Nutrient metabolism, mass balance, and microbial structure community in a novel denitrifying phosphorus removal system based on the utilizing rules of acetate and propionate

Abstract

The effect of acetate (HAc) and propionate (HPr) on denitrifying phosphorus removal (DPR) was evaluated in a novel two-sludge A 2 /O -MBBR (anaerobic/anoxic/oxicmoving bed biofilm reactor) system. Results showed that it was the carbon source transformation and utilization especially the composition of poly-β-hydroxyalkanoates (PHA) (mainly poly-βhydroxybutyrate (PHB) and poly-bhydroxyvalerate (PHV)) decided DPR performance, where the the co-exist of HAc and HPr promoted the optimal nitrogen (85.77%) and phosphorus (91.37%) removals. It facilitated the balance of PHB and PHV and removing 1mg NO3 -(PO4 3-) consumed 3. 04 -4.25 (6.84 -9.82) mgPHA, where approximately 40 -45% carbon source was saved. Mass balance revealed the main metabolic pathways of carbon (MAn,C (consumed amount in anaerobic stage) and

Enhancement of SBR’s treatment under organic shock load

“…Using the data from the batch experiments, the coefficients can be determined for zero order and first order by plotting Ce and Ln(Ce) respectively versus reaction time and the constant K equalsthe slope of the straight line. For Ci ranging from 355.68 mg/L to 1019.20 mg/L COD decomposition follows a first order reaction with a reaction rate constant, K = 0.59 h -1 , this value is very close to the value obtained by Turgay et al [36], and from 1104.13 mg/L to 1515.36 mg/L the reaction was zero order with a reaction rate constant, K = 216.1 mg/L.hr as shown in figure 4, and the experimental results and the output from equations ( 1), (8), and ( 13) are shown in figure 5. DO concentration increased from 0.3 mg/L to 0.6 mg/L after the first cycle of shock load and it continued to rise at a slow rate until it reached 0.8 mg/L after the eighth cycle.…”

“…The SBR is a fill-and-draw activated sludge system in which a single batch reactor can achieve equalization, aeration, and clarification processes, this method of biological treatment offers a powerful system, uncomplicated operation, and great adaptability in processes [5]. Despite the many advantages of this system, it still suffers from some problems, such as shock loads, the reactor's effectiveness was found to be relatively low in case of shock loading conditions [6,7] however, by providing appropriate levels of organic loading rates (OLRs), the biological wastewater treatment system is stimulated to maintain a diverse microbial community and promote efficient processes for converting nitrate and removing phosphorus [8]. On the other side, fluctuations in OLRs frequently align with ineffective removal of conventional pollutants, and emerging contaminants in municipal wastewater [9,10] so, the problem of shock organic loads still not fully understood and has attracted increasing concern worldwide, and many studies have been performed to study the effect of high organic loads and changes that occur in the composition of wastewater on the SBR system [11,12].…”