Abstract

FRANCISCO ATENCIO, Jenny; RAMOS MATIAS, Pedro  and  AGUIRRE YATO, Guillermo. Potential use in agriculture of sewage sludge from Puente Piedra's waste water treatment plant - Lima. Rev. Soc. Quím. Perú [online]. 2011, vol.77, n.1, pp.66-74. ISSN 1810-634X.

Previous tests of fertilization in pots under greenhouse conditions applied in several rates of sewage sludge generated in Puente Piedra's wastewater treatment plant were conducted with the objective to evaluate the potential agricultural use. Completely randomized design - DCA was applied. The analysis of variance of the average - ANVA, and Tukey comparison test (p<0,05) to evaluate the agronomic variables such as the number of emerging seedlings (s), stem length (H), stem thickness (D) and dry matter (F_f) of maize as indicator plant, were used with this statistic method. Test Nº 1 contained dry sludge in rates 0, 2, 4, 6, 8 and 10% mixed with washed sand, whereas, test Nº 2 contained composted sludge in rates 0, 25, 50, 75 and 100% mixed with washed sand. Also control with NPK inorganic fertilizer (300-400-200) ppm in both tests. Highly significant difference of the measured variables, at higher rates of dried or composted sewage sludge respectively was observed. The emergency showed died of seedlings in both assays. It was attributed to slightly higher salinity of sludge, because it generally inhibits the normal growth of seedlings. Moreover, the slowly mineralization processes in sludge affected the nutrients uptake by plants. The heavy metals concentrations, As, Hg, Pb, Cd and Cr, in sewage sludge, in the soil before and after fertilization and the plant, were evaluated through mean statistic and standard deviation using the Univariate Technic SAS v8. None of the metal concentration in soil, except Pb and Cr after fertilization, in both tests, exceeded comparable with concentration limits make land application of sludge identified by Title 40CFR Part 503. The study demonstrates that dry sewage sludge and composted sewage sludge can be beneficially reused at low rates to produce biosolid providing a long-term sustainable waste management solution for final deposition.

Keywords : sludge of PTAR; heavy metals in sludge; agricultural use; experimental design; bio-statistical analysis; agronomic variable.

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