Program on Treatment of the Landfill Leachate by Onland Planting Reed (Phragmites)

2011 ◽  
Vol 71-78 ◽  
pp. 2852-2855
Author(s):  
Kun Shi ◽  
Ming Zou
Keyword(s):  
Removal Efficiency ◽  
Constructed Wetland ◽  
Landfill Leachate ◽  
Retention Time ◽  
Suspended Solids ◽  
Preferential Flow ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Surface Loading ◽  
Waste Landfill

The microcosm tests were done to estimated the HRT (Hydraulic Retention Time) and removal efficiency of reflowing treatment of the landfill leachate collected from Dalian Maoyingzi Municipal Solid Waste Landfill, which contained high levels of COD (Chemical Oxygen Demand, 38400 mg/L) and SS (Suspended Solids, 650 mg/L) by the reed constructed wetland located in the south area of Dalian Jiaotong University. The results showed that: (1) The HRT in nature soil cuboids were significant shorter than those in sieved soil cuboids (P<0.01); (2) The removal efficiency among the output water with the trend as follows: Preferential flow (53.9%)<Percolating water (59.2%)<Reflowing water (63.3%); (3) The COD and SS were decreased from 38400 and 650 mg/L to 14080 and 213 mg/L by the way of reflowing with the HSL (Hydraulic Surface Loading) of 0.16 m3/(m2·d) by reflowing (Removal efficiency: COD: 63.3%; SS: 67.3%).

scholarly journals Effect of hydraulic retention time on chemical oxygen demand and total nitrogen removal in intermittently aerated constructed wetlands

2020 ◽  
Vol 15 (3) ◽  
pp. 1 ◽  
Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Intermittent Aeration

   This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.

scholarly journals QUALITATIVE RESEARCH AND EVALUATION OF LANDFILL LEACHATE / KOKYBINIAI SĄVARTYNO FILTRATO TYRIMAI IR VERTINIMAS

2013 ◽  
Vol 5 (4) ◽  
pp. 356-362 ◽  
Author(s):  
Irina Kačinskaja ◽  
Kristina Bazienė ◽  
Saulius Vasarevičius
Keyword(s):  
Experimental Data ◽  
Landfill Leachate ◽  
Suspended Solids ◽  
Environmental Problem ◽  
Oxygen Demand ◽  
Optimal Operation ◽  
Municipal Waste ◽  
Vital Activity ◽  
Waste Landfill ◽  
Calcium And Magnesium

Currently, depositing municipal waste in landfills is the dominating method in Lithuania. A large amount of landfill leachate is the main environmental problem. Municipal waste landfill leachate is characterized by high biochemical oxygen demand (BOD) containing a number of heavy metals and concentration of organic compounds. The colmatation of landfill leachate collection systems is another burning problem that occurs due to certain characteristics of leachate such as suspended solids, an increase in calcium and magnesium concentrations and vital activity of microorganisms. Therefore, it is necessary to examine conditions affecting these parameters. The paper presents and analyses the characteristics of experimental data, assesses the factors having the greatest influence on recent development and introduces the measures that should be taken into account so that to the ensure optimal operation of the systems for collecting municipal waste landfill leachate. Article in Lithuanian. Santrauka Pagrindinis atliekų tvarkymo būdas Lietuvoje yra jų deponavimas sąvartynuose. Viena iš svarbiausių aplinkosauginių problemų – dideli susidarantys sąvartyno filtrato kiekiai. Komunalinių atliekų sąvartynų filtratui būdinga didelis biocheminio deguonies suvartojimas (BDS), filtrate taip pat nemažà sunkiųjų metalų bei organinių junginių koncentracija. Svarbu išskirti ir tokią problemą kaip sąvartyno filtrato surinkimo sistemų kolmatacija, pasireiškianti dėl tam tikrų filtrato savybių: skendinčiųjų medžiagų, kalcio ir magnio koncentracijų padidėjimo ir mikroorganizmų gyvybinės veiklos. Būtina įvertinti sąlygas, turinčias įtakos šių parametrų kitimui. Pateikti minėtų savybių eksperimentinių tyrimų duomenys ir analizė. Įvertinta, kokie veiksniai turi didžiausią įtaką filtrato parametrų kitimui, pavyzdžiui, tai, jog bendrasis kietumas (kalcis ir magnis) lemia pH didėjimą, t. y. terpės šarmėjimą. Be to, išanalizuota, kokių priemonių reikėtų imtis optimaliam komunalinių atliekų sąvartyno filtrato surinkimo sistemų veikimui užtikrinti.

