Abstract

To ascertain the kind of pollution at concern, it is necessary to conduct a characterization of the wastewater. This process yields a broad range of information about the nature and concentration of the pollutants that are present and must be treated. This study aims to evaluate the parameters of the water quality of the vegetable market, industrial wastewater, and domestic wastewater collected from Rohtak, Haryana. In this study, 20 physico-chemical and biological parameters were analysed for the collected water sample from these three sources. These water quality parameters were discussed with respect to measurement techniques to analyse the quality of water. Most parameters values did not satisfy the standard acceptable limits for all three samples. However, chloride and fluoride were below the standard threshold and did not pollute the water to higher extent in these three sources. The major polluting component found in the vegetable market sample was the presence of a high concentration of nitrate (110 ppm) compared to other sources (27.85, 36.71 respectively). Nitrate directly comes from excessive usage of chemical fertilizer in agriculture, which is further carried in fruits and vegetables. Another contaminating factor found in these samples was the bacterial/fungal population indicated by CFU (colony forming unit), which directly measures the quantity of microorganisms in the given wastewater. Domestic wastewater showed the highest CFU ( that could be due to pathogens being excreted in feces. This also indicated the addition of runoff from animal waste into the water sources. Industrial sources, including slaughterhouses and food industries, could also be responsible for higher CFU. Interestingly, sample 1 (vegetable market) showed a very high nitrate component compared to the other two sources. Overall, this study suggested that wastewater from all three sites required to be treated for nitrate and bacterial removal before being disposed of in to public areas.

1. Introduction

Water is essential to our daily lives and the surrounding ecosystems. Moreover, it shapes the land and regulates the climate. Additionally, it is also used for irrigation, cooking, cleaning, and drinking ¹. Our body uses water to regulate body temperature, produce saliva, lubricate and cushion joints, protect the spinal cord and other sensitive tissues, and excrete waste through perspiration, urination, and defecation. Water is a renewable and manageable natural resource as it can be recycled, diverted, transported, and stored. All these properties endow water with great utility for humans and other forms of life on earth. Groundwater and surface water play a significant role in agriculture, hydropower generation, livestock production, industrial activities, forestry, fishing, and navigation, among other industries. It was found that about 0.5% of the earth's surface is covered by fresh water ²

Water quality was affected by agricultural activity, industrial waste, human activity, population growth, urbanisation, a weak management system, and other factors. Most agricultural activities involve excessive use of fertiliser and unsanitary conditions that endanger human health ³. Inadequate water resources have increasingly impeded water pollution control and quality enhancement ⁴. Moreover, volcanoes, algal blooms, storms, and earthquakes are the natural phenomena that cause a significant variation in water quality and ecological status ⁵. Major sources of water pollution include the discharge of domestic and industrial effluent waste, leakage from water tanks, marine dumping, radioactive waste, and atmospheric deposition. The accumulation of heavy metals and industrial waste in rivers and lakes can be hazardous to human health. Toxins released into water are the leading causes of immune suppression, failure of the reproductive system, and acute poisoning. Polluted water is also responsible for infectious diseases such as cholera, typhoid, gastroenteritis, diarrhoea, and kidney problems spread ⁶. It is estimated that 75-80% of water pollution is caused by domestic sewage. Wastes from industries such as sugar, textiles, electroplating, pesticide, and paper industries pollutes the water. In addition, due to the excessive algal growth that forms algal blooms, causes hypoxia and depletes faunal and floral diversity, polluted rivers emit an intolerable odour. It results in the destruction of mangroves, a decline in fish growth, and the demise of other aquatic organisms ⁷. Water pollution is caused by a wide variety of chemicals, pathogens, and physical changes, such as an increase in temperature, unpleasant odours, and discoloration. Numerous chemicals (calcium, sodium, nitrate, phosphate, magnesium, etc.) occur naturally in water. However, due to various types of waste, the amount of this chemical increases in the water and has negative effects on water quality and other aquatic life. Consequently, the quality of water is evaluated using various parameters ⁵.

