Physiochemical Analysis of Drinking Water and Treatment with a Homemade Filter: A Case Study of Illu Abba Bor Zone, Ethiopia

The drinking water quality was evaluated in order to provide a continuous supply of clean and safe drinking water for the preservation of public health. The study area consists of three villages: Tulube, Seddo, and Serdo, all of which are located near Mettu town, which is about 550 kilometers south-west of Ethiopia's capital, Addis Ababa. The physical and chemical parameters of the collected drinking water samples were assessed, including pH, turbidity, conductivity, total suspended solids (TSS), total dissolved solids (TDS), and the presence of heavy metals. The samples were examined in the laboratory, and the findings were compared to the World Health Organization (WHO) standards. Almost all of the physiochemical indicators were safe and within the permissible limit for drinking water quality. However, lead ion concentrations were found to be above the WHO standards. An adsorbent produced from banana pseudostems was used to remove lead ions from drinking water. The equilibrium parameters were determined using the Langmuir adsorption isotherm. The drinking water was treated for 4 h in a homemade adsorption column composed of filter medium (sand, charcoal, and powder of treated banana pseudostem). The data revealed that lead ions removal was nearly 70%, but still above the WHO standards.


Introduction
Te oceans contain the majority of the world's water, which is unsuitable for human consumption. Only around 3% of the world's water is thought to be fresh, with 2.97% preserved in glaciers and ice caps. Te remaining 0.03% is collected in the form of surface and ground water for human use. A sufcient quantity of clean drinking water that is free of contamination is a key necessity for a sustainable human life [1,2]. Disease-causing microbes and chemical contaminants that are hazardous to one's health should not be present in drinking water. It should not be cloudy, high, or muddy, and it should adhere to the WHO guidelines. It should also be free of contaminants such as organic and inorganic pollutants, heavy metals, and pesticides [3]. It is critical that all people, particularly those living in developing nations, have access to safe, afordable drinking water [4]. Human activities such as urbanization, industrialization, agricultural activity, and other sorts of human activity have all contributed to an increase in the contamination of surface and ground water in recent decades [2][3][4][5]. Modernization, along with other human activity, continues to be a role in the transfer of waterborne diseases and has an impact on aquatic life [6,7]. Furthermore, it has the capacity to spread diseases in countries especially in the poor countries. Concerns about human health caused by waterborne infections are especially widespread in less developed nations such as Ethiopia, which lacks access to clean water of sufcient quality for human use. Te World Health Organization (WHO) estimates that polluted drinking water accounts for roughly 94% of the worldwide diarrheal sickness and 10% of the total disease burden [5][6][7]. Hence, access to safe drinking water is becoming increasingly crucial. Water bodies are commonly thought to be a source of metal buildup in aquatic animals, which can have long-term repercussions on both human health and the ecosystems in which they reside [7]. Researchers are currently investigating the presence of heavy metals in drinking water from both natural and anthropogenic sources [8][9][10]. Heavy metals have found their way into both surface and ground water. Te pervasiveness, toxicity, and possible harm to human health presented by these metals all have an impact on water quality [11,12]. Lead, zinc, copper, arsenic, cadmium, chromium, nickel, and uranium, as well as mercury, are heavy metals that cause the most concern. Te lead concentration in drinking water is a major concern. Even in low amounts, Pb can impair adults' and children's neurological systems. When lead-containing plumbing components decay in acidic or low-mineral water, lead can enter drinking water. Lead service lines are a signifcant source of lead [13].
Researchers across the world conducted studies to assess the drinking water quality. An experiment was carried out to see how a homemade flter afected turbidity, fuoride, pH, and temperature [2]. According to the study, fltering water signifcantly decreased physical, chemical, and biological pollutants. Te fltering device is small and light, making it ideal for travel. A comparative chemical study assessed the physical, chemical, and biological features of an Egyptian drinking water treatment plant [4]. Te evaluation includes fresh water from the canal infow, drinking water, and sand flter backwashing water. Tis report contains various ideas for policymakers that can save 20% of wasted water while also protecting canal waterways. To protect public health, the drinking water quality in Malaysia's Perak state was investigated [5]. Drinking water samples from residential and commercial regions around the state were tested for pH, turbidity, conductivity, TSS, TDS, and heavy metals in this context. Te values of the parameters were compared to the WHO standards as well as local criteria such as the National Drinking Water Quality Standard (NDWQS). Each metric satisfed the WHO and NDWQS requirements.
In Ethiopia, wells and springs are the primary sources of drinking water, supplying large urban and rural areas. Despite the fact that the government lacks regular and thorough water quality testing programs, there are rising indicators of water pollution concerns in some areas. Soil erosion, residential trash from urban and rural regions, and industrial wastes might all be important sources of pollution. Tere is not much adequate research done on drinking water standards and heavy metal pollution in the country. Endale et al. investigated Pb amounts in drinking water in Addis Ababa, Ethiopia's capital city. According to the study, Addis Ababa's drinking water is likely to be a source of lead exposure [13]. Alemu et al. [14] conducted a retrospective study on physicochemical quality of drinking water sources of Ethiopia. Te study used 983 water samples collected from diferent regions of the country for testing. Very high sodium and chloride concentrations were recorded in spring, tap, and well water sources of the region such as Somali, Afar, and Oromia. Te research was conducted by Mebrahtu and Zerabruk [15] to analyze the state of drinking water quality in the Tigray region of northern Ethiopia. Te primary goal of this paper is to determine the levels/concentrations of some physicochemical parameters and heavy metals and to compare the values with the national and international organization (such as WHO) recommended drinking water standards. Te results demonstrate that certain samples' electrical conductivity (EC), total dissolved solid (TDS), turbidity, and concentrations of various heavy metals (As, Cd, Cr, Fe, Ni, and Pb) are greater than the WHO standards.
Heavy metal removal can be achieved using a number of methods, including chemical precipitation, ion exchange, chemical oxidation, reduction, reverse osmosis, ultrafltration, electro dialysis, and adsorption [16][17][18]. Te great majority of them are traditional and pricey. Traditional water purifying technologies may be excessively expensive in rural or decentralized populations in developing nations. As a result, research into more efcient and cost-efective water treatment systems is critical in order to attain a safe level [17]. Previously, eforts were focused on designing a treatment that might minimize costs by utilizing particular processes or activities such as adsorption, fltration, and precipitation. Te adsorption technique is the most efcient, technically sophisticated, and well-known of these procedures, but the others have inherent limitations such as sludge development, poor efciency, sensitive working conditions, and expensive disposal [18][19][20][21][22][23][24][25][26][27][28][29][30][31].
Te goal of the present study is to look at the drinking water treatment and safety requirements in the Illu Abba Bor region. Te drinking water samples were collected at three diferent villages Tulube, Seddo, and Serdo. Tey are analyzed for important water quality characteristics such as pH, turbidity, conductivity, total suspended solids (TSS), total dissolved solids (TDS), and heavy metal presence as per the WHO standards. Te water was then treated with an adsorbent made from banana pseudostem. A homemade flter was constructed composed of flter media (sand, charcoal, and powder of banana pseudostem). Te atomic absorption spectroscopy (AAS) was used to evaluate the purifed water from the flter.