scholarly journals The potential of ultrasonic membrane anaerobic systems in treating slaughterhouse wastewater

2015 ◽  
Vol 5 (3) ◽  
pp. 293-300 ◽  
Author(s):  
N. H. Abdurahman ◽  
Y. M. Rosli ◽  
N. H. Azhari ◽  
Hayder A. Bari
Keyword(s):  
Steady State ◽  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Yield Coefficient ◽  
Slaughterhouse Wastewater ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids (TSS) and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached 94.8%.

scholarly journals Dynamics of Archaeal and Bacterial Communities in Response to Variations of Hydraulic Retention Time in an Integrated Anaerobic Fluidized-Bed Membrane Bioreactor Treating Benzothiazole Wastewater

Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yue Li ◽  
Qi Hu ◽  
Da-Wen Gao
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Retention Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
High Strength ◽  
Service Period ◽  
Miseq Platform

An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) was investigated to treat synthetic high-strength benzothiazole wastewater (50 mg/L) at a hydraulic retention time (HRT) of 24, 18, and 12 h. The chemical oxygen demand (COD) removal efficiency (from 93.6% to 90.9%), the methane percentage (from 70.9% to 69.27%), and the methane yield (from 0.309 m3 CH4/kg·CODremoved to 0.316 m3 CH4/kg·CODremoved) were not affected by decreasing HRTs. However, it had an adverse effect on membrane fouling (decreasing service period from 5.3 d to 3.2 d) and benzothiazole removal efficiency (reducing it from 97.5% to 82.3%). Three sludge samples that were collected on day 185, day 240, and day 297 were analyzed using an Illumina® MiSeq platform. It is striking that the dominant genus of archaea was always Methanosaeta despite of HRTs. The proportions of Methanosaeta were 80.6% (HRT 24), 91.9% (HRT 18), and 91.2% (HRT 12). The dominant bacterial genera were Clostridium in proportions of 23.9% (HRT 24), 16.4% (HRT 18), and 15.3% (HRT 12), respectively.

Treatment of Domestic Strength Wastewater with Anaerobic Hybrid Reactors

1987 ◽  
Vol 22 (3) ◽  
pp. 474-490 ◽  
Author(s):  
R.L. Droste ◽  
S.R. Guiot ◽  
S.S. Gorur ◽  
K.J. Kennedy
Keyword(s):  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Synthetic Wastewater ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Removal Efficiencies ◽  
Hybrid Reactors

Abstract Anaerobic treatment of dilute synthetic wastewater (300-1,000 mg chemical oxygen demand/L using laboratory upflow sludge blanket filter reactors with and without effluent recycle is described. Treatment of dilute synthetic wastewater at hydraulic retention times less than 1 and 2 h in reactors without and with recycle, respectively, resulted in biomass washout as the solids retention time decreased to less than 12 d. Reseeding would be required to operate at these critical hydraulic retention times for extended periods. Treatment of dilute synthetic wastewater at hydraulic retention times between 3-12 h resulted in soluble COD removal efficiencies between 84-95% treating 300 mg COD/L. At a 3 h hydraulic retention time, solids retention time of 80 d and stable reactor biomass concentrations of 25 g volatile suspended solids/L were maintained.

