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Enhancement of the biodegradability of model wastewater containing recalcitrant or inhibitory chemical compounds by photocatalytic pre-oxidation.

m-Dinitrobenzene, diphenylamine and resorcinol, three aromatic compounds found inhibitory or recalcitrant to biological treatments, were chosen as model chemicals for this study on the integration of photocatalytic-biological treatments. The degradation of each of these compounds was achieved by ultraviolet photocatalytic oxidation, leading to the formation of intermediate compounds. The photocatalytic treatment was performed in a TiO2 slurry reactor containing an aqueous solution of one of the three chemicals. The biodegradability of model wastewater treated photocatalytically was measured in terms of BOD1/TOC. Intermediate compounds that appeared at early stages of the photocatalytic degradation of m-dinitrobenzene or diphenylamine seemed to be more inhibitory than the parent compounds but this was not the case for resorcinol. A substantial improvement in BOD1/TOC could be achieved, but it required the mineralization of at least 80% of the organic carbon originally in the water. Microtox toxicity results confirmed the BOD1/TOC trends for diphenylamine.

Biodegradation, Environmental↗

Biodegradation of formaldehyde and its derivatives in industrial wastewater with methylotrophic yeast Hansenula polymorpha and with the yeast-bioaugmented activated sludge.

Methylotrophic yeast Hansenula polymorpha were shown to cooperate with activated sludge from biological wastewater treatment stations, enhancing substantially its potential to biodegrade formaldehyde in industrial wastewater. After integration with yeast cells the modified sludge retained its original structure and activity whereas its resistance to elevated formaldehyde concentrations was significantly improved. The applicability of the yeast in the utilization of formaldehyde derivatives, as exemplified by urotropine and trioxane, was also investigated. The treatment of urotropine-containing wastewater with methylotrophic yeast was found to be effective at acidic conditions (pH below 5.5). Trioxane was not degraded due to the stability of an ether bond which made themolecule recalcitrant to oxidation via methylotrophic pathway reactions. It is concluded that the yeast species may be applied to treat wastewater containing formaldehyde and some of its derivatives as either monocultures or as an integrated, specialized element of the activated sludge biocenosis.

Biodegradation, Environmental↗

Evaluation of coastal waters receiving fish processing waste: Lota Bay as a case study.

Liquid wastes from the fish meal and oil processing industries produce serious environmental impacts in coastal embayments on the coasts of Chile and Peru. This article presents an analysis of an environmental monitoring program at Lota Bay, a shallow coastal indentation in central Chile (37 degrees S) exposed to industrial fishing activity. The study of the environmental impact produced by waste effluents permitted making an evaluation of the bay's capacity for seasonal recovery from this impact. Seasonal cruises were carried out during 1994 and in 1996, 1997, and 1998. Variables analyzed included salinity, temperature, dissolved oxygen, ammonium concentration and surface oil and grease. The hydrographic regime of Lota Bay follows a seasonal pattern, where, typical of most SE pacific embayments, waters from subsuperficial oxygen minimum zones moved into the bay. The percentages of dissolved oxygen were critical in the area of organic waste discharge. The impact of wastewater is related to the type and status of the fishery, including: (i) overloads of plant production lines, (ii) maintenance and cleaning of installations, and (iii) degree of shipboard fishing conservation. Major alterations were observed in summer, when the highest discharge of organic load occurred. In winter, an improvement in the re-aeration conditions reduced the impact. Remedial measures implemented beginning in 1997 arose from the monitoring program and had to be separated into two recovery factors including (a) internal management of plants and (b) treatment of plant effluents.

Animals↗

A thromboxane effect of a hydroxytyrosol-rich olive oil wastewater extract in patients with uncomplicated type I diabetes.

