Kinetics and Performance of Biological Activated Carbon Reactor for Advanced Treatment of Textile Dye Wastewater

The kinetics and performance of a biological activated carbon (BAC) reactor were evaluated to validate the proposed kinetic model. The Freundlich adsorption capacity (Ka) and adsorption intensity constants (n) obtained from the batch experiments were 1.023 ± 0.134 (mg/g) (L/mg)1/n and 2.036 ± 0.785, respectively. The effective diffusivity (Ds) of the substrate within the activated carbon was determined by comparing the adsorption model value with the experimental data to find the best fit value (4.3 × 10–4 cm2/d). The batch tests revealed that the yield coefficient (Y) was 0.18 mg VSS/mg COD. Monod and Haldane kinetics were applied to fit the experimental data and determine the biokinetic constants, such as the maximum specific utilization rate (k), half-saturation constant (KS), inhibition constant (Ki), and biomass death rate coefficient (kd). The results revealed that the Haldane kinetics fit the experimental data better than the Monod kinetics. The values of k, KS, Ki, and kdwere 3.52 mg COD/mg VSS-d, 71.7 mg COD/L, 81.63 mg COD/L, and 4.9 × 10−3 1/d, respectively. The BAC reactor had a high COD removal efficiency of 94.45% at a steady state. The average influent color was found to be 62 ± 22 ADMI color units, and the color removal efficiency was 73‒100% (average 92.3 ± 10.2%). The removal efficiency for ammonium was 73.9 ± 24.4%, while the residual concentration of ammonium in the effluent was 1.91 ± 2.04 mg/L. The effluent quality from the BAC reactor could meet the discharge standard and satisfy the reuse requirements of textile dye wastewater.

MILK PRODUCTIVITY AND TRUENESS TO TYPE OF BROWN SWISS COWS OF THE SMOLENSK REGION

Изучена молочная продуктивность коров бурой швицкой породы и определена ее производственная типичность в условиях Смоленской области. Исследования показали, что в породе преобладают животные молочного (36%) и низкомолочного (31%) типов, при этом высокомолочные коровы составляют 26% от всего поголовья. Рассчитанные усредненные значения коэффициента производственной типичности (КПТ) и индекса производственной типичности (ИПТ) находятся в пределах 3,00—3,99 ед., то есть изучаемых животных возможно отнести к классу молочных. Отмечено снижение значений результатов типичности от 1-ой к 3-ей лактации на 0,04—0,03 ед. (Р≤0,001).Экстерьер коров в зависимости от производственного типа имеет, в основном, недостоверную разницу между значениями промеров, но позволяет определить их соответствие типу. Следует отметить значительную разницу у коров всех лактаций глубины груди — 8,4—10,0 см (Р≤0,001), косой длины туловища — 5,6—8,2 см (P≤0,001). Интенсивность удоя в первую и вторую фазы лактации в зависимости от производственного типа увеличивается от 1-й к 3-й лактации. У коров всех производственных типов происходит снижение коэффициента устойчивости от 1-й к 3-й лактации и составляет 0,9—13,3%. Результаты коэффициента молочности постепенно увеличиваются от 1-й лактации к 3-й, кроме группы высокомолочных коров. Полученные данные обеспечат достоверность отбора лучших животных для дальнейшей селекции, повысят точность определения производственного типа, ускорят проведение оценки, поскольку для установления направления продуктивности животных целесообразно ее проводить по окончании 1-й лактации путем расчета КПТ и ИПТ. Итог — получение стад соответствующего направления продуктивности в зависимости от пожеланий собственника. The milk productivity of Brown Swiss cattle was studied and its trueness to type assessment was carried in the Smolensk region. The survey of the breed was showed that it is dominated by animals of the milk (36%) and low-milk (31%) types, while high-milk ones make up 26%. The observed average values of the trueness to type coefficient (TTC) and the index trueness to type of (ITT) are in the range of 3.00—3.99 points, that is, the studied animals may be classified as milk. There was a decrease the results to type from 1 to 3 lactation by 0.04—0.03 points (P≤0.001). The exterior of cows, depending on the production type, has mainly an unreliable difference between the values of body measurements, but what it allows to determine their compliance with the trueness to type. It should be noted a significant difference in the chest depth in all lactation 8.4—10.0 cm (P≤0.001), the oblique body length 5.6—8.2 cm (P≤0.001). The rate of production in the first and second phases of lactation, depending of the trueness to type, increases from 1 to 3 lactation. In all cow’s trueness to types, the coefficient of lactation stability decreases from the first to the third lactation and is 0.9 - 13.3%. The results of the milk yield coefficient gradually increase from 1 lactation to 3, except for the group of high-milk cows. The obtained results will ensure the reliability of the selection of the best animals for further breeding, increase the accuracy of determining the trueness to type, step up the assessment, since it is advisable to conduct it after the end of the first lactation by calculating the TTC and ITT to determine the direction of animal productivity. The result is the receipt of herds of the appropriate direction of productivity, depending on the wishes of the owner.

