With our combination vertical and horizontal flow reed-bed systems we can consistently achieve a quality better than 10 mg/l for BOD (Biochemical Oxygen Demand) and SS (Suspended Solids), and better than 3 mg/l for Ammoniacal Nitrogen. Frequently it is better than 5 : 5 : 1 respectively.
![](https://www.reedbeds.co.uk/media/reed-beds-faq-19.jpg)