OBJECTIVE: To assess the antioxidant/non-antioxidant effects of a hydroxytyrosol (HT)-rich phenolic extract from olive mill wastewaters administered with a breakfast. DESIGN, SETTING AND SUBJECTS: Five type I diabetic patients received 25 mg of HT the first day and 12.5 mg/day the following 3 days. Blood sampling was carried out at T(0) (baseline) and T(4d) just before the breakfast + HT administration and at time points 1, 2, 3 and 4 h after T(0). Urines (24-h) were collected from T(0) to T(4d). Baseline HbA1c was generally inferior to 10%, glycemia was within the range 6-24 mmol/l, whereas total cholesterol, HDL-chol and triglycerides were normal. RESULTS: The major finding was the 46% decrease in the serum TXB(2) production after blood clotting at T(4d). Plasma vitamin A, E, beta-carotene were not changed. Vitamin C tended to increase (P = 0.075). Plasma antioxidant capacity was enhanced at T(0)+1 h only, whereas its main determinants (albumin, bilirubin, uric acid) were not modified. Urinary 8-isoPGF(2alpha) levels were highly variable and were not affected significantly by HT administration. CONCLUSION: The major effect of HT accounts for an antiaggregating platelet action, leading to a possible prevention of thrombotic and microthrombotic processes.

Adult↗

Household hazardous waste in Massachusetts.

Household wastes, when disposed of improperly, are hazardous to health. This paper reports a random digit dial telephone survey of Massachusetts households concerning household hazardous waste (HHW) disposal with a 54% response. Of the automotive oil disposed of by 33% of survey households, 57% was deposited in the ground, sewer, or landfill. Annually by household oil disposal in Massachusetts is estimated to be 8.8 million quarts. Four percent of hazardous waste generated in Massachusetts is from households. Improper disposal makes it a major environmental contaminant. More households (41.5%) in smaller communities disposed of oil compared with 26% of households in larger communities. Paint and pesticides were disposed of by 10% of the households, but were dumped on the ground sewer or landfills more than 90% of the time.

Household Products↗

Fate of phosphorus from biological aerobic treatment of pig slurry. By-products characterization and recovery.

The fate of phosphorus distribution in the products obtained from biological aerobic treatment of pig slurry, e.g. separated solids, liquid effluent and sludge, was monitored in three different farm-scale units. Samples of raw slurry, solid products, aerated slurry, liquid effluent and sludge were characterised and analysed for their concentration in total phosphorus, nitrogen content and heavy metals (Cu and Zn). At each treatment stage, nitrogen, phosphorus and heavy metals mass balance between input and output was established. Moreover, liquid products were characterised and analysed both for their total and dissolved ortho-phosphate content. Separated solids, sludge and liquid effluent represented 5%, 15-40% and 75-83% of the mass of the raw slurry, respectively. A mechanical separation step prior to aeration allowed the export of 25-30% of total phosphorus for further use as organic fertiliser. A large amount of total phosphorus (e.g. 60-70%) was located in sludge while phosphorus remaining in liquid effluent was about 15-25%. Raw slurry separation and sufficient aeration allowed phosphorus to concentrate in the sludge. Insufficient aeration resulted in the release of phosphorus as dissolved ortho-phosphate within the liquid effluent. Finally, relevance of the agronomic use of the products was discussed and improvements of biological aerobic treatment to enhance phosphorus removal and/or recovery were considered.

Aerobiosis↗

Water resources management in soft drink industry-water use and wastewater generation.

Water is used in most process industries for a wide range of applications. Processes and systems using water today are being subjected to increasingly stringent environmental regulations on effluents and there is growing demand for fresh water. These changes have increased the need for better water management and wastewater minimisation. In Morocco, water use in the food and drink industry is extensive at approximately 24 million m3 per year including 14% of drinking water in 1994. This study was conducted in a carbonate soft drink industry plant, during two years, 2001 and 2002. We have investigated the state of consumption and use of fresh water and the generation of the effluent in the factory. The aim of the study is to identify potential opportunities for reducing fresh water intake and minimising wastewater production by studying the posibility of reuse, recycling and treatment.

Conservation of Natural Resources↗

Simulation of pulp mill wastewater recycling after tertiary treatment.

The aim of this work is to study the possibilities of effluent recycling in a bleached Kraft pulp mill, for a better water management. To avoid problems associated with effluent recycling (corrosion, odors, loss in pulp and paper quality), wastewaters have to be treated before recycling. This study is particularly focused on organic matter removal. Several treatments are applied on a biological secondary effluent: adsorption on activated carbon, coagulation with ferric chloride or alum sulfate, precipitation with lime, ozonation and catalytic ozonation. These techniques are compared in terms of COD (Chemical Oxygen Demand) removal. Catalytic ozonation is finally chosen as the most effective solution to achieve 50% of COD removal in the effluent. The characteristics of the effluent treated according to this technique are then used to simulate the impact of its reuse in the process for pulp production. The study is focused on the changes in these parameters in the various stages of bleaching and final washing when water is replaced by the wastewater treated or directly issued from the wastewater treatment plant. The simulation demonstrates the need of a tertiary treatment to eliminate COD in order to avoid possible reactant overconsumption and decrease in pulp brightness. Chloride and sulfate ions which could cause corrosion should also be removed.

