Purification Effect of the Aquaculture Wastewater and Sediment by Microbial Nanospheres with Different Material Ratios and Dosing Methods

Yalu Shao,Liangkai Wang,Mohammed M.A Elbashier,Hua Zhong

doi:10.3390/su12041462

Abstract

Nanospheres were prepared by different materials of nano-bamboo charcoal powder, zeolite powder, and aquaculture pond sediment in different ratios. It was then fermented with effective microorganisms (EM) active calcium liquid to synthesize the bioactive microbial nanospheres. These nanospheres were used to compare the purification effect of ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) pollutants in aquaculture wastewater. The indoor simulation experiment was also conducted to compare the different dosage methods (one-time dosing without aeration, multiple dosing without aeration, and multiple dosing with aeration) of microbial nanospheres on the removal of organic matter (OM) and effect of the biodegradability (G value) in aquaculture sediment. The results obtained indicated that the purification effect was most remarkable when the mass ratio of nano-bamboo charcoal powder: zeolite powder: pond sediment was 10%: 15%: 75%, in which the maximum removal rate of NH4+-N, TN, and TP reached up to 84.86%, 52.15%, and 50.35%, respectively. Under the same microbial nanospheres amount, the effect of one-time addition on the removing of OM in sediment was not as effective as that of multiple dosing. After the 20th day, the removal rate of OM reached 25.99% in multiple dosing treatment and it was 35.58% higher than one-time dosing treatment. The OM content in sediment was reduced by 32.38% under the multiple dosing with aeration treatment. Multiple dosing of microbial nanospheres with aeration increased the G value of sediment about 337.0%. In situ experiment further indicated that the microbial nanospheres dosage with aeration had a good sediment bio-remediation effect, which is applicable to solve the problem of endogenous pollution in aquaculture ponds.

Highlights

IntroductionOver 80% of aquaculture has adopted an intensive cultivation pattern, large quantities of nitrogen and phosphorus are produced during the metabolism of aquatic animals, and the decomposition of excessive feed residues in the aquaculture [1]
China is the largest aquaculture country in the world
The results showed that the microbial nanospheres could purify NH4+-N and total nitrogen (TN) in aquaculture wastewater and the difference in removal effect was caused by the different proportion of nano bamboo charcoal (NBC) powder in the carrier

Summary

Introduction

Over 80% of aquaculture has adopted an intensive cultivation pattern, large quantities of nitrogen and phosphorus are produced during the metabolism of aquatic animals, and the decomposition of excessive feed residues in the aquaculture [1]. The food chain is frequently destroyed during the intensive aquaculture cultivation process, and a lot of organic matter from the residual bait, excrement, and death debris cannot be used by other organisms and remain in the bottom mud, which leads to the ecological degradation and the serious diseases [3]. A new type of circulating water pond model is applied to reduce the nitrogen and phosphorus content in the aquaculture water, mainly relying on aquatic plants and microbes function [8]. Liu [14] showed that the removal rates of TN and the TP were increased by 43.33% and 42.78%, and 54.80% and 53.77%, respectively, by using EM combined with two kinds of terrestrial plants to purify tail water compared with the common aquatic plant

Methods

Results

Conclusion