BIOLOGICAL POTENTIAL OF AQUATIC WEEDS IN WASTEWATER TREATMENT (USING AZOLLA FILICULOIDES AND EICHHORNIA CRASSIPES)
Raj Amritam
M. Sc. in Environmental Sciences, Department of Environmental Sciences, Central University of Jharkhand, Brambe, Ranchi
Dr. Bhaskar Singh
Assistant Professor, Department of Environmental Sciences, Central University of Jharkhand, Brambe, Ranchi, Jharkhand -835205
Abstract - The term "aquatic weed" refers to a plant that invades a space and reduces its usefulness or enjoyment. This term is frequently used to refer to plants that invade a space excessively. in the water Posidonia australis, Eichhornia crassipes, and Azolla filiculoides are a few typical examples of water plants that can spread and become weeds. Aquatic weeds have the capacity to absorb excess contaminants such as organic and inorganic, heavy metals and pH of wastewater. They can flourish in ponds, lakes, streams, rivers, navigation channels, and seashores. Their expansion may be prompted by a number of things, including an abundance of nutrients in the water or the introduction of exotic species with a quick rate of growth. This study was carried out during April month and completed study by mid of month July. This studied showed that aquatic weeds in cement wastewater is very effective in improving it’s water quality in terms of pH and extra nutrient removal like nitrate and ammonia whose high concentration can lead to bad impact on soil health, vegetation and other aquatic life. This study was done on small tub using cement wastewater and weeds like Eichhornia crassipes and Azolla filiculoides. It mainly focuses on nutrient removal specially for Nitrate and Ammonia. Nitrate removal or it’s concentration must be decrease as it can change hemoglobin into methemoglobin. High level can change skin to grey colour or bluish colour and can cause serious health effect like weakness, fatigue, make water unfit for irrigation purposes.
1 INTRODUCTION
The biological potential of an organism is its maximal ability for reproduction under ideal environmental conditions (John P.
Rafferty, 2007). We would compare the amount of growth in terms of length and number that each aquatic weed is capable of producing in a given amount of time.
The biotic potential of the plants (weeds) that reproduce the most throughout that period is higher. Aquatic weeds have capacity to improve the water quality in terms of pH, heavy metals and extra nutrients (Kumar, P.B.A. Nanda, et al., 1995). This fact has been realized hundreds of years ago. As per many studies, it is proved that aquatic weeds have/exert cleansing effect on wastewater and running water or stable water. With the aid of aquatic weeds, a number of complicated and varying elements have improved the water quality. This requires physical, chemical and biological actions.
Even though the stems and leaves (or peteoles) of these weeds also play their own roles (Brown, Kathryn S., 1995).
Shallow reservoirs with floating or submerged aquatic plants make up treatment systems utilizing aquatic
weeds. The wastewater treatment systems that use duckweed and water hyacinth have been the most thoroughly examined (Lemna minor). Based on the most common plant types, treatment methods can be divided into two categories. The first kind makes use of floating plants or floating weeds, which are unique in that they can obtain the oxygen and carbon dioxide they require directly from the environment. These plants get their minerals from the water.
Aquatic weeds roots in water or in the soil having teeming with microbial activities which results into producing biopolymers, enzymes, hormones and other biomolecules which has been brought about physical, chemical and biological changes that result into treatment of water (Schnoor, Jerald L.,1995).
1.1 Functions of Aquatic Weeds in Wastewater Treatment
1. Plant part: Roots
It provides filtration and adsorption of solids.
It provides surface for the growth of bacteria.
In few cases, they release natural polymer which facilitate sedimentation.
2. Stem or leaves: Above water surface
This impact on effects of wind or water.
It facilitates transfer of gases and heat between atmosphere and water.
Some weeds/plants are very efficient oxygen pimps and has waste stabilization by serving as mini aerators.
