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1.
In this paper, a novel process for organic acids and nutrient recovery from municipal sludge was introduced and evaluated based on laboratory-scale studies. An economical estimation for its practical application was also performed by mass balance in a full-scale plant (Q=158,000 m3 d(-1)). This novel process comprises an upflow sludge blanket-type high performance elutriated acid fermenter (5d of SRT) for organic acids recovery followed by an upflow-type crystallisation (3 h of HRT) reactor using waste lime for nutrient recovery. In the system, the fermenter is characterised by thermophilic (55 degrees C) and alkaline conditions (pH 9), contributing to higher hydrolysis/acidogenesis (0.18 g VFA(COD) g(-1) VSS(COD), 63.3% of VFA(COD)/COD produced, based on sludge characteristics of the rainy season) and pathogen-free stabilised sludge production. It also provides the optimal condition for the following crystallisation reactor. In the process, the waste lime, which is an industrial waste, can be used for pH control and cation (Ca and Mg) sources for crystallisation reaction. A cost estimation for full-scale application demonstrates that this process has economic benefits (about 67 dollars per m3 of wastewater except for the energy expense) even in the rainy season. 相似文献
2.
The study was designed to investigate the effects of temperature and phosphorus limitation on polyhydroxyalkanoate (PHA) production and storage by activated sludge biomass. The two-stage operation approach, i.e. a growth phase followed by a nutrient limitation phase, was applied to induce PHA accumulation. The pre-selected temperatures of 10, 20 and 30 degrees C were investigated under phosphorus limitation conditions using three four-litre fully aerobic SBR systems operated at an SRT of 10 days with cycle time and HRT of 6 and 10 hours. PHA production was greater in the 10 degrees C system than in the 20 degrees C and 30 degrees C systems but there was little difference between the two higher temperatures. The maximum PHA fractions of the sludge were 52, 45 and 47%TSS for the three temperatures from low to high, and the maximum PHA concentrations in the mixed liquors were 1,491, 1,294 and 1,260 mg/l, respectively. However, it was observed that very low values of PHA yield per unit COD consumed were obtained, i.e., 0.05, 0.03 and 0.04 mgPHA/mgCODu, for the 10, 20 and 30 degrees C reactors, respectively. This was because all three systems required several days to reach maximum PHA accumulation in their mixed liquor biomasses. It is probable the bacteria still had some stored poly-P in their cells upon initiation of the phosphorus limited influent, and PHA accumulation was delayed until the stored phosphorus was depleted. Also, PHA productivity was reduced by the large amounts of biomass lost from the systems because of sludge bulking. 相似文献
3.
This study focused on the treatment performance of membrane-coupled organic acid fermentor (MOF) with intermittent reciprocal air/ozone backwashing for the keeping of high permeation flux as well as for the effective recovery of dissolved organics from municipal sewage sludge. Intermittent reciprocal air/ozone backwashing was effective for membrane fouling reduction. When MOF was operated under the conditions of pH 5.5, hydraulic retention time (HRT) of 2 days and 20 days of solids retention time (SRT), most favourable fermentation efficiency was attained. Great inhibition for acid producing by intermittent reciprocal air/ozone backwashing was not observed during long-term operation. MOF with intermittent reciprocal air/ozone backwashing is believed to be an effective system for the recovery of organic matter from municipal sewage sludge and membrane fouling reduction. 相似文献
4.
