Effect of Pine Waste and Pine Biochar on Nitrogen Mobility in Biosolids

Abstract

Humanity produces ∼27 kg of dry matter in biosolids per person per year. Land application of biosolids can improve crop production and remediate soils but may result in excessive nitrate N (NO-N) leaching. Carbonaceous materials can reduce the environmental impact of biosolids application. We aimed to ascertain and compare the potentials for Monterey pine ( D. Don)-sawdust-derived biochars and raw sawdust to reduce NO-N leaching from biosolids. We used batch sorption experiments 1:10 ratio of material to solution (100 mg kg of NH or NO) and column leaching experiments with columns containing biosolids (2.7% total N, 130 mg kg NH and 1350 mg kg NO) mixed with soil, biochar, or sawdust. One type of low-temperature (350°C) biochar sorbed 335 mg kg NH, while the other biochars and sawdust sorbed <200 mg kg NH. None of the materials sorbed NO. Biochar added at rates of 20 to 50% reduced NH-N (<1% of total N) leaching from columns by 40 to 80%. Nitrate leaching (<7% of total N) varied little with biochar form or rate but was reduced by sawdust. Incorporating dried sawdust with biosolids showed promise for mitigating NO-N leaching. This effect likely is due to sorption into the pores of the biochar combined with denitrification and immobilization of N rather than chemical sorption onto surfaces.

Potential Environmental Benefits from Blending Biosolids with Other Organic Amendments before Application to Land

“…Lignite lessened the beneficial growth effects of adding biosolids to soil and exacerbated N 2 O production. However, sawdust and partially pyrolyzed biochars (resulting from heterogeneous temperatures in the pyrolysis kiln) have provided convincing results from laboratory and glasshouse trails when applied with biosolids to the same soils (Paramashivam et al, 2016b). In batch sorption and column leaching experiments, biochars and fresh sawdust failed to sorb NO 3 − , but NO 3 − leaching was reduced by Pinus radiata D. Don sawdust with a low moisture content.…”

“…Most biosolids contain elevated concentrations of heavy metals (McBride et al, 1999) and organic contaminants, including polychlorinated biphenyls (PCBs), dioxins, polyaromatic hydrocarbons Ogilvie, 1998), (Sanchez-Monedero et al, 2004), (Rouch et al, 2011), Aerobic sludge 7.6-8.2 2.2 (1.7) 74 (8.5) 101 n/g 2.3 208 526 (Ogilvie, 1998), (Magesan and Wang, 2003), (Rigby and Smith, 2013) Anaerobic sludge 5.8-8.1 4 14 n/g n/g 1.7 (0.2) 520 100 (Ogilvie, 1998), (Magesan and Wang, 2003), (Civeira and Lavado, 2008), (Rigby and Smith, 2013) Digested dry sludge 6.4-7.3 5.5 (0.4) 53 (9.5) 39 n/g 94 4732 431 (Ogilvie, 1998), (Rouch et al, 2011), (Correa et al, 2006) Aged biosolids (>3 yr) 4.4-4.5 2.4 (0.8) n/g n/g n/g 65 208 1848 (Ogilvie, 1998), (Nash et al, 2011), (Mok et al, 2013), (Laidlaw et al, 2012) Aged biosolids (>20 yr) 4.5 n/d 51.6 16.7 (0.7) 107 (2.3) 51 (2.2) 130 (7.3) 1352 (2.5) (Paramashivam et al, 2016b) † EC, electrical conductivity. ‡ CEC, cation exchange capacity.…”

“…Pyrolysis of organic waste such forestry, garden, and agricultural wastes produces biochar. Biochar shows promise to sorb xenobiotic organic contaminants (Spokas et al, 2009;Wang et al, 2010;Zhang et al, 2010); inorganic components including NH 3 , N 2 O, NO 3 − , and NH 4 + (Taghizadeh-Toosi et al, 2011;Taghizadeh-Toosi et al, 2012;Paramashivam et al, 2016b); and metals (Uchimiya et al, 2010;Park et al, 2011). Knowles et al (2011) and Gartler et al (2013) demonstrated that biosolids-biochar mixtures resulted in the same or greater biomass production in a range of species compared with adding biosolids alone.…”

“…that degrade lignin in wood waste can enhance the degradation of persistent organic pollutants such as pentachlorophenol (Mileski et al, 1988). Microbial inhibition in biosolids caused by poor aeration, low pH, or high concentrations of metals may be reduced by mixing the biosolids n/g (Paramashivam et al, 2016b), (Wilén et al, 2004) Pine ( (12) 55 (12) (Enders et al, 2012), (Pereira Calvelo et al, 2011), (Hina et al, 2010) n/a n/a n/a n/a (Zhang et al, 2015) 600 9.6 37.1 0.4 n/a n/a 42.6 n/a n/a n/a n/a Lignite New Vale, New Zealand with organic amendments (Song and Schobert, 1996;Pehlivan and Arslan, 2007;Chassapis et al, 2009;Knowles et al, 2011;Simmler et al, 2013;Doskocil et al, 2015). Xenobiotics can be immobilized or entrapped within the micropores of organic soil amendment (Fetzner, 2000).…”

Biosolids and biochar application effects on bahiagrass herbage accumulation and nutritive value

“…Recycling biosolids to agricultural land, however, poses some challenges that often restrict the use of biosolids in many parts of the United States. These include variable nutrient composition and availability in various biosolids materials (Singh & Agrawal, 2008; Wang, Kimberley, & Schlegelmilch, 2003), unbalanced N/P ratio relative to crop requirement which often results in excessive P accumulation in soil (Antille, Sakrabani, & Godwin, 2014) and subsequent unintended environmental impacts on water quality (Paramashivam et al., 2016). An alternative to minimize negative environmental risk while enhancing nutrient utilization by the crop is to reduce the lability of nutrients in biosolids.…”