Relation between substrate feeding pattern and development of filamentous bacteria in activated sludge processes: Part III. applications with industrial waste waters

Summary Laboratory scale activated sludge systems were operated under regimes of continuous or intermittent feeding of the waste water. Industrial waste waters from breweries, a dairy plant and a petro-chemical plant were investigated. The systems were started up with sludge from a municipal waste water plant or more often with sludges obtained from the corresponding industrial waste water treatment plants. It was found that intermittently fed systems produced sludges with better settleability characteristics than systems that were continuously supplemented with waste water. Our previous hypothesis that in intermittent systems floc forming bacteria become dominant as a result of higher substrate uptake rates was confirmed and may thus be extended to waste waters containing readily available substrates such as carbohydrates (brewery-and dairy waste water) or acids (petro-chemical waste water). Supplementation of brewery waste water with urea had a negative influence on sludge settleability, especially in continuously operated systems.     

Restoration of the ability to settle bulking sludge by bacterial seeding in wastewater treatment

An attempt to restore the settling ability of denatured bulking sludge was under-taken by changing the microflora in waste treatment tanks. A cell suspension of mixed cultures of ten strains of bacteria, which were isolated from normal activated sludge from night soil plants, and a type culture Zoogloea ramigera IAM1236 was seeded into a laboratory-scale aeration tank containing bulking sludge collected from municipal night soil or a food processing (bean curd production) waste treatment plant. The tank was fed with synthetic wastewater or industrial waste and aerated for 22 days. After 5 days, the microflora in the sludge changed remarkably with the seeding of the bacterial culture; filamentous organisms disappeared and active protozoa (Vorticella sp., Epistylis sp., and Lecane sp.) appeared. The sludge became compact and settled rapidly. The SV₃₀ of the sludge temporarily increased, but in the end decreased from 97 to 20%. The CODcr value decreased from 300 to 20 ppm. In the tank without seeding, the sludge contained almost filamentous organisms only which floated and finally decomposed. The effects were confirmed by applied tests in 700-ton scale and 100-ton scale aeration tanks of municipal night soil and a food processing waste treatment plant, respectively.     

Risk of African swine fever introduction into the European Union through transport-associated routes: returning trucks and waste from international ships and planes

ABSTRACT: BACKGROUND: The uncontrolled presence of African swine fever (ASF) in Russian Federation (RF) poses a serious risk to the whole European Union (EU) pig industry. Although trade of pigs and their products is banned since the official notification in June 2007, the potential introduction of ASF virus (ASFV) may occur by other routes, which are very frequent in ASF, and more difficult to control, such as contaminated waste or infected vehicles. This study was intended to estimate the risk of ASFV introduction into the EU through three types of transport routes: returning trucks, waste from international ships and waste from international planes, which will be referred here as transport-associated routes (TAR). Since no detailed and official information was available for these routes, a semi-quantitative model based on the weighted combination of risk factors was developed to estimate the risk of ASFV introduction by TAR. Relative weights for combination of different risk factors as well as validation of the model results were obtained by an expert opinion elicitation. RESULTS: Model results indicate that the relative risk for ASFV introduction through TAR in most of the EU countries (16) is low, although some countries, specifically Poland and Lithuania, concentrate high levels of risk, the returning trucks route being the analyzed TAR that currently poses the highest risk for ASFV introduction into the EU. The spatial distribution of the risk of ASFV introduction varies importantly between the analyzed introduction routes. Results also highlight the need to increase the awareness and precautions for ASF prevention, particularly ensuring truck disinfection, to minimize the potential risk of entrance into the EU. CONCLUSIONS: This study presents the first assessment of ASF introduction into the EU through TAR. The innovative model developed here could be used in data scarce situations for estimating the relative risk associated to each EU country. This simple methodology provides a rapid and easy to interpret results on risk that may be used for a target and cost-effective allocation of resources to prevent disease introduction.     

