STUDY OF BURNT RICE HUSK PERFORMANCE IN REEDBEDS TO

REMOVE POLLUTANT FROM LANDFILL LEACHATE

NTJRUL ANATI ARIFFIN

A thesis submitted in partial fulfillment of the

requirement for the award of the degree of

Bachelor of Civil Engineering

Faculty of Civil Engineering & Earth Resources

University Malaysia Pahang

NOVEMBER 2010

V

ABSTRACT

In this study, the raw material used to treat the leachate is rice husks.

Analyses were done on their physical and optical parameters to determine the

removal and reduction of heavy metals (iron, chromium and nickel), BOD 5, COD, ammonia nitrogen, turbidity, colour and odour in leachate using biological treatment.

For the physical, the testing was running to examine the performance of reedbed to

improve landfill leachate. While for the optical parameter, scanning electron

microscope (SEM) was used to investigate their morphological structures to

determine the effect of burnt rice husk sizes and porosity on pollutant removal. At

the end of the study, those criteria were exhibited from testing results, the treatment

of leachate in reedbeds effective until four days and this reedbeds can be

commercialized. Besides that, the raw materials used can be abundantly earned

without cost, which in turn reduce the cost of production. Moreover, by this way, it

can reduce the sludge disposal, which make it highly valuable in terms of

environmental, and market value.

vi

ABSTRAK

Dalam kajian mi, bahan mentah yang digunakan untuk rawatan air sampah

adalah sekam padi. Parameter-parameter yang dikaj i adalah dari segi fizikal dan

optikal untuk menentukan penyingkiran dan pengurangan logam berat (ferum,

kromium dan nikel), BOD5, COD, ammonia nitrogen, kekeruhan, warna dan bau

secara rawatan biologikal. Bagi ujian fizikal, pengujian dilakukan untuk menguji

prestasi 'reedbed' bagi memperbaiki tapak pembuangan air sampah. Parameter

optikal pula, mikroskop elektron mikrografikal (SEM) digunakan untuk mengkaji

struktur marfologi bagi menentukan kesan saiz sekam padi (kasar dan halus) yang

dibakar dan kadar penyingkiran pencemaran. Di akhir kajian, kriteria tersebut

dipamerkan daripada keputusan ujian di mana rawatan pembersihan air sampah di

dalam 'reedbed' tersebut berkesan sehingga hari ke empat dan 'reedbed' mi boleh

dikomersilkan. Selain itu, bahan mentah yang digunakan boleh di dapati dengan

mudah dan banyak tanpa melibatkan kos yang tinggi setenusnya mengurangkan kos

pengeluaran. Dengan cara mi, kita dapat mengurangkan pembuangan enapcemar

seterusnya dapat menjaga alam sekitar dan sangat berharga dari segi nilai pasaran.

