In certain concentrations, hydrogen sulfide – occurring in gaseous fuel – corrodes combustion chambers, contaminates and acidifies engine oil and has a destructive effect on engine seal components, valve seats and timing. Fuel in the form of digestate gas, before powering cogeneration units, must meet the standards set by the manufacturer of the unit. Whether such values can be achieved depends primarily on the concentration of hydrogen sulfide and the desulfurization method used. The purpose of the study was to determine the effectiveness of sulfur fixation in the sludge by dosing the PIX 113 coagulant directly into the feedstock before pumping into the chamber. The results obtained confirmed the effectiveness of the coagulant and provided the basis for conducting further studies using other products based on iron compounds. During the experiment, there were no negative effects of applying the coagulant to the batch just before pumping into the chamber. The positive aspects of sludge supplementation with the tested agent included an increase in biogas production due to a decrease in the H2S concentration and an improvement in biogas quality parameters – CH4 and CO2.
Coagulation is often used for the pre-treatment of industry wastewater, with effectiveness strictly dependent on technological conditions. This study aimed at determining what technological parameters of coagulation of cosmetic industry wastewater provide the highest efficiency of clarification. The dosages of reagents, the order of dosing, as well as the one- and two-stage processes were investigated. The samples of raw wastewater were collected from average daily effluent from a cosmetics manufacturing plant. Liquid coagulant PIX 111 (FeCl3) and NaOH as a pH-adjusting agent were used. Jar-test experiments were carried out to determine the optimum conditions for turbidity and total organic carbon (TOC) removal. The efficiency of clarification was high (90–99%) across a wide range of pH values (6–9) and coagulant doses (0.5–1.25 mL/L). What is important is that the coagulant dose of 0.56 mL/L provided 97.6% clarification efficiency without the addition of the alkali. The minimal stoichiometric excess of alkalinity for effective coagulation was 0.5 mmol/L. In all samples, the removal efficiency for TOC was lower than for turbidity, because some of the organic carbon forms were non-coagulating dissolved compounds. The wastewater from tonic and fluid production was very susceptible to coagulation. The addition of the coagulant before the alkali resulted in better wastewater treatment efficiency than the reverse order. Single-stage process with optimal doses of the reagents allowed to clarify wastewater to a level of 10 NTU. On the other hand, the two-stage process brought the turbidity down to 1 NTU level.
W pracy przedstawiono wyniki badania flokulacyjnych właściwości kationizowanej skrobi ziemniaczanej w obecności koagulantów żelazowego i glinowego. Wydajność sedymentacji modelowych zawiesin kaolinu określano metodą nefelomeryczną. Stwierdzono, że modyfikowana skrobia użyta w kompozycji z koagulantem znacznie wydajniej przyspiesza klarowanie zawiesiny mineralnej, niż flokulant czy koagulant stosowane pojedynczo. Przedawkowanie koagulanta (zarówno żelazowego jak glinowego) prowadzi do obniżenia wydajności flokulacyjnej kationizowanej skrobi.
EN
The work contains experimental data on flocculation abilities of cationized potato starch applied together with ferric and aluminum coagulants. The sedimentation efficiency for model kaolin suspensions has been determined with nephelometric method. It has been stated that modified starch used together with coagulant accelerates much more effectively the clarification of mineral suspension comparing to the flocculant or the coagulant used separately. Meantime, overdosage of the coagulant (both ferric and aluminum one) leads to decrease of flocculation efficiency of cationized starch.
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