Natural Coagulants as an Efficient Alternative to Chemical Ones for Continuous Treatment of Aquaculture Wastewater

The combined chemical and natural coagulant showed greater fluoride ion removal in synthetic hydrofluoric acid wastewater when compared to natural coagulant or chemical coagulant treatment alone. The impact of applying fibrous thin film on the coagulation activity was assessed in this study. In this study, a new chemical coagulant called Ecogent F-Loc was introduced. It can increase 40% of fluoride removal when combined with sodium aluminate. Combined chemical and natural coagulants gave the highest fluoride reduction using the Moringa Oleifera seed and eggshell with dosage of 100 ppm were 57% and 73%, respectively. When the chemical coagulant added with Moringa Oleifera seed, the fluoride removal efficiency increased from 50% to 77%. This showed that the combined chemical and natural coagulant showed similar coagulation effect as conventional chemical coagulant. In term of fibrous thin film, there is no significant effect on the coagulation activity of coagulant, but it helped to reduce the turbidity and coagulant residue in the synthetic wastewater and used to produce ionic solution for fluoride removal. In addition, the direct contact between particles and the impeller of Jar Test equipment can destroy the surface morphology of coagulant particles. With the support of the fibrous thin film, this challenge can be solved. In conclusion, the combined natural and chemical coagulant solutions can be used to substitute existing chemical treatment in fluoride wastewater treatment.

Synthetic coagulants currently used to treat dye wastewater in the water treatment industry has been found to produce large amounts of waste and is bad for the environment. The research then presents two different methods of preparing Hibiscus Sabdariffa as a natural coagulant which are direct method and freeze-drying method to possibly replace synthetic coagulant in treating dye wastewater. The two different methods of preparing natural coagulant Hibiscus Sabdariffa are compared in terms of protein retention and coagulation performance at removing dye from dye wastewater. This is to determine which method of preparation is better at preparing a Hibiscus Sabdariffa as a natural coagulant to be used in the water treatment industry. Three analysis are done to determine the optimum concentration of Hibiscus Sabdariffa powder and freeze-drying duration is based on (i) surface morphology, (ii) water solubility and (iii) water activity. Optimum concentration of Hibiscus Sabdariffa powder is 20wt% and 24-hour freeze-drying duration. Another analysis is done to compare protein retention of each methods of preparation using (iv) Fourier Transform Infrared (FTIR) spectroscopy testing. Protein in Hibiscus Sabdariffa prepared using freeze drying is completely retained based on Fourier Transform Infrared spectroscopy results. Supporting data of protein retention properties of freeze drying is proven by water activity in Hibiscus Sabdariffa powder is at 0.478 and below the 0.6 threshold value. Water activity of 0.478 means that there is not enough water content in Hibiscus Sabdariffa powder for microorganisms to grow and degrade the protein. Optimum coagulant dosage and pH value that Hibiscus Sabdariffa prepared using the two different methods best works in is determined based on two experiments called (v) effects of coagulant dosage on dye removal percentage and (vi) effect of pH value of preparation methods on colour removal percentage. Coagulation performance of both preparation methods are also determined using experiment (v) and (vi). Hibiscus Sabdariffa prepared using freeze drying has better coagulation performance with higher colour removal percentage at lower required coagulant dosage and higher dye removal percentage at varied pH values compared to direct method. As a result, freeze drying is better in terms of coagulation performance compared to direct method at preparing natural coagulant Hibiscus Sabdariffa. Coagulation performance of natural and chemical coagulant is compared using (vii) jar test comparison between natural and chemical coagulant on colour removal. This is to determine if coagulation performance of natural coagulant is comparable to chemical coagulant. Coagulation performance of natural coagulant is only slightly lower than synthetic coagulant at colour removal percentage of 91.2% compared to 92.3%. This makes the coagulation performance of natural coagulant comparable to synthetic coagulant allowing it to be an alternative to synthetic coagulant based on coagulation performance. Therefore, Life Cycle Analysis (LCA) will then be conducted to compare the better method of preparation of natural coagulant which is freeze-drying of natural coagulant Hibiscus Sabdariffa to chemical coagulant alum. Life Cycle Analysis done is to determine, evaluate and compare natural against chemical coagulant based on 3 sustainability aspects economic, environment and social aspects. This is to determine the feasibility of natural coagulant Hibiscus Sabdariffa in the water treatment industry on whether it is a possible alternative or replacement to the currently used synthetic coagulant alum. Based on Life Cycle Analysis natural coagulant is the better alternative compared to chemical coagulant based on impact towards the environment and health and well-being of society. However, the implementation of natural coagulant in the water treatment industry is still not feasible as production cost of natural coagulant is 126.86 times more expensive compared to chemical coagulant. As a result, currently Hibiscus Sabdariffa as a natural coagulant is not able to replace synthetic coagulant alum in the water treatment industry.