TABLE OF CONTENTS

CHAPTER

TITLE PAGE

STUDENT DECLARATION

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

1

INTRODUCTION 1

1.1 Background 1

1.2 Problem Statement 2

1.3 Objectives 3

1.4 Scope of Study 4

1.5 Gantt Chart S

2 LITERATURE REVIEW 6

2.1 Reedbeds 6

2.1.1 Type of Reedbeds 7

2.1.2 Hydraulic Loading Rate and Hydraulic 8

Residence Time

2.1.3 Media in Reedbeds 10

2.2 Macrophytes (cattails) in Reedbeds 12

2.3 Rice husk 16

2.3.1 Rice Husk in Reedbeds 18

2.3.2 Characteristic of Rice Husk 19

2.4 Landfill Leachate 20

2.4.1 Source of Leachate Production 21

2.4.2 Characteristic Landfill Leachate 22

2.4.3 Leachate Management 27

2.4.4 Leachate Treatment 27

2.4.4.1 Leachate by Biological Treatment 29

2.4.5 Biological Oxygen Demand (BOD5) 31

2.4.6 Chemical Oxygen Demand (COD) 32

2.4.7 Heavy Metal Removal 32

2.4.8 Nitrogen Removal 35

2.4.9 Phosphorus Removal 36

2.4.10 Pathogens Removal 37

2.4.11 Ammonia Nitrogen Removal 38

2.4.12 Iron Removal 39

2.4.13 Hydrogen Ion Concentration (pH) 39

3 METHODOLOGY 40

3.1 Introduction 40

3.2 Methods 42

3.2.1 Literature Method 42

3.2.2 Experimental Method 42

3.2.2.1 Sample Collection 43

3.2.2.2 Design 43

3.2.2.3 Plan Preparation 46

3.2.3 Data Collection 52

3.3 Procedure of Testing 52

3.3.1 Sieve Analysis of Gravel and Rice Husk 53

3.3.2 Activated Carbon Adsorption 55

3.3.3 Biochemical Oxygen Demand (BOD) 55

3.3.4 Chemical Oxygen Demand (COD) 56

3.3.5 Ammonia Nitrogen 57

3.3.6 Hydrogen Ion Concentration (pH)

57

3.3.7 Turbidity 58

3.3.8 Heavy Metals 58

3.3.8.1 Iron (Fe)

59

3.3.8.2 Chromium (Cr)

59

3.3.8.3 Nickel (Ni)

60

4 RESULTS AND DISCUSSION 61

4.1 Introduction 61

4.2 Scanning Electron Microscope (SEM) Analysis 62

4.3 Activated Carbon Adsorption 63

4.4 Leachate Before Treatment 67

4.5 Leachate After Treatment

68

CONCLUSION

83

5.1 Summary 83

5.2 Recommendation for Future Project 84

5.3 Commercialization Potential

85

REFERENCES

86

APPENDICES

LIST OF TABLES

TABLE NO TITLE PAGE

2.1 Characteristics of typical media, source (Crites 11 and Tchobanoglous, 1998; WEF, 2001)

2.2 The physical properties of untreated RHA 19

2.3 Landfill leachate classification vs. age 23

2.4 ANZECC guideline levels as compared with 24 average levels of pollutants in leachate

2.5 Guideline levels of leachate (Standard Level of 24 Environmental Quality Act 1974)

2.6 Leachate concentration in different phases 25

2.7 Metal concentrations in leachate at different 25 phases

2.8 Elimination mechanism in landfill leachate 26

2.9 Removal efficiency comparison between the 30 reactors

2.10 Effects of heavy metals to human body 34

4.1 Pollutant in landfill leachate at Jerangau landfill, 68 Gebeng before treatment compared with Standard Level of Environmental Quality Act 1974

4.2 Parameter in control reedbed from 1 to 5 days 69

4.3 Parameter in reedbed integrate with granular burnt 69 Rice husks from 1 to 5 days

4.4 Parameter in reedbed integrate with powdered 70 burnt Rice husks from 1 to 5 days

LIST OF FIGURES

FIGURE NO TITLE PAGE

2.1 Basic reedbed design (lateral view) 6

2.2 Method of implementation to planting the plant 13

2.3 Cattails 13

2.4 Super turbo rice husk gasifier stone 16

2.5 Rice husk 17

2.6 The flow of heavy metals 33

3.1 Research methodology 41

3.2(a)(i) Elevation of typical model of subsurface flow reedbeds 48

3 .2(a)(ii) Detail of input pipe 49

3.2(b) Schematic layout (plan) of pilot design of SSF reedbeds 50

3.3(a) Model of reedbeds 50

3.3(b) Reedbeds in control, granular and powdered burnt rice

3.4(a) Cleaning of burnt rice husk 53

3.4(b) Rice husk inserted in the tray 54

3.4(c) Ibrying of burnt rice husk in oven 54

4.1(a) SEM Micrograph of granular activated carbon (GAC) 62 Burnt rice husk magnify at 500 X

