scholarly journals Denitrifying Bioreactor Woodchip Recharge: Media Properties after Nine Years

2020 ◽  
Vol 63 (2) ◽  
pp. 407-416 ◽  
Author(s):  
Gary W. Feyereisen ◽  
Christopher Hay ◽  
Ulrike W. Tschirner ◽  
Keegan Kult ◽  
Niranga M. Wickramarathne ◽  
...  
Keyword(s):  
Preferential Flow ◽  
Nitrate Removal ◽  
Drainage System ◽  
Drainage Water ◽  
Tracer Testing ◽  
Batch Tests ◽  
Design Life ◽  
Lack Of Information ◽  
N Removal ◽  
Physical Changes

HighlightsWood media harvested from a nine-year-old denitrifying bioreactor were evaluated.Media physical changes had multiple causes and effects.Impacts of the physical changes may have been exacerbated by development of preferential flow.LCIs > 0.6 showed C quality declined but media still supported N removal.Abstract. There is a lack of information on denitrifying bioreactors treating subsurface drainage water at the end of their initial design life due to the relative newness of the technology and the relatively long estimated life. A denitrifying bioreactor (15 m L × 7.6 m W × 1.1 m D) installed in August 2008 in Greene County, Iowa, was recharged with new woodchips in November 2017 (age 9.25 years), providing the opportunity to evaluate the properties of the wood media at the end of design life. The objective was to pair a battery of physical, chemical, and nitrate-N removal tests on the wood media harvested from the bioreactor with field observations to assess likely reasons why denitrifying bioreactors treating tile drainage may need to be recharged. The two types of wood media harvested from the bioreactor (termed woodchips and mixed shreds) had median particle sizes (D50) of 12.1 and 7.7 mm, respectively, and saturated hydraulic conductivities of 4.2 ±3.0 and 3.1 ±1.0 cm s-1 (mean ± standard deviation), which were within the range of reported values for woodchips, albeit at the low end. The wood media carbon content and quality had degraded (e.g., lignocellulose indices of 0.63 to 0.74, nearing the range of decomposition stabilization), although batch tests suggested the robustness of wood as a carbon source to support nitrate removal (e.g., 65% nitrate concentration reduction in drainage water). Woodchip degradation along with sedimentation from the drainage system likely reduced conductivities over time. Development of preferential flow paths through the bioreactor was indicated by low bioreactor outflow rates (i.e., reduced permeability) and reduced hydraulic efficiency based on conservative tracer testing. These changes in media properties and linked impacts resulted in the need to recharge this bioreactor after nine years. Keywords: Denitrifying bioreactor, Hydraulic conductivity, Nitrate, Water quality.

scholarly journals An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3390
Author(s):  
Hui Zhang ◽  
Lin Song ◽  
Xiaolin Chen ◽  
Pengcheng Li
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Nitrate Removal ◽  
Denitrifying Bacteria ◽  
Soil Salinization ◽  
Nitrate Content ◽  
Weak Efficiency ◽  
N Accumulation ◽  
N Removal ◽  
Intensively Managed

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.

Nitrate Removal of Drainage Water with Barley Straw as a Bioreactor Filter

2010 ◽  
Author(s):  
Seyyed Ebrahim Hashemi ◽  
Manouchehr Heidarpour ◽  
Behrouz Mostafazadeh-Fard ◽  
Ali Madani ◽  
Sayed-Farhad Mousavi ◽  
...  
Keyword(s):  
Nitrate Removal ◽  
Drainage Water ◽  
Barley Straw

Evaluation of tephra for removing phosphorus from dairy farm drainage waters

Soil Research ◽  
2008 ◽  
Vol 46 (7) ◽  
pp. 542 ◽  
Author(s):  
J. A. Hanly ◽  
M. J. Hedley ◽  
D. J. Horne
Keyword(s):  
Field Study ◽  
Removal Efficiency ◽  
Drainage System ◽  
Dairy Farm ◽  
Drainage Water ◽  
Control Treatment ◽  
Drainage Systems ◽  
P Adsorption ◽  
Drainage Waters ◽  
P Removal

