Ratio of abundances of ciliates behavioral groups as an indicator of the treated wastewater impact on rivers

A method for assessing the degree of impact of wastewater treatment plant discharge on receiving rivers was proposed, based on the structural indicators of the population of ciliated protozoa. It was shown that the ratio of attached, crawling and free-swimming forms in bottom sediments changes under the influence of discharge. In the points subject to organic pollution, the share of attached filter-feeding bacteriovorous ciliates increases in the assemblage of ciliated protozoa. The proposed Attached Form Index (AFI) takes this ratio into account. The use of AFI makes it possible to assess the restructuring of the assemblage of ciliated protozoa under the influence of point sources of pollution, to establish a zone of negative influence of runoff, to assess the degree of restoration of the aquatic ecosystem, as the influence of the pollution source weakened

Contribution of prokaryotes and eukaryotes to CO2 emissions in the wastewater treatment process

Reduction of the greenhouse effect is primarily associated with the reduction of greenhouse gas (GHG) emissions. Carbon dioxide (CO2) is one of the gases that increases the greenhouse effect - it is responsible for about half of the greenhouse effect. Significant sources of CO2 are wastewater treatment plants (WWTPs) and waste management, with about 3% contribution to global emissions. CO2 is produced mainly in the aerobic stage of wastewater purification and is a consequence of activated sludge activity. Although the roles of activated sludge components in the purification process have been studied quite well, their quantitative contribution to CO2 emissions is still unknown. The emission of CO2 caused by prokaryotes and eukaryotes over the course of a year (taking into account subsequent seasons) in model sequencing batch reactors (SBR) is presented in this study. In this work, for the first time, we aimed to quantify this contribution of eukaryotic organisms to total CO2 emissions during the WWTP process. It is of the order of several or more ppm. The contribution of CO2 produced by different components of activated sludge in WWTPs can improve estimation of the emissions of GHGs in this area of human activity

Removal of Hardly Bio-Degradabale Organic Compounds from Wastewater by Means of Reagentless Methods

The paper discusses the issue of removing persistent organic pollutants (POPs) from wastewater, especially the polycyclic organic hydrocarbons (PAHs). The results obtained in literature studies indicate that the commonly employed traditional methods of wastewater treatment are not always efficient in eliminating the hardly bio-degradable pollutants. Therefore, extensive research is being conducted on the application of efficient POPs removal technologies. One of the considered variants involves incorporating advanced oxidation processes (AOP) into the wastewater treatment systems based on the biological processes. These include the reagentless methods, e.g. the processes involving ultrasounds and hydrodynamic cavitation. On the basis of the author’s own studies conducted in a laboratory system comprising a static cavitation reactor, the possibility of applying hydrodynamic cavitation for the decomposition of PAHs was evaluated on the basis of model solutions of anthracene and phenanthrene. It was shown that the employed advanced oxidation process with hydro-cavitation has a significant impact on reducing the concentration of the considered PAHs. It was confirmed that the degradation degree of a substance depends on the intensity and the course of the cavitation process. The energy efficiency of the conducted process was analyzed as well and expressed as the ratio pertaining to the amount of the degraded compound to the electric energy supplied to the system

Research on impact of selected parameters of hydrodynamic cavitation system on the anthracene and phenanthrene degradation degree in the cavitating liquid environment

The essence of the undertaken research was to analyze and evaluate the impact significance of cavitation process selected parameters on the course and efficiency of organic compounds degradation in hydrodynamic cavitation conditions in the aqueous environmenton the example of model compounds: anthracene and phenanthrene. As part of the research, the hydrodynamic cavitation reactor equipped with exchangeable cavitation inductor was designed and performed. In laboratory conditions, the effect of changes of chosen process parameters such as the inlet pressure and geometry of cavitation-generating component on the anthracene and phenanthrene degradation degree was examined. In terms of treatment technology, the range values knowledge of these parameters enables the induction of controlled phenomenon of hydrodynamic cavitationin the most efficient conditions. Conducted laboratory tests indicate that theuse of hydrodynamic cavitation is an effective process which allows to reduce the concentrations of anthracene and phenanthrene in model aqueous solutions. The selection of cavitation inductor configuration is a very important aspect while maximizing the technology effects

Study of the process of phenanthrene degradation in a cavitated liquid environment

W artykule przeanalizowano wyniki badań degradacji fenantrenu w roztworach modelowych, w układzie z reaktorem hydrokawitacyjnym. Dokonano oceny wpływu parametrów odnoszących się do konstrukcji reaktora, parametrów prowadzonego procesu kawitacji oraz stężenia początkowego roztworu, na przebieg oraz efektywność degradacji fenantrenu Określenie oddziaływania kawitacji hydrodynamicznej oraz zidentyfikowanie jej efektywności, w zależności od parametrów pracy układu hydrokawitacyjnego, ma zasadnicze znaczenie dla skutecznego projektowania i eksploatacji reaktorów hydrokawitacyjnych.The aim of the study was to analyse the results of the investigation of phenanthrene degradation in standard solutions within a system including a hydrodynamic cavitation reactor. The effect of the reactor’s structural parameters, the parameters of the cavitation process as well as the solution initial concentration on the course and effectiveness of phenanthrene degradation was estimated. It is essential for a successful design and exploitation of hydrodynamic cavitation reactors to identify the effect of hydrodynamic cavitation and assess its efficiency in relation to the parameters of the hydrodynamic cavitation system operation

Reduction of odour emission from wastewater from sugar industry with application of hydrodynamic cavitation

Obok substancji gazowych, które zagrażają człowiekowi wskutek toksycznego działania, występują substancje pogarszające komfort życia, choć często nie stanowią bezpośredniego zagrożenia zatruciem. Są to związki złowonne, uciążliwe dla człowieka nawet wtedy, kiedy występują w powietrzu w śladowych ilościach. Mogą wywoływać zmęczenie, senność, nadpobudliwość lub odczucie odrazy. Dezodoryzacja jest to usuwanie niepożądanego zapachu. Metody dezodoryzacji gazów odlotowych różnią się od typowych metod oczyszczania gazów. Celem dezodoryzacji nie jest usuwanie wszystkich zanieczyszczeń gazowych ale tylko tych zanieczyszczeń, które są odorantami.Elimination of odorous compounds constitutes an issue requiring individual approach to every single case. When designing a system for purification of effluent gases from malodorous compounds it is important to analyze the source of contamination in order to determine precisely the physicochemical character of arising odours. The choice of efficient deodorization method depends on, among others, an emission, the qualitative composition of emitted odours and the required purification degree. In spite of the existing numerous techniques for reduction of odour nuisance none of them can be regarded as a general-purpose way of treatment. Highly efficientsolutions are inherently connected with significant investment and exploitation expenses, whereas cheaper and less sophisticated methods do not often meet the required standards. This results in the necessity of searching for alternative techniques combining reasonable costs and acceptable performance. Non-conventional oxidation methods in liquid phase can be such a solution, in particular the hydrodynamic cavitation which is coved in this article. The paper presents problems connected with odour nuisance reduction in sugar industry. After finishing the beet campaign waste and technological waters are directed to sludge drying beds. Fermentation processes of organic compounds occurring during the clarification of water cause the formation of malodorous compounds being burdensome to the surroundings. In order to reduce the emission of odorants from waste and technological waters hydrodynamic cavitation was used which degraded organic compounds affecting the arising odours. Identification of odorous compounds emitted from sludge drying beds was obtained by means of gas chromatography. On the basis of the conducted laboratory tests the assumptions to pilot-scale design of the system utilising hydrodynamic cavitation for reduction of odours emission from wastewaters from sugar industry were developed

Study on the Influence of Selected Technological Parameters of a Rotating Biological Contactor on the Degree of Liquid Aeration

The subject of the research involves a rotating biological contractor with a bi-directional longitudinal flow as an element of a synchronized system of disposal and biological treatment of domestic wastewater in small-bore sewerage. The rotor design is based on a system of corrugated protective pipes, arranged in coils wound around its rotation axis. The pipes are wound in a way that enables a bi-directional flow of liquids. During the rotor rotation in wastewater, the contactor is simultaneously emptied and filled with wastewater. The role of corrugated protective pipes is twofold; on the one hand, they constitute a surface for the biofilm development and on the other, they enable the flow of liquids, thus ensuring its aeration. The contactor design aims to achieve intensive aeration of transported wastewater, which will allow for greater development of microorganism populations participating in hybrid wastewater treatment, i.e. the methods involving activated sludge and trickling filter. An analysis on the influence of rotor operation kinematics on the efficiency of liquid aeration was conducted. The aeration capacity for variable rotational speed (0.7 rpm, 1.5 rpm, 2.0 rpm, 3.0 rpm) and direction of the contactor rotating element were calculated. In the considered case, oxygen transfer coefficient KLa was within the range of 0.011÷0.023 1/min. The obtained results indicate a clear connection between the system kinematics and the degree of liquid aeration in the contactor

The Selection of Design Parameters of the Rotating Biological Contactor Using Tracer Studies

The subject of research consists in a rotational biological contactor with a rotor characterized by a bi-directional longitudinal flow as an element of synchronized system of disposal and biological treatment of sanitary wastewater in small-bore sewerage. The rotor design is based on a system of corrugated protective pipes, arranged in coils wound around its rotation axis. The corrugated pipes have two purposes. On the one hand, they ensure and enable the aeration of activated sludge, and provide the surface for biofilm development on the other. The special winding of corrugated pipes enables a bi-directional flow of the liquid medium. During the rotation of the rotor, the RBC is simultaneously emptied and filled with wastewater. The structure of the rotational biological contactor aims to provide intensive aeration of the transported wastewater, which would allow for a greater development of microorganisms participating in the hybrid treatment of wastewater, i.e. the activated sludge method and by means of a trickling filter. Design solutions of the rotor pertaining to coil arrangement and the drive system were analyzed and tracer studies of hydrodynamics were performed in regard to the selection of appropriate structural parameters of the device. The obtained results indicate a clear influence of the design solution and its kinematics on the aeration time of the flowing medium, which is one of the parameters governing the efficiency and quality of RBC operation