Alum Compounds↗

Treatment of petrochemical wastewater by rotating biological contactor.

A laboratory scale study has been conducted to assess the efficiency of rotating biological contactor (RBC) to treat the synthetic wastewater from a petrochemical industry producing acrylonitrile. The attached biomass was acclimatised by gradually increasing cyanide concentration from 5 to 40 mg l(-1) with simultaneous increase in the concentration of chemical oxygen demand (COD) and ammonium nitrogen (NH4+-N). During acclimatization COD removal varied between 80-88 percent (%) while cyanide removal was more than 99%. The RBC was operated at varying hydraulic loading rates from 0.011 to 0.027 m3 m(-2) d(-1). The performance of the RBC was monitored for various parameters like COD, 5-day biochemical oxygen demand at 20-degree centigrade (degrees C) [BOD5], cyanide, ammonium nitrogen etc., for all hydraulic loadings. At all hydraulic loadings the cyanide removal remained more than 99%. The removals obtained in terms of percentage, for cyanide, COD, BOD5 and NH4+-N were greater than (>) 99, 95.2, 99.1 and 77, respectively at hydraulic loading of 0.011 m3 m(-2) d(-1). The effect of substrate/cyanide ratio on the performance of the process at five different ratios, 100/1, 80/1, 60/1, 40/1 and 20/1, showed more than 99% cyanide removal at ratio 20/1. The effect of COD/nitrogen (N) ratio was studied at four different ratios, 12/1, 10/1, 8/1 and 6/1, showed cyanide removal remained unaffected. The variation of biomass concentration within the system was also studied.

Bioreactors↗

Current strategies for dairy waste management: a review.

Industrial waste management is nowadays one of the main issues for ensuring a sustainable environment. Dairy waste management in particular, is very crucial in view of the high organic matter and high nutrient levels contained in dairy effluents. Dairy waste can be effectively treated either with aerobic or anaerobic processes. The main advantages of the former consist of low yield, high kinetics, pathogen free product, and high temperature operation whereas the latter is a simple, low budget and conservative technology. Occasionally, pre-treatment strategies (i.e. wetlands) are required in order to improve the efficiency of treatment methodology. Wetlands are a promising technology applied in order to remove the greater part of nutrients and minerals contained in milk based products.

Aerobiosis↗

Effluent management for a metal finishing industry aiming zero discharge conditions.

Technical applicability of zero discharge conditions is evaluated for the specific case of a large metal finishing industry located within the protection zone of a surface water body designated as a potential source for domestic water supply. Within the context of a sound water management strategy, a detailed process profile of the plant is established with relevant balance between water demand and wastewater generation. Quality restrictions for various water uses are identified. Wastewater flows are segregated depending on significant quality parameters. A comprehensive treatment scheme is defined for optimum wastewater recycle and reuse. Source allocation is made for the reuse of different streams of recycled wastewater. The study indicates that wastewater reuse can only be implemented with an efficiency of around 85-90% for the selected industry.

Chemical Industry↗

Coagulation-flocculation of wastewaters from a water-based paint and allied products industry and its effect on inert COD.

In this study, treatability of wastewaters generated from a water-based paint and allied products industry has been investigated. As the industry already houses a treatment facility that consists of a coagulation-flocculation unit followed by an activated sludge process, the experimental study focuses on using the existing treatment plant in the most efficient way. In this context the COD removal efficiencies and operating costs of different coagulants i.e., sodium bentonite, alum, FeCl(3) and FeSO(4) have been evaluated. By assessing the refractory COD content of the subsequent activated sludge system outlet, the coagulant yielding the optimal output has been addressed. The outcomes reveal that the optimum result can be obtained by applying 50 mg L(-1) of FeCl(3) coagulant at the original pH of the effluent.

Alum Compounds↗

A comparison of swine wastewater treatment using real-time and fixed-time two-stage sequencing batch reactors.