4.1(b) SEM Micrograph of granular activated carbon (GAC) 63 Burnt rice husk magnify at 1.50 K X

4.2(a) Adsorption testing of burnt rice husk in Methylene blue 65

4.2(b) Calibration curve of methylene blue adsorption 66

4.2(c) Adsorption capacity of PAC rice husk

4.2(d) Adsorption capacity of GAC rice husk 67

43 Comparison of pH for control, granular and powdered 70

44 Comparison of BOD for control, granular and powdered 71

45 Comparison of COD for control, granular and powdered 72

4.6 Comparison of Turbidity for control, granular and 73

47 Comparison of Ammonia Nitrogen for control, granular 74 Powdered

4.8 Comparison of Iron for control, granular and powdered 75

4.9 Comparison of Chromium for control, granular and 76 powdered

4.10 Comparison of Nickel for control, granular and powdered 77

4.11 Comparison of Colour for control, granular and powdered 78

4.12 Comparison of leachate before treated and after one day 79 treated

4.13 Comparison of leachate before treated and after two days treated

4.14 Comparison of leachate before treated and after three 80 treated

4.15 Comparison of leachate before treated and after four days 81 treated

4.16 Comparison of leachate before treated and after five 81 treated

cuAniiu

BTRODUCTIoN

1.1 Background

In Malaysia, most of landfill is open landfill and produced - high contaminant

which very harmful and danger to human and environment. Therefore, it is necessary

to treat the leachate and design a proper leachate treatment plant, so that It can meets

the standards for discharge into sewer or into natural waterways. Generally, leachate

and runoff from the landfill site are stored in ponds at the foot of the mound. During

dry periods the leachate is irrigated onto the top of the completed waste mound

where it evaporates or transpires into the atmosphere. Meanwhile, during heavy

rainfall the leachate is overflows into a system of landfill and contaminated a

waterways especially groundwater.

Nowadays, biotechnology is a popular investment and contributes high

incomes for Malaysia economic. It would be useful to evaluate the nutritive value of

rice husk ash in an effort to create an attractive alternative for the rice processing

industry, which could provide a new income source for a rice mill as well as eliminating or greatly reducing, space for agricultural wastes. As an agro waste

material rice husk is a fibrous material with high silica content. The application rice

husk is not only revitalizes our plants but, it induces uniformity in growth by enhancing water retention and microbial activity. Risk husk contains high quality of

nutrients that keep the soil healthy in a natural way. It acts as a top dressing that

helps maintain moisture and reconditions the soil. Rice husk enhances the nutrient

carrying capacity of plants.

Reedbeds is essentially a channel, lined with an impermeable membrane,

filled with sand/gravel, and planted with reeds used for treatment of leachate and can

be functional as wetland. Leachate that has black or grey colour is passed through

the root zone of the reeds where it undergoes treatment. In this study, the cattail is

used for absorption of nutrients, particularly nitrogen and phosphorus in wastewater.

While, a burnt rice husks was assimilate with sand to absorb the pollutant in leachate

and to study the performance of pollutant removal. Reedbed have three types of

design, where commonly used are surface flow (SF) reedbed, sub surface flow (S SF)

reedbeds, and vertical flow (VF) reedbeds. However in this study sub surface flow

(S SF) is used to investigate the performance of precursor integrated reedbed with

burnt rice husk.

1.2 Problem Statement

By products of rice husk is a large problem and sold at low costs. Hence, this

by product should be used for an increased value application and expand the

knowledge of biotechnology to improve human life. Rice husk is a waste from the

industry, which is, founded easily in north Malaysia especially Kedah and Penis.

Rice husk can be functional as a good adsorbent especially as a filter to treat the

leachate. It not only reduces the cost of leachate management but also adds values to

waste.