Efficiency studies of modified IFAS-OSA system upgraded by an anoxic sludge holding tank

An upgraded integrated fixed-film activated sludge-oxic settling anoxic (IFAS-OSA) system is a new technology for reducing nutrients and excess sludge. The results showed that the average TN removal efficiency of the IFAS-OSA system was gradually increased up to 7.5%, while the PO4–3-P removal efficiency increased up-to 27%, compared with that of the IFAS system. The COD removal efficiency of the IFAS-OSA system was slightly increased up-to 5.4% and TSS removal efficiency increased up to 10.5% compared with the control system. Biomass yield coefficient (Yobs) in the IFAS and IFAS-OSA systems were 0.44 and 0.24 (gr MLSS/ gr COD). Hence, sludge production decreased by 45%. The average SVI was decreased by 48% in IFAS-OSA system compared with IFAS. This study demonstrated the better performance of the IFAS-OSA system compared to that of the IFAS system.

MODEL ESTIMASI BIOKINETIKA UNTUK PROSES POST-DENITRIFIKASI AIR LIMBAH DOMESTIK PADA UNIT ANAEROBIC BAFFLED REACTOR

This study developed a combination of Continuous Stirred Tank Reactor (CSTR) for the acid fermentation and the Anaerobic Baffled Reactor (ABR) post-denitrification through high nitrite injection. Volatile Fatty Acids (VFAs) as a substrate for the post-denitrification process were optimally produced in the acid fermentation process. The aim of this study was to obtain the estimation of biokinetic values to predict the effluent wastewater quality in ABR post-denitrification process under unsteady state. The reactor was operated for HRT 7 days at temperature 25-28 ˚C and pH 6-7,2. The influent and effluent substrate concentration were monitored continuously for 160 days. Post-denitrification biokinetic from the Contois equation resulted in the value of hydrolysis rate (Kh) of 0.077 day-1, the substrate transport rate (k) of 4.364×10-6 Lmg-1day-1, maximum specific growth rate (μmax) of 0.559 day-1, half saturation constant (KS) of 0.209 mgL-1, microbial decay coefficient (b) of 0.0145 days-1; yield coefficient (Y) of 0.084 g-VSSg-COD-1. The validation of biokinetic parameters based on statistical analysis showed fairly precise results following the trend of experimental data to determine the substrate concentration in the effluent unit. Therefore, the biokinetic values can be applied in the design of ABR post-denitrification using primary sludge incorporation with high strength nitrate.Keywords: Anaerobic baffled reactor, biokinetics, Contois, hydrolysis, post-denitrification.

Performance evaluation and substrate removal kinetics in a thermophilic anaerobic moving bed biofilm reactor for starch degradation

A laboratory-scale anaerobic moving bed biofilm reactor (AnMBBR) was installed and operated at various hydraulic retention times (HRTs) of 20 to 1.5 d with surface area loading rate (SALR) of 0.86 to 11.43 gCOD/m2/d. Synthetic starch containing desizing wastewater with chemical oxygen demand (COD) of 12.75 g/L was prepared and fed into the reactor. Monod, modified Stover-Kincannon, Grau second-order and First-order substrate removal models were used to evaluate the results of AnMBBR. COD removal efficiency of bioreactor was dwindled by increasing the SALR or reducing the HRT. Decay coefficient (Kd) and yield coefficient (Y) for Monod model were 0.027 1/d and 1.01 mgVSS/mgCOD, respectively. Maximum substrate utilization rate (Umax) and kinetic constant (Kb) for Modified Stover-Kincannon model were estimated as 12.57 and 15.22 g/L/d, respectively. The constants (a and b) for Grau second-order model were found to be 1.09 and 1.31 whilst kinetic coefficient for Second-order model and First-order substrate removal model were 1.62 and 1.55 1/d, respectively. Modified Stover-Kincannon model and Grau second-order model were found to be the best fit for experimental data with R2 value of 0.99. The findings suggest that these models can be applied to predict the behaviour of AnMBBR on various scales.