Water Hyacinth: This comes under floating weeds and perennial weed that is native to South America. It has ability to adapt to disturbed environment. In water hyacinth, flowers are pollinated by long tongued bees and they can reproduce both sexually and clonally. The invasiveness of the hyacinth is related to its ability to clone itself and large patches are likely to all be part of the same genetic form.
1.2 Objective of the Study:
Physiochemical analysis of untreated and treated wastewater.
Nutrient removal of wastewater using Aquatic weeds.
Economic feasibility of Aquatic weeds.
2 REVIEW OF LITERATURE
Removal of wastewater through aquatic weed is an emerging technology applied for treatment of wastewater. It is suitable option notably in developing countries as it is simple, sustainable and cost effective.
In the present lab-based study the free- floating aquatic plant water lettuce (Pistia stratiotes) is used for treatment of parboiled rice mill wastewater having low pH, high chemical oxygen demand (COD), nitrogen and phosphate. In raw rice mill wastewater (undiluted) growth of water lettuce is found to be inhibited. Later on, two different dilution approaches (raw and facultative pond effluent 1:1; raw and tap water 1:1) are applied in order to effectively use this technology (Reed, S.C., Crites, R.W., and Middlebrooks, E.J., 1995) . In all cases a control (without plant) is maintained to compare the performance with the Aquatic Plant based Treatment (APT) system. In the APT
system results reveal that removal of soluble COD (SCOD), ammoniacal nitrogen (NH4-N), nitrate nitrogen (NO3- N) and soluble phosphorus (sol. P) are up to 65%, 98%, 70% and 65% respectively (Iteun and Ukpakha, 2011). The study highlights the efficacy of water lettuce in removing organics and nutrients from parboiled rice mill wastewater.
Different Aquatic plant species as potential remediation strategy for industrial wastewater. The results showed Water hyacinth achieve the highest removal efficiency of TN (89.4%), whereas water lettuce exhibited the highest removal efficiency for total phosphorus (93.6%) during the experiment (Bin Lu, Zhongshuo Xu, 2018). Regarding removal mechanism, the removal of Nitrogen and Phosphate by selected aquatic weeds primarily depend on plant adsorption.
In a different study, water hyacinths were raised in polishing ponds that contained secondary effluent from the wastewater treatment plant on the University of Florida campus. It was discovered that water hyacinth had a growth period of roughly 6 days when growing in secondary effluent as opposed to 12 days when growing naturally. With a depth of 1.4m, it was discovered that nutrient removal accounted for 80% of all nitrogen removal and around 50% of all phosphorus removal (4.5 ft). A loading parameter known as surface area per unit flow was discovered to have a direct association with the percent nutrient removal (DA Cornwell,1997).
Over the last decade, previous studies have shown that the mechanisms of nutrient uptake from wastewater could be advanced based on physiological, biological and physio chemical behaviours of plants in aquatic atmosphere (B.
Jiménez, 2008). Several scientists have examined the mechanisms of nutrient uptake by aquatic plants from wastewater systems
Efficiency of Pistia stratiotes in wastewater phytoremediation Summarize the prior research and contributions made on the efficiency of P. stratiotes in wastewater phytoremediation procedures in this paper. The effectiveness of P.
stratiotes in the phytoremediation of pre- cooked rice mill wastewater was investigated (Mukherjee et al).
Results of the aquatic-based plant treatment showed that up to 65% of the soluble COD (SCOD), 98% of the ammoniacal nitrogen (NH4-N), 70% of the nitrate nitrogen (NO3-N), and 65% of the soluble phosphorous were removed. This outcome demonstrates the effectiveness of P. striata plants in extracting extra organic nutrients from effluent from pre- cooked rice mills. Hanks et al.
investigated the abilities of P. stratiotes in the phytoremediation of synthetic wastewater containing varying quantities of silver nanoparticles (AgNP) and silver ions.
According to the findings of the investigations, P. stratiotes can survive in AgNP and ions < 0.02 mg L-1 by holding onto the contaminants inside the plant.
