Papers by Keyword: Sequencing Batch Reactor (SBR)

Abstract: With inoculum sludge from a conventional activated sludge wastewater treatment plant, formation of aerobic granular sludge for simultaneous phosphorus and nitrogen removal was realized in a sequencing batch reactor by the selective pressure as a driving force. Selective pressure created by means of decreasing sedimentation time and increasing substrate loading enhanced the formation of aerobic granular sludge, which followed four consecutive stages: acclimation, granulation, growth and maturation. Under the condition that the substrate loading were increased to 500mg COD/(L•d) and 48mg NH₄ ⁺-N/(L•d), the granules were the dominant sludge forms with most of diameter about 0.5–2.0 mm, a minimal settling velocity of 0.55 cm/s and a MLSS of 6800 mg/L after 120 days operation. The granules were composed of filamentous species with varying degrees of rod- and coccal-type bacteria. Microscopic examination revealed that granules microecosystem was more stable and should be less vulnerable to the changes of mixed liquor condition.

Abstract: Sustainable partial nitrification to nitrite has been proven difficult in treating low strength nitrogenous wastewater. Real-time aeration duration control was used to achieve efficient partial nitrification to nitrite in a sequencing batch reactor (SBR) to treat low strength domestic wastewater. Above 95% nitrite accumulation ratio was maintained for long-term operation at normal condition. Partial nitrification established by controlling aeration duration showed good performance and robustness even though some time encountering long-term extended aeration. Process control enhanced the successful accumulation of ammonia oxidizing bacteria (AOB) and washout of nitrite oxidizing bacteria (NOB).

Abstract: Wastewater discharges from livestock premises could cause serious environmental problems, and it difficult to remove effectively by using a single reactor due to the following characteristics such as high organic matter and high ammonia In this experiment by using the mixed processing mode of UASB plus SBR to study the pilotscale experiment for treatment of piggery wastewater, and investigate the reactor remove pollutants from wastewater at room temperature. After stable operation, the results of removal on COD, ammonia, SS were quite obvious, with the removal rate of 92, 90 and 95% respectively, the removal rate of TP was 80%, and the pH monitoring indicates that the reactor operate normally.

Abstract: Aerobic granular sludge (AGS) was cultivated successfully in a sequencing batch reactor (SBR), which has floc sludge as seeding sludge in synthetic wastewater. Removal efficiency in the reactor during the entire working period was investigated. Controlling strategy for filamentous bulking and the effect of a filamentous microorganism on granulation of sludge were discussed. The results showed that whether filamentous bulking occurred or not, there was little impact on the removal rate of phosphorus and ammonia nitrogen, which maintain about 90% and 95%, respectively. Increasing the hydrodynamic shear force has certain effects on the controlling of filamentous bulking. Declining C/N ratio, balancing nutrition in feed water can fundamentally solve the problem of filamentous bulking in the cultivation process of aerobic granular sludge.

Abstract: A sequencing batch reactor was employed to treat ammonia wastewater, the pH, DO and OUR were adopted to monitor the start of short-cut nitrification. The results showed that the start of short-cut nitrification was achieved in 31days, ammonia consumption rate was higher than 90% and nitrite accumulation rate was higher than 85%, when pH, DO and OUR were applied to monitor and determine the aeration time, under the condition of temperature was 30°C. With ammonia shock loading conditions, OUR curve couldn’t indicate the end of short-cut nitrification exactly. But real-time control using pH and DO could achieve a stable shortcut nitrification under steady stage and ammonia load shocking stage.

Abstract: This paper summarizes the function of styrene-butadiene rubber (SBR) in cement-based materials, focusing on the achievements of the authors in recent years. The effect of SBR on the properties of cement mortar is introduced, i.e. the workability of fresh mortar such as the water-reduction and water-retention effects of SBR, the mechanical properties of hardened mortar such as the tensile bond strength, flexural and compressive strengths, flexibility and anti-impacting capacity, the waterproofness such as the capillary water adsorption and anti-penetration capacity, the microstructure such as the matrix structure and interface structure, and the cement hydration such as the calcium silicate hydrates, calcium aluminate hydrates and polymerization of [SiO₄]^4- tetrahedron.

