This research shows a method of elimination of methylene blue from aqueous solutions using raphia fiber. Sorption was applied in a bath system and in the system with mixing and online measurement. The obtained data in equilibrium can suggest adjusting the sorption isotherm model and calculation of the maximum sorption capacities. The Langmuir isotherm model has the highest correlation coefficient R² which shows that the adsorption process of methylene blue on the raphia fibers is a monolayer adsorption process. On the other hand, the Freundlich isotherm is also well fitted, which may indicate that the isotherm is also well adapted, while in the system with mixing and online measurement, the highest matching factor is characterized by the Freundlich isotherm model. The pseudo-second-order rate model is best fit for the sorption kinetics, on basis of which it can be concluded that the sorption rate-limiting step is chemisorption.

Recently there has been an increase in consumption of meat, especially poultry. This results in an increase in the quantity of waste, including waste feathers. Waste from the meat industry are hazardous, which must be disposed of in accordance with the law. Wastes from the meat industry normally consist of valuable elements such as phosphorus, calcium, potassium, magnesium (macronutrients), and iron, copper, zinc, manganese (micronutrients), which after suitable processing can be used for the purposes of fertilization. The paper presents the results of thermal treatment of feathers with meat and bone meal and feathers with poultry litter in a high scale rotary kiln. Mixtures of wastes were incinerated in temperature range from 600 to 900 °C for about 20–25 min. The resulting ashes were characterized by a high content of phosphorus (4–17%), calcium (17–30%) and potassium (0.6–3.6%). The study revealed that the selection of process parameters allows for obtaining ash with controlled and desired composition of macro and micronutrients, moreover, it is safe in terms of sanitary.