Search

Recently, resource recovery has gained importance due to increased population and rapid industrialization. In this study, the use of composite diluted draw solution (DDS) of anaerobic microfiltration osmotic membrane bioreactor (AnMF-OMBR), and up-flow anaerobic sludge blanket microfiltration osmotic membrane bioreactor (UASB MF-OMBR) treated synthetic slaughterhouse wastewater as liquid fertilizer was evaluated. The DDS was diluted with tap water to provide agricultural irrigation water due to its high salinity. The suitability of agricultural irrigation was evaluated according to agricultural irrigation standards (MEU, 2010). Liquid fertilizer applications were carried out in a plastic-coated wooden flower pots at room temperature. Grass seed planted in a 26-section pot were irrigated with DDSs of both reactors and commercial fertilizers (nitrogen, phosphorus, and potassium fertilizers). At the end of the study; root length, grass height, the number of shoots, the number of fringes, grass color, plant water holding capacity, soil water holding capacity and coating rate were determined. The data were evaluated with the Analytical Hierarchy Process (AHP). It was observed that the grass irrigated with DDS of UASB MF-OMBR more improved than the grass irrigated with DDS of AnMF-OMBR in terms of the number of fringe, grass color, and coating rate. Furthermore, the grass irrigated with composite DDSs grew more than the grass irrigated with commercial fertilizers. This study showed that the DDSs of both reactors could be used as liquid fertilizer. [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) is a membrane process for wastewater treatment and resource recovery with significant advantages such as high rejection of contaminants and low energy requirement. However, membrane fouling is a major issue for the application of the FO process in these applications. This study aims to determine the effect of the draw solution (DS) on membrane fouling in batch FO processes treating slaughterhouse wastewater. 6-hour batch FO studies were carried out using MgCl2 as the draw solution (DS) in different concentrations (0.47, 0.75, 1, 1.5, 2 M), and the synthetic slaughterhouse wastewater as the feed solution (FS). A cellulose triacetate (CTA) membrane was used as FO membrane. Membrane autopsy studies containing scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FT-IR), and contact angle were performed on clean and fouled FO membranes after the batch FO studies with MgCl2. The SEM analysis demonstrated that there were precipitates on the membrane surface, but the helical structure of the membrane was not disturbed and fouling occurred in the membrane pores and surface. The data obtained from EDX analysis revealed an increase in the percentages of Mg and Cl (wt%) with increasing DS concentrations. In the FT-IR analysis, it was determined that the increase in DS concentrations did not cause a significant change in the membrane structure, and did not have sufficient effect to change the FT-IR spectra. The contact angle studies on the fouled FO membranes showed that the contact angle value increased with increasing DS concentrations, and thus the membrane became more hydrophobic. As a result of the AFM analysis, salt accumulation was observed on the membrane surface, and the Rrms value increased with increasing DS concentrations together with the rougher surface structure. [ABSTRACT FROM AUTHOR]

Anaerobic microfiltration osmotic membrane bioreactors (AnMF-OMBRs) have gained considerable importance in recent years. The AnMF-OMBR has been developed to prevent salt accumulation by adding a microfiltration (MF) membrane into the anaerobic osmotic membrane bioreactor (AnOMBR). Despite this modification, the AnMF-OMBR still has issues such as microbial inhibition caused by high salinity and membrane fouling. Up-flow anaerobic sludge blanket microfiltration osmotic membrane bioreactor (UASB MF-OMBR) systems have been revealed to avoid these issues. In this paper, laboratory scale AnMF-OMBR and UASB MF-OMBR systems treating slaughterhouse wastewater were operated using MgCl2 as draw solution (DS) in different salt concentrations (0.47, 1, and 1.5 M). The effects of DS concentration on forward osmosis (FO) membrane fouling were investigated for both systems. Membrane autopsy analyses were performed for the fouled FO membranes that used at different DS concentrations. Atomic force microscopy (AFM), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), fourier-transform infrared spectroscopy (FTIR), and confocal laser scanning microscopy (CLSM) measurements were carried out for fouling characterization. The AFM results indicated that fouling on the membrane surface increased with increasing DS concentration for both systems. Also, the CLSM indicated that the thickness of the biofouling layer on the FO membranes belonging to both reactors aggravated when the DS concentration increased. Furthermore, the FO membrane of UASB MF-OMBR had less biofilm layer and the design of the reactor can effectively prevent the biofoulants deposition on the membrane surfaces. The FTIR spectra showed new absorption peaks related to protein substances on the fouled FO membranes of both reactors. As a result, compared with the AnMF-OMBR, the FO membrane in the UASB MF-OMBR had less fouling due to the novel reactor configuration. [ABSTRACT FROM AUTHOR]