Modeling effects of moisture content and advection on odor causing vocs volatilization from stored swine manure

Abstract

Two models for evaluating the contents and advection of manure moisture on odor causing volatile organic compounds (VOC‐odor) volatilization from stored swine manure were studied for their ability to predict the volatilization rate (indoor air concentration) and cumulative exposure dose: a MJ‐I model and a MJ‐II model. Both models simulating depletion of source contaminant via volatilization and degradation based on an analytical model adapted from the behavior assessment model of Jury et al. In the MJ‐I model, manure moisture movement was negligible, whereas in the MJ‐II model, time‐dependent indoor air concentrations was a function of constant manure moisture contents and steady‐state moisture advection. Predicted indoor air concentrations and inhaled doses for the study VOC‐odors of p‐cresol, toluene, and p‐xylene varied by up to two to three orders of magnitude depending on the manure moisture conditions. The sensitivity analysis of both models suggests that when manure moisture movement exists, simply MJ‐I model is inherently not sufficient to represent a more generally volatilization process, which can even become stringent as moisture content increases. The conclusion illustrates how one needs to include a wide variety of manure moisture values in order to fully assess the complex volatilization mechanisms that are present in a real situation.     

Bacteria additives to the changes in gaseous mass transfer from stored swine manure

Abstract

A bacteria additives treatment experiment in assessing the changes in gaseous mass transfer from stored swine manure is presented. The experiment is tested for ammonia, methane, hydrogen sulfide, and carbon dioxide emission data sampled from pilot swine manure columns and analyzed by GC/MS. The result shows that bacteria additives slightly reduce the methane and carbon dioxide releases, while the same additives do not show any effect on the reduction of ammonia. The hydrogen sulfide contents of stored swine manure continued to be low. Gas concentrations emitted from treated and untreated stored swine manure were: 3.76 and 2.2 ppm for methane, 0.35 and 0.11 ppm for ammonia, and 1000 and 470 ppm for carbon dioxide, respectively. A simple model to estimate gas emission rates is also developed from the viewpoint of two‐film resistance theory. The average emission rates calculated from the model for methane, ammonia, and carbon dioxide are respectively: 0.01, 0.0005, and 13.98 g/min from untreated stored manure; while 0.07, 0.096, and 0.55 g/min from treated manure. The emission model also indicates that for most gaseous pollutants of environmental concern, liquid phase transfer coefficient controls the rate of volatile compounds emitted from stored swine manure and gas phase transfer coefficient has insignificant effect in the calculation of overall mass transfer coefficient.     

Factors controlling groundwater quality in the Yeonjegu District of Busan City,Korea, using the hydrogeochemical processes and fuzzy GIS

The hydrogeochemical processes and fuzzy GIS techniques were used to evaluate the groundwater quality in the Yeonjegu district of Busan Metropolitan City, Korea. The highest concentrations of major ions were mainly related to the local geology. The seawater intrusion into the river water and municipal contaminants were secondary contamination sources of groundwater in the study area. Factor analysis represented the contamination sources of the mineral dissolution of the host rocks and domestic influences. The Gibbs plot exhibited that the major ions were derived from the rock weathering condition. Piper’s trilinear diagram showed that the groundwater quality was classified into five types of CaHCO₃, NaHCO₃, NaCl, CaCl₂, and CaSO₄ types in that order. The ionic relationship and the saturation mineral index of the ions indicated that the evaporation, dissolution, and precipitation processes controlled the groundwater chemistry. The fuzzy GIS map showed that highly contaminated groundwater occurred in the northeastern and the central parts and that the groundwater of medium quality appeared in most parts of the study area. It suggested that the groundwater quality of the study area was influenced by local geology, seawater intrusion, and municipal contaminants. This research clearly demonstrated that the geochemical analyses and fuzzy GIS method were very useful to identify the contaminant sources and the location of good groundwater quality.

     

香港、广州、佛山和北京市政垃圾的成分比较及处理策略

现场采样分析了佛山市市政垃圾的组成和性质,比较了香港,广州,佛山和北京等４个城市市政垃圾的特征。４个城市的市政垃圾的组成和性质差别很大,北京市市政垃圾的煤灰含量很高,而香港的市政垃圾的张纸和塑料所占的百分比最大,根据香港固体废弃物的管理经验,广东省城市市政垃圾的处理方式和《中国二十一世纪仪程》,讨论了中国城市市政垃圾的性质和管理策略。     

Adsorption characteristics of Ni(II) on gamma-type alumina particles and its determination of overall adsorption rate by a differential bed reactor

The adsorption experiment of nickel ion [Ni(II)] on gamma-type alumina by a differential bed reactor in aqueous solutions was investigated to determine the adsorption characteristics and overall adsorption rate. The adsorbed amount increased rapidly with pH from pH 2 to 6 and kept constant over pH 6. The adsorbed amount of Ni(II) increased with temperature from 20 to 50 degrees C. Correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.9268 and 0.9489, respectively, and Freundlich isotherm was more suitable for adsorption on gamma-type alumina than Langmuir isotherm.The overall adsorption rate of Ni(II) on gamma-type alumina at pH 6 by a differential bed rector was determined as follows: r = 68.77Ce(1.61) - 17.60qe(0.36). Al(III) ions in solutions were away from the alumina surface during the adsorption of Ni(II) and Al(III) concentration increased with an increasing Ni(II) adsorbed amount on alumina.     

