Proceedings

Decentralised sanitation can be useful when point sources contain specific contaminations. This makes it possible to design cost effective and dedicated treatment options and might generate extra value due to integration at the specific location. Reinier de Graaf Hospital in Delft has adopted a waste- and wastewater concept (denoted as Pharmafilter) which has two primary components: increasing efficiency and health security in a hospital and an innovative wastewater treatment. Energy is recovered, the quantity of waste is considerably reduced and the wastewater is converted into process water without any trace of micro-pollutants. The benefits for patient and nursing staff are Improvement of hygiene and efficiency of hospital processes by using single-use disposables as bedpans resulting in a positive financial case and less cross contamination in the hospital by reducing the number of contact moments between staff and contaminated waste. The hygienic and medical disposables together with kitchen refuse are removed by means of decentralised shredders and the existing hospital sewerage system. The solids fraction in the waste is fed to an anaerobic thermophilic digester and the liquid fraction to a treatment plant. The latter consist of a membrane bioreactor, a high flux ozonisation and a granular activated carbon treatment for optimal removal of micro pollutants such as medicines, X-ray fluids and hormone disturbing substances. The concept was tested in 2008 as a proof-of-principle for the wastewater treatment and digestion component of the total Pharmafilter concept. The digestion of amongst others bioplastics under thermophilic conditions was possible and also analyses of the water phase showed complete removal of all tested micro-pollutants. On basis of these tests a full-scale installation has been built which is since 2010 operational in Delft. For the MBR a novel tubular ultrafiltration module with down-flow air-scouring was used. This unit showed less fouling and lower energy need then a parallel operated conventional tubular membrane unit. Also the full scale system showed > 99.99 % removal of X-ray contrast fluids, hormone disturbing substances measured as ER-, AR- en GR-Calux and for the traditional compounds such as nitrogen and BOD/COD. Also a full hygienisation was obtained, currently reuse of heat through heat exchangers as well as the water itself are investigated. The costs for decentralised water treatment are compensated by the costs savings related to hospital management, resulting in a net-cost reduction for hospitals upon implementation of the system.

Keywords Hospital waste water; micro pollutants; membrane bioreactor; ozone; activated carbon.