No abstract

Domestic wastewater depth processing and reclamation are essential in the alleviation of global water shortage. In this study, an innovative filter media (i.e., Fe3O4@Carbon filter media [FCM]) was synthesized and subsequently used in a biological aerated filter (BAF) for simultaneous phosphate recovery and nitrogen removal (SPN) from domestic wastewater. The performance of FCM was compared with the commercially available ceramsite (CAC). The results showed that the performance of FCMBAF was better than that of CACBAF; as far as SPN is concerned, the magnetic field of FCMBAF could accelerate the growth rate of biofilm. Moreover, the nitrospira and nirK gene copy numbers of FCMBAF were considerably higher than those of CACBAF. Interestingly, the interconnectivity and uniformity of pores were also suitable for the microdistribution of biofilm, where different aerobic and anaerobic zones of the FCM were formed. This facilitates the microinteraction between the key microorganisms and the filter media that successfully enhanced the nitrogen removal. The phosphate recovery was attained via hydroxyapatite (Ca10(PO4)6(OH)2) formation, which resulted from the reaction between phosphate (PO4 3–) and FCM. The average effluent concentrations of total organic carbon (TOC), total nitrogen (TN), ammonia nitrogen (NH4 +-N), and PO4 3– were 8.12, 6.18, 0.997, and 0.073 mg/L of FCMBAF, respectively, which were lower than those from the national standard (CODcr ≤ 50 mg L–1, NH4 +-N ≤ 5.0 mg L–1, TN ≤ 15 mg L–1, TP ≤ 0.5 mg L–1, GB 18918–2002, first standard). Thus, FCM demonstrated a promising potential for SPN and wastewater recycling of BAF in domestic wastewater treatment.

Hydrodynamic cavitation can effectively remove organic pollutants and microorganisms from water. Organic compound degradation and water disinfection removal rate is related to reaction time and operating temperature. Removal rate can be improved by increasing the reaction time or raising the operating temperature. Under our experimental conditions, the removal rate of colority, COD and petroleum pollutants was 80.0%, 72.13% and 70.00%, respectively. In addition, Escherichia coli removal rate was higher than 99.99%. As a new water treatment process, hydrodynamic cavitation can be utilized alone or in combination with other water treatment processes, showing broad application prospects.

A simulation method was presented based on the theory analysis and ozone reaction equation. The preliminary mathematical models of ozonation correlative to oily pollutant removal were set up by numerical simulation. The ozonation models implied removal ratio of oil related to reaction time, ozone dosage and initial oil content. The simulation results were consistent with the experimental data.

A strain of Acidithiobacillus ferrooxidans designated S t1 was isolated and identified from the acid mine drainage of Tianmashan Coal Mine, Tongling county, Anhui province. Its morphological, physiological and biochemical characters, growth conditions of pH value and temperature, 16S rDNA sequence and the phylogenetic tree was studied. Results showed that the bacteria strains from different sites have divergence at the curve of pH and Eh values during the enriching culture. The isolated strain S t1 grew in a pH rang from 2.0 to 3.0 and temperature 25 to 35°C with over 98％similarity toAcidithiobacillus ferrooxidansin 16S rDNA sequence.