Table 1.
Hot spots of struvite precipitation and their operational impact (adapted from Le Corre et al., 2009).
| Operational hotspots | Effects | Type of plant | References |
|---|---|---|---|
| Pipes carrying supernatants of AD. | 2.5 cm accumulation. | WWTP (USA) | Rawn et al. (1937) |
| Activated sludge process - pump onto separating screen. | Diameter reduction from 310 mm to 150 mm. | Hyperion WWTP (USA) | Borgerding (1972) |
| Anaerobic supernatant: pump impellers, pipes, etc. | – | Livestock WWTP (USA) | Booram et al. (1975) |
| Outfall pipelines, waste pumps, pipelines. | Accumulation: from 5.88 up to 14.44 mm in aerators; from 8 up to 28 mm in pipes carrying digester effluents. | Pig waste treatment plant (Singapore) | Mohajit et al. (1989) |
| Pipes from sludge supernatant system. | Accumulation along 5.6 km of pipes. | WWTP (USA) | Ohlinger et al. (1999) |
| Precipitation in pipelines - sludge holding tank to the centrifuges. | Pipes bore reduction from 100 to 50 mm. | WWTP (UK) | Williams (1999) |
| Pipes of centrate liquors. | Pipe diameter reduction from 150 to 60 mm in 12 weeks. | Sludge treatment plant (UK) | Doyle and Parsons (2002) |
| Pipes of anaerobic supernatants. | Pipe diameter reduction. | Pilot fluidised bed reactor plant, WWTP (Italy) | Battistoni et al. (2005) |
| Streaming pipes. | Two-month build up in a rubber lined 90° elbow. | WWTP (USA) | Nethling and Benisch (2004) |