Nitrification in reed beds - capacity and potential control methods

2002 ◽  
Vol 46 (6-7) ◽  
pp. 363-370 ◽  
Author(s):  
K. Kayser ◽  
S. Kunst ◽  
G. Fehr ◽  
H. Voermanek

Vertical-flow reed beds (VFBs) are known to be very effective regarding nitrification. However, a generally accepted design formula for dimensioning reed beds for a controlled nitrification process has still not been found. Especially for the purpose of nitrification a vertical-flow reed bed (VFB) has been installed following an existing unaerated pond-system. The paper presents the results concerning the limits of the VFB's performance as well as the main factors influencing the nitrification process gained by balancing the conversion rates under different loads. Even under high loads the VFB provides an excellent nitrification performance, which is mainly influenced by the wastewater temperature. The ammonia oxidation rate is about 90% at temperatures over 10°C; at temperatures below 5°C the average nitrification rate is still approximately 50%. The hydraulic load and the TKN load have almost no impact on this efficiency (the maximum load has been: 180 mm/d, 7.1 g TKN/(m2*d)). The redox potenial, which is continuously measured in the effluent of the reed bed, proved to be dependent on the current nitrification performance and the oxygen supply of the VFB, and therefore appears to be a suitable control parameter for the operation of VFBs.

2000 ◽  
Vol 41 (1) ◽  
pp. 57-63 ◽  
Author(s):  
S. Vandaele ◽  
C. Thoeye ◽  
B. Van Eygen ◽  
G. De Gueldre

In Flanders (Belgium) an estimated 15% of the population will never be connected to a central wastewater treatment plant (WWTP). Small WWTPs can be a valuable option. Aquafin bases the decision to build SWWTPs on a drainage area study. To realise an accelerated construction the process choice is made accordingly to a standard matrix, which represents the different technologies in function of the size and the effluent consents. A pilot scale constructed two-stage reed bed is used to optimise the concept of the reed beds. The concept consists of a primary clarifier, two parallel vertical flow reed beds followed by a sub-surface flow reed bed. The removal efficiency of organic pollutants is high (COD: 89%, BOD: 98%). Phosphorus removal is high at the start-up but diminishes throughout the testing period (from 100% to 71% retention after 7 months). Nitrogen removal amounts to 53% on average. Nitrification is complete in summer. Denitrification appears to be the limiting factor. In autumn leakage of nitrogen is assumed. Removal efficiency of pathogens amounts to almost 99%. Clogging forms a substantial constraint of the vertical flow reed bed. Problems appear to be related with presettlement, feed interval and geotextile.


2014 ◽  
Vol 11 (7) ◽  
pp. 2083-2098 ◽  
Author(s):  
S. S.-Y. Hsiao ◽  
T.-C. Hsu ◽  
J.-w. Liu ◽  
X. Xie ◽  
Y. Zhang ◽  
...  

Abstract. Nitrification is a series of processes that oxidizes ammonia to nitrate, which contributes to hypoxia development in coastal oceans, especially in eutrophicated regions. The nitrification rate of bulk water (NRb) and particle free water (NRpf, particle > 3 μm eliminated) were determined along the Chang Jiang River plume in August 2011 by nitrogen isotope tracer technique. Measurements of dissolved oxygen (DO), community respiration rate (CR), nutrients, dissolved organic nitrogen (DON), total suspended matter (TSM), particulate organic carbon/nitrogen (POC / PON), acid-leachable iron and manganese on suspended particles and both archaeal and β-proteobacterial ammonia monooxygenase subunit A gene (amoA) abundance on size-fractioned particles (> 3 μm and 0.22–3 μm) were conducted. The NRb ranged from undetectable up to 4.6 μmol L−1 day−1, peaking at a salinity of ~ 29. NRb values were positively correlated with ammonium concentration, suggesting the importance of substrate in nitrification. In the river mouth and the inner plume, NRb was much higher than NRpf, indicating that the nitrifying microorganism is mainly particle associated, which was supported by its significant correlation with amoA gene abundance and TSM concentration. The estimated oxygen demands of nitrification accounted for 0.32 to 318% of CR, in which 50% samples demanded more oxygen than that predicted by by the Redfield model (23%), indicating that oxygen might not be the sole oxidant though DO was sufficient (> 58 μmol kg−1) throughout the observation period. The excess nitrification-associated oxygen demand (NOD) showed a tendency to occur at lower DO samples accompanied by higher acid-leachable Fe / Mn, which implied reactive Fe3+ / Mn4+ may play a role as oxidant in the nitrification process. Stoichiometric calculation suggested that reactive Fe on particles was 10 times the oxidant demand required to complete ammonia oxidation in the entire plume. The potential involvement of reactive iron and manganese in the nitrification process in oxygenated water further complicated nitrogen cycling in the turbid river plume.


