Industrial Treatment Plant Research Articles

Instruments économiques de politique environnementale et choix technique du pollueur. Le traitement des eaux résiduaires dans l'industrie de vinification

Economic instruments for environmental policy and polluter's technical choice. Wastewater abatement in the wine industry Winery wastewater pollution can be reduced by a Water Agency through economic instruments such as taxes and subsidies. According to the «efficiency without optimally» approach, which aims at reaching a sub-optimal environmental objective at the lowest cost to Society, these instruments should act as an incentive for firms to adopt the best available pollution control technology. As there exists little knowledge of pollution damage functions, the computation of the water agencies' pollution charges is based on pollution abatement costs instead. In order to determine the level of charges, the Water Agency first computes the necessary expenses in terms of investment subsidies (for public and industrial treatment plants) and then determines the costs required to balance its budget. In defining its policy objectives, the Water Agency acts under conditions of information asymmetry. For instance, the Agency does not really know the pollution abatement cost at the sector level or for different kinds of technology. As a result, its policy, although effective because pushing the producers to invest, is inefficient : the cost to Society is higher than the lowest possible cost, and there is a poor redistribution of subsidies among the polluters. In order to reduce this asymmetry of information of the Water Agency (regarding pollution costs), we propose a sector-based approach. This paper studies the wine producers' response — his choice of a wastewater abatement technology — to the use of economic instruments defined by the Water Agency in the south of France. It is assumed that the producers/polluters behave rationally and minimise their pollution control costs. In the second part of the paper, we will look at the individual firm, underlying the importance of fixed costs for the choice of a wastewater control strategy. Consequently we will propose a modified model of polluter's behaviour in which fixed costs are considered and the underlying cost function follows the law of diminishing returns. The analysis of the individual choice between bearing pollution abatement costs (technical investment) and paying pollution costs (taxes) allows us to examine, in addition, the possibility of a partial treatment of wastewater.

In Situ Size Distribution of Suspended Particles in the Fraser River

Size distributions of suspended sediment particles under low flow conditions in the Fraser River were measured using a submersible laser instrument. By comparing the in situ size distribution measured using this instrument with the size distribution of primary particles (measured by collecting sediment samples and analyzing them for size distribution after dispersing the particles by ultrasonic vibration), it was concluded that suspended sediment particles in the Fraser River downstream of pulp mill effluent outfalls are transported as agglomerations of particles (flocs) rather than as individual particles. Flocculation of river sediments in estuaries has been investigated in earlier studies, which show that saltwater intrusion contributes to the flocculation mechanism. Freshwater flocculation, such as the one observed in the present study, also has been reported in the literature, and it is attributed to the presence of organic materials and other contaminants from industrial and sewage treatment plant effluents. This paper describes the details of the submersible laser instrument and its use in the Fraser River, British Columbia, Canada.

Substances with estrogenic activity in effluents of sewage treatment plants in southwestern Germany. 1. Chemical analysis

A gas chromatography/mass spectrometry method for the simultaneous quantitative determination of natural and synthetic estrogens (17beta-estradiol, estrone, 17alpha-ethinylestradiol, and mestranol), phytoestrogens (genistein and beta-sitosterol), and xenoestrogens (benzyl butyl phthalate, dibutyl phthalate, bisphenol A, 4-nonylphenol [NP], 4-nonylphenoxyacetic acid [NP1EC], 4-nonylphenol diethoxylate [NP2EO], and alpha-endosulfan) in effluents of sewage treatment plants (STPs) was developed. Identification and quantification were carried out with the standard addition method using analyte-specific and, in some cases, deuterium-labeled internal standards. The effluents of 18 STPs were investigated. Apart from alpha-endosulfan and mestranol, all selected substances were detected in the majority of samples. The median concentrations of steroidal estrogens were between 0.4 ng/L (17alpha-ethinylestradiol) and 1.6 ng/L (17beta-estradiol). The metabolites of the nonylphenol polyethoxylates, NP, NPIEC, and NP2EO were found in concentrations ranging from the upper-ng/L-range (NP) to the lower-microg/L range (NP1EC). For all substances except mestranol and alpha-endosulfan, median values were calculated and compared to the results of other investigations in Europe and the United States. Possible dependencies of measured concentrations on the geographical location, the capacity, the influent composition, and the technical fitting of the STPs are discussed.

