Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons

2015 ◽  
Vol 71 (6) ◽  
pp. 938-946 ◽  
Author(s):  
R. H. K. Al-Isawi ◽  
A. Sani ◽  
S. A. A. A. N. Almuktar ◽  
M. Scholz
Keyword(s):  
Positive Impact ◽  
Oxygen Demand ◽  
Aggregate Size ◽  
Ammonia Nitrogen ◽  
Flow Mode ◽  
Vertical Flow ◽  
Treatment Standards ◽  
Diesel Spill ◽  
The Impact ◽  
Outflow Concentration

The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO3-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO4-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO4-P and SS. The wetland with the largest aggregate size had the lowest mean NO3-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO3-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal.

scholarly journals Impact of Partially Treated Wastewater on Downstream Water Quality of Notwane River in Botswana

2018 ◽  
pp. 1-9
Author(s):  
Gilbert K. Gaboutloeloe ◽  
Gugu Molokwe ◽  
Benedict Kayombo
Keyword(s):  
Water Quality ◽  
Pearson Correlation ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Treated Wastewater ◽  
Nitrate N ◽  
River Stretch ◽  
Ph Range ◽  
The Impact

The impact of partially treated wastewater on the water quality of Notwane river stretch in the Gaborone region of Botswana was investigated. Water samples collected at effluent discharge point and three other sampling sites downstream were analyzed for pH, temperature, Biological Oxygen Demand (BOD5), Ammonia-nitrogen (Ammonia-N) and Nitrate-nitrogen (Nitrate-N). Sampling was conducted bi-weekly between February 2013 and April 2013. The ranges of measured parameters were:  pH (7.6-8.5), temperature (22-23ºC), BOD5 (11.2-27.0 mg/l), Ammonia-N (2.4-60.5 mg/l), Nitrate-N (20.6-28.6 mg/l). Analysis of variance, Games-Howel multiple comparisons and Pearson correlation were used to separate variable means. The results signal river non-point pollution due to runoff inflow of organics mainly from land use and domestic waste dumping by nearby dwellings. Temperature, BOD5, and pH range values were all within the Botswana Bureau of Standards (BOBS) limit while the maximum Ammonia-N and Nitrate-N were above BOBS limit by 50.5 mg/l and 6.6 mg/l, respectively. Regulations on indiscriminate waste dumping and discharge standards adherence should be enforced.

Septage dewatering in vertical-flow constructed wetlands located in the tropics

2001 ◽  
Vol 44 (2-3) ◽  
pp. 181-188 ◽  
Author(s):  
T. Koottatep ◽  
C. Polprasert ◽  
N. T.K. Oanh ◽  
U. Heinss ◽  
A. Montangero ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Low Cost ◽  
Drainage System ◽  
Oxygen Demand ◽  
Free Water ◽  
Total Solid ◽  
Solid Loading ◽  
Flow Mode ◽  
Vertical Flow ◽  
N Removal

Constructed wetlands (CWs) have been proven to be an effective low-cost treatment system, which utilizes the interactions of emergent plants and microorganisms in the removal of pollutants. CWs for wastewater treatment are normally designed and operated in horizontal-flow patterns, namely, free-water surface or subsurface flow, while a vertical-flow operation is normally used to treat sludge or septage having high solid contents. In this study, three pilot-scale CW beds, each with a surface area of 25 m2, having 65 cm sand-gravel substrata, supported by ventilated-drainage system and planting with narrow-leave cattails (Typha augustifolia), were fed with septage collected from Bangkok city, Thailand. To operate in a vertical-flow mode, the septage was uniformly distributed on the surface of the CW units. During the first year of operation, the CWs were operated at the solid loading rates (SLR) and application frequencies of, respectively, 80-500 kg total solid (TS)/m2.yr and 1-2 times weekly. It was found that the SLR of 250 kg TS/m2.yr resulted in the highest TS, total chemical oxygen demand (TCOD) and total Kjeldahl nitrogen (TKN) removal of 80, 96 and 92%, respectively. The TS contents of the dewatered septage on the CW beds were increased from 1-2% to 30-60% within an operation cycle. Because of the vertical-flow mode of operation and with the effectiveness of the ventilation pipes, there were high degrees of nitrification occurring in the CW beds. The nitrate (NO3) contents in the CW percolate were 180-250 mg/L, while the raw septage had NO3 contents less than 10 mg/L. Due to rapid flow-through of the percolates, there was little liquid retained in the CW beds, causing the cattail plants to wilt, especially during the dry season. To reduce the wilting effects, the operating strategies in the second year were modified by ponding the percolate in the CW beds for periods of 2 and 6 days prior to discharge. This operating strategy was found beneficial not only for mitigating plant wilting, but also for increasing N removal through enhanced denitrification activities in the CW beds. During these 2 year operations, the dewatered septage was not removed from the CW beds and no adverse effects on the septage dewatering efficiency were observed.

