Three-Stage Membrane Treatment of Wastewater from Biodiesel Production-Preliminary Research

As biodiesel production as renewable fuel increases, so does the amount of wastewater resulting from this technology. Wastewater is generated during the so-called biodiesel washing, i.e., washing out glycerol and methanol with water. The purified biodiesel must meet international standards, such as EN 14214 or the American ASTM D6751 standard. To fully say that biodiesel technology is environmentally friendly, the amount of wastewater should be minimized. It is also desirable that the purified water can be recycled to the technology. For this purpose, wastewater pre-treated by flotation, during which mainly oils are removed, was subjected to three-stage membrane separation. For each of the stages, the membrane was selected and characterized in terms of its separation capacity and stream stability. Starting with microfiltration, which was mainly aimed at reducing turbidity, affects the permeate flux in the following steps. Then, ultrafiltration and nanofiltration membranes were selected. These membranes were aimed at reducing the concentration of inorganic and organic substances. Consequently the cascade was composed of: MF-0.45 µm, UF-150 kDa, and NF-characterized by an 80% degree of desalination. The final permeate has a salt concentration of less than 0.15 g/L and can be reused in biodiesel technology.

A study of inline chemical coagulation/precipitation-ceramic microfiltration and nanofiltration for reverse osmosis concentrate minimization and reuse in the textile industry

Reverse osmosis concentrate (ROC) is one of the major drawbacks in membrane treatment technologies specifically due to the scale-forming ions. It is important to remove these ions from ROC to enhance total water recovery and reuse in the textile industry that is the largest water-consumer and polluter industry. In this work, coagulation/high pH precipitation (CP) integrated with ceramic microfiltration (CMF) was studied as a pretreatment method followed by nanofiltration (NF) to increase the efficiency of water recovery. To prevent organic fouling, ferric chloride (FeCl3) was applied at a concentration of 3 mM, and ceramic membranes were used for the removal of non-precipitating crystals and/or suspended solids (at high pH) before the NF processes. The CP-CMF method successfully removed calcium (Ca2+), magnesium (Mg2+), silica (SiO2), and TOC up to 97, 83, 92, and 87% respectively, which resulted in higher performance of the NF process. Moreover, this method provided higher flux at lower pressure that ultimately increased overall water recovery of the NF process to achieve near-zero liquid discharge (n-ZLD). A cost-benefit estimation showed that a high-quality effluent (COD<5 mg/L; conductivity 700<μS/cm; negligible residual color) can be generated and recycled in the textile industry at an economical cost (approximately 0.97 USD/m3). Therefore, ROC minimization and water recovery can help to achieve n-ZLD using CP-CMF/NF method.

Life cycle design and efficiency strategy for sustainable membrane technology

Life Cycle Assessment (LCA) is an assessment tool to evaluate the potential environmental impact of a system or product throughout its life cycle. Results from LCA provides an insight on developing a more sustainable system while identifying its environmental hotspots. With recent advancements in membrane treatment systems especially for wastewater treatment (WWT), there is a rising interest in its sustainability aspect. Thus, it is crucial to review on previous published studies to highlight the challenges and achievements in implementing LCA for the membrane system. Hence, this paper presents a review of 33 recent papers published from year 2017-2020 conducting LCA on membrane systems for WWT. Bounded by the key frameworks of ISO standards, the analysis of papers showed variance in defining its functional unit, system boundaries, impact assessment categories and method to evaluate LCA, which makes it a challenge to do comparison. Some of the challenges discussed and highlighted in this paper include the inconsistencies in specifying the impact assessment and methodology used for some journals and the lack of LCA study in certain regional areas. A more uniform implementation of LCA should be considered to ensure the reliability and reproducibility of results to allow adoptions on novel or existing membrane systems.

Contemporary Techniques for Remediating Endocrine-Disrupting Compounds in Various Water Sources: Advances in Treatment Methods and Their Limitations

Over the years, the persistent occurrence of superfluous endocrine-disrupting compounds (EDCs) (sub µg L−1) in water has led to serious health disorders in human and aquatic lives, as well as undermined the water quality. At present, there are no generally accepted regulatory discharge limits for the EDCs to avert their possible negative impacts. Moreover, the conventional treatment processes have reportedly failed to remove the persistent EDC pollutants, and this has led researchers to develop alternative treatment methods. Comprehensive information on the recent advances in the existing novel treatment processes and their peculiar limitations is still lacking. In this regard, the various treatment methods for the removal of EDCs are critically studied and reported in this paper. Initially, the occurrences of the EDCs and their attributed effects on humans, aquatic life, and wildlife are systematically reviewed, as well as the applied treatments. The most noticeable advances in the treatment methods include adsorption, catalytic degradation, ozonation, membrane separation, and advanced oxidation processes (AOP), as well as hybrid processes. The recent advances in the treatment technologies available for the elimination of EDCs from various water resources alongside with their associated drawbacks are discussed critically. Besides, the application of hybrid adsorption–membrane treatment using several novel nano-precursors is carefully reviewed. The operating factors influencing the EDCs’ remediations via adsorption is also briefly examined. Interestingly, research findings have indicated that some of the contemporary techniques could achieve more than 99% EDCs removal.