The methods currently employed for the removal of heavy metal from

leachate are cation-exchange and precipitation. However, these methods have several disadvantages that include high cost and toxic sludge. Lately, several Malaysian

newspapers have reported the problem faced by local government regarding

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contamination cause by obstruction of landfill lèachate into river and groundwater,

which affect the quality of water resources. Therefore, it is necessary to treat

leachate before it was discharge into waterways especially river and groundwater.

The precise mechanism by which bacterial/pathogenic microorganism removal

occurs in SSF systems are not well understood although it is attributed to a

combination of physical, chemical and biological. These comprise natural decay,

predation, sedimentation, adsorption, filtration, and the excretion of anti-microbial

compounds from the roots of plants.

1.3 Objectives

The purpose of this study is to identify the properties and characteristics of

burnt rice husk to be used in reedbeds and it potential as a filter media. There are

three (3) objectives to be achieved:

i. To determine the effect of burnt rice husk sizes and porosity on pollutant

removal.

ii. To examine the performance of integrated reedbeds assimilate with burnt rice

husks to improve landfill leachate.

iii. To determine the removal and reduction of heavy metal (Fe, Cr and Ni),

BOD5, COD, ammonia nitrogen, turbidity, colour and odour in leachate in

integrated reedbed.

1.4 Scope of Study

The rice husk was collected in Bukit Besar, Alor Setar, Kedah.While, the

cattails (MacroPhYtes) is taken at Gebeng and the sample of landfill leachate were

collected from Jerangau landfill and brought to the Environmental Laboratory in

FKASA of Universiti Malaysia Pahang for testing. These tests are done for one

month to get accurate result in experimental.

The rice husk was burnt and sieved according to two size sieve (600.t to 63[t

mm for powdered and 3.35 mm to 2 mm for granular) and placed into three pilot

tanks of reedbeds, to determine the effect of burnt rice husk and pollutant removal.

In this study, there are three pilot tanks of subsurface flow reedbeds were

design to examine its performance of reedbeds to improve landfill leachate. The

three pilot tanks were design according to ratio 4 (long): 3 (wide): 2.5 (depth) to

avoid hydraulic problem. There is some parameter and calculation for design

reedbed are neglected such rain precipitation due to limited focuses of study. The

expected results were obtained through comparison graph are followings:

i. BOD5 versus Time (day)

ii. COD versus Time (day)

iii. Ammonia Nitrogen versus Time (day)

iv. Turbidity versus Time (day)

V. pH versus Time (day)

vi. Metals versus Time (day)

vii. Colour versus Time (day)

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CIIAITER 2

LITERATURE RE VIE V.'

2.1 Reedbeds

A reedbed is essentially a channel, lined with an impermeable membrane that

is filled with gravel and planted with macrophytes i.e. reeds, rushes (Figure 2.1) and

used to treat wastewater. Wastewater, black or grey, is passed through the root zone

of the reeds where it undergoes treatment. Inlet and outlet pipes are positioned below

the gravel surface, so that the water always remains below the gravel surface, thus

excluding human exposure to the wastewater, mosquito breeding and unpleasant

odours.

IJ4.

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........ . .... .. . . ..

Figure 2.1: Basic Reedbed Design (Lateral View)

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ReedbedS are generally designed to detain the wastewater for a period of 5

to 7 days. This residence time aids with the treatment by allowing sufficient time for

the settling and filtering of suspended solids, nitrification/denitrification to occur,

fixation onto the substrate, breakdown of organic matter and nutrient removal via

micro-organisms and plant uptake. Residence time is generally governed by the

surface area and depth of the reed bed. The die-off of pathogens in a reed bed is due

to predation by micro-organisms on the surface of the gravel and roots, unfávourablé

conditions provided by a long residence time, and the aerobic and anaerobic zones in

the reed bed. Therefore, the quality of treated effluent improves with Increased

residence time. Effect/advantages of reedbeds as following:

i. The bio-dègradation of effluents through a vertkal flow, aerobic natural

filter system can produce clean clear water and no smell.

ii. Reedbeds are a low cost alternative, designed for low maintenance and

lasts for many years.

iii.Reedbeds work well on installation, and Improve to optimum

effectiveness within three months.

iv. Reedbeds have been successfully tested with bomestic, Agricultural and

Industrial effluents.

v. While a eedbed Filtration system does need a certain area of land, the

size can be remarkably small.