Water quality testing parameters are categorized into physical, chemical, and biological attributes detected based on various components present in the water. There are a variety of physical criteria, including taste, colour, odour, temperature, turbidity, and electric conductivity, that are assessed to label the quality of water. Chemical parameters, consist of pH, alkalinity, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), chloride, fluoride, sodium, potassium, magnesium, sulphate, calcium, nitrate, phosphate, and salinity.

The assessment of water quality is of paramount concern for both public health and the comfort of aquatic life. Water quality parameters can guide us to assess the health of waterbodies and to determine the requirements of waterbodies that include aeration system installations, nutrient remediation applications, and treatments for algae and aquatic weeds. In addition, data obtained through assessment and monitoring of water quality provides scientific elements to aid in making health and environmental decisions. Water quality values act as effective and sensitive gauges of changes in the physical, chemical, or biological composition of the overall water status in water management practises. Water quality standards entail both descriptive statements and numerical values. This includes the basic rule for reporting water quality parameters by comparing the various analysed parameters to their regulatory limit and standard. Horten created the water quality index formula in 1965, which is used to evaluate the quality of water. It is a single parameter that rationalises values to subjective evaluation curves in order to combine different water quality attributes into a single numerical value ⁸.

The objective of this study is to ascertain the state of the water supply in those parts of the city that are considered to have the highest levels of water pollution. These areas include the Sunarian Chowk vegetable market, the Bhiwani Chungi industrial wastewater treatment plant, and the Kanheli wastewater treatment plant in Rohtak, Haryana. This evaluation of water quality enables a better insight into the underlying ecology of water, and analysis is required on water to verify that it complies with the standards and safety protocols that are essential for water to be free of toxins.

2. Material and Methods

Three distinct areas of the city of Rohtak that are considered to have highly contaminated water were sampled. These included the Sunarian chowk vegetable market (Sample 1), Bhiwani chungi industrial untreated wastewater collected from treatment plant (Sample 2), and Kanheli untreated domestic waste wastewater collected from treatment plant (Sample 3) Rohtak, Haryana. As per standard method of analysis, various water quality tests are conducted on collected samples, including pH, temperature, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, biodegradable ratio, CFU, TDS, fluoride, chloride, sodium, potassium, magnesium, sulphate, calcium, nitrate, phosphate, salinity, and resistivity (APHA 1989). Figure 1 shows the site of sample collection.

Temperature of samples analysed by Horiba LAQUA- F-74BW-G.

pH of samples was checked by Horiba LAQUA - F-74BW-G.

Electrical conductivity was tested by Horiba LAQUA- F-74BW-G.

Using the Winkler titration method, the dissolved oxygen of samples was evaluated. The samples are collected in a 300 ml BOD bottle containing undisturbed surface water. Further, 2 ml of MnSO₄ and 2 ml of alkali iodide azide in distilled water were added and close the stopper followed by thorough mixing, allowing the substances to precipitate (ppt). Later, 2 mL of concentrated H₂SO₄ was added and stirred until the ppt dissolved and a titrate was formed. In a conical flask, 200 ml of each sample and titrate against sodium thiosulfate at a concentration of 0.025 N were added until the pale-yellow colour turned blue and eventually colourless. The calculation was performed in accordance with the Central Pollution Control Board's (CPCB) Guide manual: water and wastewater analysis.

In BOD analysis, the DO of samples is measured at both the beginning and end of the process; on the day of sample collection and after 5 days of incubation, respectively. After dilution, the samples were incubated at 20°C to 25°C in a dark room or incubator. Later, phosphate buffer solution, magnesium sulphate solution, calcium chloride solution, ferric chloride solution, alkali, and acid solution of 1N, sodium sulphite solution, nitrification inhibitor, glucose- glutamic acid solution, ammonium chloride solution, and dilution water were used as reagents during the BOD calculation procedure. Supplementary Text S1 describes the detailed procedure for BOD calculation.

