Game-changing solutions in waste and (waste)water

Innovations in water technology are vital to finding solutions to the challenges we face today: climate change, ageing infrastructure, urbanization, resource shortages, the economic and financial crisis, new emerging substances, the need for sustainable development and demographic changes. Our experienced Research and Development technologists are continuously working on the development of game-changing solutions for purifying (waste) water and recovering valuable resources. We perform a wide variety of tests executed in our state-of-the-art equipped laboratory often supported by pilot trials on-site.

Here are some exciting examples:

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Smart removal of medical residues at the source

At the beginning of 2019, a pilot was started in the Netherlands to remove medical residues from hospital wastewater in a smarter way. Nijhuis Industries, Van Remmen UV Technology, Water Authority Rijn en IJssel Water and Koningin Beatrix Hospital in Winterswijk will investigate whether wastewater can be treated more effectively and cost-effectively with a smart application of Ozone and UV technology. From the first week of January 2019, a yellow pilot container was available at the hospital, ie at the source until December 2019. Since January 2020, the container is located at the Winterswijk sewage treatment plant.

The aim is to improve water quality for humans and animals. Currently, all wastewater from hospitals goes through the sewer to sewage treatment plants, which purify this water before it ends up in the streams and rivers. However, this does not prevent that a part of the medical residues still ending up in surface water. A pre-purification can prevent this. In the pilot container, the hospital wastewater is treated with an integrated Ozone and UV treatment before it is discharged into the sewer. During this period, extensive research will be conducted into whether and how an approach at source / decentralized treatment in hospitals can be more effective and profitable.

More information (in Dutch)

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Creating the necessities of life with Circular Sanitation Hubs

Following the sixth Sustainable Development Goal of the United Nations, everyone should have access to clean drinking water and hygienic sanitation in 2030. To respond to this goal, Nijhuis Industries together with several partners (like Semilla Sanitation Hubs) has developed a cost-efficient solution with no or low environmental impacts, which not only processes human urine and faeces, but also recovers required nutrients.

Unique and decentralized solution

Nijhuis WASTE-TO-TASTE is a circular sanitation hub solution for Public Toilets, Hotels/Resorts, Plug and Play Villages, Rural Places/Developing Countries and Disaster Relief. The solution utilises advanced space technology and includes modular ‘plug-and-play’ technology building blocks such as grey, black and urine water treatment which collectively offer more than 30% in water savings. The completely self-sufficient solution turns waste (grey, black and yellow water) into taste (food & drinks) and continues the global trend towards a circular economy.

Nijhuis AECO-NAR - Ammonia Recovery

An award winning solution to recover ammonia from digestate or substrates from digestion. Instead of biological oxidation the recovered ammonia is turned into a bio-based fertilizer turning waste into value. The Nijhuis mission with this next level of ammonia recovery is ‘doing more with less’. The AECO-NAR has a proven ammonia removal efficiency of 80-90%, with the lowest energy consumption. Dilution of the substrate creates a higher biogas production by minimizing toxicity. Less additional co-substrates are required to mix the high ammonia substrates.


Several technologies claim effective removal of ammonia from digestate. However, all of these technologies consume a lot of energy and only oxidize the ammonia, without creating a valuable product. By removing ammonia, the treated water can be used for

  • diluting the substrate to enable more co substrates,
  • lowering the ammonium concentration of the substrate or
  • improving COD/N ratio of the centrate water

The AECO-NAR is an innovative and stable process which is anticipating today’s challenges in the market and producing ammonium sulphate, to maximize the value of digestate. The market potential for this biobased fertilizer varies per geographical location, but proves to be commercially very attractive.

The AECO-NAR is a proprietary chemical process based on the stripping of ammonia. The process is designed to treat digestate, or manure, and consists of a heat exchanger, a CO2 stripper tank, an ammonia stripper and a scrubber. In order to prevent clogging of the stripping column, pre-treatment of the digestate such as a cloth screen, screw press or centrifuge is required. In the CO2 stripper tank the liquid is heated up and fresh air is injected in to the liquid to strip CO2. A heat exchanger on the effluent flow reduces the heat requirement of the system.

This development is financially supported by:


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Nijhuis AECO-FAT - Fat Recovery

Industrial wastewaters with a high fat content are often treated by dissolved air flotation (DAF) to remove fat and solids before secondary (biological) treatment is applied. While fat is the predominant dry matter of the sludge, this valuable resource is currently not recovered. The AECO-FAT is a ROI based system dependant on the water, solids and fat concentration in the flotation sludge with several benefits such as:

  • No flotation sludge disposal cost.
  • Use DAF as a smart integrated solution to recover fat.
  • Robust and effective separation of water and sludge.
  • Generate biofuel and steam from wastewater.
  • Valuable fertilizer / feed to digester.
  • Clean wastewater and pay less on trade effluent charges.

