NSI news – Water mission critical in the energy transition

Pre-treatment improvement suggestions
A typical treatment plant facility consists of several systems which are interconnected. The effect of performing an action at the pre-treatment stage can impact the biological and membrane stage. An important step to take is asking a process engineer to check your current system performance, or for new plants, review once again the design considerations. Possible savings can be achieved with smarter dosing of coagulation/flocculation, or dosing based on the actual pollution. Or, enhance the DAF performance to reduce the load to the biological process and thus reduce the energy consumption for aeration.

Biological treatment
In general, the monitoring of our aeration system is the first step to understand the high amount of energy. A potential solution could be changing existing biological designs into more energy efficient designs, like the BIOCTOR-FlooBed for industrial and municipal applications to improve the kWh/pollution. Or, to improve the blower efficiency, a blower performance test can identify energy and efficiency savings by utilizing our Riventa FREEFLOW portable pump testing system. In some cases, wastewater of industrial sites is still very hot. To keep thermal energy in the wastewater treatment plant or use it for other industrial processes, heating up a pipeline with hot wastewater can be an effective way to investigate for a smart heat balance in the factory.

Between 75% and 90% of all ammonia produced worldwide goes toward making fertilizer. In addition, the world’s food manufacturing relies on ammonia fertilizer. However, most of the world’s ammonia is currently produced using fossil fuel energy. A great energy reduction and CO2 contribution can be made as a country, but also locally, to recover ammonia from waste streams.

Many industries and communal water boards have to deal with the nitrogen present in their waste streams. Instead of releasing the nitrogen in the air via biological nitrification-denitrification process commonly used in wastewater treatment, technology such as ByoFlex can remove ammonia from water and produce ammonium sulfate at the same time. Ammonium sulphate can be sold to local farmers or agriculture industries as a replacement to the artificial fertilizers.

In this way, there’s a potential energy reduction possible within the complete supply chain by avoiding the use of synthetic fertilizers, meaning no manufacturing and transportation takes place to the industrial site or farm. Direct energy saving is achieved as the waste stream is not treated via a conventional biological treatment, but with an ammonia stripping technology saving footprint. With the recovering of ammonia of waste streams, the circular economy is being put into practice.

Many industries such as slaughterhouses, confectionary, protein processing industries, etc. are producing wastewater streams with high fat content. When removed and processed further, the fat has a high value as it can be used as biofuel, co-substrate for anaerobic digestion, etc. For example, a fat recovery solution (AECO-FAT) was put into operation in 2020 at one of the largest poultry slaughterhouses in the Netherlands. AECO-FAT first collects the fatty sludge by a dissolved air flotation unit (DAF), and then extracts the highly pure fat (purity>95%) via disconnection and three-phase separation.

With a slaughtering capacity of around 250.000 chickens per day, this Dutch slaughterhouse recovers around 1 ton of chicken fat per day, achieving payback period of 2-3 years. The recovered fat can not only be used as a heating fuel on site to save on their energy bill, but also sold as commodities for an increasing price (lately 1200 EUR/ton!).

Ask pump and blower operators about the efficiency of their equipment, and the truth is that most don’t know. The pumps, for example, might often be described as ‘working fine’ and ‘doing their job’, but is that, now more than ever, a strategy? The opportunity to truly maintain, protect and optimize assets is here and now, with a shorter return on investment (ROI) than ever.

The cost of solving asset management challenges is on a much smaller scale than most companies imagine. To test the pumps, Riventa is using the thermodynamic measurement technique to measure suction and discharge pressures either side of the pump, differential temperature, and motor input power. These measurements enabled us to calculate differential head across the pump, hydraulic efficiency, and volumetric flow. Energy savings of around 25% or more are results measured from the Riventa service.

A way out of the energy production crisis and CO2 reduction requirements is the anaerobic digestion of wastewater. The solution has been widely implemented, but it was never seen as the next big renewable. Anaerobic treatment systems are based on a biological process operated and controlled under anaerobic conditions that effectively treat COD, BOD, and VSS while producing biogas and very little biomass (without oxygen). Which anaerobic solutions are applicable to generate energy out of wastewater?

• The Econvert-UASB® has a proven track record for decades. The robust configuration enables the handling of large varieties in both volume and composition. A UASB reactor is the most widely used anaerobic process for industrial wastewater treatment. In a UASB reactor, anaerobic sludge in the form of granules is suspended in the bottom of the reactor and the flow of wastewater is upward through the sludge blanket.
• Econvert-EGSB® is an optimised compromise, combining a small footprint with few internals. The unique settling system of the reactor has proven to retain solids also in high flow. The EGSB design is appropriate for low strength soluble wastewaters. An Expanded Granular Sludge Bed (EGSB) reactor is a variant of the upflow anaerobic sludge blanket digestion (UASB).
• Econvert-IR®, the high performer. Designed to create the ideal process conditions, the two-stage settling system enables internal recirculation. Due to this, high COD concentrations can be treated, and optimum biological conditions are ensured. The internal and external recirculation provide optimum dilution. It has patented mixing chambers to avoid overloading of the bacteria.
• Econvert-Dsulph® is the perfect blend of biology and chemistry. Biogas typically contains H2 S, a component harmful to you and your equipment. This desulphurisation unit combines the chemical absorption of H2 S in the scrubber with the biological recovery of elemental sulphur in the bioreactor.

“To measure is to know”, a saying which, in times of an energy and water crisis and transitions, is still a valuable thing to say. To reduce the life-cycle cost of your plant and extend the lifetime, we provide complete management of your installation through 24/7 monitoring. Our i-MONITORING & program is a preventive method to control the number of installation issues.

Your installation will be monitored 24/7 with real-time access to your system. Our i-MONITORING dashboard is the connector and integrator of our complete digital solutions offering.

This allows our customers to use one single platform to access the installation and information regarding their operations and plant (performance), and to perform certain actions such as adding documents or ordering parts.

Another method to understand (and reduce) your carbon footprint is executing a life cycle assessment (LCA) by one of our Nijhuis Saur Industries and sister company engineers.