El vermicomposteo de biosólidos y agua tratada en el noroeste de México. Ecoparque, un caso de estudio

Abstract

This survey was based on the vermicomposting of cattle manure and sewage sludges using the earthworm Eisenia foetida. Experimental trials were undertaken humidifying biosolids during the process of vermicomposting with wastewater effluent of Ecoparque, the municipal wastewater plant from Tijuana BC (Mexico). Comparisons were performed with vermicomposting using tap water. The obtained results on population growth, protein content and fat of E. foetida were correlated with the yield and chemical composition of the produced compost. Higher figures in worm number and weight were obtained in the experimental units containing sludges humidified with wastewater effluent. Total protein level in the worms varied according with the type of biosolid and water source, high values were obtained in the reactors containing sewage sludge, the obtained figures in this reactors accounted 64.79 % and 61.92 %, while in manure containing reactors the values were 29.64 % and 48.73 % respectively. The obtained figures on E. foetida biomass production and compost composition place vermicomposting as an effective alternative for the treatment, management and recycling of municipal biosolids and wastewaters. Hence, the reduction in biosolids volume and production of nutrients can generate valuable products for animal food and fertilizer for agriculture while reducing environmental damage. Both biosolids meets official standards of the Mexican Official Nom and do not represent any risk to the human health.