a biofilm sequencing batch reactor with a volume of 1.42 m3, nylon nets providing a 4,140 m2/m3 support area for biofilms and an automated operation with 8 hour cycles was studied. the duration of the experiment was 135 days. removal efficiencies e≥ 80% were obtained for carbonaceous matter, producing an effluent with 31±26.8 mg/l of filtered cod, 7±3.6 mg/l of bod5 and 12±3.2 mg/l of toc. the ...

Maximization of short-rotation forest plantation yield requires frequent applications of nutrients, especially nitrogen (N). Whole-plant growth is known to be sensitive to the proportion of ammonium to nitrate (NH4:NO3). However, the extent to which N form affects root growth, branching and morphology is poorly understood, and these variables may have substantial impacts on plant nutrient and w...

Understanding the preference of a crop for forms nitrogen (N) is important to ensure efficient use N-sources in agriculture. A study was conducted assess nutrient uptake and dry matter yield six vegetable crops under different ratios ammonium- N (NH4+-N) nitrate-N (NO3–-N) growth medium. Seedlings cabbage, carrot, capsicum, knolkhol, lettuce, tomato, were supplied with five N-treatments (NH4+-N...

Coastal lagoons positioned along the land margin may play an important role in removing or transforming ‘reactive’ nitrogen during its transport from land to the ocean. Hog Island Bay is a shallow, coastal lagoon located on the ocean-side of the Delmarva Peninsula in Virginia (USA). External nitrogen inputs are derived primarily from agriculturally enriched groundwater, and these support, in pa...

[1] Ammonium and amino acid fluxes were examined as indicators of N and microbial food web dynamics in southern Lake Michigan during spring. Either NH4 + or a mixture of N-labelled amino acids (both at 4 mM N final concentration) was added to Lake Michigan water. Net fluxes were measured over 24 h under natural light and dark conditions using deck-top incubators and compared to microbial food w...

The influence of three salts (KN03, NH4N03 and (NH4>2S04) in different concentrations, on the growth and mineral composition of olive seedlings cultured in vitra and in greenhouse conditions, was studied. The best growth was obtained in in vitra culture through the applications of NH4N03, in concentrations of 10 and 20 mM of N. Addition of (NH4)2S04 clearly damaged the seedlings and increased t...

Futile plasma membrane cycling of ammonium (NH4 ) is characteristic of low-affinity NH4 + transport, and has been proposed to be a critical factor in NH4 + toxicity. Using unidirectional flux analysis with the positronemitting tracer N in intact seedlings of barley (Hordeum vulgare L.), it is shown that rapid, futile NH4 + cycling is alleviated by elevated K supply, and that low-affinity NH4 + ...

Nitrification of ammonia (NH4) is a critical component for improved systems of animal wastewater treatment. One of the most effective processes uses nitrifying microorganisms encapsulated in polymer resins. It is used in Japan in municipal wastewater treatment plants for higher nitrification rates, shorter hydraulic retention times (HRT), and lower aeration treatment cost. We evaluated whether ...

Plants mainly utilize inorganic forms of nitrogen (N), such as nitrate (NO3-) and ammonium (NH4+). However, the composition of the N source is important, because excess of NH4+ promotes morphological disorders. Plants cultured on NH4+ as the sole N source exhibit serious growth inhibition, commonly referred to as "ammonium toxicity syndrome." NH4+-mediated suppression of growth may be attributa...