Molecular formula assignment of dissolved organic matter by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry using two non-targeted data processing approaches: A case study from recirculating aquaculture systems

Malaysia’s oleochemical processing industry uses crude palm oil as the main source of process feedstocks. Physical–chemical treatment methods such as coagulation and flocculation processes are widely used to pre-treat oleochemical effluent followed by biological treatment to meet Standard A/B as required by the Department of Environment (DOE). Established chemicals that are used include aluminium sulphate and iron chloride as coagulants while the aluminium chloride, iron salts, and polyelectrolytes are used as flocculants. The industry is in constant effort to look into alternative chemicals that are friendly to both human and environment. Natural coagulants such as wheat germ and chitosan are proposed to treat the effluent. The investigations related to the removal rate of turbidity and chemical oxygen demand (COD) between natural and chemical coagulants were carried out. The effluent samples were analysed with the aluminium content. The results showed that the optimum dosage of wheat germ, chitosan, aluminium sulphate and iron chloride were: 2000, 20, 167 and 169 mg/L respectively. The turbidity reduction efficiency percentage using the wheat germ, chitosan, aluminium sulphate and iron chloride were reported at 80.2 ± 30.2, 78.8 ± 32.9, 96.2 ± 2.0 and 90.3 ± 3.9% respectively. The COD reduction efficiency by using wheat germ, chitosan, aluminium sulphate, and iron chloride were reported at 11.4 ± 5.8, 15.7 ± 6.6, 15.7 ± 3.1 and 15.9 ± 3.3% respectively. The findings showed that the effluent samples from natural coagulation process contains of lower aluminium concentration (0.1 ± 0.1 and 0.2 ± 0.1 mg/L) as compared to effluent samples from chemical coagulation process with the aluminium concentration of 2.4 ± 0.4 and 5.5 ± 0.3 mg/L. Thus, the use of wheat germ and chitosan are less hazardous to human health and environment.

Water treatment is crucial for safe drinking water, especially in resource-limited regions. Natural coagulants like Moringa oleifera, Nirmali Seeds, and Azadirachta Indica are sustainable alternatives to chemical coagulants. They remove contaminants from water, promising potential for rural and developing areas. However, further research is needed to optimize their application and scale up for widespread adoption. Natural coagulants are environmentally friendly and costeffective, making them a promising future solution. Water treatment is critical in ensuring access to clean and safe water for various purposes. This paper explores the applications of natural and chemical coagulants in water treatment. Natural coagulants, derived from organic sources such as plants and seeds, offer environmentally friendly alternatives to conventional chemical coagulants. Chemical coagulants, on the other hand, provide rapid and effective removal of impurities through processes like charge neutralization and flocculation. The comparative effectiveness, costefficiency, and environmental impact of both types of coagulants are examined, highlighting their respective advantages and limitations. Additionally, emerging trends and innovations in coagulant technology are discussed, offering insights into the future of water treatment practices.

