Pilot electrochemical prevention of reclaimed water irrigation clogging: Function interactions and microbial metabolism

The widespread use of reclaimed water has alleviated the water resource crisis worldwide, but long-term use of reclaimed water for irrigation, especially in agricultural countries, might threaten the soil environment and further affect groundwater quality. An in-situ experiment had been carried out in the North China Plain, which aimed to reveal the impact of long-term reclaimed water irrigation on soil properties and distribution of potentially toxic elements (As, Cd, Cr, Hg, Zn and Pb) in the soil profile as well as shallow groundwater. Four land plots were irrigated with different quantity of reclaimed water to represent 0, 13, 22 and 35 years’ irrigation duration. Pollution Load Index (PLI) values of each soil layer were calculated to further assess the pollution status of irrigated soils by potentially toxic elements (PTEs). Results showed that long-term reclaimed water irrigation caused appreciable increase of organic matter content, and might improve the soil quality. High soil organic matter concentrations conduced to high adsorption and retention capacity of the soils toward PTEs, which could reduce the risk of PTEs leaching into deep layers or shallow groundwater. Highest levels of Cr, Pb and Zn were observed at 200–240 cm and 460–500 cm horizons in plots. Longer irrigation time (35 years and 22 years) resulted in a decreasing trend of As, Cd, Hg, Pb and Zn in lower part of soil profiles (>540 cm) compared with that with 13-years’ irrigation years. Long-term reclaimed water irrigation still brought about increases in concentrations of some elements in deep soil layer although their content in soils and shallow groundwater was below the national standard. Totally speaking, proper management for reclaimed water irrigation, such as reduction of irrigation volume and rate of reclaimed water, was still needed when a very long irrigation period was performed.

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The Impact of Reclaimed Water Irrigation on Soil Microbial Community Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.3635 ◽

2014 ◽

Vol 955-959 ◽

pp. 3635-3639 ◽

Cited By ~ 1

Author(s):

Ji Hua Wang ◽

Xue Gong ◽

Jian Fei Guan ◽

Hui Yan Xing

Keyword(s):

Community Structure ◽

Microbial Community ◽

Microbial Community Structure ◽

Soil Microbial Community ◽

Soil Column ◽

Reclaimed Water ◽

Soil Microbial Community Structure ◽

Soil Microbial ◽

The Impact ◽

Reclaimed Water Irrigation

The reclaimed water treated in a Harbin recycled water plant has been taken as a target of research, by using microbial traditional culture method and tablet coated counting method, discussing the influence of the reclaimed water irrigation on soil microbial community structure through the method of short-term indoor simulated soil column irrigation. The results shows that the reclaimed water irrigation can significantly increase the quantity of bacteria and actinomycetes in the surface 0-20 cm layer soil, but it has little affect on 20-40 cm and 40-60 cm layer soil. Microbial community structure and diversity were changed relatively with the irrigation of reclaimed water, which embodied the increase or decrease of dominant and subdominant groups, the disappearance of non-dominant groups sensitive to reclaimed water, the appear or disappear of the other part of the occasional groups.

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Characterizing the Variation of Dissolvable PAHs in Receiving Water in a Reclaimed Water Irrigation Region

Water ◽

10.3390/w12102766 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2766

Author(s):

Yajun Wang ◽

Binghua Li ◽

Ying Ma ◽

Lihu Yang ◽

Xianfang Song

Keyword(s):

Environmental Protection Agency ◽

Environmental Pollutants ◽

Reclaimed Water ◽

Aquatic Organisms ◽

Temporal Variations ◽

Ecosystem Functions ◽

Factors Affecting ◽

Polycyclic Aromatic ◽

Potential Factors ◽

Reclaimed Water Irrigation

Long-term wastewater and reclaimed water irrigation systems constitute the major processes in local water circulation, which concomitantly introduce plenty of undesirable substances that can threaten water quality, ecosystem functions and human health. At the Southeast Reclaimed Water Irrigation Region (SRWIR) of Beijing, wastewater irrigation was adopted from 1969 to 2002, and second-treated effluents (reclaimed water) has been used thereafter. Polycyclic aromatic hydrocarbons (PAHs) were the most ubiquitously detected contaminant in wastewater and reclaimed water and are reported to be carcinogenic. Hence, we measured the concentrations of dissolved sixteen United States Environmental Protection Agency (USEPA) priority PAHs in surface water and groundwater at the SRWIR to characterize their spatial and temporal variations, and to clarify the role of reclaimed water to natural water. The concentration of 16 individual PAHs in reclaimed water, rivers and groundwater varied from 339.4 to 636.2 ng/L, 359.1 to 3,435.0 ng/L and 216.5 to 488,205.2 ng/L, respectively. The lower aromatic rings of PAHs prevailed in aquatic environments rather than the higher ones. Thereinto, naphthalene was the predominant isomer within the highest concentration reached to 486,600 µg/L. The groundwater samples had higher PAHs concentrations at Tongzhou district which attributed to the higher vulnerability of aquifer. Additionally, strong correlations between PAHs and total nitrogen, nitrate, dissolved oxygen and electrical conductivity suggested those potential factors affecting the photo degradation and/or biodegradation of PAHs. The relationship identified between PAHs concentrations and physical and chemical indices would help us to enhance the understanding migration and transformation of PAHs spatially and temporally, enable us to assess the potential risks of the environmental pollutants to aquatic organisms and human water supplies.

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