Membrane thickening of water works sludge

2001 ◽  
Vol 1 (5-6) ◽  
pp. 215-220
Author(s):  
A. Gillighan ◽  
S.J. Judd ◽  
R. Eyres
Keyword(s):  
Hydraulic Resistance ◽  
Reasonable Agreement ◽  
Chemical Cleaning ◽  
Solids Concentration ◽  
Significant Difference ◽  
Layer Resistance ◽  
Tubular Membranes ◽  
Resistance Data ◽  
Mechanical Cleaning ◽  
Dynamic Layer

The efficacy of ultrafiltration (UF) and microfiltration (MF) membranes was assessed for the concentration of actual waterworks sludges using crossflow tubular membranes operated at constant trans-membrane pressure. The MF membrane gave higher initial fluxes than the UF membrane but after 10 min of filtration the flux value and its decline tended to be very similar for both membranes operating under the same conditions. All membranes gave permeate product water of <0.2 NTU and <100ppb coagulant at all times. For both membranes mechanical cleaning, with sponge balls, was at least as effective as acid chemical cleaning, indicating that no significant permanent internal fouling occurred for these membrane materials. Hydraulic resistance data indicated a significant difference in the dynamic layer resistance between the two membranes. Whilst the UF membrane had a hydraulic resistance 3.7 times that of the MF membrane, the dynamic layer formed on the UF membrane during operation displayed a maximum hydraulic resistance almost nine times lower than that of the MF membrane operating under the same conditions. Correlation of cake resistance R versus feed solids concentration C for all the data generated for t>0 demonstrated reasonable agreement with the expression R∝ca where a=0.37 in the current study. This trend has been recorded in previous reported studies, a varying between 0.33 and 0.62 depending on sludge dewaterability.

The role of fouling mechanisms in a membrane bioreactor

2007 ◽  
Vol 55 (8-9) ◽  
pp. 455-464 ◽  
Author(s):  
G. Di Bella ◽  
F. Durante ◽  
M. Torregrossa ◽  
G. Viviani ◽  
P. Mercurio ◽  
...  
Keyword(s):  
Hollow Fibre ◽  
Chemical Cleaning ◽  
Deposition Mechanism ◽  
Pore Blocking ◽  
Solids Concentration ◽  
Aeration System ◽  
Start Up ◽  
Cake Layer ◽  
Raw Wastewater

The present study has aimed to quantify the role of pore blocking and cake layer in a laboratory scale hollow fibre membrane module in submerged configuration. The membrane reactor (MBR) was fed with raw wastewater, only screened with a 2-mm sieve, collected from the Palermo WWTP. The MBR was characterised by an operating volume of 190 L and equipped with an aeration system located on the bottom of the reactor. The MBR operated for 65 days. The permeate was extracted by imposing a constant flux through the membrane (21 Lh−1m−2). The results confirm the importance of pore blocking control during start-up. In particular, it provides a rapid irreversible fouling that takes place at the beginning of the filtration process, before the deposition mechanism. Therefore, low suspended solids concentration in the initial phase causes a fast irreversible fouling. This circumstance creates the need for more frequent chemical cleaning after start-up without inoculum. Finally, the results underline that the cake has a mainly reversible feature.

Feed intake of grazing cattle. IV. A study with milk cows of the influence of pasture restriction combined with supplementary feeding on production per animal and per acre

1966 ◽  
Vol 8 (1) ◽  
pp. 47-57 ◽  
Author(s):  
W. Holmes ◽  
J. G. W. Jones ◽  
C. Adeline
Keyword(s):  
Feed Intake ◽  
Reasonable Agreement ◽  
Close Agreement ◽  
Live Weight ◽  
Grazing Cattle ◽  
Electric Fence ◽  
Significant Difference ◽  
Milk Cows ◽  
Index Methods ◽  
Pasture Area

