Odorants and malodors associated with land application of biosolids stabilized with lime and coal fly ash

Malodor emissions limit public acceptance of using municipal biosolids as natural organic resources in agricultural production. We aimed to identify major odorants and to evaluate odor concentrations associated with land application of anaerobically digested sewage sludges (Class B) and their alkaline (lime and coal fly ash)-stabilized products (Class A). These two types of biosolids were applied at 12.6 tonnes ha(-1) (dry weight) to microplots of very fine clayey Vertisol in the Jezreel Valley, northern Israel. The volatile organic compounds (VOCs) emitted from the biosolids before and during alkaline stabilization and after incorporation into the soil were analyzed by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry. Odor concentrations at the plots were evaluated on site with a Nasal Ranger field olfactometer that sniffed over a defined land surface area through a static chamber. The odors emitted by anaerobically digested sewage sludges from three activated sludge water treatment plants had one characteristic chemical fingerprint. Alkaline stabilization emitted substantial odors associated with high concentrations of ammonia and release of nitrogen-containing VOCs and did not effectively reduce the potential odor annoyance. Odorous VOCs could be generated within the soil after biosolids incorporation, presumably because of anaerobic conditions within soil-biosolids aggregates. We propose that dimethyl disulfide and dimethyl trisulfide, which seem to be most related to the odor concentrations of biosolids-treated soil, be used as potential chemical markers for the odor annoyance associated with incorporation of anaerobically digested sewage sludges.     

Leaching characteristics of heavy metals from sewage sludge by Acidithiobacillus thiooxidans MET

An acidophilic, sulfur-oxidizing Acidithiobacillus thiooxidans MET bacterium was isolated from anaerobically digested, dewatered sewage sludge. This bacterium showed sulfur-oxidizing ability at both acidic and neutral conditions, and allowed metal leaching even at a high (130 g L(-1)) sludge solids concentration. We found that low metal leaching efficiency at high solids concentration was mainly due to an increase in buffering capacity resulting in retardation of pH reduction. Therefore, metal leaching was mainly influenced not by sludge solids concentration, but by the pH (or sulfate concentration per unit sludge mass) of the sludge solutions. The relationship between the pH of the sludge solution and the efficiency of metal leaching was obtained by quantitatively investigating the effect of pH reduction or the amount of sulfate produced per unit sludge mass on leaching of each metal. Furthermore, the relationship between total metal content in the sludge and metal leached to the solution was obtained for each metal. Such a relationship allowed estimation of leachable metal at various amounts of total metal content in sludge.     

Aerobic treatment of palm oil mill effluent

In this study treatment of palm oil mill effluent (POME) was investigated using aerobic oxidation based on an activated sludge process. The effects of sludge volume index, scum index and mixed liquor suspended solids during the acclimatizing phase and biomass build-up phase were investigated in order to ascertain the reactor stability. The efficiency of the activated sludge process was evaluated by treating anaerobically digested and diluted raw POME obtained from Golden Hope Plantations, Malaysia. The treatment of POME was carried out at a fixed biomass concentration of 3900+/-200mg/L, whereas the corresponding sludge volume index was found to be around 105+/-5mL/g. The initial studies on the efficiency of the activated sludge reactor were carried out using diluted raw POME for varying the hydraulic retention time, viz: 18, 24, 30 and 36h and influent COD concentration, viz: 1000, 2000, 3000, 4000 and 5000mg/L, respectively. The results showed that at the end of 36h of hydraulic retention time for the above said influent COD, the COD removal efficiencies were found to be 83%, 72%, 64%, 54% and 42% whereas at 24h hydraulic retention time they were 57%, 45%, 38%, 30% and 27%, respectively. The effectiveness of aerobic oxidation was also compared between anaerobically digested and diluted raw POME having corresponding CODs of 3908 and 3925mg/L, for varying hydraulic retention time, viz: 18, 24, 30, 36, 42, 48, 54 and 60h. The dissolved oxygen concentration and pH in the activated sludge reactor were found to be 1.8-2.2mg/L and 7-8.5, respectively. The scum index was found to rise from 0.5% to 1.9% during the acclimatizing phase and biomass build-up phase.     