In the present study, phosphorus removal was studied using as coagulant spent alum sludge from a water treatment plant of EYDAP (Athens Water Supply and Sewerage Company) and compared to alum (Al2(SO4)3.18H2O), iron chloride (FeCl3.7H2O), iron sulfate (Fe2(S04).10H2O) and calcium hydroxide (Ca(OH)2) at a constant pH (equal to 6).The comparison was based on their efficiency to remove phosphorus in synthetic wastewater consisting of 10 mg/L P as potassium dihydrogen phosphate and 50 mg/L N as ammonium chloride, The experiments were carried out using a jar-test apparatus and the measurements were performed according to the Standard Methods for the Examination of Water and Wastewater. Pure alum, iron chloride and iron sulfate were much more efficient in phosphorus removal than the spent alum sludge but in the case of calcium hydroxide, phosphorus removal was very low in pH = 6. Specifically, orthophosphate were totally removed by alum using 15 mg/L as Al, by alum sludge using 75 mg/L as Al and by FeCl3.7H2O or Fe2(SO4).10H2O using 30 mg/L of Fe while in the case of calcium hydroxide P removal was actually zero. pH measurements showed that the uptake of phosphates is associated to the release of OH ions in the solution and that the end of P uptake is accompanied by the stabilization of pH. Finally this spent alum sludge was tested on municipal wastewater and proved to be effective as apart from phosphorus it was shown to remove turbidity and COD. 相似文献
5.
Araujo JC Campos AC Correa MM Silva EC Matté MH Matté GR Von Sperling M Chernicharo CA 《Water science and technology》2011,64(7):1428-1434
A sustainable option for nitrogen removal is the anaerobic ammonium-oxidizing (anammox) process in which ammonium is oxidized to nitrogen gas with nitrite as electron acceptor. Application of this process, however, is limited by the availability of anammox biomass. In this study, two Brocadia-like anammox phylotypes were successfully enriched, detected and identified from an activated sludge taken from a domestic wastewater treatment plant (Minas Gerais, Brazil) employing a Sequencing Batch Reactor (SBR). The dominant phylotype was closely related to 'Candidatus Brocadia sinica', but one clone seemed to represent a novel species for which we propose the name 'Candidatus Brocadia brasiliensis'. Based on Fluorescence in situ hybridization (FISH) analysis, this enrichment led to a relative population size of 52.7% (±15.6) anammox bacteria after 6 months of cultivation. The cultivation process can be divided into three phases: phase 1 (approximately 25 days) was characterized by heterotrophic denitrification metabolism, phase 2 was the propagation phase and phase 3 (from the 87th day onwards), in which significant anammox activity was detected. A long-term performance of the SBR showed a near perfect removal of nitrite based on the influent NO(2)(-)-N concentration of 61-95 mg L(-1). The average ammonia removal efficiency was 90% with the influent NH(4)(+)-N concentration of 55-82 mg L(-1). Therefore, anammox cultivation and enrichment from activated sludge was possible under a controlled environment within 3 months. 相似文献
6.
Membrane-coupled anaerobic digestion utilizes a concept of simultaneous sludge digestion and thickening. Membranes may successfully be applied to eliminate the need for thickening polymers and avoid their likely inhibitory effect on anaerobic biomass. A 550 L completely mixed anaerobic digester was operated under mesophilic conditions (35 degrees C). Two ultrafiltration membrane systems were evaluated for their potential in membrane-coupled anaerobic digestion: vibrating and cross flow. A volatile solids reduction of 590% was achieved at an average mixed liquor suspended solids concentration of 1.8%. The substrate utilization rate was 1.3 d(-1). The vibrating membrane operated at a flux of 1.6-2.0 m3/m2-d and the tubular membrane fluxes in the range 3.4-3.6 m3/m2-d. 相似文献
7.
C Niewersch C N Koh T Wintgens T Melin C Schaum P Cornel 《Water science and technology》2008,57(5):707-714
Due to the depletion of mineral phosphorus resources there is an increasing demand for efficient phosphorus recovery technologies. In this study the potential of nanofiltration to recover phosphorus from pre-treated sewage sludge is investigated. The efficiency of three commercial nanofiltration membranes (Desal 5DK, NP030; MPF34) was tested using model solutions. Desal 5DK showed the best selectivity for phosphorus. A pH of lower than 1.5 was found to be most suitable. Desal 5DK was used on four different sewage sludge ash eluates and on one sewage sludge. In these experiments it was shown that a separation of phosphorus from undesired components such as heavy metals was possible with significant variations in the efficiency for the different ash and sludge types. Additionally the achievable product recovery was investigated with model solutions. A product recovery of 57.1% was attained for pH 1 and 41.4% for pH 1.5. 相似文献
8.
