High levels of turbidity and suspended solids are the major disadvantages of aerated lagoons. Aerated lagoon effluent filtration was investigated by Horizontal Roughing Filter (HRF). Removal efficiencies were determined by examining total phosphorus (TP) and total Kjeldahl Nitrogen (TKN) from HRF influent and effluent, simultaneously. HRF pilot system located on effluent pump station of Qom was...

In many oceanic regions, growth of phytoplankton is nitrogen-limited because fixation of N2 cannot make up for the removal of fixed inorganic nitrogen (NH4+, NO2-, and NO3-) by anaerobic microbial processes. Globally, 30-50% of the total nitrogen loss occurs in oxygen-minimum zones (OMZs) and is commonly attributed to denitrification (reduction of nitrate to N2 by heterotrophic bacteria). Here,...

The effect which nitrogen has upon boron diffusion through oxynitride gate dielectrics has been studied with secondary ion mass spectroscopy of polycrystalline silicon–oxynitride–silicon structures, and with x-ray photoelectron spectroscopy of silicon–boron–oxynitride–silicon structures. These studies show that the indiffusion of boron results in removal of nitrogen from the oxynitride. This in...

Duckweed (Lemna minor L.) has a wide application in Turkey having suitable climatic conditions. In this study, the growth of duckweed was assessed in laboratory scale experiments. They were fed with municipal and industrial wastewater at constant temprature. COD, total nitrogen (TN), total phosphorus (TP) and ortho-phosphate (OP) removal efficiencies of the reactors were monitored by sampling i...

Over the past several decades, human activities have caused substantial enrichment of reactive nitrogen in China's coastal wetlands. Although anaerobic ammonium oxidation (anammox), the process of oxidizing ammonium into dinitrogen gas through the reduction of nitrite, is identified as an important process for removing reactive nitrogen, little is known about the dynamics of anammox and its con...

La/Fe/TiO₂ composite photocatalysts were synthesized by Sol-Gel method and well characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen-physical adsorption, and UV-Vis diffuse reflectance spectra (UV-Vis DRS). It is interesting that the doped catalysts were in anatase phase while the pure TiO₂ was in rutile phase. In addition, the composites possessed bette...

A two-stage upflow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen (TN) removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supernatant was pumped into the fi...

This study examines the suitability of natural silica sand as a low-cost adsorbent for the removal of ammoniacal nitrogen and heavy metals, particularly iron and zinc, from semi-aerobic stabilized landfill leachate. Leachate samples were collected from the Pulau Burung landfill site (PBLS) in Penang, Malaysia. The above-mentioned contaminants are highlighted in this study because of their unsaf...

The removal of gaseous ammonia in a system consisting of a biotrickling filter, a denitrification reactor and a polishing bioreactor for the trickling liquid was investigated. The system allowed sustained treatment of ammonia while preventing biological inhibition by accumulating nitrate and nitrite and avoiding generation of contaminated water. All bioreactors were packed with cattle bone comp...

Wetlands and ponds are frequently used to remove nitrate from effluents or runoffs. However, the efficiency of this approach is limited. Based on the assumption that introducing vertical mixing to water column plus carbon addition would benefit the diffusion across the sediment-water interface, we conducted simulation experiments to identify a method for enhancing nitrate removal. The results s...