A. Reedbed Filtration can bring about much needed and cost effective

solutions to the major contamination of freshwater systems.

2. 1.1 Types of Reedbeds

According to Van Oirschot et. Al (2002), there is three types of reedbeds can

be used in commercial systems which are Surface flow (SF) reedbed, Sub surface

flow (S SF) reedbeds, and Vertical flow (V reedbeds.

However in this study, SSF reedbeds were design to conduct the pilot test.

Subsurface flow (SSF) reedbeds are constructed wetlands for the biological treatment

of wastewater with the principal advantages of avoidance of odour, mosquitoes and

public contact as the wastewater level is maintained below the media surface. It is

also more efficient and hence requires less land than SF, SSF and VF wetlands

(Kadlec and Knight, 1996). Pathogen removal, as indicated by fecal coliform levels,

in SSF wetlands is generally recognized as being superior to that of SF wetlands.

Research by Green et al. (1997) has confirmed the ability of SSF reedbeds to achieve

2 log removals of E. coli and coliform at retention times of 24 h or more.

Based on previous studies, treatment wetlands (reedbeds) have been used

successfully in tropical Asia (Koottatep and Poiprasert, 1997) and Africa (Kaseva,

2004) however little information exists on their use in the tropics of Latin America.

Experience with reedbeds for the successful treatment of grey water exists in

Australia (Ho et al., 2001), United States (Del Porto and teinfèld, 1999) and Europe

(Otterpohi, 2001). Reedbeds have been used in Mexico for domestic grey water

treatment using papyrus, typha and scirpus (CITA, 2002) although no performance

data are available and reedbeds (biofihtros) have been used successfully in Nicaragua

for the treatment of primary treated domestic sewage Platzer et al., 2002).

2.1.2 Hydraulic Loading late and Hydraulic Residence Time

The amount of wastewater entering a reedbed over a given period - of time is

described by the hydraulic loading rate (HLR) which is calculate as follows:

HLR (q) = Q/A

Where: Q Flow rate (m3/day)

A = Reedbed area (m)

The average length of time wastewater spends in a reedbeds governs the

degree of treatment it receives and is known as the hydraulic residence time (HRT)

usually given in days. It can be calculated theoretically as follows:

HRT = LWDn/Q

Where: L = Length of -wetiand'(m)

W= Width of wetland (m)

Depth of water in wetland (m)

n = Porosity of wetland media

Q Flow rate (m3/day)

The equation does not take into account any other factor such as seepage,

precipitation (p), evaporation (E) and evapotranspiration (ET). An overall water

budget can however be determined If these elements are known and assumptions

made (e.g. seepage is negligible) as follows:

Water balance: Q0 = Q1 + (P - ET) A

Where: Q' = Inflow rate (m3/day)

Q° = Outflow rate

P = Precipitation rate (mid)

ET = Evapotranspiration rate (mid)

A = Wetland top surface area (m)

The effect of rainfall is to reduce the retention time, raise water levels and

dilute concentrations whereas evapotranspiration has the opposite effect. Kadlec and

Knight (1996) indicate that for design purposes the h!torica[ monthly average

precipitation is sufficient, and that as specific ET rates are difficult to accurately

measure, it is common practise to assume that wetland ET rates are some percentage

of open water or pan evaporation rates. ET rates will vary depending upon plant type

and density but rates 1.5 to t times the pan evaporation has been reported fOr SSF

wetlands (USEPA, 1999). ET losses of 5 mm/day have been reported in summer in

southern USA which may be more than half the daily inflow as many wetlands are

typically only receiving 10 mm/day hydraulic load (Kadlec and Knight, 1996).