Potassium dichromate (K₂Cr₂O₇) solution, silver sulphate sulphuric acid solution, mercury sulphate solution, ferrous ammonium sulphate solution, and ferroin indicator are the required reagents to detect the COD. Supplementary Text S1 describes the detailed procedure for COD calculation.

It started with a porcelain dish with filter paper pre-weighted as W1. Later, up to 100 ml of sample was collected, filtered through filter paper, and placed in a pre-weighed porcelain dish. Sample was dried for 1 to 2 hours in a hot air oven that had been preheated to obtain a mass; then, the dish was cooled in a desiccator. The weight of the dish before it absorbs moisture was recorded as W2. Total TDS was determined by the standard method in accordance with the (CPCB) Guide manual: water and wastewater analysis.

It indicates the number of microorganisms present in a sample of water. In this method, collected samples were diluted or placed directly on an agar plate and incubated for 24 hours at 35°C to ensure proper microbial growth. The growth of microbial colonies in Petri dishes was measured by a colony counter (LABTRONICS- LT-37) after the incubation period. The CFU is determined in accordance with the Central Pollution Control Board's (CPCB) Guide manual: water and waste water analysis.

The colorimetric method and the ion selective method are typically used to analyse fluorides. However, due to the presence of interfering ions, the colorimetric technique is prone to error. Ion selective method is utilised for estimation of fluorides followed by CPCB manual guide: water and water analysis. Detail of the procedure is given supplementary text S1.

The sample volume for chloride determination must be 100 mL or a portion diluted to 100 mL. In a solution that is neutral or slightly alkaline, chloride was determined by titration with standard silver nitrate and potassium chromate as an indicator in accordance with the (CPCB) Guide manual: water and wastewater analysis. Detailed procedure was mentioned in supplementary text S1.

Standard sulphate solution was formed by dissolving 0.1479 g of anhydrous sodium sulphate, Na₂SO₄, in 10 ml of distilled water. Detailed procedure is given in supplementary text S1.

Methods for sodium analysis include the inductively coupled plasma method and the flame emission photometric method. In the flame emission photometric method, trace amounts of sodium can be determined by flame emission photometry at a wavelength of 589 nm.

It is also evaluated using a flame photometer. The necessary reagents and standards are deionized in distilled water. This water was used to prepare all reagents and calibration standards, as well as to dilute potassium stock solution. Standard method was used followed by CPCB guide manual: water and wastewater analysis. Detailed procedure is provided in supplementary text S1.

The total hardness of the water was calculated by the concentration of calcium and magnesium present in the water. Both are expressed in mg/L. An EDTA titration method was performed to measure the hardness of samples. Detailed methodology is provided in the supplementary text S1.

The UV Spectrophotometer method was used to determine the nitrate concentration. Detailed methodology is provided in supplementary text S1.

“Stannous chloride method” was applied to estimate phosphate concentration by using ammonium molybdate and stannous chloride.

3. Results and Discussions

Water quality is analysed by different parameters which provide valuable information to understand the quality of water in terms of numerical values and their standard limit. In this study 19 parameters were analysed that are listed in Table 1.

Temperature affects palatability, viscosity, solubility, odour and chemical reactions. Chlorination of water and biological oxygen demand are temperature dependent parameters. The standard water temperature is 10–15°C. All three locations have relatively similar temperatures of 29.4°C.

Conductivity quantifies the ability of an aqueous solution to conduct an electric current. The electric current carried by ions and their concentration as a whole. As ion concentration increases, conductivity also increases. Conductivity is measured in microohms per centimetre (U.S. unit) and milliSiemens per metre (S.I. unit). The standard limit of water conductivity is:

• Ultra-pure water: 5.5x 10^-6 S/m or 0.05 µS/cm

• Drinking water: 0.005-0.05 S/m or 200 -800 µS/cm

• Seawater: 5 S/m or 50 µS/cm

In our study, sample 1 has a conductivity of, 1162 µS/cm. This was attributed to the high range of dissolved ions. In samples 2 and 3, the conductivity was 2.63 µS/cm and 5.88 µS/cm, respectively, which proves the presence of fewer dissolved ions. As per the standard limit of conductivity, all samples were either higher or lower in conductivity compared to drinking water.

