RBL (Research-Based Learning) : How Green Scallop's Shell Can Reduce The Pollution in Our Environment

    It is clear that we have environmental problems in this Earth. My country at least, Indonesia, which is known as a maritime country, have a problem in regulating waste in our coastline. Most of the waste is in the form of plastic or biological waste. The result can be seen that the water or the environment is disturbed and even can make a significance impact on biological scale. And if it left untreated, it maybe can go back into our body when we eat a fish or meat.

    So, I've made a research team to deepen our understanding about the possible waste and what we can do to fix them. The main theme is pollution on the sea with the main goal to reduce the effect of the pollution to the water as effective as possible. 

    How Green Scallop's Shell Can Reduce The Pollution in Our Environment

    Well, above is the main idea of this story. But before that, let's find how could I came into a conclusion like this.

    

 

    Perna Viridis sp. or usually known as Green Mussel is a type of mollusca that lived under the sea. Green mussel also called Pelecys which means 'flat-legged animal' and 'ax-shaped'. This animal have layered gills that make this animal have another call, Lamellibranchiata.

    Green Mussels are classified into Linnaeus taxonomy classification (1758) :

     Kingdom : Animalia

        Phylum : Mollusca

        Class : Bivalvia

        Ordo : Mytilida

        Family : Mytilidae    

        Genus : Perna

        Species : P. viridis

    The main habitat of Green Mussels are usually everything that is underwater and maintaining its life by clumping together with another green mussel. Usually, Green Mussels will grow well around 1-7 m in depth in a plankton-and-organic-matters-rich waters.

    

    The nutrient content of Green Mussels are composed of :

• 40.8% water,
• 21.9% protein, 
• 14.5% fat, 
• 18.5% carbohydrate, and
• 4.3% ash.

    All of those made the Green Mussel functional, but there is something left that is versatile to our topic today. That is the shell's content that contains Calcium Carbonate (CaCO3) within 90-95% of its total weight.

    

    The calcium carbonate that is contained in the shell can be used for a hydrolysis reaction and filtration process in the same time. In this case, when the calcium carbonate was exposed to contaminated / not contaminated water, it has the potential to do a chemical reaction called Hydrolysis. After the hydrolysis reaction is complete, then the side product - which is water and Carbon Dioxide gas - can be sorted in which we will take the water portion. This water that has undergone the hydrolysis reaction is cleaner, have a clear-looking condition, and has the potential to be drank. This is the main product from the reaction before that we are looking for.

    Beside that reason, me and my research team chose this organic matter because of the environmental problems on the coast of Indonesia. See, green mussels usually for consumption purpose and the waste is thrown away right at the place; the coastline. One of the waste is its shell and because of its composition, it has a hard time to decompose and in the result, making the coast polluted of green mussel's shell and have a distinct smell. So, me and my team decided to chose green mussels to clean the polluted water and cleaning the coastline at the same time.

    So, first up, we need to clarify the technical terms so we have the same understanding :

        Filtration 

    Filtration, from brittanica.com, is :

        the process in which solid particles in a liquid or gaseous fluid are removed by the use of a filter medium that permits the fluid to pass through but retains the solid particles.

    The meaning above emphasized the part 'solid particles' and 'the use of a filter medium'. In this research, solid particles means that everything that has the phase of solid int  the water and have the potential to be a pollutant. Solid particles can range from just piece of plastic to a tiny like-dust particle that can affect its former ecosystem, directly or indirectly. Its size can range from 10-6 mm (dust) to lower than 10-6 mm (dissolved solid).

    Afther that, there is 'the use of a filter medium' part which has the meaning of

    

    Here, we want to make the polluted water to be as clean and clear as possible, with additional goal to make the water to be drinkable. The way we (the researchers) think to filtrate the water is using Green Mussel's shell to filtrate with the hydrolysis reaction. This way, it is needed to make the shell's content to be able to react with the polluted water, thus filtrating the water indirectly through hydrolysis.

