The status of flood wastes treatment and future tasks in South Korea

Natural disasters such as typhoon, flood, and heavy rainfall cause damage in South Korea every year during the summer season. After each rainy season, South Korea suffers not only from flood wastes but also from debris that pile up at dams and stagnate at the estuary of the river. Thus, it is very important to handle these types of wastes as quickly as possible to recover from flood damages and to prevent environmental contamination such as offensive odor and water contamination by the leachate from flood wastes. Other countries such as Japan or USA have established and implemented regulations and guidelines for flood waste. Note, however, that South Korea did not establish practical guidelines; hence, the urgency of establishing practical measures for flood waste. In this study, we suggested various ways of making environmentally sound guidelines including the method of reducing the amount of flood waste by environmentally sound treatment process for flood waste, and the method of setting up and operating the temporary storage site for purposes of efficient separation and treatment of flood waste.     

Preliminary environmental impact assessment of PFOS waste treatment in a lab-scale batch subcritical water decomposition operation

Life cycle assessment (LCA) was carried out by SimaPro 7.3 to study the environmental impact of a lab-scale batch subcritical water decomposition operation for a kilogram of Perfluorooctane sulfonic acid (PFOS) waste treatment in this study, a proven process for the decomposition of PFOS pollutants with high concentration. This LCA focuses on not only the main environmental factors from emissions of toxic pollutants, but also the influence from technical characteristics of the iron-induced subcritical water technology including energy and substances consumption during the subcritical water decomposition treatment process. The IMPACT 2002+ environmental model was used to evaluate the 15 midpoint and 4 end-point environmental damages. It was found that the energy consumption to sustain the high temperature (350 °C) and high pressure (23 MPa) in the subcritical water process contributes 99.8 % of the damages. The total negative impact of the SCWD process for 1 kg of PFOS waste treatment to human health, ecological quality, climate change and resources amounts to 1.11 × 10^?3, 8.43 × 10^?5, 9.76 × 10^?4, 9.05 × 10^?4 Pt, respectively. And the improvement of energy efficiency and catalytic effectiveness are two important factors to reduce the environmental impact from the SCWD process for the treatment of PFOS waste.     

Source Identification and Trends in Concentrations of Gaseous and Fine Particulate Principal Species in Seoul,South Korea

Abstract

Ambient measurements were made using two sets of annular denuder system during the four seasons (April 2001 to February 2002) and were then compared with the results during the period of 1996–1997 to estimate the trends and seasonal variations in concentrations of gaseous and fine particulate matter (PM_2.5) principal species. Annual averages of gaseous HNO₃ and NH₃ increased by 11% and 6%, respectively, compared with those of the previous study, whereas HONO and SO₂ decreased by 11% and 136%, respectively. The PM_2.5 concentration decreased by ～17%, 35% for SO₄ ^2?, and 29% for NH₄ ⁺, whereas NO₃ ^? increased by 21%. Organic carbon (OC) and elemental carbon (EC) were 12.8 and 5.98 μg/m^-3, accounting for ～26 and 12% of PM_2.5 concentration, respectively. The species studied accounted for 84% of PM_2.5 concentration, ranging from 76% in winter to 97% in summer.

Potential source contribution function (PSCF) analysis was used to identify possible source areas affecting air pollution levels at a receptor site in Seoul. High possible source areas in concentrations of PM_2.5, NO₃ ^?, SO₄ ^2?, NH₄ ⁺, and K⁺ were coastal cities of Liaoning province (possibly emissions from oil-fired boilers on ocean liners and fishing vessels and industrial emissions), inland areas of Heibei/Shandong provinces (the highest density areas of agricultural production and population) in China, and typical port cities (Mokpo, Yeosu, and Busan) of South Korea. In the PSCF map for OC, high possible source areas were also coastal cities of Liaoning province and inland areas of Heibei/Shandong provinces in China. In contrast, high possible source areas of EC were highlighted in the south of the Yellow Sea, indicating possible emissions from oil-fired boilers on large ships between South Korea and Southeast Asia. In summary, the PSCF results may suggest that air pollution levels in Seoul are affected considerably by long-range transport from external areas, such as the coastal zone in China and other cities in South Korea, as well as Seoul itself.     