The pH parameter is used to determine whether water is basic or acidic. pH defines the negative concentration algorithm for hydrogen ions. Acidic water contains excess hydrogen ions, while basic water contains excess hydroxyl ions. On a scale ranging from 0 to 14, pH is neutral at 7. Less than 7 indicates the acidic nature of solutions, while greater than 7 indicates their alkaline nature. In our analysis, the pH of all three samples was acidic to neutral and ranged between 6.85 to 7.26. Sample 1 and Sample 2 have a pH of 6.86 and 6.85, respectively. This is considered near the acidic range, which proves it was contaminated with more pollutants. However, in sample 3, pH 7.26 showed its light alkaline nature.

It is the most important water quality test. Dissolved oxygen is the amount of oxygen required for aquatic life to exist. It diffuses from the atmosphere into the water as a by-product of the photosynthesis of algae and aquatic plants. The standard amount of dissolved oxygen varies according to the pressure, temperature, and salinity. The DO concentration is commonly calculated using the colorimetric method, the Winkler titration, and the electrometric method ^{9, 10}. Normal water has dissolved oxygen levels between 6.5 and 8 mg/L. In our analysis, the DO of samples 1, 2, and 3 was 2.9, 2.5, and 5.8 mg/L, respectively. This is a result of the low concentration of DO in each of the three samples relative to the standard limit. Moreover, samples 2 and 3 have extremely low levels of dissolved oxygen compared to sample 3, demonstrating that low levels of dissolved oxygen can be caused by high temperatures and the water's inability to handle the available oxygen. Low concentrations of dissolved oxygen may also indicate an increase in oxygen demand.

Biochemical oxygen demand refers to the amount of oxygen required for the survival of aerobic microorganisms in an aquatic environment, which decompose the organic matter in a given water sample at a specific temperature and time. The BOD value is measured in units consumed per litre. To determine the BOD of a water sample, it is incubated at 20°C for five days ^{11, 12}. Sample 1 in our study has a BOD concentration of 278 mg/L, while samples 2 and 3 have BOD concentrations of 276 mg/L and 375 mg/L, respectively. As the standard limit for BOD is 30 mg/L, it suggests that all three sites are highly polluted. This further indicated the high concentration of decomposed organic matter at all sites, with sample 3 being significantly impacted.

One of the parameters used to measure biodegradable and non-biodegradable substances in water is chemical oxygen demand. In other words, it is the measurement of the oxygen equivalent of organic matter susceptible to oxidation by a chemical oxidant in a water sample. Surface water has COD levels ranging from less than 20 mg/L in unpolluted water, 200 mg/L in sewage waste, and 100 mg/L to 60,000 mg/L in industrial waste ¹³. Sample 1 had a COD value of 985 mg/L, sample 2 had a COD value of 1210 mg/L, and sample 3 had a COD value of 1640 mg/L, indicating that all three sites are contaminated, with site 3 being the most polluted in terms of chemical oxygen demand. The presence of a greater amount of oxidising organic material in the sample, which reduces dissolved oxygen (DO) concentrations, is indicated by an increase in the concentration of chemical oxygen demand (COD). A reduction in DO can lead to anaerobic conditions.

The organic and inorganic salts that disperse in water and wastewater are implied by the total dissolved solids. The level of total dissolved solids (TDS) in water is affected by agricultural and industrial activities. An increase in TDS concentration is toxic to aquatic ecosystems. In salmonids, a high percentage of TDS reduces the turgidity of embryos, resulting in a loss of fertility. TDS is measured in parts per million (ppm), with fresh water sources containing less than 500 ppm, seawater containing 500-30,000 ppm, and brackish water containing 30-4000 ppm ^{14, 15}. In the observed samples, sample 1 has a TDS concentration of 582 mg/L, while samples 2 and 3 have TDS concentrations of 132 and 294 mg/L, respectively. Sample 1 has less dissolved solids than samples 2 and 3. High TDS levels indicate the presence of hazardous toxic minerals.

