Design of a Hybrid Reed Bed System to Achieve Complete Nitrification and Denitrification of Domestic Sewage

1999 ◽  
Vol 40 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Paul Cooper ◽  
Paul Griffin ◽  
Stuart Humphries ◽  
Adrian Pound
Keyword(s):  
Horizontal Flow ◽  
Vertical Flow ◽  
Total N ◽  
Reed Beds ◽  
Loading Rates ◽  
Flow Systems ◽  
Reed Bed ◽  
And Performance ◽  
Sludge Drying ◽  
Complete Nitrification

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.

A Review of the Design and Performance of Vertical-flow and Hybrid Reed Bed Treatment Systems

1999 ◽  
Vol 40 (3) ◽  
pp. 1-9 ◽  
Author(s):  
Paul Cooper
Keyword(s):  
Oxygen Transfer ◽  
Alternative Methods ◽  
Horizontal Flow ◽  
Vertical Flow ◽  
Reed Bed ◽  
And Performance ◽  
Oxygen Transfer Capacity

The paper reviews the different options for the combination of vertical- and horizontal-flow beds used in hybrid reed bed/wetland systems. The design and performance of these systems are briefly described. The importance of the oxygen transfer capacity of the different arrangements to their performance and their size is discussed. Alternative methods for denitrification are briefly described.

Reed bed treatment systems for sewage treatment in the United Kingdom - the first 10 years’ experience

1995 ◽  
Vol 32 (3) ◽  
pp. 317-327 ◽  
Author(s):  
P. Cooper ◽  
B. Green
Keyword(s):  
Root Zone ◽  
Sewage Treatment ◽  
Horizontal Flow ◽  
Water Industry ◽  
Soil Systems ◽  
Design Changes ◽  
Flow Systems ◽  
Group A ◽  
Reed Bed ◽  
The Uk

The UK Water Industry first became interested in Reed Bed Treatment Systems for sewage in 1985. Early problems were experienced with soil-based horizontal-flow systems of the Root Zone type. The problems were overcome by national co-ordination of a development programme and international co-operation by an EC Expert Contact Group. A number of different types of systems have now been developed and the systems are now being accepted. The paper reviews the development of these systems for secondary and tertiary treatment and nitrification and mentions development of systems for other forms of treatment. The design changes made to overcome the problems are described. These include the gradual move to the use of gravel-based systems because of the difficulty experienced with over-land flow in the soil systems. The sizing of the systems is described together with performance data for the original horizontal-flow and the more recently developed vertical-flow systems. Treatment at secondary and tertiary levels is illustrated and the potential for nitrification. Early problems with reed growth have been overcome by planting with port-grown seedlings. After 10 years the process is generally accepted by the Water Industry as an appropriate treatment for villages and there are now between 200 and 300 systems in operation.

Small wastewater treatment plants in Flanders (Belgium): standard approach and experiences with constructed reed beds

2000 ◽  
Vol 41 (1) ◽  
pp. 57-63 ◽  
Author(s):  
S. Vandaele ◽  
C. Thoeye ◽  
B. Van Eygen ◽  
G. De Gueldre
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Surface Flow ◽  
Limiting Factor ◽  
Vertical Flow ◽  
Reed Beds ◽  
Reed Bed

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.

Investigations on phosphorus retention in subsurface flow constructed wetlands

2003 ◽  
Vol 48 (5) ◽  
pp. 67-74 ◽  
Author(s):  
H. Rustige ◽  
I. Tomac ◽  
G. Höner
Keyword(s):  
Constructed Wetlands ◽  
Warm Season ◽  
Reed Beds ◽  
Loading Rates ◽  
Output Concentration ◽  
Reed Bed ◽  
Performance Rate ◽  
Filter Bed ◽  
Positive Effect ◽  
Small Positive Effect

62 SSF sand-based constructed wetlands in Germany, Austria and Switzerland have been evaluated for their phosphorus performance. In addition intensive investigations on the removal of phosphorus and its accumulation within the filter bed were conducted at five wetlands. For the performance of horizontal flow (HF) reed beds a regression equation could be derived. This was not possible for vertical flow (VF) reed beds. The best removal efficiency was observed from HF systems with hydraulic loading rates of 10 mm d-1 or less. 50 percent of all investigated HF wetlands had an average P output concentration of less than 2.1 mg l-1 in comparison to 3.3 mg l-1 of VF wetlands. Saturation, seasonal and redox effects could be derived from time series analysis of the performance rate and further investigations of a well monitored VF reed bed. The retention of phosphorus was highest during the warm season. A small positive effect on phosphorus removal was observed with intermittent low redox levels. Soil analyses showed the highest accumulation of P within the influent zone of either HF or VF wetlands.

