Wastewater Treatment

Mention 5 Volutile Solute That Are Possibly Present In Waste Hard Water

Aao Waste Water

0.005 Mc5h7no2 0.005 -113 g mol-1 C5H7O2N Mno2-n 14 g mol-1 NO2-N The total yield values without accumulation of NO- for the growth of Nitrosomonas and Nitrobacter are 0.187 g MLVSS per g NH4-N oxidized or g NO3-N produced. Lindemann (2002) and Choi (2005) presented and compared some yield coefficients. Averaged values of YXA NH4-N and YXA NO2-N were calculated from values of different authors, as follows (Larsen-Vefring 1993) YXa nh4-n 0.142 g MLVSS (g NH4-N)-1 Yxa n02-n 0.02 to 0.084 0.048 g...

First Studies in Microbiology

Home Made Trip Wire With 209a Primers

Antoni van Leeuwenhoek (1632-1723) was the first person able to grind simple lenses and who built the first microscopes (Fig. 1.9). The biconvex lens (L) was fastened between two thin metal plates and the object was mounted up on the pin at (P), which was adjustable by moving two screws. He constructed many of these microscopes and all the necessary lenses he ground himself. The best of them magnified about 200 times (Burdon and Williams 1969). With these instruments, he patiently examined...

Submerged and Aerated Fixed Bed Reactors

Intermediate Reactors Area

In cases of high hydraulic loading, the trickling filter may be operated as a flooded bed and the pressure differential needed for the downwards flow increases. The level of wastewater necessary to overcome the flow resistance depends on the form of the substance used as support material and the thickness of the biofilm. Aerobic fixed beds must be aerated near the bottom, producing a two-phase flow in a three-phase system with an upwards air flow. As a result of friction forces, water is...

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...

Mean Retention Time Recycle Ratio and Thickening Ratio as Process Parameters

Retention Time Waste Water Treatment

Figure 6.3 presents the flow sheet of an activated sludge plant. The balance of bacteria X for the CSTR in steady state is 0 Qm(Xm- X) + (p - kd) X V (6.35) Corresponding to Eq. (6.35), the balance of substrate S is P with kd ks + ke as the decay coefficient. Fig. 6.3 Flow sheet for a completely mixed (stirred) activated sludge plant (CSTR). Fig. 6.3 Flow sheet for a completely mixed (stirred) activated sludge plant (CSTR). kd includes both the specific rate of death ks and that of mass...

Retention Time Distribution

Retention Time Waste Water Treatment

To understand and mathematically describe the activated sludge process in continuous operation, information is needed regarding the degree of mixing inside the reactor. Is the reactor completely mixed Are there short-circuit flows or regions of eddy currents What is the dispersion coefficient in a selected type of reactor Such questions can be answered by measurement and mathematical analysis of retention time distributions (Pippel 1978). Measurement of the distribution is realized by adding...

Chemical Oxygen Demand

Nitrogen Bases Different Species

The chemical oxygen demand (COD) is defined as the mass of oxygen needed for the complete oxidation of an organic compound present in water. For the oxidation of glucose (CH2O)6, a representative hydrocarbon, 1 mol O2 mol-1 C is needed according to (COH2)6 + 6 O2 6 CO2 + 6 H2O (2.2) For the standard COD test, a measured sample with a known excess of potassium dichromate (K2Cr2O7) is mixed after the addition of H2SO4 and silver sulfate (Ag2SO4). The organic matter is oxidized over a 2-h heating...

Methanogenic Bacteria

Methanospirillum Barkeri

Lower fatty acids such as butyrate and propionate can only be mineralized if two catabolic products of acetogenic bacteria, i.e. hydrogen and acetate, are consumed by methanogenic bacteria. The methanogens are very old microorganisms, living on earth since before the oxygen-rich atmosphere was formed. Methanosarcina and Methanothrix are able to grow using acetate for catabolism and 70 of the methane formed in digestion processes and elsewhere in nature is produced via Eq. (8.4) (Jeris and...

The Simple Plug Flow Model

Plug Flow Wastewater

The situation is described in Fig. 5.8 all bubbles rise with the same velocity w, which is not easy to measure. Therefore, the average void velocity is used with Ar as the cross-sectional area of the reactor (bubble column). We can balance the gaseous oxygen in the total volume of the bubble column and it is not necessary to determine the total gas volume, which would be nearly impossible in large open tanks. Fig. 5.8 Upward plug flow of water and flowing bubbles with corresponding diameters....

