Aerobic Biological Treatment of a Pharmaceutical Wastewater: : Effect of Temperature on COD Removal and Bacterial Community Development

The effect of temperature was studied on the efficiency of soluble COD removal and bacterial community development during the aerobic biological treatment of a pharmaceutical wastewater. Using wastewater and bacterial inoculum obtained from the full-scale facility treating this wastewater, batch laboratory cultures were operated at 5°C intervals from 30°C to 70°C. Following four culture transfers to allow for bacterial acclimation, residual soluble COD levels were measured and bacterial community fingerprints were obtained by denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified 16S rRNA gene fragments. Soluble COD removal efficiency declined as temperature increased from 30°C (62%) to 60°C (38%). Biological treatment of this wastewater failed to occur at temperatures higher than 60°C. Gradual shifts in bacterial community structure were detected as temperature increased, including a concomitant reduction in the number of different bacterial populations. The impact of temperature on a two-stage biological treatment process was also compared. Better soluble COD removal was achieved when both reactors were operated at 30°C compared to a system where the two stages were consecutively operated at 55°C and 30°C. These results indicate that operation of aerobic biological wastewater treatment reactors at elevated temperatures can have adverse effects on process performance.     

Cometabolic transformation of linear alkylbenzenesulphonates by methanotrophs

Cometabolic transformation of commercial linear alkylbenzenesulphonates (LAS) and pure congeners of 2-[4-(sulphophenyl)]nonan (2C₉LAS) and 2-[4-(sulphophenyl)]decan (2C₁₀LAS) was studied by using a mixed methanotrophic-heterotrophic culture MM1 and a pure culture of type II methanotroph (strain CSC1), isolated from culture MM1. Cultures were grown in shake flasks under conditions promoting expression of the soluble methane monooxygenase (sMMO). Both the mixed culture MM1 and the pure culture CSC1 were capable of transforming LAS with or without methane as the natural substrate. Experiments performed without methane (resting cells) showed faster cometabolic transformation of LAS congeners with longer alkyl side-chains. Both 2C₉LAS and 2C₁₀LAS congeners were transformed significantly faster at 30°C, although the optimum temperature for the growth of mixed culture MM1 was 20°C. Simultaneous methane oxidation and LAS transformation, and their mutual competitive inhibition, indicated the involvement of the MMO enzyme system and possible methanotrophic activity in the initiation of cometabolic LAS transformation. The capability of two heterotrophic species to transform sulphophenyldecanoic acid suggests possible heterotrophic activity in further LAS transformation (β-oxidation). Faster LAS transformation by mixed culture MM1 than by pure culture CSC1 suggested that methanotrophic-heterotrophic interactions are important for transformation of the complex LAS molecule.     

Micro-organisms and manganese cycling in a seasonally stratified freshwater dam

This work describes investigations into the role that biotic and abiotic mechanisms play in the manganese redox cycle in a freshwater dam over a twelve month period. Enzymatic control of manganese oxidation was taking place with a temperature optimum of approx. 30°C. Manganese oxidation was only significant above about 19°C. The temperature and season play vital roles in determining the extent to which abiotic and microbial mechanisms contribute to manganese oxidation. Results showed that microbial catalysis is overwhelmingly responsible for manganese oxidation in the lower epilimnion from November to May. Significant abiotic catalysis (up to 25%) can occur in late summer/autumn when the water temperature is greatest. Mn(II) oxidation, pseudo-first order rate constants to 1.12 × 10²² M⁻⁴ · d⁻¹ were measured while poisoned sample experiments confirmed the role of biological mediation. In winter, biological control could not occur because of the lower temperature of the water column. The measurement of “x” in MnO_x showed that higher manganese oxidation states were expected when the manganese oxidation rate was at a maximum and therefore when microbial activity was greatest. Direct microbial reduction of MnO_x in the water column was of much less significance. However, indirect reduction may have taken place through the reaction of MnO_x with sulfide. The results of this work have important implications for the design and operation of artificial destratification units for the control of manganese speciation.     

