Crossflow Configuration

In cross-flow filtration, the wastewater flow is parallel to the membrane (Fig. 12.8c). There is a continuous retentate stream in addition to the feed and permeate stream and a three-end module is necessary. The retained material builds a layer on the surface of the membrane which can be influenced by the cross-flow rate. Thus the process is in continuous operation (see Table 12.5). The reversible gel layer can be controlled by cross-flow conditions, while an irreversible gel layer has to be...

Membrane Bioreactors in Aerobic Wastewater Treatment

The combination of biological and membrane filtration processes is known as a membrane bioreactor (MBR) system. The benefits of MBR systems in submerged or external cross-flow mode are (ATV-DVWK, 2000b DWA 2005) High microbiological quality of effluent water resulting from the high removal efficiency of suspended solids, microorganisms and viruses. Greater freedom to vary process parameters, like the reduction of excess sludge or the concentration of slowly growing organisms because MBR systems...

Aerobic Wastewater Treatment in Activated Sludge Systems 119

6.2 Kinetic and Reaction Engineering Models With and Without Oxygen Limitation 119 6.2.1.1 With High Initial Concentration of Bacteria 119 6.2.1.2 With Low Initial Concentration of Bacteria 122 6.2.3 Completely Mixed Activated Sludge Reactor 125 6.2.3.1 Preliminary Remarks 125 6.2.3.2 Mean Retention Time, Recycle Ratio and Thickening Ratio as Process Parameters 126 6.2.3.3 Sludge Age as Parameter 128 6.2.5 Completely Mixed Tank Cascades With Sludge Recycle 132 6.2.6 Flow Reactor With Axial...

QgcO20 cO2

After measuring cO2 in the exhaust gas. The change in the dissolved oxygen concentration is very low compared with the respiration rate because of the high Henry coefficient H, which is defined by Henry's law, see Eq. (5.6) where c is the O2 concentration in the gas and c 2 is the O2 concentration at the border gas liquid at equilibrium. In comparison to rO2_z, rCO2,z is more difficult to measure for two reasons The solubility of CO2 in water is much higher than that of O2. The soluted CO2L...

Membrane Characteristics and Definitions

Membranes are flat, semi-permeable structures that are permeable for at least one component and are impermeable for others. According to the nomenclature of membrane technology, various membrane processes are characterized according to the molar mass or diameter of the transported component, the aggregate state on the two sides of the membrane as well as the separation principle. The transport can be caused by gradients of concentration or pressure. Pressure-driven membrane processes like...

Water Supply and Wastewater Management in the Medieval

Different Parts Medieval Monastery

Monasteries founded by Cistercians, Premonstratensians and Benedictines in Europe during the 12th and 13th centuries were exemplary business undertakings for that time. Besides the monks and the abbot, numerous lay persons worked and prayed there, all requiring a reliable source of water. Frequently, a monastery was placed near a river and a ditch was dug, which was laid with a necessary gradient through the area of the monastery. Figure 1.4 presents a system for water supply and wastewater...

Water Supply and Wastewater Management in Antiquity

Management Antiquity Images

One of the most ancient systems of wastewater management was constructed in Mohenjo-Daro near the river Indus (Pakistan) at about 1500 BC. Some centuries later, the river moved its course and obviously the town was given up and covered by sand during the following decades. In the 1930s and 1940s, this early high civilization was newly discovered. Private and public houses were equipped with toilets. Water used for washing and bathing as well as rain water flowed through special grooves into...

The Concentration Mass Flow Rate Diagram and the Graphical Solution

In a water-using mass transfer process, different components are transported to the water (Fig. 13.7a). In the following, we will study only one component. The index i for different compounds can now be omitted. Fig. 13.7 Concentration mass flow rate diagram. (a) Schematic of a water using process for impurity. (b) A water-using process in a concentration mass flow rate diagram, with the water profile not limited for one impurity. (c) The water profile is limited (one impurity). 13.2 Production...

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Organic Nitrogen Wastewater

The Nitrogen Cycle and the Technical Removal Process The relationship between the various nitrogen compounds and their transformation is presented in Fig. 10.2 as the nitrogen cycle. The transformation reactions include fixation, ammonifi cation, assimilation, nitrification and denitrification. The principle compounds in the nitrogen cycle are nitrogen gas, ammonium, organic nitrogen and nitrate (De Renzo 1978). The atmosphere serves as a reservoir of N2 gas which is naturally transformed by...