Villar L D, Garcia O
Centro Técnico Aeroespacial, Instituto de Aeronáutica e Espaço, Divisão de Química Pça. Mal. Eduardo Gomes, 50, 12228-904 São José dos Campos-SP, Brazil.
Environ Technol. 2003 Dec;24(12):1553-9. doi: 10.1080/09593330309385701.
The effects of metal bioleaching on nutrient solubilization, especially nitrogen and phosphorous, from anaerobically-digested sewage sludge were investigated in this work. The assessment of the sanitary quality of the anaerobic sludge after bioleaching was also carried out by enumerating indicator (total coliforms, fecal coliforms, and fecal streptococci) and total heterotrophic bacteria. The experiments of bioleaching were performed using indigenous sulphur-oxidizing bacteria (Thiobacillus spp.) as inoculum and samples of anaerobically-digested sludge. Nitrogen and phosphorous solubilization from sewage sludge was assessed by measuring, respectively, the concentration of Total Kjeldahl Nitrogen, ammonia, nitrate/nitrite, and soluble and total phosphorous before and after the bioleaching assays. At the end of the experiment, after 4 days of incubation (final pH of 1.4), the following metal solubilization yields were obtained: zinc, 91%; nickel, 87%; copper, 79%; lead, 52%; and chromium, 42%. As a result of sludge acidification, the viable counts of selected indicator bacteria were decreased to below the detection limit (4 x 10(3) cfu 100 ml(-1)), followed by an increase in the mineral fraction of nitrogen (from 6 to 10%) and in the soluble fraction of phosphorous (from 15 to 30%). Although some loss of sludge nutrients can occur during solid-liquid separation following bioleaching, its beneficial effects as metal removal and reduction of pathogenic bacteria are sufficient to consider the potential of this treatment before sludge disposal onto agricultural fields.
本研究考察了金属生物沥浸对厌氧消化污水污泥中养分溶解的影响，特别是对氮和磷的溶解作用。通过对指示菌（总大肠菌群、粪大肠菌群和粪链球菌）以及总异养菌进行计数，对生物沥浸后厌氧污泥的卫生质量进行了评估。生物沥浸实验以本地硫氧化细菌（硫杆菌属）为接种物，以厌氧消化污泥样品为对象展开。通过测量生物沥浸实验前后凯氏定氮法总氮、氨、硝酸盐/亚硝酸盐以及可溶性磷和总磷的浓度，对污水污泥中氮和磷的溶解情况进行了评估。在实验结束时，经过4天的培养（最终pH值为1.4），获得了以下金属溶解率：锌91%；镍87%；铜79%；铅52%；铬42%。由于污泥酸化，选定指示菌的活菌数降至检测限以下（4×10³ cfu 100 ml⁻¹），随后氮的矿物成分比例增加（从6%增至10%），磷的可溶性成分比例增加（从15%增至30%）。尽管生物沥浸后固液分离过程中污泥养分可能会有一些损失，但其在去除金属和减少病原菌方面的有益效果足以使其在污泥用于农田处置之前具备考虑这种处理方法潜力的价值。