The possibility that restriction of pasture and controlled supplementation of the diet of milking cows with concentrates might improve the efficiency of utilisation of grazing was examined in a double reversal grazing experiment with 9 Ayrshire cows per treatment which extended over 4 months.Cows received either pasture alone allocated daily by electric fence (treatment B), or half the pasture area plus one-third of their expected DOM intake offered as concentrates (treatment A).In the first two periods, treatment A resulted in closer defoliation of the pasture.Over the whole experiment there was no significant difference in yield of fat-corrected milk between treatments, although treatment A depressed butterfat percentage and raised milk yield significantly. Treatments did not influence live-weight gain significantly and toth groups gained over the season.Feed intake estimated by chromic oxide-faecal index methods was similar for both treatments except in period 1. Intake estimates by clipping methods or by faecal index methods were in close agreement in period 1 for treatment B and in reasonable agreement in periods 2 and 3.The results are discussed particularly with a view to the possibilities of replacing some grazing with barley or other concentrated feeds. On the available evidence this is economically feasible only where very profitable uses of the grassland saved are possible.

scholarly journals Yield and Fruit Quality Traits of Rambutan Cultivars Grafted onto a Common Rootstock and Grown at Two Locations in Puerto Rico

2011 ◽  
Vol 21 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Ricardo Goenaga ◽  
David Jenkins
Keyword(s):  
Fruit Quality ◽  
Ethnic Diversity ◽  
Soluble Solids ◽  
Quality Traits ◽  
Tropical Fruit ◽  
Solids Concentration ◽  
Nephelium Lappaceum ◽  
Significant Difference ◽  
Fruit Quality Traits ◽  
Soluble Solids Concentration

The globalization of the economy, increased ethnic diversity, and a greater demand for healthy and more diverse food products have opened a window of opportunity for the commercial production and marketing of tropical fruit, including rambutan (Nephelium lappaceum). There is a lack of formal experimentation to determine yield performance and fruit quality traits of rambutan cultivars. Eight rambutan cultivars (Benjai, Gula Batu, Jitlee, R-134, R-156Y, R-162, R-167, and Rongren) grown on an Ultisol and an Oxisol soils were evaluated for 5 years at Corozal and Isabela, PR, respectively. There was a significant difference in the number and weight of fruit per hectare between locations, averaging 415,103 fruit/ha and 13,826 kg·ha−1, respectively, at Corozal and 167,504 fruit/ha and 5149 kg·ha−1, respectively, at Isabela. At Corozal, ‘R162’ had the highest 5-year mean for number and weight of fruit per hectare, but this cultivar was not significantly different from the rest except for ‘Benjai’ and ‘R-156Y’, which had significantly lower values. At Isabela, cultivars Gula Batu and R-162 had significantly higher number of fruit per hectare but the latter was not different from ‘Benjai’. Overall, there were no differences in soluble solids concentration except for cultivars Gula Batu and R-156Y, which had significantly lower values at both locations. Cultivar R-162 had higher number and weight of fruit per hectare and high soluble solids concentration at both locations, making it suitable for planting in various agroenvironments particularly on Ultisols typical of the humid tropics.

scholarly journals Preventing the Undesired Surface Veiling after Nanolime Treatments on Wall Paintings: Preliminary Investigations

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1083
Author(s):  
Teresa López-Martínez ◽  
Jorge Otero
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Significant Advance ◽  
Artificial Ageing ◽  
Wall Paintings ◽  
Chemical Cleaning ◽  
Conservation Practice ◽  
Before And After ◽  
Non Destructive ◽  
Mechanical Cleaning ◽  
Destructive Methods

During the last decades, the discovery of nanolime and its introduction in the field of Cultural Heritage has entailed a significant advance for the consolidation of historic wall paintings. Nevertheless, its use is not completely generalized yet within the conservation practitioner’s community due to its undesired white veiling deposit on the surface after treatment which usually covers the pictorial layer. Given the scarcity of existing literature which specify how to mitigate this undesired side-effect, the aim of this work is to carry out the first assessment of possible cleaning and treatment methods to eliminate those deposits and, at the same time, to analyse their effects on the consolidation properties. To do that, we have developed laboratory fresco wall paintings specimens. After applying an artificial ageing cycle to all of them, we consolidated them with CaloSil IP25, one of the most currently used commercial product in the practice. The elimination of the whitish deposits has been investigated with different methods: (1) wiping off the superficial excess of product immediately after each application during the treatment; (2) mechanical cleaning (scalpel) after consolidation; chemical cleaning with rigid gels of water (3), ethylenediaminetetraacetic acid (EDTA) (4) and citric acid (5) after consolidation. The effectiveness of each cleaning method has been assessed by non-destructive methods before and after the consolidation, and repeated after cleaning, by measuring differences in colour, water absorption by capillarity (i.e., sponge test), superficial adhesion (i.e., Scotch Tape Test) and by quantifying the thickness of the deposits eliminated by means of photogrammetry. Results show that both the mechanical cleaning and the removal of the excess of product after each application during the treatment yielded the most promising results for conservation practice.