Narrative of the Study Area.
Te town of Mettu (8.2961°N, 35.5822°E) can be found in the Illu Abba Bor zone of the Oromia region of Ethiopia. It is about 550 km to the south-west of the capital city of Addis Ababa. Te water used for drinking in the Illu Abba Bor zone comes either from the river Gore or the river Sor. In order to conduct an investigation on the physiochemical characteristics of the drinking water, three diferent villages located close to Mettu town, i.e., Tulube, Seddo, and Serdo, were selected and the samples were gathered. Figure 1 represents the study area.

Analysis of Physiochemical Parameters.
Te cloudiness of water is referred to as turbidity. It is a measurement of light's ability to travel through water. Drinking water with excessive turbidity, or cloudiness, is both visually unappealing and potentially detrimental to one's health. In turbidity, pathogens can fnd food and shelter. Te turbidity was measured using a turbidity meter (Wag-WT3020, Halma PLC Company). Te pH of the water sample was measured using a digital pH meter (Hanna pH meter). Alkalinity in natural rivers is caused by the decomposition of CO 2 in water. Carbonates and bicarbonates are formed and then dissociated to form hydroxyl ions. Water's alkalinity is its ability to neutralize acid. In water treatment methods and defuoridation operations, the alkalinity value is crucial for estimating the disinfection dose. Te alkalinity was determined in accordance with APHA recommendations [32]. Te general hardness of the water was mostly caused by the dissolved calcium salt and magnesium salt from the nearby ores. Te hardness of the water will afect its taste. Water conductivity and total dissolved solids were measured in s/cm using a conductivity meter (WTW Inolab Cond 720). Water samples were tested for the content of calcium, magnesium, nitrates, phosphates, lead, copper, chromium, and zinc using a fame atomic absorption spectrometer (FAAS).

Preparation of Adsorbent from Banana Pseudostem.
Te samples of banana pseudostems were gathered from the local area. Te samples that were gathered were then divided into smaller pieces that ranged in size from 5 to 10 mm. After that, it was properly cleaned with regular water in order to get rid of the mud and any other particles that were undesirable. After that, the material was exposed to the sun for seven days in order to evaporate any surface water. In the end, the materials that had been dried went through a grinding and sifting process. After that, it was collected and put away for later use in an area that was sealed of with an airtight zip lock cover.

