Multistaged Anaerobic Sludge Digestion Processes

Two multistaged anaerobic digestion systems, a four-stage thermophilic anaerobic digestion (4TAD), all at 55°C, and a four-stage anaerobic digestion with a tapered temperature configuration (4ADT) at 55, 49, 43, and 37°C, respectively, were studied to evaluate their solids, volatile organic sulfur compounds, and indicator organism (E. coli and fecal coliform) reduction potentials. The 4TAD system removed significantly more volatile solids from sludges than the 4ADT system (6%). However, the dewatered biosolids cakes from the 4ADT system generated fewer organic sulfur compounds than those from the 4TAD system. Both multistage systems showed better digestion efficiencies than single-stage mesophilic or single-stage thermophilic anaerobic digesters at the same overall retention time. However, the lowest organic sulfur compounds were observed from the single mesophilic system. Both multistage anaerobic digestion systems failed to dramatically remove DNA of the indicator organism, E. coli, quantified by real time polymerase chain reaction, even though the indicator organism densities measured by standard culturing methods satisfied EPA Class A biosolids requirements.     

鄂尔多斯盆地小南沟区长6^1储层特征及控制因素分析

通过研究区内大量岩心铸体薄片及物性等资料分析,对小南沟区延长组主要产油层组长6^1储集层的岩石学特征、物性特征及孔隙类型等进行了研究,分析了储层特征及其影响储层储集性能的主要控制因素。结果表明,三角洲前缘亚相沉积的长6^1储集层具有结构成熟度高而成分成熟度低的岩石学特征．主要孔隙类型为原生粒间孔和次生孔隙,沉积环境、成岩作用是影响该区储集层物性的主要因素。     

Sorption of Tertiary Butyl Mercaptan to Indoor Materials in Contact with Air or Water

This study reports sorption of the malodorant 2-methyl-2-propanethiol, commonly known as tertiary butyl mercaptan (TBM), to selected indoor materials. The phase distribution of TBM in gas-solid and aqueous-solid systems was evaluated using batch reactors. Sorbents used in the study included two carpets, two wallpapers, a soil, and granular activated carbon (GAC). Sorption was studied for gaseous and aqueous TBM concentrations spanning three orders of magnitude and contact times ranging from 1 to 28 days. The phase distribution data were plotted and fitted using linear and Freundlich relationships. Results indicated that all solids sorbed environmentally significant quantities of TBM, with the likelihood of producing concentrations above the odor threshold during subsequent remediation using mechanical ventilation. TBM retention by sorbents was greater from air than from water. The malodorant partitioned readily into wallpapers and slowly into the carpet materials. Sorption was nonlinear in the case of GAC and the nonlinearity appeared to increase with sorption contact time. GAC sorbed TBM strongly from both air and water.     

Statistical Modeling to Forecast Odor Levels of Biosolids Applied to Reuse Sites

Proper use or disposal of wastewater solids is an important responsibility of wastewater treatment plants. At present, there are several options for wastewater solids, including agriculture, forestry, and mine reclamation reuse; production of marketable products such as compost and dried pellets; and disposal in landfills and incinerators. Land application of biosolids products is beneficial as part of recycling efforts on local farms, forests, tree farms, and mines and has gained greater acceptance of late. Coupled with these beneficial aspects are odors, which must be managed relative to the receiving populations. In this paper we present several statistical models that predict biosolids odor levels based on processing and management variables as well as ambient conditions. Such models are useful to managers at advanced wastewater treatment plants in helping them to better forecast the biosolids odors and minimize the “odor footprint,” thus making these biosolids products better received.     

Modeling Ventilation Phenomenon in Sanitary Sewer Systems: A System Theoretic Approach

Municipal wastewater collection systems, due to the nature of their functions, carry varying concentrations of odorous gases. The production rate and transport of these gases within and out of sewer systems depend on air flow rate in the system piping. However, municipal sewers are generally designed to only transport sewage flow without giving consideration to the air flow field. As a consequence, the movement of air into, along, and out of collection systems is for the most part uncontrolled. The purpose of this paper therefore is to provide a new design protocol based on system theoretic techniques to be used by municipal engineers and environmentalists involved in odor control and sewer foul air transport studies. The modeling formulation accounts for combined wastewater drag and pressure-induced air flows, and manhole pressurization. The developed framework is applied to both hypothetical and real sewer systems to only illustrate the applicability of the modeling formulation.     

