Nutrient Removal in Sequential Batch Polishing Ponds

Water

Silvânia Lucas dos Santos¹  Adrianus van Haandel² 

[1] Department of Civil Engineering, Federal University of Rio Grande do Norte, Natal 58410 380, Brazil;Department of Civil and Environmental Engineering, Federal University of Campina Grande, 882-Universitário, Campina Grande 58428 830, Brazil;

关键词: polishing pond;    pH change;    nutrient removal;    flow-through and sequential batch regimes;    ammonia desorption;    phosphate precipitation;   

DOI  :  10.3390/w13111584

来源: DOAJ

【 摘 要 】

One of the main problems of waste stabilization ponds (WSP) is that they cannot remove nutrients when treating wastewater. Polishing ponds (PP) can efficiently remove nitrogen and phosphorus from effluents after efficient anaerobic pretreatment. It shown that the feasibility of nutrient removal is directly related to the pH that is established in the ponds. WSP normally operate at near neutral pH, but the biological processes that develop in PP tend to cause an elevation of pH and this, in turn, triggers the mechanisms of nutrient removal in ponds. In PP oxygen production by photosynthesis predominates over the oxidation of organic material. The net oxygen production has an equivalent CO₂ consumption and this induces an increase in pH. The mechanism for nitrogen removal was identified as the desorption of ammonia from the liquid phase of the ponds. It was established that in ponds with a uniform concentration profile in the liquid phase the process developed in accordance with Fick’s law. The governing mechanism of phosphorus removal was precipitation with ions present in the wastewater, presumably calcium and magnesium. Polishing ponds can be operated with two different hydrodynamic regimes: flow-through (FTPP) and sequential batch (SBPP) ponds. The SBPP have the advantage that the pH elevation is more rapid, and that the final pH is higher.

【 授权许可】

Unknown