Submerged membrane bioreactor for waste water treatment: determination of the shear stresses produced by coarse bubbles

Submerged membrane bioreactor for waste water treatment: determination of the shear stresses produced by coarse bubble

Zeolite-filled silicone rubber membranes : Part 1. Membrane preparation and pervaporation results

Amongst the alternative fuels obtained from renewable resources alcohol from fermentation may become one of the most important. The combination of fermentation with pervaporation in a membrane bioreactor offers the advantage of continuous processing. In this membrane bioreactor alcohol-selective membranes are needed. The performance of the membranes available at present is poor. Much research is being carried out on silicone rubber but the selectivity of this material for alcohol is too low. Addition to the membrane of a sorptive filler with a high selectivity towards alcohol appears to improve both selectivity and flux. Silicalite, a novel type of hydrophobic zeolite, has been used for that purpose. Results presented in this paper indicate that transport through the zeolite pores contributes to a major extent to the total transport through the membrane

Aeration mode, shear stress and sludge rheology in a submerged membrane bioreactor: some keys of energy saving

Aeration mode, shear stress and sludge rheology in a submerged membrane bioreactor: some keys of energy savin

Anaerobic membrane bioreactors: Are membranes really necessary?

Membranes themselves represent a significant cost for the full scale application of anaerobic membrane bioreactors (AnMBR). The possibility of operating an AnMBR with a self-forming dynamic membrane generated by the substances present in the reactor liquor would translate into an important saving. A self-forming dynamic membrane only requires a support material over which a cake layer is formed, which determines the rejection properties of the system. The present research studies the application of self-forming dynamic membranes in AnMBRs. An AnMBR was operated under thermophilic and mesophilic conditions, using woven and non woven materials as support for the dynamic membranes. Results showed that the formation of a cake layer over the support materials enables the retention of more than 99% of the solids present in the reactor. However, only low levels of flux were achieved, up to 3 L/m2 x h, and reactor operation was unstable, with sudden increases in filtration resistance, due to excessive cake layer formation. Further fine-tuning of the proposed technology involves looking for conditions that can control effectively cake layer formatio

A review on the present situation of wastewater treatment in textile industry with membrane bioreactor and moving bed biofilm reactor

Membrane bioreactor (MBR) is one of the advanced treatment technologies used in industrial wastewater treatment due to its various advantages over conventional biological processes. Recently, the application of MBR in treatment of textile wastewater has increased significantly with an effective removal of contaminants. Moving bed bioreactor (MBBR) has been efficiently used for the treatment of different municipal and industrial wastewater during the last decades and it is a relatively novel and effective technology applied in textile wastewater treatment. This review paper presents the situation of MBR and MBBR technology for textile wastewater purification under different conditions and collates results of previous studies during the past years about MBR and MBBR treatment technologies used in textile processes. Both of these two technologies have shown their efficiency, but they still have problems in textile wastewater treatment. To this end, MBR-MBBR hybrid system could be an attractive solution for textile wastewater purification because of the high efficiency and low consumption of energy and spacePostprint (author's final draft

Modelling of submerged membrane bioreactor: Conceptual study about link between activated slugde biokinetics, aeration and fouling process

A mathematical model was developed to simulate filtration process and aeration influence on Submerged Membrane Bioreactor (SMBR) in aerobic conditions. The biological kinetics and the dynamic effect of the sludge attachment and detachment from the membrane, in relation to the filtration and a strong intermittent aeration, were included in the model. The model was established considering soluble microbial products (SMP) formation-degradation. The fouling components responsible of pore clogging, sludge cake growth, and temporal sludge film coverage were considered during calculation of the total membrane fouling resistance. The influence of SMP, trans-membrane pressure, and mixed liquor suspended solids on specific filtration resistance of the sludge cake was also included. With this model, the membrane fouling under different SMBR operational conditions can be simulated. The influence of a larger number of very important process variables on fouling development can be well quantified. The model was developed for evaluating the influence on fouling control of an intermittent aeration of bubbles synchronized or not with the filtration cycles, taking into account the effects of shear intensity on sludge cake removal

Role and variations of supernatant compounds in submerged membrane bioreactor fouling

Many studies have been performed to analyze the influence of extracellular polymeric substances (EPS) in membrane fouling. Most of these works deal with the impact of solid contents in the fouling, and some of them have studied the role ofsupematant compounds. The aim of this work was to clarify the role of the different sludge fractions in the context of membrane bioreactor fouling. The laboratory-scale reactor used for experiments consists of a submerged membrane bioreactor for the treatment of synthetic wastewater. For the same organic load (0.4 g COD/g MLSS.d), several samples of sludge were taken off and divided intohree fractions (solid contents, soluble and colloids). COD and extractable EPS were quantified (carbohydrates and proteins). Dead-end filtration tests for each fraction were also carried out. According to these experiments, no correlation between EPS concentration in the solid part of the sludge and filtration resistance was found. Instead, a change of the filtration resistance was explained as a function of COD in the supematant, and more especially as a function of proteins concentration. Indeed, when the value of proteins concentration in the supernatant changes from 30 to 100 mg/1, the value of specific resistance increased by a factor of 10. Finally, the characterization of the supematant was shown as a key parameter for the MBR operating control. When the COD and proteins concentration in the supematant remained low, the transmembrane pressure in the reactor remained even lower. Moreover, with the biomass growth rate analysis, our results suggest that the EPS production was linked to growth of microorganisms. The faster he growth, the less EPS production

Dynamical Modelling and Simulation of Waste water Filtration Process by Submerged Membrane Bioreactors

A mathematical model was developed for the filtration process and the influence of aeration on Submerged Membrane Bioreactors. The dynamics of sludge attachment to and detachment from the membrane, in relation to the filtration and a strong intermittent aeration, were included in the model. The influence on the membrane fouling of intermittent aeration injected on the membrane surface, and its synchronization with intermittent filtration, were studied numerically and experimentally. For the evaluation of filtration cake development, the assumption of the presence of two cake layers (one dynamic and the other stable) was considered. The model development and simulation focused on the description of existing relationships among important system variables like mixed liquor suspended solids concentration, aeration, temperature of the sludge suspension, transmembrane pressure, and the fouling increase during the filtration process. The model obtained offers the possibility of improving the design configuration and operation strategies of Submerged Membrane Bioreactors in wastewater treatment, and it allows the of aeration-filtration cycles to be optimized

Improvement of the total mass and operating time of Knapsack sprayer to Propel Cart Sprayer (PCS)

There are two types of background of the farmers which are the large scale and small scale of agriculture. Usually, the large scale farmers will use the motorize Knapsack Sprayer while the small scale farmers will use manual-operated Knapsack Sprayer. The motorize Knapsack Sprayer that uses by the large scale of agriculture farmers’ area is to save the cost and time [1]. Unfortunately, both types of Knapsack Sprayer have their own ineffectiveness and risk especially the manual Knapsack Sprayer. The farmers that use the manual Knapsack Sprayer will have to carry the heavy load at their back while spraying the pesticide. These are a very burden to the farmers, especially for the old farmers. The weight of the mixture carried can be up to 17 kilograms depends on the density of the mixture whereas the safe weight lifting legalize by OSHA is 22.68 kilograms which the load almost near to its limit for average man and will affect the body locomotion and bones structure is carried in a long term period [2]. The total sprayed area per full tank is 44.09 meters square. The process of spraying the pesticide will slow down because the farmers have to bring the heavy load