Affiliations: Sino-Japanese Friendship Center for Environmental
Protection, Beijing 100029, China | Graduate School of Science & Engineering, Saitama
University, 255 Shimo-ohkubo, Urawa, Saitama 338-8570, Japan | Institute for Environmental Studies of China | Chongqing Environmental Protection Bureau, China
Abstract: The bio-briquette technique which mixes coal, biomass and sulfur
fixation agent and bio-briquettes under 3–5 t/cm^2
line pressure has aroused people's attention in view of controlling the air
pollution and the acid rain. In this paper, the physicochemical properties of
bio-briquette and its ash were investigated. And the acid soil was improved by
the bio-briquette combustion ash, which contained nutritive substances such as
P, N, K and had the acid-neutralizing capacity (ANC). The pH, EC, effective
nutrient elements (Ca, Mg, K, P and N), heavy metal elements (Al, Cu, Cd, Cr,
Zn and Mn) and acid-neutralizing capacity change of ash-added soils within the
range of 0%–10%, were also studied. Specially, when 5% bio-briquette
combustion ash was added to the tested soil, the content of the effective
elements such as Ca, Mg and K rose by 100 times, 7 times and twice,
respectively. The total nitrogen also increased by about twice. The results
showed the oxyanions such as that of Al, Cu, Cd, Cr, Zn and Mn were not
potentially dangerous, because they were about the same as the averages of them
in Chinese soil. It is shown that the ANC became stronger, though the ANC
hardly increases in the ash-added soil. On the basis of the evaluation indices,
it is concluded that the best mixture ratio is to add 2.5%–8% of the
bio-briquette combustion ash to the tested soil.
Keywords: bio-briquette combustion ash, soil improvement, ANC, heavy metal element, nutrient element