        Hydrolysis : Chemical Reaction

    Hydrolysis, from meriam-websterr.com, has the meaning of :

        a chemical process of decomposition involving the splitting of a bond and the addition of the hydrogen cation and the hydroxide anion of water

    To put it simply, hydrolysis is chemical reaction that breaks bonds between compounds and makes a new chemical substance. Hydrolysis happens when there is a salt compound that is made from a strong acid and a weak base or a strong base with a weak acid. This reactions usually happens spontaneously and create a new chemical substrate with a side product, either hydrogen ion or hydroxide ion. Beside that, this reaction can make the pollutant in the water to be retained, thus making the water cleaner and clearer

    

    Meanwhile we knew the main role of hydrolysis reaction, the side products before can also influence the property of the main product. If the side product is hydroxide ion, the main product will has a pH of above 7, thus making it has the property of a base solvent. But, if the side product is hydrogen ion, the main product will has a pH of lower than 7, thus making it has the property of an acid solvent. The end result can be predicted if we know what kind of salt that is reacting with the water.

    

    Salt compound (or usually called just 'salt') is a compound that is the main product from a reaction of acid and base. Beforehand, we already talked about how the resulting product can be predicted if we know what kind of salt that is reacting with the water. In this research, the salt is Calcium Carbonate (CaCO3) that is composed of  Calcium ion and Carbonate ion. The carbonate ion is an unstable ion and susceptible / prone to reacting with water, forming what is called the Carbonate Acid (H2CO3). When the 'unstable' ion is reacting with water, the reaction is called a Hydrolysis Reaction and in this case, it will have the side product of Hydrogen Ions. This condition will force make the water tends to has a pH range of lower than 7, thus making it an Acid Solvent.

    Then, How can a Green Mussel's shell be used to filtrate the contaminated water?

    The main theory for this is the hydrolysis reaction. This way, the Calcium Carbonate from the shell will react with the water and forming a weak acid that is Carbonate Acid (H2CO3). Then, because the carbonate acid is a product from a hydrolysis reaction and prone to dissolve in water, it will dissolve into water (in aqueous phase) and have a side product of Carbon Dioxide gas (CO2) that carries the micro-particles to the air. Meanwhile, the side product of the hydrolysis reaction, which is hydroxide ion, will make the end product (water) to have the property of a base solution. Thus, the filtration has ended and we have our filtration result. 

    In chemistry, the reaction between the carbonate ion with water can be described better with the image below : 

  

    Now, we know how the green mussel's shell can filtrate water, but still, it is needed some processing method before we can get the final result. Me and my team have thought about a method that use the same principles as we have discussed before. Technically speaking, the calcium carbonate inside the green mussel's shell needs to be reacted with water, so we thought about crushing the shell to pieces so the more calcium carbonate can be reacted with the polluted water. 

    Thus, let's jump into the methods :

• Choosing and collecting samples

        In my team's idea, we agreed to collect the samples from two places. The first one is the upstream of Cikapundung River at the National Forest of Ir. Juanda and the downstream of the same river at Jalan Pungkur, Ancol district or near Bobotoh Park.

• Green Mussel's shell media preparation

        Green Mussel's shells that have been collected then rinsed in clean water and then dried in the sun or using other device to remove its water content. After being dried, the shells needs to be crushed with the purpose of pulverization with two kind of resulting product : A portion that is coarse-shaped and other portion that is fine-dust. The comparison of fine powder and the coarse-shaped is 1 : 2.

• Parameter observation before experiment

        Observation of parameters before the experiment was carried out in order to determine the condition of water quality before carrying out filtration. The parameters used are visual (color), TDS (Total Dissolved Solid), pH (Power of Hydrogen) and turbidity.

• Filter Test

        The polluted water is put into the designed device that contains the fine-powder of shell, coarse-shaped shell, gravel, palm fiber and lastly is microfiber cloth (the last is optional). The product is collected to check the change in its property relative to the first condition.

• Parameter observation after experiment

        Water product that has been collected is put in again into the device and step 3-4 is conducted all over again. Note that every sequence has an effect to the product water and be sure to note the changes.

    Last question : How effective was it?

    The last question will be answered from the result of my research team experiment. Here the experiment was conducted in May 2022 and the base of this work is related to other thesis about related topics. Other than that, the process is repeated 3 times to see the effect on every try. So, it is wise to assume the data is accurate in Indonesia's terrain and advanced research is needed.

