Nutrient Removal by Chemical Post Treatment with Lime Following the Biological Stage

Abstract

Activated sludge is the common name of the suspended-growth biological processes used for the treatment of domestic and low-to medium-strength industrial wastewater. Activated sludge provides the conversion of organic matter into microbial culture, and then reproduced biomass is easily separated by gravity settling. Thereby organic matter content is eliminated from the influent. Activated sludge also provides adequate biological pathways for the elimination of nitrogen and phosphorus nutrients from wastewater by applying advance treatment methods [1-7]. The usual forms of phosphorus nutrients found in aquatic environments include orthophosphate, polyphosphate, and organic phosphate. Phosphorus compounds undergo hydrolysis and are converted to

Recovery of Phosphorus from Waste Water Profiting from Biological Nitrogen Treatment: Upstream, Concomitant or Downstream Precipitation Alternatives

“…Alternatively, addition of Ca(OH) 2 following high-rate biological treatment has also been suggested to raise pH, favouring ammonia stripping and CaP precipitation [212]. [75] Lack of ammonium in the N treated effluents allows raising of pH for precipitating MgP without the risk of favouring ammonia emission while recovering other minerals rather than MAP, such as newberyite [213] (which has a specific P content higher than MAP, see Table 1) and MPP (K-struvite) [75,76].…”