白酒废水污泥制包膜缓释肥配方筛选及其缓释效果评价

Formulation screening and slow release effect evaluation of coated slow release fertilizer made from Baijiu wastewater sludge

白酒废水处理过程中产生的大量污泥(即白酒废水污泥)不仅重金属含量相对较低,而且其中富含氮、磷、钾等植物营养成分及腐殖酸等有机质而具有突出的农用潜力,但因其养分释放过于迅速,容易对周围造成二次污染。为此,利用造粒包膜工艺将白酒废水污泥制作成缓释肥,分析未处理污泥(CK_(1))、造粒后未包膜的污泥(CK_(2))以及造粒后分别用海藻酸钙水凝胶(SA)、聚乙烯醇(PVA)和松香甘油酯(EG)包膜的污泥的养分释放规律,用傅里叶变换红外光谱探究不同材质的包膜剂对污泥性质的影响,并用Logistic、Gompertz和Richards模型进行总氮、总磷、总钾养分累积浸出曲线拟合。研究结果表明,在不同类型包膜材料中PVA对污泥中官能团的改变影响最小,SA则显著提高了污泥中的羟基含量,EG则主要增加了污泥中的酯基含量;造粒后不同包膜材料均降低了污泥的养分释放速率,其中SA对污泥养分的控释效果最好,在第42 d污泥的总氮、总磷和总钾的累积浸出量均为实验组中最低。不同类型模型拟合效果表明:3种模型对污泥的养分释放拟合效果俱佳,其中Logistic模型拟合度最高。该研究表明,造粒包膜技术可较好地降低白酒废水污泥的养分释放速率,同时造粒包膜后污泥的养分释放符合Logistic模型,并且通过模型得知SA对污泥的养分控释效果最好,其氮磷钾3种元素最大释放量和增长速度均为这5组实验组中最低,并且Logistic模型参数p值均为5组中最高。

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(CK_(1)),uncoated sludge(CK_(2))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.