Study on Quantity and Quality of Hospital Wastewater in Tehran City in 1385

Different types of sewage including hospital sewage are important especially from health point of view because of pathogenic organisms due to sewage and other risk factors. In this research, the quantity and quality of hospitals’ sewages in selected Tehran hospitals are studied. 14 similar with same basis hospitals are selected, general, specialized and highly specialized hospitals and sanatoriums. from each selected centre, two series of sampling under the form of instantly and mixed forms are taken and qualitative parameters such as biochemical oxygen demand (BOD5), chemical oxygen demand (COD), potential of Hydrogen (pH), electrical conductivity (EC), total suspended solid (TSS), and total dissolved solid (TDS) were studied. This research results show that average of BOD5, COD, TSS, TDS, pH and EC in mix sampling of refined sewage were 42, 86, 54, 768, 7.1, 768 mg/lit and in mix sampling of non-refined sewage was 320, 507, 380, 743, 6.97 and 561 mg/lit accordingly. Minimum and maximum of BOD5 in mix sampling for refined sewage was equal to 25 and 68, and for non-refined sewage was equal to 281 and 381. Minimum and maximum of COD in mix sampling for refined sewage was equal to 37 and 113, and for non-refined sewage equal was 419 and 687. Minimum and maximum of TSS in mix sampling for refined sewage equal was 28 and 82, and for non-refined sewage equal 300 and 1309. Minimum and maximum of TDS in mix sampling for refined sewage was equal to 626 and 857, and for non-refined sewage was equal to 469 and 695. Minimum and maximum of pH in mix sampling for refined sewage was equal to 6.5 and 7.8, and for non-refined sewage was equal to 5.9 and 7.8. Minimum and maximum of EC in mix sampling for refined sewage was equal to 398 and 1483, and for non-refined sewage was equal to 481 and 928. In this side average hospital sewage's flow in unit research for small hospitals with maximum 400 beds, is calculated 1300 lit/bed/day (l/b/d) and for great hospital with up to1000 beds, is calculated 750 l/b/d.Findings of this research showed, that changes of BOD5 rate with number of hospital section have direct relation and quantities of qualitative parameters in hospital sewage with a little increase is approximately equivalent of those rate in urban sewage. Moreover, findings of research of instant sampling in comparison with mix sampling showed credit and recommendation to use mix sampling.