EPS are supposed to be among the causes of membrane fouling in membrane bioreactors (MBR). In this work they are measured as total proteins and total polysaccharides. Theoretical and empirical considerations of biomass membrane filtration lead to the conclusion that EPS in the water phase is decisive for the filterability of activated sludge. In this study therefore different ways of separating the water phase from the biomass are investigated, where a simple filtration over a paper filter turned out to be sufficient. Subsequently, a simple batch test set up was used to investigate the influence of substrate conditions on the amount of EPS in the water phase. Dilution of the biomass does not result in changes. Dilution together with substrate addition leads to an increase both in proteins and polysaccharides. Replacement of the water phase leads to no significant changes in protein concentration, but polysaccharide concentration may vary considerably. This phenomenon is more pronounced after replacement of the water phase and substrate addition. 相似文献
9.
Polyhydroxyalkanoates (PHAs) accumulating bacteria were isolated from activated sludge samples collected from municipal wastewater treatment plants in Quebec. Twelve bacterial strains were screened for PHA production with acetate as sole carbon source. PHA granules exhibited a strong orange fluorescence when stained with Nile blue A observed under microscope (X100x). PHA was also analyzed by Gas Chromatography Linked to Mass Spectroscopy (GCMS) to further confirm the presence and the concentration of PHA. To compare the abilities of these PHA accumulating bacterial strains, synthetic media with acetate as carbon source was prepared to accumulate PHA in 500 mL Erlenmeyer flask containing 150 of the medium. These flasks were then inoculated with the isolated bacterial strains, incubated at 25 degrees C for 48 hours in a rotary shaker at 220 rpm. The results showed that the bacterial strains isolated from sludge possess different abilities for accumulating PHA. The maximum PHA content of 27.50% was obtained by strain PHA-SB3. The PHB/PHV ratio of the copolymer produced in the study changed in accordance with operating time and strains. 相似文献
10.
城市污水处理厂剩余污泥热值估算方法研究 总被引:1,自引:0,他引:1
污水处理厂剩余污泥所具有的热值是衡量其能量利用价值的重要指标。目前的热值分析方法检测步骤繁琐、成本高,在污水处理厂的实际应用中有一定的困难。以北京市5座污水处理厂的剩余污泥为研究对象,通过测量污泥样品的挥发性固体(VS)与总固体(TS)含量和污泥的热值,发现污泥的VS/TS与污泥热值具有良好的线性关系,由此确定出估算污泥热值的计算公式。并采用多座污水处理厂的污泥数据对公式的适用性进行验证。对比分析表明,该公式能较准确地估算污泥热值,且其操作和所需仪器设备更为简单,能够根据污水处理厂日常对VS和TS的分析值快速估算污泥的热值。 相似文献
11.
城市污水污泥中邻苯二甲酸酯的研究 总被引:3,自引:2,他引:3
应用GC/MS对北京城市污泥中的6种邻苯二甲酸酯类环境激素进行了研究。结果表 明,北京城市污泥中邻苯二甲酸酯的总含量(∑PAEs)为20.798-58.245 mg/kg干污泥,其中 DEHP含量最高,约占∑PAEs的90%以上,其余邻苯二甲酸酯类化合物含量较低。影响城市污泥 中邻苯二甲酸酯含量的可能因素包括邻苯二甲酸酯的理化性质、生物降解性能、污水及污泥处理工 艺及污水中邻苯二甲酸酯的来源及含量等。今后应加强对邻苯二甲酸酯迁移转化规律和处理工艺 等方面的研究。 相似文献
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市政污泥与生活垃圾协同焚烧不仅能够实现污泥减量化、资源化,而且能达成设备共享,是一种具有综合效益的污泥处置方式.针对三类常见的协同处置模式进行对比分析,研究了污泥掺烧比例对焚烧厂污泥综合处置成本的影响. 相似文献
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This paper deals with the performances obtained in full scale anaerobic digesters co-digesting waste activated sludge from biological nutrients removal wastewater treatment plants, together with different types of organic wastes (solid and liquid). Results showed that the biogas production can be increased from 4000 to some 18,000 m3 per month when treating some 3-5 tons per day of organic municipal solid waste together with waste activated sludge. On the other hand, the specific biogas production was improved, passing from 0.3 to 0.5 m3 per kgVS fed the reactor, when treating liquid effluents from cheese factories. The addition of the co-substrates gave minimal increases in the organic loading rate while the hydraulic retention time remained constant. Further, the potentiality of the struvite crystallisation process for treating anaerobic supernatant rich in nitrogen and phosphorus was studied: 80% removal of phosphorus was observed in all the tested conditions. In conclusion, a possible layout is proposed for designing or upgrading wastewater treatment plants for biological nutrients removal process. 相似文献
16.
