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Beril Akin 《洁净——土壤、空气、水》2008,36(4):360-365
The production of excess sludge is one of the most serious challenges in biological wastewater treatment. In the present work, disintegration is added as a new additional unit operation in a wastewater treatment plant, and the main objective is to reduce the amount of excess sludge. The use of high power ultrasound can effectively disintegrate the bacterial cells, and thereby, enhance the subsequent biodegradation during digestion. In the study, attempts are made to determine the disintegration capacity of waste activated sludge that has different total solids (TS) concentrations with low ultrasound frequency (20 kHz) and a fixed amplitude value (50%). The results show that in terms of soluble chemical oxygen demand (SCOD) release, sludge disintegration was primarily governed by ultrasonic density (W mL–1), whereas specific energy input appears to be more critical for protein release. A SCOD release of about 329 mg SCOD gTS–1 was obtained at a TS content of 2% and specific energy input of 5 kWs gTS–1. The SCOD release decreased to 248.5 and 124.2 mgSCOD gTS–1 at TS contents of 4 and 6%, respectively. The highest protein release of 80.7 mg gTS–1 was obtained at a TS content of 2% and a specific energy input of 10 kWs g–1. The sludge disintegration efficiency declined significantly at higher TS content. 相似文献
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Sludge pretreatment prior to anaerobic digestion has been found to reduce sludge production in wastewater treatment. Sludge disintegration using physical, chemical, biological, or mechanical methods can increase biogas production and reduce sludge quantities. Ultrasonication is one of the most effective means of mechanical disintegration. This study aims to investigate ultrasonication as a means for solubilizing waste activated sludge (WAS) to enhance its digestability. Sonication was applied by the use of two different probes providing different powers and energies into the sludge after which the soluble chemical oxygen demand (sCOD) increases were measured. The samples were then digested anaerobically in 250 mL serum bottles for about 50 days. Along with the biogas measurements, the rate of methane production is calculated to be able to quantify the effect of pretreatment and compare the results between different applications. The results showed that with the increase of sonication power and sonication time, sCOD increased. An introduction of higher sonication energy made the sCOD rise sharply, however, this increase was not indefinite; it became gradually lower with the further increase of energy. The results indicated that specific methane production, specific methane yield, and the first order methane generation rate increased with increasing energy input. 相似文献
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A method is described for determining the course of inhibition curves substantiating the influence of some inorganic (Cr (VI)) and organic substances (phenol, synthetic tanning agents) on respiratory activity of heterogeneous biomass (activated sludge). Presented results prove that calculated inhibition curves have the course of a normal distribution function. 相似文献
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Tzu‐Yi Pai Terng‐Jou Wan Yung‐Pin Tsai Chwen‐Jeng Tzeng Hsiao‐Hsing Chu Yao‐Sheng Tsai Ching‐Yuan Lin 《洁净——土壤、空气、水》2010,38(2):167-172
In this study, the effect of sludge retention time on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in an anaerobic/oxic (AO) process, was explored. The results indicated that the growth rate constants of AOB were 0.97, 0.88, and 0.79 d–1, respectively, meanwhile, those of NOB were 1.22, 1.03, and 0.93 d–1, respectively, when the sludge retention time (SRT) was 15 days, 10 days and 5 days. The relation between the growth rate constant and the SRT could be best described using a simple exponential curve and a second type hyperbolic curve. The lysis rate constants for AOB and NOB were 0.13 and 0.18 d–1, respectively. The yield coefficients values of AOB and NOB were 0.22 and 0.21, respectively. The percentage of AOB to mixed liquid suspended solids (MLSS) was 0.64%, 0.53%, and 0.35%, respectively. Meanwhile, the percentage of NOB was 2.24%, 1.87%, and 1.11%, respectively, at SRT values of 15 days, 10 days and 5 days. When the SRT value decreased, the AOB and NOB biomass levels decreased by 12.75 and 47.01 mg L–1, respectively. Meanwhile the removal efficiency of NH4+‐N decreased from 90 to 26%, while the removal efficiency of total nitrogen (TN) decreased from 14 to 8%. 相似文献
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Norbert Schwarzenbeck Ron Erley Belinda S. Mc Swain Peter A. Wilderer Robert L. Irvine 《洁净——土壤、空气、水》2004,32(1):16-24
