No abstract

This study looked at how to establish effluent limitation standards for formaldehyde, a toxic chemical widely used in industries. To this end, we reviewed Water Quality Based Effluent Limitation (WQBEL), Technology Based Effluent Limitation (TBEL), and water quality criteria for protection of human health and aquatic organism. Based on the results, we estimated formaldehyde effluent limitation standards appropriate to control water quality of industrial wastewater in Korea. However, this study has limits due to the lack of some data necessary in estimating formaldehyde effluent limitation. For example, although water quality criteria based on non-carcinogenic properties of formaldehyde were calculated, those based on carcinogenic properties were not be able to estimate because of the absence of applicable cancer potency factor q1. Without applicable factor, we calculated water quality standards for formaldehyde based on water quality criteria of advanced countries including the United States, while with no water quality standard we referred to applicable drinking water quality standards of other countries.For eco-toxicity based on water quality criteria, proper figures could not be calculated since there have been few reliable data.

No abstract

Biogas, one of renewable energies, is a key element necessary for a carbon-neutral policy and to build a hydrogen economy. In order to utilize biogas, impurities of biogas such as moisture, hydrogen sulfide(H2S), siloxanes, and VOCs should be removed. In particular, since H2S causes corrosiveness of equipment by sulfur oxides, and is harmful to the human body if leaked, it is a major target material to be removed. The minimum concentration of H2S obtainable from the wet method is several ppm. It is known, however that the iron hydroxide-based adsorbent in the dry method can obtain ultimately low concentration of H2S down to 0.1 ppm or less. The DeHyS was manufactured through a series of processes such as mixing iron cloride solution or iron sulfate solution, NaOH solution, and inorganic binder. During the adsorption process, H2S was removed in the form of iron sulfide through a chemical reaction, and siloxanes are known to be removed through physical adsorption. It was also applied to various biogas plant sites such as landfill gas, sewage sludge, livestock manure, and food waste. At this time, the H2S removal efficiency was known to be 99.9% or more, while simultaneous removal of 90% or more of the total siloxanes was possible. Moreover, the biogas produced at the Chungju Food Bioenergy Center was pretreated using the DeHyS and supplied to the nearby Chungju Bio Green Hydrogen Charging Station to produce hydrogen through steam methane reforming(SMR), producing 500 kg of hydrogen from 8,000 m3 of biogas per day.