Hypolimnetic oxygenation: predicting performance using a discrete-bubble model

2001 ◽  
Vol 1 (4) ◽  
pp. 185-191 ◽  
Author(s):  
J.C. Little ◽  
D.F. McGinnis
Keyword(s):  
Negative Impact ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Pilot Scale ◽  
Bubble Plume ◽  
Predicting Performance ◽  
Aeration System ◽  
Hypolimnetic Oxygen ◽  
Hypolimnetic Oxygenation ◽  
Increase Oxygen Demand

Stratification of water-supply reservoirs frequently results in substantial hypolimnetic oxygen depletion with a resulting negative impact on raw water quality. Hypolimnetic oxygenators are used to add oxygen to the hypolimnion without significantly disrupting the thermal density structure. The three most common devices are the airlift aerator, the Speece Cone, and the bubble-plume diffuser. A discrete-bubble model based on fundamental principles has previously been shown to hold considerable promise for predicting the performance of airlift aerators and the Speece Cone. In this paper, we have further verified this model by comparing its predictions to a series of pilot-scale experimental measurements and have also demonstrated its ability, under somewhat idealized conditions, to predict the full-scale performance of a bubble-plume diffuser in a stratified reservoir. The potential for the diffused-bubble aeration system to increase oxygen demand, and the rate at which nitrogen builds up during operation and de-gasses following destratification, are also considered.

Study of the Oxygen Transfer Efficiencies in the Different Methods Used in the Technique of Hypolimnetic Aeration

2012 ◽  
Vol 452-453 ◽  
pp. 1014-1019 ◽  
Author(s):  
Gafsi Mostefa ◽  
Kettab Ahmed ◽  
Abdelkader Djehiche
Keyword(s):  
Oxygen Transfer ◽  
Thermal Stratification ◽  
Cold Water ◽  
Negative Impact ◽  
Drinking Water Treatment ◽  
Oxygen Depletion ◽  
Bubble Plume ◽  
Water Treatment Process ◽  
Aeration System ◽  
Lakes And Reservoirs

Thermal stratification of lakes and reservoirs can result in substantial hypolimnetic oxygen depletion, which may have a negative impact on the cold-water fisheries, the drinking water treatment process, and water quality downstream of hydropower reservoirs. Several techniques of aeration are presented in this study, to describe their effectiveness in control of physical and chemical parameters, that compromising the balance ecological and the thermal stratification in water supplies. As a result, we demonstrate that the most efficient hypolimnetic aeration system is the bubble plume diffuser; although an accidental destratification may occur. In hypolimnetic aeration systems, the aeration system by bubble plume appears to be the most economic and perhaps the simplest among the systems used in Stanley lake (Colorado, U.S.A), even as other researches select Speece Cone aeration system, or the full airlift systems, or the TVA line diffuser. The purpose of this study is to show the oxygen transfer efficiencies in the different methods used in the technique of hypolimnetic aeration, and their effect on the preservation of the thermal stratification. As well, this study concentrate on the economic and technical sides associated to these aeration systems.

Municipal waste sludge digestion in an autothermal aerobic sequencing batch reactor

2008 ◽  
Vol 58 (6) ◽  
pp. 1237-1243
Author(s):  
Gregor D. Zupanèiè ◽  
Viktor Grilc ◽  
Milenko Roš ◽  
Nataša Uranjek-Ževart
Keyword(s):  
Batch Reactor ◽  
Oxygen Demand ◽  
Batch Process ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Pure Oxygen ◽  
Sludge Digestion ◽  
Scale Size ◽  
Aeration System ◽  
Maximum Temperatures

An autothermal aerobic sequencing batch process for sludge digestion and “class A” biosolids production was developed. The process was tested in laboratory and pilot scale size up to 150 PE, which can be considered a full scale size in some cases. In this process the maximum temperatures of 61.2°C and 60.2°C were achieved in laboratory scale in pilot scale equipment, respectively. The degradation efficiency of total chemical oxygen demand of sludge was between 50 and 70%. Similar results were achieved using pure oxygen in laboratory scale and oxygen/air mixture 1:1 by volume. The reactor scale greatly affects the achievement of thermophilic temperature. In smaller sizes the convective heat losses are the prevailing heat sink and the process is unable to produce enough heat to reach thermophilic temperature. Larger systems produce excess heat and can be installed with less intense aeration systems. The limit of air aeration system is at the size of about 500 PE.