Substances with estrogenic activity in effluents of sewage treatment plants in southwestern Germany. 2. Biological analysis

The proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-Screen assay) was applied for quantitative determination of total estrogenic activity in 24-h composite effluent samples from 16 municipal and two industrial sewage treatment plants (STPs) in the state of Baden-Württemberg, southwestern Germany. The estrogenic efficacy relative to the positive control, 17beta-estradiol, was between 26 and 74% (median, 48%) for the 16 municipal STPs. Estradiol equivalent concentrations (EEQs) were between 0.2 and 7.8 ng/L (median, 1.6 ng/L) and, thereby, were lower than those found in a pilot study, which revealed EEQs of greater than 10 ng/L in the effluents of two other STPs. The EEQs in 14 of the 16 effluent samples were very similar (0.9-3.3 ng/L), indicating a rather constant input of estrogenic substances via STPs into rivers. Additional activated charcoal filtration turned out to be very efficient in further eliminating estrogenic activity from effluents. The EEQs of the E-Screen assay and those calculated from the results of extensive chemical analysis using the estradiol equivalency factors determined for 13 natural and synthetic estrogenic substances were comparable for most of the effluent samples. 17beta-Estradiol, 17alpha-ethinylestradiol, and, to a lesser extent, estrone contributed to 90% or more of the EEQ value.

Feasibility of a multi-component additive for efficient control of activated sludge filamentous bulking

Instantaneous improvement of the settling of bulking filamentous activated sludge can be achieved by the addition of a polymer or a large amount (up to 100% of the MLSS concentration) of talc powder to the sludge. Long-term improvement relies on repeated additions, as these additives have no adverse effects on the causative filaments. A multi-component additive was compared to the traditional additives in lab-scale activated sludge units using three highly filamentous sludges from different industrial treatment plants. The study demonstrated that the multi-component additive was superior to the traditional remedies. It was shown that, in the case of severe filamentous bulking, a single addition of the new additive immediately improved sludge settling and exerted a destructive effect on the causative filamentous bacteria. Thus, the latter additive also ensured a long-term sludge sedimentation improvement. The traditional additives exhibited an immediate and short-term effect. The novel additive also retarded sludge rising due to denitrification and it improved sludge dewaterability. The study revealed Nostocoida limicola II, with slightly hydrophobic cell wall, to be somewhat resistant to the quaternary ammonium salt present as biocide in the additive.

Ecological and physiological analyses of Pseudomonad species within a phenol remediation system

A diverse collection of 700 bacteria obtained from an operational phenolic remediating industrial treatment plant was made to select potential strains as microbial biosensors. Pseudomonads were the most abundant group, of which 48 selected from the liquor or suspended solids were assessed for their physiological response to phenolic pollutant loading and niche specialisation. By FAME-MIS identification the Pseudomonads were clustered into six major species groups. Those isolates able to utilise phenol as a sole carbon source predominantly belonged to a non-clonal Pseudomonas pseudoalcaligenes cluster determined by REP-PCR genotyping. Rapid microtitre based respiration assays were developed to contrast activity in response to increasing concentrations of phenol. A considerable range in response for both phenol degrader and non-degrader strains was observed. This natural phenotypic and physiological heterogeneity could facilitate the selection of isolates for the development of a suite of ecologically relevant, custom designed sensors with predictable toxicity susceptibilities to monitor process efficacy.

