Retrofitting Forced Bed Aeration into existing reed beds

Forced Bed Aeration

Forced bed aeration in reed bed system saves money and educates visitors The National Botanic Garden of Wales last summer introduced a new enhancement to its wastewater recycling system. History of recycling wastewater Since the garden opened, it has recycled its wastewater using reed bed technology, which allows bacteria to break down solids into liquid, according to the garden's Web site. This recycling system, installed around 1998, included a settlement tank, anaerobic digester, closed aerobic tank, and clarifier. It was capable of handling flows from up to 4000 people per day, said Clive Edwards, operations and facilities manager at the National Botanic Garden of Wales. "Although state-of-the-art in its day, the old system was very reliant on flow pumps and aeration pumps, and consequently expensive to run," Edwards said. The system used around 10 kilowatts of electricity per hour at a cost of $12,850 (£8000) each year, he explained. "The need to desludge the system after 10 years led to a discussion on its effectiveness, "Edwards said. "In the light of advances in technology, it was decided to upgrade the system." Installing a new and improved system In August, the gardens installed technology known as forced bed aeration within the reed beds, removing the old system and its aeration tanks. The new system feeds directly into a larger external reed bed system, Edwards said. ARM Reed Beds (Staffordshire, England) installed a 128 m2 saturated vertical flow aerated reed bed system designed to handle peak flows of 48 m3/d, with average flow rates of 18 m3/d, said Clodagh Murphy, researcher at ARM Ltd. (Rugeley, England). "We basically retrofitted the forced bed aeration system into the [existing reed bed]," Murphy said. To do this, the company cleaned out the existing bed, washed the gravel at the bottom, placed aeration lines below the bed, and changed the distribution system....   Read More...