1997 ◽  
Vol 35 (5) ◽  
pp. 223-230 ◽  
Author(s):  
Monika Schönerklee ◽  
Ferdinand Koch ◽  
Reinhard Perfler ◽  
Raimund Haberl ◽  
Johannes Laber

In Strengberg, Lower Austria, a vertical flow reed bed system (gravel/sand) was chosen as a new type of tertiary treatment which was designed as a full scale pilot plant with various possibilities of operational use. The surface of the vertical flow pilot plant amounts to about 600 m2 and is divided into four beds whereby two different depths of substrate are used. The application of the conventional plant effluent is carried out in intermittent flushes and at changeable time intervals. Final nitrification and partial denitrification and elimination of phosphorus are the main goals to be achieved. In the framework of the present research project the load limits will be determined by gradually raising the influent load. The efficiency and operational reliability within the whole year period (summer/winter) are considered to be an important factor for establishing general dimensioning approaches. The pilot plant has been in operation for more than one year now. Different operational stages up to a hydraulic load of 1.3 m2.p.e.−1 (i.e. 0.75 m2.p.e.−1) were carried out. The average chemical oxygen demand (COD) of the reed bed effluents varied from 1 to 20 mg.1−1. Not surprisingly the ammonium (NH4-N) results showed more variation. Results, thus far, indicate NH4-N removal efficiencies between 40% and 90%.


1999 ◽  
Vol 40 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Paul Cooper ◽  
Paul Griffin ◽  
Stuart Humphries ◽  
Adrian Pound

The design of vertical-flow (VF) reed beds is reviewed and the performance of the few worldwide existing hybrid systems, combining both horizontal- and vertical-flow beds, is assessed. Horizontal-flow (HF) beds are good for suspended solids removal and will remove BOD5 up to a set loading. Vertical-flow beds can achieve BOD5 removal at much higher loading rates and they are capable of complete nitrification as tertiary or secondary treatment systems. It is possible to achieve biological denitrification in horizontal-flow beds. By combining horizontal- and vertical-flow systems in the appropriate process sequence it is thus possible to produce a system which removes BOD5, TSS and achieves complete nitrification as well as substantial removal of nitrate and hence a lowered Total N. The paper discusses the possible process options for combining horizontal- and vertical-flow systems. One example of these systems will be described in more detail. This is a flexible hybrid system being built by Severn Trent Water. Designed to treat the flow for a small village with a population of 129 it will have vertical-flow beds followed by horizontal-flow beds. The design allows for flexibility such that the size of the vertical-flow and horizontal-flow stages can be altered (for experimental purposes) to allow the design arrangement to be stressed and performance evaluated with the intention of defining the optimum loading rates for each of the stages. The same site also has sludge drying reed beds for treating the primary sludge.


2005 ◽  
Vol 51 (9) ◽  
pp. 177-184 ◽  
Author(s):  
K. Kayser ◽  
S. Kunst

Vertical-flow reed beds (VF) with intermittent feeding are extremely reliable regarding aerobic processes. For a save operation with high nitrification rates and without soil clogging it is essential to preserve aerobic conditions in the filter. The challenge is to keep aerobic conditions in the filter without oversizing the system (economical aspects). It is very difficult to determine the current oxygen content in the filters because it ultimately results from complex interactions of a large number of different influencing parameters such as loading rate, degree of clogging, temperature, and hydraulic behaviour of the reed bed. To gain better knowledge of this complex system, different tests and examinations were carried out over several years. Focusing on the questions of identification and the description of conversion and transport processes (water/gas), a full-scale treatment plant under clogged and non-clogged conditions was investigated in detail. Additionally soil column test were carried out. The results make it possible to describe some of the processes and their interactions in the filter body. Recommendations for a safe and controlled operation can be derived.