西安市生活污水厂污泥中重金属特性及再利用风险评价

通过评价西安市污水厂污泥理化性质、重金属含量和潜在生态风险,探究污泥再利用的可行性.分析了西安市7个具有代表性的生活污水处理厂污泥的基本理化性质和6种重金属(Cr、Cu、Ni、Pb、Cd和Zn)在不同时期的含量变化,并对污泥再利用做了可行性评价和潜在风险评价.结果 表明,各污水厂污泥除XA3污水厂Cd未达标外,其余污水...     

上海市污泥集装化运输可行性研究

随着上海市生活垃圾集装化运输系统的逐步完善和发展,上海市污泥的集装化运输逐渐被提上日程。本文通过对上海市中心城区的10座城市污水处理厂的污泥产量、污泥含水率、污泥运输道路和装卸环境等进行系统调研,综合分析和研究了上海市各污水处理厂污泥集装化运输的可行性,并进一步研究了污泥性质对集装化运输的影响。结果表明,上海市中心城区仅白龙港污水处理厂含水率约为60%的深度脱水污泥符合污泥集装化运输的要求;深度脱水污泥性质较为稳定,对各种钢材料的腐蚀性为0.00016~0.00125 mm/a,对集装化运输影响较小,但污泥释放的氨气浓度高达173.66 mg/m3,影响集装化运输,需采取水雾喷洒等措施进行控制。     

Effect of dissolved organic matter from sludge and sludge compost on soil copper sorption

Interaction of Cu with dissolved organic matter (DOM) is an important physicochemical process affecting Cu mobility in soils. The aim of this study was to investigate the effects of DOM from anaerobically digested dewatered sludge and sludge compost on the sorption of Cu on an acidic sandy loam and a calcareous clay loam. In the presence of DOM, Cu sorption capacity decreased markedly for both soils, especially for the calcareous soil. The Cu sorption isotherms could be well described by the Freundlich equation (r2 = 0.99), and the binding intensity parameter of soils in the presence of sludge DOM was lower than compost DOM. An increase in DOM concentration significantly reduced the sorption of Cu by both soils. Within the Cu and DOM concentration range studied, the decrease in Cu sorption caused by sludge DOM was consistently greater than that of compost DOM. This might be attributed to the greater amount of hydrophobic fraction of DOM in the compost. Moreover, the reduction of Cu sorption caused by DOM was more obvious in the soil with higher pH. In addition, the sorption of Cu increased with an increase in pH for both soils without the addition of DOM, while Cu sorption in the presence of DOM was unexpectedly decreased with an increase in pH at a pH >6.8. This implied that DOM produced by sludge or other C-enriched organic wastes heavily applied on calcareous soils might facilitate the leaching loss of Cu because of the formation of soluble DOM-metal complexes.     

Phosphorus transfer in runoff following application of fertilizer, manure, and sewage sludge

Phosphorus (P) transfer in surface runoff from field plots receiving either no P, triplesuperphoshate (TSP), liquid cattle manure (LCS), liquid anaerobically digested sludge (LDS), or dewatered sludge cake (DSC) was compared over a 2-yr period. Dissolved inorganic P concentrations in runoff increased from 0.1 to 0.2 mg L(-1) on control and sludge-treated plots to 3.8 and 6.5 mg L(-1) following application of LCS and TSP, respectively, to a cereal crop in spring. When incorporated into the soil in autumn, runoff dissolved P concentrations were typically < 0.5 mg L(-1) across all plots, and particulate P remained the dominant P form. When surface-applied in autumn to a consolidated seedbed, direct loss of LCS and LDS increased both runoff volume and P transfers, but release of dissolved P occurred only from LCS. The largest P concentrations (>70 mg L(-1)) were recorded following TSP application without any increase in runoff volume, while application of bulky DSC significantly reduced total P transfers by 70% compared with the control due to a reduced runoff volume. Treatment effects in each monitoring period were most pronounced in the first runoff event. Differences in the release of P from the different P sources were related to the amounts of P extracted by either water or sodium bicarbonate in the order TSP > LCS > LDS > DSC. The results suggest there is a lower risk of P transfer in land runoff following application of sludge compared with other agricultural P amendments at similar P rates.     

