Effect of loading rate on polymer wear

Overloaded anaerobic treatment systems are characterized by high concentrations of volatile fatty acids and molecular hydrogen and poor conversion of primary substrates to methane. Previous experiments with fixed–film reactors indicated that operation with reduced headspace pressures enhanced anaerobic treatment. For these studies, four suspended culture, anaerobic reactors were operated with headspace pressures maintained between 0.5 and 1.0 atm and a solids retention time of 15 days. For lightly loaded systems (0.4 g SCOD/g VSS-day) vacuum operation provided minor treatment improvements. For shock organic loads, vacuum operation proved to be more stable and to support quicker recovery from upset conditions. Based on these studies and a companion set of bioassay tests, it was concluded that: (a) a loading rate of about 1.0 g SCOD/g VSS-day represents a practical loading limit for successful anaerobic treatment, (b) a headspace pressure of approximately 0.75 atm appears to be an optimum operating pressure for anaerobic systems and (c) simple modification to existing systems may provide relief for organically overloaded systems.

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Dynamic changes in spatial microbial distribution in mixed-population biofilms: experimental results and model simulation

Water Science & Technology ◽

10.2166/wst.1995.0266 ◽

1995 ◽

Vol 32 (8) ◽

pp. 67-74 ◽

Cited By ~ 20

Author(s):

Satoshi Okabe ◽

Kikuko Hirata ◽

Yoshimasa Watanabe

Keyword(s):

Oxygen Diffusion ◽

Loading Rate ◽

Model Simulation ◽

Mixed Population ◽

Experimental Results ◽

Synthetic Wastewater ◽

Diffusion Limitation ◽

Dynamic Changes ◽

Microbial Distribution ◽

Rotating Biological Contactors

Dynamic changes in spatial microbial distribution in mixed-population biofilms were experimentally determined using a microslicer technique and simulated by a biofilm accumulation model (BAM). Experimental results were compared with the model simulation. The biofilms cultured in partially submerged rotating biological contactors (RBC) with synthetic wastewater were used as test materials. Experimental results showed that an increase of substrate loading rate (i.e., organic carbon and NH4-N) resulted in the microbial stratification in the biofilms. Heterotrophs defeated nitrifiers and dominated in the outer biofilm, whereas nitrifiers were diluted out in the outer biofilm and forced into the inner biofilm. At higher organic loading rates, a stronger stratified microbial spatial distribution was observed, which imposed a severe internal oxygen diffusion limitation on nitrifiers and resulted in the deterioration of nitrification efficiency. Model simulations described a general trend of the stratified biofilm structure. However, the actual stratification was stronger than the simulated results. For implication in the reactor design, when the specific carbon loading rate exceeds a certain limit, nitrification will be deteriorated or require a long start-up period due to the interspecies competition resulting in oxygen diffusion limitation. The extend of microbial stratification in the biofilm is especially important for determination of feasibility of nitrification in the presence of organic matters.

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Anaerobic Treatment of Polyethylene Terephthalate (PET) Wastewater from Lab to Full Scale

Water Science & Technology ◽

10.2166/wst.1999.0426 ◽

1999 ◽

Vol 40 (8) ◽

pp. 229-236 ◽

Cited By ~ 4

Author(s):

F. Fdz-Polanco ◽

M. D. Hidalgo ◽

M. Fdz-Polanco ◽

P. A. García Encina

Keyword(s):

Polyethylene Terephthalate ◽

Loading Rate ◽

Treatment Plant ◽

Textile Wastewater ◽

Anaerobic Treatment ◽

Cod Removal ◽

Organic Loading Rate ◽

Foam Formation ◽

Organic Loading ◽

Start Up

In the last decade Polyethylene Terephthalate (PET) production is growing. The wastewater of the “Catalana de Polimers” factory in Barcelona (Spain) has two main streams of similar flow rate, esterification (COD=30,000 mg/l) and textile (COD=4000 mg/l). In order to assess the anaerobic treatment viability, discontinuous and continuous experiments were carried out. Discontinuous biodegradability tests indicated that anaerobic biodegradability was 90 and 75% for esterification and textile wastewater. The textile stream revealed some tendency to foam formation and inhibitory effects. Nutrients, micronutrients and alkali limitations and dosage were determined. A continuous lab-scale UASB reactor was able to treat a mixture of 50% (v) esterification/textile wastewater with stable behaviour at organic loading rate larger than 12 g COD/l.d (0.3 g COD/g VSS.d) with COD removal efficiency greater than 90%. The start-up period was very short and the recuperation after overloading accidents was quite fast, in spite of the wash-out of solids. From the laboratory information an industrial treatment plant was designed and built, during the start-up period COD removal efficiencies larger than 90% and organic loading rate of 0.6 kg COD/kg VSS.d (5 kg COD/m3.d) have been reached.