Rice Straw Hydrolysis and Cultivation of Xanthophyllomyces dendrorhous for Astaxanthin Production and Antioxidant Properties

Astaxanthin is a natural pigment with strong antioxidant activity and is widely supplied as dietary supplement. The red yeast Xanthophyllomyces dendrorhous is one of the potential sources for astaxanthin production. Rice straw was considered for utilization on cultivation and astaxanthin production. Rice straw was treated by autoclave-assisted alkaline pretreatment. and hydrolyzed by cellulase hydrolysis. X. dendrorhous TISTR5730 was cultured and accumulated as the astaxanthin on rice straw hydrolysate. The highest reducing sugar concentration of rice straw hydrolysate was 89.82±0.39g/L (0.71±0.01g/g) when using rice straw (3.3%) and cellulase loading (3 mL). High cell density X. dendrohous TISTR5730 cultivation on rice straw hydrolysate with 20 and 40 g/L of initial reducing sugar was investigated. 40 g/L was appropriate for biomass production while 20 g/L was suitable for astaxanthin accumulation. The highest astaxanthin content was 417.28±50.89 μg/g cell basis at 192 h. Astaxanthin productivity and yield coefficient were 0.01±0.00 mg/L/h and 0.11±0.01 mg/g sugar consumed. The antioxidant activities of astaxanthin were determined by DPPH and ABTS scavenging and FRAP reducing power. The produced astaxanthin represented the high antioxidant activities with IC50 of 9.30 and 1.67 μg/mL of DPPH and ABTS scavenging respectively and FRAP reducing power of 5.31±0.07 μg TEAC/mL. This research indicated that rice straw hydrolysate could be an alternative medium for astaxanthin production. Antioxidant activity of astaxanthin was proved and was feasible for further applications.

Biodegradation of acid red 3BN dye in sequential batch reactor: parameters and kinetics studies

Textile and dye industries generate wastewater which is considered as highly polluted and carcinogenic. Due to this, treatment of wastewater is required earlier to discharge or recycle. In the present studies, treatment of dye bearing water (DBW) has been explored. The treatment was performed using activated sludge (mixed culture) for aerobic process in sequential batch reactor (SBR). The fill volume (V F) and fill time (t F) variation in the treatment of DBW was taken place. The initial value of dye concentration, chemical oxygen demand (COD), sludge, and hydraulic retention time (HRT) were found to play important role in the treatment. At optimum condition (HRT = 2.5 d), the 86.84% COD reduction of 190 mg/L COD, and 92.33% dye reduction of 339 mg/L dye were achieved. These values are equal to overall 94.85% dye reduction of 500 mg/L, and 93.15% COD reduction of 380 mg/L. As a result, 500 mg/L dye was reduced to 26 mg/L, and 380 mg/L COD was reduced to 25 mg/L. The biodegradation fitted to Monod kinetics, for which kinetics parameter values of specific growth rate constant of biomass µ = 0.0047 h−1, yield coefficient (Y) = 1.059, and substrate utilization rate (q) = 0.0044 h−1 were evaluated at HRT = 2.5 d. The results show, this process can be applied to treat Acid Red 3BN Dye Water (AR3BNDW).

