ISSN:1061-4303    

DOI:10.2175/WER.64.1.15

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

ISSN:1061-4303    

DOI:10.2175/WER.64.1.1

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

ISSN:1061-4303    

DOI:10.2175/WER.64.1.11

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

ISSN:1061-4303    

DOI:10.2175/WER.64.1.12

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Cementitious material was prepared in the laboratory from a mixture of dewatered sludge and lime incinerated at high temperature. The effects of mixture compositions, burning temperatures and durations on chemical and physical properties, and compressive strengths of the material were examined. The effect of curing conditions on compressive strengths was also investigated. From the results, an optimum condition on the mixture composition, burning temperature and duration, and curing condition on the highest possible strength of the material was determined. The experimental results revealed that sludge could be used to produce cementlike material that would satisfy the strength requirements in the ASTM standard for masonry cement. However, the cement is found to be quick setting and exhibits high water demand. The results on chemical analysis, physical properties, and compressive strengths of the material are presented.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.2

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Odor control has been an important component of the operation of the Montgomery County Regional Composting Facility. After several facility improvements, which greatly reduced off‐site odors, the discharge of compost process air remained the greatest source of odor impacts on the surrounding community. Thus, the WSSC assembled a research team to investigate methods of improving odor control treatment for the process air. The research team developed bench‐scale tests and gas chromatographic methods that provided a better understanding of the chemical basis for odor control. Organic sulfur‐containing compounds, especially dimethyl disulfide, were identified as the primary odorants in the process air. Effective removal of the reduced organic sulfides requires oxidation by sodium hypochlorite at a neutral pH. Ammonia interferes with this oxidation process and must be removed to allow effective and reliable oxidation. Hydrogen peroxide has also been used to improve oxidation and reduce chlorine odors. The removal of organic compounds has been enhanced by the use of surfactants. These findings have resulted in further full‐scale improvements to the existing compost process air scrubbing system.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.3

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
VOC emissions from an aerated static pile composting operation are identified and quantified. The most significant odorous VOCs are dimethyl disulfide, dimethyl sulfide, limonene, and alpha‐pinene. A comparison of data from several compost facilities reveals that these compounds are typical but tend to occur in higher concentrations when raw sludge is composted. Active compost exhaust treatment was investigated by bench‐scale testing a packed tower scrubber with various chemicals and three types of adsorbent media. Scrubbing chemicals included sulfuric acid, sodium hydroxide, sodium hypochlorite, hydrogen peroxide, potassium permanganate, DeAmine (by Nutech), and a surfactant. Adsorbent media included virgin activated carbon, caustic impregnated carbon, and a biofilter composed of finished compost. The best results were obtained with a two‐stage packed tower scrubber using acid in stage 1, followed by caustic and hypochlorite at pH 10 in stage 2.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.4

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Past experience has shown that restoration of an aquifer to drinking water quality by groundwater extraction and surface treatment may require many years of pumping. In this research, a mathematical model of hydrocarbon dissolution is developed to aid in the evaluation of groundwater remediation systems. The model assumes that residual hydrocarbon is distributed between two fractions: (1) a fast fraction in equilibrium with the aqueous phase and (2) a slow fraction in which mass transfer is limited. Relationships for simulating equilibrium partitioning are based on classical liquid‐liquid equilibrium theory. Column experiments were performed to test the model and examine the kinetics of aromatic hydrocarbon dissolution as residual hydrocarbon ages. The hydrocarbon dissolution process included an initial equilibrium period during which dissolved hydrocarbon concentrations were high and roughly constant followed by a rapid drop‐off period and an asymptotic period during which dissolved hydrocarbon concentrations were low and declined slowly. After passing more than 700 pore volumes of water through the column, between 8 and 10% of the original toluene and xylene isomers remained in the column. Model simulations were conducted to evaluate the effect of pulsed pumping on groundwater cleanup time.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.5

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Bench‐scale activated sludge experiments were conducted on Sacramento, California, primary effluent to determine the effect of various process control factors onNocardiapopulations in activated sludge. It was possible to washNocardiaout from activated sludge at a sufficiently low MCRT. The washout MCRT for bench‐and full‐scale activated sludge plants was related to the temperature by the Arrhenius equation. Foam trapping was shown to be a major factor in increasingNocardiapopulations in activated sludge. The optimum pH forNocardiagrowth in activated sludge was approximately 6.5. Aerobic selectors were effective in controllingNocardiaat an MCRT of 5 days but not at an MCRT of 10 days. Anoxic selectors controlledNocardiain a nitrifying activated sludge at an MCRT of 12 days.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.6

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
A new technique for measuring the ζ‐potential of organic sludge floe formed by cationic polyelectrolyte addition was devised to efucidate the flocculation mechanism. The ζ‐potential was calculated from the generated electric potentials and the pressure drop formed by forcing the flow of an electrolyte solution over the surface of flat samples. The flat samples were made by compressive dewatering of flocculated sludge. The results obtained were considered to correspond to the potential of the Hoc surface. The ζ‐potential of flocculated sludge samples changed in sign from negative to positive with an increase in the amount canonic polyelectrolyte. The cationic polyelectrolyte dosage whereby the ζ‐potential becomes zero and the optimum dosage at which the de‐watering of flocculated sludge attains a maximum coincided. Because the repulsive force between particles decreases at that dosage (that is, at the break point) owing to the neutralization of the electric charge of particle surfaces, particles approach one another and a floe with good dewatering characteristics is produced.

ISSN:1061-4303    

DOI:10.2175/WER.64.1.7

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY