Investigating the Efficiency of Papaya and Date Dry Seeds as Natural Coagulants in the Wastewater Treatment Process

Industrial effluent contaminants comprise insoluble materials, heavy metals, and organic and inorganic substances. The textile sector needs help with waste management due to the various colours and chemicals involved. Coagulation-flocculation is commonly used to treat industrial effluent because it eliminates suspended particles, organic contaminants, turbidity, and colour. However, using chemical coagulants can lead to high expenses and generate large amounts of non-biodegradable waste and metallic residues in the treated water, which may introduce new pollution and disease risks. There is growing interest in a sustainable, non-toxic, and biodegradable alternative, specifically using natural coagulants from plant sources such as papaya dry seeds. This research examines the efficiency of various amounts of papaya seed coagulant (1.0 g, 1.5 g, 2.0 g, 2.5 g) with a consistent solvent of 1.0 M NaCl. SEM and XRD analyses were performed to characterise dry papaya seeds, revealing a porous and uneven surface structure. Assessments of Chemical Oxygen Demand (COD), turbidity, colour, and pH were used to determine the effectiveness of papaya seed purification on a textile wastewater sample. The results demonstrate that papaya dry seeds are highly effective coagulants. The optimal mass for papaya seed usage was 2.5 grams, achieving 92.72% effectiveness with a 20 ml coagulant dose. Furthermore, the best colour removal rate was 44.96% with a 25 ml dose at 2.5 grams of papaya seed mass. Additionally, the maximum COD reduction was observed with 2.0 grams of papaya seed mass and a 25 ml coagulant dose, achieving an 84.6% reduction. These findings highlight the potential benefits of using papaya seeds as organic coagulants for treating effluents from the textile industry.

The textile sector is grappling with the challenge of managing its waste, which is laden with diverse colours and chemicals. A standard method for treating this type of industrial effluent is coagulation-flocculation, recognised for its ability to reduce suspended solids, organic compounds, turbidity, and discolouration. However, the employment of chemical coagulants tends to produce considerable amounts of non-biodegradable sludge and metallic contaminants in the treated water, posing significant environmental and health hazards. A potential solution involves using plants or microbial substances instead of chemicals by dissolving dry seed date powder with NaCl to create a natural coagulant in saline solvent form. This study investigates the potential of using date seeds as a natural alternative to chemical coagulants in wastewater treatment. It evaluates the effectiveness of varying masses of date seeds (1.0g, 1.5g, 2.0g, 2.5g) with a consistent NaCl solvent concentration (1.0M) as a natural coagulant. Jar test was utilised with this extraction form of natural coagulant to determine its effectiveness in treating wastewater from the textile industry. The study assesses Chemical Oxygen Demand (COD), turbidity, colour, and pH to gauge the wastewater’s reaction to the date seed treatment. SEM and XRD analyses were conducted on the dry date seeds to understand their structure, revealing irregular shapes, macro-sized pores, and an amorphous material structure. Results indicated a significant reduction in water turbidity and colouration, with a 71.64% decrease in turbidity achieved using 25 ml of coagulant at a 2.5-gram dry seed mass. Similarly, a 2.0-gram seed mass was found to reduce COD by 80% with a 10 ml coagulant dosage. The most significant colour reduction was 27.70%, achieved with a 2.5-gram seed mass at a 25-ml dosage. This investigation sheds light on the potential for developing organic coagulants for industrial wastewater treatment, offering a more sustainable approach to managing environmental pollutants.

This research aims to use papaya seeds to make a Natural Coagulant. Natural coagulants are compounds that can cause coagulation in liquids, particularly in water treatment procedures, and can be derived from plant, animal, or microbiological sources. This particular substance was selected based on research showing it to be an effective coagulant in the water treatment process. The objectives of this project are to create non-chemical coagulants using natural resources like papaya seeds, create ecologically friendly coagulants from these materials, and measure the turbidity of water samples after utilizing these plant materials. Papaya seeds should then be dried, ground into smaller bits, and extracted. Filtering should be completed following extraction. Papaya seeds were used in three separate ratio tests. When the three papaya seed amounts are ready, they will be measured in quantities varied to approximate six beakers full of sample water from Lake Sultan Idris Shah Polytechnic for the jar test procedure. The papaya seeds will be extracted using 50 ml of distilled water. Of the three papaya seed ratios, the lowest turbidity value is 3.45 NTU for 10 grams, 1.77 NTU for 12 grams, and 4.97 NTU for 14 grams. The primary finding of this experiment is that papaya has qualities that can reduce the amount of turbidity in water. In conclusion, papaya seeds have demonstrated their ability to function as a natural coagulant and to lessen water turbidity.