Characteristics of Sludge Moisture Content Variation in Sludge Drying Reed Beds

2015 ◽  
Vol 768 ◽  
pp. 515-519
Author(s):  
Xin Nan Deng ◽  
Yu Bo Cui ◽  
Wei Gao ◽  
Rui Chen
Keyword(s):  
Moisture Content ◽  
Pilot Scale ◽  
Coarse Sand ◽  
Reed Beds ◽  
Conventional Drying ◽  
The Media ◽  
The Difference ◽  
Reed Bed ◽  
Sludge Drying ◽  
Media Layer

Sludge moisture content was investigated at different stages during the test. Pilot-scale sludge drying bed and sludge drying reed beds had the same size of 3 m×1 m×1.3 m, and the bed height consisted of a 65 cm media layer and a 65 cm extra height. The media layer is filled with slag (20 cm), gravel (20 cm), coarse sand (5 cm) and quartz sand (24.5 cm) from the bottom in turn. Unit 1 was a conventional sludge drying bed, unit 2 was a sludge drying reed bed. Unit 1 and unit 2 had ventilation pipes which were mounted on the drainage pipes. Unit 3 was a sludge drying reed bed without ventilation pipe. The waste activated sludge was feed into the three units periodically during the experiment. The experiment investigated the sludge moisture content. At the end of the operation, the sludge moisture content in three units decreased by 18.52%, 22.37%, and 20.68%, respectively. It was found that the dewatering effect of the sludge drying reed bed was better than the conventional drying bed. The effect of plant growth on sludge dewatering is greater than the ventilation, but the difference was not significant.

Greenhouse gas emissions from sludge treatment reed beds

2015 ◽  
Vol 71 (7) ◽  
pp. 1011-1018 ◽  
Author(s):  
Yubo Cui ◽  
Shunli Zhang ◽  
Zhaobo Chen ◽  
Rui Chen ◽  
Xinnan Deng
Keyword(s):  
Co2 Emission ◽  
Ch4 Emission ◽  
Gas Emission ◽  
Sludge Treatment ◽  
Reed Beds ◽  
Volatile Solids ◽  
Gas Fluxes ◽  
Reed Bed ◽  
Sludge Drying ◽  
Transparent Chamber

Sludge treatment reed bed systems (STRBs) are considered as an alternative technology for surplus sludge treatment. Organic matter is decomposed by various microbial reactions, resulting in gases such as CO2 and CH4 emitting into the atmosphere. The aim of this study is to investigate gas emission from STRBs. The static transparent chamber was adopted to measure gas emission; it allows sunlight to enter and plants to photosynthesise. The comparison of total solids and volatile solids showed STRBs have a higher efficiency in dewatering and mineralization than a conventional unplanted sludge drying bed (USDB). The CO2 emission ranged from 28.68 to 100.42 g CO2 m−2 d−1 in USDB, from 16.48 to 65.18 g CO2 m−2 d−1 in STRBs; CH4 emission ranged from 0.26 to 0.99 g CH4 m−2 d−1 in USDB, from 0.43 to 1.95 g CH4 m−2 d−1 in STRBs. Both gas fluxes decreased towards the end of vegetation and reached the highest rates during the hot and dry summer. After the system was loaded by sludge, the fluxes of CO2 and CH4 significantly decreased in the USDB, whereas they increased in STRBs. In terms of CO2 equivalent, the global warming potential of CH4 was 13.13 g CO2eq m−2 d−1 and 15.02 g CO2eq m−2 d−1 in USDB and STRBs, respectively.

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
Keyword(s):  
Ammonia Oxidation ◽  
Maximum Load ◽  
Nitrification Rate ◽  
Vertical Flow ◽  
Reed Beds ◽  
Potential Control ◽  
Conversion Rates ◽  
Nitrification Process ◽  
Hydraulic Load ◽  
Reed Bed

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.

The design and performance of a nitrifying vertical-flow reed bed treatment system

1997 ◽  
Vol 35 (5) ◽  
pp. 215-221 ◽  
Author(s):  
Paul Cooper ◽  
Mark Smith ◽  
Henrietta Maynard
Keyword(s):  
Nitrate Solution ◽  
Treatment System ◽  
Vertical Flow ◽  
Biological Filter ◽  
Ammonium Nitrate Solution ◽  
Reed Bed ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance

The paper describes the design, construction and the monitoring of a vertical-flow Reed Bed Treatment System (RBTS) which achieves tertiary nitrification of the effluent from a biological filter, treating the sewage flow from a population of about 200 people. It treats the flows from toilets, kitchen laboratories and a saline wastewater. The RBTS system takes effluent from an old biological filter and produces a nitrified effluent from a two-stage intermittently-dosed system. The paper shows the long-term performance of the system over a 4 year period and also describes experiments to assess the nitrification performance using a step-feed of ammonium nitrate solution. The system shows a removal of 8-13 g NH4-N/m3 of bed day. The design basis is shown and the operational features described.

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