Kapse Gaurav, Patoliya Pruthvi, Samadder S R
Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
Environ Monit Assess. 2017 Mar;189(3):133. doi: 10.1007/s10661-017-5844-3. Epub 2017 Feb 28.
The huge quantity of effluent generated in coal washing processes contains large amount of suspended and dissolved solids, clay minerals, coal fines and other impurities associated with raw coal. The present system of recirculation of the effluent is found to be ineffective in removing colloidal fines, which is the major part of the impurities present in washery effluent. Hence, there is a need for the assessment of a better technique for an efficient removal of these impurities. This study deals with detailed characterisation of coal washery effluent and fine particles present in it. For efficient removal of impurities, the suitability of biocoag-flocculation process using Moringa oleifera seed biomass as a natural coagulant was examined. Various doses of M. oleifera ranging from 0.2 to 3 mL/L were used in order to determine the optimal conditions. The impact of the variations in pH of the effluent (2-10), contact time (5-30 min), settlement time (5-50 min), temperature (10-50 °C) and the effluent dilution (1:0-1:5) was also assessed to optimise the treatment process. Post treatment analysis was carried out for determination of the different parameters such as pH, conductivity, turbidity, solids and settling velocity. Excellent reduction in turbidity (97.42%) and suspended solids (97.78%) was observed at an optimum dose of M. oleifera seed coagulant of 0.8 mL/L with an optimum contact time of 15 and at 20 min of settling time. In comparison with very few past studies of M. oleifera in the treatment of coal washery effluent with high dose and inadequate removal, this study stands to be a major highlight with low dose and high removal of the impurities. M. oleifera coagulant is considered to be an environment-friendly material, therefore, its application is recommended for simple and efficient treatment of coal washery effluent.
洗煤过程中产生的大量废水含有大量悬浮和溶解的固体、粘土矿物、煤粉以及与原煤相关的其他杂质。现有的废水循环系统在去除胶体细颗粒方面效果不佳，而胶体细颗粒是洗煤废水所含杂质的主要部分。因此，需要评估一种更好的技术来有效去除这些杂质。本研究涉及对洗煤废水及其所含细颗粒的详细表征。为了有效去除杂质，研究了使用辣木籽生物质作为天然混凝剂的生物混凝 - 絮凝工艺的适用性。使用了0.2至3 mL/L范围内的各种辣木剂量，以确定最佳条件。还评估了废水pH值（2 - 10）、接触时间（5 - 30分钟）、沉降时间（5 - 50分钟）、温度（10 - 50°C）和废水稀释度（1:0 - 1:5）的变化对优化处理过程的影响。进行了后处理分析，以确定不同参数，如pH值、电导率、浊度、固体含量和沉降速度。在辣木籽混凝剂最佳剂量为0.8 mL/L、最佳接触时间为15分钟且沉降时间为20分钟时，观察到浊度（97.42%）和悬浮固体（97.78%）有显著降低。与过去很少有关于高剂量且去除效果不佳的辣木处理洗煤废水的研究相比，本研究以低剂量和高杂质去除率成为一大亮点。辣木混凝剂被认为是一种环保材料，因此，建议将其应用于洗煤废水的简单有效处理。
