A cationic starch flocculant was prepared from potato peel waste (PPW) for enhanced solid-liquid separation of livestock wastewater, thereby promoting the agricultural circular economy. The starch extracted from PPW was...

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In this study, cationic cellulose (CC) was prepared by etherifying commercial cellulose with (3-chloro-2 hydroxypropyl) trimethylammonium chloride (CHPTAC) in an alkaline medium. The prepared CC was characterized using Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). The characterization results affirmed the successful cationization of cellulose. Upon optimization of reaction conditions, a CC sample with a degree of substitution (DS) of 0.857 was achieved. The CC sample was then tested as a flocculant or sorbent in three environmental applications: algal harvesting, solid removal from dairy wastewater, and capture of methyl orange (MO) in dye wastewater. The effects of dose level and pH on flocculation/sorption performance were studied. Under the optimal dose level and pH conditions, up to 90.4% of dry algal biomass and 53.3% of suspended solids in the dairy wastewater were removed, as measured by standard jar testing. Around 64.2% of MO in the synthetic wastewater was sorbed on the prepared CC and removed, as determined by absorbance at 463 nm. The new CC preparation method exempts the pre-dissolution of cellulose in a solvent and is expected to promote the application of CC in water treatment and the alike scenarios.

Particulate matter (PM) represents an air quality management challenge for confined swine production systems. Because of the limited space and ventilation rate, PM can reach relatively high concentrations in swine barns. PM in swine barns possesses different physical, chemical, and biological characteristics than that in the atmosphere and other indoor environments. As a result, it exerts different environmental and health effects and creates some unique challenges regarding PM measurement and mitigation. Numerous research efforts have been made, generating massive data and information. However, relevant review reports are sporadic. This study aims to provide an updated comprehensive review of swine barn PM, focusing on publications since 1990. It covers various topics, including PM characteristics, sources, measurement methods, and in-barn mitigation technologies. Since PM in swine barns is of primarily biological origins, bioaerosols are reviewed in great detail. Relevant topics include bacterial/fungal counts, viruses, microbial community composition, antibiotic-resistant bacteria, antibiotic resistance genes, endotoxins, and (1→3)-β-D-glucans. For each topic, existing knowledge is summarized and discussed and knowledge gaps are identified. Overall, PM in swine barns is complicated in chemical and biological composition and highly variable in mass concentrations, size, and microbial abundance. Feed, feces, and skins constitute the major PM sources. Regarding in-barn PM mitigation, four technologies (oil/water sprinkling, ionization, alternation of feed and feeders, and recirculating air filtration) are dominant. However, none of them have been widely used in commercial barns. A collective discussion of major knowledge gaps and future research needs is offered at the end of the report.