Batch Experiments for Adsorption Process.
In batch mode, 50 ml of the water sample is taken in a conical fask; the prepared adsorbent is added to it. Te parameters, agitation duration (min), adsorbent dosage (g/L), and initial lead concentration in aqueous solution (mg/L) for each sample will be modifed. Te samples are agitated for a specifed period. Te lead removal (%) by adsorption is calculated as where C t indicates the lead ion concentration at diferent time at equilibrium condition and C 0 indicates the initial lead ion concentration. Te adsorbed quantity on to the adsorbent surface was estimated using the equation below.
where C o and C e (mg/L) are initial and equilibrium lead ion concentrations in aqueous solution, respectively, W (g) is the mass of adsorbent, and V (L) is the volume of the solution. Te concentrations of the Pb (II) samples were determined using atomic absorption spectroscopy (AAS). All the experiments will be conducted in triplicate and the average values will be computed.

Adsorption
Isotherms. Te adsorption capacity was studied using Langmuir isotherm model. Te experimental adsorption data were used with this model. Most of the literature studies show that the Langmuir adsorption isotherm is extensively used for adsorption that occurs at specifc sites of a homogeneous adsorbent. Adsorption cannot take place once the adsorbate molecule occupies a site due to equilibrium being reached [10][11][12], and equation (3) describes the nonlinear form of the Langmuir model.
where C e (in mg/L) denotes the concentration equilibrium of the lead ions in the solution, q e (in mg/g) is the adsorption capacity, q max (in mg/g) is the maximum adsorption capacity, and k L (L/mg) is the Langmuir adsorption constant. International Journal of Analytical Chemistry 3 Te favorability or unfavorability of the adsorption system can be predicted by the equilibrium parameter RL, which is a dimensionless constant that is an essential characteristic of the Langmuir model. Te equilibrium parameter is determined by the following equation: Tis parameter suggests the type of isotherm, which may be irreversible (R L � 0), favorable (0 < R L < 1), or unfavorable (R L > 1).

Experimental Setup-Treatment of Drinking Water.
Te adsorption column made with an acrylic material was used for conducting the water purifcation. Te column is 59 cm tall and 10 cm wide. Figure S1 provides the design of the water flter used in the experiment. Adsorption chambers are flled with flter media as adsorbent in the adsorption setup. Te frst layer is composed of banana pseudostem powder, the second of charcoal powder, and the third of sand particles. Te treated water will pass through the top chamber, various layers, and fnally the fltrate will reach the bottom chamber. Te experiment was conducted and the fltrate was then analyzed using the AAS to determine the concentration of lead ions in the solution. Based on the (1), the percentage of removal can be calculated. Figures S2 and  S3 provide visual representation of the adsorbent and water flter. Table 1 summarizes the physiochemical parameters of drinking water based on the fndings of the examination of water samples obtained from three villages. Te samples were collected from tap water of residential and commercial places of these three villages. Te physiochemical parameters of the tested samples were mostly in agreement with the WHO standards [33]. However, the samples include considerable levels of lead, according to the fndings. Lead is extremely toxic in its natural habitat and has a signifcant negative infuence on the world's biodiversity. It is critical to remove lead and other heavy metals from water sources.

Efects of Contact Time.
In the process of adsorption, the contact time is an important parameter that ofers an optimal value for the maximum amount of adsorption that may occur at the surface of the adsorbent [20,21]. Terefore, in order to determine the efect that contact time has on the removal of lead ions, the experiments were carried out with varying time intervals ranging from 10-60 min, at an initial lead ion concentration of 30 mg/L and an adsorbent dosage of 0.5 g/L. Te fndings of the experiments are shown graphically in Figure 2. As can be seen from the fgure, the Pb (II) concentration adsorbed on the banana stem increases with the prolonged time. Te rate of the adsorption process initially depends on the mass transfer stage. Te initial stage is characterized by high intense adsorption due to the availability of active sites on the surface of the adsorbents, therefore large concentration gradient activates the process [21]. Similar kind of phenomena observed in the present study too. Te Pb (II) uptake was very fast initially, and the equilibrium attained at 60 min. Tus, in the following experiments, 60 min was selected as the optimal contact time.
Te fast adsorption suggests the process is mainly dominated by chemical adsorption rather than physical adsorption.

Efects of Adsorbent Dosage.
Te ideal adsorbent dosage is chosen carefully for efective and efcient removal of contaminants because adsorption is usually infuenced by the dosage of adsorbent. Te efect of dosage was studied using Pb (II) concentrations of 30 mg/L and the optimal contact time (60 min). Te dosage amount varied from 0.5 to 3 g/L. After agitating, fltration was done and the concentration of heavy metal ions in the fltrate was determined using the AAS. Te adsorbent dosage which adsorbed the maximum metal ions was considered to be the optimal dosage and was 0.25 g/L for all the metal ions ( Figure 3). Further increase in the adsorbent dose thereafter did have much infuence on the Pb (II) removal. Tis is due to overlapping of the adsorption sites because of overcrowding of adsorbent particles beyond the optimum dose and shielding of the adsorption sites [29,30].