Optimum use of solar energy techniques in a semi-underground house: First-year measurement and computer analysis

In order to obtain fundamental information on techniques for the optimum use of solar energy in a semi-underground house, a twin-type test house was constructed on the campus of Tohoku University in September 1984. The test house has two rooms, with a south-facing window above the ground surface and a corridor situated between the two rooms. Insulation 10 cm deep and 1.35 m wide was installed horizontally 30 cm below the ground surface, surrounding one room of the house. The other room is not insulated. During the first year, all windows were insulated with weather shutters to avoid disturbing the heat gain due to solar radiation. As a result, the yearly room temperature swing varied °C less than the temperature swing of outdoor air. The air temperature in the insulated room was 1.2°C higher in the winter and 0.5°C lower in the summer than in the room without insulation. The influence of various thermal insulation formations in the earth around the house on room temperature fluctuation and heating and cooling loads was calculated using the two-dimensional finite element method. Calculations were performed hourly for a year under standard climate conditions in Sendai, Japan.     

Influence of temperature and substrate shocks on survival and succinic dehydrogenase activity of heterotrophic freshwater bacteria

The influence of temperature shocks on aquatic bacteria was studied in laboratory experiments with regard to population shifts in lake water communities of aerobic heterotrophic bacteria including coliforms. as well as in synthetic mixed cultures of psychrotolerant aquatic isolates. In addition, succinic dehydrogenase activity was used as a parameter of bioactivity. Each experiment was designed to study concomitant effects of elevated levels of organic substrates.

Simultaneous additions of complex nutrients such as 100–300 mg 1⁻¹ of meat peptone to lake water caused a synergistic action of substrate and temperature on population dynamics by depressing population densities at temperatures below 20°C. In contrast, stimulation was observed at higher temperatures particularly for the coliform group. In mixed cultures consisting of Cytophaga, Chromobacterium and Arthrobacter as important members of the heterotrophic microflora of the investigated lake water, substrate accelerated death was induced by temperature shocks beyond the maximum growth temperatures. The succinic dehydrogenase activity of a psychrotolerant strain of Cytophaga failed to show more sensitive responses to temperature shocks than did viable counts.     

Observations of upper-extremity skin temperature and corresponding overall-body thermal sensations and comfort

This paper explores how upper extremity skin temperatures correlate with overall-body thermal sensation. Skin temperature measurements of the finger, hand, and forearm might be useful in monitoring and predicting people's thermal state. Subjective perceptions of overall thermal sensation and comfort were collected by repeated surveys, for subjects in a range of test chamber temperatures. A positive temperature gradient (finger warmer than the forearm) of as much as 2 K was seen when subjects felt warm and hot, while a negative temperature gradient (finger colder than the forearm) as much as 8.5 K was seen for cool and cold subjects. A useful warm/cold boundary of 30 °C was found in finger temperature, for both steady state and transient conditions. When finger temperature was above 30 °C, or finger-forearm skin temperature gradient above 0 K, there was no cool discomfort. When finger temperature was below 30 °C, or the finger-forearm skin temperature gradient less than 0 K, cool discomfort was a possibility. Finger temperature and finger-forearm temperature gradient are very similar in their correlation to overall sensation. We also examine how overall sensation is affected by actively manipulating the hand's temperature.     

Toxicity of chlorine to juvenile spot, Leiostomus Xanthurus

The sensitivity of juvenile spot, Leiostomus xanthurus, to total residual chlorine (TRC) in flowing sea-water was investigated. Incipient LC₅₀ bioassays, histopathology, avoidance tests and the combined effect of thermal stress and TRC were used to assess sensitivity.

Estimated incipient LC₅₀ values were 0.12 mg 1⁻¹ TRC at 10°C and 0.06 mg 1⁻¹ TRC at 15°C. Histological examination of spot used in the incipient LC₅₀ bioassay at 15°C and sacrificed while alive indicated pseudobranch and gill damage occurred in individuals exposed to a measured TRC concentration of 1.57 mg 1⁻¹. Spot exposed to lower concentrations of TRC, 0.02 0.06 mg 1⁻¹ at 15°C and sacrificed alive showed no consistent tissue damage.

Spot demonstrated temperature dependent avoidance responses to TRC. At 10°C, a concentration of 0.18 mg 1⁻¹ was required for significant (X²; P < 0.05) avoidance; at 15 and 20°C, spot showed significant avoidance of TRC concentrations as low as 0.05 mg 1⁻¹.

Simultaneous exposure of spot to thermal stress (5, 10 or 13°C above the acclimation temperature of 15°C) at measured TRC concentrations of 0.05 0.07 and 0.34–0.52 mg 1⁻¹ demonstrated a significant, (Z²) with Yates correction, P < 0.05) increase in sensitivity to TRC with increased temperature and exposure times for some of the groups tested.     