In Situ Size Distribution of Suspended Particles in the Fraser River

Size distributions of suspended sediment particles under low flow conditions in the Fraser River were measured using a submersible laser instrument. By comparing the in situ size distribution measured using this instrument with the size distribution of primary particles (measured by collecting sediment samples and analyzing them for size distribution after dispersing the particles by ultrasonic vibration), it was concluded that suspended sediment particles in the Fraser River downstream of pulp mill effluent outfalls are transported as agglomerations of particles (flocs) rather than as individual particles. Flocculation of river sediments in estuaries has been investigated in earlier studies, which show that saltwater intrusion contributes to the flocculation mechanism. Freshwater flocculation, such as the one observed in the present study, also has been reported in the literature, and it is attributed to the presence of organic materials and other contaminants from industrial and sewage treatment plant effluents. This paper describes the details of the submersible laser instrument and its use in the Fraser River, British Columbia, Canada.

Application of low pressure nanofiltration membranes for the recovery and reuse of dairy industry effluents

This paper outlines the requirements for water reuse of dairy industry treatment plant effluents. Two alternative membrane processes are described. Nanofiltration (NF) membranes were applied to the existing treatment plant effluents in the first part of the study. NF membranes were used in different operating conditions. Successive batch runs had shown that serious membrane fouling appeared not to be a problem with treatment plant effluents. Excellent rejections have been achieved. It will be possible to recover approximately 90% of the treatment plant effluent for reuse. Heavy metal removal was also very high. In the second part of the study, two pass reverse osmosis (RO) membranes were applied to the raw wastewater of the dairy industry. RO experiments demonstrated that two-pass RO produce permeate of very good quality. Almost complete COD removals were achieved and flux values decreased slightly during the each RO run.

Fate of Conventional/Priority Organic Pollutants Associated with Wastewater Reuse in Soil Irrigation in Kuwait

Soil contamination from conventional/priority organic pollutants associated the reuse of wastewater for agricultural irrigation in selected sites in Kuwait is assessed in this paper using a laboratory pilot plant designed for this purpose. The permeated wastewaters included industrial and tertiary treated wastewaters from different industrial and wastewater treatment plants in Kuwait. Tab (potable) water will be also used as a reference base. The investigated soil sites covered representative agricultural areas in Kuwait including Al-Wafra, Al-Abdally and Sulaibiya agricultural sites. The soil characteristics in these sites are presented. The preliminary results of pilot plant tests for Abdally area soils are discussed herein and related conclusions and remarks are outlined.

Anaerobic Treatment of Polyethylene Terephthalate (PET) Wastewater from Lab to Full Scale

In the last decade Polyethylene Terephthalate (PET) production is growing. The wastewater of the “Catalana de Polimers” factory in Barcelona (Spain) has two main streams of similar flow rate, esterification (COD=30,000 mg/l) and textile (COD=4000 mg/l). In order to assess the anaerobic treatment viability, discontinuous and continuous experiments were carried out. Discontinuous biodegradability tests indicated that anaerobic biodegradability was 90 and 75% for esterification and textile wastewater. The textile stream revealed some tendency to foam formation and inhibitory effects. Nutrients, micronutrients and alkali limitations and dosage were determined. A continuous lab-scale UASB reactor was able to treat a mixture of 50% (v) esterification/textile wastewater with stable behaviour at organic loading rate larger than 12 g COD/l.d (0.3 g COD/g VSS.d) with COD removal efficiency greater than 90%. The start-up period was very short and the recuperation after overloading accidents was quite fast, in spite of the wash-out of solids. From the laboratory information an industrial treatment plant was designed and built, during the start-up period COD removal efficiencies larger than 90% and organic loading rate of 0.6 kg COD/kg VSS.d (5 kg COD/m3.d) have been reached.

A feasibility study on ultrafiltration of industrial effluents

Short-term membrane tests were carried out to determine the feasibility of the application of ultrafiltration for the reuse of effluent from industrial treatment plants. Ultrafiltration proved to be a suitable technology for the treatment and reuse of effluent and with dead-end filtration high permeate fluxes were achieved. An adequate cleaning procedure for the membranes is required to maintain constant and high permeate fluxes. The feasibility is partly determined by the suspended solids concentration in the effluent. For the recirculation of effluent with low suspended solid concentrations the operational costs are comparable to or lower than the costs of drinking water and groundwater. If a high temperature of the process water is required and the thermal energy in the effluent can be reused, an additional saving can be obtained in the total costs per cubic metre water. The technical feasibility of the reuse of effluent depends on the type of industry, the wastewater characteristics and the required permeate quality for reuse. The economic feasibility of effluent reuse will be determined by the present water price, trends in the costs of drinking water or abstraction of groundwater and further developments in the costs of membrane technology.

