Kristīne Kalneniece, Andrejs Bērziņš, Zaiga Petriņa, Kristīne Ruģele, Elīna Salava, Kārlis Švirksts, Māra Grūbe, Vizma Nikolajeva and Olga Mutere
The aim of this study was to characterize the digestate from an activated sludge biogas reactor (IDARS) as an inoculum for enzymatic hydrolysis and biogas production from organic wastes. Aerobic and anaerobic bacteria are represented in IDARS with H’ index 3.1 and 2.5, respectively. IDARS stimulated the enzymatic hydrolysis of wood and leaves, preferably broadleaf tree species. The results demonstrated the potential of IDARS for improvement of the technological parameters for conversion of organic wastes into biogas.
Jūlija Karasa, Juris Kostjukovs and Solveiga Grinberga
Low cost, effective and water soluble organic coagulant is offered for the extraction of charged clay particles. Coagulation with KOHIDRAC results in simultaneous concentration and purification of the clay fraction. After treatment with KOHIDRAC the obtained clay samples were free of carbonates and feldspar. Moreover, the amount of quartz decreased significantly in finished samples. The proposed coagulant and the patented methodology can be successfully used as purification procedure or as pretreatment for qualitative and quantitative analysis of clay minerals. The possible structure of the active compound KOHIDRAC was investigated in this paper. Real applications of the coagulant were provided.
Ceramic water filters were prepared from different proportions of kaolin and soft wood and sintered at 900 °C, 950 °C, and 1000 °C. The flow rate, conductivity, pH of filtered water and removal efficiency (microbial, water hardness agent’s, nitrite and turbidity) were analysed. The ceramic filter with 15 % saw dust, 80 % clay and 5 % grog that was fired at temperature of 950 °C or 1000 °C showed the best removal efficiency. Statistical ANOVA tests showed a significant difference between ceramic filters with various compositions in their removal efficiencies.
Palusamy Suppuraj, Ganesamoorthy Thirunarayanan, Meenakshisundaram Swaminathan and Inbasekaran Muthuvel
Spinel ZnFe2O4 was developed successfully as a heterogeneous-Fenton catalyst for the degradation of Reactive Yellow 86 (RY 86) under UV light. The ZnFe2O4 was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and UV-diffuse reflectance spectroscopy (UV-DRS). FE-SEM reveals that the some of the particles sizes are in the range from 10 nm to 50 nm. The photocatalytic performance of ZnFe2O4 was evaluated by degradation of RY 86 dye solution under UV light. The degradation rate was highly influenced by pH, initial concentrations of H2O2 and catalyst concentration. The results indicated that ZnFe2O4 could be used as a photocatalyst for treatment of industrial coloured wastewater. The catalyst was reused for five consecutive runs without significant change in its activity. Moreover, the antibacterial effects were investigated.