J A Cacho Rivero N Madhavan M T Suidan P Ginestet J M Audic 《Water science and technology》2005,52(1-2):237-244
The effect of oxidative and thermo-oxidative co-treatment of excess municipal sludge was investigated. A mixture of primary and waste activated sludge was anaerobically treated using two different configurations: i) two stages and ii) a single stage with recycling. Oxidative or thermo-oxidative co-treatment placed in between the reactor or in the recycle line was studied. A two-stage configuration with no co-treatment served as a control and resulted in 50.1% overall solids removal. Compared to the control, an increase in solids removal of 10.8 and 2.7% was observed when oxidative co-treatment was placed between reactors and in the recycle line respectively. When thermo-oxidative co-treatment was placed between the two stages or in the recycle line an increase in solids removal of 25.1 and 26.9% respectively was observed. The performances of the different configurations were also evaluated with parameters such as COD, TKN, ammonia, and fecal coliform concentration. 相似文献
17.
城市污水脱氮除磷SBR在线控制系统研究 总被引:10,自引:0,他引:10
SBR采用进水—厌氧—好氧—缺氧—好氧—沉淀—出水的运行方式处理城市污水。反应器装备有DO、ORP和pH等在线检测传感器。DO、ORP和pH变化的一些特征点可以用来判断和控制SBR中污水脱氮除磷过程的各个步骤。这包括:厌氧时,ORP和pH的转折点对应磷的释放;一次好氧时,DO、ORP的氨肘和pH的氨谷对应硝化结束;缺氧时,ORP的硝酸盐膝和pH的硝酸盐峰对应反硝化结束;二次好氧时,DO、ORP碳肘对应剩余碳的氧化结束,pH的转折点对应聚磷结束。控制系统能进行全自动运行来完成污水的脱氮除磷。 相似文献
18.
S Nielsen 《Water science and technology》2005,51(9):109-117
Linear alkylbenzene sulphonates (LAS) and nonylphenolethoxylates (NPE) may be detrimental to the environment if spread in inappropriately large concentrations. Mineralisation of LAS and NPE in mesophilic digested sludge was observed during a 9-month monitoring programme where three separate treatment methods were investigated. Sludge was treated in a sludge reed bed under aerobic conditions, by storage in a container under anaerobic conditions, and by storage in a sludge pile turned over mechanically at intervals to improve the oxygen influx. Treatment in a sludge reed bed was shown to be effective. Mineralisation of 98% of LAS and 93% of NPE was observed. Only limited mineralisation occurred on the surface of the sludge stored in a container. A reduction of LAS and NPE of 90% and 43%, respectively, was observed in the sludge which was stored in a pile and frequently turned. 相似文献
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对城市污泥好氧消化过程中DEHP和DMP的降解进行了研究,并重点研究了难降解有机物DEHP在不同浓度下对易降解有机物DMP的抑制效果.研究表明,好氧消化污泥对DEHP和DMP有较强的降解能力,且对DMP的降解能力明显强于DEHP,好氧消化污泥在500 mg/L难降解有机物DEHP存在的情况下,对50 mg/L有机物DMP的去除率仍高达99.8%;当DEHP的初始浓度在200 mg/L时,对DMP的降解速率影响较大,而在50 mg/L和500 mg/L时,影响较小;但历经10 d以后,不同初始浓度的DEHP对DMP的好氧降解速率几乎没有影响. 相似文献