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Sposób likwidacji uciążliwych zapachów powstających w procesie mechanicznego odwadniania komunalnych osadów ściekowych

Piecuch T., Kowalczyk A., Kupś D., Gomółka D.

Rocznik Ochrona Środowiska

2011

Tom 13

748-768

Katedra Techniki Wodno-Mułowej i Utylizacji Odpadów Politechniki Koszalińskiej od wielu lat prowadzi prace badawcze nad produkcją olejków eterycznych pozyskiwanych z surowców roślinnych w procesie destylacji parą wodną, a następnie wykorzystuje je do maskowania nieprzyjemnych zapachów wydzielających się ze ścieków w halach technologicznych (rozpylanie wyprodukowanych ekstraktów zapachowych za pomocą zraszaczy ręcznych) [1, 12÷15, 20]. Na podstawie przeprowadzonych analiz, zaproponowano zupełnie nowe rozwią-zanie, które także prowadzi do zmniejszenia uciążliwości odorów. Polega ono na tym, aby w miejsce stosowanych flokulantów do procesu mechanicznego odwadniania komunalnych osadów ściekowych i innych, zastosować jako substytut flokulantów, olejki eteryczne wyprodukowane z surowców roślinnych w procesie destylacji parą wodną; metoda ta została opatentowana [21]. Zatem, właśnie najważniejszym celem niniejszej pracy jest przedstawienie sposobu zmniejszenia uciążliwości zapachowej podczas mechanicznego odwadniania komunalnych osadów ściekowych poprzez zastosowanie olejku eterycznego, jako substytutu flokulantu w procesie sedymentacji odśrodkowej.

Emission of unpleasant odours is noxious for both plant workers and residents of surrounding areas, where odours are emitted. In the case of low emissions, the concentration of odour substances are low, and despite of the low odour detection thresholds, they cause significant noxiousness, it is possible to use masking agents. This issue is within range of interest of Division of Water-Sludge Technology and Waste Utilisation of Koszalin University of Technology, where for a few years works are conducted on production of an effective and inexpensive agent for decreasing nuisance of odours. Natural essential oils extracted from fresh plant materials in the process of steam distillation are used as masking agents. The aim of this study was to present a method of reduction of odour nuisance during dewatering of municipal sewage sludge by dosage of the essential oils from grapefruit and mint as a substitute of flocculant in the process of mechanical dewatering. Research on the use of essential oils for masking of odours were divided into two stages. In the first stage of the research essential oils of grapefruit and mint in the process of steam distillation were produced. Then, produced oil was used in the second stage of research as an agent for masking odour during municipal sewage sludge dewatering. Oils were dosed into sewage sludge before dewatering together with flocculant. Sludge dewatering process was carried out on a laboratory centrifuge MPW 350. As a input to dewatering process a real stabilized in the process of methane fermentation sludge was used, taken from the Wastewater Treatment Plant Jamno, directly from the pump pipe connecting fermentation tanks with centrifuges. Constant parameters of centrifugal sedimentation were: rotation time t [min] (assumed centrifugation time t = 1 min) and rotation speed n [rpm] (assumed n = 2400 rpm). Independent variable process parameters were: dose of flocculant C [kg/Mg of dry mass] and dose of essential oil D [cm3/100 cm3 of sludge] kind of oil used. Essential oils, which were produced from grapefruit and mint were dosed to the feed (sewage sludge with flocculant) before dewatering process in four doses: D1 = 0 cm3 of oil/100 cm3 of sludge, D2 = 2 drops of oil = 0.06 cm3/100 cm3 of sludge, D3 = 4 drops of essential oil = 0.12 cm3/100 cm3 of sludge and D4 = 6 drops of essential oil = 0.18 cm3/100 cm3 of sludge and then period of time of essential oil smell lasts in eluate and sludge after centrifugation process was examined. The study showed that the essential oils from grapefruit and mint effectively neutralize odours of sludge and eluate, produced during dewatering of municipal sewage sludge on the laboratory sedimentation centrifuge. With an in-creasing dose of essential oil of lemon, time of neutralisation of odours after dewatering is increasing, both for the dewatered sludge and eluate. It was also found that essential oils as hydrophobic substances have additional function of coagulants or flocculants, and improve the quality of the mechanical dewatering.

Electronic structure of the intermetallic rare earth compounds

Szytuła A., Gomółka D., Jezierski A., Penc B., Wawrzyńska E., Winiarski A.

Materials Science Poland

2006

Vol. 24, No. 3

557--561

The electronic structures of intermetallic rare earth compounds of different compositions: RMn2Ge2 (R = Nd, Sm), R3Mn4Sn4 (R = La, Ce, Nd), Ce3Ag4X4 (X = Ge, Sn), and Ce2MnGe6, have been investigated. XPS measurements were performed using a commercial LHS10 spectrometer. The valence band and core-level states have been analysed. In Mn compounds, the Mn 3d state forms a broad band near the Fermi level. The analysis of XPS spectra using the Gunnarsson-Schönhammer model gives the coupling parameters (hybridisation energy) between the R 4f states and electrons of the conduction band