Application of continuous oxidative assimilation and endogenous protein synthesis to the treatment of carbohydrate wastes deficient in nitrogen

A synthetic waste (with glucose as carbon source) devoid of a source of nitrogen was purified in a laboratory scale pilot plant by a new modification of the activated sludge process. The process makes use of a separate carbon assimilation (oxidative assimilation) phase and an endogenous phase in which ammonia is added to a portion of the settled sludge and non-nitrogenous products stored in the cells in the assimilation phase are converted to protein. It was found that sludge so treated, when recycled to the assimilation tank, could carry out continuous oxidative assimilation of the waste. Various COD:N ratios were studied. At the highest, 70:1, 90% purificaton efficiency was achieved.     

A new large‐scale manufacturing platform for complex biopharmaceuticals

Complex biopharmaceuticals, such as recombinant blood coagulation factors, are addressing critical medical needs and represent a growing multibillion‐dollar market. For commercial manufacturing of such, sometimes inherently unstable, molecules it is important to minimize product residence time in non‐ideal milieu in order to obtain acceptable yields and consistently high product quality. Continuous perfusion cell culture allows minimization of residence time in the bioreactor, but also brings unique challenges in product recovery, which requires innovative solutions. In order to maximize yield, process efficiency, facility and equipment utilization, we have developed, scaled‐up and successfully implemented a new integrated manufacturing platform in commercial scale. This platform consists of a (semi‐)continuous cell separation process based on a disposable flow path and integrated with the upstream perfusion operation, followed by membrane chromatography on large‐scale adsorber capsules in rapid cycling mode. Implementation of the platform at commercial scale for a new product candidate led to a yield improvement of 40% compared to the conventional process technology, while product quality has been shown to be more consistently high. Over 1,000,000 L of cell culture harvest have been processed with 100% success rate to date, demonstrating the robustness of the new platform process in GMP manufacturing. While membrane chromatography is well established for polishing in flow‐through mode, this is its first commercial‐scale application for bind/elute chromatography in the biopharmaceutical industry and demonstrates its potential in particular for manufacturing of potent, low‐dose biopharmaceuticals. Biotechnol. Bioeng. 2012; 109: 3049–3058. © 2012 Wiley Periodicals, Inc.     

Excess sludge reduction by biological way: from experimental experience to a real full scale application

The aim of this study was to investigate the ability of a biological process applied in the sludge line and based on the alternation of oxic and anoxic phases, to minimize the waste sludge production. After some tests in pilot scale, the process was applied in a real municipal wastewater treatment plant of 35,000 PE trying out one setting of working experimental conditions. A rate of the recycle flow was conditioned in a treatment basin, maintaining an HRT of 10 days. The control device operated for the 50% of time in the ORP range between -400 and -200 mV, and for the 50% in the ORP range between -200 and +50 mV. The mass balance defined an actual observed growth yield equal to 0.09 kgTVSkgCODr(-1), and the heterotrophic yield values, assessed by batch tests, seemed to be a suitable marker for the sludge reduction and for the energy uncoupling.     

Ozonation strategies to reduce sludge production of a seafood industry WWTP

In this work, several alternatives related to the application of ozone in different streams of a seafood industry WWTP were evaluated to minimize the production of waste sludge. The WWTP was composed of two coagulation-flocculation units and a biological unit and generated around of 6550 kg/d of sludge. Ozone was applied to sludge coming from flotation units (110 g TSS/L) at doses up to 0.03 g O(3)/g TSS during batch tests, no solids solubilization being observed. Ozone doses ranging from 0.007 to 0.02 g O(3)/g TSS were also applied to the raw wastewater in a bubble column reaching a 6.8% of TSS removal for the highest ozone dose. Finally, the effect of the pre-ozonation (0.05 g O(3)/g TSS) of wastewater coming from the first flotation unit was tested in two activated sludge systems during 70 days. Ozonation caused a reduction of the observed yield coefficient of biomass from 0.14 to 0.07g TSS/g COD(Tremoved) and a slight improvement of COD removal efficiencies. On the basis of the capacity for ozone production available in the industry, a maximum reduction of sludge generated by the WWTP of 7.5% could be expected.     

