Further contributions to the understanding of nitrogen removal in waste stabilization ponds

Abstract

A set of experiments were conducted in Brazil in a pilot-scale waste stabilization pond (WSP) system (a four-maturation-pond series) treating an upflow anaerobic sludge blanket (UASB) reactor effluent. Over a year and a half the pond series was monitored under two flow rate conditions, hence also different hydraulic retention times and surface loading rates. On-site and laboratory trials were carried out to assess: (i) ammonia losses by volatilization using acrylic capture chambers placed at the surface of the ponds; (ii) organic nitrogen sedimentation rates using metal buckets placed at the bottom of the ponds for collecting settled particulate matter; (iii) nitrogen removal by algal uptake based on the nitrogen content of the suspended particulate matter in samples from the ponds' water column. In addition, nitrification and denitrification rates were measured in laboratory-based experiments using pond water and sediment samples. The pond system achieved high nitrogen removal (69% total nitrogen and 92% ammonia removal). The average total nitrogen removal rates varied from 10,098 to 3,849 g N/ha·d in the first and the last ponds, respectively, with the following fractions associated with the various removal pathways: (i) 23.5-45.6% sedimentation of organic nitrogen; (ii) 13.1-27.8% algal uptake; (iii) 1.2-3.1% ammonia volatilization; and (iv) 0.15-0.34% nitrification-denitrification.

Transformation of Waste Stabilization Ponds: Reengineering of an Obsolete Sewage Treatment System

“…In the 1960s, it became evident that in addition to the removal of organic material and pathogens, the removal of the nutrients, nitrogen and phosphorus, is of vital importance to protect recipient bodies. However, the research aimed at removing nutrients by Pano and Middlebrooks (1982) [4], Bastos et al (2018) [5], Zimmo et al (2003) [6], and Camargo Valero and Mara (2010) [7] showed that nitrogen removal is, at best, partial, and the phosphorus removal is poor (see Gomez et al (2000)) [8]. The reason for this failure is that the pH in a WSP remains close to the neutral point.…”

Transformação de lagoas de estabilização: reengenharia de um sistema obsoleto de tratamento de águas residuárias

“…Nos anos 60 do século passado, tornou-se evidente que, além da remoção do material orgânico e dos patógenos, a remoção dos nutrientes nitrogênio e fósforo é de vital importância para proteger os corpos receptores. Entretanto, pesquisas visando à remoção de nutrientes (PANO;MIDDLEBROOKS, 1982;BASTOS et al, 2018;ZIM-MO;VAN DER STEEN;GIJZEN, 2003; CAMARGO VALERO; MARA, 2010) mostraram que a remoção de nitrogênio é somente parcial e a remoção de fósforo não é factível. A razão desse insucesso se deve ao principalmente ao pH, que em lagoas de estabilização mantém-se praticamente neutro.…”

Performance assessment of nitrogen pollution purification by phytodepuration: case of Temacine pilot station (Algeria)

“…The temperature of the treated effluent is still variable and lower than that recorded at raw water level, this decrease is due to the stagnation of treated water in the basin, whereas, for the raw water, it can be due to the use of hot water as well as the movement of wastewater in the sewer pipes which increase its temperature. These differences do not influence the selection of the microorganisms responsible for purification, but they can play an important role during the warmer months and increase the volatilization of ammonia in the basin (Bastos et al 2018). It is important to note that, as with dissolved oxygen, the temperatures may vary depending on the vertical profile of the water basin layers, and the period of thermal stratification is generally attributed to the warm period.…”

“…• The evolution of nitrates indicates a decrease in their quantity after phytodepuration which is explained by the quantities of organic nitrogen eliminated in the basin by trapping in the roots ranging between 45 and 98%, and the plants assimilate between 10 and 39% (Jetten 2002). The mechanisms responsible for the removal of the remaining organic nitrogen may be nitrification, denitrification or anaerobic oxidation of ammonium (Bastos et al 2018;Wang and Chu 2016).…”

“…Each of these reactions depends on the state of the medium oxidation and the availability of dissolved oxygen (Sawaittayothin and Polprasert 2006). In the presence of plants, the main nitrogen removal reactions are nitrification/denitrification and assimilation by plants (Bastos et al 2018;Chen et al 2017;Li et al 2018). • Denitrification according to the reaction:…”