Removal efficiency of the constructed wetland wastewater treatment system at Bainikeng, Shenzhen

1995 ◽  
Vol 32 (3) ◽  
pp. 31-40 ◽  
Author(s):  
Yang Yang ◽  
Zhencheng Xu ◽  
Kangping Hu ◽  
Junsan Wang ◽  
Guizhi Wang
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Design Flow ◽  
Treatment System ◽  
Wastewater Treatment System ◽  
Tennessee Valley ◽  
Wetland System

In this paper, three years study on a constructed wetland wastewater treatment system at Bainikeng, Shenzhen, is reviewed and summarized. The wetland system under study occupies an area of 8400m2, with a design flow of 3100 m3 per day. The study was conducted to understand removal efficiencies of constructed wetland systems for municipal wastewaters from small or medium scale towns in the sub-tropics. Such parameters as biological oxygen demand, chemical oxygen demand, suspended solids, total nitrogen, and total phosphorus in the influent and effluent of the wetland system are examined, and their removal rates are determined. It is shown that the system is very effective in removing organic pollutants and suspended solids and its removal efficiency is much similar to those of the constructed wetlands at Tennessee Valley Authority (TVA) (Choate et al., 1990) while better than those of conventional secondary biochemical treatments.

Biodegradation of Wool Scouring Effluent on a Laboratory Scale

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2101-2104 ◽  
Author(s):  
R. A. Oellermann ◽  
T. Ronen ◽  
V. Meyer
Keyword(s):  
Chemical Oxygen Demand ◽  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Rotating Biological Contactor ◽  
Anaerobic Reactor ◽  
Biomass Retention ◽  
Aerobic Reactor ◽  
Mixed Systems

A continuously fed, sequential anaerobic-aerobic-aerobic reactor system was used to treat wool scouring effluent. The chemical oxygen demand (COD) in the anaerobic reactor was reduced from 30500 mg/ℓ to 3000-5000 mg/ℓ. In the first aerobic reactor this was further reduced to 1200-1800 mg COD/l. The final discharge from the second aerobic reactor had a COD of 500-1000 mg/ℓ at a hydraulic retention time of 2-3 d. Nitrification was erratic but sufficient to reduce the ammonia-N to levels of 20 mg/ℓ and less. Mixed liquor suspended solids and volatile suspended solids could be maintained at sufficiently high levels in completely mixed systems and efficient biomass retention in the aerobic rotating biological contactor resulted in an overall removal of 98.4% COD.

Domestic wastewater treatment by a constructed wetland system planted with rice

2011 ◽  
Vol 64 (12) ◽  
pp. 2376-2380 ◽  
Author(s):  
Suwasa Kantawanichkul ◽  
Wanida Duangjaisak
Keyword(s):  
Wastewater Treatment ◽  
Chemical Oxygen Demand ◽  
Constructed Wetland ◽  
Retention Time ◽  
Paddy Field ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Biological Oxygen Demand ◽  
Removal Efficiencies

The experiments were conducted in four concrete laboratory scale free water surface constructed wetland units 1 m wide, 1.5 m long and 0.8 m deep. Paddy field soil was added to a depth of 0.4 m and rice seedlings (Oryza sativa L.) were transplanted into the units at a density of 25 plants/m2. Domestic wastewater collected from Chiang Mai University was applied into each unit via two different modes to evaluate suitable conditions for wastewater treatment and rice yield. In the first experiment, the wastewater was fed intermittently (7 h/day) with a hydraulic loading rate of 2, 4, 6 and 8 cm/day. The maximum removal efficiencies for chemical oxygen demand, biological oxygen demand, total kjedahl nitrogen and suspended solids were only 49.1, 58.7, 64.0 and 59.4%, respectively, due to the short hydraulic retention time for the biodegradation of organic substances. In the second experiment, the wastewater in each unit was inundated to a depth of 15 cm for 10, 15, 20 and 25 days in each unit and then drained and re-flooded. Removal efficiencies of chemical oxygen demand, biological oxygen demand, total kjedahl nitrogen and suspended solids were greater than in the first experiment especially at the 25 day retention time and except for suspended solids met the Thai national effluent standard. The study revealed that apart from wastewater treatment, wastewater can replace natural water to grow rice in the dry season or throughout the year. Moreover, nutrients in wastewater can be a substitute for chemical fertilizers. Rice grain production was 4,700 kg/ha and only 6% less than the production from the conventional paddy field.