This parameter is used to determine the number of viable microorganism cells present in a given water sample. The standard limit of CFU for drinking water is 100 CFU/100 ml. Diseases like diarrhoea, giardiasis, and gastroenteritis are caused by the presence of pathogenic organisms in water ¹⁶. According to our analysis, sample 1 contains 4,000,000 CFU/ml, sample 2 contains 5,000,000 CFU/ml, and sample 3 contains 14,000,000 CFU/ml. This demonstrates that all samples are extremely contaminated with microorganisms. Compared to sample 1 and 2, site 3 is significantly more affected by the microorganism. Figure 2 shows the colony formation detected in all three samples.

Chlorides are naturally present in groundwater sources, but a higher chloride concentration indicates water contamination. It enters the freshwater system from numerous sources, such as chloride-containing rocks and agricultural run-off. In our samples, sample 1 consists of 82.33 ppm, sample 2 consists of 115.12 ppm, and sample 3 consists of 156.74 ppm. In all three samples, sample 3 had the most chlorides, which shows that chlorides had a big impact on this site. Moreover, the standard limit of chloride is 150 ppm for water and all the selected sites showed results below the limit, so it is concluded that chloride concentration did not affect the water quality of the selected location.

It is present in natural water. A high concentration of sulphate has a laxative effect (enhanced when sulphate is consumed with magnesium). Scaling in industrial water supplies causes odour and corrosion in wastewater treatment as a result of its reduction to hydrogen sulphide (H₂S). The standard limit for sulphate in water is 250 ppm, whereas the concentration of sulphate in our selected sites is extremely low, as in sample 1, 0.82 ppm, sample 2, 1.02 ppm, and sample 3, 1.21 ppm. This indicates that sulphate concentration did not effect on the quality of water in any of these sample.

Nitrate (NO₃) is a compound composed of nitrogen and oxygen. Nitrogen is produced when plants, animals, and human waste decompose. Nitrates facilitate the synthesis of amino acids and proteins, making them essential to plant growth. Nitrate is highly soluble in water; therefore, excess nitrate that is not used by plants can leach into groundwater. A high concentration of nitrate impairs water quality. The standard limit for nitrogen in water is 10 ppm. The first sample had 110.12 ppm, the second had 27.85 ppm, and the third was 36.71 ppm. All samples exceeded the standard limit, indicating contamination in the water, and sample 1 had a higher concentration of nitrate than samples 2 and 3, suggesting that selected sites were more affected by nitrate concentration than sample 2 and sample 3.

Phosphate is one of the main causative agents for eutrophication of water bodies. Agricultural run-off is mainly responsible for phosphate discharge into water bodies. The permissible limit of phosphate in streams is 0.1 mg/l before its discharge to protect natural water bodies. Sample 1 of our study had a high phosphate concentration recorded as 78.34 ppm as compared to sample 2 value 31.28 ppm and sample 3 value 53.6 ppm. All three samples had a high concentration of phosphate as compared to their permissible value.

The dental health benefits of a moderate concentration of fluoride ions (F) in drinking water. A concentration of approximately 1 mg/L prevents tooth decay in children. Dental fluorosis is the discoloration of teeth caused by excessive fluoride. The maximum allowed levels of fluoride in public water supplies vary depending on the local climate. In regions with warmer climates, the maximum acceptable concentration of fluoride in potable water is 1.4 mg/L, whereas in regions with colder climates, it is 2.4 mg/L. The safe level of fluoride for drinking water is between 0.5 and 1 parts per million (ppm), and according to our analysis, the fluoride content in sample 1 is 0.62 ppm, while in sample 2 and 3 it was estimated at 0.80 ppm and 0.85 ppm, respectively. This indicates that fluoride had no effect on the wastewater of these specific sites.