Conducting a mass balance is the most accurate way to characterise water

quality functions in a wetland as it. allows closure for the chemical of interest to be

achieve, but as the outflow volume is often not monitored this is rarely achieved

(Kadlec and Knight, 1996).

2.1.3 Media in Reedbeds

The substrate in reedbeds is defined to include the bed media (usually gravel),

roots and plant rhizomes (WEF, 2001). The purpose of the media is:

i. To provide a substrate with high hydraulic conductivity around

which the wastewater can flow.

ii. To provide a surface area for biofilm growth (periphytic attached-

growth microorganisms).

iii. To assist in the removal of fine particles by sedimentation and

filtration.

iv. To provide support for the roots of emergent plants.

(DLWC, 1998)

Typically, the media for reedbeds consists of sand, gravel or crushed rock.

This is generally excavated locally to minimise haulage cost and represents the

exploitation of a non-renewable resources. In the US the cost of imported gravel was

found to be between 40 to 50% of the total construction cost. This range was

dependent upon the distance the gravel s hauled and whether an artificial liner was

also required (USEPA, 2000). From and economics viewpoint, this high cost of the media represents the single largest disadvantage SSF wetlands have over FWS

systems (Crites and Tchobanoglous, 1998; WEF, 2001). An alternative low-cost

media for S SF wetlands has the potential to greatly increase the uptake of this

technology, particularly in developing countries.

The gravel used in SSF system typically varies in size from 3 mm to 38 mm.

The requirements of a gravel-based substrate are that it be clean, hard, durable and

capable of retaining its shape and maintaining permeability of the wetland over the

long term (USEPA, 2000). It should also presumably be inert. The flow of

wastewater through a reedbed will be determined by the hydraulic gradient,

hydraulic conductivity, size and porosity of the media. Typical media characteristics

are given in Table 2.1.

Table 2.1: Characteristics of typical media, Source: (Crites and Tchobanoglous, 1998; WEE, 2001).

Media type Effective size d 10, Porosity, n Hydraulic

(mm) Conductivity, K

(m3/m2/day)

Medium sand 1 0.30 5,000

Coarse sand 2 032 1,000

Gravelly sand 8 0.35 5,000

Medium 32 .40 10,000

gravel 128 0.45 100,000

Coarse gravel

2.2 MacrOPhYtes (Cattails) in Reedbejjs

Paul D. N. Hebert (2007) has been reported that, Macrophytes are the

conspicuous plants that dominate wetlands, shallow lakes, and streams. Macroscopic

flora includes the aquatic angiosperms (flowering plants), pteridophytes (ferns), and

bryophytes (mosses, hornworts, and liverworts). An aquatic plant can be defined as

one that is normally found growing in association with standing water whose level is

at or above the surface of the soil. Standing water includes ponds, shallow lakes,

marshes, ditches, reservoirs, swamps, bogs, canals, and sewage lagoons. Aquatic

plants, though less frequently, also occur in flowing water, in streams, rivers, and

springs.

Macrophytes constitute a diverse assemblage of taxonomic groups and are

often separated into four categories based on their habit of growth: floating

unattached, floating attached, submersed, and emergent. Floating unattached plants

are those in which most of the plant is at or near the surface of the water. Roots, if

present, hang free in the water and are not anchored to the bottom. Floating attached

plants have leaves which float on the surface, but their stems are beneath the surface,

and their roots anchor the plant in the substrate. Submersed plants are found when

the entire plant is below the surface of the water. Emergent plants are those whose

roots grow underwater, but their stems and leaves are found above the water. Figure

2.2 has shown the method to planting the plant on the sewage plant.

Nutrients, Sediment, Metal, Toxic

p. . •H Nitrogen Gas

• ..A

t! t H Th Sedimentation

Phosphorus Absorption to Organic Materials - •.. .-••-

- A Sedimentation & Precipitation

Ca

Uptake by Plants &

Microbe

Uptake Release by Microbe • - • --

Wetland • .