Coagulants are essential in purifying raw water for drinking water safety for consumers. Commonly, aluminium sulphate, a chemical coagulant, is used for water treatment. However, for long-term usage, chemical coagulants can be considered toxic and harmful to the environment due to the accumulation of this substance in the pipeline system, which can create severe health issues if consumed. The natural plant-based coagulant can be a substitute for a sustainable solution in the water treatment coagulation process. This research aimed to determine the efficiency of plant-based materials as coagulants in surface water treatment. Moringa oleifera and maize seeds were chosen as natural coagulants in this investigation since they are both locally available plant-based materials. Here, this research aims to study the ability of moringa oleifera seed and maize seed as plant-based coagulants in enhancing the effluent quality of the wastewater treatment plant of UiTM Dengkil Selangor. A jar test experiment was used to assess the capacity of moringa oleifera and maize as natural coagulants. The results comprise turbidity removal by 92% (mixed of moringa oleifera seed and maize seed), the chemical oxygen demand (COD) of 95% reduction rate using moringa oleifera seed. The biochemical oxygen demand (BOD) for 88% removal by moringa oleifera seed, ammonia-nitrogen removal of 12% (moringa oleifera seed) and total suspended solids (TSS) of 100% reduction rate using mixed moringa oleifera seed and maize seed for the effluent sample. Thus, it can be recognized that moringa oleifera and maize seeds can be an alternative solution to replace the chemical coagulants in the treatment systems.

Recirculating aquaculture systems (RAS) are a new alternative to traditional aquaculture approaches, allowing full control over the fish production conditions, while reducing the water demand. The reduction of water exchange leads to an accumulation of dissolved organic matter (DOM) that can have potential effects on water quality, fish welfare and system performance. Despite the growing awareness of DOM in aquaculture, scarce scientific information exists for understanding the composition and transformation of DOM in RAS. In this study, a non-targeted approach using ultra-performance liquid chromatography coupled to a hybrid quadrupole-time of flight mass spectrometer (UPLC-QTOF-MS) was used to characterize compositional changes of low molecular weight (LMW) DOM in RAS, when operated under two different feed types. A total of 1823 chemicals were identified and the majority of those contained a CHON chemical group in their structure. Changes in the composition of LMW-DOM in RAS waters were observed when the standard feed was switched to RAS feed. The DOM with the use of standard feed, consisted mainly of lignin/CRAM-like, CHO and CHOS chemical groups, while the DOM that used RAS feed, was mainly composed by unsaturated hydrocarbon, CHNO and CHNOS chemical groups. The Bray-Curtis dissimilarity cluster demonstrated differences in the composition of DOM from RAS and was associated to the type of feed used. When the RAS feed was used, the Kendrick mass defect plots of –CH2- homologous units in the pump-sump (after the water treatment) showed a high removal capacity for CHNO, CHNOS and halogenated chemicals with high Kendrick mass defect, KMD > 0.7. To our knowledge, this is the first report of LMW-DOM characterization of RAS by high-resolution mass spectrometry (HRMS).

Distillery spent wash is the residual liquid waste generated during the production of alcohol. The pollution caused from it is one of the most critical environmental problems. The distillery spent wash poses a serious threat to the water quality in several regions in and around the environment due to its characteristics such as high organic load, dark brown color, unpleasant odor, a high temperature, low pH, and high percentage of dissolved organic and inorganic matters which may be present as reducing sugars. The removal of organic compounds along with the color from distillery effluent is a challenging criterion to the sugar industries. The characterization of various physicochemical aspects of spent wash leads to the innovation of sugar wash, the dilution of the spent wash with sugar effluent. An attempt has been made to treat this industrial effluent with coagulating agents, chemical calcium hypochlorite, and alum and natural coagulant, Moringa oleifera L. seed powder for the reduction of the pollutant. Combined chemical and natural coagulant was found to be effective in sugar wash treatment with 82% of TDS and 84% of COD removal. Thus, the present investigation states that the distillery industrial effluent spent wash could be diluted with the sugar effluent to narrow down the pollutant load to 20% and also to avoid the use of water to dilute the effluent. Alum, the most widely used chemical coagulant was reported to produce Alzheimer’s disease. Hence, M. oleifera L. seed was substituted for the treatment along with the cost-effective chemical calcium hypochlorite. The combined CaOCl2 + Moringa seed (2.75 g + 5 g) treatment produced the best pollutant removal effect.

