The Study On Relationships Between Physiochemical Characteristics And Bioavailability Of Heavy Metals In Adding Attapulgite Compost

Livestock manure pollution has become a prominent problem of environmental pollution, manure harmless treatment is imperative, thermophilic composting is one of the main livestock manure harmless and resource-oriented. This paper takes the chicken manure as the research object, focusing on the change rule of temperature, p H, electrical conductivity(EC), organic matter, total carbon, water-soluble NH4+-N, NO3--N and other physicochemical properties. Studying on the effect of adding different proportions of attapulgite on the physicochemical properties and compost product quality, and the correlation between various physicochemical properties, and study on the influence of physicochemical properties on the biological effectiveness of heavy metals. The main conclusions through the experiment were as follows:1. At the beginning of the compost, each pile temperature heated up quickly, in the fourth day, each pile temperature basicly reached about 50 ℃. Temperature of compost will remain for a period of time in the high temperature phase, and then began to decline, eventually down to room temperature. This conformed to the composting rotten conditions. Adding different proportions of attapulgite had no obvious effect on pile temperature changes.2. p H will be a trough in the early compost, and later appeared an increasing trend, the final compost presented alkalescence. Adding attapulgite made the final p H stable, the relatively better deal were A15, A12, and A9. EC presented rise, adding different proportions of attapulgite can reduce EC.3. The organic matter and total C presented decreased in the process of composting. Adding different proportions of attapulgite can promote the degradation of organic matter and total C, the best deal was A12.4. The content of NH4+-N was first increased and then decreased. Adding different proportions of attapulgite can reduce the trend decline of NH4+-N content in the late compost, the best deal was A6. The content of NO3--N generally increased in the process of composting. Adding different proportions of attapulgite can improve the trend increase of NO3--N content in all processing, A15 was the best deals. There was a certain downward trend, which may owe to leaching of NO3--N in the late compost.5. Temperature and p H was significantly positively correlated with NH4+-N, egativly correlated with NO3--N. p H was significantly correlated with organic matter and total C at 0.01 levels. Conductivity was significantly egativly correlated with organic matter and total C at 0.01 levels. Organic matter was significantly positively correlated with total C. NH4-N was egativly correlated with NO3--N.6. The physicochemical properties of composting process related to the change of leaching states of heavy metals in different processing, of which the impact of Zn, Cu, and Cr is relatively larger. p H, organic matter and total C was significantly correlated with the leaching states of heavy metals. p H has negative effect on Cu, positivly affected on Zn, Cu, Cr. Organic matter and total C has negative effect on Zn, Cu, Cr, positivly affected on Cu. And the relevance of physicochemical properties with the various leaching states was different.7. The physicochemical properties of composting process related to the change of speciation of heavy metals. EC, organic matter and total C was significantly correlated with the change of speciation of heavy metals. p H was significantly correlated with the change of speciation of heavy metals in A9, and the correlation between physicochemical properties and different speciation of heavy metals was also different.