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PubMed2002

Importance of public relations in recycling strategies: principles and case studies.

The separate collection of waste, and especially of recyclables with specific collection systems, would not be possible without the involvement of the users. Apart from the physical installations such as collection containers, collection points, etc., the motivation of the users is an essential component. Motivation can be reinforced through public relations work. In addition to the underlying technical considerations, this paper describes the difference between communication in general and public relations and specifically examines public involvement in recycling. Through the use of examples, we look at the targeted users and typical media employed. Furthermore, we analyzes the development of public involvement. The examples show that public relations for recycling strategies relies to a great extent on attitudes, habits, and access to the target group. Thus, standardized procedures cannot be developed. For these reasons, public relation activities must be planned carefully and professionally and include an analysis of the target group, choice of media, and verification of success.

Communication↗
PubMed2004

Low pH as an inhibiting factor in the transition from mesophilic to thermophilic phase in composting.

During composting of household waste, the acidity of the material affects the process during the initial phase of rising temperature. In this study, the effects of temperature (36-46 degrees C) and pH (4.6-9.2) on the respiration rate during the early phase of composting were investigated in two different composts. A respiration method where small compost samples were incubated at constant temperature was used. The respiration rate was strongly reduced at 46 degrees C and pH below 6, compared to composts with a higher pH or lower temperature. The combination of high temperature and low pH is a possible adverse factor in large-scale composting of food waste.

Analysis of Variance↗
PubMed2005

Removal of volatile fatty acids with immobilized Rhodococcus sp. B261.

The removal of aqueous volatile fatty acids (VFA) in wastewater and spoiled waste-foods by immobilized Rhodococcus sp. B261 was investigated. The n-valeric acid (0.5%) was completely removed within 25 h under the following conditions; solution pH, 8.0; air flow rate, 0.2 l/min; superficial velocity, 0.96 h(-1); temperature, 37 degrees C. Under the optimized conditions, the acetic (8525 ppm), propionic (7310 ppm) and n-butyric (4360 ppm) except n-valeric (2572 ppm) acids from the wastewater were completely removed by immobilized Rhodococcus sp. B261 in 24 h. The acetic (7810 ppm), propionic (8942 ppm) and butyric (5730 ppm) acids from the solution of spoiled waste-foods were effectively removed by immobilized Rhodococcus sp. B261 from 48 h within 60 h but n-valeric acid (3625 ppm) took 72 h.

Acetic Acid↗
PubMed2005

Hydrolysis rates, methane production and nitrogen solubilisation of grey waste components during anaerobic degradation.

Municipal grey waste (i.e. the remaining fraction in municipal waste management systems in which putrescibles (biowaste) and other recyclables (paper, metals, glass) are source-segregated) was manually sorted into six main fractions on the basis of composition and also separated by sieving (100 mm mesh size) into two fractions, oversized and undersized, respectively. In practice, in waste management plant the oversized fraction is (or will be) used to produce refuse-derived fuel and the undersized landfilled after biological stabilisation. The methane yields and nitrogen solubilisation of the grey waste and the different fractions (all studied samples were first milled to 5 mm particle samples) were determined in a 237-day methane production batch assay and in a water elution test, respectively. The grey waste was found to contained remnants of putrescibles and also a high amount of other biodegradable waste, including packaging, cartons and cardboard, newsprint, textiles and diapers. These waste fractions comprised 41%-w/w of the grey waste and produced 40-210 m3 methane (total solids (TS))(-1) and less than 0.01 g NH4-N kg TS(added)(-1) except diapers which produced 9.8 g NH4-N kg TS(added)(-1) in the batch assays. In the case of the two sieved fractions and on mass bases, most of the methane originated from the oversized fraction, whereas most of the NH4-N was solublised from the undersized fraction. The first-order kinetic model described rather well the degradation of each grey waste fraction and component, showing the different components to be in the range 0.021-0.058 d(-1), which was around one-sixth of the values reported for the source-segregated putrescible fraction of MSW.

