Optimization and Analysis of Liquid Anaerobic Co-Digestion of Agro-Industrial Wastes via Mixture Design

Anaerobic co-digestion (AcoD) is a widely employed technique to produce biogas from simultaneous digestion of various biomasses. However, the selection of the optimal proportions of the substrates in the mixtures presents a challenge. This research used a mixture design to investigate the interactions between the liquid fraction of piglet manure (PM), cow manure (CWM), and starch wastewater (SWW). A modified Gompertz model was used to identify the statistically significant parameters of the methane production curves. The optimal compositions of the mixtures were identified based on multi-objective optimization of the maximal methane yield (YCH4) and maximal methane specific production rate (rCH4) parameters. The study was validated using a double mixture of PM and CWM and a triple mixture. The estimated degradation rates for both mixtures were faster than the predicted ones. The absolute relative errors of rCH4 were 27.41% for the double mixture and 5.59% for the triple mixture, while the relative errors of YCH4 were 4.64% for the double mixture and 10.05% for the triple mixture. These relative errors are within the normal limits of a process with high variability like AD. Thus, mixture design supported by the tested models is suitable for the definition of practically advisable mixtures of substrates.

The assessment of winter wheat agrocenoses adaptivity in the conditions of the submontane zone of the Central Caucasus

The article presents the results of 3 years study on the adaptation of the properties of various winter wheat varieties to the conditions of the submontane zone of the Central Caucasus. The indicator of the ontogenetic adaptability was the homeostaticity of the plants. We have studied thirty winter wheat varieties according to the parameters of ecological plasticity, productivity and resistance to the destructive complex of diseases and pests like Fusarium head blight, brown and yellow rust, Septoria blight, tan spot etc. The yield of the mixed variety crops was 4.5 t/ha; the increase was 9%. In the crops of the triple mixture of the strong Veda and Delta varieties (25%) with the valuable Batko variety (50%), which differed in resistance to various diseases, the average yield of 52 cwt/ha was obtained with the protein content of 12%, the gluten content of 28% and the flour strength of 320 a.u. The authors used the resistance of the precocious Kuma variety to the damage by the cereal leaf beetle as a protective screening crop along with the field perimeter. Such a screening crop of the stable variety prevents the colonization of the crops of the other less resistant varieties with pests. The genetic diversity of the variety creates the conditions for regulating and stabilizing the phytosanitary state of the crops and increasing their productivity. With this agrotechnical method, it becomes possible to regulate and stabilize the phytosanitary situation in the fields and to increase grain productivity and quality.

Comparative Assessment of Single and Joint Toxicity of Bulk and Nano Scale Heavy Metals (Al2O3, CuO and SiO2) Using Haematological Parameters as Biomarker in Juvenile African Catfish (Clarias gariepinus)

Global technological advancement has resulted in the gradual replacement of traditional bulk size compounds with nano-sized ones with diverse useful characteristics. This study is focused on the toxicological assessment of three nano-metallic oxides (SiO2, Al2O3 and CuO) in comparison with their equivalent bulk sizes using African Catfish (Clarias gariepinus). The study involved sub-lethal exposures to binary mixtures of selected ratios (1:1; 2:1 and 1:2) of the respective metallic bulk and nano oxides as well as their triple mixture (1:1:1) for 28 days. The catfishes after 28 days were subsequently subjected to haematological tests (Haemoglobin, Packed Cell Volume, Red blood cells, Platelets, Neutrophils, Lymphocytes, Mean cellular volume, Mean Cell haemoglobin, and Mean Cell haemoglobin Concentration). The results of the haematological assessment indicated that most of the nano-sized oxides showed no significant difference (P>0.05) compared to control whereas the bulk sizes either showed no difference or decrease in the count compared to control. In most of the binary mixtures, catfishes exposed to bulk sizes had lower levels of the haematological parameters but there was no overall trend. The introduction of nanoscale metallic oxides into production activities should be with caution since they may have a similar mode of toxicity to the existing bulk sizes.

Round Table Discussion

Four monthly doses of an alum-precipitated mixture of diphtheria toxoid and H. pertussis vaccine administered after the third or fourth month of life should confer immunity to diphtheria and pertussis. Three monthly or bimonthly doses of an alum-precipitated "triple" mixture of diphtheria toxoid, H. pertussis vaccine, and tetanus toxoid administered after the sixth month of life should confer immunity to diphtheria, pertussis, and tetanus. Alternate gluteal regions are the sites of choice for alum-precipitated antigens in children under three years. When performed three months or more after the final dose of mixed alum-precipitated antigens the positive pertussis agglutinogen skin test and the negative Schick test for diphtheria were adequate evidence of immunity. Before a previously immunized child attends kindergarten or school, one stimulating dose of alum-precipitated mixed antigen is recommended. Probable exposure to a disease of a previously immunized child warrants very prompt administration of one stimulating dose of the respective fluid antigen.