Abstract

This study aimed at studying the phycoremediation of petroleum-contaminated water using microalgae biofilm cultured in nutrient-rich water. Microalgae biofilm was grown in a photobioreactor containing water rich in calcium nitrate, manganese chloride, sodium potassium tartrate, calcium phosphate, and ammonium sulfate. Petroleum contaminated water was poured into a photobioreactor, and the substrate containing microalgae biofilm was inserted into the photobioreactor and allowed for eight weeks for biofilm formation. Physicochemical parameters (pH, turbidity, conductivity, sulfate, alkalinity, chloride, TDS, TSS, nitrate, salinity, iron, potassium, phosphate, chlorine, chromium, magnesium, zinc, COD, BOD, and total petroleum hydrocarbon (TPH) of the petroleum contaminated water before and after treatment were determined. The microalgae biofilm used for the treatment was characterized before and after treatment using a Scanning Electron Microscope, X-Ray Fluorescence, and Fourier-transform infrared spectroscopy. The phytochemical constituent of the microalgae biofilm was also determined before and after treatment of the petroleum-contaminated water. The result obtained shows highest removal efficiency of physicochemical parameters (turbidity (81%), conductivity (51.2), sulfate (17.5%), alkalinity 28.4%), chloride (14.6%), TDS (7.9), TSS (26%), nitrate (33%), salinity (23.4), iron (16%), potassium (22%), phosphate (28.2%), chlorine (14%), chromium (13.6%), magnesium (30.3%), zinc (40.5%), COD (8%), BOD (16.7%) and total petroleum hydrocarbon (15%)). The microalgae's characterization shows microalgae biofilm's ability to adsorb pollutants in petroleum-contaminated water due to the presence of microspores and larger surface area of the cells of the microalgae forming the biofilm or due to the absorption efficiency of the extracellular polymeric substances (EPS). The analysis of the microalgae biofilm's phytochemical parameters shows the involvement of the chemicals components in pollutants degradation and antioxidant response of the microalgae to counteract the oxidative effect resulting from the exposure of the microalgae to the contaminated water.

NOVELTY STATEMENT This is the first study that attempts the phycoremediation of petroleum contaminated water using microalgae biofilm. The reduction efficiency of the parameters treated in this study is very low compared to that reported in the literature but increases with the retention day. This low reduction efficiency is attributed to the slow assimilation of organic and inorganic pollutants due to the initial growth condition. This study is the first to re-affirm that microalgae biofilm can phycoremediate petroleum-contaminated water by adsorption and assimilation due to the presence of microspores and a larger surface area the cells of the microalgae forming the biofilm or the extracellular polymetric surface covering the biofilm. Several studies have reported that phytochemicals present in microalgae play an antioxidant response role to prevent the microalgae from oxidative damage resulting from water pollution. However, this study is the first to strongly link phytochemicals to the enhancement of pollutants degradation and adsorption by microalgae biofilm.

摘要

本研究旨在研究使用在富含营养的水中培养的微藻生物膜对石油污染水的藻类修复。微藻生物膜在含有富含硝酸钙、氯化锰、酒石酸钾钠、磷酸钙和硫酸铵的水的光生物反应器中生长。将石油污染的水倒入光生物反应器中，将含有微藻生物膜的基质插入光生物反应器中，并允许生物膜形成八周。理化参数（pH、浊度、电导率、硫酸盐、碱度、氯化物、TDS、TSS、硝酸盐、盐度、铁、钾、磷酸盐、氯、铬、镁、锌、COD、BOD和总石油烃（TPH）测定处理前后石油污染水。用于处理的微藻生物膜在处理前后使用扫描电子显微镜、X 射线荧光和傅里叶变换红外光谱进行表征。在处理石油污染的水之前和之后，还测定了微藻生物膜的植物化学成分。所得结果表明，理化参数（浊度（81%）、电导率（51.2）、硫酸盐（17.5%）、碱度28.4%）、氯化物（14.6%）、TDS（7.9）、TSS（26%）、硝酸盐 (33%)、盐度 (23.4)、铁 (16%)、钾 (22%)、磷酸盐 (28.2%)、氯 (14%)、铬 (13.6%)、镁 (30.3%)、锌 (40.5) %)、COD (8%)、BOD (16.7%) 和总石油烃 (15%)）。微藻的表征显示微藻生物膜' 由于微孢子的存在和形成生物膜的微藻细胞的更大表面积或由于细胞外聚合物 (EPS) 的吸收效率，它能够吸附石油污染水中的污染物。对微藻生物膜的植物化学参数的分析表明，化学成分参与污染物降解和微藻的抗氧化反应，以抵消微藻暴露于污染水所产生的氧化作用。

新颖性声明这是第一项尝试使用微藻生物膜对石油污染水进行藻类修复的研究。与文献报道的相比，本研究中处理的参数的降低效率非常低，但随着保留天数的增加而增加。这种低还原效率归因于初始生长条件下有机和无机污染物的缓慢同化。这项研究首次重申，微藻生物膜可以通过吸附和同化对石油污染的水进行藻类介导，因为微孢子的存在以及形成生物膜的微藻细胞或覆盖生物膜的细胞外聚合物表面的表面积更大。多项研究表明，微藻中存在的植物化学物质具有抗氧化反应作用，可防止微藻因水污染而受到氧化损伤。然而，这项研究首次将植物化学物质与微藻生物膜对污染物降解和吸附的增强联系起来。