Microwave effects on soluble substrate and thermophilic digestibility of activated sludge.

Thickened waste-activated sludge (TWAS) was subjected to microwave pretreatment and athermal irradiation. The soluble phase of each type of TWAS pretreatment was subject to ultrafiltration in series using progressively smaller pore-size membranes (300, 100, 10, and 1 kDa) and biodegradability tests. Microwave pretreatment solubilizes a considerable amount of the suspended organic substrate, but athermal irradiation also causes solubilization of organic matter, although at a smaller scale than microwave.

Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions.

Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.

Effect of enzymes on anaerobic digestion of primary sludge and septic tank performance.

Enzyme additives are believed to improve septic tank performance by increasing the hydrolysis and digestion rates and maintaining a healthy microbial population. Previous studies reported mixed results on the effectiveness of enzymes on mesophilic and thermophilic digestion, and it is not clear whether enzymes would be effective under septic tank conditions where there is no heating or mixing, quantities of enzymes added are small, and they can be washed out quickly. In this study, batch reactors and continuous-flow reactors designed and operated as septic tanks were used to evaluate whether enzymatic treatment would increase the hydrolysis and digestion rates in primary sludge.

Effect of leachate recirculation on mesophilic anaerobic digestion of food waste.

The effects of using untreated leachate for supplemental water addition and liquid recirculation on anaerobic digestion of food waste was evaluated by combining cyclic water recycle operations with batch mesophilic biochemical methane potential (BMP) assays. Cyclic BMP assays indicated that using an appropriate fraction of recycled leachate and fresh make up water can stimulate methanogenic activity and enhance biogas production. Conversely increasing the percentage of recycled leachate in the make up water eventually causes methanogenic inhibition and decrease in the rate of food waste stabilization.

Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide.

In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H(2)O(2)) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion.

Mesophilic anaerobic digestion with high-temperature microwave pretreatment and importance of inoculum acclimation.

Thickened waste activated sludge (TWAS) was pretreated with microwave irradiation to temperatures higher than the boiling point (between 110 and 175 degrees C) using different microwave intensities. Biochemical methane potential (BMP) assays demonstrated that, although mesophilic anaerobic digestion (MAD) inoculum used was acclimated for 4 months with microwave pretreated TWAS (to 175 degrees C), acute methanogenic inhibition was observed. Additionally, the microwave conditions applied increased the soluble chemical oxygen demand (sCOD)-to-total COD (tCOD) ratio; however, no significant enhancement in the rate or extent of TWAS stabilization was observed for the microwave-pretreated samples.

Evaluation of continuous mesophilic, thermophilic and temperature phased anaerobic digestion of microwaved activated sludge.

The effects of microwave (MW) pretreatment, staging and digestion temperature on anaerobic digestion were investigated in a setup of ten reactors. A mesophilic reactor was used as a control. Its performance was compared to single-stage mesophilic and thermophilic reactors treating pretreated and non-pretreated sludge, temperature-phased (TPAD) thermophilic-mesophilic reactors treating pretreated and non-pretreated sludge and thermophilic-thermophilic reactors also treating pretreated and non-pretreated sludge.

Anaerobic digestion of whole stillage from dry-grind corn ethanol plant under mesophilic and thermophilic conditions.

Anaerobic digestion of whole stillage from a dry-grind corn-based ethanol plant was evaluated by batch and continuous-flow digesters under thermophilic and mesophilic conditions. At whole corn stillage concentrations of 6348 to 50,786 mg total chemical oxygen demand (TCOD)/L, at standard temperature (0 °C) and pressure (1 atm), preliminary biochemical methane potential assays produced 88±8 L (49±5 L CH4) and 96±19 L (65±14 L CH4) biogas per L stillage from mesophilic and thermophilic digesters, respectively. Continuous-flow studies for the full-strength stillage (TCOD=254 g/L) at organic loadings of 4.

Enhanced solubilization and anaerobic biodegradability of source-separated kitchen waste by microwave pre-treatment.

Results from an investigation of the effect of high temperature and pressure microwave (MW) pre-treatment of source-separated kitchen waste (SSKW) are presented. MW pre-treatment to a temperature of 175 °C (1 min holding time) at a heating rate of 7.9 °C min(-1), enhanced SSKW solubilization by 40% in comparison with control; yielding higher soluble chemical oxygen demand (sCOD), total sugars and proteins concentrations in the soluble phase (<45 μm).

Effect of microwave irradiation on anaerobic degradability of model kitchen waste.

High temperature and pressure microwave (MW) irradiation was investigated as a pre-treatment to enhance anaerobic biodegradability and methane production from a model kitchen waste (KW). Heating rates of 7.8, 3.

Characterization of an anaerobic baffled reactor treating dilute aircraft de-icing fluid and long term effects of operation on granular biomass.

Successful treatment of dilute ethylene glycol based-aircraft de-icing fluid (ADF) was achieved using a four compartment, anaerobic baffled reactor (ABR). Three ADF concentrations (0.04, 0.

Effect of low temperature microwave pretreatment on characteristics and mesophilic digestion of primary sludge.

The main obstacles existing in the biodegradation of primary sludge are particle de-amalgamation and the degradation-resisting structure of large-size particulate. Microwave irradiation solubilizes primary sludge by interaction of the electromagnetic field with polar particles in the sludge, which leads to a temperature increase in the irradiated sample. The influence of microwave irradiation on the characteristics and biochemical methane potential of microwave-pretreated primary sludge was studied in terms of microwave intensity (40 and 80% of total microwave power), sludge solid concentration (1 to 4% total solids, w/v) and pretreatment temperature achieved (35 to 90 degrees C).

Evaluation of continuous mesophilic anaerobic sludge digestion after high temperature microwave pretreatment.

Effect of microwave pretreatment (MW) high temperature (175 degrees C) and MW intensity to waste activated sludge digested with acclimatized inoculum in single- and dual-stage semi-continuous mesophilic anaerobic digesters at different sludge retention times (SRTs) (20, 10 and 5 days) were investigated. MW pretreatment led to similar sludge stabilization at low SRTs (5 and 10 days). Although lowering MW intensity slightly improved sludge solubilization, it had a negative effect on digestion at low SRTs.

Synergetic pretreatment of sewage sludge by microwave irradiation in presence of H2O2 for enhanced anaerobic digestion.

A microwave-enhanced advanced hydrogen peroxide oxidation process (MW/H(2)O(2)-AOP) was studied in order to investigate the synergetic effects of MW irradiation on H(2)O(2) treated waste activated sludges (WAS) in terms of mineralization (permanent stabilization), sludge disintegration/solubilization, and subsequent anaerobic biodegradation as well as dewaterability after digestion. Thickened WAS sample pretreated with 1gH(2)O(2)/g total solids (TS) lost 11-34% of its TS, total chemical oxygen demand (COD) and total biopolymers (humic acids, proteins and sugars) via advanced oxidation. In a temperature range of 60-120 degrees C, elevated MW temperatures (>80 degrees C) further increased the decomposition of H(2)O(2) into OH* radicals and enhanced both oxidation of COD and solubilization of particulate COD (>0.

Enhancement of batch waste activated sludge digestion by microwave pretreatment.

Batch anaerobic digesters were used to stabilize microwave (MW)-irradiated waste activated sludge (WAS). A low temperature range (50-96 degrees C) MW irradiation was applied. Effects of pretreatment temperature (T) and intensity (I), concentration (C) and percentage of sludge pretreated (PT) were investigated in a multilevel factorial statistical design containing 54 mesophilic batch reactors by monitoring cumulative biogas production (CBP).

Performance of anaerobic waste activated sludge digesters after microwave pretreatment.

Effects of microwave pretreatment on waste activated sludge (WAS) in mesophilic semicontinuous digesters with acclimatized inoculum at solids retention times (SRTs) of 5, 10, and 20 days are presented. Batch digesters determined optimum microwave temperature, intensity, WAS concentration, and percentage of WAS pretreated for highest WAS solubilization (soluble to total chemical oxygen demand ratio [SCOD:TCOD]) and biogas production. Pretreatment results indicated the potential to damage floc structure and release 4.

Athermal microwave effects for enhancing digestibility of waste activated sludge.

A bench scale industrial microwave (MW) unit equipped with fiber optic temperature and pressure controls within pressure sealed vessels successfully simulated conventional heating (CH, in water bath). By identical temporal heat temperature profiles for waste activated sludge (WAS) samples, evaluation of the athermal effects of MW irradiation on WAS floc disintegration and anaerobic digestion was achieved. In a pretreatment range of 50-96 degrees C, both MW and CH WAS samples resulted in similar particulate chemical oxygen demand (COD) and biopolymer (protein and polysaccharide) solubilization and there was no discernable MW athermal effect on the COD solubilization of WAS.

