Microfiltration

Günümüzde Türkiye`de bölgesel içme ve kullanma suyu sıkıntısı yaşanmaktadır. Türkiye’de yağış miktarı bölgeden bölgeye farklılık göstermektedir.  Baraj, göl, akarsular gibi yüzeysel su kaynakları bulunmayan veya yetersiz olan bu bölgelerde, alternatif çözümlere yönelmek gerekmektedir.  Söz konusu alternatifler arasında en kalıcı ve ekonomik çözüm, mevcut kaynaklara yönelip, yüzey suyunu arıtarak içme ve kullanma suyu temin etmektir.

Her geçen gün üretimi ve kullanımı artan ters osmoz sistemlerin kapsamlı olarak yapılacak bir maliyet analizi, sistemlerin tasarım ve seçiminde ekonomik açıdan faydalı bilgiler sağlayacaktır. Dolayısıyla bu çalışmanın amacı, yüzey sularından ultrafiltrasyon ve ters osmoz membranları ile su temin edilmesi durumunda, membran sistemlerinin maliyet analizinin ve tasarımının yapılmasıdır.

The ing and integration water ultrafiltration treatment construction of low-pressure (UF) facilities membranes has been and microfiltration new into water both treatexist(MF) and ultrafiltration (UF) membranes into both existing water treatment facilities and new water treatment plant construction has been rapidly gaining favor worldwide (AWWA, 2005). Contributing factors include the efficacy of these membranes in removing cysts and their consistent ability to produce low-turbidity product water despite variations in source water quality. One example of a decision to incorporate MF/UF technology into existing water treatment facilities is in Minnesota, where the Minneapolis Water Works has replaced aging granular media filters with UF at its 70mgd (265-ML/d) Columbia Heights Filtration Plant. Another example is in California, where the Modesto Irrigation District is doubling capacity from 36 to 72 mgd (136 to 273 ML/d) by adding membranes in parallel with existing granular media fil...

Heat treatments are the established food technology for commercial processing of milk. However, degradation of valuable nutrients in milk (as proteins) and its sensory characteristics occur during these processes due to substantial heat exposure. The most important reactions that occur during milk heat treatment are the whey proteins denaturation, its interactions with the casein micelles and aggregation/dissociation of the casein micelles. Microfiltration represents an emerging food processing technology allowing gentle milk preservation at lower temperatures for similar, or better, nutritive value, microbial removal, and shelf stability. Thus, the aim of this work is to review the existing studies on the effects of microfiltration on milk proteins by comparing with the effects of heating treatments.

Membrane separation technology offers a potential application in the processing of crude palm oil. Ceramic membranes with different pore diameters (0.45 and 0.2 micron) were used to conduct the study on micromembrane process. Quality parameters of membrane-processed oils examined included free fatty acid (FFA), carotene, fatty acid composition (FAC), phosphorus and iron contents. The effect of operating parameters such as transmembrane pressure, feed flow and time on permeate flux were evaluated. It was found that ‘Ceraflo’ceramic membrane with a pore size of 0.45 micron was only able to reject 14% of phosphorus from the crude oil. Ceramic membrane with pore size of 0.2 micron showed a better phosphorus rejection of 56.8%. The permeate was found to contain 7.13 ppm of phosphorus. The 0.2 micron membrane was also able to remove more than 80% of the iron from crude palm oil. Pore sizes for both membranes were not small enough to remove other components such as FFA, and carotene. Both membranes showed a similar trend in which the permeate flux increased with transmembrane pressure and feed flow until a certain limit where the flux declined with increasing pressure and feed flow. The limits in transmembrane pressures for membrane with pore sizes of 0.45 and 0.2 micron were 1.65 and 1.25 bar, respectively. Whereas the limits in feed flow for 0.45 micron and 0.2 micron membranes were 9.2 and 9.8 L/min

Hollow fiber membrane modules have had many applications, such as filtration, extraction, and oxy- genation, in numerous industrial processes for many years. As bioreactors, they are extensively used for enzyme reactions and cell/bacteria/yeast culture. The concept of a hollow fiber membrane bioreactor (HFMB) used in cell culture is shown in Figure 1.
The hollow fiber membranes are contained in an external shell (normally in the shape of a cylinder). The cells can be attached to the outer surface of the membranes, or more commonly maintained in the extracapillary space (ECS). Nutrients flow in the lumen of the fibers and can diffuse out through the pores of the fiber wall to feed the cells. Also, the metabolic waste produced by cells can permeate back into the fibers and be carried away.
HFMBs have been used to culture a variety of mammalian cell lines since their inception by Knazek [1]. HFMBs for mammalian cell cultures are mainly used to produce expensive biochemicals such as vac- cines [2], interferons [3], hormones [4], growth factors [5], viruses [6], and monoclonal antibodies [7] and to act as artificial organs [8, 9].
There are many advantages which HFMBs offer over other culture methods. HFMBs have high sur- face-to-volume ratios of around 30 cm2/cm􏰀3 [10], thus giving the potential to grow cells to high densities.
The continuous supply of uniform liquid and gaseous nutrients and removal of metabolic wastes provide a stable microenvironment for cells. The selective perme- ability property can protect cell culture from the immune system in artificial organ applications and to facilitate the recovery in biological product manufacture [11]. Cells are subject to low shear forces due to their separation from the nutrient flow in the fiber lumen.
More recently, HFMB found its application in the area of regenerative medicine. Generally speaking, regenerative medicine includes either engineered functional tissues or therapeutic quantities of cells. Tissue engineering applications aim at developing functional tissues from cells in combination with a suitable matrix to support and accelerate regenera- tive healing, while cell therapy only transplants required type and amount of cells into the defect site. This chapter presents a summary on the appli- cation of HFMBs in regenerative medicine, as an enabling technology to support three-dimensional (3D) tissue culture and to expand stem cells.