DOI 10.35776/VST.2022.10.05
UDC 628.35
Stepanov S. V., Avdeenkov Pavel, Ponomarenko Ol’ga, MOROZOVA K. M.
Determination of kinetic constants and coefficients of biological processes of wastewater treatment of egg advanced processing enterprises
Summary
The results of studies carried out in contact conditions with active sludge of a laboratory batch reactor with wastewater from an enterprise for advanced processing of chicken eggs are presented. In the course of kinetic experiments based on measuring the rate of dissolved oxygen consumption the following averaged values of the kinetic constants of the biological treatment processes were established for wastewater after preliminary coagulation: the maximum rate of oxygen consumption at a sludge concentration ai → 0 ρ`max = 44.8 mg/(g·h) in terms of a temperature of 20°С; Michaelis constant Km = 77.5 mg/l; coefficient of inhibition by metabolic products φ=0.265; temperature constant χ = 0.08°С–1; optimal pH value 7.8 and pH constant 80. During the experiments with raw wastewater, the following average values of the constants were determined: the maximum rate of oxygen consumption at 20°С and ai → 0 ρ`max = 26.5 mg/(g·h); Michaelis constant Km = 50.6 mg/l; coefficient of inhibition by metabolic products φ=0.065; temperature constant χ = 0.1°С–1; pHopt 7.8 and KрН = 170. The obtained values of kinetic constants and coefficients can be used in the calculation of biological wastewater treatment facilities of an egg processing enterprise.
Key words
wastewater , biological treatment , kinetic constants , food industry , egg processing enterprise , batch reactor
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UDC 628.35
DOI 10.35776/VST.2023.05.05
Stepanov S. V., Avdeenkov Pavel, Ponomarenko Ol’ga, MOROZOVA K. M.
Optimization and technical and economic evaluation of the process flow schemes of wastewater treatment of a plant for chicken egg advanced processing
Summary
The results of searching for the optimal process scheme for wastewater treatment of an enterprise for advanced processing of chicken eggs are presented. The optimization was carried out in terms of the life cycle cost (LCC) for a period of 25 years operation for the newly built treatment facilities with a capacity of 600 m3/day. The considered options include mechanical, one- and two-stage aerobic biological treatment in a membrane bioreactor with nitri-denitrification, with primary chemical pressure flotation with different doses of coagulant and without flotation. Process design was made on the basis of experimentally determined technological and kinetic parameters. The economic feasibility of primary physical and chemical purification was proved, and what is more, the most cost-effective was the treatment with Aqua-Aurat™-14 coagulant trademark with a dose of 125 mg/l as Al2O3, corresponding to the highest efficiency of physical and chemical purification. Retrofitting chemical flotation into the process flow scheme provided for reducing LCC by 7.7%. It is shown that with the availability of physical and chemical treatment dividing biological treatment into two stages virtually produces no economic effect on LCC. Taking into account the lowest energy consumption and the size of the structures the most useful option turned out to be the one with primary physical and chemical treatment and single-stage aeration tanks. The cost of wastewater treatment in this case was 99.66 RUB/m3, or 18.62 RUB/kg BODtot. For all the considered options in the LCC structure, the capital costs had the highest value – 22.2–27.9%, the payroll fund – 17.3–19.2%, equipment replacement – 17.4–19%.
Key words
wastewater , biological treatment , optimization , life cycle cost , physical and chemical treatment , egg processing enterprise , technical and economic evaluation , cost of wastewater treatment
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DOI 10.35776/VST.2022.09.05
UDC 628.35
Stepanov S. V., Avdeenkov Pavel, Ponomarenko Ol’ga, MOROZOVA K. M.
