Lab-Scale Investigation of Fenton and Photo-Fenton Processes for Removal of Pollutants from Textile and Dye-Intermediate Industrial Wastewater, Ahmedabad Industrial Estate, Gujarat, India

This study investigates the physico-chemical characteristics and treatment efficacy of effluents from the Ahmedabad Industrial Estate, Gujarat, India, employing two Advanced Oxidation Processes: Fenton and Photo-Fenton. The study focused on a comprehensive suite of parameters, including pH, colour, turbidity, Total Suspended Solids, Total Solids, Total Dissolved Solids, Chemical Oxygen Demand, Biochemical Oxygen Demand, Chloride, Ammoniacal Nitrogen, Nitrate, Sulphate, and Phosphate. Experiments were conducted on 1-litre effluent samples at three volumetric ratios of ferrous ion to hydrogen peroxide: 1:10, 1:20, and 1:30. The Photo-Fenton process followed an identical protocol, with the addition of continuous UV light exposure to accelerate reaction kinetics. The results consistently demonstrated that pollutant removal efficiency correlated positively with the reactant ratio, with the 1:30 ratio yielding the highest performance across all parameters. Colour removal reached 74.11%, turbidity 83.62%, and TSS 72.49%. COD reduction was more modest, ranging between 9.09% and 31.97%. This stream showed significant susceptibility to Fenton oxidation. COD removal was remarkably high (up to 97.89%), while turbidity and TSS removal reached 98.50% and 92.60%, respectively. The inclusion of UV radiation enhanced the breakdown of pollutants, particularly in complex dye-intermediate matrices. TDS removal was notably improved, reaching 75.39%. Colour removal spanned 28.88% to 71.25%, with TSS reduction hitting 92.72%. This process proved highly efficient for organic degradation, achieving up to 96.61% COD removal. TSS removal peaked at 94.37%, confirming the process's viability for solid-liquid separation and organic mineralization. A recurring trend across both treatments was a negative removal value for sulphate. This is attributed to the addition of ferrous sulphate as a catalyst, which naturally increases the residual sulphate concentration in the effluent. While this is a by-product of the chemical dosing, it is a critical factor for post-treatment management. The study confirms that dye-intermediate effluents are generally more responsive to these oxidative treatments than textile effluents. The transition from the 1:10 to the 1:30 ratio consistently improved performance, suggesting that optimizing the peroxide dosage is paramount for maximum pollutant mineralization. Both Fenton and Photo-Fenton oxidation processes are highly effective, sustainable solutions for the pre-treatment of industrial wastewater in the Ahmedabad region. By leveraging the high oxidative potential of the hydroxyl radical, these methods offer a robust pathway for reducing the environmental footprint of textile and dye-intermediate manufacturing. Given the high removal efficiencies observed—particularly at the 1:30 ratio—these AOPs represent a viable, eco-friendly strategy to meet stringent discharge standards and promote water circularity in industrial zones.

本研究以印度古吉拉特邦艾哈迈达巴德工业区的工业废水为研究对象，考察其物理化学特性与处理效能，采用了两种高级氧化工艺（Advanced Oxidation Processes, AOPs）：芬顿（Fenton）法与光芬顿（Photo-Fenton）法。本研究涵盖了全面的参数指标体系，包括pH值、色度、浊度、总悬浮固体（Total Suspended Solids, TSS）、总固体（Total Solids, TS）、总溶解固体（Total Dissolved Solids, TDS）、化学需氧量（Chemical Oxygen Demand, COD）、生化需氧量（Biochemical Oxygen Demand, BOD）、氯化物、氨氮、硝酸盐、硫酸盐以及磷酸盐。实验以1升废水样品为载体，设置了亚铁离子与过氧化氢的三种体积比：1:10、1:20与1:30。光芬顿法遵循相同的实验流程，仅额外引入持续紫外光照以加速反应动力学。研究结果一致表明，污染物去除效率与反应物投加比呈正相关关系，其中1:30的投加比在所有参数指标下均取得了最优处理性能。色度去除率达74.11%，浊度去除率为83.62%，总悬浮固体去除率为72.49%。化学需氧量的削减幅度相对平缓，介于9.09%至31.97%之间。该类废水对芬顿氧化表现出显著的敏感性：化学需氧量去除率最高可达97.89%，浊度与总悬浮固体去除率分别达到98.50%与92.60%。引入紫外辐射可强化污染物的降解效果，尤其适用于成分复杂的染料中间体基质废水。总溶解固体去除率得到显著提升，最高可达75.39%。色度去除率介于28.88%至71.25%之间，总悬浮固体去除率达92.72%。该工艺对有机污染物的降解效果优异，化学需氧量去除率最高可达96.61%。总悬浮固体去除率峰值达94.37%，证实了该工艺在固液分离与有机矿化方面的可行性。两种处理工艺均出现了硫酸盐去除率为负值的共性现象，这是由于作为催化剂投加的硫酸亚铁会自然提升废水中的残留硫酸盐浓度。尽管这是化学投加过程中的副产物，但却是后处理管理环节的关键考量因素。本研究证实，染料中间体废水相较于纺织废水，通常对这类氧化处理具有更优的响应性。将投加比从1:10调整至1:30可持续提升处理性能，这表明优化过氧化氢投加量对于实现最大化污染物矿化至关重要。芬顿法与光芬顿氧化工艺均为艾哈迈达巴德地区工业废水预处理的高效、可持续解决方案。借助羟基自由基（hydroxyl radical）的强氧化潜能，这些方法可为纺织与染料中间体制造业降低环境影响提供可靠路径。鉴于实验中观测到的高去除效率——尤其是在1:30投加比条件下——这类高级氧化工艺代表了一种可行且环保的策略，可满足严苛的排放标准，并推动工业区内的水循环利用。