Temperature influence on bacterial populations in three aquatic systems

Effects of temperature changes on bacterial populations in three aquatic systems were studied in the Thermal Effects Laboratory of the USAEC's Savannah River Laboratory. At monthly intervals for 12 months, total plate counts and diversity of heterotrophic, mesophilic bacteria were determined from a natural stream, two artificial streams, and two outdoor ponds. Water for artificial systems was drawn from the natural stream.Effects of changes in ambient temperature were analyzed in natural and artificial streams and in an unheated pond. A second pond was heated above natural stream temperature. Temperature elevation resulted in increased total plate counts in each system. Bacterial diversity increased in all systems during the initial 3–4°C increase in temperature. However, a reduction in diversity occurred when temperature was maintained 4–10°C above the initial ambient temperature. Changes were observed in both nutritional types and genera.     

The effects of power plant condenser cooling water entrainment on the amphipod. Gammarus sp.

The abundant Hudson River amphipod Gammarus sp. was examined for viability before and during entrainment in the Indian Point cooling water system. The mean per cent survivial of Gammarus sp. sampled during ΔT's of 7.1–8.3°C and ambient temperatures of 24.9–26.0°C was 98.5 and 97.4 per cent for the two intake stations and 90.1 and 96.8 per cent for the discharge canal stations D-1 and D-2 respectively. A statistically significant (α = 0.05) difference was detected between the survival of Gammarus sp. at the intake stations and discharge station D-1. located near the upper end of the discharge canal. Entrained Gammarus sp. experience increased initial and latent mortalities during periods of condenser chlorination. Comparison of the abundances of entrained Gammarus sp. during day and night sampling periods reveals a significantly higher occurrence during darkness. Temperature bioassays indicate that the thermal tolerance of Gammarus sp. is dependent on exposure time and ambient temperature. The temperature resulting in a 50 per cent mortality of Gammarus sp. for 30 min exposure times increased approximately 11 C as ambient temperatures increased from 2.5 to 25.8°C. Consequently, Gammarus sp. was capable of surviving ΔT's of greater magnitude as the ambient temperature to which they were acclimated decreased. Temperature bioassays indicated that Gammarus sp. should be able to tolerate all projected time-temperature exposure combinations encountered during entrainment through the cooling water system.     

Innovative thermal technique for enhancing the performance of prefabricated vertical drain during the preloading process

This paper examines the effect of raising the temperature of soft Bangkok clay, up to 90 °C, on the performance of the prefabricated vertical drain (PVD) during the preloading process. The effect of temperature on the engineering behavior of soft Bangkok clay was first investigated using a modified triaxial test apparatus and flexible wall permeameter which can handle temperatures up to 100 °C. The results of the triaxial tests on clay specimens demonstrate that raising the soil temperature increases its shear strength, under drained heating condition, as well as its hydraulic conductivity. In addition, large oedometer tests were performed to investigate the performance of PVD at elevated temperatures. The response of the soil sample with PVD for the thermal consolidation path which involved increasing the soil temperature at constant vertical effective stress condition and the thermo-mechanical path which involved increasing simultaneously both the soil temperature and the vertical effective stress were investigated. The consequent results indicated that the thermo-mechanical path shows promising results regarding the consolidation rate. For both reconstituted and undisturbed specimens, higher consolidation rate was observed for the soil specimen with PVD loaded under elevated temperature. This behavior can be attributed to the increase in the soil hydraulic conductivity as the soil temperature increases. Therefore, raising the soil temperature during the preloading period can enhance the performance of the PVD, particularly, by reducing the drainage retardation effects due to the smear zone around PVD.     

Pentachlorophenol adsorption and desorption characteristics of granular activated carbon-I. Isotherms

The adsorption/desorption of pentachlorophenol (PCP) with Calgon F300 granular activated carbon (GAC) was studied and modelled. A modified Radke-Prausnitz (1972) isotherm model, incorporating a temperature- and pH-dependent proportionality constant, was found to best describe the observed PCP adsorption and desorption. The modified isotherm is valid in the ranges 4 ≤ pH ≤ 11 and 10 ≤ T ≤ 60°C. The activation energy of PCP adsorption was calculated to be 5.2 kJ/mol. At 30°C, PCP adsorbed strongly, and the rate of subsequent desorption was very low. However, the amount of PCP desorbed could be increased significantly by increasing the temperature to 60°C.     