This study compared the swine wastewater treatment of two identical lab-scale two-stage sequencing batch reactors (TSSBR) under similar conditions except that one was operated on a fixed-time mode and the other on a real-time mode. While both TSSBR systems performed very well, the real-time TSSBR performed far better then the fixed-time TSSBR, in every aspect of carbon, nitrogen, and phosphorous removal. The removals of COD, TOC, were at 97% and for BOD5 even at 99.7%. In terms of NH4-N and TKN removals, the real-time TSSBR achieved removal of over 98%. For phosphorus removals (Ortho-P and total P) the results from the real-time TSSBR was quite remarkable at 97.7%.

Ammonia↗

Glycogen-accumulating organisms in laboratory-scale and full-scale wastewater treatment processes.

Laboratory-scale sequencing batch reactors (SBRs) as models for wastewater treatment processes were used to identify glycogen-accumulating organisms (GAOs), which are thought to be responsible for the deterioration of enhanced biological phosphorus removal (EBPR). The SBRs (called Q and T), operated under alternating anaerobic-aerobic conditions typical for EBPR, generated mixed microbial communities (sludges) demonstrating the GAO phenotype. Intracellular glycogen and poly-beta-hydroxyalkanoate (PHA) transformations typical of efficient EBPR occurred but polyphosphate was not bioaccumulated and the sludges contained 1.8% P (sludge Q) and 1.5% P (sludge T). 16S rDNA clone libraries were prepared from DNA extracted from the Q and T sludges. Clone inserts were grouped into operational taxonomic units (OTUs) by restriction fragment length polymorphism banding profiles. OTU representatives were sequenced and phylogenetically analysed. The Q sludge library comprised four OTUs and all six determined sequences were 99.7% identical, forming a cluster in the gamma-Proteobacteria radiation. The T sludge library comprised eight OTUs and the majority of clones were Acidobacteria subphylum 4 (49% of the library) and candidate phylum OP10 (39% of the library). One OTU (two clones, of which one was sequenced) was in the gamma-Proteobacteria radiation with 95% sequence identity to the Q sludge clones. Oligonucleotide probes (called GAOQ431 and GAOQ989) were designed from the gamma-Proteobacteria clone sequences for use in fluorescence in situ hybridization (FISH); 92% of the Q sludge bacteria and 28% of the T sludge bacteria bound these probes in FISH. FISH and post-FISH chemical staining for PHA were used to determine that bacteria from a novel gamma-Proteobacteria cluster were phenotypically GAOs in one laboratory-scale SBR and two full-scale wastewater treatment plants. It is suggested that the GAOs from the novel cluster in the gamma-Proteobacteria radiation be named 'Candidatus Competibacter phosphatis'.

Bacteria↗

Diversity of the archaeal community in 44 anaerobic digesters as determined by single strand conformation polymorphism analysis and 16S rDNA sequencing.

The diversity of Archaea in anaerobic digesters was characterized by strand conformation polymorphism (SSCP) analysis and the sequencing of 16S rDNA genes. The 44 digesters sampled, located in eight different countries, treated effluents from agriculture, the food processing and petro-chemical industries, pulp and paper plant, breweries, slaughterhouses and municipal waste. All the existing processes were represented among the samples (fixed-film, fluidized bed, stirred-tank, UASB, sequential batch reactor, lagoon). Single strand conformation polymorphism analysis targeting the V3 region of 16S rDNA revealed between four to six distinct archaeal peaks per digester. The diversity of dominant Archaea in the 44 digesters was estimated as 23 different 16S rDNA sequences. Cloning of archaeal 16S rRNA genes from 11 distinct total genomic DNA, screening of clones by SSCP and the sequencing of 170 of them made it possible to characterize these SSCP peaks. All the sequences retrieved were members of the Euryarchaeaota subdomain. Furthermore, most of the sequences retrieved were very close to already known and cultivated strains or to environmental clones. The most frequent archaeal sequences were close to Methanosaeta concilii and to a 16S rDNA clone vadinDC06 located in the Methanobacterium clade (84% and 73% of digesters respectively). The other sequences were members of the Methanobacteriales and the Methanomicrobiales families. Only one sequence was far from any sequence of the database and it could be grouped with several sequences of environmental clones. Each digester harboured between two to nine archaeal sequences with only one of them corresponding to a putative acetate-utilizing species. Furthermore, the process in the digesters appeared to play a part in the distribution of archaeal diversity.

Acetates↗