Performance of an in-situ rotating biological contactor in a recirculating aquaculture system

2011 ◽  
Vol 64 (11) ◽  
pp. 2217-2222
Author(s):  
P. Marin ◽  
A. Donoso-Bravo ◽  
J. L. Campos ◽  
G. Ruiz-Filippi ◽  
R. Chamy
Keyword(s):  
Rainbow Trout ◽  
Removal Rate ◽  
Synthetic Medium ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Negative Effects ◽  
Rotating Biological Contactor ◽  
Operational Conditions ◽  
Recirculating Aquaculture

The start-up and activation of a nitrifying rotating biological contactor (RBC) and its performance inside a culture tank of rainbow trout were studied. First, in a lab-scale operation, the system was fed with a synthetic medium containing a high ammonia concentration (567 mg NH4+-N L−1) and operated at a high hydraulic retention time (HRT) (6.5 days) to minimize the wash-out of the biomass and promote the biofilm formation. Then, both inlet ammonia concentration and HRT were decreased in order to obtain operational conditions similar to those of the culture tank. During this period, the RBC was able to treat an ammonia loading rate (ALR) of 0.64 g N-NH4+ L−1 d−1 with a removal efficiency within 70–100%. Pilot-scale experiments were carried out in culture tanks of rainbow trout. The operation of a recirculating system with the RBC unit was compared with a recirculating system without biological treatment and with a flow-through system. The use of this in-situ nitrifying unit allowed working at a recirculation ratio of 90% without negative effects on either growth or the condition factor of fishes. Up to 70% of ammonia generated was removed and a removal rate of 1.41 g NH4+-N m−2 d−1 was reached.

scholarly journals Characteristics of Ammonia Removal and Nitrifying Microbial Communities in a Hybrid Biofloc-RAS for Intensive Litopenaeus vannamei Culture: A Pilot-Scale Study

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3000
Author(s):  
Wujie Xu ◽  
Yu Xu ◽  
Haochang Su ◽  
Xiaojuan Hu ◽  
Keng Yang ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Litopenaeus Vannamei ◽  
Removal Rate ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Ammonia Removal ◽  
Shrimp Culture ◽  
Recirculating Aquaculture ◽  
Total Ammonia ◽  
High Feed

Ammonia is the main pollution factor of the aquatic environment in marine shrimp culture systems. In order to demonstrate the feasibility of the combination of biofloc technology and nitrifying biofilter for the ammonia removal, a 70-day production trial was conducted in a simplified pilot-scale hybrid biofloc-based recirculating aquaculture system (biofloc-RAS) with the intensive culture of Litopenaeus vannamei. Nitrogen dynamics and nitrifying microbial communities were investigated in three replicated systems simultaneously under the conditions of high feed loading and zero water exchange. Along with biofloc development in the culture tank and biofilm formation in the nitrifying biofilter during the trial, nitrification could be fastly and effectively established in the system, which was indicated by the dynamics of total ammonia nitrogen (TAN), NO2–-N, NO3–-N, and total nitrogen (TN) concentrations. Meanwhile, similar nitrifying microorganisms could be found between biofloc and biofilm, despite some differences in abundance, diversity, and composition of ammonia-oxidizing archaea and bacteria and nitrite-oxidizing bacteria. High TAN removal rate could be achieved and was significantly and positively correlated with abundances of these nitrifying microbial communities in both biofloc and biofilm, further indicating that both biofloc and biofilm could contribute highly to nitrification performance of the biofloc-RAS. The results of this study indicate a potential application of the biofloc-RAS in coastal intensive aquaculture.

scholarly journals Determination of optimum operational conditions for the removal of 2-MIB from drinking water by peroxone process: a pilot-scale study

2020 ◽  
Vol 20 (6) ◽  
pp. 2339-2347
Author(s):  
M. Fakioglu ◽  
H. Gulhan ◽  
H. Ozgun ◽  
M. E. Ersahin ◽  
I. Ozturk
Keyword(s):  
Drinking Water ◽  
Contact Time ◽  
Advanced Oxidation Process ◽  
Removal Rate ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Operational Conditions ◽  
Taste And Odor ◽  
Water Supply And Treatment

