Abstract

INIGUEZ, Gilberto; RODRIGUEZ, Ramón  and  VIRGEN, Gil. COMPOSTAJE DE MATERIAL DE DESCARNE Y AGUAS RESIDUALES DE LA INDUSTRIA DE CURTIDURÍA. Rev. Int. Contam. Ambient [online]. 2006, vol.22, n.3, pp.113-123. ISSN 0188-4999.

In the present work the composting process of fleshing materials from tanneries was studied in two phases. In the first phase, two piles formed with flesh material and agave bagasse were composted during 239 days without any turning. In the second phase of 204 days, piles were turned periodically to facilitate the aeration and irrigation with tap water and wastewater from the tanneries. In both phases piles temperature readings were done and 5 average readings were graphed for each day. At the end of the second phase, the compost was evaluated in a field study determining the yield and quality as well as the incidence of Rhizoctonia solani in potatoes. In the laboratory, compost was also subjected to qualitative bioassays to screen for the presence of toxicity against Eisenia foetida and seedling emergency and relative growth of cucumber seeds was determined. Tannery wastewaters used for irrigation of the composting piles, were evaluated for their toxicity against germinating seeds of radish, clover and cucumber. At the beginning of the composting process, agave bagasse and flesh materials were analyzed for water, dry matter, ash, organic matter, total organic carbon and total Kjeldahl nitrogen content. Compost was analyzed for the same parameters, besides of pH, conductivity, and contents of P, K, Ca, Mg, Na, Zn, Mg, Fe and Cu. Chemical oxygen demand, pH, settleable solids, total nitrogen, total solids, total suspended solids and total dissolved solids were determined in tanneries wastewater. In the first and second composting phase temperatures of 56 °C and 65 °C were reached respectively. In the field study, compost treatment was similar to conventional fertilization treatment. Disease severity caused by R. solani, and quantity and quality of potatoes were also similar (p < 0.05) after compost treatment. The high phytotoxicity and worms death could be more related to the high compost sodium concentrations than to compost maturity. The composting process showed to be a good alternative for treating the flesh materials and improved wastewater management. The obtained final product with its high ash and sodium content should be utilized taking into account the recommendations of an agronomist.

Keywords : composting; leather processing; tanneries.

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