Reed Bed Technology

SATPAL

ENVIRONMENTAL ENGINEERING

Civil Engineering Department S V NATIONAL INSTITUTE OF TECHNOLOGY, SURAT

Topics

Introduction

Working of reed beds

Types of reed beds

Factor Influencing the purification process of reed beds

Features of reed bed system

Application

Benefits

Conclusion

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INTRODUCTION Reed beds are gravel filled, contained, shallow beds, planted

with plants (e.g. reeds), and specially design to treat

wastewater including sewage, agricultural, industrial and road

wastewaters.

Wastewater, black or grey, is passed through the root zone of

the reeds where it undergoes treatment.

Primary treated effluent from the house is initially filtered

prior to entering the reed bed through an effluent filter fitted to

the grey-water collection tank or septic tank outlet pipe then it

is passes through reed bed system.

Reed beds are generally designed to detain the wastewater for

a period of 5 to 7 days and the quality of treated effluent

improves with increased residence time (1).

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WORKING OF REED BEDS

Fig.1. http://www.permaculturenews.org/images/how-reed-bed.jpg 4/25

The Phragmite is one of the most widespread flowering plants in

the world. It is a tough adaptable plant, which can grow in polluted

waters and find sustenance in sludge.

Reed beds perform three basic functions(3):

(1) Dewater the sludge: - Dewatering is accomplished

through evaporation (as in a normal sludge drying bed operation).

(2)Transform it into mineral and humus like components:

- transpiration through the plants roots stem, and leaf structure.

(3) Store sludge for a number of years: - filtration through

the bed's sand and gravel layers and the plant's root system

Continue………….

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Fig.2. http://www.nireedbeds.co.uk/images/general/diagram2.gif 6/25

TYPES OF REED BEDS

Horizontal Flow Reed Beds

The effluent enters at one end and travels horizontally through the

reeds root zone, before being discharged on the far side of the bed.

These reed beds works particularly well for low strength effluents, or

effluent that have been pre-treated.

They are also of no real use for reducing ammonia levels, but they

can reduce the level of BOD (Biochemical Oxygen Demand) and SS

(Suspended Solids) in sewage treatment plant effluent. They are

particularly useful in converting nitrates into nitrogen.

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Fig.3 - www.ecotechnologies-international.com 8/25

Vertical Flow Reed Beds

The reed beds are lined with deeper structures made up of

layers of various sized gravels planted with reeds. In this

system effluent is delivered to the top of the bed in

batches, floods the surface of the bed and drains through.

Each batch traps oxygen in the bed leading to an aerated

system.

Vertical flow systems are more efficient than horizontal

flow reed-beds and can handle stronger strength effluent.

They can reduce ammonia as well as BOD and SS levels.

TYPES OF REED BEDS

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Fig.4. http://www.ecodesigns.co.uk/resources/vf%20reed%20bed%20section.jpg 10/25

FACTORS INFLUENCING THE PURIFICATION

PROCESS OF REED BEDS Life of Reed beds

Reed beds are not a long term solution. They are a relatively new idea and even when they are designed and maintained properly, they will only be viable for up to a maximum of 7 to 10 years for reed beds that follow a full treatment plant as a final polishing filter only (3).

Power Requirement and System Costs

Unless the site has a decent gradient, it is not usually possible to avoid the need for electrical power when designing a reed bed system. Reed bed systems for treatment of wastewater is very low cost treatment method only a very low initial and maintenance cost is required for construction and operation of reed beds.

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Maintenance and Replacement of the system

Reed bed systems are not low maintenance and a regular

maintenance programme is required to keep them

working properly.

The owner will also require several injections every year

against leptospirosis, Hepatitis, etc. so fear of needles is

also a nuisance

Continue………….

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The Role of Plants

The specially selected plant species (Phragmite species

e.g. Phragmite karka and Typha angustus) is used.

The roots of the aquatic plant introduce atmospheric

oxygen down into the body of soil, facilitating the diversity

of microorganisms to flourish around the plant roots. It is

essential for the effective breakdown of various organic

and inorganic compounds.

The plants are capable of taking up a certain amount of

nutrients from the wastewater itself.

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Fig.5. sources:http://tcpermaculture.com/site/wp-content/uploads/2013/05/Reeds03.jpg

Phragmite karka

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Factors influencing the purification process of reed bed

treatment systems

The main factors that typify the treatment characteristics are:

Hydraulic loading rate (m³/[ha x d]) and hydraulic detention

time(d)

Temperature

Influent pollutant concentration

Oxygen supply

Development stage of the reed ecosystem (this sequence is in

random order, not according to quantitative importance)

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The basic features of reed bed technology are given below:-

Operation and maintenance free

Can handle difficult effluents

Self-sustaining

Adaptability

Clean and

Cost efficient

FEATURES OF THE REED BED SYSTEM

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The reed bed system is effective in treating effluent from

Rural areas

Food processing industry

Breweries

Animal husbandry

Sewage from residential, institutional and industrial

complexes.

Chemical industry

Applications

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It offers a low cost, low maintenance and sustainable solution to

effluent problems.

A single reed bed system is able to treat effluents from a number

of sources.

The operational cost of this mode is also less, as no trained staffs

is required for its operation.

The treated effluent can be safely used for irrigation and

the crops grown have higher yield and do not create any

health problem.

Benefits

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CASE STUDY

Case study from Ujjain city named “Performance

Evaluation of Reed Grass (Phragmites karka) in Constructed Reed

Bed System (CRBs) on Domestic sludge, Ujjain city, India (3)”.