The vortex concentrator for suspended solids treatment

2003 ◽  
Vol 47 (7-8) ◽  
pp. 335-341 ◽  
Author(s):  
J. Lee ◽  
K. Bang ◽  
J. Choi ◽  
L.H. Ketchum ◽  
Y. Cho
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Combined Sewer Overflows ◽  
Surface Loading ◽  
Solids Concentration ◽  
Coagulant Dosage ◽  
Combined Sewer ◽  
Retention Basin

The use of vortex concentrators is becoming increasingly popular for suspended solids reduction in combined sewer overflows and stormwater. This study is a laboratory investigation of the use of vortex concentrators to reduce the solids concentration of synthesized stormwater. The synthesized stormwater was made with water and addition of particles; sand, granular activated carbon, and sewer sediments. The vortex concentrator was made of acryl resin 300 mm in diameter. To determine the efficiency for various influent suspended solids (SS) concentrations, tests were performed with different SS concentrations. The samples were taken simultaneously at the influent storage tank and effluent tank, and measured SS concentrations. The range of surface loading rates were 120 to 850 m3/m2/day, and influent SS concentrations were varied from 300 to 5,000 mg/L. To determine the optimum coagulant dosage, jar tests were conducted with coagulants such as PAM and PAC. It was found that optimum coagulant and its dosage were PAM and 2 mg/L. The overall SS removal efficiency of the vortex concentrator for typical stormwater was estimated at about 65%. With an increase of SS concentration, the removal efficiency was increased. Since the SS concentration of stormwater was higher than 1,000 mg/L, the removal efficiency of the vortex concentrator for stormwater could be estimated to be 65-70%. The SS removal efficiency was increased with an increase of retention time, and the optimum retention time was 0.15-1.0 minutes. With an increase of the foul to overflow QF/Qo, a key parameter for vortex concentrator operation, the removal efficiency was increased. An alternative solution to improve treatment efficiency might be to set a follow-up retention basin. Based on a series of settling tests on the treated overflow water from the vortex concentrator, 5 to 10 minutes hydraulic retention time in a follow-up retention basin would substantially improve the results.

scholarly journals Efficiency of the work of almond shells as biological carriers in activated sludge aeration tanks: كفاءة عمل قشور اللوز كحوامل بيولوجية في أحواض التهوية بالحمأة المنشطة

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Raghad Salim Al-Shalabi, Naeima Ajib, Mahmoud Fattamah
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Aeration Tank ◽  
Sludge Treatment ◽  
Mixed Liquor ◽  
Conventional Activated Sludge ◽  
Fixed Film

Based on the interest in environmentally friendly materials for wastewater treatment, this research is aimed at evaluating the efficiency of almond shells work as biological carriers in activated sludge aeration tanks, known as the integrated fixed-film activated sludge treatment, a hybrid tank with attached growth and suspended growth is obtained. Almond shells were placed at 7% of the size of the aeration tank throughout the experiment period for about 4 months with a number of indicators such as hydraulic retention time and mixed liquor suspended solids. Two sets of experiments were performed, the first group with a constant hydraulic retention time ( HRT= 4 hours), and mixed liquor suspended solids was changed (500-1000-2000-3000 mg/ L), with the best removal efficiency at MLSS = 2000 mg/ l, by 91.3% and 92.1% for COD and SS respectively. The optimal MLSS concentration was adopted for the second group of experiments where HRT was increased to 5 and 6 hours. As a result, the best chain was found to be MLSS = 2000 mg/ l and HRT = 5 hours, with a removal efficiency of 93.4% and 93.9% for COD and SS respectively. As a result, the rate of return activated sludge was reduced from 100% to 60% and the rate of inflow into the aeration tank was increased due to the reduction HRT from 6 hours to 5 hours compared to conventional activated sludge treatment.

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