scholarly journals Effect of corn cobs as external carbon sources on nitrogen removal in constructed wetlands treating micro-polluted river water

2019 ◽  
Vol 79 (9) ◽  
pp. 1639-1647 ◽  
Author(s):  
Lu-ji Yu ◽  
Tao Chen ◽  
Yanhong Xu
Keyword(s):  
Organic Carbon ◽  
River Water ◽  
Constructed Wetlands ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Flow Mode ◽  
Low Carbon ◽  
Polluted River ◽  
Corn Cobs

Abstract Micro-polluted river water is characterized as having limited biodegradability, low carbon to nitrogen ratio and little organic carbon supply, all of which makes it hard to further purify. Two bench scale constructed wetlands (CWs) with a horizontal subsurface flow mode were set up in the laboratory to evaluate their feasibility and efficiency on denitrification with and without corn cobs as external carbon sources. Micro-polluted river water was used as feed solution. The CW without corn cobs substrates possessed a good performance in removing chemical oxygen demand (COD, <40 mg/L) and ammonia nitrogen (NH3-N, <0.65 mg/L), but less efficiency in removing total nitrogen (TN) and nitrate nitrogen (NO3-N). In marked contrast, the CW with 1% (w/w) corn cobs substrates as external carbon sources achieved a significant improvement in the removal efficiency of TN (increased from 34.2% to 71.9%) and NO3-N (increased from 19% to 71.9%). The incorporation of corn cobs substrates did not cause any obvious increase in the concentrations of COD and NH3-N in the effluent. This improvement in the denitrification efficiency was owing to the released organic carbon from corn cobs substrates, which facilitated the growth of abundant microbes on the surface and pores of the substrate. The open area of the used corn chips is larger than that of the pristine ones, and corn cobs can continue to provide a carbon fiber source for denitrification.

Effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system

2012 ◽  
Vol 66 (6) ◽  
pp. 1220-1224
Author(s):  
Suwasa Kantawanichkul ◽  
Walaya Boontakhum
Keyword(s):  
Continuous Flow ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Synthetic Wastewater ◽  
Experimental Unit ◽  
Vertical Flow ◽  
Treatment Wetland ◽  
Wetland System ◽  
Flow Treatment

In this study, the effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system was investigated. The experimental unit was composed of four circular concrete tanks (1 m diameter and 80 cm deep), filled with gravel (1–2 cm) and planted with Cyperus alternifolius L. Synthetic wastewater with average chemical oxygen demand (COD) and ammonia nitrogen of 1,151 and 339 mg/L was fed into each tank. Different feeding and resting periods were applied: continuous flow (tank 1), 4 hrs on and 4 hrs off (tank 2), 1 hr on and 3 hrs off (tank 3) and 15 minutes on and 3 hrs 45 minutes off (tank 4). All four tanks were under the same hydraulic loading rate of 5 cm/day. After 165 days the reduction of total Kjeldahl nitrogen and ammonia nitrogen and the increase of nitrate nitrogen were greatest in tank 4, which had the shortest feeding period, while the continuous flow produced the lowest results. Effluent tanks 2 and 3 experienced similar levels of nitrification, both higher than that of tank 1. Thus supporting the idea that rapid dosing periods provide better aerobic conditions resulting in enhanced nitrification within the bed. Tank 4 had the highest removal rates for COD, and the continuous flow had the lowest. Tank 2 also exhibited a higher COD removal rate than tank 3, demonstrating that short dosing periods provide better within-bed oxidation and therefore offer higher removal efficiency.

scholarly journals Treatment of Leachate Using Up-Flow Anaerobic Sludge Blanket Reactors/Vertical Flow Subsurface Constructed Wetlands

2020 ◽  
Vol 27 (1) ◽  
pp. 129-137
Author(s):  
Şevket Tulun
Keyword(s):  
Total Nitrogen ◽  
Landfill Leachate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Organic Content ◽  
Ammonia Removal ◽  
Anaerobic Sludge ◽  
Vertical Flow ◽  
Physico Chemical ◽  
Anaerobic Sludge Blanket