Material and Methods

A field scale unit of Reed bed system was established at IEMPS,

Vikram University in the southern area of Ujjain in the state of

Madhya Pradesh, India.

The average temperature varies between 7ºC to 38ºC.

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Continue…………. Physico-chemical Characteristic of reed bed complex after treatment in domestic sludge of Mahanandra Nagar

Parameter Initial 15Days %TP 30days %TP 45Days %TP 60Days %TP

pH 7.90 7.70 2.53 7.50 5.6 7.40 6.33 7.20 8.86

Conductivity(mMho) 1.25 1.20 4.00 1.00 20.00 0.80 36.00 0.55 56.00

Salinity 12.50 12.00 4.00 10.00 20.00 8.00 36.00 5.50 56.00

%Organic Carbon 38.00 37.00 2.63 33.00 13.16 30.00 21.05 28.00 26.32

%Organic Content 65.51 63.79 2.63 56.89 13.16 51.72 21.05 48.27 26.32

%Moisture content 70 58.00 17.14 35.00 50.00 22.00 68.57 11.00 84.29

Bulk density (%) 1.75 1.71 2.29 1.62 7.43 1.53 12.57 1.41 19.43

Total nitrogen (TKN) 37.10 35.70 3.77 25.90 30.19 20.60 44.47 12.17 67.20

Nitrate nitrogen 2.96 2.85 22.58 2.16 49.47 1.95 64.31 1.72 69.13

Ammonium Nitrogen 41.00 39.20 4.39 28.60 30.24 19.80 51.71 11.20 72.68

Organic nitrogen 22.40 20.60 8.04 15.40 31.25 9.62 57.05 5.14 77.05

Available Phosphorus 6.40 5.90 7.81 4.10 35.94 3.50 45.31 2.70 57.81

Total Phosphorus 7.70 7.50 2.60 5.60 27.27 3.10 59.74 1.20 84.84

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Continue…………. Physico-chemical Characteristic of reed bed complex after treatment in domestic sludge of Ravindera Nagar

Parameter Initial 15Days %TP 30days %TP 45Days %TP 60Days %TP

pH 8.10 7.90 2.47 7.70 4.94 7.60 6.17 7.40 8.64

Conductivity(mMho) 1.30 1.20 7.69 1.00 23.08 0.75 42.31 0.60 53.85

Salinity 13.00 12.00 7.69 10.00 23.08 7.50 42.31 6.00 53.85

%Organic Carbon 42.50 41.40 2.59 38.50 9.41 30.10 29.18 23.70 44.24

%Organic Matter 73.27 71.37 2.59 66.37 9.41 51.89 29.18 40.86 44.24

%Moisture content 80.00 71.00 11.25 58.00 27.50 35.00 56.25 14.00 82.50

Bulk density (%) 1.95 1.90 2.56 1.65 15.38 1.32 32.31 0.90 53.85

Total nitrogen (TKN) 40.60 39.90 1.72 33.10 18.47 21.00 48.28 15.00 63.05

Nitrate nitrogen 3.50 3.30 27.59 2.29 44.44 2.20 51.39 1.90 60.53

Ammonium Nitrogen 42.70 41.30 3.28 34.80 18.50 24.90 41.69 13.20 69.09

Organic nitrogen 24.60 22.90 6.91 15.80 37.77 10.10 58.94 4.60 81.30

Available Phosphorus 6.80 6.60 2.94 5.10 25.00 4.30 39.76 2.70 60.29

Total Phosphorus 7.50 7.20 4.00 5.10 32.00 2.50 66.67 1.00 86.67

CONCLUSIONS

The aim of this study was to know about the working of

Reed bed treatment system and their performance and there

type. From the above study we conclude that reed bed

treatment system is a environmental friendly cost effective

and efficient method for the treatment of the waste water

which is coming through the various industries, domestic

sectors, institutional activities.

After the treatment of water if water is reused then a

tertiary treatment is required for reducing their

contamination.

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Reed bed treatment systems have been successfully used

for treating a wide range of wastewater concentrations,

They can also handle a wide range of effluent throughputs

ranging from small and intermittent flows of about 1 m3/d to

several 10,000 m3/d.

The main benefits of the reed bed treatment system is it offers a

low cost, low maintenance and sustainable solution to effluent

problems.

Continue………….

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References http://www.alvinmorrow.com/

Lismore city council, May 2005, The Use of Reed Beds for the Treatment of Sewage & Wastewater from Domestic Households.

Smeal C, P. Truong, J. Biala and A. Butler, Gelita APA, Beaudesert 4285, Australia, ”APPLICATION OF VETIVER GRASS IN SOIL BASED REED BEDS FOR EFFLUENT TREATMENT AT GELITA APA, AUSTRALIA”.

Fact sheet, June 2006, “Reed Beds- A brief guide”

Sushil Manderia, January 2012, Performance Evaluation of Reed Grass (Phragmites karka) in Constructed Reed Bed System (CRBs) on Domestic sludge, Ujjain city, India,

Mohammed Al-Saad, The 1stRegional Conference of Eng. Sci. NUCEJ Spatial ISSUE vol.11, No.3, 2008 pp 494-505”Municipal Wastewater Treatment Using Reed Bed Eco Technology”

Ecotechnologies International, Reed Bed Technology. (www.ecotechnologies-international.com).

http://www.wte-ltd.co.uk/reed_bed_sewage_treatment.html

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