نتایج جستجو برای: oxidation ponds
تعداد نتایج: 123246 فیلتر نتایج به سال:
One of the main problems waste stabilization ponds (WSP) is that they cannot remove nutrients when treating wastewater. Polishing (PP) can efficiently nitrogen and phosphorus from effluents after efficient anaerobic pretreatment. It shown feasibility nutrient removal directly related to pH established in ponds. WSP normally operate at near neutral pH, but biological processes develop PP tend ca...
An experiment was conducted to assess the effect of different harvest draining techniques of fish ponds on water quality and fish growth in subsequent culture cycles. Fifteen tilapia ponds of 200 m2 were harvested using five different harvest draining techniques. After harvest, these ponds were stocked with Nile tilapia (Oreochromis niloticus) at 2 fish m-2. Fish with an initial size of 11 to 1...
Seasonal changes in abundance of nitrifiers (ammonia-oxidizing and nitrite-oxidizing bacteria) in surface and bottom water of freshwater ponds were examined with respect to temperature, DO, pH as well as concentration of ammonia and nitrite. The most probable number (MPN) of ammonia-oxidizers in different ponds varied from 1297 +/- 3.6 to 1673.23 +/- 0.36 ml(-1) in bottom and 720.5 +/- 8.1 to 9...
This study investigated the impact of waterfowl on the bacteriological quality of village ponds in East Yorkshire, north-east England. Water and sediment samples were collected from ponds with and without resident ducks and geese; faecal indicator and potentially pathogenic bacteria were assayed by membrane filtration and by selective enrichment. Escherichia coli, faecal streptococci and, to a ...
We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, s...
Several species of southeastern amphibians completely or facultatively depend upon small, ephemeral isolated ponds for reproduction, and inhabit surrounding uplands for much of their adult lives. However, spatio-temporal dynamics of pond use is little known. Since 1994, eight ephemeral ponds embedded within frequently (n=4) or infrequently (n=4) burned longleaf pine uplands in the Ocala Nationa...
The effectiveness of alum (aluminum sulfate) in reducing the concentrations of potential pollutants in pond effluents was investigated in catfish production ponds. Application of alum at 50 mg/l to water remaining in ponds immediately after seining for harvest did not generally result in significantly greater removal of nutrients and solids than did settling alone, although removal rates of som...
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