To attain the maximum contamination levels advised by the World Health Organization, researchers found that P.
stratiotes can operate as a phytoremediation agent in absorbing heavy metal nanoparticles (WHO). Nivetha et al. studied the effectiveness of P.
stratiotes plants in removing nitrogen and phosphate from sewage water. A plastic trough with various dimensions and specifications was used in the procedure to analyse nitrate, ammoniacal nitrogen, and phosphate levels. According to the results, P. stratiotes was able to remove 83.3 percent of nitrate and 84.8 percent of ammoniacal nitro.
Depending on the sort of enterprise producing it, the quality and volume of industrial effluent might vary greatly. It may or may not contain substances resistant to treatment, and it may or may not be highly biodegradable.
These include heavy metals or organic synthetic compounds, the quantity and quality of which may differ significantly between wastewater from developed and developing nations. The primary issue with industrial wastewater is the expanding (in terms of quantity and variety) amount of synthetic compounds present in and released into the environment (Angoua, 2008).
Industrial wastewater is the aqueous waste that occurs from materials being dissolved or suspended in water, usually during the use of water in an industrial production process or the cleaning activities that take place alongside that process. The removal of
those dissolved or suspended compounds is the goal of industrial wastewater treatment. Understanding how compounds are dissolved or suspended in water and then extrapolating probable chemical or physical actions that would reverse those processes is the greatest strategy for developing an effective and efficient technique of industrial wastewater treatment (Woodard & 2008) 3 METHODOLOGY
3.1 Study Area
The tub experiments for the above objective have been carried out under a temporary shed constructed in an area adjacent to Department of Environmental Sciences at Central University of Jharkhand, old campus, Brambe, Ranchi.
The aquatic weed samples for the study have been be collected were Eichhornia crassipes from Kanke Dam, and Azolla filliculoides from Birsa Agricultural University, Ranchi.
3.2 Sample Collection:
The determinants for sampling of wastewater and its monitoring may be classified as:
1. Conservative, which does not change with time.
2. Non conservative, which changes with time.
The first category has been be measured by taking representative samples for subsequent analysis in a laboratory, Department of Environmental Sciences, CUJ. (Singhirunnusorn and Stenstorm, 2009)
Fig. 3.1 Eichhornia crassipes (Water hyacinth)
Fig. 3.2 Azolla filiculoides 3.3 Experimental Design:
Fig. 3.3 Initial setup
There has been be 12 tub each for Cement wastewater. Then, we have placed Water weed plant into it (Water tub having wastewater), including two weeds namely- Water hyacinth and Azolla in each and having one replicate for each for its growth and observation for about sixty (60) days. Then after its suggested period, we had found out the data of respective experimental tub in terms of physiochemical criteria with plant growth (in cm) and compare the treated data with untreated wastewater data. Thus, we will able to find out the filtration potential and plant growth of aquatic weed for wastewater.
Objective 1:
Physiochemical analysis of untreated and treated wastewater
Method:
Sample was analyzed for pH by Digital pH meter
Fig. 3.4 Digital pH meter Table 2 pH of wastewater sample
Sample Initial
pH Final pH (After 60 Day) Distilled water 5.23 N.A.
Cement wastewater 6.61 N.A.
Control(R1) 6.67 7.35
Control(R2) 6.78 7.29
25% Conc(R1) 6.86 6.79
25% Conc(R2) 7.0 6.77
50% Conc(R1) 7.44 6.71
50% Conc(R2) 8.0 6.75
Weed used: Azolla filiculoides R1: Replicate 1
R2: Replicate 2
Table 2 Wastewater (cement) Sample Sample Initial
pH Final pH (After 60 days) Cement
wastewater
6.61 N.A.
Control (R1) 6.77 6.80 Control (R2) 6.78 7.01 25% Conc (R1) 6.86 6.85 25% Conc (R2) 7.0 6.88 50% Conc (R1) 7.44 7.00 50% Conc (R2) 8.00 7.15 Table. pH of wastewater Sample
Weed used: Eichhornia crassipes (Water hyacinth)
R1: Replicate 1 R2: Replicate 2 Objective 2:
Nutrient removal of wastewater using Aquatic Weeds.