Characterization of soluble organic matter of waste activated sludge before and after thermal pretreatment.

Microwave (MW) irradiation and conventional heating (CH) at 96 degrees C was successful in disrupting the complex waste activated sludge (WAS) floc structure and releasing extra- and intra-cellular biopolymers, such as protein and sugars from activated sludge flocs into soluble phase along with solubilization of particulate chemical oxygen demand (COD). Soluble CODs of CH and MW-irradiated WAS were 361+/-45% and 143+/-34% higher and resulted in 475+/-3% and 211+/-2% higher cumulative biogas productions (CBP) relative to the control at the end of 23 days of mesophilic anaerobic digestion, respectively. Ultrafiltration (UF) was used to characterize the soluble molecular weight (Mw) distributions of control (unpretreated), CH and MW-irradiated WAS.

Anti-CCL2 treatment inhibits Theiler's murine encephalomyelitis virus-induced demyelinating disease.

Theiler's murine encephalomyelitis virus induces a demyelinating disease (TMEV-IDD) of the central nervous system (CNS) in susceptible mouse strains with accompanying histopathology characterized by mononuclear cell infiltrates. In susceptible strains of mice such as SJL, virus establishes a persistent infection in macrophages, induces a CNS infiltration by macrophages, T cells, and B cells, which results in chronic-progressive paralysis. In the present report the authors have investigated the functional role of CCL2 (monocyte chemotactic protein-1) in the induction and progression of demyelinating disease.

Transgenic expression of CCL2 in the central nervous system prevents experimental autoimmune encephalomyelitis.

CC chemokine ligand 2 (CCL2)/monocyte chemotactic protein-1, a member of the CC chemokine family, is a chemoattractant for monocytes and T cells through interaction with its receptor CCR2. In the present study, we examined a T helper cell type 1 (Th1)-dependent disease, proteolipid protein-induced experimental autoimmune encephalomyelitis, in a transgenic mouse line that constitutively expressed low levels of CCL2 in the central nervous system (CNS) under control of the astrocyte-specific glial fibrillary acidic protein promoter. CCL2 transgenic mice developed significantly milder clinical disease than littermate controls.

Immunoneutralization of chemokines for the prevention and treatment of central nervous system autoimmune disease.

Chemokine-induced lymphocyte migration has long been hypothesized to regulate the appearance and continued presence of lymphocytes and monocytes in tissue-specific autoimmune diseases, including central nervous system autoimmune diseases such as multiple sclerosis. For instance, a large body of evidence points to the temporal association of chemokine expression with the appearance of T lymphocytes and monocytes/macrophages. Furthermore, experiments using mice with targeted mutations for chemokines have shown the importance of those molecules in the development of central nervous system autoimmune disease.

Anomalous differences of light elements in determining precise binding modes of ligands to glycerol-3-phosphate dehydrogenase.

Pathogenic protozoa such as Trypanosome and Leishmania species cause tremendous suffering worldwide. Because of their dependence on glycolysis for energy, the glycolytic enzymes of these organisms, including glycerol-3-phosphate dehydrogenase (GPDH), are considered attractive drug targets. Using the adenine part of NAD as a lead compound, several 2,6-disubstituted purines were synthesized as inhibitors of Leishmania mexicana GPDH (LmGPDH).

Regulation of experimental autoimmune encephalomyelitis by chemokines and chemokine receptors.

Experimental autoimmune encephalomyelitis (EAE) is a T cell mediated demyelinating disease of the central nervous system (CNS) that serves as a model for multiple sclerosis (MS). Insights into the pathogenesis of this model may help scientists understand the human disease and aid in rational drug discovery. In this review we summarize the role of chemokines and chemokine receptors in disease pathogenesis and suggest a pathway of events that leads to demyelination and subsequent clinical disease manifestation.

Chemokine Regulation of Immune-mediated Demyelinating Disease.

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ Th1-mediated demyelinating disease of the central nervous system (CNS), which serves as a model for multiple schlerosis (MS). A hallmark in the pathogenesis of this disease is the emigration of T cells and monocytes from the blood to the CNS. Chemokines are small-molecular-weight chemotactic peptides, which are ligands for seven transmembrane-spanning, G protein-coupled receptors and which deliver signals leading to a variety of T cell functions including costimulation, cytokine expression, differentiation, and integrin activation.