Study on effectiveness of eradicating the indicator bacteria in pig manure by composting method adding urea

Abstract

The study was conducted to assess the current situation of pig manure management in Soc Son, Ha Noi and the effectiveness of eradicating the thermophilic indicator bacteria (E. coli and Enterococcus spp) by composting method, adding urea. This is a suitable, easy, simple waste treatment method for the application of the small scale household farms. The result of surveying 60 pig household farms showed that 85% of the farms treated the animal wastes by biogas system, 1.7% of the farms used animal wastes for fish pond, and the rest used animal wastes for the rice fields and cultivation. Biogas is one of the most common treatment method but majority of the farms having the small biogas tanks, therefore it can not treat properly a large amount of the animal wastes. Two species of E. coli and Enterococcus sp. were monitored for the effectiveness of the traditional waste treatment method. Before treatment, the amount of E. coli in pig manure ranged from 12.6x107 - 66.25x107 (CFU/g) in winter and from 29.2 × 105 - 15.7 × 106 (CFU/g) in summer, while the amount of Enterococcus in pig manure ranged from 15, 4 × 10 4 CFU/g. The composting method adding small amounts of urea (1-1.5%) had completely eliminated the bacteria amount after 15-30 days of composting. The result of measuring temperature and pH of the compost heaps in whole composting duration indicated that the temperature did not increase (30-360C), but pH increased (≥ 8). This may be a factor for eradicating bacteria in the compost heaps.