A review of the design and performance of vertical-flow and hybrid reed bed treatment systems

1999 ◽  
Vol 40 (3) ◽  
Keyword(s):  
Vertical Flow ◽  
Reed Bed ◽  
And Performance

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.

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.

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.

The design and performance of a vertical flow reed bed for the treatment of high ammonia, low suspended solids organic effluents

1997 ◽  
Vol 35 (5) ◽  
pp. 197-204 ◽  
Author(s):  
Michael Morris ◽  
Robert Herbert
Keyword(s):  
Suspended Solids ◽  
Cod Removal ◽  
Vertical Flow ◽  
Ammoniacal Nitrogen ◽  
Influent Concentration ◽  
Infiltration Rates ◽  
Processing Wastes ◽  
Coarse Substrate ◽  
Reed Bed ◽  
And Performance

A design approach for vertical flow constructed wetlands based on selection of not only bed size, but also substrate characteristics, configuration, plant species/variety and management is piloted in a trial system to treat sugar beet processing wastes. In the beet processing season these wastes are hot, low in suspended solids and relatively high in ammoniacal nitrogen. The pilot system consists of a small, coarse substrate first stage followed by a larger, fine substrate second stage. Results in the beet processing season show 87.3% COD removal, 87.7% TSS removal and a 79.5% reduction in ammoniacal nitrogen. Treating larger volumes of cooler stored wastes out of season, the mean removal efficiencies were 73.9% for COD, 88.0% for TSS and 93.4% for ammoniacal nitrogen. TSS removal m−2 was found to be independent of influent concentration and temperature, whilst COD removal m−2 was found to be independent of temperature, but not influent concentration. Removal of ammoniacal nitrogen appeared to be dependent upon influent concentration and, in particular, upon temperature. Infiltration rates were shown to be negatively correlated to length of dosing cycle. Simple models of substrate permeability based on substrate particle size distribution are seen to be inadequate for describing infiltration rates in vertical downflow systems, even those treating low strength wastes.

The design, operation and performance of a municipal hybrid reed bed treatment system

2003 ◽  
Vol 48 (5) ◽  
pp. 119-126 ◽  
Author(s):  
S. O'Hogain
Keyword(s):  
Treatment System ◽  
Septic Tank ◽  
Vertical Flow ◽  
Max Planck ◽  
Operational Characteristics ◽  
Monitoring Study ◽  
Pump Sump ◽  
Reed Bed ◽  
And Performance ◽  
Final Effluent

The first Irish municipal application of a hybrid reed bed treatment system (RBTS) was designed and constructed at Colecott, County Dublin. The hybrid design for Colecott RBTS was based on modifications to the Max Planck Institute Process (MPIP). The constituent parts of the design were a septic tank, a pump sump, two stage vertical flow beds, a secondary settlement tank, a horizontal reed bed, an outlet chamber and outfall pipe. The population at the time of design was 48, but with future development in mind 60 was used as the population equivalent (pe). Construction and operational characteristics are outlined. Results of a two year monitoring study are presented, showing good performance and producing a final effluent with 88% BOD removal, 89% COD removal and 99% SS removal. Percentile compliance with EU discharge standards were BOD 60%, COD 100%, SS 100% with 50% for nitrogen and 0% for PO4. Surface water input increased flows to twice the average, resulting in increased maintenance visits without affecting results. The ability to deal with the excess inflow is demonstrated by the system. The method of distribution to the primary vertical beds was satisfactory while that on the secondary vertical beds was not.

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.

Compact vertical flow constructed wetland systems - first two years’ performance

2003 ◽  
Vol 48 (5) ◽  
pp. 15-23 ◽  
Author(s):  
C.M. Weedon
Keyword(s):  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Oxygen Demand ◽  
Phosphate Removal ◽  
Normal Operation ◽  
Vertical Flow ◽  
Average Percentage ◽  
Load Rate ◽  
Reed Bed

In order to move towards optimising wastewater treatment performance by vertical down-flow reed beds, user and installer demands were applied to design, resulting in the “compact vertical flow reed bed” (CVF bed). Performance data are presented for the two years since commissioning a CVF bed and pond system serving eight residents. Particular emphasis was placed on investigating oxygen transfer rate and susceptibility to hydraulic overloading. Average percentage concentration reduction effected by single passage through the bed exceeded 97% for suspended solids and biochemical oxygen demand, and 90% for ammoniacal nitrogen and total Kjeldahl nitrogen. The occurrence of nitrification and denitrification (up to 58%) within the same bed was clearly indicated. Percentage ortho-phosphate removal averaged 92% over the first 17 months’ operation and thereafter fell to approximately 45%. Faecal coliform density underwent an almost four log reduction. Oxygen transfer rate within the reed bed was between 28-36 gO2/m2.d. Normal operation was maintained until six times dry weather hydraulic load rate was exceeded, at which point surface flooding occurred. The capacity of a single vertical flow reed bed to achieve effective treatment of domestic sewage was demonstrated, with no requirement for reduced load rates, promising substantial advantages over established approaches.

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