The amount of dissolved calcium and magnesium is a direct indication of water hardness. Calcium and magnesium are the predominant dissolved minerals in hard water. They enter water primarily through soil and rock contact, specifically limestone deposits. These ions exist as bicarbonates, sulphates, and infrequently, chlorides and nitrates. Typically, groundwater is harder than surface water. The standard hardness range for soft water is 10-50 ppm. In this study, sample 1 had a concentration of 55.66 ppm (Mg + Ca), sample 2 had a concentration of 23.18 ppm, and sample 3 had a concentration of 30.14 ppm. Sample 1 had slightly higher hardness than the standard value, indicating that hardness was found in the wastewater collected from this site, whereas sample 2 and sample 3 had hardness within the soft water range, indicating that hardness has no effect on the selected site's wastewater.

The salt concentration in water and wastewater is denoted by salinity. The average salinity of fresh water is 0.5 ppt, whereas the average salinity of oceans is 35 to 37 ppt. In this study, the salinity of the samples ranged from 0.70 to 3.58. All samples exceeded the standard range of salinity. Therefore, all samples were found saline; however, samples 3 and 2 were more contaminated on the salinity parameter.

The concentration of dissolved salts in water determines its electrical resistivity. If there is an abundance of dissolved salts, the water resistivity is low, whereas if the concentration of dissolved salts is low, the resistivity is high. This concludes that high resistivity reflects the pure form of water. The measuring unit of resistivity is ohms(Ω), pure water resistivity of water in ohms(Ω) is 20,0000,000 and 18.2 M Ω x cm. In this study, resistivity ranged from 0.858 to 0.171 in samples. Conferring to the standard value, the resistivity of studied samples was low, that indicated abundance of dissolved salts, and it affected the quality of water in all the contaminated sites.

A study in Poland by Puchlik et. al. showed that wastewater from vegetable and fruit processing industries had a BOD 860 to 3200 mg/L. However, in our study, BOD from the vegetable market (sample 1) was 278 mg/L. This indicated that the lower BOD in vegetable market wastewater compared to its corresponding industry. Similarly, COD in Puchlik et. al. study was 919 to 3700 mg/L that mapped with the COD we detected (985 mg/L) from the vegetable market sample. In this study, industrial and domestic wastewater had high COD (1210 and 1640 mg/L respectively) that matched more with the Puchlik et. al. study ¹⁷. Asia I. O et al. found that wastewater from the rubber industry had a conductivity of 187-380 Scm in Abraka, Nigeria. Conversely, in our study, the conductivity of industrial waste (sample 2) was 2.63 Scm. This indicated that lower conductivity was observed in industrial waste compared to the rubber factory industrial waste of Nigeria. Similarly, dissolved oxygen (DO) in Asia, I. O et al., was 4.10 to 7.10 mg/l, which when mapped with DO we detected was 2.5 from the industrial waste. Moreover, results of other analysis in Asia by I.O et al. showed that TDS, BOD, COD, nitrate, and CFU were 340-642 mg/L, 2210–/L, 2765-4721 mg/L, 0.99-2.63 mg/L, 600000000 CFU/100 ml respectively. These values are high as compared to our study, except for nitrate from the industrial waste sample (2). TDS was 1.32 mg/L, BOD was 276 mg/L, COD was 1210 mg/L, nitrate was 0.027 mg/L, and CFU/100 ml was 50000000 ¹⁸. The study at Bhubaneswar, Odisha, India by Dash et al., showed that domestic wastewater from municipal wastewater at three different sites had total hardness in S1 between 326-333 mg/L, in S2 275-280 mg/L, and in S3 it was 283.5-286.7 mg/L. However, in our study, the value of total hardness from domestic waste (sample 3) was 0.0314 mg/L. This indicated that a very low concentration of hardness was found in our soil as compared to Bhubaneswar S1, S2, and S3. Moreover, BOD at Bhubaneswar S1, S2, and S3 was 13, 114.5, and 108 mg/L respectively. The BOD we discovered in our sample 3 from domestic waste was 375. This indicated that there was higher BOD in domestic wastewater compared to its corresponding area ¹⁹. A study in Northern Nigeria, by Tanimu et al., showed that domestic wastewater effect in three reservoirs used for drinking water had an electrical conductivity (EC) of 45.1 to 573.33S/cm. However, in our study, the value of EC from domestic wastewater (sample2) was 5.88 S/cm. This indicated that the lower EC value in sample 2 compared to Northern Nigeria affected reservoirs. Similarly, dissolved oxygen (DO) in Tanimu et al.'s study ranged between 6.87 to 8.76 mg/L, while our detected DO from domestic wastewater was 5.8 mg/L ²⁰.

