Effect of effluent recirculation on the performance of a reed bed system treating agricultural wastewater

2003 ◽  
Vol 39 (3) ◽  
pp. 351-357 ◽  
Author(s):  
G. Sun ◽  
K.R. Gray ◽  
A.J. Biddlestone ◽  
S.J. Allen ◽  
D.J. Cooper
Keyword(s):  
Agricultural Wastewater ◽  
Effluent Recirculation ◽  
Reed Bed

scholarly journals Optimising the performance of a lab-scale tidal flow reed bed system treating agricultural wastewater

2004 ◽  
Vol 50 (8) ◽  
pp. 65-72 ◽  
Author(s):  
Y.Q. Zhao ◽  
G. Sun ◽  
C. Lafferty ◽  
S.J. Allen
Keyword(s):  
Tidal Flow ◽  
High Strength ◽  
Pollutant Removal ◽  
Inorganic Pollutants ◽  
Operational Conditions ◽  
Agricultural Wastewater ◽  
Major Route ◽  
Reed Bed ◽  
Ammoniacal Nitrogen Removal

A gravel-based tidal flow reed bed system was operated with three different strategies in order to investigate its optimal performance for the treatment of a high strength agricultural wastewater. According to the three strategies, individual reed beds were saturated and unsaturated with the wastewater for different periods while reasonably stable hydraulic and organic loadings were maintained. Experimental results demonstrated that the system produced the highest pollutant removal efficiencies with a relatively short saturated period and long unsaturated period, highlighting the importance of oxygen transfer into reed bed matrices during the treatment. Significant removals of some major organic and inorganic pollutants were achieved under all three operational conditions. Nitrification was not the major route of ammoniacal-nitrogen removal when the system was under high organic loading. Due to the filtration of suspended solids and the accumulation of biomass, gradual clogging of the reed bed matrices took place, which caused concerns over the long-term efficiency of the tidal flow system.

Treatment of domestic and agricultural wastewater by reed bed systems

1999 ◽  
Vol 12 (1-2) ◽  
pp. 13-25 ◽  
Author(s):  
Jürgen Kern ◽  
Christine Idler
Keyword(s):  
Agricultural Wastewater ◽  
Reed Bed

Treatment of Agricultural Wastewater in a Combined Tidal Flow-downflow Reed Bed System

1999 ◽  
Vol 40 (3) ◽  
pp. 139-146 ◽  
Author(s):  
G. Sun ◽  
K. R. Gray ◽  
A. J. Biddlestone ◽  
D. J. Cooper
Keyword(s):  
Water Movement ◽  
Tidal Flow ◽  
Treated Wastewater ◽  
Mean Flow ◽  
Combined System ◽  
Agricultural Wastewater ◽  
The Matrix ◽  
Water Recirculation ◽  
Reed Bed ◽  
Suitable Technique

In this study, the efficacy of a full-scale combined tidal flow-downflow reed bed system was tested for the treatment of agricultural wastewater with average BOD5 of 1100 mg/l and NH4-N of 329.5 mg/l. At a mean flow rate of 2.0 m3/d, the BOD5 and COD of the influent were reduced across the system by 97.6% and 71.3%, respectively. Considerable SS and PO4-P removals were also achieved. NH4-N was reduced by 93.1%. Nitrification proved to be the major process for NH4-N reduction. Although a further polishing treatment is needed, the average BOD5 and NH4-N levels of the treated wastewater were close to those frequently required in UK discharge consents. The highest BOD5, COD and NH4-N removals and oxygen consumption rate were achieved in the tidal flow stage of the combined system; this suggests that the rhythmical air/water movement in the matrix of the tidal flow beds can benefit the treatment by providing higher oxygen flux and more efficient utilisation of the available bed volume. Better results for BOD5, COD and NH4-N removals were obtained in downflow beds with water recirculation than in those without this recycle. Therefore the recirculation of effluent around each treatment stage is a suitable technique for improving the performance of downflow reed beds.

Treatment of Agricultural Wastewater in a Pilot-Scale Tidal Flow Reed Bed System

1999 ◽  
Vol 20 (2) ◽  
pp. 233-237 ◽  
Author(s):  
G. Sun ◽  
K. R. Gray ◽  
A. J. Biddlestone
Keyword(s):  
Tidal Flow ◽  
Pilot Scale ◽  
Agricultural Wastewater ◽  
Reed Bed

Constructed reed beds: appropriate technology for small communities

1995 ◽  
Vol 32 (3) ◽  
pp. 339-348 ◽  
Author(s):  
M. B. Green ◽  
J. Upton
Keyword(s):  
Sewage Treatment ◽  
Appropriate Technology ◽  
Great Promise ◽  
High Quality ◽  
Reed Beds ◽  
Small Communities ◽  
Operational Information ◽  
Reed Bed ◽  
Small Sites ◽  
Very High

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.

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.

Enhancement of nitrogen removal in subsurface flow constructed wetlands employing a 2-stage configuration, an unsaturated zone, and recirculation

1995 ◽  
Vol 32 (3) ◽  
pp. 59-67 ◽  
Author(s):  
Kevin D. White
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Subsurface Flow ◽  
Great Promise ◽  
Effluent Recirculation ◽  
Wetland Treatment ◽  
Subsurface Flow Constructed Wetlands ◽  
Inlet Zone ◽  
Bod Removal

Constructed wetland technology is currently evolving into an acceptable, economically competitive alternative for many wastewater treatment applications. Although showing great promise for removing carbonaceous materials from wastewater, wetland systems have not been as successful at nitrification. This is primarily due to oxygen limitations. Nitrification does occur in conventional wetland treatment systems, but typically requires long hydraulic retention times. This paper describes a study that first evaluated the capability of subsurface flow constructed wetlands to treat a high strength seafood processor wastewater and then evaluated passive aeration configurations and effluent recirculation with respect to nitrogen treatment efficiency. The first stage of a 2-stage wetland treatment system exhibited a relatively short hydraulic retention time and was designed for BOD removal only. The second stage wetland employed an unsaturated inlet zone and effluent recirculation to enhance nitrification. Results indicate that organic loading, and thus BOD removal, in the first stage wetland is key to optimal nitrification. Passive aeration through an unsaturated inlet zone and recirculation achieved up to 65-70 per cent ammonia nitrogen removal at hydraulic retention times of about 3.5 days. Inlet zone configuration and effluent recirculation is shown to enhance the nitrogen removal capability of constructed wetland treatment systems.

Sign in / Sign up

Export Citation Format

Share Document