Research was conducted in the Manawatu region, New Zealand, to investigate the ability of Papakai tephra to remove phosphorus (P) from dairy farm mole and pipe drainage waters. The capacity of this tephra to adsorb P was quantified in the laboratory using a series of column experiments and was further evaluated in a field study. In a column experiment, the P adsorption capabilities of 2 particle size factions (0.25–1, 1–2 mm) of Papakai tephra were compared with that of an Allophanic Soil (Patua soil) known to have high P adsorption properties. The experiment used a synthetic P influent solution (12 mg P/L) and a solution residence time in the columns of c. 35 min. By the end of the experiment, the 0.25–1 mm tephra removed an estimated 2.6 mg P/g tephra at an average P removal efficiency of 86%. The 1–2 mm tephra removed 1.6 mg P/g tephra at an average removal efficiency of 58%. In comparison, the Patua soil removed 3.1 mg P/g soil at a P removal efficiency of 86%. Although, the Patua soil was sieved to 1–2 mm, this size range consisted of aggregates of finer particles, which is likely to have contributed to this material having a higher P adsorbing capacity. A field study was established on a Pallic Soil, under grazed dairy pastures, to compare drainage water P concentrations from standard mole and pipe drainage systems (control) and drainage systems incorporating Papakai tephra. The 2 tephra treatments involved filling mole channels with 1–4 mm tephra (Mole-fill treatment) or filling the trench above intercepting drainage pipes with ‘as received’ tephra (Back-fill treatment). Over an entire winter drainage season, the quantity of total P (TP) lost from the control treatment drainage system was 0.30 kg P/ha. The average TP losses for the Mole-fill and the Back-fill treatments were 45% and 47% lower than the control treatment, respectively.

scholarly journals Denitrification-Potential Evaluation and Nitrate-Removal-Pathway Analysis of Aerobic Denitrifier Strain Marinobacter hydrocarbonoclasticus RAD-2

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1298 ◽  
Author(s):  
Dedong Kong ◽  
Wenbing Li ◽  
Yale Deng ◽  
Yunjie Ruan ◽  
Guangsuo Chen ◽  
...  
Keyword(s):  
Nitrate Removal ◽  
Aerobic Denitrification ◽  
Transcriptional Level ◽  
16S Rrna Sequence ◽  
Recirculating Aquaculture ◽  
N Removal ◽  
Denitrification Reactor ◽  
Potential Alternative ◽  
Marinobacter Hydrocarbonoclasticus

An aerobic denitrifier was isolated from a long-term poly (3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV-supported denitrification reactor that operated under alternate aerobic/anoxic conditions. The strain was identified as Marinobacter hydrocarbonoclasticus RAD-2 based on 16S rRNA-sequence phylogenetic analysis. Morphology was observed by scanning electron microscopy (SEM), and phylogenetic characteristics were analyzed with the API 20NE test. Strain RAD-2 showed efficient aerobic denitrification ability when using NO3−-N or NO2−-N as its only nitrogen source, while heterotrophic nitrification was not detected. The average NO3−-N and NO2−-N removal rates were 6.47 mg/(L·h)and 6.32 mg/(L·h), respectively. Single-factor experiments indicated that a 5:10 C/N ratio, 25–40 °C temperature, and 100–150 rpm rotation speed were the optimal conditions for aerobic denitrification. Furthermore, the denitrifying gene napA had the highest expression on a transcriptional level, followed by the denitrifying genes nirS and nosZ. The norB gene was found to have significantly low expression during the experiment. Overall, great aerobic denitrification ability makes the RAD-2 strain a potential alternative in enhancing nitrate management for marine recirculating aquaculture system (RAS) practices.

Effect of controlled drainage and tillage on soil structure and tile drainage nitrate loss at the field scale

1998 ◽  
Vol 38 (4-5) ◽  
pp. 103-110 ◽  
Author(s):  
C. S. Tan ◽  
C. F. Drury ◽  
M. Soultani ◽  
I. J. van Wesenbeeck ◽  
H. Y. F. Ng ◽  
...  
Keyword(s):  
Soil Structure ◽  
Conservation Tillage ◽  
Drainage System ◽  
Conventional Tillage ◽  
Drainage Water ◽  
Tile Drainage ◽  
No Tillage ◽  
Controlled Drainage ◽  
Nitrate Loss ◽  
Free Drainage

Conservation tillage has become an attractive form of agricultural management practices for corn and soybean production on heavy textured soil in southern Ontario because of the potential for improving soil quality. A controlled drainage system combined with conservation tillage practices has also been reported to improve water quality. In Southwestern Ontario, field scale on farm demonstration sites were established in a paired watershed (no-tillage vs. conventional tillage) on clay loam soil to study the effect of tillage system on soil structure and water quality. The sites included controlled drainage and free drainage systems to monitor their effect on nitrate loss in the tile drainage water. Soil structure, organic matter content and water storage in the soil profile were improved with no-tillage (NT) compared to conventional tillage (CT). No-tillage also increased earthworm populations. No-tillage was found to have higher tile drainage volume and nitrate loss which were attributed to an increase in soil macropores from earthworm activity. The controlled drainage system (CD) reduced nitrate loss in tile drainage water by 14% on CT site and 25.5% on NT site compared to the corresponding free drainage system (DR) from May, 1995 to April 30, 1997. No-tillage farming practices are definitely enhanced by using a controlled drainage system for preventing excessive nitrate leaching through tile drainage. Average soybean yields for CT site were about 12 to 14% greater than the NT site in 1995 and 1996. However, drainage systems had very little effect on soybean yields in 1995 and 1996 due to extremely dry growing seasons.

