reed bed treatment systems

Reed Bed Treatment Systems Reed bed treatment systems are self-contained, artificially engineered, wetland ecosystems. They are designed to optimise the microbiological, chemical and physical processes naturally occurring in the wetland. Wetland plants, such as reeds, transfer atmospheric oxygen down through their roots in order to survive in waterlogged conditions. This creates both aerobic and anaerobic soil conditions, allowing extraordinary microbial species diversity to flourish. These bacteria and fungi can use organic pollutants as a food source, breaking down a wide range of organic chemical products. So, chemicals are not simply stored in the reed bed; they are actually degraded into harmless components. Other contaminants, such as metals, are transformed from a toxic, mobile state and fixed in the soil via complex chemical reactions. Soils adsorption capacity also provides a buffer for peak or shock effluent loads.

The complexity of microbial life and powerful reactions within the root zone of the soil based reed bed result in an extraordinary water cleaning capability. This capability is often far less constrained than in many chemical or physical wastewater treatment systems. At Oceans-ESU we have cultivated our own stock of robust and suitable plants of the species Phragmites australis for use in our wetlands systems. Other plant species are suitable too for certain applications, but our strain of Phragmites has proven to have the characteristics necessary for optimum treatment of contamination in a reed bed. The plants within the reed bed system have three main functions: They provide the means for secondary restructuring of the soil system. The very extensive root and rhizome system creates channels for the water to pass through and also keeps the soil open through the constant growth and die back of the root system. The roots of the aquatic plant introduce oxygen down into the body of soil, providing an environment where aerobic, or oxygen dependent, bacteria can thrive. Such bacteria are required for the effective breakdown of many types of compounds, and the plants allow them to thrive. The plants are capable of taking up a certain amount of nutrient from the wastewater themselves. "Groundwater remediation in Scotland"

"Our strain of Phragmites australis demonstrates impressive growth in industrial effluents" Development of the use of reed beds to treat high strength wastewaters from the food industry is another of the firm's ventures. Working with yeast manufacturers and sugar distilleries, the technology has been tested with liquid and slurry wastes of up to 35,000 mg/l BOD, achieving in excess of 90% removal over trial periods of just two years. Other works include the operation of two large coke oven wastewater treatment systems for steel works. Here the systems have been proven to be capable of dealing with ammonia loads in excess of 3,000 mg/l, achieving a consistent 90% reduction in load. Additionally removal of the cyanides, thiosulphates and PAH occurs.

Many suppliers of reed bed technology offer only gravel-based reed bed treatment systems, but we prefer to utilize the active treatment capabilities of soil to biologically treat effluents such as sewage, industrial wastewaters, run-off & leachates. Reed beds are suitable for treatment of organic contaminants, either natural or synthetic, and some inorganic contaminants are also withheld or converted to safe products within the substrate of the reed bed system. Some of the contaminants that may be familiar to you and that can be tackled in reed bed systems are as follows: Biological Oxygen Demand (BOD) Chemical Oxygen Demand (COD) Ammonia Heavy metals Solvents Suspended solids Organic petrochemical derivatives including diesel Phenol and phenolic compounds Pesticides Amines Sewage Faecal coliforms, bacterial contamination etc. Textile dyes …and many others! "Root Mass of Reeds"

Please contact us if you have a particular application or contaminant in mind. Return to Water Index