Results of studies of biological wastewater treatment of an egg processing enterprise
Summary
Biological treatment of wastewater of an enterprise for enhanced processing of chicken eggs in a batch reactor (SBR) has been studied. The treatment of both raw and pre-coagulated wastewater under aerobic and anoxic-aerobic conditions was studied in a 5-liter experimental unit for four months. In the course of the experiment in the treatment of raw wastewater with an average COD sludge load of 0.18 g/(g·day), average concentrations of pollution in the effluent were obtained, mg/l: COD – 253, BODtotal – 58.4, suspended solids – 11, ammonia nitrogen – 2.1, nitrite nitrogen – 0.06. The average values of the specific rate of oxidation of organic substances as COD, normalized to 20°С, amounted to 9.8 mg/(g·h); as BODtotal 7.2 mg/(g·h). While operating SBR with wastewater after physical and chemical treatment, with an average COD load of sludge of 0.15 g/(g·day), the effluent was characterized by the following average values, mg/l: COD – 99; BODtotal – 15.4; suspended solids – 10; N–NH4 – 1; N–NO2 – 0.04. The average values of the specific rate of oxidation of organic substances as COD at 20°С turned out to be 8.3 mg/(g·h) and as BODtotal – 5.7 mg/(g·h). The concentrations of nitrogen nitrates in the effluent in two anoxic phases in the SBR cycle averaged as follows: during raw wastewater treatment – 21.7 mg/l, and during pre-coagulated wastewater treatment – 15 mg/l.
Key words
wastewater , biological treatment , food industry , egg processing enterprise , batch reactor
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DOI 10.35776/VST.2022.12.04
UDC 628.35
Stepanov S. V., Avdeenkov Pavel, Ponomarenko Ol’ga, MOROZOVA K. M.
Results of studying biological treatment of wastewater of an egg processing enterprise in a pilot membrane bioreactor
Summary
The results of studies on the biological treatment of wastewater of an enterprise for advanced processing of chicken eggs in a pilot membrane bioreactor (MBR) with preliminary denitrification are presented. It is shown that the key indicator of pollution the treatment facilities shall be calculated on is BODtotal. At loads on the ash-free basis of activated sludge according to BODtotal from 0.06 to 0.125g/(g·day) for raw wastewater and from 0.04 to 0.12g/(g·day) for wastewater after preliminary coagulation and settling, BODtotal of permeate was 8–12 mg/l, and the concentrations of ammonium and nitrite met the MPC for fishery water bodies. The minimum recirculation that provided for the concentration of nitrate nitrogen in the effluent at the MPC level, turned out to be eight-fold for raw wastewater and six-fold for the pre-coagulated one. The inert part of COD was about 90 mg/l. On the basis of the executed studies the kinetic constants of the oxidation of organic substances required for the calculation of industrial biological treatment facilities were determined: ρ´max for BODtotal – 29.9 and 30.4 mg/(g·h), Km for BODtotal – 34.7 and 25.2 mg/l for raw wastewater and wastewater after preliminary physical and chemical treatment, respectively. The total volumes of bioreactors with a capacity of 600m3/day, operating with an activated sludge dose of 8 g/l according to the MBR technology with preliminary denitrification, while providing for the treatment level of BODtot of 12 mg/l and removing nitrogen compounds to the MPC for fishery water bodies, amounted to 3716 and 1643m3 for raw wastewater and wastewater after preliminary physical and chemical treatment, respectively.
Key words
wastewater , biological treatment , kinetic constants , membrane bioreactor , food industry , egg processing enterprise
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DOI 10.35776/VST.2022.05.04
UDC 628.345
Stepanov S. V., Avdeenkov Pavel, Ponomarenko Ol’ga, MOROZOVA K. M.
The results of studies of physical and chemical wastewater treatment of an egg processing enterprise
Summary
The composition of wastewater of an enterprise for advanced processing of chicken eggs characterized by the following parameters: COD 3,600–12,200mg/l, concentration of suspended solids 1,206–3,031 mg/l, BODtotal 2,534–8,540 mg/l, no phosphates, pH 5.4– 13.2 was studied. The concentration of nitrogen compounds, mg/l, varied within the following ranges: ammonium – 0.4–11.4; nitrates – 0–15.3; nitrites – 0–7.3; organic nitrogen – 26.6–89.7. Based on the results of test coagulation, the optimal coagulant chosen was low-basic polyaluminum chloride brand «Aqua-AuratTM-14» with a dose of 125 mg/l as Al2O3. The average treatment efficiency while using this coagulant was, %: for COD – 77.3; for BODtotal – 76.3; for suspended solids – 80.1; for organic nitrogen – 58.7. The lowest concentration of residual aluminum 0.31 mg/l at the initial concentration of 0.29 mg/l corresponded to pH 6.7–7. Unit costs for the coagulant amounted to 9.37 rubles/m3.
Key words
wastewater , coagulation , aluminium polyoxychloride , food industry , physical and chemical treatment , egg processing enterprise
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