Effect of silica fume on cement hydration and temperature rise of concrete in tropical environment

Investigated herein is the effect of temperature on heat development in cement pastes and concretes with and without silica fume cured at relatively high temperatures often encountered in tropical environment. With an initial temperature of 30°C, adiabatic temperature rise of the concrete with 8% silica fume as cement replacement was similar to that of the control Portland cement concrete up to about 18 h. After 24 h, however, the temperature of the silica fume concrete was lower than that of the control concrete. Since the concrete with 8% silica fume had a higher 28-day compressive strength (72.5 MPa) than the control concrete without silica fume (59.2 MPa), the concrete with silica fume is likely to have a lower temperature rise as compared with the control concrete of equivalent 28-day strength by reducing cementitious materials content with the same water content. The extent of heat evolution in the silica fume pastes was generally greater at lower temperatures of 20-50°C, but less at 65°C than in the control paste. At the relatively high curing temperatures, the degree of cement hydration in the paste with silica fume was lower than that in the control cement paste at early ages. However, the pozzolanic reaction started even before 24 h after water was added.     

Gel immobilization improves survival of Escherichia coli under temperature stress in nutrient-poor natural water

Viable Escherichia coli cells were entrapped in agar gel layers to form artificial biofilms. Sessile-like bacteria and planktonic (suspended) counterparts were exposed for 28 d to natural (spring)water at two temperatures (4°C and 18°C). Culturabilities on non-selective and selective solid media were monitored over the exposure period, together with cell viability that was determined by using a fluorescent viability probe and confocal scanning laser microscopy analysis. The number of planktonic organisms recovered on non-selective medium decreased by 3 logarithmic units during exposure at 4°C and was reduced to an undetectable level at 18°C. Whatever the temperature of the spring water microcosm, however, the immobilized-cell population did not decrease by more than one log unit over the exposure period. Cell counts on coliform-selective, lactose–deoxycholate agar plates confirmed the enhanced resistance of gel-entrapped cells to environment stress as compared to planktonic organisms: at the two tested temperatures, sublethal injury of suspended E. coli reached more than 80% whereas it did not exceed 65% for immobilized cells. Viability studies indicated that planktonic cells rapidly died. These results show that the ability of microorganisms to colonize aquatic ecosystems in the fixed state (i.e. as biofilms) must be considered in studies evaluating cell survival in these environments.     

Aerobic treatment of piggery waste

The operating characteristics of laboratory waste treatment systems were studied during the aerobic degradation of pig excrement at different loading rates and temperatures. The treatment systems were of two types: one was operated with floc formation and gravity separation of liquid and suspended solid effluents; and a second was operated without floc formation or separation of the effluent into liquid and solid fractions.

With an operating temperature of 15°C the parameters most affected by loading rate were (1) the concentrations of suspended solids and chemical oxygen demand in the liquid effluent; (2) the pH value of the mixed liquor; (3) nitrification; (4) the BOD of the supernatant from the mixed liquor; and (5) output of suspended solids as a percentage of input.

The concentrations of suspended solids and chemical oxygen demand in the liquid effluents were little affected by loading rates in the range 0·05-0·15 g SS g MLSS⁻¹ d⁻¹ (0·02-0·06 g BOD g MLSS⁻¹ d⁻¹) but increased with increasing loading rate in the range 0·15-0·30 (0·06-0·12 BOD). At loading rates below about 0·17 g SS g MLSS⁻¹ d⁻¹ (0·07 g BOD g MLSS⁻¹ d⁻¹) the mixed liquors were acidic, with pH values down to 5·2, whereas at loading rates above about 0·80 (0·32 BOD) they were alkaline, with pH values up to 8·9. At intermediate loading rates the mixed liquor pH value was more variable though in general the higher the loading rate the higher also the pH value of the mixed liquor. Acidic conditions in the mixed liquors were attributed to the occurrence of nitrification, while in the absence of nitrification the mixed liquors remained alkaline. The concentration of BOD₅ in the supernatant from the mixed liquors increased with increasing loading rate from about 35 mg 1⁻¹ at a loading rate of 0·17 g SS g MLSS⁻¹ d⁻¹ (0·07 g BOD g MLSS⁻¹ d⁻¹) to about 250 mg 1⁻¹ at a loading rate of 1·30 (0·52 BOD). The output of suspended solids from the treatment systems represented about 70 per cent of input suspended solids at loading rates of about 0·15 g SS g MLSS⁻¹ d⁻¹ (0·06 g BOD g MLSS⁻¹ d⁻¹) and increased to about 100 per cent at loading rates of 0·80 (0·32 BOD). Output of chemical oxygen demand was about 60 per cent of input at the lower loading rates and 80–90 per cent at the higher ones.

