Objective The study aims to develop a practical, effective, simple and feasible wastewater treatment technology for Litopenaeus vannamei aquaculture, in order to promote the green and healthy development of the industry.
Methods On the basis of the traditional sulfur limestone autotrophic denitrification system (SLAD), an autotrophic denitrification system was composed of pyrite and volcanic rock. The wastewater of shrimp farming was taken as the research object to investigate the effect of different hydraulic retention times (HRT) on nitrogen and phosphorus removal in the system. The reactor was continuously operated for 40 days to observe the denitrification and phosphorus removal efficiency and stability of the system. The morphology and structure of the material surface were observed using scanning electron microscope (SEM), and the microbial community structure on the filler surface was analyzed using high-throughput sequencing.
Results The removal rate of nitrogen and phosphorus in the reactor increased with the increase of hydraulic retention time. By the end of the experiment, the removal rates of total nitrogen and total phosphorus remained stable at around 90% and 50%, respectively, with a pH value between 6.4 and 7.0. The microbial types on the surface of the system packing are mainly Thiobacillus and Halothobacillus, which are distributed in all four types of packing.
Conclusion The reactor exhibits efficient denitrification and phosphorus removal capabilities, with the autotrophic denitrification system based on pyrite emerging as a promising approach for treating aquaculture wastewater.
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