What is the difference between horizontal flow and vertical flow?
Horizontal flow reed beds work particularly well for low strength effluents, or effluents that have been pre-treated. Whilst not effective in reducing ammonia they will almost always reduce BOD (Biochemical Oxygen Demand) and SS (Suspended Solids) levels. They are particularly useful in converting nitrates into nitrogen gas, which completes the nitrogen cycle. An example of particularly effective use of the horizontal flow would be to treat the discharge from a sewage treatment plant, which fails to meet the discharge standard. Vertical flow reed-bed systems are much more effective than horizontal flow reed-beds in reducing BOD and SS levels and also in eliminating smells and reducing ammonia levels. They can be considerably smaller and will also cope with much stronger effluents. The two styles of system, horizontal and vertical, can be combined for the full treatment of domestic sewage, dirty water and sludge. How does the process work? Effluent is first fed into a septic tank to rem