Abstract: In this study, rubber blend of natural rubber (NR) and styrene butadiene rubber (SBR) at 80/20 NR/SBR was reinforced with nanosilica (nSiO₂) and polystyrene-encapsulated nanosilica (PS-nSiO₂) in the latex state. The latex of PS-nSiO₂ was synthesized by in situ differential microemulsion polymerization using sodium dodecyl sulfate and azobisisobutyronitrile as the surfactant and initiator, respectively. The nanoparticles at the amount of 0.1, 0.2, 0.3 and 0.4 parts per hundred of rubber (based on dry weight of nSiO₂) were dispersed in the rubber blend compound and subsequently cured at 80°C for 3 h to prepare rubber nanocomposites. Using this technique, nanoparticles could be well dispersed in the rubber matrix. The influences of the nSiO₂ and PS-nSiO₂ on the mechanical and thermal properties of the resulting nanocomposites were quantified and compared. It is found that the tensile properties and thermal stability of the rubber blends were improved with the appropriate amounts of the nanofillers. However, the PS-nSiO₂ exhibited reinforcing efficiency superior to nSiO₂ with the same nSiO₂ content due to the stronger rubber-filler interfacial adhesion.

Abstract: In this paper, Cost-effectiveness of various straw pulp wastewater treatment technologies were compared in detail, moreover the separate and combined process of Coagulation Sedimentation, Anaerobic Baffled Reactor, Sequencing Batch Reactor and Biological Aerated Filter processes were researched. The test result has showed that when addition dosage of PAM and PAC is 4mg/L and 80mg/L in Coagulation Sedimentation separately, and ABR HRT is 10h, the biodegradability of the straw wastewater increased from 0.25 after pretreatment to about 0.45. As the best SBR HRT is 8h, the COD_cr removal rate was about 62%, the BOD₅ removal rate was 70.7% averagely, and the treatment effectiveness is steady correspondingly. But in combined process, the COD_cr removal rate of SBR unit is significantly increased to 78%, the COD_cr removal rate of whole system is higher than 90%. Finally, the BAF has been applied to the advanced treatment on outwater of two biological treatment. The experimental results show that there is a good efficiency on the advanced treatment of the using the method, the COD_cr of outwater is 78 mg/L, the BOD₅ is 28 mg/L, the chroma is 32 times, the SS is 38 mg/L, and the treated water not only meets the state's new discharge standards (GB3544-2008), but also satisfies the requirements of reuse water, and the cost of whole treatment is only RMB 1.80 yuan / m³ wastewater.

Abstract: Aerobic granules were cultivated in the sequencing batch reactor at 15-25°C, pH 7.0 ± 0.1. Settling time decreased from 5 minutes to 1 minute gradually. As increasing the chemical oxygen demand (COD) and NH₃-N in influent, COD removal efficiency and mixed liquid suspended solids of the reactor increased. Sludge volume index decreased continuously for a few days and then stabilized at 22 ml g^-1. Selective pressure induced by settling velocity was proved to play a crucial role in activated sludge granulation. Based on the continuously measured data, the granulation process was divided into three phases, granules namely initiating, developing and maturating.

Abstract: Mechanical and vulcanization behaviors of styrene-butadiene rubber(SBR)/N330 and SBR/N330/PBMCN nanocomposites were investigated via partial replacement of SBR with pyrophyllite based modified composite nanopowder(PBMCN), which were prepared by melt mixing procedure. Results show a fairly good dispersion of PBMCN in the SBR/N330/PBMCN composites characterized by field-emission scanning electron microscope (FESEM). Mechanical and vulcanization behaviors of the as-abtained pruducts were measured according to GB/T 528-2009 and GB/T 16584-1996, respectively. Near properties in tensile strength, elongation at break and vulcanization behaviors were observed in SBR/N330/PBMCN nanocomposites when SBR was partially replaced by PBMCN for 8% mass fraction. A possible reinforcement mechanism of PBMCN to SBR/N330/PBMCN nanocomposites is also dicussed based on the experiment.