Introduction: The most important pollutant in surface water sources is turbidity. The aim of the study is to determine the most effective thyme plant extract as a natural coagulant to remove water turbidity and compare it with alum as a chemical coagulant.. Materials and Methods: In this study, plant extracts obtained from Thymus vulgaris (Tv), Thymus kotschyanus (Tk), and Thymus eriocalyx (Te) were used as natural coagulants for elimination of water turbidity. Then, the best of plant extract was confirmed by ninhydrin and FTIR analyses and the effect of simultaneous use of plant extract with chemical coagulant of aluminum sulfate (alum) was investigated in the hybrid ratio of 1:1, 2:1, and 1:2. Then, the effect of parameters include of pH, coagulant dose, turbidity removal efficiency, and the most suitable solvent for coagulant extraction were studied. Results: The results of this study showed that among the natural coagulants, Tv had a higher efficiency in elimination of water turbidity, and the highest amounts of turbidity elimination for Tv, alum, and Tv/alum hybrid coagulants was 94, 90, and 96, respectively. According to the results of this study, the most effective solvent for preparing plant extracts was 1M KCl solvent. Conclusion: The natural coagulant removes more turbidity from water than the chemical coagulant, and the simultaneous use of natural and chemical coagulants with a 1:1 ratio was more effective.

In land-based recirculating aquaculture systems (RAS), the accumulation of dissolved organic matter (DOM) can have detrimental effects on water quality impacting the system performance, microbial community, and consequently fish health and welfare. Ozone is used in the RAS water treatment process to improve water quality and remove DOM. However, little is known about the molecular composition of DOM in RAS and its transformation when exposed to ozone. In this study, we performed a detailed molecular characterization of DOM in RAS and explored its transformation induced by ozonation of RAS waters. Ultra-high resolution (UHR) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) was used to characterize the DOM matrix of RAS waters (pump-sump and tanks) and to evaluate its transformation by ozonation. The analysis of DOM extracted from makeup water and feed samples allowed for the determination of DOM sources in RAS prior to ozonation. The CHO and unsaturated group of compounds were the most abundant class found in water samples. On the contrary, the DOM from feed samples was unique and consisted mainly of CHO, CHON and unsaturated group of compounds. After the ozonation of RAS waters, humic-like and unsaturated compounds [positive oxygen subtracted double bond equivalent per carbon (DBE–O)/C)] were decomposed, particularly the CHO-DOM that contained fewer -CH2- features. Fulvic-like compounds and several hundred saturated compounds [negative (DBE–O)/C)] were formed post ozonation, particularly the CHON and CHONS group of compounds that were associated with fish diets, makeup waters and transformation products from the ozonation of the RAS waters. This study showed that the high accuracy of the ultra-high resolution FTICR MS can be applied to characterize and monitor the changes of DOM at a molecular level in RAS waters. To our knowledge, this is the first study where FTICR MS was incorporated for the characterization of DOM and its sources in RAS.

This review investigates the performance and the feasibility of the integration of an algal reactor in recirculating aquaculture systems (RAS). The number of studies related to this topic is limited, despite the apparent benefit of algae that can assimilate part of the inorganic waste in RAS. We identified two major challenges related to algal integration in RAS: first, the practical feasibility for improving nitrogen removal performance by algae in RAS; second, the economic feasibility of integrating an algal reactor in RAS. The main factors that determine high algal nitrogen removal rates are light and hydraulic retention time (HRT). Besides these factors, nitrogen-loading rates and RAS configuration could be important to ensure algal performance in nitrogen removal. Since nitrogen removal rate by algae is determined by HRT, this will affect the size (area or volume) of the algal reactor due to the time required for nutrient uptake by algae and large surface area needed to capture enough light. Constraints related to design, space, light capture, and reactor management could incur additional cost for aquaculture production. However, the increased purification of RAS wastewater could reduce the cost of water discharge in places where this is subject to levees. We believe that an improved understanding of how to manage the algal reactor and technological advancement of culturing algae, such as improved algal reactor design and low-cost artificial light, will increase the practical and economic feasibility of algal integration in RAS, thus improving the potential of mass cultivation of algae in RAS.