Membrane Characteristics and Definitions

Classification Membrane Filtration

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...

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...

Introduction

The high performance of membrane technology has been proven in recent years in a wide range of fields, such as chemical industry, medical technology, drinking water treatment, biotechnology and environmental technology. The German work groups of the DWA (ATV-DVWK 2000a, b, 2002a, b DWA 2005) have provided excellent reports on the application of membranes in the field of wastewater treatment. Also, the Chemical Engineering School at the RWTH Aachen has provided important knowledge of...

Rotating Disc Reactors

In rotating disc reactors (RDR), the principle behind the intense transport of substrates and oxygen to the biofilm is different. In trickling filters and fixed bed reactors, water and air are moved here, the support material with the biofilm are moved. In rotating disc reactors, circular plates with diameters of 1-2 m are fitted to a horizontal shaft with a spacing of a few centimeters. The system of parallel plates is submerged nearly halfway in a cylindrical tank through which wastewater...

Anaerobic Fixed Bed Reactor

Wastewater Fixed Bed Skid

A fixed bed reactor is filled with solid media to facilitate the formation of biofilms with anaerobic bacteria. Frequently, the synthetic media used are the same as those in trickling filters (Fig. 8.7a Young 1991) or, alternatively, they are porous polyurethane particles with a diameter between 0.3 cm and 1.0 cm and are used with inner surfaces for bacteria immobilization (Fig. 8.7b Spie 1991 Kus 1993). Examples of such support materials are shown in Fig. 8.7. The surface area for bacterial...

Historical Development of Wastewater Collection and Treatment

1.1 Water Supply and Wastewater Management in Antiquity 1 1.2 Water Supply and Wastewater Management in the Medieval Age 4 1.3 First Studies in Microbiology 7 1.4 Wastewater Management by Direct Discharge into Soil and Bodies of Water - The First Studies 11 1.5 Mineralization of Organics in Rivers, Soils or by Experiment -A Chemical or Biological Process 12 1.6 Early Biological Wastewater Treatment Processes 14 1.7 The Cholera Epidemics - Were They Caused by Bacteria Living in the Soil or Water...

Design and Configuration of Membrane Modules 12421 Preliminary Remarks

The following informations are valid generally for all possible applications. There are several very different ways to construct membrane modules by the arrangement of the inlet and outlet streams. For example, a three-end module for cross-flow configuration consists of a frame construction for the selected membrane Table 12.4 Characteristics, advantages and disadvantages of plate and tubular membrane Low blocking, low pressure drop, gel layer controlled High surface area-volume ratio, low...

The Concentration Mass Flow Rate Diagram and the Graphical Solution

Free Printable Masks Patterns

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...

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...

Anaerobic Expanded and Fluidized Bed Reactors

In both systems, small particles are used as carriers for biofilms (bioparticles). Frequently, silica sand with a diameter of 0.2-0.5 mm and a specific density of 2.65 g cm-3 or activated carbon particles with somewhat higher diameters and a lower density are used. The upward flow rate must be high enough to expand the bed and the wastewater must be recycled at a much higher rate than in fixed bed reactors (Fig. 8.10). Expanded beds are expanded by 15-30 and fluidized beds by 30-300 , relative...

Early Biological Wastewater Treatment Processes

The collection of wastewater in canal systems served a purpose, but its discharge into rivers was no solution of the problem, if the amount of wastewater discharged was too great in comparison with the river flow rate. In Berlin, Hobrecht proposed and built a wastewater collecting system consisting of 12 radial arms - five to the south and seven to the north of the river Spree. In each radial system, rainwater and wastewater flowed to a central lowest point by gravity (and the system is still...

Concentration Polarization Model

The classic concentration polarization model describes the fluxes according to con-vective flow and retransfer of the solute, i.e. back diffusion through concentration boundary layer dependent on the concentration gradient between the bulk region and the surface of the membrane (Fig. 12.5). One solution to the mass balance in the boundary layer with thickness 8 is obtained at steady state conditions, dJx dz 0. There are two parts of the total flux the flux of the solute counter to the...