Suspended Solid, Color, COD and Oil and Grease Removal from Biodiesel Wastewater by Coagulation and Flocculation Processes

Abstract

Coagulation and flocculation are essential processes in a number of diverse disciplines, including biochemistry, cheese manufacturing, rubber manufacturing, and in water and waste water treatment. Coagulation-flocculation is effective for removing high concentration organic pollutants and heavy metals in water and wastewater. However, limited information exists on the efficiency of this coagulation-flocculation process for biodiesel wastewater treatment. The biodiesel wastewater is basic (alkaline), with a high content of oil and grease, and a low content of nitrogen and phosphorus. As such, biological treatment of the biodiesel wastewater is expected to be very difficult. For this reason supportive physic-chemical methods are often used. Although one of the most frequently employed method is coagulation. Therefore, this study was conducted to investigate the efficiency of coagulation and flocculation processes for removing suspended solid (SS), color, COD and oil and grease from biodiesel wastewater. Aluminum sulfate, polyaluminum chloride, ferric chloride and ferric sulfate as a coagulant in biodiesel wastewater treatment were studied using a standard jar test apparatus. The result shows that, at the optimum dose of PAC (300 mg/L), the percentage removal of SS, color, COD and oil and grease respectively 97%, 95%, 75% and 97% compared to only 92%, 92%, 53% and 99% at the optimal dose alum (500mg/L), 95%, 93%, 63% and 97% at the optimum dose of ferric chloride (350 mg/L) and 88%, 88%, 54% and 94% at the optimum dose of ferric sulfate (450 mg/L). The effect of coagulant dosages on suspended solid (SS), color, COD and oil and grease removal showed similar trend and PAC was found to be superior was observed at reasonable lower amount of coagulant i.e. 300 mg/L. The results showed that coagulation-flocculation is effective as a pre-treatment for treating biodiesel wastewater.

Polymeric polyelectrolytes obtained from renewable sources for biodiesel wastewater treatment by dual-flocculation

“…Although membrane bioreactor was effective in treating biodiesel wastewater, a more soluble microbial product during biological treatment could lead to increases in the particle size with irregular shape, resulting in severe membrane fouling [8]. Therefore, physical-chemical methods are often proposed [9]. Typically, coagulation-flocculation process is regarded as one of the most important treatment processes of industrial wastewater [10] and raw water [11] due to its simplicity, effectiveness and low energy consumption.…”

“…In addition to the structural-mechanical factor and the electrostatic factor of aggregation stability, these chemical characteristics of the cellulose acetate sulfate allowed to recommend them for effective preparations for the contaminated water purification. In the literature there are many studies regarding the biodiesel wastewater treatment by coagulation-flocculation [9], adsorption [36], flotation by dissolved air [37], electro-coagulation [38,39], electro-oxidation [40]. However, there are no reports of biodiesel wastewaters treatment by flocculation using only natural flocculants.…”

Effects of a polymeric organic coagulant for industrial mineral oil wastewater treatment using response surface methodology (RSM)

“…The selection of the right type of polymeric coagulant for application depends on its sensitivity and operating conditions, applied in the right proportion to initiate neutralization, stability and mobility of the colloidal oil droplets in order to enhance treatment effectiveness (Hosny et al, 2016). The removal of the targeted contaminants in the MOW, the type of coagulant, coagulant dosage, pH and flotation time also play an important role to enhance the treatability and efficiency (Zouboulis and Avranas, 2000;Daud et al, 2015). Therefore, the Box-Behnken design (BBD) of experiment was adapted from the response surface methodology (RSM) to optimise the relevant operating parameters in order to reduce the researcher's experimental workload and high cost of chemical usage, and to avoid uncertainty on industrial application (Chavalparit and Ongwandee, 2009;Li et al, 2016;Tetteh and Rathilal, 2017).…”

“…However, coagulation flotation is a complicated process, which involves a series of physical-chemical interactions for the removal of contaminants, depending on the type of coagulant (Diya'uddeen et al, 2011;Daud et al, 2015). Coagulation, which is usually the first stage in a pre-treatment process, neutralises the charge of the oil droplets and forces them to agglomerate.…”

Tratamiento de efluentes acuosos provenientes de la industria de biodiesel, utilizando tecnología de membranas

“…Algunos autores han estudiado el tratamiento de este tipo de efluentes mediante: tratamiento biológico [4,6], coagulación y/o electrocoagulación [7][8][9][10] y adsorción [11,12]. Este último método casi no ha sido utilizado para el tratamiento de aguas residuales de biodiesel.…”