scholarly journals Designing catchment area for water resources management in ITS campus

2018 ◽  
Vol 48 ◽  
pp. 05002
Author(s):  
Joni Hermana ◽  
Irhamah ◽  
Dian Saptarini ◽  
Tatas
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Ground Water ◽  
Catchment Area ◽  
Drainage System ◽  
Coastal Region ◽  
Building Blocks ◽  
Drainage Water ◽  
Environmental Damage ◽  
High Level

Institut Teknologi Sepuluh Nopember (ITS) Campus, with the area of 167.4 Ha, is located within Surabaya coastal region in the eastern part of Java Island. It has initial characteristic with wetlands and swamps ecosystem. As a science and technological university, with the main acitivities in teaching, experimental laboratory works, and student activities, ITS is, currently, using ± 49% of its total vast area as building blocks for supporting academic facilities. Being a campus in a coastal zone, the commonly main problems are high porous soil, brackish surface water, high level of ground water, an obstructed drainage tendency because of delicate slant, and low catchment capability. This paper provides an action program on how ITS manage water resources within campus area in order to suppress environmental damage. Many steps had been taken into account for water catchment role, for instance: maintaining the catchment area on the main ITS master plan, planning catchment pond, surface water stabilization by preventing ground water usage, interrupting drainage water flow as being directly discharged into the city drainage system, rain water harvesting, and also designing floating floor for buildings.

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.

Denitrification with isopropanol as a carbon source in a biofilm system

1994 ◽  
Vol 30 (11) ◽  
pp. 69-78 ◽  
Author(s):  
Yongwoo Hwang ◽  
Hiroshi Sakuma ◽  
Toshihiro Tanaka
Keyword(s):  
Carbon Source ◽  
Nitrate Removal ◽  
Growth Yield ◽  
Pilot Scale ◽  
Denitrification Rate ◽  
Hydrogen Donor ◽  
Microbial Oxidation ◽  
Biological Denitrification ◽  
Batch Tests

Several batch tests and pilot-scale investigations on biological denitrification with isopropanol were performed. Isopropanol was converted to acetone by microbial oxidation during denitrification. Isopropanol itself little contributed to denitrification in practice while the converted acetone played a role of a main hydrogen donor. A larger quantity of nitrite intermediate was formed by using methanol compared to the case of isopropanol. The measured requirement of isopropanol was 2.0 mg mg−1 NO3-N, and was 2/3 of methanol. The oxygen equivalent of isopropanol for nitrate removal was almost the same as that of methanol. The denitrifier net growth yield for isopropanol was greater than for methanol. In order to maximize the denitrification rate, it is essential to convert isopropanol to acetone rapidly by accurate dosing for nitrogen load because the denitrification rate was accelerated by using acetone only. Excessive dose of isopropanol can cause a decrease in the denitrification rate as well as an increase of BOD in the effluent.

scholarly journals Antarctic subglacial lakes drain through sediment-floored canals: theory and model testing on real and idealized domains

2017 ◽  
Vol 11 (1) ◽  
pp. 381-405 ◽  
Author(s):  
Sasha P. Carter ◽  
Helen A. Fricker ◽  
Matthew R. Siegfried
Keyword(s):  
Distributed System ◽  
Process Model ◽  
Ice Sheet ◽  
Drainage System ◽  
Drainage Water ◽  
Process Models ◽  
Altimeter Data ◽  
Laser Altimeter ◽  
Ice Stream ◽  
Subglacial Lakes

Abstract. Over the past decade, satellite observations of ice surface height have revealed that active subglacial lake systems are widespread under the Antarctic Ice Sheet, including the ice streams. For some of these systems, additional observations of ice-stream motion have shown that lake activity can affect ice-stream dynamics. Despite all this new information, we still have insufficient understanding of the lake-drainage process to incorporate it into ice-sheet models. Process models for drainage of ice-dammed lakes based on conventional R-channels incised into the base of the ice through melting are unable to reproduce the timing and magnitude of drainage from Antarctic subglacial lakes estimated from satellite altimetry given the low hydraulic gradients along which such lakes drain. We have developed an alternative process model, in which channels are mechanically eroded into the underlying deformable subglacial sediment. When applied to the known active lakes of the Whillans–Mercer ice-stream system, the model successfully reproduced both the inferred magnitudes and recurrence intervals of lake-volume changes, derived from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data for the period 2003–2009. Water pressures in our model changed as the flood evolved: during drainage, water pressures initially increased as water flowed out of the lake primarily via a distributed system, then decreased as the channelized system grew, establishing a pressure gradient that drew water away from the distributed system. This evolution of the drainage system can result in the observed internal variability of ice flow over time. If we are correct that active subglacial lakes drain through canals in the sediment, this mechanism also implies that active lakes are typically located in regions underlain by thick subglacial sediment, which may explain why they are not readily observed using radio-echo-sounding techniques.

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