The pretreatment process can be considered one of the important processes in wastewater treatment, especially coagulation process to decrease the strength of many pollutants. This paper focused on using powdered date seeds as natural coagulant in addition to chemical coagulants (alum and ferric chloride) to find the optimum dosage of each coagulant that makes efficient removal of turbidity and chemical oxygen demand (COD) from domestic wastewater as a pretreatment process, then finding the optimum combined dosages of date seeds with alum, date seeds with ferric chloride that make efficient removal for both pollutants. Concerning turbidity, the optimum dosage for date seeds, alum and ferric chloride were 40 mg/l (79%), 70 mg/l (84%) and 60 mg/l (82%) respectively. Concerning COD the optimum dosage for date seeds, alum, and ferric chloride were 40 mg/l (75%), 60 mg/l (83%) and 50 mg/l (86%). The study showed that the optimum combined dosage that made higher turbidity removal (95%) resulted from mixing 70 mg/l date seeds with 50 mg/l alum, while for higher COD removal 90% resulted from mixing 40 mg/l date sees with 70 mg/l ferric chloride.
 

Water purification is typically carried out using chemical coagulants like Tewes. localname for Aluminum sulfate. In many parts of the world experts are looking into coagulantmaterials derived from plants. Among many of them is the Moringa seeds. Moringa seedscontain water-soluble proteins, when crushed and dissolved in water it will form a positivelycharged solution. Electrophoreses Test proved that positively charged solution were alsoresulted from the use of Salak seeds and Papaya seed. The purpose of this study was toanalyze the differences in coagulation using Moringa (Moringa oleifera), Salak (Salaccazalacca), and Papaya seeds (Carica Papaya).The study was performed in a quasi-experimental set up exercising a pretest-posttestdesign. The object for the study was water sample taken from a river used by the communityin kecamatan Krembung for their water source. As much as 1000 ml of river water was used ineach test run. Test containers were treated with natural coagulants. Coagulant materials usedin the tests were Tawas powder, Moringa, Salak, and Papaya seeds at a dose-series of 50 ppmto 1000 ppm. The resulted data were analyzed using Kruskal - Wallis Test.There was a significant difference with regard to optimal dose of the natural coagulantsas well as the percentage of turbidity reduction. The optimal dose for Moringa seeds was 130ppm with a percentage of reduction at 97,3% that reduced turbidity down to 2.7 NTU. Theoptimal dose for Salak seeds was 100 ppm that resulted in a percentage reduction of 89,2%and reduced the turbidity down to 10.9 NTU. The optimal dose for Papaya seeds was 50 ppmwith a percentage of decline at 83,4% reducing the turbidity down to 16,7 NTU. Moringaseeds coagulant has maximum turbidity reducing capability, while the other two naturalcoagulants, Salak and Papaya seeds, were not in their maximum levels of turbidity reducingcapabilities.At a dose of 200 ppm Moringa seeds exhibited a greater ability as a coagulant inlowering water turbidity compared to the other natural coagulants, Salak seeds at a dose of100 ppm and Papaya seeds at a dose of 50 ppm. The study concluded that Moringa seeds canbe applied as a substitute for chemical coagulants provided they are used within 1 x 24 hours.Key Words : Turbidity and Coagulant

