Research paper
Domestic wastewater infiltration process in desert sandy soil and its irrigation prospect analysis

https://doi.org/10.1016/j.ecoenv.2020.111419Get rights and content
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Highlights

  • Domestic wastewater irrigation improves plant growth in desert soil.

  • Plant growth reduces the infiltration rate of domestic wastewater in desert soil.

  • Domestic wastewater irrigation improves desert soil microbial community.

  • Tertiary treated wastewater has big potential in desert vegetation recovery.

  • Domestic wastewater irrigation and plant growth increase soil function restoration.

Abstract

Although domestic wastewater and its reclaimed water are alternative water resources in arid region, investigation of their negative effect must be done to prevent environmental pollution. In this paper, a short-term column experiment was conducted to simulate the infiltration process of wastewater in desert soil. Alfalfa was planted and irrigated with fresh water for control (CK), tertiary treated domestic wastewater (TTW), secondary treated domestic wastewater (STW) and raw domestic wastewater untreated (RW). The effect of wastewater application on desert soil, drainage and plant properties was evaluated. Experimental results demonstrated that the tested desert soil has no soil structure, organic matter, nor microbial community while possess high infiltration rate. The use of wastewater significantly improved plant growth, and the biomass of TTW, RW, STW were 5.5, 4.3, 2.9 times of CK. The infiltration rate of water in bare soil was high (high to low: TTW, CK, RW, STW), while plant growth reduced infiltration rate (ca. 40% with TTW and RW). Wastewater irrigation and plant growth decreased soil zeta potential, while increased formation of aggregates and bacterial abundance and diversity in soil. Top soil (0–30 cm) accumulation of nitrogen (N), phosphorus (P), organic matter and E. coli was evidenced and all could go down to deep soil and drainage with constant wastewater use. It was concluded that domestic wastewater had big potential in desert soil vegetation recovering and function restoration. Nevertheless, the N, salt, P and organic matter and E. coli in wastewater could give rise to desert soil and groundwater contamination if improper treatment was used.

Keywords

Water reuse
Desert soil restoration
Vegetation recovery
Infiltration
Alfalfa

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