Efects of Initial Concentration.
Experiments were conducted with varying beginning ion concentrations, ranging from 15 to 90 mg/L, with increments of 15 mg/L, for a total of 60 min, with the adsorbent dose set at 2.5 g/L. Tis was done so that the impact of the initial ion concentration could be determined. Te outcomes of the experiment are shown in graphical form in Figure 4. Te investigations that were discussed above provide evidence that the adsorption percentage drops when the initial ion concentration is increased. Te concentration of the Pb (II) with the highest uptake was taken to be optimal which was 10 mg/L.

Adsorption Isotherm.
Te nonlinear regression analysis for the Langmuir isotherm is shown in Figure 5. Te graph between C e and q e will be used to compute the adsorbent's maximum absorption capacity (q max ) for the adsorption of Pb (II) ions from water samples. Te Langmuir study yielded q max and k L values of 22.96 mg/g and 0.0415, respectively. R 2 (regression coefcient) was determined to be 0.943. Te equilibrium value R L varies from 0.194 to 0.7, showing that adsorption is favorable. Table 2 presents the removal uptake capacity of various adsorbents used for Pb removal.

Treatment of Drinking Water with Filter.
Te drinking water was purifed using a modifed homemade flter medium that was adjusted to include banana pseudostem powder, charcoal powder, and sand particles. Te drinking water sample will be run through the flter beds, and the   Figure 6. It demonstrates that, despite signifcant reductions in lead ion concentrations (about 70% in all three sites), the lead concentration remains greater than what the WHO considers safe. Te results indicate that the modifed handmade flter created for drinking water purifcation has a high potential for improvement. Devi et al. [34] conducted a similar study on the removal of fuoride, arsenic, and coliform bacteria from drinking water using a modifed handmade flter medium that incorporated crushed bricks. Te residual amounts of fuoride, arsenic, and coliform bacteria were determined to be within the WHO's permissible criteria. Mengistie et al. [2] conducted an experiment to test the efect of a modifed handmade flter on turbidity, fecal coliform, fuoride, as well as the flter's infuence on temperature and pH. Te study's fndings suggest that fltering fuoridated raw water with the material employed in the study might remove considerable levels of physical, chemical, and biological contaminants. Abdel-Shafy et al. [4] investigated and examined the physicochemical properties of drinking water, as well as developing a recycling sand flter. Te drinking water   treatment approach that is already in use is an efcient means of purifying easily available fresh water.

Conclusions
Drinking water samples from three distinct communities were analyzed for quality in accordance with the WHO and EPA guidelines. Te drinking water was judged to be safe, except for the presence of additional lead. Pb (II) ions were removed from drinking water using powdered banana stem as an adsorbent. Te important fndings from the batch trials are summarized below: the initial adsorbate concentration had a signifcant impact on how well the adsorption functioned (lead ions in solution). When the concentration of lead ions is higher to begin with, less lead is removed. Furthermore, both the amount of adsorbent used and the length of treatment contribute to an increase in adsorption capacity. According to the study's fndings, lead ion might be eliminated by using a low-cost agricultural waste product known as banana pseudostem. According to the Langmuir isotherm analysis, the adsorbent's maximal absorption capacity was 22.96 mg/g. Furthermore, a homemade water flter comprised of sand, charcoal, and banana stem was employed as a water flter to remove lead ions. Te adsorption took 4 h and efectively reduced the lead levels by 70%. Based on the research, we conclude that the homemade flter is successful in purifying drinking water; however, the concentration of lead ions need to be lower than the level set by the WHO. Terefore, it is vital to increase the efectiveness of the adsorption process by adjusting adsorption parameters such as treatment duration, the amount of adsorbent contained inside each column, and the particle size. In addition, the adsorbent has to be replaced every two days in order to keep it fresh. Tis will allow the adsorption process to be more efective while also preventing the growth of germs and other types of pollution.

Data Availability
Te data used to support the fndings of this study are included within the tables and fgures.

Conflicts of Interest
Te authors declare that they have no conficts of interest. Figure S1 provides the design of the water flter used in the experiment. Te column contains diferent chambers. Te height of individual chambers is described in Figure S1. Te frst three chambers contain adsorbent materials. As described in Figure S1, layer 1 is flled with banana pseudostem powder, layer 2 is flled with charcoal powder, and layer 3 is flled with sand particles. Te treated water will pass through the top chamber, then diferent layers, and fnally the fltrate will reach the bottom chamber. Te visual representation of pseudo-banana stems collected and processed is represented in Figure S2. Figure S3 represents the fltering materials and adsorption column. (Supplementary Materials)