Kinetic analysis of nitrifying biofilm growing on the rotating membrane disk

2001 ◽  
Vol 1 (4) ◽  
pp. 111-118
Author(s):  
K. Kimura ◽  
Y. Watanabe ◽  
S. Okabe ◽  
H. Satoh

The authors have proposed a novel water treatment process in which nitrifying bacteria are fixed on the surface of rotating membrane disks. This biofilm-membrane process can perform strict solid-liquid separation and oxidation of ammonia nitrogen simultaneously. In this research, applicability of the conventional biofilm model (assuming the biofilm structure to be flat, homogeneous and continuous) to analysis of the biofilm developing in the proposed process was examined. A long-term operation for culturing the active nitrifying biofilm was carried out prior to kinetic investigation. By cryosectioning of the biofilm and image analysis, the thickness of the biofilm was determined to be 87 μm. From this biofilm thickness and the result of the batch ammonia consumption test, the intrinsic zero-order ammonia consumption rate of the biofilm was estimated precisely to be 930 g/m3/h. Using these parameters, the ammonia concentration profile in the biofilm was calculated by the conventional model, and the applicability of the model was examined by comparing the calculated profile with the ones measured with a microelectrode. The calculated profile was very close to the measured ones, which indicated feasibility of the conventional model to the analysis of the biofilm grown in the proposed process. The studied biofilm actually had a simple, i.e. flat, homogeneous and continuous, structure due to membrane filtration. This was the reason why the conventional model could still be employed. In the analysis of the data dealing with low concentrations of ammonia, however, first-order kinetics should be used. The first-order ammonia consumption rate constant of the studied biofilm was estimated to be 808 h-1.

2007 ◽  
Vol 55 (8-9) ◽  
pp. 355-362 ◽  
Author(s):  
L.S. Downing ◽  
R. Nerenberg

We report on a novel process for total nitrogen (TN) removal, the hybrid membrane biofilm process (HMBP). The HMBP uses air-supplying hollow-fibre membranes inside an activated sludge tank, with suppressed aeration, to allow concurrent nitrification and denitrification. We hypothesised that a nitrifying biofilm would form on the membranes, and that the low bulk-liquid BOD concentrations would encourage heterotrophic denitrifying bacteria to grow in suspension. A nitrifying biofilm was initially established by supplying an influent ammonia concentration of 20 mgN/L. Subsequently, 120 mg/L acetate was added to the influent as BOD. With a bulk-liquid SRT of only 5 days, nitrification rates were 0.85 gN/m2 per day and the TN removal reached 75%. The biofilm thickness was approximately 500 μm. We used DGGE to obtain a microbial community fingerprint of suspended and attached growth, and prepared a clone library. The DGGE results, along with the clone library and operating data, suggest that nitrifying bacteria were primarily attached to the membranes, while heterotrophic bacteria were predominant in the bulk liquid. Our results demonstrate that the HMBP is effective for TN removal, achieving high levels of nitrification with a low bulk-liquid SRT and concurrently denitrifying with BOD as the sole electron donor.


2020 ◽  
Vol 81 (2) ◽  
pp. 309-320 ◽  
Author(s):  
Linan Zhang ◽  
Bei Long ◽  
Yuanyuan Cheng ◽  
Junfeng Wu ◽  
Binchao Zhang ◽  
...  

Abstract Autotrophic nitrifying granular sludge (ANGS) was cultivated by gradually decreasing the influent organics and adding exogenous nitrifying bacteria. Under the strategy, ANGS was domesticated within 36 days. Stability of the seed heterotrophic granules decreased significantly during conversion of organic wastewater to inorganic ammonia wastewater. Obvious granular breakage was observed during these days. However, the granular debris still had good settlement performance. With microbes gradually acclimated to the new environment, the debris provided a large number of carriers for the attached growth of the exogenous nitrifying bacteria, and they replaced the heterotrophic bacteria and became the dominant species. The domesticated ANGS showed good nitrification performance during the 37th to the 183rd day (ammonia nitrogen load between 0.28 and 0.29 kg/m3 · d). The removal rate of ammonia nitrogen was usually more than 95%, and nitrite accumulation rate was always larger than 50%. However, nitrification ability was gradually lost with the increase of the ammonia nitrogen load (0.3–0.64 kg/m3 · d) from the 184th day, and it almost approached the influent ammonia nitrogen at the 269th day. Interestingly, good structure stability of the ANGS was maintained during long-term operation, and the ANGS became smoother and denser at the end of the experiment.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 1995-1998 ◽  
Author(s):  
B. M. Peyton ◽  
W. G. Characklis

In predictive biofilm modeling, the detachment rate coefficient may be the most sensitive variable affecting both the predicted rate and the extent of biofilm accumulation. At steady state the detachment rate must be equal to the net growth rate in the biofilm. In systems where organic carbon is growth-limiting, the substrate carbon utilization rate determines the net biomass production rate and, therefore, the steady state biomass detachment rate. Detachment rates, first order with biofilm thickness, fit the experimental data well, but are not predictive since the coefficients must be determined experimentally.