Nitrate:
Nitrates, which are byproducts of organic matter decomposition, show that organic matter present in water has completely oxidized and is no longer dangerous. The detection of nitrates is crucial for managing the childhood condition known as methemoglobinemia that affects bodies of water.
Reagents:
Hydrochloride solution – Prepared by diluting 8.5 ml concentrated HCl and make up to 100 ml with distilled water
Stock nitrate solution – Prepared by dissolving 721.8 mg anhydrous potassium nitrate in 1 liter distilled water
Procedure:
An appropriate amount of the sample was obtained, filtered as necessary, and then well mixed with 1 ml (1N) HCl.
Nitrate calibration standards between 0 and 150 g N were created.
To measure nitrate, absorbance was read at a wavelength of 220 nm.
Calculation:
NO3 (mg/l) = N mg/l x 2.21 Ammonia:
When organic matter is broken down by microbes, ammonia is generated. As a result, both surface, including wastewater and groundwater contain it. Ammonia concentration exceeding a particular level is considered as toxic.
Reagents: Zinc sulphate is made by dissolving 10 grammes of zinc sulphate in 100 millilitres of distilled water.
To make sodium hydroxide, combine 24 g of sodium hydroxide with 100 ml of distilled water.
To make EDTA reagent, combine 50 g of EDTA with 60 ml of distilled water that also contains 10 g of NaOH. After cooling, the solution was diluted to 100 ml.
Nessler's reagent is made by combining 100 g of HgI2 and 70 g of KI with a tiny amount of water. This combination was added to a 160 g NaOH solution made in 500 ml of distilled water that had already cooled. The mixture was then diluted to 1 liter, let to sit for an overnight period, and the supernatant solution was retained in a colored bottle.
3.819 g of NH4Cl, which has been dried at 100 degrees Celsius, are dissolved in distilled water to create the standard ammonia solution.
Procedure:
Titrimetric Method:
A suitable aliquot of sample was taken in distillation apparatus and 0.5 ml phenolphthalein reagent followed by sodium hydroxide – sodium thiosulphate reagent were added till pH raised just above 8.2. Contents were distilled and 200 ml distillate was collected in 50 ml boric acid. Plain boric acid was used for colorimetric estimation and indicating boric acid was used for titrimetric estimation. The tip of the condenser was extended well below the level of boric acid solution.
After the distillation was completed, the concentration of ammonia was measure by nesslerisation and the distillate was titrated with 0.02 N H2SO4 till the indicator turned pale lavender colour.
`Similarly blank was prepared in the same way using distilled water instead of sample.
NH3 + H3BO3 - NH4 + H2BO3
H2BO3 + H+ - H3BO3
Calculation:
Where,
a = ml 0.2 N H2SO4 required for sample and
b = ml 0.2 N H2SO4 required for blank Objective 3:
Economic feasibility of Aquatic weeds:
Since they have been employed for centuries to filter water, aquatic weeds are crucial in the treatment of sewage.
