MNPs were prepared using coprecipitation method, with FeCl₃, FeCl₂ and ammonia. MNPs were compounded with excess sludge (moisture content of 99%) to prepare magnetic excess sludge (MES). Alternating gradient magnetometer was used to measure the magnetic response of MES and scanning electron microscope (SEM) to observe morphology of excess sludge and MES. After magnetic separation, the water content of MES was calculated to investigate the degree of sludge thickening. The adsorption property of total phosphorus onto MES was investigated. According to the results, MES had superparamagnetism, and its saturation magnetization was 42 emu/g. Within 30 s it could be separated from liquid. The optimal conditions for adsorption of total phosphorus on MES were the initial pH value of solution ranging in 4-6, an initial concentration of phosphorus solution of 16 mg/L (calculated as P), adsorption equilibrium was achieved within 600 min. The kinetics data were fitted well with the pseudo-second order model. The adsorption fitted the Langmuir isotherm well with the equilibrium data and the theoretical maximum adsorption capacity was 3.00 mg/g (calculated as P). MES could accelerate the separation of sludge and wastewater, and the volume of excess sludge was reduced largely. The adsorption performance of total phosphorus on MES was better than that on excess sludge. The study provided a new handling method of excess sludge for sewage treatment plant whose secondary treatment process was activated sludge process.

A solid electrode with Cu(Ⅱ) was prepared by utilizing chitosan modified electrode to adsorb Cu(Ⅱ) in the solution, which was used as the cathode of microbial anode and chitosan modified cathode based battery (MACMCB). Different Cu(Ⅱ) masses and external loadings were tested to study the discharge property of MACMCB system. Results indicate that better discharge process relies on a larger amount of Cu(Ⅱ) or a higher external loading in this work. The highest cell voltage is 0.6346 V. The Cu(Ⅱ) reduction efficiency of MACMCB system is higher than 92.75%, indicating a nearly complete reduction of Cu(Ⅱ). The comparison between MACMCB and MFC indicates that MACMCB showes better performance than MFC on substrate consume and electricity output within a period of time. Changing the solid electrode within 10 - 30 hours is recommended. CuSO₄ is directly adsorbed inside the solid electrode. The major reduction product is copper, while the left included Cu₂O, phosphide of copper and chloride of copper.