Impact of Land‐Applied Tertiary‐Treated Effluent on Soil Biochemical Properties

Abstract

Land application is increasingly used for the disposal and treatment of effluents. We investigated how irrigation of tertiary‐treated domestic effluent influenced 14 soil biochemical properties in a Monterey pine (Pinus radiata D. Don) forest on volcanic soils. The soils were irrigated with either effluent or water at two loading rates (49 and 74 mm wk−1). Surface soils (0–5 cm) were collected from the effluent‐irrigated and adjacent nonirrigated control sites annually for 3 yr and for 2 yr from the water‐irrigated sites. Effluent irrigation significantly (P < 0.05) increased several soil properties including pH, invertase activity, denitrification, mineralizable N, and extractable nitrate. These increases were not observed in the water‐irrigated soils suggesting that the changes resulted from effluent chemistry rather than additional water loading. Phosphatase activity decreased with both water‐ and effluent‐irrigation. No changes were observed in total N, total C, basal respiration, microbial biomass, sulfatase activity, or extractable ammonium in the effluent‐ and water‐irrigated soils. Both rates of effluent application had the same effect on soil properties indicating that the threshold rate that changed soil properties was ≤49 mm of effluent per week.

Nitrogen forms, pH and total carbon in a soil incubated with treated sewage effluent

“…The volatilization of NH 3 -N in acid soils irrigated with the alkaline effluent was a well-known fact (Smith et al, 1996) and might have also occurred in this study. Denitrification processes have been found to be dependent on the effluent organic C concentration (Bouwer and Chaney, 1974;Schipper et al, 1996), the available C in soil (Feigin et al, 1991) and, the irrigation effect on soil resulting in decrease of O 2 (Polglase et al, 1995). In this context, a two fold (Schipper et al, 1996) to fifty fold increases (Friedel et al, 2000) of denitrification rates in TSE irrigated soils have been reported.…”

“…Denitrification processes have been found to be dependent on the effluent organic C concentration (Bouwer and Chaney, 1974;Schipper et al, 1996), the available C in soil (Feigin et al, 1991) and, the irrigation effect on soil resulting in decrease of O 2 (Polglase et al, 1995). In this context, a two fold (Schipper et al, 1996) to fifty fold increases (Friedel et al, 2000) of denitrification rates in TSE irrigated soils have been reported. Also, the microbial N immobilization should be considered because: (i) most of the effluent-N occurred as NH 4 + -N that represented the preferred microbial inorganic-N (Stevenson, 1986); (ii) after STSE application to the soil, TN concentrations increased (Fig.…”

Waste Water Use in Crop Production: A Review

“…Such effect may be attributed to the high content of basic cations viz. Na + , Ca 2+ and Mg 2+ in the WW, wh ich after accu mulat ion in surface soil layer for a long period of t ime [51], leads to increase soil pH. The increased in soil pH (Table 3) has been referred e xclusively to the high content of Ca 2+ and Mg 2+ of pharmaceutical effluents applied to the soil [30].…”

Land application of farm dairy effluent: Results from a case study, Wairarapa, New Zealand

“…This method has been used to treat effluent from townships, meatworks, dairy factories, and dairy farms (Schipper et al 1996;Selvarajah 1996;Cameron et al 1997;Tomer et al 1997;Sparling et al 2001). A major concern in New Zealand at present is the potential impact of farm dairy effluent (FDE) on the environment (Environment Waikato 1998;Wellington Regional Council 1999b).…”