AbstractThe composition of local solid waste consists mainly of biodegradable waste with high moisture and organic content. After being landfilled, the waste decomposes through a series of combined physico-chemical and biological processes, resulting in the generation of landfill leachate. Unless treated properly, the leachate poses a serious threat to the environment and to public health. In this study, the use of an engineered system consisting of an up-flow anaerobic sludge blanket reactor and a vertical flow subsurface constructed wetland for the treatment of landfill leachate was investigated. The leachate obtained from a landfill facility in Aksaray, Turkey was fed into both systems and laboratory tests showed that, over the 6-week study period, the systems were able to efficiently remove chemical oxygen demand (88.6 %) and total nitrogen (80.7 %). The results of this study suggested that Typha angustifolia significantly increased the removal of total nitrogen. The higher ammonia removal occurred in the anaerobic system and also the removal efficiency increased in planted bed, it is presumed to be the result of the ammonia nitrogen uptake by the roots of the plant.

Experiences from the full-scale implementation of a new two-stage vertical flow constructed wetland design

2013 ◽  
Vol 69 (2) ◽  
pp. 335-342 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Raimund Haberl
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Full Scale ◽  
Vertical Flow ◽  
Effluent Water ◽  
Two Stage ◽  
Vertical Flow Constructed Wetland ◽  
Hydraulic Load ◽  
Public Holidays

This paper describes the results of the first full-scale implementation of a two-stage vertical flow constructed wetland (CW) system developed to increase nitrogen removal. The full-scale system was constructed for the Bärenkogelhaus, which is located in Styria at the top of a mountain, 1,168 m above sea level. The Bärenkogelhaus has a restaurant with 70 seats, 16 rooms for overnight guests and is a popular site for day visits, especially during weekends and public holidays. The CW treatment system was designed for a hydraulic load of 2,500 L.d−1 with a specific surface area requirement of 2.7 m2 per person equivalent (PE). It was built in fall 2009 and started operation in April 2010 when the restaurant was re-opened. Samples were taken between July 2010 and June 2013 and were analysed in the laboratory of the Institute of Sanitary Engineering at BOKU University using standard methods. During 2010 the restaurant at Bärenkogelhaus was open 5 days a week whereas from 2011 the Bärenkogelhaus was open only on demand for events. This resulted in decreased organic loads of the system in the later period. In general, the measured effluent concentrations were low and the removal efficiencies high. During the whole period the ammonia nitrogen effluent concentration was below 1 mg/L even at effluent water temperatures below 3 °C. Investigations during high-load periods, i.e. events like weddings and festivals at weekends, with more than 100 visitors, showed a very robust treatment performance of the two-stage CW system. Effluent concentrations of chemical oxygen demand and NH4-N were not affected by these events with high hydraulic loads.

scholarly journals Effectiveness of septage pre-treatment in vertical flow constructed wetlands

2017 ◽  
Vol 76 (9) ◽  
pp. 2544-2553 ◽  
Author(s):  
Beata Karolinczak ◽  
Wojciech Dąbrowski
Keyword(s):  
Constructed Wetlands ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Vegetation Period ◽  
Ammonia Nitrogen ◽  
Vertical Flow ◽  
Municipal Wastewater Treatment ◽  
Vertical Flow Constructed Wetlands ◽  
Hydraulic Load ◽  
Pre Treatment

Abstract Septage is wastewater stored temporarily in cesspools. A periodic supply of its significant quantities to small municipal wastewater treatment plants (WWTPs) may cause many operational problems. In the frame of the research, it has been proposed to utilize vertical flow constructed wetlands for pre-treatment of septage prior to its input to the biological stage of a WWTP. The aim of the work was to assess the effectiveness of pre-treatment in relation to factors such as: seasonality, hydraulic load, pollutants load of the VF bed and interactions between these factors. The results proved that application of a VF bed to septage pre-treatment can significantly reduce the concentration of pollutants (biochemical oxygen demand (BOD5): 82%, chemical oxygen demand (COD): 82%, total suspended solids (TSS): 91%, total nitrogen (TN): 47%, ammonia nitrogen (NH4-N): 70%), and thus decrease the loading of the biological stage of a WWTP. The mathematical models of mass removal process were created. They indicate that in case of all analysed parameters, removed load goes up with the increase of load in the influent. However, with the increase of hydraulic load, a decrease of the removed BOD5, COD, TSS and total phosphorus, and in vegetation period an increase of TN, can be observed in terms of load. There are no statistically significant effects of seasonality.

