Management of fatty acid methyl ester (fame) wastewater by a combined two stage chemical recovery and coagulation process

Abstract

A two-step treatment process for fatty acid methyl ester (FAME) wastewater was carried out at a laboratory scale and ambient temperature. In the first step, FAME was chemically recovered from the wastewater using three types of acid (H 2 SO 4 , HNO 3 , and HCl) at different pH values ranging from 1.0 to 8.0. Optimally, approximately 15-30 mL/L of FAME was recovered when using H 2 SO 4 at a final wastewater pH of 1-2.5 and a reaction time of 7 min. The properties of the recovered FAME were within the acceptable ranges for both community and methyl ester standards, except for the viscosity and the quantity of methyl ester. In the second treatment step, the aqueous phase discharged from the first step was adjusted to within the favourable pH range for chemical coagulation by either Al 2 (SO 4 ) 3 (pH 4.5-10) or poly-aluminum chloride (PAC; pH 2.5-7.0) by the addition of CaO, and then subjected to chemical coagulation with either Al 2 (SO 4 ) 3 or PAC, as appropriate dose at 0-10 g/L. Under optimum conditions, >98.3%, 97.7%, and 99.2% of COD, BOD 5 , and oil and grease were respectively removed using Al 2 (SO 4 ) 3 at 2 g/L, whilst that achieved by PAC coagulation (at 1 g/L) was slightly lower at 98.2%, 96.5%, and 98.6%, respectively. The calculated operating cost of this management system was significantly cheaper than those using conventional management procedures, but will require an additional treatment stage such as biological remediation in sedimentation ponds to reduce the pollutant levels to acceptable limits.On a procédéà un processus de traitement en deuxétapes pour l'eau résiduelle contenant de l'ester méthylique d'acide gras (EMAG)à l'échelle laboratoire età une température ambiante. Dans la premièreétape, l'EMAG aété retiré chimiquement de l'eau résiduelle par l'usage de trois types d'acides (H 2 SO 4 , HNO 3 et HCl)à différentes valeurs de pH allant de 1,0à 8,0. De façon optimale, environ 15à 30 ml/L d'EMAGétait récupéré lors de l'utilisation de H 2 SO 4à un pH d'eau résiduelle final de 1à 2,5 et un temps de réaction de 7 min. Les propriétés de l'EMAG récupéré se situaient dans lesécarts acceptables pour les normes communautaires et d'ester méthylique, sauf pour la viscosité et la quantité d'ester méthylique. Dans la deuxièmeétape de traitement, la phase aqueuse déversée lors de la premièreétape aété ajustée dans l'écart pH favorable pour la coagulation chimique soit par Al 2 (SO 4 ) 3 (pH 4,5à 10) ou chlorure de polyaluminium (CPA) (pH 2,5à 7,0) par l'ajout de CaO, puis soumiseà la coagulation chimique avec soit Al 2 (SO 4 ) 3 ou le CPA,à une dose appropriéeà 0à-10 g/L. Dans des conditions optimales, des quantités supérieuresà 98,3, 97,7 et 99,2% de DCO, DBO et d'huile et de graisse ontété respectivement retirées au moyen d'Al 2 (SO 4 ) 3à 2 g/L, alors que le retrait obtenu par la coagulation du CPA (à 1 g/L)était légèrement différentà 98,2, 96,5 et 98,6% respectivement. Le coût d'utilisation calculé de ce système de gestionétait considérablement plus bas que ceux qui utilisent des procédures de gestio...

Production of biodiesel and its wastewater treatment technologies: A review

“…Another factors being manipulated were alum dosage (0-6 g/L) and mixing rate (100-300 rpm). Kumjadpai et al (2011) carried out an investigation of treatment of wastewater from waste used oil biodiesel production plant using a two-step process involving chemical recovery using three types of acids (H 2 SO 4 , HNO 3 , and HCl) followed by a coagulation process using either Al 2 (SO 4 ) 3 (pH 4.5-10) or PAC (pH 2.5-7.0) by the addition of CaO. Optimally, through acidification using H 2 SO 4 at pH 1-2.5, approximately 15-30% fatty acid methyl esters (FAMEs) were recovered.…”

“…The individual treatments that have been reported include coagulation Kumjadpai et al, 2011), electrocoagulation (Srirangsan et al, 2009;), biological processes (Suehara et al, 2005), adsorption (Pitakpoolsil & Hunsom, 2013), and microbial fuel cell systems (Sukkasem et al, 2011).…”

Utilization of oil recovered from biodiesel wastewater as an alternative feedstock for biodiesel production

“…Further treatment prior to discharge into the environment is required. Thus, 1.46 USD/m 3 was added for the cost of chemical and biological treatment of BWW with a low pollutant load …”

Treatment of biodiesel wastewater by indirect electrooxidation: Effect of additives and process kinetics

“…Current biological processes are not capable of treating this biodiesel wastewater because its composition is unsuitable for microbial growth due to the presence of growth inhibitors [4]. Although a cheap two-step treatment process, comprised of chemical recovery by acid addition and then coagulation with Al 2 (SO 4 ) 3 or poly-aluminum chloride, can enhance the removal of BOD, COD and oil and grease levels to greater than 97%, their residual levels were still higher than the acceptable values for discharging into the environment due to the high initial content of contaminants in the biodiesel wastewater [5]. The coagulation-flocculation had high efficiency to pre-treat biodiesel wastewater [6].…”