Long-term land application of biosolids–a case study

Abstract

Impact of long-term land application of biosolids on groundwater and soil quality of an application site, which had been operated for 8-15 years, was evaluated in this study. During and after the biosolids application, biosolids-amended soil, groundwater, and background soil samples were collected mainly for pathogen, nitrogen, phosphorus, and heavy metal analyses. Soil test data showed that there was no heavy metal accumulation in the biosolids-amended soil even after 10 years of biosolids application. Similar results were also observed from the groundwater samples in which the heavy metal concentrations in all groundwater samples were well below the maximum contamination levels of the drinking water standards. In addition, bacteriological levels of the soil and groundwater samples were close to the background level and below the permissible limits, respectively, thereby showing no pathogen contamination. However, nitrate-nitrogen contamination of the groundwater was occasionally observed probably due to an excess loading of the biosolids in the past. This problem can be alleviated by applying biosolids at agronomic rates so that no excess nitrogen is available for leaching down to the groundwater.

Achilles heel of environmental risk from recycling of sludge to soil as amendment: A summary in recent ten years (2007–2016)

“…Jalali and Arfania (2011) thought that amendment of sludge to sandy soil may pose little risk of groundwater becoming contaminated with Cd, Ni and Pb. Surampalli et al (2008) reported that recycling of sludge to soil did not lead to the accumulation of heavy metals in the groundwater, and they also found those concentrations well below drinking water standards. Taken together, the type of amended soil is crucial to the accumulation of heavy metals in groundwater.…”

“…Surampalli et al (2008) reported that amending too much sludge to soil over a ten year period could occasionally cause groundwater to become contaminated with nitrates. Backes et al (2013) also found a negative linear relationship between the sludge application rate to a sod substrate and base saturation.…”

“…Monitoring results obtained by Chen et al (2012) indicated nitrogen transport in runoff can lead to over-input to downstream surface water. Surampalli et al (2008) found that nitrate-nitrogen contamination of the groundwater was occasionally observed probably due to an excess amendment of sludge. Kang et al (2011) and Alleoni et al (2008) pointed out that long-term application of sludge to soil as fertilizer can increase potential risk for phosphorus loss to ground and surface waters.…”

Sewage Sludge Amendment Combined with Green Manuring to a Coastal Mudflat Salt-Soil in Eastern China: Effects on Soil Physicochemical Properties and Maize Yield

“…Approximately 78.4 billion metric tons of sewage sludge was derived from more than 2600 wastewater treatment plants in China in 2015 [15]. Agricultural application of sewage sludge is an effective waste disposal and soil amendment technique that can improve the chemical, physical, and biological characteristics of soils [16][17][18][19]. Sewage sludge is rich in organic matter and other nutrients and can be used for mudflat salt-soil amendment [9,20,21].…”

Groundwater Quality

“…The groundwater samples did not show any heavy metal accumulation and bacteriological levels of the groundwater were close to the background level. The only problem was that nitrate contamination in groundwater was occasionally detected due to an excess loading of the biosolids in the past (Surampalli et al, 2008). High concentrations of many contaminants were often found in groundwater near former biosolid stockpiling locations.…”