Pollutant elimination is influenced by various environmental parameters, including pH, temperature, and plant features, as well as the length of exposure, waste composition, and pollutant concentration (species, root system etc.) It is important to remember, nevertheless, that other aquatic plant species have been successfully used in the phytoremediation of wastewater. The benefits and drawbacks of wastewater
treatment methods using
phytoremediation. Besides, aquatic plants such as free-floating plants (Pistia stratiotes, Salvinia molesta, Lemna spp., Azolla pinnata, Landoltia punctata,
Spirodela polyrhiza, Marsilea mutica, Eichhornia crassipes, and Riccia fluitans), submerged plants (Hygrophilla corymbosa, Najas marina, Ruppia maritima, Hydrilla verticillata, Egeria densa, Vallisneria americana and Myriophyllum aquaticum and emergent plants (Distichlis spicata, Cyperus spp., Imperata cylindrical, Iris virginica, Nuphar lutea, Justicia americana, Diodia virginiana, Nymphaea spp., Typha spp., Phragmites autralis and Hydrochloa caroliniensis) have been used for phytoremediation processes . In this context, existing records of aquatic plant species that has been utilized in phytoremediation of domestic, agricultural and industrial wastewater are utilized. Furthermore, free floating aquatic plants have become more suitable for phytoremediation due to their availability, high yield, and ease of stocking and harvesting
Some important economic feasibilities of Aquatic weeds are:
Environmental friendliness
Less carbon footprint
Low Capital requirements
Low energy requirements
Less secondary waste collection
Generation of feedstock for various mammals
The plants' ability to be harvested for the extraction of absorbed and stored pollutants such heavy metals, etc.; and their cost-effectiveness.
Nutrient recovery and wastewater reclamation
4 RESULT AND DISCUSSION Objective 1
Physiochemical analysis of Untreated and Treated Wastewater.
The potential uses of growing aquatic weeds for wastewater purification were examined on laboratory at Central University of Jharkhand, old campus, Brambe. Aquatic weeds that we have used like Water hyacinth and Azolla filiculoides in the study, the experiment has been made to assess the nutrient removal from cement wastewater using above mentioned weeds.
Table 1. Shows that pH of wastewater become suitable for irrigation purpose which is
between (6.70-7.29). These ranges of pH is considered as standard Ph for soil health and requirement of crops for its proper growth. Table 2. Shows that pH of cement wastewater become suitable for irrigation purpose which is between (6.80- 7.15). These ranges of pH, also considered as standard pH for soil health and requirement of crops for its proper growth.
Thus, from the above result of both the date, we came to conclude that aquatic weeds including both Azolla filiculoides and Eichhornia crassipes is useful natural materials for improving quality of water in terms of pH of cement wastewater.
Table 1 Wastewater (Cement) Sample No Sample Initial
pH Final pH (After 60 Day) 1 Distilled water 5.23 5.23 2 Cement
wastewater 6.61 6.61 3 Control(R1) 6.67 7.35 4 Control(R2) 6.78 7.29 5 25% Conc(R1) 6.86 6.79 6 25% Conc(R2) 7.0 6.77 7 50% Conc(R1) 7.44 6.71 8 50% Conc(R2) 8.0 6.75 Table pH of wastewater sample Weed used: Azolla filiculoids R1: Replicate 1
R2: Replicate 2
Table 2: Wastewater (cement) Sample S.
No Sample Initial
pH Final pH (After 60 Days) 1 Cement
wastewater 6.61 6.61
2 Control(R1) 6.77 6.80 3 Control(R2) 6.78 7.01 4 25% Conc(R1) 6.86 6.85 5 25% Conc(R2) 7.0 6.88 6 50% Conc(R1) 7.44 7.00 7 50% Conc(R2) 8.00 7.15 Table pH of wastewater Sample
Weed used: Eichhornia crassipes (Water hyacinth)
R1: Replicate 1 R2: Replicate 2 Objective 2:
Nutrient removal in wastewater using Aquatic weeds
Table 1 Nitrate Concentration Sample Type Initial
conc Final conc (After 60
Days) C.S (50 mg) Calibration
Sample 0.55 0.58 C.S (100 mg) Calibration 2.90 2.76
Sample C.S (150 mg) Calibration
Sample 2.96 1.94 Control
Sample 1 Water
hyacinth 2.16 1.37 Control