厌氧消化污泥微生物组研究方法及应用

污泥厌氧消化是在消化污泥微生物组的协调下将剩余污泥中有机物转化为甲烷的微生物过程。与传统厌氧消化过程不同,污泥厌氧消化系统的进料底物为含有大量微生物细胞及胞外多聚物等复杂大分子有机物的剩余污泥。因此,厌氧消化污泥微生物组的种群组成、功能及种群间互作关系等异常复杂,使厌氧消化污泥微生物组分析成为难点问题。但近年来高通量测序技术及生物信息学分析方法的快速发展为消化污泥微生物组研究提供了契机,并迅速推动了该研究领域的发展。本文从4个方面梳理、总结厌氧消化污泥微生物组的研究及应用现状:剩余活性污泥结构、组成及其厌氧消化;基于16SrRNA基因序列测序的微生物组研究;基于宏基因组及宏转录组分析的微生物组研究;厌氧消化污泥微生物组研究案例分析。最后我们提出了厌氧消化污泥微生物组研究亟待解决的关键科学问题。     

Modification of Fertility of Soil Materials for Restoration of Acid Grassland Habitat

Use of composts for habitat restoration offers advantages in terms of efficient use of resources. Chemical amendment of compost to reduce its pH and P availability was investigated in order to improve suitability for use in reclamation of blocky quarry waste to acidic grassy heathland. The effect of these amendments was observed on competition between two grass species: Agrostis capillaris and Festuca ovina. A factorial, pot‐scale greenhouse experiment was set up using two composts (one a mixture of green waste and catering waste, and the other a mixture of green waste and sewage sludge). In addition, two soils were collected from upland acidic grassland to provide a natural comparison. S⁰ was applied to reduce soil pH, and Fe(OH)₃ from a coal waste treatment plant was applied to counteract the expected increase in P availability due to acidification of the composts by S⁰. Addition of S⁰ significantly reduced soil solution pH and addition of Fe(OH)₃ significantly reduced soil solution P concentration. In one compost S⁰ reduced the biomass of F. ovina while increasing that of A. capillaris, whereas Fe(OH)₃ had no significant effect on the biomass of either species. Although S⁰ and Fe(OH)₃ did adjust the chemical properties of the soil solution, Fe(OH)₃ did not bind P strongly enough to make it unavailable to plants. Further work is required, however, the use of chemically amended composts provides a sustainable sink for organic wastes and we conclude from this study that they have great potential for large‐scale restoration of blocky waste tips.     

Inoculum selection influences the biochemical methane potential of agro-industrial substrates

Obtaining a reliable estimation of the methane potential of organic waste streams in anaerobic digestion, for which a biochemical methane potential (BMP) test is often used, is of high importance. Standardization of this BMP test is required to ensure inter-laboratory repeatability and accuracy of the BMP results. Therefore, guidelines were set out; yet, these do not provide sufficient information concerning origin of and the microbial community in the test inoculum. Here, the specific contribution of the methanogenic community on the BMP test results was evaluated. The biomethane potential of four different substrates (molasses, bio-refinery waste, liquid manure and high-rate activated sludge) was determined by means of four different inocula from full-scale anaerobic digestion plants. A significant effect of the selected inoculum on the BMP result was observed for two out of four substrates. This inoculum effect could be attributed to the abundance of methanogens and a potential inhibiting effect in the inoculum itself, demonstrating the importance of inoculum selection for BMP testing. We recommend the application of granular sludge as an inoculum, because of its higher methanogenic abundance and activity, and protection from bulk solutions, compared with other inocula.     

Assessment of the degree of electrochemical treatment of sewage using biotesting

Studies were conducted on estimation of the toxicity levels in various oxygen-containing chlorine compounds formed during electrochemical treatment of sewage by using a culture isolated from activated sludge purifying antibiotic production waste. It was shown that the products formed during electrocatalytic treatment of solutions (concentration of NaCl 1.5-5 g/l, pH 2.0-12.0, volumetric current density up to 10 A/l) were not toxic and stimulated the growth of P. fluorescens.     

