Phosphorus is a vital resource for sustaining agriculture and nutrition, but a limited non-renewable resource. Thus, the recovery of phosphorus from waste activated sludge(WAS) was attempted by microwave heating and magnesium ammonium phosphorus(MAP) crystallization. Polyphosphate-accumulating organisms(PAOs) in WAS release phosphate from the cell when they are exposed to high temperature environments. Microwave heating caused phosphorus and ammonia to release from WAS. The amount was increased with increasing temperature, showing that 88.5% of polyphosphate present in the cells were released in the form of phosphate at 80oC. A similar result was also observed in the release of ammonia. On the other hand, both phosphorus and ammonia were crystallized with magnesium, and then was harvested as MAP. Phosphorus recovery rate reached almost 97.8%, but the ammonia was about 13.4%. These results cleary indicate that phosphorus could be recovered from WAS using a physiological trait of PAOs. Heavy metal analyses also show that the MAP crystal is useful and safe as a phosphorus fertilizer.

The objective of this study was to find optimum pretreatment conditions of ozone and microwave for solubilizationof thickened waste activated sludge (TWAS). Response surface analysis was applied to determine the combination of ozoneconcentration (0.03 to 0.1g O3/g total solid (TS)) and microwave temperature (100~170oC). The temperature significantlyaffected the solubilization degree of sludge (p<0.01). Within the design boundaries, the conditions predicted to maximizethe solubilization degree of 41.6% were determined to be 0.065g O3/g TS and 170oC. On the other hand, the solubilizationdegree with the ozone pretreatment alone was 2.7 to 12.2% at 0.03~0.1g O3/g TS. The results show that the combinationof ozone and microwave pretreatments is effective in solubilization of TWAS.

The objectives of this research was to evaluate the anaerobic digestibility of waste actizvated sludge (WAS) and wastebeverages in beverages manufacturing industry using BMP test under various conditions. Also, the effects of physical(ultrasonic) and biological (lactobacillus) solubilization process on anaerobic digestibility of WAS were thoroughlystudied. The soluble chemical oxygen demand (SCODCr)/total chemical oxygen demand (TCODCr) ratio of WAS was 0.15but the SCODCr/TCODCr ratio after solubilization was increased 17.5% by ultrasonic, 18.8% by lactobacillus respectively.The results of BMP test, methane gas productivity as mixing ratio of WAS and waste beverages were 156ml CH4/gCODCr,164ml CH4/gCODCr and 182ml CH4/g CODCr, respectively 9:1, 8:2, 7:3 before the solubilization of WAS. As themixing ratio of waste beverages increase, VFAs concentration and methane productivity was increased. Also, methanegas productivity as mixing ratio after the solubilization of WAS using ultrasonic and lactobacillus was increased3.3~11.3%, 11.1~15.2% respectively. From the results, it was judged that anaerobic digestion using WAS and wastebeverages could be feasible.

Waste activated sludge (WAS) and food waste (FW) are available year round at low cost and have the potential to promote synergism in anaerobic digestion (AD). The goal of this study was to clarify the synergism in co-digestion of WAS and FW. A slight amount of FW at various ratios was added to WAS as an auxiliary substrate, and anaerobic batch tests were performed under mesophilic conditions. By adding FW, total CH₄ produced was increased, where most of them were come from WAS, clearly suggesting synergism. Also, lag period was shortened and CH₄ production rate was increased by FW addition. It was hypothesized that enhanced performance was owing to the facilitated hydrolysis of WAS by FW addition, which was revealed by the increased activities of hydrolytic α-amylase and protease.

The biosorption of dye, Rhodamine B(Rh-B), onto waste activated sludge was investigated. The biosorption capacity and contact time were shown as a simulation of dye adsorption equilibrium and kinetics models. We observed that biosorption of Rh-B occurred rapidly less than 4hr. These experimental data could be better fitted by a pseudo-second-order rate equation than a pseudo-first-order rate equation. The equilibrium dependence between biosorption capacity and initial concentration of Rh-B was estimated and it was found that the equilibrium data of biosorption were fitted by four kinds of model such as Langmuir, Freundlich, Redlich- Peterson, and Koble-Corrigan model. The average percentage errors, ε(%), observed between experimental and predicted values by above each model were 21.19%, 9.97%, 10.10% and 11.76%, respectively, indicating that Freundlich and Redlich-Peterson model could be fitted more accrately than other models.

A lot of sludges occur during an activated sludge treatment process of the washing wastewater and by-product waste in the cuttlefish processing manufacture. The sludges give also out a bad smell, and their amicable reclamation is very difficult because of the limited area of the filling-up. To reduce the heavy weight and large volume of the sludges, they was burning up. After the burning up at 350℃ for 2hrs the weight(volume) of the sludges were reduced to 5% level of the initial value. In contents of the bad heavy metals for human after the burning up, cadmium and lead metal were slightly detected, while mercury and the bad others not detected.