Sample 2 Water
hyacinth 2.18 1.36 Sample R1
(25% Conc) Water
hyacinth 2.90 1.5 Sample R2
(25% Conc) Water
hyacinth 2.94 1.5 Sample R1
(50% Conc) Water
hyacinth 3.15 1.84 Sample R2
(50% Conc) Water
hyacinth 3.16 2.00 Table 2 Nitrate Concentration (mg/l)
Sample Type Initial
Conc Final Conc (After 60
Days) Control Sample 1 Azolla 2.21 1.34 Control Sample 2 Azolla 2.18 1.36 Sample R1
(25% Conc) Azolla 2.90 2.02 Sample R2
(25% Conc) Azolla 2.94 1.87 Sample R1
(50% Conc)
Azolla 3.07 2.07 Sample R2
(50% Conc)
Azolla 3.07 2.10
Table 3 Ammonia Concentration (mg/l) Sample Type Initial
Conc Final Conc (After 60
Days) Control Sample 1 Azolla 19 mg/l 10 mg/l Control Sample 2 Azolla 19 mg/l 10.30 mg/l Sample R1
(25% Conc) Azolla 98 mg/l 26 mg/l Sample R2
(25% Conc) Azolla 98 mg/l 25.5 mg/l Sample R1
(50% Conc) Azolla 132 mg/l 30 mg/l Sample R2
(50% Conc) Azolla 132 mg/l 29.40 mg/l Table 4 Ammonia Concentration (mg/l)
Sample Type Initial Conc (mg/l)
Final Conc (mg/l)(After
60 Days) Control
Sample 1 Water
hyacinth 19 11.8
Control
Sample 2 Water
hyacinth 19 12
Sample R1
(25% Conc) Water
hyacinth 98 35
Sample R2 (25% Conc)
Water hyacinth
98 37
Sample R1
(50% Conc) Water
hyacinth 132 43
Sample R2
(50% Conc) Water
hyacinth 132 43.8
Final Figure Azolla filiculoides in experimental tub
Nitrate, which is made up of the element’s oxygen and nitrogen, is a crucial source of nitrogen for plant and animal life as well as the health of soil and crop life. However, too much nitrate in water can be harmful to human health as well as the health of soil and plant life because it affects their growth and denatures their own natural properties.
Nitrate concentration initially 3.10 mg/liter which comes to between 1.37 mg/liter to 2.0 mg/liter. This means aquatic weed including both Eichhornia crassipes and Azolla filiculoides have better tendency to absorb nutrient
No of weed (Azolla filiculoides) grown significantly from initial no 60 in each tub to almost 185-200, which shows that Cement wastewater is better medium for the growth of weeds.
5 CONCLUSION
Wastewater treatment is a technique used to clean up impurities from wastewater and turn it into effluent that can be reintroduced into the water cycle. The effluent has a minimal influence on the environment after re-joining the water cycle or is utilised in other ways. In a wastewater treatment facility, the treatment procedure is carried out. The right kind of wastewater treatment facility can handle treating a variety of wastewater types. In order to treat industrial wastewater, either a separate
industrial wastewater treatment plant is used, or a natural process, such as the help of aquatic weeds, is used.
Use of aquatic weeds are promising process or technique employed to remover or recover excess nutrients from wastewater and improve its quality.
This technique can also be used for recovery of nutrients such as nitrates and ammonia from wastewater that can be used in the production of fertilizers, struvite and food additives.
Significance of Aquatic weeds in wastewater treatment:
It helps in minimizing high pH value of cement wastewater as well as high nutrition like Nitrate, Ammonia, etc that can be utilized in useful purpose like Kitchen gardening.
Also, it has potential to reduce the cost of wastewater treatment which are going through mechanical process as it is pure natural method and do not require any electricity consumption.
It can use in mass level as it is environment friendly and do not harm nature but protect soil, pond and other water bodies from extreme pollutants and nutrient rich matter.
Aquatic weeds recover the concentration of Ammonia in wastewater from 132 mg/l to 32 mg/l which can further use for irrigation purposes or use as fertilizers, as Ammonia with final concentration (mentioned in table) is considered as useful for growth of crops.
From the above data, which is mentioned in the Table 3 and 4, clearly shows that Ammonia concentration removing capacity in Azolla filiculoides is better than Eichhornia crassipes.
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