Formulation screening and slow release effect evaluation of coated slow release fertilizer made from Baijiu wastewater sludge
A large amount of sludge produced during liquor wastewater treatment not only has relatively low heavy metal content,but also is rich in plant nutrients such as nitrogen,phosphorus,potassium and organic matter such as humic acid,which has outstanding agricultural potential.However,due to its rapid nutrient release,it is easy to cause secondary pollution to the surrounding area.Therefore,in this paper,granulation coating process was used to make liquor wastewater sludge into slow-release fertilizer,and nutrient release rules of untreated sludge(CK1),uncoated sludge(CK2)after granulation and sludge coated with calcium alginate hydrogel(SA),polyvinyl alcohol(PVA)and rosin glycerol(EG)after granulation were analyzed.Fourier transform infrared spectroscopy was used to explore the effects of different coating agents on sludge properties,and the cumulative leaching curves of total nitrogen,total phosphorus and total potassium were fitted with Logistic,Gompertz and Richards models.The results showed that PVA had the least effect on the change of functional groups in sludge,SA significantly increased the content of hydroxyl group in sludge,EG mainly increased the content of ester group in sludge.After granulation,different coating materials all reduced the nutrient release rate of sludge,and SA had the best effect on the controlled release of sludge nutrients,and the cumulative leaching amounts of total nitrogen,total phosphorus and total potassium were the lowest in the experimental group on the 42nd day.The fitting results of different types of models showed that the three models had good fitting effects on nutrient release of sludge,and the Logistic model had the highest fitting degree.The study showed that the granulation coating technology could better reduce the nutrient release rate of liquor wastewater sludge,and the nutrient release rate of sludge after granulation coating was in line with the Logistic model.According to the model,SA had the best effect on nutrient controlled release of sludge,and its maximum release and growth rate of three elements of nitrogen,phosphorus and potassium were the lowest among the five experimental groups.The p values of Logistic model parameters were the highest among the five groups.
liquor wastewater sludgegranulationslow release fertilizercoatingnutrient releaselogistic model
万方数据
维普