Control of Microthrix parvicella growth in activated sludge

Abstract Effects of aerobic and anaerobic conditions on the growth of Microthrix parvicella in the activated sludge were studied to prevent bulking caused by this filamentous bacterium. The study was conducted on a pilot plant with selector and the data were compared with those observed in a full scale plant subjected to severe bulking due to a massive growth of M. parvicella . Both plants were fed with the same settled waste water. A substantial suppression of the growth of M. parvicella was observed in only the experiments where returned activated sludge was mixed with waste water under aerobic conditions. Both the number of filaments and the sludge volume index (SVI) were lower in the pilot plant than in the full scale plant. Under anerobic conditions, the selector was not able to improve the settleability and avoid the growth of M. parvicella .     

Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions - a review

Heavy metal remediation of aqueous streams is of special concern due to recalcitrant and persistency of heavy metals in environment. Conventional treatment technologies for the removal of these toxic heavy metals are not economical and further generate huge quantity of toxic chemical sludge. Biosorption is emerging as a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The major advantages of biosorption over conventional treatment methods include: low cost, high efficiency, minimization of chemical or biological sludge, regeneration of biosorbents and possibility of metal recovery. Cellulosic agricultural waste materials are an abundant source for significant metal biosorption. The functional groups present in agricultural waste biomass viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. have affinity for heavy metal ions to form metal complexes or chelates. The mechanism of biosorption process includes chemisorption, complexation, adsorption on surface, diffusion through pores and ion exchange etc. The purpose of this review article is to provide the scattered available information on various aspects of utilization of the agricultural waste materials for heavy metal removal. Agricultural waste material being highly efficient, low cost and renewable source of biomass can be exploited for heavy metal remediation. Further these biosorbents can be modified for better efficiency and multiple reuses to enhance their applicability at industrial scale.     

Purification of coal gasification combined with brewery waste waters in upflow anaerobic sludge blanket digesters

Laboratory-scale upflow anaerobic sludge blanket (UASB) digesters containing granular sludge adapted to brewery effluent were fed increasing concentrations of artificial coal gasification (CG) waste water in brewery effluent and were effective at purifying this combined waste water up to a CG effluent concentration of 15%. At higher CG waste water concentrations and flow rates, performance declined rapidly.     

Anaerobic digestion of long-chain fatty acids in UASB and expanded granular sludge bed reactors

Solutions of sodium caprate and sodium laurate were digested in upflow anaerobic sludge bed (UASB) reactors inoculated with granular sludge and in expanded granular sludge bed (EGSB) reactors. UASB reactors are unsuitable if lipids contribute 50% or more to the COD of waste water: the gas production rate required to obtain sufficient mixing and contact cannot be achieved. At lipid loading rates exceeding 2–3 kg COD m⁻³ day⁻¹, total sludge wash-out occurred. At lower loading rates the system was unreliable, due to unpredictable sludge flotation. EGSB reactors do fulfil the requirements of mixing and contact. They accommodate space loading rates up to 30 kg COD m⁻³ day⁻¹ during digestion of caprate or laurate as sole substrate, at COD removal efficiencies of 83–91%, and can be operated at hydraulic residence times of 2 h without any problems. Augmentation of granular sludge in lab-scale EGSB reactors was demonstrated. The new granules had excellent settling properties. Floating layer formation, as well as mixing characteristics in full-scale EGSB reactors require further research.     

Aerobic biotransformation of 4-fluorocinnamic acid to 4-fluorobenzoic acid

The biotransformation of 4-fluorocinnamic acid (FCA) using non-acclimated industrial activated sludge was investigated. FCA is a common intermediate in organic synthesis, and it is often present in aqueous waste streams. Hence, the biotransformation reactions this compound undergoes when exposed to activated sludge micro-organisms should be understood before waste streams are sent to biological wastewater treatment plants (WWTPs). FCA biotransformation was monitored using a wide range of analytical techniques. These techniques were used to monitor not only FCA disappearance, but also the formation of degradation products, in order to propose the metabolic pathway. FCA was biotransformed to 4-fluorobenzoic acid via the formation of 4-fluoroacetophenone. The removal of FCA up to 200 mg L^-1 followed first order kinetics. The half-lives for removal of FCA from the test solutions supplied with 200 mg L^-1, 100 mg L^-1, and 50 mg L^-1 were 53, 18, and 5 hours respectively.     

