Ce⁴⁺-doped nanometer ZnO powder was synthesized by so-l gel method. The microstructures and properties of the samples were characterized through XRD, UV-Vis and FTIR. The results indicated that the Ce⁴⁺ was successfully incorporated into ZnO, and the diameter of the nanometer was about 10.7nm. It induced the redshifting in the UV-Vis spectra. The photocatalytic activity of the samples was investigated using methylene blue (MB) as the model reaction under irradiation with ultraviolet light. The results showed that the doping of Ce⁴⁺ could increase the photocatalytic activities of ZnO nanopowders and that the best molar ratio of Ce⁴⁺ was n(Ce)/n(Zn) = 0.05, that the surfactant was sodium dodecyl sulfate, and that the nanometer ZnO was calcinated at 550 ℃ for 3 hours. Meanwhile, it inspected the effect of photocatalytic efficiency through the pH of MB, the amount of catalyst, and illumination time. The experimental results revealed that the initial mass concentration of MB was 10 mg/L, that the pH value was 7-8, that the dosage of Ce⁴⁺/ZnO photo-catalyst was 5 g/L, that the UV-irradiation time was 2 h, and that the removal rate of MB reached above 85%. Under the optimized conditions, the degradation rate of real dye wastewater was up to 87.67% and the removal efficiency of COD was 63.5%.

The growing of plants hydroponically is a soilless form of growing in modern day agriculture. It helps to make feed available for animals throughout the season since it is not affected by what is faced by field grown crops. The use of animal waste, that is, their faeces, in the growth of forage was compared with commercial hydroponics solutions as a way of looking for a reduction in the cost incurred in the purchase of commercial hydroponics solutions. The study evaluated the use of organic nutrient solutions (ONS) alongside a standard/commercial nutrient solution in growing crops hydroponically on the growth, dry matter yield, water use efficiency, and chemical composition of hydroponic maize fodder. The ONS used were formulated from the dried faeces of cattle, poultry, rabbits, and swine. The prepared organic nutrient solutions with the control were used in growing the maize seeds for 10 days, and growth, yield, and chemical composition were determined. Results show the highest (196 g) dry matter yield for maize hydroponic fodder irrigated with poultry ONS. Similarly, maize irrigated with poultry ONS was significantly (P < 0.05) higher in CP content, while it was not significantly different from maize irrigated with cattle, swine, and commercial solutions. A lower water use efficiency value (0.19 kg DM/m³) was recorded for maize irrigated with cattle ONS. According to the study, irrigating maize with different organic nutrient solutions produced maize fodder with a higher yield and a similar chemical composition as the commercial nutrient solution. 

This work aimed to evaluate the effects of using three different substrates in the semi-hydroponic culture of lettuce (Lactuca sativa L.) using two different nutrient solutions. A first trial was performed with a nutrient solution rich in macronutrients and micronutrients suitable for lettuce culture, and a second trial with a nutrient solution with pretreated wastewater from effluents of a cheese factory. The experimental design was in randomized blocks with three repetitions and three substrates were used: perlite, coconut fiber, and expanded clay, in both trials. The following parameters were observed: number of leaves, diameter of the cabbage, fresh and dry weight of the aerial part, chlorophyll index and mineral composition of the lettuce. For the first trial, the highest result for the number of leaves (20 leaves), fresh weight (142.0 g) and dry weight (7.2 g) of the aerial part was obtained in the plants growing on perlite. In the second trial, the highest result for the number of leaves (28 leaves), diameter of cabbage (26.7 cm), fresh weight (118.8 g) and dry weight (9.5 g) of the aerial part were achieved by the plants that were grown in coconut fiber. The nutrient solutions were analyzed after each irrigation cycle to verify the possibility of their discharge into the environment. Several parameters were analyzed: pH, conductivity, redox potential, nitrates, nitrites, ammoniacal nitrogen, chlorides, hardness, calcium, phosphates, sodium, potassium, chemical oxygen demand (COD) and magnesium. Ammoniacal nitrogen was found to be the only nutrient that can limits the discharge of nutrient solutions into the environment. It was also proven that the plants, besides obtaining the nutrients necessary for their development in the semi-hydroponic system with the nutrient solution with pre-treated residual water, also functioned as a purification system, allowing the said nutrient solution to be discharged into the environment at the end of each cycle.

Catfish (Pangasianodon hypothalamus) are known in Asia, specifically in Southeast Asia. Currently, this fish has been exported to almost all countries in the world. This research aimed to examine the existing conditions of the solid waste produced, analyze the chemical composition of the waste, and look for alternatives for the policy and economical use of waste in the catfish processing business. Using the survey method, data were gathered through measurement at the research location and laboratory, interviews with business owners, and field observations. Proximate analysis was conducted on pink slime meat, belly fat, bones, and fish innards. Analysis of acid number, saponification number, iodine number, and fat fatty acid was carried out on stomach fat. Meanwhile, amino acid analysis was carried out for pink slime meat. Handling catfish industrial waste has yet to be carried out properly, which causes a foul smell and disturbs the environment. The catfish industry waste’s chemical content (protein, fat, water content, carbohydrates, and fatty acids) (pink slime meat, belly fat, fish bones, and innards) is still relatively applicable. The study processed fish waste into products like instant porridge, analogous fish sago rice, and fish sago noodles. The proximate analysis results of these products show figures that exceed the minimum standards for similar products.