Evaluation of virus recovery methods and efficiency of tannin-derived coagulants in removing total coliforms, E. coli and enteric viruses in effluents of a domestic sewage treatment plant

Tannin-based coagulants: Current development and prospects on synthesis and uses

Population growth, industrialization, urbanization, and agriculture lead to a decrease in the availability of clean water. Coagulation/flocculation is one of the most common operations in water, urban wastewater, and industrial effluents treatment systems. Usually, this process is achieved using conventional coagulants that have their performance affected by pH, are poorly biodegradable, produce a huge volume of sludge, and are associated with degenerative diseases. As a substitute for these chemicals, natural coagulants have been highly researched for the last ten/fifteen years, especially the tannin-based (TB) ones. This review paper highlights the advantages of using these greener products to treat different types of water, wastewater, and effluents, especially from dairy, cosmetics, laundries, textile, and other industries. TB coagulants can successfully remove turbidity, color, suspended solids, soluble organic (chemical/biochemical oxygen demand) and inorganic matter (total phosphate, and heavy metals), and microorganisms. TB coagulants are compatible with other treatment technologies and can be used as coagulant-aid to reduce the consumption of chemicals. TB coagulants can reduce operating costs of water treatment due to less alkalinity consumption, as pH adjustment is sometimes unnecessary, and the production of a smaller volume of biodegradable sludge. TB coagulants can be synthesized by valorizing wastes/by-products, from the bark of some specific trees and skins/pomace of different fruits and vegetables. The strengths, weaknesses, opportunities, and threats (SWOT) on TB coagulants are discussed. The progress of TB coagulants is promising, but some threats should be overcome, especially on tannin extraction and cationization. The market competition with conventional coagulants, the feasibility of application in real waters, and the reluctance of the industries to adapt to new technologies are other weaknesses to be surpassed.

Analysis of four governance factors on efforts of water governing agencies to increase water reuse in the San Antonio Region

Securing sources for water reuse and coordinating efforts of water governing agencies to do so are critical to realizing the potential of reused water to provide nearly 24% of the water demand of the San Antonio Region, defined as regions "L" and "K" by the Texas Water Development Board (TWDB). This research identifies key governance factors that contribute to increasing water reuse within the water planning sector and tests four governance-related hypotheses for their impact on efforts to increase water reuse in the Region. Variables tested include: the type and scale of water governance agency, the agency's frequency of communication with the TWDB, and the agency's familiarity with the TWDB water strategy supplies as defined in the Texas State Water Plan of 2017. A questionnaire addressing these variables was sent to water governing agencies in regions L and K; the response rate was 39.5%. Each variable was cross-tabulated with agency efforts to increase water reuse. Seven regression analysis models were calculated among the factors to test for statistical significance and impact on increasing water reuse efforts. Results indicate that nearly 70% of agencies in the regions have efforts to increase water reuse by as much as 10%. Among the tested hypotheses, frequency in communication with the TWDB was statistically significant for increasing agency efforts to reuse water. Results from these hypotheses are expected to help water managers identify key, governance-related factors that contribute to increased water reuse.

Novel poly(ε-caprolactone)/amino-functionalized tannin electrospun membranes as scaffolds for tissue engineering

Poly(ε-caprolactone) (PCL) is a hydrophobic and cytocompatible aliphatic polyester that has been used to produce PCL-based nanofibrous for both wound healing and tissue repair. However, the high hydrophobicity and low water adsorptive have been challenges for developing PCL-based materials for use in tissue engineering field. Here, we report a new polymer (a hydrophilic amino-functionalized tannin (TN)) that is associated with PCL for developing PCL-TN blends at different PCL:TN weight ratios (100:0, 95:5, 85:15 and 78:22). PCL:TN ratio may be tuned to modulate hydrophilicity and cytocompatibility of the nanofibers. The neutralization step and surface wettability played an important role in the attachment of human adipose-derived stem cells (ADSC cells) on PCL-TN membranes. Also, fluorescence images confirmed great proliferation of ADSC cells on the PCL-TN electrospun surfaces. Yet, neutralized PCL-TN nanofibers promoted bactericidal activity against Pseudomonas aeruginosa. These membranes have potential to be used as scaffolds for tissue engineering purposes.