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Factors affecting phosphorus removal in two biofilter system treating wastewater from car-washing facility

Water Science & Technology ◽

10.2166/wst.2000.0483 ◽

2000 ◽

Vol 41 (4-5) ◽

pp. 487-492 ◽

Cited By ~ 6

Author(s):

D. Pak ◽

W. Chang

Keyword(s):

Phosphorus Removal ◽

Phosphorus Content ◽

Hydraulic Retention Time ◽

Loading Rate ◽

Aerobic Condition ◽

Suspended Solid ◽

Nitrogen Loading ◽

Operational Parameters ◽

Factors Affecting ◽

Biological Filter

A two-biofilter system operated under alternating anaerobic/aerobic conditions was tested to remove nutrient as well as organics from wastewater generated from car-washing facility. The wastewater was characterized by relatively low organic and high phosphorus content. The factors affecting phosphorus removal in the two-biofilter system were investigated. Operational parameters examined in this study were hydraulic retention time, organic, suspended solid and nitrogen loading rate. The factors affecting phosphorus removal in biological filter appeared to be influent COD, COD/T–P, BOD/COD, nitrogen, and SS/T–P. Nitrite and nitrate produced in the biofilter in aerobic condition affected phosphorus removal by the two-biofilter system. The biomass wasted during backwash procedure also affected total phosphorus removal by the system.

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UNDRAINED CYCLIC SHEAR BEHAVIOR OF CLAY UNDER DRASTICALLY CHANGED LOADING RATE

International Journal of Geomate ◽

10.21660/2020.66.07893 ◽

2020 ◽

Vol 18 (66) ◽

Cited By ~ 1

Author(s):

Imran Khan

Keyword(s):

Loading Rate ◽

Shear Behavior ◽

Cyclic Shear

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PEMANFAATAN TANAH VULKANIK DALAM SISTEM MULTIPLE SOIL LAYERING (MSL) TERHADAP PEMURNIAN AIR IRIGASI TERPOLUSI

Jurnal BiBieT ◽

10.22216/jbbt.v2i1.3085 ◽

2017 ◽

Vol 2 (2) ◽

pp. 49

Author(s):

Welly Herman ◽

Darmawan Darmawan ◽

Gusnidar Gusnidar

Keyword(s):

Irrigation Water ◽

Loading Rate ◽

Quality Standard ◽

High Ability ◽

Volcanic Soil ◽

Soil Mixture ◽

Hydraulic Loading Rate ◽

Hydraulic Loading ◽

Soil Layering ◽

Mesh Sieve

The research aimed to make Volcanic soil of Multiple Soil Layering (MSL) with different Hydraulic Loading Rate (HLR) on the purification of polluted irrigation water and to determine the appropriate HLR against purification of polluted irrigation water. The research used an MSL system of the same Soil Mixture Block (SMB) size from a study done by (Chen et al., 2007) arranged in an Acrylic box measuring 50 cm x 10 cm x 60 cm (PxLxT). Making SMB is done by mixing volcanic soil, sawdust, iron, charcoal that has been mashed by 50 mesh sieve, with a combination of 7: 1: 1: 1. The MSL system is supplied with irrigation water taken from the Gunuang Nago irrigation and Pasar Baru area, Cupak Tangah village, Pauh IX sub-district, Padang continuously with different HLR of 250 L/m2/day, 500 L/m2/ day and 1000 L/m2/day. From the result of this research, it is found that MSL system can decrease pollutant content in polluted irrigation water until the concentration below the water quality standard based on PP. 82 of 2001 and MSL system with HLR 250 L/m2/day have high ability in purifying BOD and COD and HLR 1000 L/m2/day has a high ability in purifying NH4+, NO2- and NO3- on polluted irrigation water. Tujuan penelitian ini adalah untuk menentukan pengaruh tanah vulkanik dalam sistem Multiple Soil Layering (MSL) dengan Hydraulic Loading Rate (HLR) yang berbeda terhadap pemurnian air irigasi terpolusi. Penelitian menggunakan sistem MSL dengan ukuran Soil Mixture Block (SMB) yang sama dari penelitian yang telah dilakukan (Chen, Sato, Wakatsuki, & Masunaga, 2007)yang disusun di dalam kotak Acrylic berukuran 50 cm x 10 cm x 60 cm (PxLxT). Soil Mixture Block terdiri dari tanah vulkanik, serbuk gergaji, besi, arang yang telah dihaluskan oleh ayakan 50 mesh, dengan perbandingan kombinasi 7:1:1:1. Sistem MSL dialirkan air irigasi yang diambil dari irigasi Gunuang Nago dan Kawasan Pasar Baru, Kelurahan Cupak Tangah, Kecamatan Pauh IX, Padang secara terus menerus dengan HLR yang berbeda yaitu 250 L/m2/hari, 500 L/m2/hari dan 1000 L/m2/hari. Dari hasil penelitian diperoleh bahwa sistem MSL mampu menurunkan kandungan zat pencemar pada air irigasi terpolusi mencapai kosentrasi di bawah baku mutu air berdasarkan PP No. 82 tahun 2001 dengan HLR 250 L/m2/hari mempunyai kemampuan yang tinggi dalam memurnikan kadar pencemar BOD dan COD sedangkan HLR 1000 L/m2/hari mempunyai kemampuan yang tinggi dalam memurnikan kadar pencemar NH4+, NO2- dan NO3- pada air irigasi terpolusi.

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