Agnieszka Montusiewicz

Improvement of counting helminth eggs with internal standard.

The sanitary regulations introduce a requirement for parasitological control of sewage water used for irrigation and fertilisation of crops. The existing methods of estimation of helminth eggs, based on the coproscopic method using sedimentation, desorption, centrifugation and flotation of the material, allow for only 30-75% efficiency. The aim of this paper is to present an improved quantitative estimation method. The proposed method is based on an internal standard. A predetermined number of eggs of Ascaris lumbricoides suis L is coloured with crystalline violet. These marked eggs are added to sample being examined. Counting the marked eggs in the sample and comparing them with their introduced number allows to estimate the efficiency of the procedure. This results in an increase in the efficiency of the method to 100%. It is possible to calculate the real number of helminth eggs in the sample on the basis of the estimated efficiency of the procedure. The sensitivity of the proposed method is at the level of about 0.4 ppm. The necessary number of replications in the method is about 10 times lower than that in the existing methods. The number of natural (not coloured) eggs does not influence the efficiency of the method with an internal standard.

MEASUREMENT OF ACTIVATED SLUDGE PARTICLE DIAMETERS USING LASER DIFFRACTION METHOD

Abstract The paper presents a study on the possibility of using the laser diffraction method for measuring the size of the activated sludge particles. Susceptibility of the particles to mechanical disintegration, dependent on the programmed value of stirring intensity, was observed (stirring was caused by required dynamic flow of analysed suspension through the measurement unit). According to the conclusions presented in this paper, it may be assumed that the laser diffraction method can be applied for measurement of activated sludge particle diameters under the following conditions: 1) the size of activated sludge particles measured by the laser diffraction method is not a real value, but after standardisation of measurement conditions can be treated as a parameter describing the sludge; 2) the particle diameters of activated sludge should be stabilised before the measurement, eg by mixing in the measurement unit or by ultrasound waves application. Abstrakt Praca dotyczy oceny możliwości wykorzystania dyfrakcji laserowej do badania rozmiarów kłaczków osadu czynnego. W czasie pomiarów zaobserwowano podatność analizowanych cząstek na zniszczenie mechaniczne zależną od zaprogramowanej intensywności mieszania (mieszanie i przepompowywanie jest wymagane w celu wymuszenia przepływu analizowanych zawiesin przez układ pomiarowy). Na podstawie wniosków opracowanych na podstawie prowadzonych badań można stwierdzić, iż metoda dyfrakcji laserowej może być stosowana do pomiarów rozmiarów kłaczków osadu czynnego pod następującymi warunkami: rozmiary kłaczków oraz pozostałych elementów osadu czynnego uzyskane w czasie pomiarów nie mogą być traktowane jako wartość bezpośrednia opisująca rozmiary kłaczka, lecz po standaryzacji warunków pomiarowych może być traktowana jako ilościowy parametr opisujący właściwości osadu czynnego. Przed pomiarem metodą dyfrakcji laserowej osad czynny powinien być uprzednio stabilizowany na przykład za pomocą mieszania w układzie pomiarowym bądź też za pomocą ultradźwięków.

Application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate

In this study, the application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate was investigated. Three configurations of cavitation device were examined and operational parameters of the process were selected. The study indicated that the orifice plate with a 3/10mm diameter conical concentric hole, characterized by the cavitation number of 0.033, is a reasonable choice to ensure the enhanced biodegradability of mature leachate. Using such a configuration and maintaining 30 recirculation passes through the cavitation zone at inlet pressure of 7 bar, the highest increase of biodegradability index (BI) of approximately 22% occurred, i.e., from the value of 0.046 to 0.056. The FT-IR/PAS analysis confirmed a degradation of refractory compounds that typically prevail in mature leachate. An evaluation of energy efficiency was made in terms of the actual consumed energy measured by using the Kyoritsu KEW6310 Power Quality Tester. A cavitational yield of 9.8 mg COD kJ(-1) was obtained for the optimum configuration and 30 recirculation passes. Regarding energy efficiency, the application of 10 cavitation cycles appeared to be the most profitable. This was due to an almost threefold higher cavitational yield of 27.5 mg COD kJ(-1). However, the preferable option should be selected by considering a satisfactory effect in the biodegradability enhancement.

Mature landfill leachate utilization using a cost-effective hybrid method

The main goal of this study was to investigate the co-digestion of sewage sludge and mature landfill leachate pretreated through hydrodynamic cavitation. The process efficiency was analyzed from the aspects of organics removal, biogas production, kinetics and digestate quality. Energy efficiency of the overall treatment was evaluated as well. A dose of hydrodynamically cavitated leachate of 5% v/v was used as a substrate for co-digestion with sewage sludge at a hydraulic retention time of 20 days. This improved the kinetics, biogas production and corresponding yields, as well as digestate quality. Fourier transform infrared photoacoustic spectroscopy analysis seemed to indicate that no new toxic compounds were formed with co-digestion. The investigated two-stage treatment is recommended as a safe and cost-effective method of utilizing mature leachate.

METHODS APPLIED FOR MEASUREMENT AND VISUALIZATION OF CHANGES IN BIODIVERSITY

Abstract The article presents the possible methods for determining biological or statistically significant differences between taxocenoses compared with respect to biodiversity. To obtain a complete description of biological differences between the compared hypothetical communities, the following indices were calculated: S (taxon richness), H (the Shannon index), Hmax (the maximum value of the Shannon index for the richness of taxa represented by the same number of individuals), Vd (a percentage value of covering the structural capacity of community, “evenness deficiency”), E (the MacArthur index - a taxon number (S) in a community for which the observed value of H equals Hmax), and Ps (a taxon richness shortage in percents). Moreover, a graphic profile method (Дд, Tj, and Lj profiles) was used for comparing the diversity of the communities. To obtain information about statistically significant differences in biodiversity between the analysed communities, rarefaction curves were applied. The curves are based on the null models and the Monte Carlo method. The rarefaction method resulted in determination of the statistical significance of the differences between taxon richness and Shannons index values for the compared communities. The Vd and Ps indices and the profile method allowed concluding about the significance of the biological differences between taxocenoses, even when their values of Shannons H indices were numerically similar.