmaceutical ingredients and intermediates. The cooperation between Ajinomoto and INVENT began already in 1998, when two HYPERCLASSIC^®-Mixing and Aeration Systems were initially installed in Balen and another ten in Wetteren. After these functioned to complete satisfaction, the plant in Balen was extended by five additional machines. After 20 years of reliable service the first two systems were replaced by two of the latest generation in 2020. The mixing and aeration systems in Balen and Wetteren provide mixing and aeration for COD removal and nitrification. Even with a low oxygen demand, a sedimentation-free operation can be ensured. The oxygen content remains homogeneous throughout the basin due to the generated flow.

The objective of low-maintenance, yet energy-efficient mixing and aeration, could be achieved with INVENT’s HYPERCLASSIC^®-Mixing and Aeration Systems in both plants of Ajinomoto Omnichem.

INVENT offers you optimized solutions for the respective process. Learn more about the use in the pharmaceutical industry here!

The wastewater treatment plant in Dordrecht, Netherlands, relies on INVENT’s hyperboloid technology. Back in 2005, 22 HYPERCLASSIC^®-Mixers were installed at the municipal wastewater treatment plant. After 16 years of successful operation, they were replaced by even more energy-efficient mixers of the 7th generation in 2021. This is not an exception: A large number of wastewater treatment plants that INVENT has equipped since the mid-1990s follow the example of the wwtp Dordrecht and continue to rely on the Hyperboloid-Mixers.

Thanks to their low energy consumption and high reliability, INVENT and the HYPERCLASSIC^®-Mixer became well-known among Dutch water association 25 years ago. Since then, more than 700 of the unique hyperboloid mixers have been delivered throughout the Netherlands for the mixing of municipal wastewater. Until today, the HYPERCLASSIC^®-Mixer is the most widespread vertical mixer.

Abstract: At 50 years, the Clean Water Act (CWA) has directly and indirectly benefited not only our planet but also our citizens and economy. While innumerable people and programs have contributed to the CWA’s success, the collaboration among stakeholders in our industry and communities has solidified it. Each group of stakeholders, including public officials and employees who manage and operate wastewater treatment facility facilities (WWTFs), regulators, funding agencies, contractors, equipment suppliers, researchers, trainers, and consultants, have contributed to maintaining and improving water quality. The evaluation, design, construction, and operation of the Warren, Rhode Island WWTF upgrade exemplifies how stakeholders throughout the wastewater industry can effectively collaborate to improve water quality and serve our communities.

Text by: Jon Himlan, PE, Woodard & Curran and Paul Dombrowski, PE, BCEE, F.WEF, Woodard & Curran

Copyright: Journal of the New England Water Environment Association