Study on Effect of Hydrolysate on Denitrification Rate

The effect of hydrolysate on the denitrification rate was studied in a sequencing batch reactor.Four series of tests using hydrolysate dosages of 0,10,20 and 30 mg/L(calculated as TOC) were conducted at 21 to 23 ℃.The results show that the hydrolysate can significantly improve denitrifica-tion rate of denitrifiers.The average denitrification rate and carbon consumption rate are increased with the increase of hydrolysate dosage in the first denitrification stage.When the hydrolysate dosage is 30 mg/L,the average denitrification rate in the first stage is 0.367 mgNO 3--N/(mgVSS.d),being 1.83 times of that without hydrolysate dosage,and the average carbon consumption rate is 0.713 mgTOC/(mgVSS.d),being twice of that without hydrolysate dosage.Organic carbon in the hydrolysate can be divided into two parts which are easily and hardly used by denitrifiers,and the higher the hydrolysate dosage is,the greater the easily uptaken organic carbon content is.When the hydrolysate dosage is 30mg/L,the organic carbon which can be used by denitrifiers is 75.7%.