APLIKASI PROSES DIGESTASI ANAEROBIK LUMPUR BIOLOGI INSTALASI PENGOLAHAN AIR LIMBAH INDUSTRI KERTAS

2014 ◽  
Vol 4 (02) ◽  
Author(s):  
Rina S. Soetopo ◽  
Sri Purwati ◽  
Henggar Hardiani ◽  
Mukharomah Nur Aini ◽  
Krisna Adhitya Wardhana
Keyword(s):  
Oxygen Demand ◽  
Total Solid ◽  
Pilot Scale ◽  
Organic Content ◽  
Solid Content ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Total Solid Content ◽  
Average Value

A continuous pilot scale study has been conducted to investigate the effectiveness of anaerobic digestion of biological sludge. The sludge has a total solid content of 0.53% - 1.1%, pH of 7.20 to 7.32. Its organic content is about 97 %, The research were conducted in two stages, which are acidification (performed in 3 m3 the Continously Stirred Tank Reactor/CSTR at pH of 5.5 to 6.0) and methanation (performed in 5 m3 the Up Flow Anaerobic Sludge Blanket/UASB reactor at pH 6.5 to 7.0). The retention time (RT) was gradually shortened from 6 days to 1 day for acidification and from 8 days to 2 days for methanation. The results showed that operating the CSTR at the RT of 1 day and the organic loading of 8.23 g Volatile Solid (VS)/m3.day could produce Volatile Fatty Acid (VFA) at an average value of 17.3 g/kg VS.day. Operating the UASB reactor at the RT of 2 days and the organic loading (Chemical Oxygen Demand/COD) of 2.4 kg COD/m3.day could produce biogas at an average value of 66.3 L/day, with an average methane content of 69.9%, methane rate of 0.17 L CH4/g COD reduction or 19.06 L CH4/kg VS. Furthermore, methanation could reduce COD at an average value of 51.2 %, resulting in the effluent average value of COD filtrate and COD total of 210.1 mg/L and 375.2 mg /L, respectively.Keywords: acidification, methanation, CSTR, UASB, biogas ABSTRAKPercobaan digestasi anaerobik lumpur IPAL biologi industri kertas secara kontinyu skala pilot telah dilakukan di industri kertas dengan tujuan mengkaji efektivitas proses digestasi anaerobik dalam mengolah lumpur tersebut. Lumpur yang digunakan memiliki total solids sekitar 0,53% – 1,1%, pH netral (7,20 – 7,32) dengan komponen utama senyawa organik sekitar 97%. Percobaan dilakukan dalam dua tahap yaitu asidifikasi dalam reaktor CSTR berkapasitas 3 m3 pada pH 5,5 – 6,0 dan metanasi dalam reaktor UASB berkapasitas 5 m3 pada pH 6,5 – 7,0. Percobaan dilakukan dengan waktu retensi yang dipersingkat secara bertahap dari 6 hari ke 1 hari untuk proses asidifikasi dan dari 8 hari ke 2 hari untuk proses metanasi. Hasil percobaan menunjukkan bahwa pengoperasian reaktor CSTR dengan waktu retensi 1 hari dan beban organik 8,3 g VS/m3.hari dapat menghasilkan VFA rata-rata 17,3 g/kg VS.hari dengan kisaran 8,36 – 30,59 g/kg VS.hari, sedangkan pengoperasian reaktor UASB pada waktu retensi 2 hari dan beban organik 2,4 kg COD/m3.hari dapat menghasilkan biogas rata-rata 66,3 L/hari dengan kadar metana rata-rata 69,9% atau 0,17 L CH4/g COD reduksi atau 19,06 L CH4/kg VS. Selain itu proses metanasi dapat menurunkan COD terlarut rata-rata 51,2%, dengan konsentrasi efluen COD terlarut  rata-rata 210,1 mg/L dan COD total rata-rata 375,2 mg/L.Kata kunci: asidifikasi, metanasi, CSTR, UASB, biogas