Operation of treatment units at temperatures of 5 and 10°C instead of 15°C had little effect on the efficiency of degradation at loading rates in the range 0·085-0·20 g SS g MLSS⁻¹ d⁻¹ (0·034-0·08 g BOD g MLSS⁻¹ d⁻¹), but nitrification was prevented at 5°C. At loading rates of 0·77 (0·31 BOD) and 1·46 (0·58 BOD) operation at 25°C appeared to increase the amount of degradation as compared with that achieved at 15°C.

The practical implications of the results and possible future approaches to the aerobic treatment of farm wastes are discussed.     

Effects of temperature and pH on the growth of heterotrophic bacteria in waste stabilization ponds

This paper presents the effects of temperature and pH on the growth of heterotrophic bacteria in Chlorella vulgaris-heterotrophic bacteria culture. The growth of heterotrophic bacteria was studied at 10, 15, 20 and 30°C, and pH was controlled from 3.0 to 11.5 in a series of fed-batch chemostat reactors supplied with glucose as the sole source of carbon. Samples were analyzed for heterotrophic bacteria by tryptone glucose extract agar in triplicate. The agar pH of 7.0 was the best for enumeration of heterotrophic bacteria. The bacteria grown at pH near neutral were more sensitive to the variation of agar pH than those grown at very alkaline pH. No significant difference in the number of cells capable of forming colonies was noted for incubation temperature of 20 and 35°C, but the lag time for colony formation was longer at 20°C. Samples for enumeration of heterotrophic bacteria collected from algal-bacterial systems such as waste stabilization ponds are recommended to be incubated at 35°C for 72 h. Depending on the pH of the culture, about 86–98% of the cells capable of forming colonies will be visible to the naked eyes after incubation at 35°C for 72 h. At the steady state conditions, heterotrophic bacteria were not sensitive to temperature in the range of 10–20°C. However, at 30°C, a notable competition for glucose between Chlorella vulgaris and heterotrophic bacteria was observed. This competition was responsible for the low bacterial density near neutral pH. No evidence was found to support the view that the discharge of bactericidal substances from Chlorella vulgaris was responsible for reduction of heterotrophic bacteria at high pH.     

Energy-absorption abilities of CFRP cylinders during impact crushing

This paper describes the energy-absorption abilities of thin-walled circular cylinders made from carbon-fibre-reinforced plastic (CFRP) during crushing under impact loading. The tests are carried out with an impact testing machine, the crosshead mass of which is 21.5 kg, at a velocity of 8 m s ⁻¹ under the temperature range 20 to 130°C. The ply angles of the specimens are 15 and 75°, their dimensions are 1.2 mm in thickness, 30 mm in inner diameter and 100 mm in length. Load-time and displacement-time profiles are acquired precisely by using a newly designed load cell and an optical displacement transducer. The acquired force and displacement profiles are converted to the force and deformation relationship, which manifests the energy-absorption abilities. The specimens produce two different types of crushing mode and definite constant load levels which keep their energy-absorption ability high. The energy-absorption abilities and the crushing modes of the specimens change at temperatures above 60°C.     

Variation of fracture toughness of asphalt concrete under low temperatures

This study presents the results of experimental evaluation on fracture toughness of asphalt concrete at various low temperatures (from −5°C to −30°C in 5°C steps). An asphalt cement, penetration grade of 85/100 and two aggregates, a granite and a limestone, were used to prepare asphalt concrete beam specimens which were conditioned using two different procedures and tested under three-point bending setup. The first procedure dealt with evaluation of fracture toughness of the asphalt concrete at a control temperature, −5°C, following conditioning at the specified temperatures. The second procedure dealt with evaluation of fracture toughness at the temperatures at which the samples were conditioned. The results showed that fracture toughness (K_IC) for both aggregate mixtures in both procedures changed in a manner that it increased by lowering temperature from −5°C to −15°C, and then decreased thereunder. An improved mechanical adhesion due to the strengthened grip of asphalt matrix resulted from differential thermal contraction (DTC) is responsible for increased resistance to the applied loads. The reduction of fracture toughness below −15°C is explained as the effect of internal damage due to DTC that is a consequence of the large difference in coefficients of thermal contraction between aggregate and asphalt cement. Granite aggregate mixture showed a slightly better resistance to fracture throughout the temperatures. Relatively good linear relations between average values of σ_f and K_IC were found from the regression analysis. Increasing flexural strength resulted in an increased fracture toughness for all mixtures. K_IC of granite mix showed more critical to the change of σ_f.     