Evaluation of biogas production from seaweed in batch tests and in UASB reactors combined with the removal of heavy metals

Seaweed can be anaerobically digested for the production of energy-rich methane. However, the use of seaweed digestate as a fertilizer may be restricted because of the high heavy metal content especially cadmium. Reducing the concentration of heavy metals in the digestate will enable its use as a fertilizer. In this laboratory-scale study, the potential of seaweed and its leachate in the production of methane were evaluated in batch tests. The effect of removing the heavy metals from seaweed leachate was evaluated in both batch test and treatment in an upflow anaerobic sludge blanket (UASB) reactor. The heavy metals were removed from seaweed leachate using an imminodiacetic acid (IDA) polyacrylamide cryogel carrier. The methane yield obtained in the anaerobic digestion of seaweed was 0.12 N l CH₄/g VS_added. The same methane yield was obtained when the seaweed leachate was used for methane production. The IDA-cryogel carrier was efficient in removing Cd²⁺, Cu²⁺, Ni²⁺ and Zn²⁺ ions from seaweed leachate. The removal of heavy metals in the seaweed leachate led to a decrease in the methane yield. The maximum sustainable organic loading rate (OLR) attained in the UASB reactor was 20.6 g tCOD/l/day corresponding to a hydraulic retention time (HRT) of 12 h and with a total COD removal efficiency of about 81%. Hydrolysis and treatment with IDA cryogel reduced the heavy metals content in the seaweed leachate before methane production. This study also demonstrated the suitability of the treatment of seaweed leachate in a UASB reactor.     

Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge

A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed.     

法国某生活污水厂污泥好氧消化工艺运行研究

为了提高出水质量,法国小镇Cagnes—sur—Mer的生活污水处理厂从2008年初开始实施高有机负荷的运行,但同时这也提高了出泥产量。由于污泥的处理费用及搬运污泥的交通费用很高,水厂对污泥进行了污泥好氧稳定工艺,工艺使用纯氧机（VSA装置）就地利用空气制氧。工艺投入运行后,每日对好氧消化池的入泥和出泥进行采样和检测（MLSS、MLVSS、pH、COD、DRYNESS etc）以建立完整的运行数据。污泥经好氧消化作用后其有机物含量减少60％以上,每月减少40吨的出泥。同时,消化池的使用还使水厂周日也能对曝气池中的污泥进行抽取,缓解了以往由于周日停止排泥而导致周一曝气池中污泥浓度过大的问题。从而达到优化出水水质的目的。消化池中的温度维持在40℃左右,因为反应为放热反应,所以无需加热设备。此项目所收集到的数据将为这种工艺的发展提供帮助。同时也可以为那些想要减少出泥量的水厂提供一种新的方法。因为它投资小,见效快,操作简单。     

超声波技术在污泥处理利用中的应用现状及前景预测

本文介绍低频超声波技术在城市污水厂污泥处理中应用的原理以及可以带来的经济和环境效益。指出，对一定量的剩余污泥进行超声处理后进行发酵，或者将其回流到生化池进水，可以增加沼气产量，并使最终的泥饼数量减少。通过分析德国的应用实例，说明了超声波设备可以带来的运行成本方面的好处。     

Determination of phosphorus speciation in dairy manure using XRD and XANES spectroscopy

