Model Nutrients Reduction Solutions In Near-Coast Touristic Areas

Pilot 3: Næstved, Denmark

05 March 2024
Technical details

The project tests nanobubbles as a new solution for wastewater treatment, particularly in cases of high organic load or variable demand.


Næstved, Denmark

The technology used in the pilot:

Vallensved WWTP is a small biological wastewater treatment plant (mechanical treatment, biological treatment with nitrification). The biological tank is aerated using a surface aeration because of the low tank dept. It is an energy expensive method for aeration and not very effective. The idea is to improve the efficiency of the plant, so it can treat more wastewater especially in period with high wastewater load. Bottom aeration is not a possibility, so the idea is to test nanobubble addition as a method to improve the aeration. A pilot plant has been established at Næstved Renseanlæg to evaluate the effectiveness of nano-bubble aeration in wastewater treatment. The pilot plant comprises three tanks, each with a maximum capacity of 1 m3, configured as Sequential Bio-Reactors.

About the pilot:

The pilot plant is situated at Næstved Renseanlæg and comprises three intermediate bulk container (IBC) tanks. These tanks collect raw wastewater from the main plant, while the treated wastewater is recycled back into the system. The primary concept involves utilizing a nanobubble generator for aerating a wastewater treatment biological tank, aiming to enhance oxygen transfer and increase the tank’s capacity. If the results are positive, the plan is to establish nano bubble generator as an external unit at smaller plant e.g., Vallensved (700 PE).

More information:

Read more about the project from the report “Technical preparation for wastewater treatment investments at BSR tourist destinations”.