Bacteria, Anaerobic↗
PubMed2006

Thermophilic composting of food waste.

A laboratory reactor was designed to study the effects of operating parameters (air suction rate, seeding and agitation) on the composting process of a synthetic food waste made of dog food. Experimental results showed that the synthetic food waste could be composted within 4 days and the final compost passed the maturity tests. In most cases except those with 32% of seeding, the process involved two major stages of composting. The two peak temperatures between 50 and 60 degrees C occurred at 8-12th hour and 50-65th hour, respectively. Operating parameters that converted the most volatile solids and carbons in the feedstock were as follows: 1.6 l air/kg dry solid-min of air suction rate, 32% of seeding and 50% of agitation time.

Bioreactors↗
PubMed2006

Use of respirometer in evaluation of process and toxicity of thermophilic anaerobic digestion for treating kitchen waste.

A thermophilic anaerobic digestion (TAnD, 55 degrees C) system was adopted to hydrolyze the kitchen waste for 3 days, which was then fermented for a hydraulic retention time (HRT) of 10 days. The TAnD system performed much better than a similar system without thermal pre-treatment. A bubble respirometer was employed to study the effects of thermal pre-treatment, which showed that pre-treatment at 60 degrees C yielded the highest Total COD (TCOD) removal efficiency (79.2%) after 300h reaction. Respirometer results also indicated that oil and grease (O and G) began to inhibit the TAnD system at a concentration of approximately 1000mg/L and the gas production was inhibited by 50% at a concentration of approximately 7500mg/L of sodium.

Anaerobiosis↗
PubMed2006

Anaerobic on-site treatment of kitchen waste in combination with black water in UASB-septic tanks at low temperatures.

Anaerobic on-site treatment of a mixture of black water and kitchen waste (BWKW) was studied using two-phased upflow anaerobic sludge blanket (UASB) septic tanks at the low temperatures of 20 and 10 degrees C. Black water (BW) was also treated alone as reference. The two-phased UASB-septic tanks removed over 95% of total suspended solids (TSS) and 90% of total chemical oxygen demand (COD(t)) from both BWKW (effluent COD(t) 171-199mg/l) and BW (effluent COD(t) 92-100mg/l). Also, little dissolved COD (COD(dis)) was left in the final effluents (BW 48-70mg/l; BWKW 110-113mg/l). Part of total nitrogen (N(tot)) was removed (BW 18% and BWKW 40%) and especially at 20 degrees C ammonification was efficient. A two-phased process was required to obtain the high removals with BWKW at 10 degrees C, while with BW a single-phased process may have sufficed even at 10 degrees C. BWKW also produced more methane than BW alone. Sludge in phases 1 of BW and BWKW treatment was not completely stabilised after 198d of operation.

Anaerobiosis↗
PubMed2005

XANES study of Cr sorbed by a kitchen waste compost from water.

A kitchen waste compost was used to sorb Cr for various times from water containing either Cr(NO3)3 or CrO3 in different concentrations. Scanning electron microscopy (SEM) results show that the composts have been partially oxidized by Cr(VI) during the sorption experiments. X-ray absorption near edge structure (XANES) simulation suggests that about 54.1-61.0% Cr sorbed on the compost is in form of organic Cr(III) through ionic exchange process with the rest being existent as Cr(NO3)3 in the Cr(III) sorption case; no Cr(OH)3 is observed or expected because the solution pH after sorption experiments is or= 5.94. Moreover, organic Cr(III) represents about 51.7-69.0% of the total sorbed Cr, and the rest (6.1-28.5%) is Cr(VI).

Adsorption↗
PubMed2006

Preparation and sorption properties of porous materials from refuse paper and plastic fuel (RPF).