    So, let's go :

        Observation Data 

    From the data above, it can be seen that in some aspects, the value is decreasing while other aspects is increasing. To understand the meaning, below is the meaning of every aspects that is considered ;

• Color (PCU / Platinum - Cobalt Units) :

    A visual comparison using platinum cobalt standards where the range of water's color is going from light-yellow (the color of platinum mixed with water) to brown color (the color of cobalt mixed with water). It has the range of 0 - 500 where the standard drinking water has the PCU of no more than 15. 

• Turbidity (NTU / Nephelometric Turbidity unit) :

    here, turbidity has the meaning of cloudiness or haziness of a fluid caused by large numbers of individual particles. It is measured with Nephelometric Turbidity Unit which uses a specific device to measure the rate of turbidity in NT Units. Here it has the range of 0 - 1000 NTU where 0 is very bright and clear and 1000 is unbelievably dark and contaminated.

• Temperature : 

    The degree or intensity of heat present in a substance or object, especially as expressed according to a comparative scale and shown by a thermometer or perceived by touch. Here the units used is Celcius and measured with thermometer.

• pH (Power of Hydrogen)

    A scale used to determine the acidity or alkalinity of an aqueous solution. To measure pH, we (researcher team) use a device called pH meter and it has the range from 1-14 where 1 indicates the acidity is very high, meanwhile 14 indicates the alkalinity is very high.

• TDS (Total Dissolved Solid) :

    A measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular suspended form. It is usually use part per million (ppm) as a unit, but here, me and my research team decided to use mg/L to potray how many uknown substances in a litre of sample. Other than that, to measure TDS, we use a specific device that is a specified digital meter to measure the dissolved solids in sample as accurate as possible.

    As we can see, the result is divided into three sections based on the iteration of filtration. On the first, we can see the result is pretty low in PCU and Turbidity, but very high in TDS. It indicates that on the first try, the PCU and turbidity will drop throughout the iteration, meanwhile the TDS will increasing for each repetition of the experiment. 

        Final Observation Data

    On final repetition, we can definitely see a significant change in PCU and turbidity, but for increasing for the TDS aspect and pH. Here we can conclude that using this technology, it can make a clear and clean water, but not qualified as drinking water. 

    Also, from this experiment, the effective method is using a method that is more than 3 times iteration and uses more dense layer of fine-dust shell. It is hoped with this method, any contaminated water can reach the basic standard of clean water and in the future (maybe), make the water can be used as a substitute to drinking water so that everyone can have access to clean water.

    Conclusion

    From this experiment, we have presented the the main theory of how green mussel's shell can reduce the pollution in our environment and design a device that can suitable with the theory. Beside of that, the effect of processing clam shells containing calcium carbonate (CaCO3) has been proven to significantly reduce pollution in Cikapundung River water samples through aspects of TDS and NTU / Turbidity levels.

    For further research, we, researcher team, has a bunch of recommendation to offer :

1. The use of clam shells as a filtration medium has been shown to reduce pollutants in water. It is recommended that the use of green mussel shell filters will be more effective at river points that are commonly used for daily activities (bathing, washing and toileting) and organic waste disposal by the community.
2. At the time of sampling, it is desirable to use appropriate equipment in good conditions and places that tend to have stable weather to avoid data inaccuracies.
3. Ensure that the test kit design has a tap that is low enough to prevent build-up of water and other materials at the bottom of the test kit.
4. Use of a microfiber cloth attached to the inside of the faucet to avoid instability of the test data.
5. The use of a bulkhead consisting of a sturdy structure and separating material which is then installed to separate each filter material.
6. When testing the appliance using a water sample, it is advisable to pour slowly and wait until the water is not visible from above before opening the tap.
7. For how to process green mussels, it is hoped that there will be a machine to ease the procedure for smoothing green mussel shells.
8. It is hoped that there will be measurements of BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in further research to determine the effectiveness of clam shells in filtration in terms of BOD and COD parameters.
9. It is hoped that there will be further research on aspects of TDS and its use in plants.