Abstract Taste and odor in drinking water are one of the main problems of the water supply and treatment sector. Peroxone is an effective advanced oxidation process, which combines ozone with hydrogen peroxide to create hydroxyl radicals that decompose organic compounds. 2-Methylisoborneol (2-MIB) is one of the significant taste and odor causing compounds, which can be removed with the peroxone process. In this study, removal of a 2-MIB compound by peroxone process was investigated in a pilot-scale treatment plant and optimum operational conditions were determined. For safety reasons, it is important that residual O3 and H2O2 concentrations in the water leaving the reactor should not exceed 0.1 and 0.5 mg/L, respectively. Results indicate that while dissolved ozone concentration was below the indicated limit for all experiments, concentrations over 0.5 mg/L residual H2O2 were observed during the experiments with an H2O2:O3 ratio of 0.5. This limit exceedance affected the decision on the ideal peroxone ratio along with the 2-MIB removal results. Therefore; optimum H2O2:O3 ratio was determined as 0.3. 2-MIB removal efficiency of 81% was achieved at the optimum H2O2:O3 ratio with a contact time of 15 min. According to the results, 2-MIB removal rate had a linear correlation with the contact time.

Granulation of Anammox microorganisms in up-flow reactors

2004 ◽  
Vol 49 (5-6) ◽  
pp. 155-164 ◽  
Author(s):  
U. Imajo ◽  
T. Tokutomi ◽  
K. Furukawa
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Synthetic Medium ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Uasb Reactor ◽  
Flow Reactors ◽  
Reject Water ◽  
Pilot Scale Reactor ◽  
Scale Reactor

Experimental studies were performed to evaluate the feasibility of granulation of Anammox microorganisms for biomass retention in up-flow reactors. Two experimental studies, one using a 6.4-L lab-scale reactor with synthetic medium and the other using a 200-L pilot-scale reactor with half-nitrified reject water from a sludge digester were conducted. To enhance the granulation process, seed granules from a UASB reactor were added to both experimental reactors. Granulation of Anammox microorganisms was observed using both the synthetic medium and the reject water. The core of a large proportion of Anammox granules retained part of the original seed biomass. The Anammox granules had a slightly lower density than the seed granules from the UASB process, but the size and other physical properties were comparable. The successful granulation of the Anammox microorganisms led to a stable nitrogen removal performance. The maximum nitrogen removal rate of the lab-scale reactor was observed to be 2.9 kg/(m3·d) after 173 days of operation and that of the pilot-scale reactor was 6.4 kg/(m3·d) after 12 months of operation.

Nitrite accumulation in the treatment of wastewaters with high ammonia concentration

2003 ◽  
Vol 48 (3) ◽  
pp. 135-141 ◽  
Author(s):  
W. Yang ◽  
J. Vollertsen ◽  
T. Hvitved-Jacobsen
Keyword(s):  
Nitrous Acid ◽  
Ammonia Oxidation ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Nitrite Accumulation ◽  
Operational Parameters ◽  
Treatment Unit ◽  
Operational Conditions ◽  
Reject Water ◽  
Oxidation Rates

Different operational parameters of the nitritation process were investigated in both jar tests and pilot scale Sequencing Batch Reactors (SBRs). In the laboratory study, 100-1,200 mg N l-1 of ammonia was used. The pH and temperature were varied. Batch experiments were done on municipal sludge, pectin industrial sludge and sludge from a reject water treatment unit. Ammonia oxidation was observed with relative nitrite accumulations from 2% to 100% and ammonia oxidation rates from 0.01 to 0.58 g N g VSS-1 d-1. The nitritation process and relative nitrite accumulation were highly affected by pH, temperature and the sludge type. pH 8.0-8.5 and temperature 30°C were found favourable for the nitritation. Pilot SBR systems for treating reject water achieved 100% of nitrite accumulation under the operational conditions of pH 7.5-8.0, temperature 30°C and dissolved oxygen (DO) 1.0 mg l-1. Six months of operation revealed that pH regulations were essential to avoid the inhibitions by either free ammonia or nitrous acid. At an unionized ammonia concentration of approximately 20 mg NH3-N l-1, half of the normal nitritation ability still remained. Total inhibition occurred when the concentration of nitrous acid reached 3.0 mg HNO2-N l-1. However, both types of inhibitions were reversible in the SBR with a proper operation control. Stable and controllable nitritation could be achieved in pilot scale.

