Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge

Kadhim, Sajjad Hatim; Almansoory, Asia Fadhile; Al-Baldawi, Israa Abdulwahab; Abdullah, Siti Rozaimah Sheikh; Abbas, Karima F.; Imron, Muhammad Fauzul; Kurniawan, Setyo Budi

doi:10.3390/environments13020088

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Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge

by

Sajjad Hatim Kadhim

¹,

Asia Fadhile Almansoory

¹,

Israa Abdulwahab Al-Baldawi

²,

Siti Rozaimah Sheikh Abdullah

³

,

Karima F. Abbas

⁴,

Muhammad Fauzul Imron

^5,6,* and

Setyo Budi Kurniawan

⁷

¹

Department of Ecology, College of Science, University of Basrah, Basrah 61004, Iraq

²

Department of Civil Engineering, College of Engineering, University of Baghdad, Baghdad 10071, Iraq

³

Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM Bangi, Selangor 43600, Malaysia

⁴

Environmental Health Department, College of Applied Medical Science, University of Karbala, Karbala 56001, Iraq

⁵

Study Program of Environmental Engineering, Department of Biology, Faculty of Science and Technology, Universitas Airlangga, Kampus C UNAIR, Jalan Mulyorejo, Surabaya 60115, Indonesia

⁶

Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands

⁷

Research Centre for Environment and Clean Technologies, National Research and Innovation Agency (BRIN), Jakarta Pusat 10340, Indonesia

^*

Author to whom correspondence should be addressed.

Environments 2026, 13(2), 88; https://doi.org/10.3390/environments13020088

Submission received: 14 January 2026 / Revised: 2 February 2026 / Accepted: 2 February 2026 / Published: 4 February 2026

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Abstract

Treatment of wastewater effluent is essential to reduce environmental impact and keep surface water clean, meeting sustainable criteria. While plant-based coagulants are known for their eco-friendly profiles, their dual application for high-efficiency nutrient removal and subsequent sludge valorization in fish farm systems remain under-explored. Therefore, this study was conducted to determine the optimum conditions for using natural coagulants to recover nutrients from fish farm effluent. Two types of natural coagulants, Alhagi graecorum leaves and apricot seeds, were evaluated for the treatment and recovery of nutrients from fish farm effluent due to their high removal efficiency, non-toxicity, and cost-effectiveness. In this study, optimization was performed using Response Surface Methodology (RSM) with a Central Composite Design (CCD) to investigate the effects of three factors: coagulant concentration (1000–7000 mg/L), wastewater pH (5–9), and settling time (15–35 min). The primary responses measured were the removal efficiencies of phosphate (PO₄) and nitrate (NO₃). According to the CCD results, maximum removal efficiencies reached 92.63% and 73.49% for PO₄ and NO₃, respectively. The optimal conditions were identified as pH 5, 1000 mg/L coagulant concentration, and a 35 min settling time for A. graecorum, and pH 9, 1000 mg/L concentration, and a 15 min settling time for apricot seed. These findings establish the optimal conditions for using these natural substances as effective agents for sustainable wastewater treatment and nutrient recovery.

Keywords: coagulation; environmental pollution; flocculation; natural coagulant; nutrients recovery

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MDPI and ACS Style

Kadhim, S.H.; Almansoory, A.F.; Al-Baldawi, I.A.; Abdullah, S.R.S.; Abbas, K.F.; Imron, M.F.; Kurniawan, S.B. Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge. Environments 2026, 13, 88. https://doi.org/10.3390/environments13020088

AMA Style

Kadhim SH, Almansoory AF, Al-Baldawi IA, Abdullah SRS, Abbas KF, Imron MF, Kurniawan SB. Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge. Environments. 2026; 13(2):88. https://doi.org/10.3390/environments13020088

Chicago/Turabian Style

Kadhim, Sajjad Hatim, Asia Fadhile Almansoory, Israa Abdulwahab Al-Baldawi, Siti Rozaimah Sheikh Abdullah, Karima F. Abbas, Muhammad Fauzul Imron, and Setyo Budi Kurniawan. 2026. "Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge" Environments 13, no. 2: 88. https://doi.org/10.3390/environments13020088

APA Style

Kadhim, S. H., Almansoory, A. F., Al-Baldawi, I. A., Abdullah, S. R. S., Abbas, K. F., Imron, M. F., & Kurniawan, S. B. (2026). Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge. Environments, 13(2), 88. https://doi.org/10.3390/environments13020088

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Optimization of Coagulation–Flocculation Treatment for Fish Farm Effluent Using Green Coagulants and Recovery of the Produced Sludge

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