Aerobic granular sludge was successfully cultivated in a sequencing batch reactor (SBR) treating wastewater from the malting process with a high content of particulate organic matter. At an organic loading rate of 3.2 kg/(m3 d) CODtotal and an influent particle concentration of 0.95 g/L MLSS an average removal of 50% in CODtotal and 80% in CODdissolved could be achieved. A comparison of granular and flocculent sludge grown under the same operating conditions showed no significant difference in removal efficiency although granules exhibited a higher metabolic activity in terms of specific oxygen uptake rate (rO2, X). Two distinct mechanisms of particle removal were observed for granular sludge: during initial granule formation, particles were incorporated into the biofilm matrix. For mature granules, a high level of protozoa growth on the granule surface accounted for the ability to remove particulate COD. Combined evaluation of the development in MLSS content and sludge bed settling rate (i.e., mean derivative of the normalized sludge volume) was found to be an adequate method for monitoring the characteristic settling properties of a granulizing sludge bed. By means of this method, a distinct substrate gradient out of several operating conditions was concluded to have the biggest impact on the formation of aerobic granular sludge. 相似文献
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Heike Sütterlin Rainer Trittler Sebastian Bojanowski Ernst A. Stadlbauer Klaus Kümmerer 《洁净——土壤、空气、水》2007,35(1):81-87
Thermocatalytic low temperature conversion (LTC) is a new method for the disposal of sewage sludge. Using this method, sludge is converted into a residual solid (coal) along with reaction water, oil, and non‐condensable gases. The oil can be used as an energy source and the coal as a substitute for charcoal. To this end, it is important to determine whether there are any easily available contaminants present in the coal generated by the process. Contaminants that can be strongly sorbed by sewage sludge solids are, e. g., pharmaceuticals and disinfectants. As an example the fate of the persistent and strong adsorbing disinfectant benzalkonium chloride (BAC) has been investigated within the LTC process. The sewage sludge was spiked with BAC and then subjected to the LTC process. The resulting coal was extracted and analyzed using LC‐LC/ESI‐MS/MS (ion trap). BAC could not be detected in the LTC coal, although it could be extracted from the spiked sludge before the LTC treatment. It can thus be concluded that the investigated compound is not easily available in the coal, and hence that its use does not present a risk. 相似文献
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H. Jobst 《洁净——土壤、空气、水》1995,23(1):20-25
Chlorophenols and Nonylphenols in Sewage Sludges. Part I: Occurence in Sewage Sludges of Western German Treatment Plants from 1987 to 1989 Sewage sludges originating from all western German states from 1987 till 1989 have been analyzed for two groups of organic pollutants, which are not specified in the German sewage sludge regulations (Klärschlammverordnung) from 1992: the isomeric 4-nonylphenols and the chlorophenols. The applied analytical methods are presented, as well as the analytical results. In almost all 149 analyzed samples nonylphenols could be found, at an average of 128.2 mg/kg dry matter. In the case of chlorophenols, pentachlorophenol was the most pronounced in respect to amount and to frequency of positive results: i.e. in 85 samples investigated, the mean value was 59.5 μg/kg. Results are reported in percentils. The data correspond to sewage sludges from the past and will be used as a guideline in evaluating all following studies of sludges. Investigations will be continued. 相似文献
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55,000 tons of sewage sludge are dumped each winter in the Hurst Deep, 22,500 tons a year in the Needles Spoil Ground. Investigation of the behaviour of the sludge after dumping and of the bottom fauna shows no obvious signs of deterioration and conditions may not have changed appreciably since surveys made 92 years ago. 相似文献
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Comparative Assessment of Sludge Pre‐Treatment Techniques to Enhance Sludge Dewaterability and Biogas Production 
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下载免费PDF全文 Didem Okutman Tas Cigdem Yangin‐Gomec Tugba Olmez‐Hanci Osman A. Arikan Deniz I. Cifci Elif B. Gencsoy Alpaslan Ekdal Emine Ubay‐Cokgor 《洁净——土壤、空气、水》2018,46(1)
Effectiveness of ultrasonication, microwave technologies, and enzyme addition prior to anaerobic digestion is investigated using sludge samples taken from the secondary settling tank of a domestic wastewater treatment plant to improve methane production, enhance dewaterability characteristics of the sludge, and to reduce excess sludge. Microwave pre‐treatment (1500 W, 10 min at 175 °C) results in better extra digester performance (compared to the control reactor) in terms of methane production (25 m3 ton?1 suspended solids (SS)) than ultrasound (no improvement) and enzyme pre‐treatment (11 m3 ton?1 SS). While methane production is not improved as a result of ultrasonication pre‐treatment (15 000 kJ kg?1 SS), a noticeable increase (19%) is observed in the case of microwave pre‐treatment. Higher compactibility values are obtained after ultrasonication and microwave application compared to the control (i.e., from 7.1 to 8.7 and 9.2%, respectively) before anaerobic digestion. Although ultrasonication and microwave application decrease the dewaterability of the raw sludge (capillary suction time (CST) from 827 to 1364 and 2290 s, respectively), similar dewaterability results are obtained at the end of the anaerobic digestion process for all pre‐treated sludge samples. An economic assessment of this study shows that pre‐treatment with microwave results in more than 10‐fold less net cost compared to the enzyme application. 相似文献
