Soluble microbial products (SMP) and soluble extracellular polymeric substances (EPS) from wastewater sludge.

Laspidou and Rittmann (Water Research 36:2711-2720, 2002) proposed that the soluble extracellular polymeric substances (EPS) are identical to soluble microbial products (SMP) in sludge liquor. In this paper, we compared the physicochemical characteristics of the SMP and soluble EPS from original and aerobically or anaerobically digested wastewater sludge. The surface charges, particle sizes, residual turbidities of polyaluminum chloride (PACl) coagulated supernatant, and chemical compositions of the SMP and soluble EPS containing suspensions were used as comparison index.

In situ distributions and characteristics of heavy metals in full-scale landfill layers.

The leachate from methanogenic landfill normally contains low concentrations of heavy metals. Little samples had ever been collected from the full-scale landfill piles owing to technical difficulty for well drilling. We drilled two wells in Hangzhou Tianziling landfill, 20 m and 32 m in depth each, and collected solid samples of waste age of 1-4 years from both wells.

Dissolved organic matter (DOM) in recycled leachate of bioreactor landfill.

Landfill leachate needs sufficient treatment before safe disposal. Bioreactor landfill technology could effectively degrade the organic matters in recirculated leachate, hence leaving a leachate stream of low biodegradability. This study characterized the dissolved organic matter (DOM) in the leachate from simulated bioreactor landfill columns with or without presence of trace oxygen.

In vitro and in vivo release of gentamicin from biodegradable discs.

Osteomyelitis is an infection of the bone and successful treatment involves the removal of the affected bone and the tissue by a surgical procedure following prolonged systemic and local antibiotic therapy for 4 to 6 weeks. The current local treatment is done by poly methyl methacrylate (PMMA) beads loaded with gentamicin and PMMA, being nondegradable, is to be removed by a second surgical procedure. The current study aims to develop a biodegradable composition that gives sustained release and hence reducing the need for a second surgery.

Leaching of carbonated air pollution control residues using compliance leaching tests.

The leaching characteristics of air pollution control (APC) residues collected in Shanghai, China, were compared by performing three compliance leaching tests. These were the standard Chinese method for determining the leaching toxicity of solid waste (GB 5086.1-1997), the USEPA's Toxicity Characteristic Leaching Procedure (TCLP), and the new European shake test (EN 12457-3).

Enzymatic hydrolysis of polysaccharide-rich particulate organic waste.

Hydrolysis of organic particulates in rapid fermentative processes can be inhibited. The volatile fatty acids (VFA) released during fermentation reduce pH. Whether VFA or the drop in pH inhibits hydrolysis is unclear.

Landfill leachate treatment in assisted landfill bioreactor.

Landfill is the major disposal route of municipal solid waste (MSW) in most Asian countries. Leachate from landfill presents a strong wastewater that needs intensive treatment before discharge. Direct recycling was proposed as an effective alternative for leachate treatment by taking the landfill as a bioreactor.

Cake consolidation in a compression-permeability cell: effect of side-wall friction.

A simulation study was made to investigate the transient state stresses, strains, and void ratio distributions in the formation of a filter cake in a compression-permeability cell (C-P cell). A finite-element software package, ABAQUS, was used for the simulation and emphasis was placed on the effect of the cake/cell-surface friction. The validity of the simulation was assessed by comparing simulation results with available experimental data.

Drag on two coaxial, nonuniformly structured flocs in a uniform flow field.

The drag on two coaxial flocs of nonuniform structure in a Newtonian fluid is evaluated for Reynolds number ranges from 0.1 to 40. A two-layer model is adopted to simulate various possible structures of a floc.

Aging of air pollution control residues from municipal solid waste incinerator: role of water content on metal carbonation.

This work studies the effect of water content on the aging of APC residues, with a liquid to solid ratio (L/S) of 0.25 or 10, aged with or without exposure to ambient air. After the residue was mixed with water, CaSO4 and (Na,K)Al3(SO4)2(OH)6 in the raw sample yielded ettringite.

Effects of feed solutions on refuse hydrolysis and landfill leachate characteristics.

Tap water, aerobically pre-treated leachate, and anaerobically pre-treated leachate, were each fed into the top of a series of three simulated landfills columns, filled with municipal solid waste collected in Shanghai, China. Changes in leachate, including pH, total organic carbon (TOC), and volatile fatty acids (VFAs), and the produced biogas were monitored over time. The tap-water-fed columns had a low hydrolysis rate that yielded an acidic environment (pH 4.

Gentamicin-loaded discs and microspheres and their modifications: characterization and in vitro release.

Osteomyelitis is an infection of the bone, and successful treatment involves local administration for about 6 weeks. Gentamicin is a very hydrophilic drug and tends to come out into the water phase when microspheres are fabricated using solvent evaporation method. Hence, spray drying is an option, and it was observed that the release rate tends to be fast when the particle size is small and large particles cannot be prepared by spray drying.

Characteristics of air pollution control residues of MSW incineration plant in Shanghai.

A unique type of waste--air pollution control (APC) residues--has received increasing attention in China since the first large-scale incinerator, Shanghai Yuqiao municipal solid waste (MSW) incineration plant, was installed in the country in 2002. The APC residues of this particular plant are similar to other residues that will be produced in other incineration plants under construction in China. This work examines for the first time the benchmark contaminants of APC residues from the Yuqiao Plant, with reference to soluble salts, heavy metals and dioxins.

Plastic deformation in cake consolidation.

Cake filtration has a variety of applications in wastewater treatment by solid/liquid separation processes. In order to obtain the physical properties of the filter cake, a Compression-Permeability Cell (C-P Cell) can be used to examine the constitutive relationships among the solid compressive stresses, porosity and the specific filtration resistance. In this paper, a mathematical model is proposed to study the transient distribution of stresses, strains and void ratios in the confined cake of a C-P Cell under constant axial loads for dewatering.

Microbiological degradation of phenol using mixed liquors of Pseudomonas putida and activated sludge.

This work investigated the biodegradation potential of phenol using mixed liquors of Pseudomonas putida (ATCC 31800) and activated sludge. Experiments were made as a function of solution pH (6-10), temperature (30-36 degrees C), nitrogen source (NH4)2SO4 (0.5-0.

Biodegradation and adsorption of phenol using activated carbon immobilized with Pseudomonas putida.

This paper examined the removal efficiency of phenol from aqueous solution using a suspended culture of Pseudomonas putida (ATCC 3180) or the activated carbon on which the microorganism was immobilized. The kinetics of phenol degradation by immobilized and pure cells was studied. Experiments were performed at various phenol concentrations (0.

Use of cellulose-based wastes for adsorption of dyes from aqueous solutions.

Low-cost banana and orange peels were prepared as adsorbents for the adsorption of dyes from aqueous solutions. Dye concentration and pH were varied. The adsorption capacities for both peels decreased in the order methyl orange (MO) > methylene blue (MB) > Rhodamine B (RB) > Congo red (CR) > methyl violet (MV) > amido black 10B (AB).

Factor optimization for phenol removal using activated carbon immobilized with Pseudomonas putida.

Removal efficiency of phenol from aqueous solutions was measured using a suspended culture of Pseudomonas putida (ATCC 3180) or the activated carbon on which the microorganisms were immobilized. Experiments were performed as a function of pH (7-9), temperature (30-36 degrees C), and concentrations of glucose (0.5-0.