Characterization of labyrinth emitter-clogging substances in biogas slurry drip irrigation systems

Haitao Wang; Jiandong Wang; Chuanjuan Wang; Shuji Wang; Xuefeng Qiu; Yuechao Sun; Guangyong Li

doi:10.1016/j.scitotenv.2022.153315

Characterization of labyrinth emitter-clogging substances in biogas slurry drip irrigation systems

Sci Total Environ. 2022 May 10:820:153315. doi: 10.1016/j.scitotenv.2022.153315. Epub 2022 Jan 19.

Authors

Haitao Wang¹, Jiandong Wang², Chuanjuan Wang³, Shuji Wang⁴, Xuefeng Qiu⁴, Yuechao Sun⁴, Guangyong Li⁵

Affiliations

¹ College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China; Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
² Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: wangjiandong@caas.cn.
³ Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
⁴ Institute of Water Conservancy and Hydroelectric Power, Hebei University of Engineering, Handan 056000, China.
⁵ College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China. Electronic address: lgyl@cau.edu.cn.

PMID: 35065127
DOI: 10.1016/j.scitotenv.2022.153315

Abstract

Drip irrigation is important for efficiently returning biogas slurry to fields. Elucidating the characteristics and components of clogging substances produced by labyrinth emitters in biogas slurry drip irrigation systems will help to develop various clogging substance-remediation strategies. However, previous studies were unable to characterize the clogging substances in emitters. Thus, we aimed to characterize and quantify the substances clogging emitters in a biogas slurry drip irrigation system and determine the micromorphology and dominance of microbial communities. Here, emitter discharge changes and the micromorphologies, phase compositions, and biological communities of clogging substances were studied via hydraulic performance tests, scanning electron microscopy-energy depressive spectra (SEM-EDS), and high-throughput sequencing. The degree of emitter-clogging increased over time (first quickly, then slowly) and was deeper at the end of the drip irrigation tape than at the head. The clogging substances were viscous agglomerations primarily comprising 0.3-1.5-μm particles. Their formation was affected by settlement with gravity, water pressure adhesion, and mobile biological adhesion. The dominant microbial communities in the clogging substances included Firmicutes (29.7%) and Proteobacteria (19%); the emitter-clogging substances primarily comprised water (85%) and composite dry matter. The water, dry matter, and extracellular polymer substance (EPS) weights in the clogging substances increased over time, but their relative proportions remained stable. In the composite dry matter, typical physical (organic carbon, Al₂O₃, and SiO₂), chemical (CaCO₃ and MgCO₃), and biological (EPS) clogging substances accounted for >50, 9, and 5.62% of the total dry matter mass, respectively. This study provides a good foundation and reference idea and will be very helpful to propose targeted solutions for solving the clogging of biogas slurry drip irrigation system.

Keywords: Biogas slurry drip irrigation; Discharge change; Microbial communities; Micromorphology; Phase composition.

MeSH terms

Agricultural Irrigation
Biofuels*
Microbiota*
Silicon Dioxide

Substances

Biofuels
Silicon Dioxide