ECOLOGICAL AND TOXICOLOGICAL ASSESSMENT OF HAZARD, POSED BY WATER CONTAMINATION OF WATER BODIES WITH POLYVINYL NITRATE

2018 ◽  
pp. 12-19 ◽  
Author(s):  
A. A. Maslennikov ◽  
S. A. Demidova ◽  
A. V. Ryabova
Keyword(s):  
Biochemical Oxygen Demand ◽  
Water Contamination ◽  
Chronic Toxicity ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Water Bodies ◽  
Organoleptic Properties ◽  
Toxicological Assessment ◽  
Threshold Levels ◽  
Polyvinyl Nitrate

Water containing polyvinyl nitrate was experimentally assessed on the basis of organoleptic, general sanitary and toxicological indicators of harmfulness. It was established that that the compound did not change water organoleptic properties but produced a negative impact on viability of saprophytic microflora , nitrification processes and biochemical oxygen demand. Besides, in tests on animals. the substance caused acute, sub-acute and chronic toxicity. Based on those signs of harmfulness, threshold levels of exposure were established. Data obtained were taken into account for substantiation of MAC (Maximum allowable concentration) of polyvinyl nitrate in water bodies.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Yanjun Mao ◽  
Xie Quan ◽  
Huimin Zhao ◽  
Yaobin Zhang ◽  
Shuo Chen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Full Scale ◽  
Nitrification And Denitrification ◽  
Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

Experimental manipulations of the biomass of introduced carp (Cyprinus carpio) in billabongs. II. Impacts on benthic properties and processes1

1997 ◽  
Vol 48 (5) ◽  
pp. 445 ◽  
Author(s):  
A. I. Robertson ◽  
M. R. Healey ◽  
A. J. King
Keyword(s):  
Algal Biomass ◽  
Solid Phase ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Sediment Surface ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Biofilm Development ◽  
The Impact

Two billabongs on the floodplain of the Murrumbidgee River, Australia, were partitioned in half with impermeable plastic barriers and the biomass of carp was manipulated to establish high- and low-carp biomass treatments in each billabong. Measurements of benthic variables (rates of particle settlement, biofilm development, sediment respiration, macrophyte detritus decomposition, sediment solid-phase nutrient concentrations and benthic algal biomass) were performed over four months from summer to winter 1995. Rates of particle settlement were greater in the high-carp treatment of each billabong throughout the experiment. High carp biomass had a negative impact on the autotrophic component of the biofilm developing on wood blocks placed at different heights above the sediment surface but the mechanism responsible differed between billabongs. Sediment oxygen demand became greater in the presence of a higher biomass of carp during the experiment but time courses differed between billabongs. Manipulations of carp biomass did not influence algal biomass on the sediment surface, the rate of decomposition of macrophyte detritus or sediment solid-phase nutrients or nutrient ratios. The impact of carp on benthic and surficial processes was significant but the mechanisms of change differed between billabongs.

scholarly journals Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions

2015 ◽  
Vol 71 (7) ◽  
pp. 1088-1096 ◽  
Author(s):  
B. Kim ◽  
M. Gautier ◽  
G. Olvera Palma ◽  
P. Molle ◽  
P. Michel ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Phosphorus Removal ◽  
Water Saturation ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Saturation Level ◽  
Vertical Flow ◽  
Trickling Filter ◽  
Operational Conditions ◽  
Vertical Flow Constructed Wetland

The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.

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