Ecological and economic efficiency of growing on dark gray soils of bean-cereal grasses

Saabunud / Received 02.05.2022 ; Aktsepteeritud / Accepted 14.07.2022 ; Avaldatud veebis / Published online 14.07.2022 ; Vastutav autor / Corresponding author: Yevheniia Butenko ; [email protected] efficiency of growing leguminous and cereal agrophytocenoses (Trifolium pratense and Medicago sativa sown with the addition of Bromus inermis, Lolium multiflorum, Festuca rubra), highlighted their economic and energy advantages over cereal grasses. The article presents the results of the study of the influence of grass mixtures on the main indicators of the efficiency of growing sowing phytocenoses during haymaking in the Carpathians on dark grey soil. Growing agrophytocenoses without mineral fertilizers ensures the maintenance of 370–520 € ha–1 of net profit, with the profitability of 151–187%, the cost of 1 ton of feed units – 56.7–66.7 €, bioenergy coefficient – 2.5–2.9, energy efficiency ratio – 5.8–6.5 and energy consumption per 1 ton of feed units – 4.0–4.7 GJ. The cultivation of alfalfa-cereal grasses is ensured on dark-wet soil with three years of use of the best indicators of economic and energy efficiency. It was found that on both experimental bean–cereal grasses the highest efficiency is maintained when P60K60 is applied in combination with inoculation of seeds of bean strains of nodule bacteria

Optimal parameters for reagent treatment of Hrybovychi landfill leachates at the pilot-scale treatment plant

Promising technologies for the treatment of solid waste landfill leachates are considered with an emphasis on reagent and combined methods. The purpose of this study was to estimate at the pilot-scale level optimal technological parameters of the leachate oxidation using the modified Fenton process, accompanied by the simultaneous coagulation-flocculation followed by gravitational sedimentation. Pilot-scale leachate treatment plant was installed at the Hrybovychi MSW landfill (Ukraine), and reagent treatment of leachate was a second stage treatment after the aerobic biological pre-treatment. Reagent treatment unit worked in a batch mode, with nominal volume of treated leachate 100 dm3 per cycle. Dependencies of the key pollution indicators (ammonium nitrogen, total Kjeldahl nitrogen, BOD, COD, pH, suspended solids) versus the dosage of reagent solutions are obtained. The optimum specific dosages of reagent solutions are found to be equal: 0.04 m3 of PAA 0.1 wt% solution per 1 m3 of leachate;  Al2(SO4)3×18 H2O (10 wt.%) – 0.03–0.04 m3/m3; FeSO4×7H2O (10 wt.%) – 0.06–0.08 m3/m3; hydrogen peroxide (10 wt.%) – 0.04–0.05 m3/m3. High efficiency of COD reduction (88.2–89.5%) is obtained at optimal doses of reagent solutions, and the optimum [H2O2]/COD ratio was found to be 0.23–0.25. Obtained maximum effects of COD reduction significantly exceed corresponding effects for the simple Fenton process reported before. This result could be explained by the synergistic effect of additional flocculation and coagulation immediately before the input of Fenton reagent. Results of the study showed the efficiency of the proposed treatment technology and allow recommending this technology for the implementation at landfill leachate local treatment plants

The Use of Binders of Natural Origin to Improve the Technology of Creating Fuel Briquettes from Wood Waste

The method of wood waste utilization by pressing it into fuel briquettes is considered. It is proposed to use sulfate soap, a multi-tonnage waste of the pulp and paper industry, as an astringent. It is proven that as a result of adding a binder to the raw material, it is possible to carry out the process of forming briquettes with lower pressures, while ensuring the necessary statistical strength of the briquette. An appropriate method of supplying the binder is its preliminary mixing with wood waste. The most suitable concentration of the binder for fuel briquettes amounts to 6%. The use of a binder made it possible to reduce engine power by 40%, as well as increase the density of the obtained fuel briquettes by 10%