Co-metabolic biodegradation of 4-bromophenol in mixture of pollutants system by Arthrobacter chlorophenolicus A6

Brominated phenols are listed as priority pollutants, and are the key components of paper pulp wastewater together with nitrophenol and chlorophenol. However, the biodegradation of bromophenol in a mixed substrate system is very scanty. In the present investigation, simultaneous biodegradation kinetics of three substituted phenols (4-bromophenol, 4-BP; 4-nitrophenol, 4-NP; and 4-chlorophenol, 4-CP) were investigated using Arthrobacter chlorophenolicus A6. A 23 full factorial design was applied with varying 4-BP and 4-CP from 75–125 mgl− 1and4-NP from 50–100 mgl− 1. Almost complete degradation of this mixture of substituted phenols was achieved at an initial concentration combination of 125, 125, and 100 mgl− 1of 4-CP, 4-BP, and 4-NP, respectively in 68 h. Statistical analysis of the results revealed that among the three variables, 4-NP had the most prominent influence on both degradations of 4-CP and 4-BP. While the concentration of 4-CP had a strong negative interaction effect on the biodegradation of 4-NP. Irrespective of the concentration levels of these three substrates, 4-NP was preferentially biodegraded over 4-CP and 4-BP. Further, 4-BP biodegradation rates were found to be higher than that of 4-CP followed by 4-NP. Besides, the variation of biomass yield coefficient of the culture was investigated at different initial concentration combinations of these substituted phenols. Although the actinomycetes consumed 4-NP at a faster rate, the biomass yield was very poor. This revealed that the microbial cells were more stressed when grown on 4-NP compared to 4-BP and 4-CP. Overall, this study revealed the prospective of A. chlorophenolicus A6 for the degradation of 4-BP in mixed substrate systems.

Efficiency of high-carbohydrate fodder in the diets of Holstein cows

Aim: This study aimed to analyze the efficiency of carbohydrate-enriched rations fed to pasture and stall-housed cows. Materials and Methods: Forty Holstein cows were divided into four groups of 10 animals each. The experiment lasted 305 days. All animals were kept under the same conditions, except for the amount of energy-carbohydrate rations fed. The control cows were on a standard diet. Experimental groups 1, 2, and 3 received a ration enriched with energy-carbohydrate components at 250, 500, and 700 g/head/day, respectively. Feed intake was measured on 2 consecutive days each month. During the balance trial, when young animals reached 13 months, feed intake was examined daily. Fodder, its residues, feces, and urine collected during the balance trial were used to determine nutrient digestibility and nitrogen exchange. Results: Nitrogen balance was positive in all experimental animals. Cows in Group 3 made better use of the digested nitrogen. A biochemical blood test showed higher total protein content in the serum of the experimental cows than in the control by 1.47-3.49% (p≤0.05-0.001) in winter and 0.24-0.98% (p≤0.01) in summer. In winter, the serum protein level increased due to changed feeding routines and shorter exercise times, but did not exceed physiological requirements. The alpha- and gamma-globulins levels increased to 0.2-0.5 g/L in winter and 0.3-0.6 g/L in summer, and 0.5-1.4 g/L in winter and 0.1-0.2 g/L in summer, respectively. Beta-globulins decreased. The supplement had a positive effect on milk output, which increased by 67.1-137.3 kg (1.93-3.95%; p≤0.05-0.001) in the first 100 lactation days, then by 198.2-458.8 kg (2.39- 5.53%; p≤0.05-0.001) for the remaining days. All animals had a high milk yield coefficient, with the experimental groups having 0.64-2.64% more milk yield than the control. The lactation curves showed that the average daily milk yield of all experimental cows increased, then gradually decreased along the physiological trajectory from the 3rd month until the end of lactation. Milk quality analysis in the experimental groups indicated an increase in the dry matter content by 0.17- 0.27% (p≤0.001) in summer and 0.16-0.27% (p≤0.001) in winter; higher protein levels by 0.04-0.06% in summer and 0.03- 0.07% (p≤0.05) in winter; increased fat by 0.09-0.14% (p≤0.05-0.001) in summer and 0.09-0.13% (p≤0.05-0.001) in winter; increased density by 0.47-0.61°A (p≤0.05) in summer and 0.17-0.27°A in winter; and increased energy by 1.70-2.63% (p≤0.001) in summer and 1.57-2.54% (p≤0.01-0.001) in winter. Conclusion: The energy-carbohydrate feed "Tanrem" can provide the required energy intake of Holstein cows. The maximum biological and economic effect wads attained at 500 g per animal.