This issue includes 10 papers selected from various fields of environmental engineering including wastewater treatment, air pollution and soil pollution. Alami [1] reviewed the use of rare-earth manganites as catalysts for environmentally essential reactions and suggested that cerium manganite is the most practicable catalyst for technological purposes. Park and Choi [2] wrote about a risk assessment of environmental media such as soil, groundwater, and crops for people in the area of the abandoned Nokdong metal mine. Kim et al. [3] developed a dust collection system equipped with activated carbon coated electrode that appears to be a promising substitute for existing dust-control devices. Choi and Lee [4] evaluated that Chlorella vulgaris can be successfully used to remove ammonia-nitrogen from waste-water. Lee et al. [5] suggested the soil ecological protective concentration of cadmium in Korea using Korean ecological risk assessment methodology. Shirzad-Siboni et al. [6] experimentally showed that the activated red mud obtained from a bauxite mill can be used to treat phenol efficiently with low cost. Lee et al. [7] suggested refined exposure assessment for active ingredients of humidifier disinfectants. Shin and Nishimu [8] evaluated utilization of food sources of Nuttallia olivacea at Gamo Lagoon, Japan before and after the 2011 tsunami. Kim et al. [9] demonstrated that their new synthetic iron-loaded zeolites can be applied as a heterogeneous nutrient-removal materials with no sludge production. Eaktasang et al. [10] reported that a dual-chamber microbial fuel cell inoculated with Desulfovibrio desulfuricans and supplemented with lactate enhanced the current production in the microbial fuel cell as a result of effective attachment of cells, as well as electron transfer among the cell network to the electrode.