4. Conclusion

In Rohtak, Haryana, India, all three selected sites considered in this study are crucial to examine to find the quality of wastewater from vegetable market, industrial waste, and domestic waste. The water quality of selected sites is dependent on the type of pollutants and the discharge of waste material. The results of the water quality assessment indicated most of the tested parameters were elevated in the observed samples. However, sample 3 (domestic wastewater) showed higher values of BOD, COD, and CFU among all tested parameters, so high bacterial concentration could be considered a threatening outcome for public health. This clearly indicates hardness (calcium and magnesium concentration) were the most stressed parameters in sample 1 (vegetable market) during evaluation. Nitrate and phosphate contamination were also at their maximum in the vegetable market sample. Salinity was found to be highest most in sample 3 (domestic wastewater). This study strongly advocates the required water treatment process for all these three wastewater samples being before disposed of in public places as they consist of several chemical and biological agents.

References

Supplementary Text S1

Water was diluted by adding 1 ml of phosphate buffer solution, MgSO4, CaCl2, and FeCl3 was added to reached the desired volume of water in a bottle or container and brought it to a temperature between 20 and 25℃. Later, water was added to the sample in the BOD bottle, which was then immediately sealed to prevent aeration. One BOD bottle contained only dilution water was used as a blank, and both bottles was incubated for five days. After five days, the DO of the incubated water samples and the blank was analysed. BOD is computed using the formula:

D_o = Initial DO; D₅ = DO at Day five

Then, 1 ml of mercury sulphate solution was added and thoroughly mixed using a swirling motion. Later, five millilitres of potassium dichromate solution were added. Slowly, 15 ml of silver sulphate sulphuric solution was added to the flask, and reflex condenser was attached, the solution was digested on the plate for two hours. After digestion, flask was cooled and rinsed the condenser with 25 ml of distilled water, the water was collected from the rinsed condenser in the same flask. Further, 2-4 drops of ferroin indicator were added to the flask and titrate with 0.025 M ferrous ammonium sulphate solution to the endpoint till the sample's colour turns brown. Calculate the COD using the following formula:

Fluoride reacted with glass containers, an ion meter/pH metre, a calomel electrode, a fluoride-sensitive electrode, magnetic stirrer, and plastic containers are required equipment for this experiment. The electrodes were connected to the metre and the electrode slope was measured by the given instruction. TISAB added to 50 to 100 ml of sample placed in a 150 ml plastic beaker. The electrode was rinsed with distilled water and dried with tissue paper. A steady reading had been recorded by putting an electrode in a sample. The fluoride concentration in milligrams per litre was obtained directly from the specific ion metre.

Required equipment was porcelain dish, 200 mL, pipettes, burettes, and a glass rod. 50 ml of sample was taken, pH was adjusted to between 7.0 and 8.0, then 1 mL of K2Cr2O7 was added and titrated with standard AgNO3 solution until AgCrO4 precipitated as a pale red substance. Standardised AgNO3 against standard NaCl. Blank was established by distilled water was titrated using the same method. Chloride concentration was calculated with the formula:

Where, A = AgNO₃ required for sample, B = AgNO₃ required for blank, N = Normality of AgNO₃.

