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:

Nijhuis 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 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 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 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:

Nijhuis Flotation 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 flotation fat recovery system 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 dosing control

To effectively remove solids and COD from wastewater with flocculation-flotation systems, chemical dosing is required. Iron chloride is added to coagulate the water into small particles. By neutralizing and adding a polymer, these small particles grow into larger flocs. These flocs can be separated by using a dissolved air flotation system (DAF).

However, the chemical dosage is not designed on the real-time fluctuations of COD in the wastewater. In practice the COD load in the balance tank increases during production hours and decreases during cleaning. By using an intelligent chemical dosing control, the costs for coagulation, flocculation and neutralization (FeCl3, NaOH and polymer) can be substantially reduced.

Nijhuis has designed the “i-DOSE” system to comply with the real-time dosing process and reduce wastewater chemical consumption costs.

Nijhuis Intelligent High Rate Flotation Unit

The “Intelligent High Rate Flotation Unit” is a SMART solution that guarantees maximum and efficient solids removal, taking pretreatment technology to the next level. Especially for the purification of sea and surface water, pre-treatment solutions have to be compact, robust, stable and modular at the same time.

The next generation of flotation units is developed by a multidisciplinary team at Nijhuis Industries, combining the civil and hydraulic engineering of Nijhuis Industries UK & Ireland and innovative wastewater technology from Nijhuis Water Technology. The solution is based on smart modular sections of 1,500 m3 /h, each incorporating innovative and efficient coagulation, flocculation and flotation functionality ensuring a compact design and lowering the environmental footprint.

Nijhuis AecomixTM-DGF

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.

Nijhuis Intelligent Containerized Flotation

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.