Coagulation and flocculation are an essential component of both the treatment of drinking water and the treatment of wastewater. The coagulant is one of the materials or substances that is added to the water to remove, stabilizes and causes colloidal particles to settle. Chemical coagulants such as aluminum sulphate (alum), ferric chloride, and synthetic polymers are the most commonly used coagulants in the industry due to their efficacy in turbidity removal. However, the use of chemical-based coagulants has had some negative impacts on human health and the environment, such as Alzheimer’s disease, and has produced a high volume of toxic sludge. In order to reduce negative impacts, this led to the discovery of an alternative to the natural coagulant (plant-based) for drinking water treatment. The coagulant used in this study is a combination of fruit waste containing citrus microcarpa peels and papaya seed with a ratio of 80:20 and 40:60. In addition to determining the potential of the composite natural coagulant, the optimal dosage and the effect of the mixing duration are also studied in order to determine the best mixing duration for each stage of the coagulation-flocculation process. Laboratory-scale studies using jar test experiments were conducted on surface water to determine the percentage of turbidity removal. Fruit waste was collected from the UiTM Pulau Pinang cafeteria, dried in the oven for 24 hours at a temperature of 105°C. The optimum dosage of composite natural coagulant is 90 mg/L using an 80:20 ratio of citrus microcarpa peels and papaya seeds with 97% of turbidity removal. The optimum mixing time is determined where the fast mixing time is 180 rpm for 3 minutes, the slow mixing time is 20 minutes with 10 rpm and the settling time is 30 minutes. The study shows that citrus microcarpa peels and papaya seeds have the potential to become effective natural coagulants in the future.

Papaya (Carica papaya L.) is an evergreen tropical fruit of the family Caricaceae, native to Mexico and Central America, and widely utilized in the food industry. Although the fruit pulp is processed into various food products, the seeds—accounting for nearly 15–20% of the fruit’s total weight—are often discarded, resulting in substantial agro-industrial waste. Due to their high moisture content, the seeds are highly perishable, leading to microbial spoilage and environmental concerns if not properly managed. However, papaya seeds are edible, safe, and nutritionally valuable, containing dietary fiber, protein, vitamin A, and essential fatty acids such as oleic acid, which aid in digestion, cholesterol regulation, and weight management. In addition to their nutritional composition, papaya seeds possess several bioactive properties, including antioxidant, antibacterial, anti-inflammatory, anti-diabetic, anti-obesity, anti-parasitic, wound-healing, and nephroprotective activities. Traditionally used in folk medicine for treating ailments such as dengue and malaria, papaya seeds have also gained attention as a functional food ingredient. Papaya seed powder has been incorporated into cookies, cupcakes, biscuits, hamburgers, and traditional snacks to enhance nutritional quality, while the oil and pectin extracted from the seeds hold potential for culinary, cosmetic, and pharmaceutical applications. From an industrial perspective, papaya seeds serve as natural preservatives, coagulants, and biosorbents, with emerging roles in biodiesel production, poultry feed, and soil bio-fumigation. Large-scale valorization of C. papaya seeds could promote sustainable waste management, circular bioeconomy, and functional food innovation. Hence, effective utilization of papaya seeds represents a promising approach to improve human health, nutrition, and environmental sustainability.

Textile wastewater contains a lot of pollutants which is hazardous if directly discharged. Coagulation and flocculation using inorganic salts were widely used to treat textile wastewater. However this method pose some drawbacks, such as high coagulant cost, large volume of sludge was produced, and potential health problems if the water is consumed. In this study we explore utilization of natural coagulant as an alternative to inorganic salts to treat textile wastewater. This study describes utilization of papaya seeds powder as a natural coagulant for synthetic textile wastewater of drimarene dark red (DDR) with initial concentration of 10 mg/L. The effect of coagulant dosage and pH to the %removal of colour in wastewater was studied using central composite design. The potential active functional groups in papaya seeds powder was characterized using Fourier Transform Infrared Spectroscopy (FTIR). It was found that papaya seeds powder contained -OH, -NH, C=O functional groups that indicate good potential as natural coagulant. The cubic model obtained was in good fit with experimental data, which was shown in R-squared value of 0.995. It was found that coagulant dosage, pH, and its interaction were significant to the removal of synthetic dye in wastewater. The decrease of pH gave higher %removal due to protonation of papaya seeds powder active coagulating agent resulting on better electrostatic interaction with dyes. The increase of dosage also gave increase in %removal until its optimum condition. After optimum condition, the %removal decreased due to colloid re-stabilization. The optimum condition was obtained at dosage of 0.57g/L and pH 1.97 with 84.77% of predicted colour removal and this result was in agreement with experimental response value.