Application of the ADUFR Process to Brewery Effluent on a Laboratory Scale

1992 ◽  
Vol 25 (10) ◽  
pp. 95-105 ◽  
Author(s):  
N. K. H. Strohwald ◽  
W. R. Ross
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Rest Period ◽  
Substantial Effect ◽  
Test Period ◽  
High Rate ◽  
Chemical Cleaning ◽  
Solids Concentration ◽  
Load Rate ◽  
Brewery Effluent

The application of the high rate ADUFR (Anaerobic Digestion - Ultrafiltration) process to brewery effluent was investigated over an 80 day test period. Performance data on both the anaerobic digester and ultrafiltration unit is presented. At stabilised conditions, space load rates of 15 kgCOD.m−3.d−1 could be achieved at hydraulic residence times of 0.5-0.8 days, with COD removal efficiencies between 96 and 99%. Linear flow velocity across the membrane surface and suspended solids concentration of the biomass were found to have a substantial effect on ultrafiltration membrane flux. No membrane fouling was experienced throughout the test period and flux values of 10-18 l.m−2.h−1 (LMH) could be maintained without resorting to chemical cleaning. Dormant sludge was reactivated rapidly, after a two month rest period. A space load rate of 8 kgCOD.m−3.d−1 at a retention time of 0.5 days could be reached within seven days from restart.

scholarly journals Generative and Vegetative Traits of the 'Granny Smith' Apple Grown under an Anti-Insect Photoselective Red Net

Poljoprivreda ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 34-42
Author(s):  
Tomislav Jemrić ◽  
Mia Brkljača ◽  
Marko Vinceković ◽  
Ana Marija Antolković ◽  
David Mikec ◽  
...  
Keyword(s):  
New Technology ◽  
Mesh Size ◽  
Titratable Acidity ◽  
Apple Orchard ◽  
Soluble Solids ◽  
Starch Degradation ◽  
Light Manipulation ◽  
Solids Concentration ◽  
Significant Difference ◽  
Vegetative Traits

Anti-insect photoselective nets present a new technology that combines light manipulation and pest protection in orchards. In this study, the effect of the anti-insect photoselective red net on the generative and vegetative traits was studied in an apple orchard near the city of Zadar, Croatia. 'Granny Smith' apples were grown on M9 rootstock and raised as slender spindles. The experiment consisted of two treatments: the trees covered with the red photoselective anti-insect nets (AGRITECH S. r. l., Eboli, Italy; mesh size of 2.4 × 4.8 mm) and uncovered trees as control. Yield, percentage of fruit with diameter >70 mm and fruit mass were not significantly different between treatments. L* color value was higher on fruit skin grown under the red net, and there was no significant difference in other color values (a*, b*, C* and h°). Soluble solids concentration (SSC) and total flavonoid content were significantly lower in fruit grown under red net than in control, and there was no significant difference in titratable acidity (TA), SSC/TA ratio, starch degradation and Streif maturity index. Red net proved to be effective against fruit red blush development (undesirable trait for 'Granny Smith' apple) and sunburn damage occurrence.

scholarly journals Poultry Ownership and Genetic Antibiotic Resistance Determinants in the Gut of Preschool Children

2021 ◽  
Author(s):  
Jessica M. Brogdon ◽  
Ali Sié ◽  
N. Clarisse Dah ◽  
Lucienne Ouermi ◽  
Boubacar Coulibaly ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Logistic Regression Model ◽  
Genetic Resistance ◽  
Tetracycline Resistance ◽  
Antibiotic Administration ◽  
Resistance Determinants ◽  
Confounding Variables ◽  
Significant Difference ◽  
The Relationship ◽  
Resistance Data

