Influence of sludge retention time on filtration performance and biomass characteristics in a hollow fiber membrane bioreactor

In this study, the filtration process and the biomass characteristics in a laboratory-scale submerged membrane bioreactor (MBR) equipped with a hollow fiber (HF) microfiltration membrane were studied at different solid retention times (SRT). The MBR was fed by synthetic wastewater and the organic loading rate (OLR) was 0.5, 0.2, 0.1, and 0.08 kg COD kg VSS−1 d−1 for 10, 30, 60, and 90 days of SRT, respectively. The hydraulic retention time was 8.4 h and the permeate flux was 6 L m−2 h−1(LMH). Data analysis confirmed that at all the studied SRTs, the HF-MBR operated very good obtaining of high quality permeates. Chemical Oxygen Demand (COD) removal efficiencies were higher than 95%. The best filtration performance was reached at SRT of 30 d. On the other hand, the respirometric analysis showed that biomass was more active and there was more biomass production at low SRTs. The concentration of soluble extracellular polymeric substances (EPS) decreased with increasing SRT. A decrease of soluble EPS caused a decrease of membrane fouling rate, decreasing the frequency of chemical cleanings. The floc size decreased with SRT increasing. At high SRTs, there was more friction among particles due to the increase of the cellular density and the flocs broke decreasing their size.

Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC) as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention) and deicing (curing), which could turn into an environmentally friendly and cost-effective deicing method.

Compressive behaviour of a tire recycled steel and textil fiber concrete subjected to fire

The use of rubber aggregates, steel and textile fibres recycled from tires in concrete is a solution that it is being studied by several authors around the world. A few works have been carried out at room temperature but very scarce at high temperatures. This paper presents the results of a research with the aim to evaluate the behaviour at high temperatures of a concrete made with different amounts of recycled textile and steel fibres from tires. The study considered five concrete compositions, with the same water/cement ratio (W/C=0.43), differing only in the type and quantity of fibers incorporated in the mixture. Thus, a reference composition (0% fiber), two compositions with 30 and 70kg/m3 of steel fibers and a composition with 2 and 4kg/m3 of textile fibers from tires were tested. The concrete was tested for a load level of 0.5fcd and different maximum temperature levels (20, 300, 500 and 700ºC).

Optical detection of fiber particles in water /

Mode of access: Internet.

Water filtration for asbestos fiber removal /

EPA-600/2-79-206.

Carbon fiber risk analysis.

Item 830-H-10 (microfiche)

Study of fiber release during routine maintenance of asbestos containing floor tile : cooperative research and development agreement with Chemical Specialties Manufacturing Association, Inc.

Mode of access: Internet.

Development of a streaming-fiber oil spill control system, Stage II /

Final report, issued December 1976.

Development of a streaming-fiber oil spill control system : stage II : modifications to large-scale model /

Includes bibliographical references.

Final environmental assessment/environmental impact report for the American Telephone and Telegraph Company fiber optic cable right-of-way project, Cheyenne, Wyoming to Sacramento, California /

On cover: AT&T fiber optics cable project, Cheyenne, Wyoming to Sacramento, California ... December 1987."

Questions and answers relating to the Textile Fiber Products Identification Act and regulations.

"April 1986."

Experimental and numerical simulation of the use of fiber reinforced composite materials for road side safety applications /

"May 1997."

Impact characteristics of glass fiber-reinforced composite materials for use in roadside safety barriers /

"January 1994."

Design of continuously reinforced concrete pavements using glass fiber reinforced polymer rebars /

"October 2005."

Impact characteristics of glass fiber-reinforced composite materials for use in roadside safety barriers. Final report.

Federal Highway Administration, McLean Va.