Batik wastewater contains a high concentration of dye that comes from the batik dyeing process. In this study, papaya seeds were applied as a natural coagulant to reduce the concentration of remazol red in batik wastewater. Dried papaya seeds were characterized using Fourier Transform Infrared Spectroscopy (FTIR). The coagulation method used the batch method in the pH range of 1-6. The FTIR spectra showed that the papaya seeds contained compounds with -NH2 and -COOH functional groups. The results of coagulation showed that the pH of batik wastewater had an effect on the ability of papaya seeds to reduce the concentration of remazol red. The optimum pH condition was obtained at pH 2 with a decrease in the concentration of remazol red by 96.1%. The interaction that occurs between the coagulant of papaya seeds and the remazol red of batik wastewater is through electrostatic interactions.

Wastewater containing elevated turbidity levels can pose a significant risk if discharged directly into the environment. Conventional treatment involves chemical coagulants, presenting drawbacks like high cost, excessive sludge generation, and health risks To enhance sustainability in the treatment, it is essential to explore alternative methods that minimize environmental impact. Implementing natural coagulants, such as plant-based materials, can reduce reliance on costly inorganic salts and decrease sludge production. To reduce these drawbacks, alternative coagulants derived from natural sources are being explored for their potential to enhance sustainability while minimizing environmental impact. This research evaluates sustainable alternatives using natural coagulants—papaya seed powder, tamarind seeds, orange peels, and neem leaves—to treat municipal wastewater with an initial turbidity of 364 NTU. The effectiveness of these coagulants at different dosages was evaluated by jar tests, and the ideal dosage for each was identified. Along with turbidity reduction, the study also looked at the elimination of chemical and biochemical oxygen demands (BOD and COD). According to the findings, papaya seeds were able to remove up to 91.7% of the turbidity, 52% of the BOD, and 68% of the COD. 89.1% turbidity, 67% BOD, and 78% COD were eliminated by tamarind seeds. Neem leaves performed the best, removing 99.89% of the turbidity, 75% of the BOD, and 82% of the COD. Orange peels showed 66.89% turbidity reduction, 79% BOD removal, and 80% COD removal. The FTIR analysis showed functional group presence such as tannins and flavonoids in neem leaves, which likely contributed to their superior coagulation performance. Orange peels, being abundant and cost-effective, also demonstrated significant practical utility. These findings highlight the potential of natural coagulants as sustainable alternatives to conventional chemical treatments. The implications of this study suggest that plant-based coagulants, especially neem leaves and tamarind seeds, offer a viable, cost-effective solution for improving wastewater treatment while reducing environmental impact.

With the increased demand for textile products, the textile industry and its wastewaters have been increasing proportionally, making it one of the main sources of severe pollution problems worldwide. Textile wastewater treatment is one the most difficult environmental problems because it contains high color, biochemical oxygen demand (BOD), chemical oxygen demand (COD), pH, temperature, turbidity and toxic chemicals. The direct discharge of this wastewater without previous or proper treatment into the water bodies, like lakes, rivers, etc. pollutes the water affecting directly and indirectly the water. Coagulation/flocculation is one of the most widely used for wastewater treatment, as it is efficient and simple to operate. This process is used for the removal of suspended and dissolved solids, colloids and organic matter present in industrial wastewater. Natural coagulants have been attracting wide interest of researchers because they have the advantages of biodegradability, safe for human health, environmental friendly, generally toxic free and produce no secondary pollution. These coagulants are extracted from natural and renewable sources, such as microorganisms, animals or plants. Not only this, the sludge volume generated by the natural coagulants is smaller than chemical coagulants; it can further be treated biologically or can be disposed safely as soil conditioners because of their non-toxicity. The raw plant extracts are often available locally and hence, a low-cost alternative to chemical coagulants. In recent years, numerous studies on natural coagulants are growing and there is an urgent need to establish the use of natural low-cost coagulants for textile wastewater treatment. In this chapter, we show the characteristics of dyes and textile wastewater, emphasizing adverse impacts on environmental and human health and we mentioned some technologies for the textile wastewater treatment, highlighting the CF, since it is efficient, is easy to operate and is commonly used at the industries. We also have been discussed the physical-chemical concept of CF as well the major mechanisms involved at process. The usage of plant-based natural coagulants as alternative to chemical coagulants in the textile wastewater treatment is the goal of this chapter.