Airborne bacterial reduction by spraying slightly acidic electrolyzed water in a laying-hen house

Spraying slightly acidic electrolyzed water (SAEW) has been considered as a potential approach to reduce airborne bacteria in laying-hen houses. In this study, the effects of spraying SAEW on airborne bacterial reduction were investigated in a laying-hen house as compared with using diluted didecyl dimethyl ammonium bromide (DDAB). Averaged air temperature reduced by approximate 1 °C and average relative humidity increased by 3% at a stable ventilation rate (about 2.5 m³ hr^?1 per bird) in the laying-hen house 30 min after spraying (120 mL m^?2). Compared with the control without spraying, the airborne bacterial concentration was reduced by about 0.70 and 0.37 log₁₀ colony-forming units (CFU) m^?3 in the 4 hr after spraying 120 mL m^?2 SAEW (available chlorine concentration [ACC] of 156 mg L^?1) and diluted DDAB (active compound concentration of 167 mg L^?1), respectively. Compared with spraying diluted DDAB, spraying SAEW was determined to be more effective for reducing airborne bacterial in laying-hen houses. The effects of spraying SAEW and diluted DDAB on airborne bacterial reduction in the laying-hen house increased with the increasing available chlorine concentrations for SAEW (156, 206, 262 mg L^?1) and increasing active compound concentrations for diluted DDAB (167, 333, 500 mg L^?1), respectively. Spraying SAEW and diluted DDAB with two levels of spraying volumes (120 and 90 mL m^?2) both showed significant differences on airborne bacterial reduction in the laying-hen house (P < 0.05).

Implications: It is difficult to effectively reduce airborne bacteria in laying-hen houses. This work describes the application of spraying slightly acidic electrolyzed water as a new approach for reducing airborne bacteria in a laying-hen house. The effects of active compound concentrations and spray volumes on the airborne bacterial reductions by spraying SAEW were also investigated. This study provided a new effective and environmentally friendly approach to reduce the airborne bacteria in poultry houses, contributing to bird housing environment management and improving bird health.     

核桃果皮炭粉对3种重金属离子吸附的影响

采用均匀设计的实验方法,研究了2种核桃果皮炭粉(提取水溶性混合物和未提取水溶性混合物的核桃皮炭粉)对Cr、Cu和Cd等重金属离子的吸附最优条件以及对3种离子吸附的影响因素。结果表明,核桃皮炭粉对Cr(Ⅵ)、Cd2+和Cu2+的吸附最优条件为:pH=4,温度为60℃,浓度为150μg/mL,吸附剂用量为2.4 g,时间为120 min;pH=4.5,温度为30℃,浓度为180μg/mL,吸附剂用量为5.4 g,时间为60 min;pH=5,温度为80℃,浓度为210μg/mL,吸附剂用量为0.4 g,时间为100 min;pH和Cr(Ⅵ)浓度增大,不利于2种吸附剂对Cr(Ⅵ)的吸附;pH和温度增大,不利于2种吸附剂对Cu2+的吸附;温度和吸附剂用量增加,有利于2种吸附剂对Cd2+的吸附。未提取水溶性混合物比提取水溶性混合物的核桃果皮炭粉对3种金属的吸附显著。2种吸附剂的吸附率均表现为Cr>Cd>Cu。     

电解-CPAM联用对印染污泥脱水性能的影响

采用铜-石墨为电极,考察了电解电压、反应时间、极板间距和阳离子型聚丙烯酰胺(CPAM)等因素对印染污泥脱水效果的影响。结果表明,在极板间距为3 cm,电压为15 V,反应时间为40 min时,印染污泥的絮体破解效果最佳。该条件下,添加6.67 mg/g(以污泥干基计,DS)CPAM后,印染污泥的比阻(SRF)、毛细吸水时间(CST)与粘度分别下降了59.30%、41.62%和68.14%,滤饼含水率由89.30%下降至82.08%。扫描电镜结果显示,经过最佳条件处理后,污泥絮体被破坏,减弱了对内部结合水的保持力,使污泥脱水性能得到改善。     

