Thesis (M.S.)--University of Tennessee, Knoxville, 2001. / Title from title page screen. Document formatted into manuscript-like pagination: x, 128 leaves : ill. (some col.). Vita. Includes bibliographical references (leaves 114-122).

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 55 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 45-46).

Constructed wetlands (CWs) originate from natural wetlands and are used for waste water treatment as an alternative to conventional treatment. This thesis was aimed at providing a literary summary of the types of house sewage water treatment plants and constructed wetlands used in the CR and abroad, of their hygienic aspects, functionality, treatment efficiency, expensiveness and the possibilities of their use in the conditions of the CR and their advantages and disadvantages. It also deals with a proposal of a suitable type of house CW for the conditions of the CR and a list of the necessary steps in construction of a house CW. Quite similar systems are being used for house sewage treatment in the Czech Republic and abroad {--} mostly septic tanks, ground mounds, constructed wetlands, active treatment plants and biodiscs. Alternative water treatment methods are generally not suitable for buildings having (now or in the future) the possibility of connection to municipal sewerage systems. They are on the other hand suitable for buildings not connected to sewerage systems or for seasonal objects, remote places and holiday houses with seasonal waste water production. A system with horizontal subsurface flow is mostly used as a CW in the Czech Republic. This CW type ensures sufficient removal of organic contamination and insoluble substances, but the efficiency of nitrogen and phosphorus removal is relatively low. However it is fully sufficient in the instance of low PE numbers, as the loading rate is usually low and the concentration of contaminants in the output water meets the prescribed limits. Foreign researches show that hybrid systems combining horizontal flow with vertical flow and with recirculation are more suitable for improving efficiency of nitrogen removal. Systems with vertical flow and intermittent waste water dosage showing particularly good results in ammoniac removal are also suitable for nitrogen removal. Special materials with higher iron, aluminium or calcium content are most suitable as filling of a constructed wetland or as additional filters or for improvement of phosphorus removal from waste water as they are able to reach efficiency of up to 90 %. In my thesis I came to a conclusion that a CW with horizontal subsurface flow is the most suitable type of house constructed wetland treatment for the conditions in the CR, mainly because it is the most frequently used and thus best proven CW type with sufficient efficiency of treatment for the substances required by standards.

Water is a fundamental need for existence of mankind. Only 0.01 % of total global water is readily available for human consumption as fresh water. The rapid increase in human population and consequent rise in urbanization and industrialization is producing a stress on this meager water resource. Water at the same time is a renewable resource, ie with suitable treatment it can be made re-useable. Aeration is one of the important processes employed in activated sludge process of the biological treatment units of wastewater. In this process the level of dissolved oxygen in the effluent is raised to the required amounts to decompose organic matters present in the effluent and thereby to reduce the BOD (biochemical oxygen demand) of the effluent by a physical means called “aeration process”. The aeration process consumes as much as 60-80% of total power requirements of wastewater treatment plants. Therefore, the efficiency in design of aeration process is required so that treatment and its power consumption can be economized. With the objective of optimizing the aeration process the present work in this thesis endeavors to develop an aeration which is efficient as well as economical. The various geometric parameters that affect the aeration process in mechanical surface aerators have been optimized. In the present work circular surface aeration tanks have been used. There are two types of circular tanks: Baffled and unbaffled. Separate optimal geometric parameters have been obtained for baffled and unbaffled circular tanks. With optimal geometric similitude scale up studies were done. Reynolds number and Froude number criteria has been found unsuitable for scaling oxygen transfer rates. Theoretical power per unit volume parameter is the most suitable scaling parameter for oxygen transfer rates in both baffled and unbaffled circular tanks. Baffled circular tanks are found to give better performance in terms of oxygen transfer rates as compared to unbaffled tanks. In contrast unbaffled tanks give better performance in terms of power consumption as compared to baffled circular tanks. General correlations have been developed for oxygen transfer rates for both baffled and unbaffled circular surface aerations tanks which incorporate all the geometric and dynamic parameters. These correlations help in the design of new treatment facilities as well as evaluating and up gradation of existing facilities. Power consumption studies have also been conducted on circular surface aeration tanks. Geometric parameters affect the power consumption significantly. Using the optimal geometric similarity conditions obtained for oxygen transfer rates the scale up studies for power consumption has also been done. Reynolds and Froude criteria are found to be giving scale effects for non dimensional power consumption parameter, power number. Theoretical power per unit volume parameter is found to be the scaling parameters for power number and a suitable correlation equation has been developed for baffled circular surface aeration tanks. General correlations have been developed for power number in baffled and unbaffled circular tanks. A novel type of self aspirating tube sparger system has been developed. It is like a bubble aerator with a rotor. The various geometric parameters that affect oxygen transfer rates have been optimized in baffled circular surface aeration tank. The optimal geometrically similar tanks have been used for scale up studies. Theoretical power per unit volume parameter is found to be the scaling parameter for oxygen transfer rates in circular surface aeration tanks with self aspirating sparger systems. Circular baffled tanks with a special sparger system gives very much higher oxygen transfer rates (as much as 5.7 times) as compared to circular tanks. The oxygen transfer rates data from literature also show lower values as compared to the system developed in this thesis. Geometrically similar unbaffled tanks have also been used with self aspirating sparger system. For same power consumption oxygen transfer rate in circular surface aeration tanks with self aspirating sparger system is higher as compared to circular tanks without self aspirating system. Mixing mechanisms in surface aeration tanks depend upon two different extreme length scales of time, namely macromixing and micromixing. Small scale mixing close to the molecular level is referred to as micromixing; whereas macromixing refers to the mixing on a large scale. The effect of geometrical parameters on macromixing time has been studied. The scaling parameters for macromixing and micromixing have been developed and simulation equations governing these time scales are also presented.