固相微萃取与气质联用法分析鱼肉中气味成分

本文采用固相微萃取技术萃取鱼肉中的挥发性成分,并通过气相色谱质谱联用法来分析、鉴定鱼肉中的气味成分。经NIST质谱数据库检索和文献对照,共检出25种成分,确定20种成分,其中以羰基化合物和醇类为主。相对含量比较多的有1-辛烯-3醇、2,5-辛二酮、2,4-己二烯醇、2-壬烯醇等。     

鄂尔多斯盆地富县探区西南部长6浊积岩储层特征及控制因素分析

通过研究区内大量岩心铸体薄片及物性等资料分析,对富县地区西南部延长组主要产油层组长6储集层的岩石学特征、物性特征及孔隙类型等进行了研究,分析了储层特征及其影响储层储集性能的主要控制因素.结果表明:研究区延长组长6储层为三角洲前缘滑塌浊积岩,岩性以浅灰色、灰色中～厚层细粒长石砂岩为主,含少量岩屑质长石砂岩,岩石学特征相似.孔隙类型以粒间孔、长石溶孔、岩屑溶孔和微裂隙为主.沉积环境、成岩作用是影响该区储集层物性的主要因素.     

Commercial Odor-Reducing Agents for Minimizing the Odor Potential of Asphalt Binders

Odors arising from hot mix asphalt (HMA) production and application are a serious problem due to the proximity of HMA production to human habitation. One possible solution to this problem is the use of odor-reducing agents, which are intended to suppress the production of malodorous compounds. In this study, the ability of seven odor-reducing agents to reduce the odor compounds produced by 22 different HMA binders was quantified. Some odor-reducing agents produced only modest reductions in odors and were inconsistent in performance. Results indicate that terpine and essential oil based odor reducing agents did not appear to be effective in reducing odors. The aldehyde based agents attained the highest degree of odor reduction and appeared to be the most consistent performer over the spectrum of asphalt binders tested. Aldehydes produced reductions in odor potential that consistently exceeded 50% in odor-related volatile organic compounds. The odor reduction seen with the aldehydes is similar to those obtained with a nitrogen purge, leading to the hypothesis that these type of agents act as an oxygen scavenger.     

The influence of stimulus concentration and odor intensity on relaxing and stimulating perceived properties of odors

It is generally assumed that intensity can be used as a proxy of the arousing properties of odors: the more concentrated an odorant, the more intense an odor and the more stimulating and the less relaxing the odor. The aim of the present study was thus to investigate the relationship between relaxing and stimulating properties of odors when judged on two independent scales, for different levels of stimulus concentration. Thirty-three volunteers judged relaxing, stimulating, pleasantness, familiarity and intensity properties of four odors, namely strawberry, lavender, coffee, and lemon, at five concentrations. Our findings show that for all odors, higher stimulus concentration was associated with higher perceived intensity and higher stimulating judgments whereas it was not associated with lower relaxing judgments. On the contrary, lavender and strawberry were also judged more relaxing when stimulus concentration increased whereas coffee and lemon relaxing properties remained the same overall whatever the concentration. Odor familiarity increased with stimuli concentration as well as pleasantness (with the exception of coffee odor). Our results underline the need to use two separate unipolar scales when assessing the relaxing and stimulating properties of odors in self-report questionnaires. They also question the suitability of the commonly used bidimensional framework (valence vs. arousal) to describe olfactory emotions.     

Development and Evaluation of a Copolymer for Removal of Taste and Odor Causing Compounds from Lake Michigan Water

In this study, a copolymer, cyclodextrin/epichlorohydrin was synthesized and used as an adsorbent to remove two taste and odor causing compounds, namely, MIB and geosmin from the Lake Michigan water. The removal efficiency of these compounds using the copolymer on average was 74.5% for MIB and 77.5% for geosmin as compared to the removal efficiency using powdered activated carbon that resulted in 52.9% and 67% removal, respectively, for the same compounds. The removal efficiencies were examined for an initial concentration range of 20 to 120?μg/L for both MIB and geosmin.