Steroid oestrogens (SE) are released by humans and animals into the environment. In the Mekong Delta animal excrement is directly discharged into surface water and can pollute the water. Only a few animal production sites are currently treating the excrement in either biogas plants or vermicomposting systems. The concentration of SE in manures from pigs and cattle was monitored in the Mekong Delta, Vietnam. Fresh cow faeces had an oestrogen concentration of 3.3 ng E2 eq/g dry weight. The SE concentration in effluent from biogas plants fed with animal manures was 341 ng E2 eq/L. Most of the SE were in the solid phase (77.9-98.7%). Vermicomposting reduced SE to 95% of the original input.

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This research presents the effect of heat treatment temperature on the forming ability of β-tricalcium phosphate (β-TCP) bioceramic materials toward the bone tissue regeneration application. Ca(OH)2 and H3PO4 were mixed with a Ca/P molar ratio of 1.5, followed by hydrothermal treatment at 180oC for 24 hours to obtain the calcium phosphate hydrate (CPH) with phase composition similar to hydroxyapatite (HA). The CPH mineral was heat-treated at 700 and 1000oC for 3 hours to evaluate the ability to obtain β-TCP. The result showed that β-TCP can be obtained by the CPH calcined at 1000oC for 3 hours, with the particle size of 1~2 μm, suitable for bone tissue regeneration application.