Figure 2.2: Method of implementation to planting the plant

Cattails are ubiquitous in distribution, hardy, capable of thriving under

diverse environmental conditions, and easy to propagate and thus represent an ideal

plant species for constructed wetlands. They are also capable of producing a large

annual biomass and provide a small potential for N and P removal, when harvesting

is practiced. Cattail rhizomes planted at approximately I in (3.3-ft) intervals can

produce a dense stand within three months (Miller, I.W.G., and S. Black.).

•

'.\ \'. \ - •• ' . L -

t

I- -'

: :

- V

Figure 2.3: Cattails

In late summer and fall, they form the brown seed heads that so many of us

associate with cattails. A small area of cattails can be visually pleasing as well as

provide fish and wildlife habitat. However, cattails rapidly spread via seeds and

roots. In just a few short years without management, cattails takeover a ponds

shallow water areas. It is not unusual to see ponds that are completely surrounded by

cattails. This ruins the ponds visual and recreational benefits. Fortunately, cattails

can be successfully managed. This is largely up to the owner to decide, based on his

or her management goals.

Many pond owners prefer not to have any cattails because of their explosive

ability to spread and the subsequent effort required to manage them. Other owners

like areas of cattails because of

the natural, pleasing aspect of them and for their

value as fish and wildlife habitat. Most often, these owners like to limit cattails to

about 10% of the shoreline areas. In a round one-acre pond, this would result 1n

about 75 feet of shoreline. If you are an owner desiring some cattails, it is important

for you to physically mark the areas you desire cattails and then prevent their spread

outside the area. This requires occasional vigilance by the owner.

Two chemical compounds are the most effective in controlling cattails and

are approved for aquatic use. These are diquat and glyphosate. Common trade names

for these products are Reward (diquat) and Rodeo (glyphosate). However, a number

of companies market other aquatic products using these compounds. They are

generally available or can be ordered through agricultural supply or feed stores.

Using either compound in accordance with the product label should not result in

adverse effects on fish.

Diquat is a contact herbicide, meaning it kills only those portions of the

plant that it touches. Thus, complete coverage of the cattail is needed to eliminate the

plant. This requires spraying the area of cattails from several directions, a definite

drawback Another drawback is that diquat does not travel through the plant and therefore does not reach the cattails roots. The root system is not killed, allowing the

same roots to grow new shoots the following year. Using diquat will require yearly applications

Glyphosate is a systemic herbicide, meaning that it travels throughout the

plant killing both the roots and vegetative P01toflS. Systemic herbicides are preferred

in the elimination of perennial plants, which the cattail is classified as. In treating

cattails, a person can walk the shore making sure to spray glyphosate liberally on the

portions of the cattails that can be reached. There is no need to spray from multiple

directions. Another advantage is that one application can totally (or nearly so)

eliminate the cattail stand. One drawback of glyphosate is that it is more expensive

systemic herbicides usually are.

It is recommended with both compounds that a non-ionic surfactant be

added to the solution prior to spraying. Surfactants result in uniform sheeting of the

herbicide over the vegetative surface which increases the uptake of the herbicide.

Cattails have a thick waxy coating on the leaf which slows down herbicide uptake.

Without the surfactant, much of the herbicide would be lost to the liquid beads that

would form and roll off the plant. One ounce of surfactant is generally recommended

for each gallon of spray solution for controlling cattails.

Application timing is critical for cattail control and differs between diquat

and glyphosate products. The contact herbicide diquat can be applied any time the

cattails are green and actively growing. Most owners using diquat products apply in

the summer. Glyphosate products have a narrower window for optimum results.

These products should be applied just after the seed head has formed. Energy

reserves are at their lowest in the roots and the plant begins to store food in the roots

in anticipation of next year's growth. This food is produced in the leaves and

transported to the roots. The application of glyphosate at this time results in its

transport to the roots as well, thereby killing the root system.