Effect on Denitrification Efficiency in Alternating Process at Different C/N Ratio

2014 ◽  
Vol 1030-1032 ◽  
pp. 442-445
Author(s):  
Chun Di Gao ◽  
Wei Xiao Wang ◽  
Shi Xin Fan ◽  
Hao Li ◽  
Er Long Jiao
Keyword(s):  
Accumulation Rate ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Partial Nitrification ◽  
Biological Nitrogen Removal ◽  
Nitrite Accumulation ◽  
High Level ◽  
Biological Nitrogen ◽  
The Impact

Nitrification-denitrification biological nitrogen removal process has become the hotspot for the wastewater. During carbon/nitrogen (C/N) ratio was 1.16, 2.25, 4.07 and 6.20, the change of denitrification efficiency and the impact on the partial nitrification/denitrification was investigated. The results showed that removal rate of ammonia nitrogen was maintained in the high level, and was stable above 98% after C/N ratio higher than 1.16. With C/N ratio increased, the removal rate of chemical oxygen demand was increased about 20%, total nitrogen was increased from 54.9% to 84.6%. Simultaneously, after C/N ratio was higher than 4.07, the concentration of effluent TN was below 15 mg/L. Nitrite accumulation rate was maintained above 95%, the effect on partial nitrification was good, and the concentration of effluent nitrate was nearly 0, the best ratio of the C/N ratio was 4.07.

scholarly journals Development of Optimal Management Strategies for the Interception System Using River Water Quality Modeling

2018 ◽  
Vol 175 ◽  
pp. 03024
Author(s):  
Chen-Yao Ma ◽  
Yi-Chu Huang ◽  
Chih-Ming Kao
Keyword(s):  
Water Quality ◽  
Management Strategies ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Water Quality Modeling ◽  
Water Bodies ◽  
Quality Analysis ◽  
Quality Model ◽  
Quality Modeling ◽  
The Impact

This study adopted the water quality model [Water Quality Analysis Simulation Program (WASP)] to simulate and evaluate the impacts of the opening and closure of an interception system at the tributary of Love River on mainstream water quality. The gates were opened respectively for 4, 12, and 24 hours to assess the impact on biochemical oxygen demand (BOD) and ammonia nitrogen (NH3-N) in the water bodies of Love River. The WASP model was used to evaluate the self-purification capacity of the river. According to the results of the model estimation, it takes 5 days for NH3-N and BOD in the water bodies of Love River to return to normal and for the water to restore its original water quality after the closure of the Baozhu Ditch gate. Results of this study can be used as a reference for Love River watershed management, and the WASP modeling can be applied for decision makers to develop appropriate management strategies of the interception system.

Influence of Inoculum to Substrate Ratio on Solid Acidogenic Digestion with Pig Manure and Maize Straw

2012 ◽  
Vol 518-523 ◽  
pp. 223-228
Author(s):  
Lei Zhang ◽  
Lian Zhu Du ◽  
Wen Wen Cui ◽  
Ke Qiang Zhang
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Threshold Concentration ◽  
Pig Manure ◽  
Fermentation Products ◽  
Substrate Ratio ◽  
The Impact

A laboratory-scale study adopting mixture of manure and straw as substrate was carried out to elucidate the impact of inoculum to substrate ratio(ISR) on hydrolysis and acidification digestion with methanogenic effluent recycling. The chemical oxygen demand(COD), pH, and volatile fatty acids (VFAs) concentration were periodically analyzed in order to completely understand the digestion processing. In addition, ammonia-nitrogen was also monitored. The results showed that acetic acid was dominant in fermentation products of different ISRs and the percentage of acetic acid in total volatile fatty acids (TVFAs) increased with the increase of ISR, and acetic acid accounted to 68.74%, 72.02%, 75.89% and 86.65% of TVFAs when ISR were 15%, 25%, 35% and 50%. Propionic acid accounted for 6.68%, 5.92%, 5.54% and 2.67% of TVFAs produced, and the concentration was less than 0.60 g/L. The possible inhibition by free ammonia was null since the values were far below the threshold concentration reported in other literatures, but the potential inhibition maybe happen after long-term recycling of methanogenic effluent.

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