Intensive manure application is an important source of diffuse phosphorus (P) pollution. Phosphorus availability from animal manure is influenced by its chemical speciation. The major objective of this study was to investigate the P speciation in raw and anaerobically digested dairy manure with an emphasis on the calcium (Ca) and magnesium (Mg) phosphate phases. Influent and effluent from an on-farm digester in Wisconsin were sampled and sieved, and the 25 to 53 microm size fraction was dried for X-ray powder diffraction (XRD) and P K-edge X-ray absorption near edge structure (XANES) analyses. Struvite (MgNH4PO4.6H2O) was identified in both the raw (influent) and anaerobically digested (effluent) manure using XRD. Qualitative analysis of P K-edge XANES spectra indicated that the Ca orthophosphate phases, except dicalcium phosphate anhydrous (DCPA) or monetite (CaHPO4), were not abundant in dairy manure. Linear combination fitting (LCF) of the P standard compounds showed that 57.0 and 43.0% of P was associated with DCPA and struvite, respectively, in the raw manure. In the anaerobically digested sample, 78.2% of P was present as struvite and 21.8% of P was associated with hydroxylapatite (HAp). The P speciation shifted toward Mg orthophosphates and least soluble Ca orthophosphates following anaerobic digestion. Similarity between the aqueous orthophosphate (aq-PO4), newberyite (MgHPO4.3H2O), and struvite spectra can cause inaccurate P speciation determination when dairy manure is analyzed solely using P K-edge XANES spectroscopy; however, XANES can be used in conjunction with XRD to quantify the distribution of inorganic P species in animal manure.     

Assessment of metal availability in smelter soil using earthworms and chemical extractions

Chemical immobilization is a relatively inexpensive in situ remediation method that reduces soil contaminant solubility, but the ability of this remediation treatment to reduce heavy metal bioavailability and ecotoxicity to soil invertebrates has not been evaluated. Our objectives were to (i) assess the ability of chemical immobilization amendments (municipal sewage sludge biosolids and rock phosphate) to reduce metal bioavailability and toxicity in a toxic metal-contaminated smelter soil and (ii) evaluate soil extraction methods using Ca(NO3)2 solution or ion-exchange membranes coated with diethylenetriaminepentaacetic acid (DTPA) as surrogate measures of metal bioavailability and ecotoxicity. We treated a soil contaminated by Zn and Pb milling and smelting operations and an uncontaminated control soil with lime-stabilized municipal biosolids (LSB), rock phosphate (RP), or anaerobically digested municipal biosolids (SS) and evaluated lethality of the remediated soils to earthworm (Eisenia fetida Savigny). Lime-stabilized municipal biosolids was the only remediation amendment to successfully immobilize lethal levels of Zn in the smelter soil (14-d cumulative mortality < or = 15%). Calcium nitrate-extractable Zn in the lethal Zn smelter soil-amendment combinations was 11.5 to 18.2 mmol/kg, compared with the nonlethal LSB amended soil (0.62 mmol/kg). The Ca(NO3)2-extractable Zn-based median lethal concentration (LC50) of 6.33 mmol/kg previously developed in Zn-spiked artificial soils was applicable in the remediated smelter soils despite a 14-fold difference in total Zn concentration. Chelating ion-exchange membrane uptake among the soils was highly variable (mean CV = 39%) compared with the Ca(NO3)2-extraction (mean CV = 1.9%) and not well related to earthworm toxicity.     