A feasibility study on ultrafiltration of industrial effluents

Short-term membrane tests were carried out to determine the feasibility of the application of ultratiltration for the reuse of effluent from industrial treatment plants. Ultrafiltration proved to be a suitable technology for the treatment and reuse of effluent and with dead-end filtration high permeate fluxes were achieved. An adequate cleaning procedure for the membranes is required to maintain constant and high permeate fluxes. The feasibility is partly determined by the suspended solids concentration in the effluent. For the recirculation of effluent with low suspended solid concentrations the operational costs are comparable to or lower than the costs of drinking water and groundwater. If a high temperature of the process water is requimd and the thermal energy in the effluent can be reused, an additional saving can be obtained in the total costs per cubic metre water. The technical feasibility of the reuse of efflluent depends on the type of industry, the wastewater characteristics and the required permeate quality for reuse. The economic feasibility of effluent reuse will be determined by the present water price, trends in the costs of drinhing water or abstraction of groundwater and further developments in the costs of membrane technology.

Fate of conventional/priority organic pollutants associated with wastewater reuse in soil irrigation in Kuwait

Soil contamination from conventional/priority organic pollutants associated the reuse of wastewater for agricultural irrigation in selected sites in Kuwait is assessed in this paper using a laboratory pilot plant designed for this purpose.The permeated wastewaters included industrial and tertiary treated wastewaters from different industrial and wastewater treatment plants in Kuwait. Tab (potable) water will be also used as a reference base.The investigated soil sites covered representative agricultural areas in Kuwait including Al-Wafra, Al-Abdally and Sulaibiya agricultural sites. The soil characteristics in these sites are presented.The preliminary results of pilot plant tests for Abdally area soils are discussed herein and related conclusions and remarks are outlined.

Compound parabolic concentrator technology development to commercial solar detoxification applications

An EC-DGXII BRITE-EURAM-III-financed project called ‘Solar detoxification technology in the treatment of persistent non-biodegradable chlorinated industrial water contaminants’ is described. The objectives are to develop a simple, efficient and commercially competitive solar water treatment technology based on compound parabolic collectors (CPC) enabling design and erection of turnkey installations. A European industrial consortium, SOLARDETOX, representing industry and research in Spain, Portugal, Germany and Italy has been created through this project. Some of the most up-to-date scientific and technological results are given, including the design of the first industrial European solar detoxification treatment plant, the main project deliverable.

Anaerobic treatment of polyethylene terephthalate (PET) wastewater from lab to full scale

In the last decade Polyethylene Terephthalate (PET) production is growing. The wastewater of the “Catalana de Polimers” factory in Barcelona (Spain) has two main streams of similar flow rate, esterification (COD=30,000 mg/l) and textile (COD=4000 mg/l). In order to assess the anaerobic treatment viability, discontinuous and continuous experiments were carried out. Discontinuous biodegradability tests indicated that anaerobic biodegradability was 90 and 75% for esterification and textile wastewater. The textile stream revealed some tendency to foam formation and inhibitory effects. Nutrients, micronutrients and alkali limitations and dosage were determined. A continuous lab-scale UASB reactor was able to treat a mixture of 50% (v) esterification/textile wastewater with stable behaviour at organic loading rate larger than 12 g COD/l.d (0.3 g COD/g VSS.d) with COD removal efficiency greater than 90%. The start-up period was very short and the recuperation after overloading accidents was quite fast, in spite of the wash-out of solids. From the laboratory information an industrial treatment plant was designed and built, during the start-up period COD removal efficiencies larger than 90% and organic loading rate of 0.6 kg COD/kg VSS.d (5 kg COD/m 3 .d) have been reached.