This development is financially supported by:


Nijhuis i-DOSE system, Intelligent Wastewater Chemical Dosing

To effectively remove solids, COD, NO3-N and PO4-P from wastewater, chemical dosing units, pumps and systems are often applied and needed to comply with the effluent discharge requirements. However, a fixed chemical dosing for wastewater treatment is in general not sophisticated enough to handle the actual day-to-day fluctuations in the wastewater and this can cause additional chemical and energy costs.

For example for primary wastewater treatment, the COD load in the balance tank increases during production hours and decreases during cleaning. By using an intelligent wastewater chemical dosing system, costs for water treatment chemicals for coagulation, flocculation and neutralization can be substantially reduced. The wastewater process can deal more easily with fluctuations in pollution load.

About i-DOSE
Nijhuis Industries has designed the “i-DOSE” system to comply with this real-time control process for chemical treatment of wastewater, significantly reducing wastewater operational costs (e.g. chemicals, aeration, energy). The system also allows facilities to be operated at a maximum performance with reduced operator’s presence due to the intelligent dosing philosophy. As well as our existing and proven i-DOSE pre-treatment applications, i-DOSE can also be applied within secondary and tertiary water and wastewater treatments.

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Nijhuis High Rate i-DAF

Currently, efficient solid and phosphorus removal solutions for sea, surface, and wastewater are a major theme in the industrial and municipal water treatment markets. Additionaly, the rise of membrane filtration technology applications has presented companies with new challenges: to minimize costs (membranes and energy) and system failures.

The ‘High Rate i-DAF’ is a SMART solution that guarantees maximum and efficient solids removal, taking pre-treatment technology to the next level. Especially for the purification of sea and surface water above 1000 m3/hr / 25 MLD, pre-treatment solutions have to be compact, robust, stable and modular at the same time. The Dissolved Air Flotation technology (DAF) has proven to be very successful as a pre-treatment step. Nijhuis flotation systems have been developed since the 1970s and our units stand out as the best in their field.


  1. High quality membrane feed water due to robust and reliable removal of solids.
  2. Lower CAPEX (reduced civil costs and standardized production of material.
  3. Lower OPEX (reduced energy consumption and reduced sludge discharge)


The AECOMIXTM-DGF is a revolutionary and highly innovative solution, especially tailored for food & beverage plants treating wastewasters with high TSS and/or FOG. Additional benefits can be realized when the plant is designed to treat factory waste as well. The concept provides a single step process solution for different substrates with a high removal efficiency (of organic matter) of more than 95% on COD. Since the majority of removed organics is transferred into biogas, a much higher biogas volume is achieved in comparison to traditional routes.

In the event post-treatment is required, this step will be less intensive in comparison to the traditional method because more organics will already have been removed in the AECOMIXTM process. This results in a smaller footprint and less OPEX for polishing.

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Nijhuis Intelligent Containerized Flotation (ICF)

For decades the Nijhuis Water Technology Dissolved Air flotation unit has been known as the most robust and best DAF unit available on the market. However, in response to variations in industrial activity and customers’ requirements to quickly and efficiently relocate production facilities, Nijhuis has now redesigned their DAF concept. The result is an even more efficient system than before. Located within a high cube container, the revolutionary and innovative Intelligent Containerized (Flocculation)-Flotation system allows customers to achieve environmental compliance within a very limited time scale.

The Nijhuis Intelligent Dissolved Air Flotation (i-DAF) system is based on the Nijhuis innovative and intelligent aeration system (i-AIRATION) which forms fine air bubbles for the separation of particles.

Development of i-DAF is financially supported by OP-Oost the Netherlands
The operational program (OP) EFRO Oost-Nederland is a financially supported program of the provinces of Overijssel and Gelderland and is working on economical improvements to stimulate innovations and a low-carbon economy. The goal is that more companies from the East side of the Netherlands receive more revenue from new products.

Nijhuis Water Technology has been active for decades in the international market with its Dissolved Air Flotation (DAF) systems. Through continuous improvements, the DAF is realizing the highest worldwide performances, which has contributed to its leadership in this area.

The performance of the DAF system is at the moment so effective, that no performance perfection can be achieved through conventional improvement. Within this project, NWT wants to develop a new generate of DAF technology (intelligent Dissolved Air Flotation, i-DAF) by applying advanced simulation methods, making the system more intelligent and apply smart sludge dewatering, and is at least performing 10 – 20% better than the current DAF systems.

​Nijhuis ozone and advanced oxidation systems

Ozone and advanced oxidation processes have been successfully tested in wastewater treatment to remove difficult compounds. Nijhuis is therefore developing an ozone oxidation system for the removal of such compounds, focussing on the removal of recalcitrant COD (non-biodegradable organic compounds) and micropollutants (hormones, pesticides and medicines).

With the advanced oxidation process (AOP), the oxidation potential is increased through the addition of OH radicals. Due to the short lifetime of these radicals the local formation close to target compound is essential for a good efficiency. The Nijhuis ozone oxidation system can be applied both to treat the recalcitrant COD and micropollutants as well as to improve the biodegradability of the industrial and municipal wastewater.

This project is financially supported by MIT Oost

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