The present disclosure generally relates to the field of wastewater treatment, more specifically the present disclosure relates to a method for treatment of methyl mercury contaminated water and soil. BACKGROUND OF THE INVENTION
Mercury (Hg) is a toxic heavy metal that has been regarded as one of the "ten leading chemicals of concern" (WHO, 2017). According to the United Nations Environment Programme (UNEP) report (UNEP, 2018), it is estimated that global mercury emissions to air from anthropogenic sources in 2015 were about 2220 tons. Among the anthropogenic sources, stationary combustion of fossil fuels accounts for 24% of the estimated emissions, primarily from coal-burning (21%). Other anthropogenic sources include cement production, iron and steel production, nonferrous metal smelting, gold production, chlor-alkali industry, waste disposal as well as direct production of mercury. Mercury contamination is of significant concern worldwide owing to its toxic effect on human health, for example damage to kidney and lung. Once transformed into its organomercuric forms such as methylmercury (MeHg), Hg acts as a potent neurotoxin which impairs brain function.
Once emitted to the atmosphere, Hg can be transported and thoroughly mixed in elemental form [Hg(0)] thereof. The major sink of elemental mercury is deposition to soil or water bodies after oxidation to divalent mercury [Hg(II)]. Aside from deposition, point sources of mercury contamination are the predominant cause of Hg pollution in soil and water. Like other heavy metals, mercury cannot be degraded in ecosystems, and therefore remediation should be based on removal or immobilization processes. Removal technologies involve the mechanism of adsorption, desorption, oxidation and reduction. The major aim of such technologies is to separate mercury from the contaminated media or transform toxic mercury species into less toxic ones. The most widely adopted immobilization techniques are stabilization and containment, which prevent mercury migration by chemical complexation or physical trapping, respectively.

In an instance, a Carbon Continental company based out in Uttar Pradesh state of India is a leading world producer of Carbon. When such carbon comes into contact with silica, it generates dangerous mineral i.e. Methyl Hg which is polluting Hindon River water and soil subjected for human consumption. Such a mineral is very dangerous that if a pregnant woman inhale the contaminated water, her newborn baby will be in deformed shape despite of best facilities provided to her during pregnancy. Such contamination has bad affect largely as 200-300 villages are dependent upon this particular source of water and soil.
There are different techniques for measurement of methyl mercury in water and/or soil. For example, distillation, aqueous ethylation, purge and temperature, and cold vapour atomic fluorescence spectrometry. Such methods involve determination of CHaHg in the range of 0.025 mg/1 and may be extended to higher levels by selection of smaller sample size for MDL(Method detection limit).. Another method is Laser Induced breakdown spectroscopy - (LIBS) for rapid remote measurement method for detection of metals in environment. Another method is a biological method involving Invertase-Glucose Oxidase-based biosensor. Such a biosensor can detect Hg compounds directly in aqueous solution in the range of 2-10 ppb.
There are many conventional arts which can remediate methyl mercury from the wastewater. For example, adsorption involving utilization of various adsorbents into the water has tendency to absorb the methyl mercury from the wastewater. The adsorbents have high surface area as well as high porosity and can adsorb through the formation of chelates. Examples of such adsorbents may include such as zeolites, flyash, biochar, and so on. However, every adsorbent may have own certain disadvantages associated therewith. For the remediation of Hg contaminated soil, Hg-containing waste or sludge, thermal desorption is being employed. In situ thermal desorption is encouraged these days, as there is no need to dig up the contaminated environmental media, especially the soil. Such a process involves inserting thermal conductive heating (TCH) elements into the soil in order to directly transfer heat. During the heating process, the increase of

the volatility of mercury results in the separation of mercury from the soil. However, the aforementioned methods have certain disadvantages associated therewith. For instance, high cost of such methods involving usage of activated carbon may be an obstacle for large-scale applications. In addition, long-term monitoring may be required while mercury stabilization and containment in soil on large sites.
Therefore, in light of the foregoing discussion, there exists a need for developing a safe and low cost method for treatment of water contaminated with methyl mercury, which is further safe for human, flora and fauna consumption.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, a composition for remediating methyl mercury contaminated water is disclosed. The composition includes an earthworm Eisenia fetida, algae consortia, and an adsorbent. The earthworm can feed on the algae consortia to survive in the water undergoing contamination therethrough. The algae consortium includes red algae, brown algae, and green algae. The treated water has COD in the range of 80-90%. The treated water has BOD>90%.
In another embodiment of the present invention, a method for remediating methyl mercury contaminated water is disclosed. The method includes introducing earthworm species Eisenia fetida into the contaminated water for absorption of methyl mercury therefrom. The method further includes providing essential nutrients to the earthworm through algae. Finally, the method involves absorbing other toxic elements in the contaminated water. The algae consortium includes red algae, brown algae, and green algae. The adsorbent is flyash. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the

embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The present invention discloses a composition for remediating methyl mercury contaminated water is disclosed. The composition includes an earthworm Eisenia fetida, algae consortia, and an adsorbent. The algae consortium includes red algae, brown algae, and green algae. The treated water has COD in the range of 80-90%. The treated water has BOD>90%.
The earthworm and the algae consortium play a role of the bio indicators. They both have tendency to control Hg toxicity and bioavailability, thereby ultimately evaluating hazardous situation. Earthworms are simple and well-studied creatures that can quickly provide indication of bioavailability. The species E.Fetidado can accumulate Hg. As the earthworm is exposed to mercury concentration therein, length thereof enhances. As the earthworm absorbs the mercury ions, methylation starts therein. However, capacity thereof can be enhanced by incorporation of other biological matter. The earthworm has certain capacity for the mercury intake. It needs to be enhanced so as to remediate large quantity of wastewater. Hence, the composition also includes algae consortium. The earthworm can feed on the algae consortia to survive in the water undergoing contamination therethrough. The consortium includes at least two of the algae selected from a group consisting of red, green, and brown. Such three algae subspecies differ in cell wall from each other, and together classified into marine algae. All the three algae have tendency to remediate methyl mercury also. For example, Ulva lactuca, a green microalgae has several functional groups such as hydroxyl, amino, sulfate and carbonyl, and performs best of all the algae in removing mercury. Such a process is known as biosorption. Hence, the algae plays a dual role- being feed intake for the earthworm and the removal of mercury from water.

A number of adsorbents can be employed, including such as but are not limited to zeolites, coal flyash, biochar, activated carbon, and so on. Most preferred adsorbent employed herein is flyash. The fly ash or coal fly ash (CFA) is a by-product of coal combustion of power plants.
Therefore, the earthworm body works as a biofilter and can remove the mercury from the water and soil within 5 days, and the treated water may have BOD by over 90%,COD by 80-90%,total dissolved solids (TDS) by 90-92% and the total suspended solid(TSS) by 90-95%. They can increase the hydraulic conductivity and natural aeration by granulating the clay particles. They also grind the silt and sand particles, increasing the total specific surface area, which enhances the ability to 'adsorb' the organic and inorganic from the wastewater. Such a process involves no sludge formation, requiring additional expenditure on landfill disposal. Such a process is an odour-free process, and the resulting vermifiltered water is clean and disinfected enough to be reused for farm irrigation and in parks and gardens. Experimental details
Three different soils were spiked with 12 different concentration of inorganic mercury (Hg). Sub-chronic Hg toxicity tests were carried out with Eisenia fetida in spiked soils by exposing the worms for 28 days following standard procedure. The toxicity results provided that Hg exerted less lethal effect on earthworm in acidic soil with higher organic carbon(S-3 Soil) where water soluble; and Hg fraction in soils with less organic carbon and higher pH. The concentration of Total Hg that caused 50% lethality to E.Fetida (Lc50) after 28 days of exposure in S-l,S-2 and S-3.Soils were 152 ,294 and 367 mg kg- 1 respectively. The average weight loss of E.Fetida in three soils ranges from 5-65%. The worms showed less weight loss in the organic carbon-rich soil (S-3) compared to less organic carbon containing soils(S-l and S-2). The bio concentration of Hg in E.Fetida increased with increased Hg concentrations. The highest bioaccumulation took place in the acidic soil with higher organic carbon contents with estimated bioaccumulation factors ranging from 2 to 7.7

For soil improvement - Earthworm needs the food and habitat provided by surface residue, and eats the fungi that become more common in no till soils. As earthworm population increases, they pull more and more residue into their burrows, helping to mix organic matter into the soil, improving soil structure and water infiltration, nutrient cycling and plant growth. They are not only indicators of healthy soils system but their presence is usually an indicator of a healthy system.
In another embodiment of the present invention, a method for remediating methyl mercury contaminated water is disclosed. The method involves introducing earthworm species Eisenia fetida into the contaminated water for absorption of methyl mercury therefrom. The method further includes providing essential nutrients to the earthworm through algae. Finally, the method involves absorbing other toxic elements in the contaminated water. The algae consortium includes red algae, brown algae, and green algae. The adsorbent is flyash.

We Claim
1. A composition for remediating methyl mercury contaminated water comprising an earthworm Eisenia fetida, algae consortia, and an adsorbent, wherein the earthworm feeds on the algae consortia to survive in the water undergoing contamination therethrough, enhancing capacity of the earthworm to intake the mercury ions from the wastewater.
2. The composition according to claim 1, wherein the algae consortia includes red algae, brown algae, and green algae.
3. The composition according to claim 1, wherein the treated water has COD in the range of 80-90%.
4. The composition according to claim 1, wherein the treated water has BOD>90%.
5. A method for remediating methyl mercury contaminated water, the method comprising:
introducing earthworm species Eisenia fetida into the contaminated water, and absorbing methyl mercury therefrom; providing essential nutrients to the earthworm through algae; and adsorbing other toxic elements in the contaminated water.
6. The method according to claim 5, wherein the algae consortia includes red algae, brown algae, and green algae.
7. The method according to claim 5, wherein the adsorbent is flyash.