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Dewatering Behaviour of Sludge in the Presence of Polyelectrolytes Interactions of sludge particles with well defined synthetic polyelectrolytes of different charge, molecular mass, and molecular geometry were investigated by means of zeta- and streaming potential measurements and polyelectrolyte titrations. Different mechanisms of flocculation were discussed with regard to the dewatering behaviour of the sludge. In dependence on the flocculation procedure (cationic monoflocculation, anionic-cationic, and cationicanionic dual flocculation) as well as on the chain length and branching of the polyelectrolytes used, different mechanisms of sludge dewatering were discussed: Polyanions are not adsorbed on the sludge particles and lead to a decline of the dewatering results. Linear short chain polycations result in a flocculation after surface charge neutralization of the particles according to a patch mechanism. Long chain linear polycations cause a bridging of the particles leading to a flocculation without charge neutralization of the aggregates formed. With branched polycations, a flocculation according to a patch mechanism is observed. These polycations form sludge particle aggregates which are surface charge neutralized at the flocculation point. In anionic-cationic dual flocculations using long chain polycations, an inclusion flocculation due to polyanion-polycation complex formation is the predominating mechanism. The cationic-anionic dual flocculation with complete covering of the particles with polycations in the first step can be discussed by a patch mechanism quite similar to an anionic monoflocculation of cationic particles. By knowing the mechanism of interaction for a given flocculation agent, an optimal sludge dewatering procedure can be predicted. 相似文献
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Xuefei Zhou Yalei Zhang Lu Shi Jiabin Chen Zhimin Qiang Tian C. Zhang 《洁净——土壤、空气、水》2013,41(8):820-827
Laboratory‐scale batch experiments were conducted to investigate the adsorption behavior of eight fluoroquinolones (FQs) on aerobic, anoxic, and anaerobic sludge, under different adsorpiton time, pH, and temperature conditions. Results indicated that adsorption of FQs onto all sludge was a physical sorption process. The relationship of the partitioning coefficient (Kd) and the octanol/water partition coefficient (Kow) for each FQ was established. The adsorbed fraction of FQs on sludge could then be predicted with the Kd. It was calculated that about 50–72% of the FQs were adsorbed on the sludge. Therefore, the adsorption effect must be considered when studying the fate and occurrence of FQs in wastewater treatment systems. 相似文献
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Kathryn S. Makeig 《Ground water》1982,20(4):420-429
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The mixtures of dried sewage sludge (DSS) and sewage sludge ash were studied for removal of acid red 119 (AR119) dye as a new, more environmental friendly, and low cost adsorbent. For this purpose, response surface methodology was applied to optimize the dye removal efficiency and turbidity of treated dye solutions as two individual responses. Results revealed that an optimum condition under specified constraints (dye removal efficiency >95% and turbidity <50 NTU) was obtained at a contact time of 60 min, 40 wt% DSS in the mixture, an initial pH of 6, and an initial dye concentration of 200 mg dye/L in distilled water. Under the optimal condition, dye removal efficiency of 94.98% and effluent turbidity of 24.9 NTU was observed. In further studies, at optimum condition, the effect of some additives on adsorption process and desorption/reusability of adsorbent was investigated. It was observed that removal efficiency was significantly decreased to 83.76% when a simulated dye wastewater (containing the selected dye, acetic acid, and Glauber's salt dissolved in tap water) was used. Desorption studies revealed that AR119 dye could be well removed from dye‐loaded adsorbent by 0.3 M NaOH solution. 相似文献
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J. Chudoba 《洁净——土壤、空气、水》1987,15(5):445-457
Basic principles determining and substantiating the contents of organics in secondary effluents were formulated and discussed. It has been shown that the activated sludge process, if optimally designed and operated, can produce secondary effluents with soluble carbonaceous BOD5 values below 5 mg/1 and suspended solids concentrations approaching 10 mg/1. While the total values of BOD5 are significantly influenced by SS concentrations, the total values of COD are influenced mostly by soluble refractory organics present in raw wastewaters and formed in the process as microbial waste products. 相似文献