Increased power generation from primary sludge by a submersible microbial fuel cell and optimum operational conditions

Microbial fuel cells (MFCs) have received attention as a promising renewable energy technology for waste treatment and energy recovery. We tested a submersible MFC with an innovative design capable of generating a stable voltage of 0.250 ± 0.008 V (with a fixed 470 Ω resistor) directly from primary sludge. In a polarization test, the maximum power density was 0.18 W/m² at a current density of 0.8 A/m² with an external resistor of 300 Ω. The anodic solution of the primary sludge needs to be adjusted to a pH 7 for high power generation. The modified primary sludge with an added phosphate buffer prolonged the current generation and increased the power density by 7 and 1.5 times, respectively, in comparison with raw primary sludge. These findings suggest that energy recovery from primary sludge can be maximized using an advanced MFC system with optimum conditions.     

Application of UASB-reactors to industrial waste-water treatment; performance data and results in granulation control

Several types of high organic matter pollutants containing (COD-range: 3–50 kg · m^?3) industrial waste waters were treated in laboratory scale (1.2–23 dm³) sludge blanket (UASB) and UASB-fixed bed hybrid (UBF) reactors. In most cases higher than 80% of COD-removal efficiency has been attained. The CO₂ content of the biogas developed was mainly influenced by the neutralization (base to acid) ratio related to feed pH. Cell immobilization by granule formation was considered as a change in microbial population: enrichment and aggregate formation of Methanotrix-like filamentous microorganisms. Based on physiological and physical indexes of microbial selection and with regard to the different sensitivities of microorganisms to substrate inhibition, a new start-up method was developed for rapid (40–45 days) granulation of raw digested sludge.     

Cultivation of low-temperature (15°C), anaerobic, wastewater treatment granules

Aims: Anaerobic sludge granules underpin high‐rate waste‐to‐energy bioreactors. Granulation is a microbiological phenomenon involving the self‐immobilization of several trophic groups. Low‐temperature anaerobic digestion of wastes is of intense interest because of the economic advantages of unheated bioenergy production technologies. However, low‐temperature granulation of anaerobic sludge has not yet been demonstrated. The aims of this study were to (i) investigate the feasibility of anaerobic sludge granulation in cold (15°C) bioreactors and (ii) observe the development of methanogenic activity and microbial community structure in developing cold granules. Methods and Results: One mesophilic (R1; 37°C) and two low‐temperature (R2 and R3, 15°C) laboratory‐scale, expanded granular sludge bed bioreactors were seeded with crushed (diameter <0·4 mm) granules and were fed a glucose‐based wastewater for 194 days. Bioreactor performance was assessed by chemical oxygen demand removal, biogas production, granule growth and temporal methanogenic activity. Granulation was observed in R2 and R3 (up to 33% of the sludge). Elevated hydrogenotrophic methanogenesis was observed in psychrophilically cultivated biomass, but acetoclastic methanogenic activity was also retained. Denaturing gradient gel electrophoresis of archaeal 16S rRNA gene fragments indicated that a distinct community was associated with developing and mature granules in the low‐temperature (LT) bioreactors. Conclusions: Granulation was observed at 15°C in anaerobic bioreactors and was associated with H₂/CO₂‐mediated methanogenesis and distinct community structure development. Significance and Impact of the Study: Granulation underpins high‐rate anaerobic waste treatment bioreactors. Most LT bioreactor trials have employed mesophilic seed sludge, and granulation <20°C was not previously documented.     

Enzymatic treatment of primary municipal sludge with Trichoderma viride cellulase

Enzymatic hydrolysis of the cellulose in raw primary settled municipal sludge by Trichoderma viride cellulase achieved conversions of up to 75% of the cellulose, primarily to cellobiose, in 24 hr. Simultaneously the gel-like characteristic of raw primary sludge was changed to that of a slurry of fine particles in less than 2 hr, causing a radical change in the ability to ultrafilter the sludge. The use of raw primary sludge as a growth medium for T. viride cellulase production was also investigated. It was possible, with nitrogen supplements, to obtain an enzyme with a filter paper activity (FPA) of two compared to over four which is attainable on defined medium of similar strength. The potential use of cellulase treatment as a pretreatment or integral part of waste treatment processes is discussed and the alternatives evaluated.