The design and operation of wastewater treatment systems for single houses, farms, hotels, leisure centres, small communities and small businesses are a challenge to wastewater engineers. In this paper, a pilot-scale system comprising a vertically moving biofilm reactor (VMBR) followed by a stratified sand filter was constructed and its performance was evaluated. The vertically moving biofilm reactor was operated as a sequencing batch biofilm reactor (VMSBBR). The results show that the VMSBBR unit efficiently removed 94.8% of the filtered chemical oxygen demand (CODf) from a synthetic wastewater with the influent CODf of 1096 +/- 425 mg/l, leaving 45 +/- 16 mg/l CODf in the effluent, at an organic loading rate of 0.9 kg COD/m(3) day. After the system had been operated for 133 days, the removal efficiency of orthophosphate (PO4-P) reached 90%. A sand filter polished the effluent from the VMSBBR unit and reduced suspended solids (SS) to 4.4 mg/l and total bacterial by 3 log 10 units. The advantages of the treatment system studied for small wastewater flows include: (1) simple operation and maintenance-sludge was only disposed of once on Day 206 during the 7.5-month study period; clogging, which often happens in other attached-growth biofilm systems, did not take place; (2) efficient removal of COD and phosphorus; and (3) low-energy consumption-the electricity consumption was 4.6 kWH/population equivalent (p.e.) year, or 0.6 kWh/m(3) wastewater treated or 0.6 kWh/kg COD removed. (c) 2005 Elsevier Ltd. All rights reserved.