98/03885 A concentrated parameter model for fluid-bed flash pyrolysis of biomass

Sewage sludge is the residue produced by the domestic or industrial wastewaters treatment plants. According to the principles of sustainability, several restrictions have been imposed on the conventional methods currently adopted for its disposal. The consequent need to develop alternative processes for the use of sewage sludge for energy purposes such as gasification requires experimental tests in order to quantify the potential energy recover from this waste, as well as to evaluate the optimum conditions for its gasification. In the present study, the gasification with air of dehydrated sewage sludge (20 wt.% moisture) mixed with conventional woody biomass was performed in a pilot scale updraft fixed-bed gasifier operating at atmospheric pressure. Attention was focused on the effect of the sewage sludge content and the equivalent ratio (ratio between the amount of air used and the stoichiometric air needed for combustion) on the product yields, gas composition and cold gas efficiency.The results obtained showed that it is possible to cogasify sewage sludge with wood pellets in pre-existing updraft fixed-bed gasification installations. However, at high sewage sludge content (⩾70 w/w%) slagging and an excessive clinker formation may occur in the oxidation zone because of the high ash content and low ash fusion temperatures of the sludge making the gasification process unstable. In addition, the formation of an ash layer on the grate requires persistent ash discharge that introduces instabilities in the gasifier operating conditions.The rise in the equivalent ratio led to higher gas and carbon yields and cold gas efficiencies. At the optimal equivalent ratio of 0.25, compared with wood pellets gasification, the addition of sewage sludge with 20 wt.% moisture up to 70 w/w% gave rise to decreasing the dry gas yield from 1.56 to 1.07 Nm3/kg of feedstock due to the higher moisture and ash content of sewage sludge and to moderate reductions of the gas lower heating value and cold gas efficiency from 5.8to4.9MJ/Nmdry3 and from 60% to 55%, respectively.

The effect of cationic salt addition on the settling and dewatering properties of an industrial activated sludge

Cations have been found to influence the settling and dewatering properties of activated sludge, especially for industrial wastewaters in which very high concentrations of monovalent cations are often found. Because the cation content of wastewaters is often influenced by upstream processes, an understanding of the influence of various cations can be an important consideration in pinpointing operational problems in wastewater treatment plants. An industrial activated‐sludge treatment plant was studied to determine whether variations in settling and dewatering properties of the mixed liquor and waste solids could be caused by changes in the cation content of the wastewater. Laboratory reactors received both return activated sludge and wastewater from the industrial treatment plant, and the feed was supplemented with either sodium (Na+), potassium (K+), or magnesium (Mg+). It was found that when the monovalent‐to‐divalent (M:D) cation ratio on a milliequivalent basis was increased to greater than approximately 2:1 by either Na+ or K+ addition, dewatering properties became poorer and polymer conditioning requirements increased. The soluble protein content also increased as the mixed liquor M:D ratio increased, indicating release of biopolymer from the flocs. Magnesium addition at low doses caused a decrease in the dewatering rate, but at higher doses both the settling and dewatering properties of waste solids improved substantially. Conversely, when Na+ and K+ concentrations in the raw wastewater decreased significantly to less than 10 and 0.1 milliequivalents (meq), respectively, settling and dewatering properties improved substantially and addition of Mg2+ did not improve conditions beyond those of the unamended control. Each of the cations studied caused unique changes in the properties of activated‐sludge solids that could not be correlated with the M:D ratio, suggesting that some of the effects are not simply physical/chemical but may be physiological as well.

