The estimation of per capita loadings of domestic wastewater in Tehran

The amount of wastewater characteristics loading is one of the main parameters in the design of wastewater collectionand treatment systems. the generation per capita per day (gpcd) of wastewater characteristics was estimated byanalyzing the monthly data of nine wastewater treatment plants in tehran, capital city of iran. gpcd values werecalculated from measured collected wastewater flow, the population and concentration data. the results indicated thevalues of 32.96 ± 1.91, 49.25 ± 2.49, 37.31 ± 2.44, 6.77 ± 0.53, 1.96 ± 0.11, 92.23 ± 5.68, 2.07 ± 0.39 and 128.96 ± 6.69 g/d.capof gpcd for bod5, cod, tss, tkn, p, tds, on and ts, respectively, for tehran’s wastewater. the per capita estimated forthe wastewater production and treatment were determined to be 186.06 ± 7.85 and 136.72 ± 5.43 l/d.cap, respectively. itis estimated that about 504 m3/d and 346 m3/d of sludge, will be produced and waste as excrement raw sludge,respectively, in tehran. simple regression models were presented the relationships such as the change of collected andtreated wastewater with population and changes of gpcd parameters with each other. it was revealed that the tehran’swastewater may be classified as highly degradable, but during recent decades its biodegradability index (bi) has beenreduced up to 15%. the new suggested revised per capita parameters can be used for design purposes in tehran, andpossibly, in areas with similar characteristics, substituting the classical values obtained from foreign textbooks. thesevalues could help in designing more accurate treatment systems and may lower the required capacity for the treatmentof wastewater up to 40% in tehran.