Determining the influence of membrane treatment process on the quality indicators of beer

The issue related to the possibility of applying the filtration process of young beer with the use of experimental microfiltration polymer semi-permeable membrane elements was considered. It was shown that under modern conditions, it is expedient to use membrane processes of young beer filtration in the brewing industry. The process of membrane treatment of beer can be carried out at the stage of pasteurization of young beer in a cold way. Such actions can be directed to preserve the organoleptic parameters of the final product ‒ filtered beer. An experimental setup for the study of the main technological parameters of membrane processing of young beer was presented. The results of experimental studies of the influence of baric and temperature modes on the performance of nuclear microfiltration polymer membranes were shown. Rational parameters of pressure (0.03–0.05 MPa), duration (8–10 s-1), and temperature (3...6 °С) of the process of membrane filtration of young beer using nuclear microfiltration polymer membranes were determined. The qualitative characteristics of filtered beer obtained by membrane methods were explored. The comparative characteristic of the results of the studies of the qualitative component of resulting beer after microfiltration according to the known requirements and standards for organoleptic indicators was presented. It is found that in terms of filtration rate, selectivity, yeast residue, and other characteristics, nuclear microfiltration polymer membranes are promising for the implementation of the process of microfiltration of young beer. These studies proved the feasibility of further research into improving the process of membrane processing of beer and technical equipment of the beer production line with the development of new equipment.

Preparation of Liposomes from Soy Lecithin Using Liquefied Dimethyl Ether

We investigated a method to prepare liposomes; soy lecithin was dissolved in liquefied dimethyl ether (DME) at 0.56 MPa, which was then injected into warm water. Liposomes can be successfully prepared at warm water temperatures above 45 °C. The transmission electron microscopy (TEM) images of the obtained liposomes, size distribution, ζ-potential measurements by dynamic light scattering and the amount of residual medium were compared by gas chromatography using the conventional medium, diethyl ether. The size of the obtained liposomes was approximately 60–300 nm and the ζ-potential was approximately −57 mV, which was almost the same as that of the conventional medium. Additionally, for the conventional media, a large amount remained in the liposome dispersion even after removal by depressurization and dialysis membrane treatment; however, liquefied DME, owing to its considerably low boiling point, was completely removed by depressurization. Liquefied DME is a very attractive medium for the preparation of liposomes because it does not have the toxicity and residue problems of conventional solvents or the hazards of ethanol addition and high pressure of supercritical carbon dioxide; it is also environmentally friendly.

A Review Of Reverse Osmosis Membrane Fouling: Formation and Control

Membrane application in reverse osmosis (RO) membrane is getting more attention especially in producing drinking water. However, RO membrane faces challenges that reduces its performance such as its permeation flux, salt rejection, additional energy demand, lifetime decrease, extra pre-treatment process, cleaning and maintenance. The challenge is the formation of fouling. RO membrane fouling can happen inside or outside the membrane and the characteristics of membrane fouling differs from one type to other types, depending on the nature and location of membrane fouling. There are several types of RO fouling, which are Biofouling, Organic Fouling, Inorganic Fouling and Colloidal Fouling. The causes of RO membrane are different from one to another. The properties and materials of the solution entering RO membrane are important as it affects the type of fouling of RO membrane fouling. All of the RO membrane foulings need to be considered during membrane usage and demand solution to be controlled. In order to control the fouling in Reverse Osmosis membrane, there have been several control solutions discovered to the membrane fouling challenges. The control solutions are specified to each one of the fouling, in spite of wide applications for some of it. The control solutions are pre-treatment, which has many methods such as photo oxidation, coagulation, scale inhibitor, ion exchange resins, granular media and membrane treatment, membrane monitoring, membrane cleaning, surface modification, and material addition to membrane or novel membrane material. With various control solutions discovered, the RO membrane still faces fouling issue and is still demanding some more advanced applicable control solutions.

Technological breakthrough of the agrarian-and-food innovations in dairy case for example of universal agricultural raw materials. Reverse osmosis

Aim. Consideration of the membrane technology process – reverse osmosis – by directed and controlled processing of whey and its filtrates through special semipermeable partitions (filter membranes) with a pore size from 0.1 to 1.0 nm, carried out at a pressure of 3.0 - 10.0 MPa with the release of particles (cutting off) with a molecular weight of 100 Daltons. Reverse osmosis allows you to concentrate all the compounds of whey and filtrates, separating almost distilled water (condensate). Discussion. In the molecular sieve separation system, reverse osmosis logically continues the membrane treatment of filtrates (permeates) of native, as well as separated whey and their microfiltrates, ultrafiltrates, nanofiltrates and diafiltrates. In principle, the reverse osmosis process should be implemented to pre-concentrate the whey, which will eliminate its loss (draining) and expand the range of use. OO is promising for processing salted whey with the removal of unwanted sodium chloride, as well as for cleaning the condensate of evaporation plants from the components of dairy raw materials that come with foam and secondary steam. Conclusion. In general, for the dairy industry of the food industry of the agro-industrial complex, reverse osmotic treatment is necessary for the implementation of a closed production cycle with a recycled water supply.