Turbidimetric analysis was performed, required equipment was a magnetic stirrer, a 420 nm colorimeter, a stopwatch, a 100 ml Nessler tube, and a 0. 2 to 0. 3 ml measured spoon. In a 250 ml Erlenmeyer flask sample was diluted in an appropriate volume to 100 ml. Then, 20 ml of the buffer solution was added and mixed thoroughly with helped of stirrer, then one spatula bacl2 crystal was added while continuously stirring. Stirring had been continued for 1-minute afterwards suspension was poured into the absorption cell of a photometer and turbidity was measured at 420 nm, in addition blank was taken without bacl2. Sulphate concentration calculated by following equation:

Required reagent stannous chloride solution is made by adding SnCl₂ into glycerol and ammonium molybdate solutions is prepared by adding ammonium molybdate into distilled water, then adding concentrated HNO₃ and dilution is done to prepare working solution. Readings were taken using UV-spectrophotometer.

Required equipment was flame photometer, required reagents and standard, deionized distilled watered, stock sodium solution, intermediate sodium solution, and standard sodium solution. The water sample was filtered through a 0.45 µm membrane. Sodium blank was prepared and calibrated standard for any of the following ranges: 0 to 1, 0 to 10, or 0 to 100 mg/L emission was measured at 589 nm. Beginning with the most concentrated calibration standard and progressing to the least concentrated. The process was repeated for a sufficient number of times with calibration standard and samples in ordered to obtained accurate reading for each solution calibrated curve generated by sodium standards. The intensity was measured by an internal measurement standard. Here, a bracketing approached was taken. Based on the calibration curve, selected and prepares sodium standards that immediately bracket the emission intensity of the sample. The emission intensities determined for the bracketing standards. The analysis was repeated on the paired standards and samples used for the equation from the standard calibration curve to determine the sodium concentration. Sodium concentration calculated used following equation:

Where, B was sodium mg/l in upper bracketing standard, A was sodium mg/l in lowered bracketing standard, b was emission intensity of upper bracketing standard, was emission intensity of lowered bracketing standard, s was emission intensity of sample, D was dilution ratio.

Membrane filter technique was used for the pre-treatment of collected samples. Direct intensity of the sample and blank was measured in a given range: 0 to 1. 0, 0 to 10, 0 to 100 mg/ and emission intensity was determined at 766. 5 nm. Aspired calibration standards and a sample allowed enough time to obtained a reliable average reading. Calibration curve was generated by potassium standards, calculated concentration of potassium used the following equation:

Apparatus required for the experiment was a conical flask of 100 ml, a burette, a pipette, and a spatula. The reagents and standards needed were a buffer solution, an inhibitor, mg CDTA, an eriochrome black t indicator, a murexide indicator, sodium hydroxide, a standard EDTA solution, and a standard calcium solution. 50 ml of sample was taken in a conical flask, then 2 ml of buffer solution and 1 ml of inhibitor was added to the sample. A pinched of eriochrome black t was added and titrated with standard EDTA until the wine turned blue. The quantity of EDTA required (A) was noted. The standard blank reagents were run volume noted as blank (B). Volume of EDTA was calculated required for the sample C = (A-B).

Calcium hardness test was performed by similar method Here, in 50 ml of sample was taken then 1ml of NaoH was added to raise the pH till 12.and followed by addition of a pinch of murexide indicator and titrated the EDTA till the pink colour changed to purple, and the amount of EDTA used was recorded. The blank concentration was determined in the same manner, and the total sample volume was determined by subtracting the EDTA volume from the blank concentration. Calcium and magnesium concentrations was calculated used the equation below:

Required apparatus was a Nessler tube of 50 ml, tissue paper, and a membrane filter. Required reagent and standard requirements was redistilled watered (used redistilled watered for the preparation of all solutions and dilutions), stock nitrate solution: (dissolve 721.8mg of anhydrous potassium nitrate and dilute to 1000ml with distilled watered. 1ml = 100 g N = 443g NO3), standard nitrate solution (dilute 100ml of stock nitrate solution with distilled watered to 1000ml. gNO3 n = 44. 3μgNO3) HCL 1N. %0 ml of sample was filtered, and added 1 ml of 1 N HCL and pH was adjusted. Absorbance or transmittance had been read at 220 nm and 275 nm. Set to 0 absorbance or 100% transmittance with distilled watered. Concentration calculated by: Nitrate N, mg/l = Nitrate-N / ml of sample.