Removal of toxic ions (chromate, arsenate, and perchlorate) using reverse osmosis, nanofiltration, and ultrafiltration membranes

Rejection characteristics of chromate, arsenate, and perchlorate were examined for one reverse osmosis (RO, LFC-1), two nanofiltration (NF, ESNA, and MX07), and one ultrafiltration (UF and GM) membranes that are commercially available. A bench-scale cross-flow flat-sheet filtration system was employed to determine the toxic ion rejection and the membrane flux. Both model and natural waters were used to prepare chromate, arsenate, and perchlorate solutions (approximately 100 μg L⁻¹ for each anion) in mixtures in the presence of other salts (KCl, K₂SO₄, and CaCl₂); and at varying pH conditions (4, 6, 8, and 10) and solution conductivities (30, 60, and 115 mS m⁻¹). The rejection of target ions by the membranes increases with increasing solution pH due to the increasingly negative membrane charge with synthetic model waters. Cr(VI), As(V), and rejection follows the order LFC-1 (>90%) > MX07 (25–95%)  ESNA (30–90%) > GM (3–47%) at all pH conditions. In contrast, the rejection of target ions by the membranes decreases with increasing solution conductivity due to the decreasingly negative membrane charge. Cr(VI), As(V), and rejection follows the order CaCl₂ < KCl  K₂SO₄ at constant pH and conductivity conditions for the NF and UF membranes tested. For natural waters the LFC-1 RO membrane with a small pore size (0.34 nm) had a significantly greater rejection for those target anions (>90%) excluding (71–74%) than the ESNA NF membrane (11–56%) with a relatively large pore size (0.44 nm), indicating that size exclusion is at least partially responsible for the rejection. The ratio of solute radius (r_i,s) to effective membrane pore radius (r_p) was employed to compare ion rejection. For all of the ions, the rejection is higher than 70% when the r_i,s/r_p ratio is greater than 0.4 for the LFC-1 membrane, while for di-valent ions (, , and ) the rejection (38–56%) is fairly proportional to the r_i,s/r_p ratio (0.32–0.62) for the ESNA membrane.     

Levels of organochlorine pesticides in human milk from central Taiwan

The present study determined the residues of organochlorine pesticides (OCPs) in human milk collected in central Taiwan between December 2000 and November 2001. The OCPs were analyzed by GC/MS for 36 human milk samples from healthy women ranging between 20 and 36 years of age. The predominant OCPs were p,p′-DDE, p,p′-DDT, -CHL, heptachlor epoxide, heptachlor, β-HCH, and γ-HCH, with median levels of 228, 19, 7.4, 4.0, 2.3, 1.2, and 0.8 ng/g lipid, respectively. The residues of OCPs in human milk from central Taiwan were comparable to those described in results from Sweden, the United Kingdom, and Japan, and were significantly lower than those from investigations in Asian countries, including China, Thailand, Indonesia, and Vietnam. Low DDE/DDT ratio (mean = 13.6, SD = 6.54) indicated that residual OCPs in human milk mainly originate from past exposure. A notable decrease in DDT levels (∑ DDT = 333 ng/g lipid) in human milk was found in this study compared to results from the previous two decades (∑ DDT = 3595 ng/g lipid). Hypothetically, the level of -CHL was significantly associated with total TEQ levels in Taiwanese human milk because of the sources of food contaminant, i.e. animal fat. Based on low OCP levels in Taiwanese human milk and low estimated median daily intake of total DDTs for a breastfed infant (1358 ng/kg/day) with the assumption of an infant weighting 4 kg and consuming 699 g milk per day in the first month after birth, the Taiwanese policy of breast-feeding promotion was supported.     

Hong Kong citizens' attitude towards waste recycling and waste minimization measures

In a street survey conducted in Hong Kong, it was found that Hong Kong people generally support waste recycling and minimization measures. The results showed that statistically there are associations between sex, accommodation type, education levels and age on one hand and people's attitude toward some waste recycling and minimization measures on the other. A significant number of the surveyed subjects would feel uneasy during the generation of waste if they knew that the recyclable materials would not be recycled. However, this feeling of uneasiness will lessen considerably if the materials are being recycled. With the feeling of uneasiness being lessened, a deterring factor on consumption was weakened. Thus it is plausible that when recycling is more widely carried out, the actual volume of consumption will increase if the urgency of waste minimization is not widely understood. It was also discovered that in an economically prosperous Hong Kong, people can be more supportive to slightly more expensive green products than in Western countries in recession.     

Modification of mutagenic activity of benzo[a]pyrene by trace elements in the Ames assay

Benzo[a]pyrene (BaP) is one of the most ubiquitous environmental contaminants and exerts potent carcinogenicity and mutagenicity. In the presence of rat liver S9 mix, four trace elements, germanium (Ge), iron (Fe), zinc (Zn), and molybdenium (Mo), were included in the Ames Salmonella microsome/mutagenic assay to test their inhibitory effects on BaP-induced mutations. All trace elements were found to exert an inhibitory effect in tester TA98 and TA100 strains; Fe was the most potent among the elements tested, whereas Zn was weakly inhibitory to prevent mutations. The present findings demonstrate that the antimutagenic potential of trace elements, notably Fe, may be attributed to its modulatory effect on the bioactivation and detoxification processes of BaP.     

Linear alkylbenzenesulfonates (LAS) of an urban stream in Korea

Profiles of alkyl homologues and isomers of LAS were monitored for an urban stream polluted with municipal wastewaters in Korea. Alkylchains of the stream LAS were shorter than commercial standards and higher I/E ratios were associated with lower LAS concentrations. These suggested a partial biodegradation of LAS in the stream. Higher LAS concentrations were observed in the upper stream. LAS levels were at their lowest during summer probably due to high precipitation and faster biodegradation rates. LAS contributed to about 29% of MBAS and could be used to roughly estimate BOD concentration of the stream.