2003 ◽  
Vol 48 (1) ◽  
pp. 191-198 ◽  
Author(s):  
T.K. Chen ◽  
C.H. Ni ◽  
J.N. Chen ◽  
J. Lin

The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention critical to achieving more efficiency for biological degradation of pollutant. Although it is a new technology, the MBR process has been applied for industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is high technology manufacturing. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N) is very difficult to meet the discharge limits. This research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 5 m3/day capacity of MBR pilot plant consisted of anoxic, aerobic and membrane bioreactor was installed for evaluation. The operation was continued for 150 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5 items, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification was also successfully achieved. Furthermore, the effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.


2005 ◽  
Vol 289 (1) ◽  
pp. H295-H300 ◽  
Author(s):  
Masahiro Shibata ◽  
Shigeru Ichioka ◽  
Akira Kamiya

To examine the effects of vascular tone reduction on O2 consumption of the vascular wall, we determined the O2 consumption rates of arteriolar walls under normal conditions and during vasodilation induced by topical application of papaverine. A phosphorescence quenching technique was used to quantify intra- and perivascular Po2 in rat cremaster arterioles with different branching orders. Then, the measured radial Po2 gradients and a theoretical model were used to estimate the O2 consumption rates of the arteriolar walls. The vascular O2 consumption rates of functional arterioles were >100 times greater than those observed in in vitro experiments. The vascular O2 consumption rate was highest in first-order (1A) arterioles, which are located upstream, and sequentially decreased downstream in 2A and 3A arterioles under normal conditions. During papaverine-induced vasodilation, on the other hand, the O2 consumption rates of the vascular walls decreased to similar levels, suggesting that the high O2 consumption rates of 1A arterioles under normal conditions depend in part on the workload of the vascular smooth muscle. These results strongly support the hypothesis that arteriolar walls consume a significant amount of O2 compared with the surrounding tissue. Furthermore, the reduction of vascular tone of arteriolar walls may facilitate an efficient supply of O2 to the surrounding tissue.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mas Bayu Syamsunarno ◽  
Muh Kholik Maulana ◽  
Forcep Rio Indaryanto ◽  
Mustahal Mustahal

Abstract: This research aims to determine the optimum density in closed system transportation of milkfish juvenile. Milkfish juveniles used in the research had an average weight 1.48±0.12 g. The study consisted of several stages, namelydetermining the ability to fast fish, determining the level of oxygen consumption, determining the rate of excretion of total ammonia nitrogen and determining the optimum density in transportation for 48 hours.The treatments were performed differences in the density of 100, 150, 200, and 250 fish/L using polyethylene plastic size 35x50 cm and styrofoam size of 75 × 43 × 40 cm.The results showed the seed fish can survive and swim actively for 7 days without feeding with oxygen consumption rate as much as 2640 mgO2 and TAN excretion rate 0.1200 mg/L. The different treatment of density had an effect on the survival rate of milkfish juvenile. The optimal density for transportation of milkfish juvenile size 1.48 ± 0.12 g in a closed transportation system with a time of 48 hours is 150 juvenile/L with a 100% survival rate. At the density 250 juvenile/L, the can be done with a long time of 30 hours and resulted in a survival rate above 99%.  Keyword: Chanos chanos, Density, Transportation closed system, Survival rate, Water Quality Abstrak: Penelitian ini bertujuan untuk menentukan kepadatan optimal dan lama waktu dalam transportasi sistem tertutup benih ikan bandeng.Benih ikan bandeng yang digunakan memiliki bobot rata-rata 1,48±0,12g. Penelitian terdiri dari beberapa tahap, yaitu penentuan ketahanan ikan tanpa diberi makan, tingkat konsumsi oksigen, laju ekskresi total amoniak nitrogen dan kepadatan optimal benih ikan bandeng dalam transportasi selama 48 jam. Perlakuan yang dilakukan perbedaan kepadatan yaitu 100, 150, 200, dan 250 ekor/L dengan menggunakan plastik polyetylen (PE) ukuran 35x50 cm dan styrofoam ukuran 75×43×40 cm.Hasil penelitian menunjukkan benih ikan bandeng mampu bertahan hidup dan berenang aktif selama 7 hari pemuasaan ikan dengan tingkat konsumsi oksigen sebanyak 2640 mgO2 dan laju ekskresi TAN 0,1200 mg/L.Perlakuan perbedaan kepadataan berpengaruh terhadap kelangsungan hidup benih ikan bandeng.Kepadatan optimal untuk transportasi benih ikan bandeng ukuran 1,48±0,12 g/ekor pada sistem transportasi tertutup selama 48 jam adalah 150 ekor/L dengan tingkat kelangsungan hidup 100%. Pada kepadatan 250 ekor/L, transportasi dapat dilakukan dengan lama waktu 30 jam dan menghasilkan tingkat kelangsungan hidup di atas 99%. Kata Kunci: Ikan bandeng, Kepadatan, Kualitas Air, Transportasi sistem tertutup, Tingkat Kelangsungan Hidup


Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3150
Author(s):  
Jianye Xu ◽  
Siqi Zhou ◽  
Erdeng Du ◽  
Yongjun Sha ◽  
Lu Zheng ◽  
...  

The UV/chlorine process, as a new type of AOP (Advanced Oxidation Process), was utilized to treat amlodipine (AML)-containing water. The influencing factors, including chlorine dose, UV intensity, solution initial pH value, and ammonia concentration, were investigated. The degradation of AML in real water and the relative contributions of OH• and Cl• were also studied. Finally, high-resolution mass spectrometry (HRMS) and GC-MS were used to identify the possible degradation products. The results demonstrated that the AML degradation process was fitted with apparent first-order kinetics. AML degradation had a positive correlation with UV intensity and chlorine dose, and a negative correlation with ammonia concentration. In the presence of ammonia nitrogen and DOM, the removal of AML from real water was reduced. OH• made a dominant percentage contribution of 55.7% to the degradation of AML. Sixteen intermediates were detected and identified. A possible degradation mechanism was also proposed. Acute toxicity tests and risk prediction both illustrated that the complete removal of AML does not guarantee the reduction of acute toxicity, but a prolonged degradation promoted the detoxification of toxic intermediates. The UV/chlorine process can be regarded to be an effective method to remove AML and reduce ecological risk.


2013 ◽  
Vol 302 ◽  
pp. 119-123
Author(s):  
Hyun Jong Joo ◽  
Jung Soo Choi ◽  
Dong Wook Kwon ◽  
Sung Chang Hong

A new process for advanced wastewater treatment process has been devised with auxiliary treatment unit employing the ammonia oxidizing photo-catalytic thin film. In winter time, due to low water temperature, conventional nitrogen removal treatment experiences almost no nitrification by nitrifying bacteria. To solve the problem and to meet the governmental effluent guideline the treated water has been recycled through the auxiliary unit in which the auxiliary system was applied with the thin film coating photo-catalyst. This study also identifies the characteristics of the thin film coating-photo-catalyst through XRD, SEM and analyzes the ammonia nitrogen removal efficiency by using the thin film coating photo-catalyst in the reactor which resembles a sewage treatment process. The evaluation of the entire process of biological treatment in accord with the application of thin film coating photo-catalyst was performed through computer simulation. A relevant computer model for mass balance was made and utilized to select proper optimal operating condition such as recycle ratio. Result shows the proposed new process has potential applicability to renovate existing treatment plants.


2012 ◽  
Vol 610-613 ◽  
pp. 1760-1763
Author(s):  
Li Xu ◽  
Xue Wu ◽  
Ming Fen Niu ◽  
Si Li ◽  
Hong Jing Jiao ◽  
...  

The purpose of this paper is to obtain a start-up of short-cut nitrification systems to treat wastewater with high concentration of nitrogen and phosphorus under laboratory conditions. By starting the nitrification system at room temperature we can achieve the effective accumulation of nitrifying bacteria. Then by increasing experimental temperature and pH, and increasing the concentration of nitrogen and phosphorus in influent, to inhibit the growth of NOB in the systems and promote the accumulation of AOB. So we can make the effluent have a higher concentration of NO2--N. In the stable operation stage we can constantly improve ammonia concentration in the influent, to observe the stability of the each indicators of effluent. This experiment showed that the wastewater with high concentration of nitrogen and phosphorus can better promote the accumulation of AOB, to achieve the effect of short-range nitrification.


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