Effects of ceramsite derived from sewage sludge combined with the O3-FeCl3/PAM process on the dewatering of waste-activated sludge and investigation of dewatering mechanisms.

The high water content of waste-activated sludge restricts the subsequent disposal of sludge. The dehydration properties of O3, ferric chloride (FeCl3)/polyacrylamide, and sludge ceramsite sand (SCS) were studied. Simultaneously, the effect of combining the three was investigated to support the deep dehydration of waste-activated sludge. Experimental results showed that with13.42 mg/(g dry solids (DS)) of O3, 109.89 mg/(g DS) of FeCl3, and 100 mesh dosage of 70% DS of sludge ceramsite on weight, the highest sludge net yield was 7.13 kg/(m2·h) and the minimum specific resistance to filtration of sludge cake was 1.02 × 1012 (m/kg). Compared with the compressibility of the raw sludge, the compressibility of the sludge cake decreased by 37.48%. Moreover, the YN (net yield) increased by 73.55%. The results demonstrate that the structure of cracking, flocculation, and hydrophobic framework is the mechanism of sludge dewatering in this combined process. This combined treatment process provides a new perspective for the realization of deep dewatering of sludge and is anticipated to be a successful sludge dehydration method.

[Single nucleotide polymorphism of FCGR2A gene in Han Chinese children with Kawasaki disease].

OBJECTIVE: To study the association of FCGR2A gene single nucleotide polymorphism (SNP) rs1801274 with Kawasaki disease (KD) susceptibility and the efficacy of intravenous immunoglobulin (IVIG) therapy in Han Chinese children. METHODS: Thirty-five KD children and 25 age-and gender-matched healthy children (control group) were enrolled in the study. Polymerase chain reaction (PCR) and gene sequence analysis were applied to detect SNP of FCGR2A gene rs1801274. These KD patients were classified into two subgroups based on the presence of coronary artery lesion (CAL) following IVIG therapy: CAL (n=13) and non-CAL (n=22). RESULTS: FCGR2A gene SNP rs1801274 was detected in all subjects, including three genotypes (AA, AG and GG). For FCGR2A gene SNP rs1801274, there were significant differences in the genotype and allele frequencies between the KD and control groups (P<0.05), and significant differences in the genotype and allele frequencies were also found between the CAL and non-CAL subgroups (P<0.05). A allele and AA genotype were linked to an increased risk of KD susceptibility (A allele: OR=3.39, 95%CI:1.53-7.50; AA genotype: (OR=4.93, 95%CI:1.61-15.1). Both AG (OR=5.43, 95%CI:1.06-27.8) and G allele (OR=4.88, 95%CI:1.44-16.5) were linked to an increased risk of CAL in KD children. CONCLUSIONS: Polymorphism of the FCGR2A gene SNP rs1801274 is one of the important factors probably influencing susceptibility to KD and efficacy of IVIG therapy on KD in Han Chinese children.