Dialysis as a new pre-treatment technique for online bacterial counting

Degradation of pesticide wastewater with simultaneous resource recovery via ozonation coupled with anaerobic biochemical technology

The effective treatment of pesticide wastewater with high organic content, complex composition and high-toxicity has attracted enormous attention of researchers. This work proposes a new idea for removing the pesticide wastewater with simultaneous resource recovery, which is different from the traditional view of mineralization of pesticide wastewater via composite technology. This novel strategy involved a sequential three-step treatment: (a) acidic Ozonation process, to remove the venomous aromatic heterocyclic compounds; (b) hydrolysis and ozonation in alkaline conditions, enhancing the biodegradability of pesticide wastewater, mainly due to the dehalogenation, elimination of C=C bonds and production of low molecular-weight carboxylate anions; (c) the final step is anaerobic biological reactions. Based on the characterizations, this two-stage acidic-alkaline ozonation can efficiently degraded the virulence of pesticide wastewater and enhance its biodegradability from 0.08 to 0.32. The final anaerobic biochemical treatment can stably remove the residuals and convert the low molecular-weight organics into CH₄, achieving the resource recovery. This work explored the pH-dependent of ozonized degradation of pesticide wastewater and gives a new perspective of wastewater treatment.

Online evaluation of bacterial cells in sand filter effluents during full-scale treatment of drinking water

Ensuring the microbiological safety of drinking water is critical to protect public health. This study aimed to evaluate the reliability of real-time bacteriological counter coupled with an online dialysis membrane-based pre-treatment system for continuously monitoring bacterial cell counts in sand filter effluents of a full-scale drinking water treatment plant. The pre-treatment system, which included anion exchange resins (porous polymeric microbeads that trap ions for releasing other ions) for dialysate regeneration, successfully achieved the stable attenuation of background interfering substances (humic acids) during the 19-d test. The real-time bacteriological counter equipped with the pre-treatment system provided a continuous profile of bacterial cell counts in the sand filter effluent (0.2-2.5 × 10⁴ counts/mL). The online analysis identified different timing of concentration peaks between particle and bacterial cell counts after backwashing. Bacterial community analysis revealed that Proteobacteria, Planctomycetes, and Cyanobacteria were the dominating phyla. Further, total bacterial cell counts determined by fluorescence microscopy and SYBR® Green I staining, a commonly accepted parameter, was found to be an indicator of online-monitored bacterial cell counts. The results indicated the potential of monitoring the bacterial cell counts in a sand filter process for providing an early warning of filter failures, which can allow plant operators to diagnose the overall system and provide countermeasures.

EGF-functionalized lipid-polymer hybrid nanoparticles of 5-fluorouracil and sulforaphane with enhanced bioavailability and anticancer activity against colon carcinoma

The present research work describes development of dual drug-loaded lipid-polymer hybrid nanoparticles (LPHNPs) of anticancer therapeutics for the management of colon cancer. The epidermal growth factor (EGF)-functionalized LPHNPs coloaded with 5-fluorouracil (FU) and sulforaphane (SFN) were prepared by one-step nanoprecipitation method. Box-Behnken design was applied for optimizing the material attributes and process parameters. The optimized LPHNPs revealed particle size 198 nm, polydispersity index 0.3, zeta potential -25.3 mV, and drug loading efficiency 19-20.3% for 5-FU and SFN, respectively. EGF functionalization on LPHNPs was confirmed from positive magnitude of zeta potential to 21.3 mV as compared with the plain LPHNPs. In vitro drug release performance indicated sustained and non-Fickian mechanism release nature of the drugs from LPHNPs. Anticancer activity evaluation in HCT-15 colon cancer cells showed significant reduction (p < 0.001) in the cell growth and cytotoxicity of the investigated drugs from various treatments in the order: EGF-functionalized LPHNPs > plain LPHNPs > free drug suspensions. Overall, the research work corroborated improved treatment efficacy of EGF-functionalized LPHNPs for delivering chemotherapeutic agents for the management of colon carcinoma.