The local communities of Mandra and Koutsocheros are part of the D.E. Valley of the Municipality of Larissa, where there are no infrastructures for the collection and treatment of waste water and their disposal is done in absorbent cesspools. Due to the low permeability of the soil and the small depth of the cesspits, problems of soil pollution often arise and require frequent evacuation, resulting in significant economic costs and environmental nuisances from tank-evacuation vehicles. Some rainwater networks in these settlements are often used illegally for the drainage of waste water which eventually end up in nearby ditches creating an immediate pollution problem.With this operation, sewage systems have been built for urban waste water with pumping stations and a common ERL for T.K. Mandras and Koutsocheros. The internal network of the two settlements of Mandra and Koutsocheros is a total length of 4,900,00 m and diameter Φ200. The internal drainage system of Koutsocheros ends at the pumping station A/S-1 and then the sewage with a depressive pipeline length of 2120,00 m and diameter Φ110 is transferred to the pumping station A/S-2. The internal drainage system of Mandra ends at the pumping station A/S-2. The sewage of Mandra and Koutsocheros from the pumping station RS-2 with a depressive pipeline 510,00 m long and diameter Φ125 is led to the common ERL. The method of processing has been chosen as the adhesive biomass with bio-rotors (pre-manufactured compact unit) followed by tertiary treatment with hyperfiltration membranes and disinfection. The treated waste water will be disposed of by re-use for the purpose of irrigation in accordance with Joint Ministerial Decree 145116/2011 in the soil by irrigation of plant vegetation (planting of trees) on an adjacent SPD field with a Slow Rate System (SRS).