Dependency on sea food has increased owing to its nutrition as well as being complete food. As the production of seafood is enhanced through aquaculture, wastewater release has also improved. The composition of wastewater from aquaculture production has been a concern as it has oil and grease, organic content, etc., which makes its treatment challenging. The present study aims at treating aquaculture wastewater using two natural coagulants—chitin and seeds of Moringa oleifera. The efficiency of the natural coagulants was compared against inorganic chemical coagulant ferric chloride. A blended coagulant with two natural coagulants seeds of Moringa oleifera and chitin was also tested. Jar test apparatus was used in the current experiments, and four coagulant doses were tested against 3 pH ranges, from 6 to 8. The study results showed that the coagulants showed a 30–50% reduction in various physicochemical parameters. Further, the most promising result was obtained with the blended coagulants (di-blend) with 70–81% removal of total nitrogen and total phosphorus and the highest reduction of chloride with 95%. The Fourier-transform infrared spectroscopy showed functionalized groups responsible for coagulation, and X-ray powder diffraction analysis of the blended coagulant indicated the crystallinity and amorphous nature of the compounds. Scanning electron microscope analysis presented a firm and dense structure indicating adsorption of impurities onto the coagulant. Thus, it is evident that natural coagulants can be the solution for the challenges of aquaculture wastewater and specifically the di-blend used in the present is ascertained to be a promising solution.

High turbidity in water not only will reduce the quality of water itself but it can give impact to the ecosystem as well. In water treatment, coagulation and flocculation are the process involved in removing turbidity. Chemical coagulant such as aluminium sulfate (Alum) and ferric chloride are effective way and widely used in order to remove the turbidity in water. However, these chemical coagulants have a side effect in spite of the effectiveness in turbidity removal, the usage of alum and other chemical coagulants bring concerns due to its impact to the environment, human health and economy. Therefore, natural coagulant is another alternative for turbidity removal in water treatment. Natural coagulant is a plant-based coagulant which can be used to replace chemical coagulants. These coagulants are generally cheaper and safer than chemical counterparts. This research is conducted to compare the effectiveness of natural based coagulant made from Psophocarpus tetragonolobus and chemical coagulant in improving the quality of raw water. Findings from this study showed P. tetragonolobus can remove turbidity up to 60 percent with 40 ml, 1% solution. Therefore, P. tetragonolobus can be considered as a potential resource for natural coagulant.

A sustainable solution for aquaculture wastewater treatment: Evaluation of tannin-based and conventional coagulants.

The roles of algae in improving aquaculture water quality are well-established. However, the integration of algae in a recirculating aquaculture systems (RAS) is less popular mainly due to the large area required for photosynthesis. As science progresses, a growing number of reports are available on the benefits of algae to water quality and fish health. This motivated the author to investigate the effects of algae on a RAS stability, by measuring the water quality and the effects on bacterial community composition in a RAS. A review was conducted on nitrogen removal by algae and the operation of an algae reactor in a RAS. This showed that a RAS configuration influence algae performance by affecting nitrogen loading and nitrogen species (ammonium versus nitrate), cultivation methods (suspended versus attached) and environmental conditions (light, temperature, pH, oxygen, and carbon dioxide). Next, a periphytic microalga, Stigeoclonium nanum was cultured in suspension or immobilized. The growth and nitrogen uptake of S. nanum was higher when immobilized than when cultured in suspension. S. nanum preferred ammonia rather than nitrate as nitrogen species. Further effects of S. nanum on the RAS water quality (total ammonia nitrogen (TAN), nitrite, nitrate, and phosphate) were also investigated. No difference of TAN between the RAS with algae (RAS+A) and the RAS without algae (RAS-A) was observed. However, nitrite, nitrate and phosphate were significantly lower in the RAS+A than in the RAS-A. When the RAS systems were perturbed by an acute pH drop (from pH 7 to 4 over three hours), no significant difference was observed between the RAS+A and the RAS-A on the resistance towards the stressor. This was shown by an increase in the TAN and the nitrite concentration in both treatments after the perturbation. However, the algae helped the RAS+A to regain a low nitrite level faster than the RAS-A. The diversity of bacterial community between the RAS+A and the RAS-A was not different, while the composition of bacterial community was significantly different between the RAS+A and the RAS-A, thus influencing the functioning of the RAS.