Nitrification studies on fertilizer wastewaters in activated sludge and biofilm reactors

1995 ◽  
Vol 32 (12) ◽  
pp. 141-148 ◽  
Author(s):  
Ferhan Çeçen ◽  
Elvan Orak ◽  
Pinar Gökçin
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Continuous Flow ◽  
Removal Rate ◽  
Ammonia Concentration ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Nitrite Accumulation ◽  
Operational Conditions ◽  
Oxygen Concentrations

Nitrification characteristics of a high-strength fertilizer wastewater were studied in a batch activated sludge and a continuous-flow biofilm reactor. In a batch activated sludge system one of the most decisive factors was the pH control. The results in terms of ammonium decrease and nitrite build-up were fitted to kinetic models and it was shown that in the absence of inhibitory factors like high free ammonia or nitrous acid build-up the behaviour was similar to that in the case of low-strength wastes. Continuous-flow studies in the biofilm reactor at different loading rates and dissolved oxygen concentrations indicated that such a biofilm reactor could be employed in the treatment of highly nitrogenous fertilizer wastes. Depending on operating conditions such as dissolved oxygen concentration and loading rate an effluent ammonia concentration as low as 4 mg NH4−N/L could be achieved. In the dissolved oxygen ranges of 3.2 mg/L–3.5 mg/L the system reached the maximum removal rate of 0.17 kg NH4−N/m3.d. When the dissolved oxygen was increased to 4.9 mg/L, removal rates as high as 0.41 kg NH4−N/m3.d could be obtained. Also in continuous-flow operation nitrite accumulation reached in some cases a considerable degree depending on the bulk nitrogen and dissolved oxygen concentrations. The nitrite accumulation in the effluent stream varied from 4–180 mg NO2−N/L depending on operational conditions.

Removal of cyanide from acrylonitrile wastewater using gas membrane

2011 ◽  
Vol 64 (11) ◽  
pp. 2274-2281 ◽  
Author(s):  
Jinling Wu ◽  
Jianlong Wang ◽  
Haiyang Liu ◽  
Shijun He ◽  
Xia Huang
Keyword(s):  
Membrane Fouling ◽  
Removal Rate ◽  
Treatment Strategies ◽  
Pilot Scale ◽  
Inorganic Salts ◽  
Operational Parameters ◽  
High Concentration ◽  
Operational Conditions ◽  
Industrial Wastewaters ◽  
Pre Treatment

Acrylonitrile wastewater is one of the most refractory industrial wastewaters as it contains cyanide at a high concentration. This study introduced a safe, effective and economic strategy, that is, use of the gas membrane to acrylonitrile wastewater treatment. Due to the complicated constituents of acrylonitrile wastewater, cyanide removal rate by gas membrane is very low. In order to enhance HCN removal, the operational conditions were optimized; pre-treatment strategies for fouling mitigation were also proposed and tested for acrylonitrile wastewater. The optimal operational parameters were achieved at an acidified pH of 5.0, wastewater velocity of 0.14 m s−1, NaOH concentration of 10% and a temperature of 40 °C. The major factor affecting HCN removal was the pH of the acidified wastewater. The reason for the low removal rate was further explored and found to be the decrease of HCN transfer coefficient, which was caused by membrane fouling. Furthermore, the predominant foulants have been identified as colloidal organic materials and inorganic salts. Alkalization, which is effective in reducing these materials, has been proven to be most effective in mitigating membrane fouling and improving HCN removal, which was also confirmed by a pilot-scale study. The overall removal rate was therefore significantly enhanced to 87.1%.

Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Mass Balance ◽  
Particulate Organic Matter ◽  
Removal Rate ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Synthetic Wastewater ◽  
Aerobic Conditions ◽  
Biofilm Reactors ◽  
Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

On-site and in situ bioremediation of wood-preservative contaminated groundwater

2000 ◽  
Vol 42 (5-6) ◽  
pp. 371-376 ◽  
Author(s):  
J.A. Puhakka ◽  
K.T. Järvinen ◽  
J.H. Langwaldt ◽  
E.S. Melin ◽  
M.K. Männistö ◽  
...  
Keyword(s):  
Iron Oxidation ◽  
Wood Preservative ◽  
Pilot Scale ◽  
High Rate ◽  
Contaminated Groundwater ◽  
Groundwater Temperature ◽  
In Situ Bioremediation ◽  
Contaminated Aquifer ◽  
Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

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