Pollutant removal from swine wastewater and kinetics in constructed rapid infiltration system (CRI system)

ABSTRACT

The purpose of this paper is centred on the kinetics of removal of main pollutants in wastewater and to compared different hydraulic loading conditions of the constructed rapid infiltration system (CRI system) in terms of removal efficiencies, effluent concentrations, mass removal rate (MRR), and the first-order removal rate coefficient (k) of COD, TOC, NH₄⁺-N, TN, and TP. The results showed that the higher the hydraulic loading, the higher the effluent concentration. The results that synthesized hydraulic loading, effluent concentrations, removal efficiencies, and other conditions showed that the best hydraulic loading was 40 cm/d. When the hydraulic load was 40 cm/d, the effluent average concentrations of COD, TOC, NH₄⁺-N, TN, TP, Cu²⁺ and the removal efficiencies were 27.31 ± 16.40 mg/L, 86.11%, 10.55 ± 5.25 mg/L, 84.64%, 0.59 ± 0.87 mg/L, 99.60%, 143.31 ± 14.77 mg/L, 7.04%, 5.64 ± 1.38 mg/L, 79.20%, and 0.13 ± 0.47 mg/L, 97.51%, respectively. According to a kinetic study of the primary pollutants, the MRR increased with an increase in the hydraulic loading, except for ammonia nitrogen. CRI-3, CRI-4 were high significant correlated with ammonia nitrogen (with R²= 93.65% and R²= 95.03%, respectively), while CRI-2, CRI-3, and CRI-4 were high significant correlated with total nitrogen (with R²= 94.56%, R²= 96.70% and R²= 96.56% respectively).

GRAPHICAL ABSTRACT

KEYWORDS:

• Constructed rapid infiltration system
• swine wastewater
• hydraulic loading rate
• removal kinetics
• pollutants removal performance

Acknowledgements

The authors thank the Laboratory of Animal Husbandry Engineering, the Chongqing Academy of Animal Sciences and Scientific Observation, and the Experiment Station of Livestock Equipment Engineering in the Southwest, Ministry of Agriculture and Rural Affairs. We also thank LetPub (www.letpub.com) for its linguistic assistance during the preparation of this manuscript.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This work was supported by Chongqing Special Financial Funds Project [grant number 19511]; Special Project for Performance Guidance of Scientific Research Institution in Chongqing [grant number 19237] and China Agriculture Research System of MOF and MARA [grant number CARS-35].