Based on extensive research on calcium filters we have developed a new wastewater treatment technique for households unconnected to domestic treatment plants. The system provides improved durability, better Phosphorus removal capacity and decreased costs for the property owner. The concept is based on a combination of a drainage sand bed and a Calcium filter bed. The technical solution strongly reduces the risk for clogging of drainage beds. The life-span of the drainage bed is doubled. The Calcium filter bed constitutes the second step of the treatment system and is now installed with reduced costs, since research carried out in co-operation with the Swedish Environmental Research Institute show that one of the low-cost Calcium materials provides high and durable Phosphorus retention capacity. We focus on installations for 5-100 households, but also offer systems for single households.