Elevated water temperature reduces the acute toxicity of the widely used herbicide diuron to a green alga, Pseudokirchneriella subcapitata

In the actual environment, temperatures fluctuate drastically through season or global warming and are thought to affects risk of pollutants for aquatic biota; however, there is no report about the effect of water temperature on toxicity of widely used herbicide diuron to fresh water microalgae. The present research investigated inhibitory effect of diuron on growth and photosynthetic activity of a green alga Pseudokirchneriella subcapitata at five different temperatures (10, 15, 20, 25, and 30 °C) for 144 h of exposure. As a result, effective diuron concentrations at which a 50 % decrease in algal growth occurred was increased with increasing water temperature ranging from 9.2 to 20.1 μg L^–1 for 72 h and 9.4–28.5 μg L^–1 for 144 h. The photochemical efficiency of photosystem II (F _v/F _m ratio) was significantly reduced at all temperatures by diuron exposure at 32 μg L^–1 after 72 h. Inhibition rates was significantly increased with decreased water temperature (P?<?0.01). Intracellular H₂O₂ levels as an indicator of oxidative stress were also decreased with increasing temperature in both control and diuron treatment groups and were about 2.5 times higher in diuron treatment groups than that of controls (P?<?0.01). Our results suggest water temperatures may affect the toxicokinetics of diuron in freshwater and should therefore be considered in environmental risk assessment.     

地下水浅埋区某加油站特征污染物空间分布

加油站渗漏污染地下水已经是一个世界性的问题。由于浅埋区加油站储罐与地下水密切接触,更加剧储罐的腐蚀。为揭示加油站渗漏的典型污染物石油烃（TPH）、苯系物（BTEX）、萘和甲基叔丁基醚（MTBE）在该水文地质条件下的迁移变化,在浅埋区某加油站开展了平、枯、丰水期的地下水监测工作。在水平分布上,TPH、BTEX、萘基本相似,均在加油岛附近形成高浓度区,而MTBE则更易随地下水流动而迁移,呈现出不同的污染晕。在垂直分布上,地下水的水位变动是污染物浓度分布的主要影响因素。     

Laccase production by Phomopsis liquidambari B3 cultured with food waste and wheat straw as the main nitrogen and carbon sources

Food waste is the most difficult waste to manage because of the high treatment costs and the risk of environmental contamination. Wheat straw burning has become an increasingly discussed topic in recent years because of the air pollution it causes. However, food waste and wheat straw contain high amounts of nutrient elements; efficient utilization of these wastes can improve the environment by lessening airborne pollutant emission and the amount of waste that must be landfilled. It is well known that use of low-cost and abundant waste materials in microbial fermentations can reduce product costs. We aimed to use these resources while improving laccase production by the endophytic fungus Phomopsis liquidambari B3. We cultured P. liquidambari B3 in medium containing food waste and wheat straw as the main nitrogen and carbon sources, respectively. We optimized the fermentation conditions by response surface methodology (RSM), using a Box–Behnken design for RSM I and a central composite design for RSM II. Optimization resulted in an 11.07-fold (1.98-fold RSM I; 5.59-fold RSM II) increase in laccase yield compared with that before optimization. The model was validated by mathematical evaluations and by comparisons between predicted and experimental values. Under optimized conditions, 53.76% of lignin in wheat straw was degraded. By optimizing fermentation conditions and using multiple bioresources, laccase production by this fungus was increased. These results provide the foundation for future research and for scaled-up laccase production.

Implications:Food waste and wheat straw are waste products, but they could be bioresources if they were managed properly. In this work, we innovatively used a mixture of food waste and wheat straw as a substrate for the novel strain Phomopsis liquidambari B3 to produce laccase. This process, which provided the foundation for the subsequent research and for scaled-up laccase production, offers solutions for both rural and urban pollution problems: that is, it reduces the amount of waste material that needs to be disposed of by burning or dumping, and it also produces a valuable product.