Combining fluorescent in situ hybridization (fish) with cultivation and mathematical modeling to study population structure and function of ammonia-oxidizing bacteria in activated sludge

16S rRNA-targeted oligonucleotide probes for phylogenetically defined groups of autotrophic ammonia-oxidizing bacteria were used for analyzing the natural diversity of nitrifiers in an industrial sewage treatment plant receiving sewage with high ammonia concentrations. In this facility discontinuous aeration is used to allow for complete nitrification and denitrification. In situ hybridization revealed a yet undescribed diversity of ammonia oxidizers occurring in the plant. Surprisingly, the majority of the ammonia oxidizers were detected with probe combinations which indicate a close affiliation of these cells with Nitrosococcus mobilis. In addition, low numbers of ammonia-oxidizers related to the Nitrosomonas europaea - Nitrosomonas eutropha cluster were present. Interestingly, we also observed hybridization patterns which suggested the occurrence of a novel population of ammonia oxidizers. Confocal laser scanning microscopy revealed that all specifically stained ammonia oxidizers were clustered in microcolonies formed by rod-shaped bacteria. Combination of FISH and mathematical modeling was used to investigate diffusion limitation of ammonia and O2 within these aggregates. Model simulations suggest that mass transfer limitations inside the clusters are not as significant as the substrate limitations due to the activity of surrounding heterotrophic bacteria. To learn more about the ammonia-oxidizers of the industrial plant, we enriched and isolated ammonia-oxidizing bacteria from the activated sludge by combining classical cultivation techniques and FISH. Monitoring the isolates with the nested probe set allowed us to specifically identify those ammonia oxidizers which were found in situ to be numerically dominant. The phylogenetic relationship of these isolates determined by comparative 16S rDNA sequence analysis confirmed the affiliation suggested by FISH.

Combining fluorescent in situ hybridization (fish) with cultivation and mathematical modeling to study population structure and function of ammonia-oxidizing bacteria in activated sludge

16S rRNA-targeted oligonucleotide probes for phylogenetically defined groups of autotrophic ammonia-oxidizing bacteria were used for analyzing the natural diversity of nitrifiers in an industrial sewage treatment plant receiving sewage with high ammonia concentrations. In this facility discontinuous aeration is used to allow for complete nitrification and denitrification. In situ hybridization revealed a yet undescribed diversity of ammonia oxidizers occurring in the plant. Surprisingly, the majority of the ammonia oxidizers were detected with probe combinations which indicate a close affiliation of these cells with Nitrosococcus mobilis. In addition, low numbers of ammonia-oxidizers related to the Nitrosomonas europaea - Nitrosomonas eutropha cluster were present. Interestingly, we also observed hybridization patterns which suggested the occurrence of a novel population of ammonia oxidizers. Confocal laser scanning microscopy revealed that all specifically stained ammonia oxidizers were clustered in microcolonies formed by rod-shaped bacteria. Combination of FISH and mathematical modeling was used to investigate diffusion limitation of ammonia and O2 within these aggregates. Model simulations suggest that mass transfer limitations inside the clusters arc not as significant as the substrate limitations due to the activity of surrounding heterotrophic bacteria. To learn more about the ammonia-oxidizers of the industrial plant, we enriched and isolated ammonia-oxidizing bacteria from the activated sludge by combining classical cultivation techniques and FISH. Monitoring the isolates with the nested probe set allowed us to specifically identify those ammonia oxidizers which were found in situ to be numerically dominant. The phylogenetic relationship of these isolates determined by comparative 165 rDNA sequence analysts confirmed the affiliation suggested by FISH.

Modeling and optimization of a municipal treatment plant using enviropro designer

AbstractThe increasingly stringent environmental regulations on discharge standards have rendered the optimal design and operation of industrial and municipal treatment plants a challenging task. The new regulations require tracking and control of VOCs and heavy metals if such chemicals are present in the influent stream. Further, they require more effective removal of nutrients (organic nitrogen, and phosphorus). To address the above issues at our facility, EnviroPro Designer, a comprehensive environmental simulator from Intelligen, Inc., was used to model and analyze our wastewater treatment plant. The work was performed in two phases. In phase one, we developed and validated a model of the existing facility. In phase two, we carried out sensitivity analysis and evaluated a number of process modification scenarios. This paper will describe the findings of our modeling work and our experience from using EnviroPro Designer.