Paul Campbell
Nutrient limitation – can activated sludge fix nitrogen?
Sometimes, the same question pops up a few times in one week. This week, we were asked about tracking nitrogen fixation in cases of suspected nutrient limitation. Some wastewater influents are low in nitrogen (ammonia & TKN). For example, pulp & paper processing usually doesn't contain appreciable amounts of TKN - and the same is true for some chemical plant influents. For macro nutrient requirements, operators add supplemental N in the form of ammonia or urea. But are the op
