1. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING
17 – 19, July 2014, Mysore, Karnataka, India
AND TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 5, Issue 9, September (2014), pp. 43-48
© IAEME: www.iaeme.com/Ijciet.asp
Journal Impact Factor (2014): 7.9290 (Calculated by GISI)
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ALGAE CONTROL USING RICE STRAW
IJCIET
©IAEME
RUBEENA1, SAVITHA ULAVI2, Dr B. MANOJ KUMAR3
1(M.Tech Scholar, Department of Environmental Engineering,
Sri Jayachamarajendra College of Engineering, Mysore – 570 006, Karnataka, India)
2(Assistant Professor, Department of Environmental Engineering,
Sri Jayachamarajendra College of Engineering, Mysore– 570 006, Karnataka, India)
3(Professor, Department of Environmental Engineering,
Sri Jayachamarajendra College of Engineering, Mysore, Karnataka, India)
ABSTRACT
In recent years, algae is often problem in water supplies as they produce undesirable taste and
odor. Control of its growth is major issue wherever there is sufficient light, moisture and simple
nutrients to sustain them. The present research focus on control of micro-algae by biological means
using rice straw as growth inhibitor. The study was carried out at pilot scale with straw dosage of
25g/m2 and the results obtained were encouraging. Microscopic cell count taken for every five days
after the straw activation, clearly indicated the drop in microalgae and control is attributed to the
synergistic effects of various humic substances and H2O2 released as result of straw decomposition.
Keywords: Algal Blooms, Lignin, Rice Straw, Water Resource
1. INTRODUCTION
Algal blooms create problems in potable supply reservoirs by reducing water quality and
affecting the efficiency of filtration and cleaning processes. Increasing population growth and
industrialization over the past decades has led to an increasing load of pollutants into our water
bodies. Major pollutants include suspended material which causes sediment accumulation at the lake
bottom, organic material which leads to depletion of dissolved oxygen because of microbial
degradation and nutrients[2] (nitrogen-N and phosphorus-P) which lead to eutrophication (excessive
growth of algae).
Algae cause a number of problems. They impede flow in drainage systems, block pumps and
sluices, and interfere with navigation, fishing and other forms of recreation activities [2].Filamentous
algae clogs pumps, screens and emitters in agricultural irrigation systems [1]. Excess of algae in

2. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
water leads to the algal blooms with causes the problems of taste and odour in freshwater bodies.
Algal problems are highly increased because nutrient concentrations in water are rising as a result of
human activity and natural processes.And it has become the global problems which has spread
worldwide from last few decades.The need to control algae, therefore, is increasing for
environmental, recreational and public health purposes. Algal problems can be controlled by various
mechanical, chemical and biological methods.Barley straw (Hordeum vulgare) has been identified as
an effective method for reducing algal growth in a variety of aquatic systems within the United
Kingdom. The use of barley straw to control algae is a cost effective, user-friendly and
environmentally sound. Various researchers have concluded that the barley straw releases some anti-algal
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substances upon decomposition which helps in controlling the algal growth. So, in the present
paper the method of controlling algae by using rice straw has been investigated to check the effect of
straw on the microscopic algae (diatoms) which was abundant in a pond.
2. MATERIALS AND METHODOLOGY
The study was carried out at pilot scale in a curing tank located near environmental
department at SJCE campus, Mysore. The tank was not in use for the last one year and rain water
collected has supported various species including micro-algae simulating the natural fresh water
pond ecosystem. The samples collected from the pond showed the abundance of microalgae- diatoms
namely Nitzcheia, green algae- Chlorella, macro algae- nitella and duck weed (aquatic plant) ,
protozoan. The microscopic images were taken at intervals to identify the type and count of algae
(Motic 3.0 microscope).The dimesions of the tank is 9.7mx5.6mx2.5m and rice straw was added at
the dosage of 25g/m2 .The turbidity and the pH, DO values were recorded using pH meter and
Nepheloturbidity meter during the study.
The time required for the activation of rice straw is about 2 weeks [4], in the presence of
sunlight at the temperature 20°c. The pond was left undisturbed after adding the calculated dose of
rice straw for activation. On 0th day (before applying the straw) the algal cell count was recorded to
know the density or number of cell counts in drop of water. Algal cell counts were monitored for
every five days after straw activation (20 days) and was continued till the algal cell counts reduced to
zero or 1cell per drop of water.
Before application of the straw the cell count in the pond water was about 15-18 cells/drop
and after 20 days of application of the straw the cell count reduced to about 7-8 cells/drop. The cell
counts taken for every five days, showed declining trend. It was observed that for the 40th day after
application of the rice straw the algae cell count reached the value of 0-1cell/drop. During the
microscopic examination of the samples collected at multiple points in the pond at various intervals
(days), the shrinkage or reduction in cell size of diatoms species were observed. The increased
turbidity of water was observed which is due to wash out of cell components of the rice straw and
decreased pH might be due to the antialgal substances which are acidic in nature namely humic and
fulvic acids. The fig.1,2,3 below shows the pond used in research, rice straw applied to the pond and
image of macro algae nitella present in pond respectively.

3. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
45
Fig.1: Pond which is used in study (containing micro algae as wel as macro algae)
In the fig.2 below application of rice straw to the pond has been shown.
Fig. 2: Rice straw applied to the pond containing algae

4. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
46
Fig.3: The image of the Nitella (macro algae) in the pond
2.1 Mechanism of Rice Straw in Water
When straw is first placed in water, the soluble components of the straw are washed out,
causing water to turn a brown color [4]. Bacteria are the most dominant micro-organism at this stage
after about two weeks the dominant micro-flora change to fungi. This is when decomposition of
lignin and other cell wall components starts to occur. When straw rots, the cell wall components
decompose at different rates. Lignin is very persistent [3] and is likely to remain and be released into
the water as the other components decay. Decomposition of lignin leads to the production of a
soluble lignin and other decomposition products. These decomposition products are likely to be
transformed by bacterial and fungal enzyme activity before being released in to the surrounding
water. This mixture of compounds is transformed into fulvic and humic acids. These humic
substances are more easily referred to as Dissolved Organic Carbon or DOC. When light shines onto
water which contains humic substances, in the presence of dissolved oxygen, hydrogen peroxide is
eventually formed. High molecular weight DOC absorbs sunlight energy and can pass this energy to
dissolved oxygen molecules. The dissolved oxygen becomes unstable and decomposes into two
singlet oxygen radicals. The presence of a continuous supply of the right form of DOC creates
conditions whereby hydrogen peroxide and the other oxidizing agents can be continuously produced.
Hydrogen peroxide may be considered the main substance in controlling algae [3].
3. RESULTS AND DISCUSSIONS
During the microscopic examination it was observed that the algal cell counts decreased
gradually after applying the rice straw to the pond. Initially the sample was taken on 20th day after
applying the straw and further sampling was done for every five days and in addition microscopic
analysis showed shrinkage in the size of diatom cells. The algal cell count dropped to zero /drop of
water (sample taken at multiple points in a pond) on 35th day same and the same is depicted in
plate2.

5. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
47
However no such effect was observed on macro algae, but the visual appearance the nitella
(macro algae) which was green initially has turned to light brownish after applying the rice straw to
pond which indicates the decomposition of the macro algae in pond. From the present research it was
observed that rice straw was highly successful in controlling micro algae (diatoms, chlorella) in the
water. The microscopic images of the samples analyzed before and after applying the straw are
presented in plate 1 and 2.
Plate 1 Microscopic image of algal cell before applying Rice straw
The microscopic image of the sample taken on 35th day (plate 2) shows the decreased cell
density after applying the rice straw.
Plate 2 Microscopic images of algal cells after 35 days of applying the rice straw to pond water

6. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
48
4. CONCLUSIONS
From the present research work it can be concluded that rice straw successfully reduced the
micro algae i.e., diatoms in pond water, hence it is cheap economical and novel method for treating
fresh water. The optimum time period is fifteen days after the activation of straw. During the study
pH of the water decreased initially which is due to the wash out of straw components leading to
formation of fulvic acids and the same was analysed by recording the turbidity of the water which
increased from 4 to 8 NTU and further reduced towards end of the study period.
5. REFERENCE
[1] Ferrier M.D, Butler B.R, Terlizzi D.E and Lacouture R.V. “The effects of barley straw
(Hordeum vulgare) on the growth of freshwater algae”, Bioresource Technology, 96 1788–
1795 (2005)
[2] Mariraj Mohan S. “Comparative Study of Rice Straw and Ragi Straw for the Inhibition of
Algal Bloom in Fresh Water”, International Research Journal of Biological Science, Vol.
1(6), 31-37, October 2012
[3] Salwa M.,Abou El Ella1, Magdy M. Hosny, and Mohamed F. “Growth Inhibition Of bloom-forming
using Rice Straw In water courses (case study)”, Eleventh International Water
Technology Conference, IWTC11 2007 Sharm El-Sheikh, Egypt, P.O. Box 13621, Egypt
[4] Control of Algae using Barley Straw, Centre for ecology and hydrology, Natural research
sciences, 2000