Raceways/Flow-through systems

A raceway, also known as a flow-through system, can be described as an artificial channel. Water flows from a higher located point down to a lower point and then flows back into rivers or the sea, with or without water treatment. Other than with recirculation systems a flow-through system can get organically certified, even though raceways without water treatment discharge wastewater into the natural environment which can have negative impacts due to the faecal matter entering the natural water system. This can lead to a higher risk of spreading diseases. Water treatment can reduce the impact on the natural environment. In raceways there is better control of negative effects compared to net pens. Disadvantages are the high use of water, discharge of wastewater in surface water and the chance of spreading diseases.