Experimental studies on biogas yield of Ulva pertusa were carried out at different fermentation conditions. At 25°C, 35°C and 45°C, the biogas yield from fermentation of Ulva pertusa were 223.2mL/gVS, 256.2mL/gVS and 300.0mL/gVS,respectively, while the methane content in the biogas produced at 35°C was the highest. In addition, biogas yield reached to 482.5mL/gVS and 499.6mL/gVS by adding waste paper of 3.5g and 7.0g to the fermentation liquor, the corresponding methane content in the biogas were 56.0% and 51.2%, respectively. Comparatively, higher biogas yield, methane content and system stability could obtain from Ulva pertusa by adding 3.5g ~ 7.0g of waste paper and fermentation at 35°C.The fermentation process of Ulva pertusa for biogas production generally lasted for 19~25 days.

A leaching solution of white mud was prepared from this waste material of soda production, and used for treatment of waste cutting oil emulsion. In alkaline conditions, the leaching solution of white mud generates hydroxide precipitates, which have relatively high specific surface area and excess surface energy, and readily adsorb the pollutants in waste cutting oil emulsion. The chemical composition of the white mud was determined and the hydroxide precipitates were characterized. The maximum removal efficiency (of turbidity, oil contents and TOC) was obtained at an adsorbent dosage of 4.0 g/L, pH 12.0 and 25°C. Leaching solutions of white mud could be used as an effective and low-cost material for treatment of waste cutting oil emulsion by the precipitation method.