Abstract: Turbidity is the measure of relative clarity of a liquid. It is an optical characteristic of water and is a measurement of the amount of light that is scattered by material in the water when a lightis shined through the water sample. The higher the intensity of scattered light, the higher the turbidity Turbidity in the water creates both aesthetic and health issues. Surface water treatment plants remove particles because they can cause objectionable appearances, tastes, and odour and can interfere with disinfection. A wide range of natural coagulants, such as moringa seeds, banana peel, jatropha curcas, cassava peel starch, watermelon, pawpaw, beans, nirmali seeds, papaya seeds, organic dry hibiscus and okra have been studied previously. Natural coagulants in powder forms are usually added directly to wastewater. The most commonly used inorganic chemical coagulants in water treatment. Aluminium sulfate Al2(SO4)3 is the most commonly used chemical for coagulation in wastewater treatment. Additional commonly used coagulants include sodium aluminate NaAIO₂, ferric sulphate Fe2(SO4)3 and ferric chloride FeCl3.

Natural coagulants are proven to be a good alternative to conventional coagulants with the removal of various pollutants and are environmentally friendly. Despite its advantages, the least studies were carried out on local agro-wastes such as papaya seeds as natural coagulants concerning different operational factors. The study analyzes the main and interactions effect between the coagulant dosage, initial turbidity, and pH on deshelled Carica papaya seeds for turbid water treatment. A 2-level factorial design was used to investigate the main and interaction effects of the main operational factors, viz. coagulant dosage (50-200 mg/L), pH (3-7), and initial turbidity (100-500 NTU) on the turbidity removal of the synthetic turbid water. Based on individual performance, the results suggested that initial turbidity and pH are the most significant factors among the investigated operational factors. In combination, all interactions are significant, but the interaction between initial turbidity and pH is most significant, with 97.2% turbidity removal. Upon application of Carica papaya seed as a natural coagulant in water and wastewater treatment, these operating variables and their interactions are best to be considered.

Carica papaya seeds of a tropical tree comprise water-soluble and positively charged protein known as cystine protease which emerged as a putative coagulant in both water and wastewater treatments. Natural coagulants applications have been posed in many evaluation assays through many years owing to the difficulties raised by usage of chemical coagulants. It is indispensable to optimize process variables such as pH, turbidity, total dissolve solids (TDS), E. coli and coliforms counts accuracy to raise the efficiency of coagulation operation via employing C. papaya. Experimentally, employing jar tests supported by pretreatment, papaya seed protein as a natural coagulant, alum and solar disinfection to remove turbidity and bacteria was accomplished. The results revealed that the removal efficiency for turbidity was culminated up to 100% by incorporation of both alum and C. papaya seeds at lower dosages of coagulant about 0.2–0.6 mg/L at 30 min. A significant difference was found for paired samples correlations around 0.130 by p value = 0, among TDS, C. papaya and alum dosages and turbidity values. Employing a combined process resulted in turbidity and bacteria (most probable numbers of coliforms) removal around 100%. The highest efficiency of solar disinfection system possessed to fell the sunlight exposure period time by up to 2 h with 100% removal of E.coli and coliforms.

Dairy wastewater is a major environmental challenge owing to its high organic load, which poses risks to aquatic ecosystems and water quality. This study investigated the use of sustainable natural coagulants, specifically Carica papaya seeds, Citrus limetta peels, and Moringa oleifera, for treating dairy wastewater. These coagulants offer eco-friendly alternatives to conventional chemical methods. The Jar test method was applied to determine the maximum removal efficiencies for biochemical oxygen demand, total dissolved solids, and turbidity in dairy wastewater. Key parameters, including coagulant dosage (0.05-0.5g), contact time (10-30min), and pH (5-7), were optimized and statistically analyzed using Behnken design. The results demonstrated that Citrus limetta peels achieved 93.8% removal of biochemical oxygen demand, whereas Carica papaya seeds and Moringa oleifera showed 74% efficiency in reducing turbidity and total dissolved solids. This research supports sustainable wastewater management by promoting the use of agricultural waste materials for pollutant removal, thereby advancing circular economic practices within the dairy industry. The use of natural coagulants not only reduces the environmental impact of dairy wastewater, but also provides an accessible and cost-effective treatment option, recommending their broader application in wastewater treatment facilities.