Degradation of Decabromodiphenyl Ether in an Aerobic Clay Slurry Microcosm Using a Novel Immobilization Technique.

A novel chitosan immobilization technique that entraps photocatalyst and microbes was developed and applied to decompose decabromodiphenyl ether (BDE-209) in a clay slurry microcosm. The optimized conditions for immobilization were obtained by mixing 1.2% (w/v) chitosan dissolved in 1% (v/v) acetic acid with nano-TiO2 particles and the BDE-209-degrading bacterial mixed culture. This aqueous mixture was injected into 1% (w/v) water solution containing sodium tripolyphosphate to form spherical immobilized beads. The surface of the immobilized beads was reinforced by 0.25% (v/v) glutaraldehyde cross-linking. These beads had enough mechanical strength during BDE-209 degradation to maintain their shape in the system at a stirring rate of 200-rpm, while undergoing continuous 365 nm UVA irradiation. This novel TiO2-Yi-Li immobilized chitosan beads system allowed a successful simultaneous integration of photolysis, photocatalysis and biodegradation to remove BDE-209. The remaining percentage of BDE-209 was 41% after 70 days of degradation using this system. The dominant bacteria in the BDE-209-degrading bacterial mixed culture during remediation were Chitinophaga spp., Methyloversatilis spp., Terrimonas spp. and Pseudomonas spp. These bacteria tolerated the long-term UVA irradiation and high-level free radicals present, while utilizing BDE-209 as their primary carbon resource. This new method has great potential for the treatment of a range of pollutants.

An Investigation of Airborne Bioaerosols and Endotoxins Present in Indoor Traditional Wet Markets before and after Operation in Taiwan: A Case Study.

Customers in Taiwan prefer to purchase fresh foods and household supplies at indoor traditional wet markets (TWMs). The health risk to indoor TWM staff exposed to bioaerosols needs to be evaluated, since these workers spend long periods of time in the market for stall preparation, selling, and stall cleaning. This study investigated the bioaerosols present in two indoor TWMs. The results showed that the cleaning process at Market A after operations, involving the use of an agitated waterspout, was able to decrease the concentration of bacterial bioaerosols (BBs) by an average of 64%, while at the same time increasing the concentration of fungal bioaerosols (FBs) by about 2.4 fold. The chemical sanitization process at Market B after operations was able to bring about average decreases of 30.8% in BBs and 19.2% in FBs, but the endotoxin concentration increased. Hotspots were found to be associated with vendors of fresh, live poultry and fresh, raw meat/seafood. Pseudomonas spp. and Clostridiumperfringens, both of which can be pathogenic, were found to be the dominant species present in these markets, making up 35.18% to 48.74% and 9.64% to 11.72% of the bacteria present, respectively. Our results provide fundamental information on the distributions of bioaerosols and endotoxins within indoor TWMs both before and after operation.

The treatment of PPCP-containing sewage in an anoxic/aerobic reactor coupled with a novel design of solid plain graphite-plates microbial fuel cell.

Synthetic sewage containing high concentrations of pharmaceuticals and personal care products (PPCPs, mg/L level) was treated using an anoxic/aerobic (A/O) reactor coupled with a microbial fuel cell (MFC) at hydraulic retention time (HRT) of 8 h. A novel design of solid plain graphite plates (SPGRPs) was used for the high surface area biodegradation of the PPCP-containing sewage and for the generation of electricity. The average CODCr and total nitrogen removal efficiencies achieved were 97.20% and 83.75%, respectively. High removal efficiencies of pharmaceuticals, including acetaminophen, ibuprofen, and sulfamethoxazole, were also obtained and ranged from 98.21% to 99.89%. A maximum power density of 532.61 mW/cm(2) and a maximum coulombic efficiency of 25.20% were measured for the SPGRP MFC at the anode. Distinct differences in the bacterial community were presented at various locations including the mixed liquor suspended solids and biofilms. The bacterial groups involved in PPCP biodegradation were identified as Dechloromonas spp., Sphingomonas sp., and Pseudomonas aeruginosa. This design, which couples an A/O reactor with a novel design of SPGRP MFC, allows the simultaneous removal of PPCPs and successful electricity production.