ABSTRACT It is not easy to find a solution which allows good management of sludge at reasonable costs for small wastewater treatment plants using the activated sludge process in extended aeration, which are common in France. Normal sludge drying beds are very expensive in terms of operational costs, their use is more and more being abandoned in favour of direct agricultural use of the liquid sludge. However, this solution, although satisfactory, cannot be chosen in all cases and often requires the construction of large storage tanks at high costs. A literature survey had shown that planting reeds on drying beds with sufficiently high free boards could be an interesting solution which combines both low investment and operational costs. A trial has been started in summer 1989 in France, using three experimental beds of 20 m2 each. Two beds are designed in the traditional way, one of them is planted and the other one is an unplanted control bed. The third bed is also planted, but Bioterra blocks are used for drainage and aeration from below. In six months the planted beds have received about 15 kg of dry matter m–2 and the control bed has received 6.5 kg of dry matter m–2 during the three and a half winter months.