Methane production during storage of anaerobically digested municipal organic waste

Anaerobic digestion of source-separated municipal organic waste is considered feasible in Denmark. The limited hydraulic retention in the biogas reactor (typically 15 d) does not allow full degradation of the organic waste. Storage of anaerobically digested municipal organic waste can therefore be a source of methane (CH4) emission that may contribute significantly to the potential global warming impact from the waste treatment system. This study provides a model for quantifying the CH4 production from stored co-digested municipal organic waste and estimates the production under typical Danish climatic conditions, thus quantifying the potential global warming impact from storage of the digested municipal organic waste before its use on agricultural land. Laboratory batch tests on CH4 production as well as temperature measurements in eight full-scale storage tanks provided data for developing a model estimating the CH4 production in storage tanks containing digested municipal organic waste. The temperatures measured in separate storage tanks on farms receiving digested slurry were linearly correlated with air temperature. In storage tanks receiving slurry directly from biogas reactors, significantly higher temperatures were measured due to the high temperatures of the effluent from the reactor. Storage tanks on Danish farms are typically emptied in April and have a constant inflow of digested material. During the warmest months the content of digested material is therefore low, which limits the yearly CH4 production from storage.     

污泥高温好氧消化的研究进展

高温好氧消化工艺（Thermophilic Aerobic Digestion--TAD）是一种具有较高的稳定效率和病原菌灭活率的污泥稳定化处理工艺。本文从工艺原理、关键运行参数、处理效果、与中温厌氧结合等方面对高温好氧消化的研究现状进行综述，并对该研究领域中关于VFA（Volatile Fatty Acids）积累、微氧环境生态及运行控制参数等几个研究热点问题进行了分析，供相关的研究者参考。     

Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation

This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L^?1). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption–oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.     

污泥高固体厌氧消化研究进展

厌氧消化是实现污泥的减量化、稳定化和资源化的重要手段,相对于传统的低浓度污泥厌氧消化工艺高固体污泥厌氧消化可以直接利用污水处理厂排放的脱水污泥,具有设施体积小、单位容积产气率较高和水耗及能耗较低等优势。本文综述了近年来污泥高固体消化的研究进展,从污泥高固体厌氧消化的基本特征出发,总结了污泥高固体厌氧消化的影响因素和对反应器的要求;同时对污泥高固体消化存在的搅拌不匀、传质传热困难、有机质降解率偏低、搅拌系统不成熟等问题作了简要分析,这些问题都还有待于深入研究解决。     

污泥农用对土壤环境的影响

土地利用是解决城市污泥处理处置的有效途径之一,本文从土壤理化性质、重金属污染风险以及有机污染风险3方面综述城市污泥农用对土壤环境的影响。城市污泥利用为植物提供营养元素,改良土壤结构,提高土壤肥力。污泥施用年限的长短与土壤中重金属的含量高低关系不明显,导致土壤重金属含量增加的主要因素是污泥施用量和污泥中重金属含量。在正常...     

城市污水厂混合污泥好氧消化处理研究

以城市污水处理厂的初沉污泥与剩余污泥的混合污泥为对象,研究了影响污泥好氧消化处理的各项因素.通过测定氧摄取速率(OUR)和此污泥好氧速率(SOUR),对实验结果进行了探讨.     

Characterization of sewage sludge organic matter using solid-state carbon-13 nuclear magnetic resonance spectroscopy

Six sewage sludges from five sewage treatment plants in Australia were characterized using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Spectra were acquired both before and after removal of mineral components through treatment with hydrofluoric acid (HF). Carbon mass balance indicated that little organic matter was lost on HF treatment, which significantly improved NMR sensitivity and spectral resolution, and decreased acquisition time and hence cost of NMR analysis. Two NMR techniques were used, the standard cross polarization (CP) technique and Bloch decay (BD). The BD technique had not been applied previously to the analysis of sewage sludge. For each sludge sample, both before and after HF treatment, the BD spectrum contained significantly more alkyl carbon. Spin counting, another technique applied to sewage sludge here for the first time, showed that the BD spectra of the HF-treated sludges were quantitative, while approximately 30% of the CP NMR signal went undetected. The discrepancy between CP and BD spectra was attributed to the presence of alkyl carbon with such high molecular mobility that the efficiency of cross polarization is affected. This study shows that sewage sludge organic matter is significantly different in chemistry to soil organic matter and has implications for the application of sewage sludge to agricultural land.