1995 ◽  
Vol 32 (3) ◽  
pp. 339-348 ◽  
Author(s):  
M. B. Green ◽  
J. Upton

Reed bed treatment is put in the context of a major water company’s need to provide reliable, high quality, effluents from small sewage treatment works whilst seeking to minimise running costs. Design and operational information is given for reed bed applications in Severn Trent Water. Performance details are provided for application to secondary, tertiary and storm overflow treatment. The results give particular confidence in the system’s ability to deliver very high quality effluents when used for tertiary treatment, the company’s biggest application. Reed beds work well against less demanding criteria for secondary treatment at small sites and show great promise for storm overflow treatment.


1994 ◽  
Vol 30 (4) ◽  
pp. 47-56 ◽  
Author(s):  
O. Sinkjær ◽  
L. Yndgaard ◽  
P. Harremoës ◽  
J. L. Hansen

Pilot plant experiments have been performed over a period of four years in order to establish an experimental basis for the upgrading of the treatment plants of the city of Copenhagen to nitrogen removal. The design chosen is based on the alternating mode of operation. Nitrification rates have been determined in batch tests on activated sludge extracted from the pilot plants and through the measuring of transient concentrations during the alternating mode of operation in the aerobic reactor. The data have been nonnalised to standard conditions by correcting them according to the kinetic theory. By monitoring the normalised nitrification rate it could be established that the nitrification process was occasionally inhibited. The aerobic sludge age required to maintain nitrification has been estimated. A specific evaluation has been made of the sensitivity of the required sludge age to the oxygen concentration and temperature.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.


2009 ◽  
Vol 60 (11) ◽  
pp. 2759-2766 ◽  
Author(s):  
C. Murphy ◽  
P. Hawes ◽  
D. J. Cooper

The ability of reed beds to remove significant levels of metals from effluent streams is well cited in the literature. Various methods of removal have been postulated and demonstrated including physical methods such as filtration and settlement, precipitation when the metal is present as a salt and adsorption to organic species or take up by macrophytes when the metal is in a soluble or ionic form. Consequently, reed beds have been used in a variety of applications for metal removal in water treatment processes. The distillation process for whisky generates an effluent containing a significant amount of copper which is scoured from the copper stills during the process and cleaning operations. High soluble copper concentrations can breach discharge consents. A horizontal subsurface flow reed bed system has been designed and installed for copper removal at a distillery in Scotland. This paper presents the findings of the literature search, outlines the design of the bed and reviews the performance results.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 353-360 ◽  
Author(s):  
L. Davison ◽  
T. Headley ◽  
M. Edmonds

This paper summarises the results of studies on four subsurface flow wetlands (reed beds) located in the moist sub-tropical north eastern corner of the Australian state of New South Wales. The reed beds, which are subjected to a variety of effluent types, all have a gravel substrate planted with Phragmites australis. All four units were found to maintain satisfactory treatment performance year round. Mean removal efficiencies ranged from 56% to 90% (SS), 70% to 93% (BOD), 38% to 66% (TN), 87% to 99.8% (Faecal coliforms), and 42% to 70% (TP - with one seasonal result of 0% for the eight year old unit) for the four reed beds. After eight years in operation the oldest reed bed was showing signs of phosphorus saturation with outlet TP concentrations exceeding inlet concentrations on some occasions. The youngest reed bed studied appeared to be operating efficiently after five months. A summer water balance on one of the reed beds revealed an average crop factor of 1.6 and a moisture loss to atmosphere of 40% of influent flow. Treatment performance (particularly for TN and SS) was found to be negatively correlated with rainfall during one study. The paper discusses the implications of the above results for on-site system designers and regulators and identifies areas for further investigation.


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