Enhanced uptake of phosphorus by activated sludge-effect of substrate addition

Studies were undertaken to examine the effect of substrate addition upon the release and subsequent uptake of phosphorous by a biological wastewater treatment laboratory scale system.A train of six reactors were fed at a rate of 16 ml min⁻¹ raw wastewater using a sludge recycle ratio of 0.75 (12 ml min⁻¹). The first two reactors were simply stirred (anoxic) without the addition of air and the remaining four were aerated with excess air.Various substrates were added to the first reactor (anoxic) at different concentrations. It was determined that all the short chain substrates tested enhanced the release of phosphorus in the anoxic stages and subsequently led to increased biological uptake (removal) of phosphorus. The substrates tested included sodium acetate, acetic acid, butyric acid, ethanol and methanol.It was determined that 30 mg l⁻¹ sodium acetate was the optimum dose for biological release and uptake of phosphorus and the addition of any greater concentration had marginal effect on the ultimate removal of phosphorus.The effect of these substrates showed some specificity regarding phosphorus release, with butyric acid causing the greatest release and sodium acetate the least. However as far as phosphorus uptake (removal) was concerned, this phenomenon of substrate-specificity was less significant. For all substrates, effluent phosphorus concentration was within ± 1 mg l⁻¹ with an approximate mean concentration of 1 mg l⁻¹ residual.Phosphorus released (approx. 14 mg l⁻¹) at higher temperature (29°C) was 75% greater than at the lower temperature (24°C). Similarly the final residual phosphorus at 29°C was 33% lower than at 24°C.     

Effects of elevated operating temperatures on methanol removal kinetics from synthetic kraft pulp mill condensate using a membrane bioreactor

The feasibility of biologically removing methanol from kraft pulp mill evaporator condensate was investigated, using a high temperature membrane bioreactor (MBR). Over the range of temperatures investigated (55–70°C), a mixed culture of methanol-utilizing microorganisms could be successfully developed, using synthetic condensate as a feedstock. A maximum specific methanol utilization coefficient of approximately 0.81 day⁻¹ occurred at an operating temperature of 60°C. Over 99% of the methanol was removed from the condensate at operating temperatures of 55 and 60°C. Above 60°C, the specific methanol utilization coefficient declined sharply, indicating that at high operating temperatures, the inactivating effect of temperature on the mixed culture of microorganisms must be considered. A relatively simple model was proposed and used to estimate the effect of high temperatures on methanol removal kinetics in an MBR over the range of temperatures investigated. The operating temperature also had a significant effect on the observed growth yield. At increasing operating temperatures, a larger fraction of the methanol consumed was converted to energy, reducing the observed growth yield.     

RESIDUE CHARACTERISTICS AND PORE DEVELOPMENT OF PETROCHEMICAL INDUSTRY SLUDGE PYROLYSIS

Petrochemical industry bio-sludge was pyrolyzed to investigate the composition and pore size distribution of pyrolytic residue. Results indicated that the carbon, nitrogen, and hydrogen concentrations could be reduced after an increase in pyrolytic temperature. The trace element analysis indicated that Al, Ca, Fe, Mg, K, Cu, Sr, and Sb concentrated during the pyrolytic process. When forty grams of pre-dried sludge were pyrolyzed at various pyrolytic temperatures, the transfers from the gas phase to liquid phase to residue were from 21.2 to 36.0%, from 49.0 to 70.0%, and from 8.3 to 16.5%. Results of the pore size distribution examination indicated that the mesopore had the greatest effect on the bio-sludge pyrolysis. The optimal pyrolytic temperatures and times were approximately 800°C for 30 min and 900°C for 10 min. The conceptual model can reasonably explain the pore structure development during the pyrolysis process.