Zoonotic transmission is likely a pathway for antibiotic resistance. Data from a randomized trial of pediatric antibiotic administration were secondarily evaluated to determine if poultry ownership was significantly associated with the presence of gut genetic antibiotic resistance determinants among 118 children in Burkina Faso. Antimicrobial resistance (AMR) determinants were classified using DNA sequencing. We measured the relationship between genetic resistance determinants and chicken ownership using a logistic regression model adjusted for confounding variables. Children in households reporting poultry ownership had four times the odds of tetracycline resistance determinants in the gut compared with those without household poultry (OR: 4.08, 95% CI: 1.08–15.44, P = 0.04). There was no statistically significant difference found for other antibiotic classes. Understanding the origins of antibiotic resistance may help spur the development of interventions to combat the global AMR crisis.

scholarly journals Flux recovery of ceramic tubular membranes fouled with whey proteins: Some aspects of membrane cleaning

2008 ◽  
pp. 101-109 ◽  
Author(s):  
Svetlana Popovic ◽  
Spasenija Milanovic ◽  
Mirela Ilicic ◽  
Natasa Lukic ◽  
Ivana Sijacki
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Whey Proteins ◽  
Total Flux ◽  
Chemical Cleaning ◽  
Membrane Processes ◽  
Membrane Cleaning ◽  
Hydroxide Solution ◽  
Resistance Reduction ◽  
Tubular Membranes

Efficiency of membrane processes is greatly affected by the flux reduction due to the deposits formation at the surface and/or in the pores of the membrane. Efficiency of membrane processes is affected by cleaning procedure applied to regenerate flux. In this work, flux recovery of ceramic tubular membranes with 50 and 200 nm pore size was investigated. The membranes were fouled with reconstituted whey solution for 1 hour. After that, the membranes were rinsed with clean water and then cleaned with sodium hydroxide solutions or formulated detergents (combination of P3 Ultrasil 67 and P3 Ultrasil 69). Flux recovery after the rinsing step was not satisfactory although fouling resistance reduction was significant so that chemical cleaning was necessary. In the case of 50 nm membrane total flux recovery was achieved after cleaning with 1.0% (w/w) sodium hydroxide solution. In the case of 200 nm membrane total flux recovery was not achieved irrespective of the cleaning agent choice and concentration. Cleaning with commercial detergent was less efficient than cleaning with the sodium hydroxide solution.

scholarly journals Comparative Analysis of Root Dentin Loss when Using Modern Mechanical Cleaning Instruments in Immature Permanent Teeth

Folia Medica ◽  
2020 ◽  
Vol 62 (2) ◽  
pp. 352-357
Author(s):  
Krasimir Hristov ◽  
Natalia Gateva ◽  
Nikolay Ishkitiev ◽  
Liliya Doitchinova
Keyword(s):  
Root Canal ◽  
Permanent Teeth ◽  
Micro Computed Tomography ◽  
Mean Values ◽  
Root Canals ◽  
Immature Teeth ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
Mechanical Cleaning

Introduction: The full decontamination and disinfection of the root canal system is essential for the success of regenerative endodontic procedures. The current literature does not have information regarding mechanical cleaning of immature teeth with contemporary endodontic instuments. Aim: To compare the thickness and volume of the dentin removed from the roots of immature teeth after endodontic preparation using XP-endo Finisher, GentleFile Brush and a standard H-file scraping technique through micro-computed tomography. Methods: The study included 51 immature permanent molars. Endodontic access was prepared and without performing preliminary extirpation of the pulp, the teeth were divided into three groups. The first group of teeth were instrumented for two minutes with XP-endo Finisher, the second - two minutes with Gentlefile Brush, in the third group the root canals walls were scraped with a No. 40 H-file. The thickness and the volume of the removed dentin was assessed using micro-CT imaging before and after the use of the instruments. Results: There is no statistically significant difference in the mean values of thickness of dentin removed between the teeth, prepared with XP-endo finisher and Gentlefile Brush. When comparing the mean values of volume of dentin removed between the separate groups, a statistically significant difference was discovered for every compared pair with the highest volume of removed dentin in the group prepared with a hand instrument. Conclusion: The endodontic systems tested when used in immature permanent teeth remove significantly less quantity of hard dental structures compared to a hand file for scraping the root canal.

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