Porous materials consisting of activated carbon and amorphous CaO-Al(2)O(3)-SiO(2) (CAS) compound were prepared from refuse paper and plastic fuel (RPF), (a mixture of old paper and plastic) by carbonizing and/or activating treatments. Samples formed by chemical activation using K(2)CO(3) showed a high specific surface area (S(BET)) of 1330 m(2)/g but a lower ash content due to being washed after activation. By contrast, samples prepared by physical activation using steam showed rather lower S(BET) (510 m(2)/g) due to higher ash contents. The physically activated samples showed much higher uptake properties for Ni(2+) (a representative heavy metal) and phosphate ions (a representative of a harmful oxyanion) than the chemically activated samples because of the higher content of amorphous CAS in the former samples. By contrast, the chemically activated samples showed higher uptake for methylene blue (MB, a representative organic material) than the physically activated samples because of the higher activated carbon content of higher surface area. Although differences in the sorption properties for Ni(2+), phosphate ion and MB were found between the physically and chemically activated samples, both samples show excellent multiple sorption properties for cation-anion combinations and inorganic-organic sorbents.

Adhesives↗
PubMed2006

Adsorption of phenolic compound by aged-refuse.

The adsorption of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol by aged-refuse has been studied. Adsorption isotherms have been determined for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol and the data fits well to the Freundlich equation. The chlorinated phenols are absorbed more strongly than the phenol and the adsorption capacity has an oblivious relationship with the numbers and the position of chlorine subsistent. The experiment data suggests that both the partition function and the chemical adsorption involve in the adsorption process. Pseudo-first-order and pseudo-second-order model were applied to investigate the kinetics of the adsorption and the results show that it fit the pseudo-second-order model. More than one step involves in the adsorption process and the overall rate of the adsorption process appears to be controlled by the chemical reaction. The thermodynamic analysis indicates that the adsorption is spontaneous and endothermic.

Adsorption↗
PubMed2004

Entanglement of Australian sea lions and New Zealand fur seals in lost fishing gear and other marine debris before and after Government and industry attempts to reduce the problem.

In recent years, Australian governments and fishing industry associations have developed guiding principles aimed at reducing the impact of fishing on non-target species and the benthos and increasing community awareness of their efforts. To determine whether they reduced seal entanglement in lost fishing gear and other marine debris, we analysed Australian sea lion and New Zealand fur seal entanglement data collected from Kangaroo Island, South Australia. Contrary to our expectations, we found that entanglement rates did not decrease in recent years. The Australian sea lion entanglement rate (1.3% in 2002) and the New Zealand fur seal entanglement rate (0.9% in 2002) are the third and fourth highest reported for any seal species. Australian sea lions were most frequently entangled in monofilament gillnet that most likely originated from the shark fishery, which operates in the region where sea lions forage--south and east of Kangaroo Island. In contrast, New Zealand fur seals were most commonly entangled in loops of packing tape and trawl net fragments suspected to be from regional rock lobster and trawl fisheries. Based on recent entanglement studies, we estimate that 1478 seals die from entanglement each year in Australia. We discuss remedies such as education programs and government incentives that may reduce entanglements.

Animals↗
PubMed2004

Event mean concentration and loading of litter from highways during storms.

Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over 2 years. Gross pollutants were defined as larger than 0.5 cm and were classified into three categories. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. Event mean concentrations and mass emission rates are presented. No statistically significant correlations of litter production were noted, although the event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. The mass emission rates will be useful to estimate total litter production for developing total maximum daily loads.

California↗
PubMed2005

Use of starch and potato peel waste for perchlorate bioreduction in water.

The cost of carbon substrates for microbial reduction of perchlorate (ClO(4)(-)) is central to the success and competitiveness of a sustainable bioremediation strategy for ClO(4)(-). This study explored the potential application of starch in combination with an amylolytic bacterial consortia and potato peel waste for ClO(4)(-) bioreduction. We obtained a potent amylolytic bacterial consortium that consisted of a Citrobacter sp. S4, Streptomyces sp. S2, Flavobacterium sp. S6, Pseudoxanthomonas sp. S5, Streptomyces sp. S7, and an Aeromonas sp. S8 identified by 16S rDNA sequencing. ClO(4)(-) concentration substantially decreased in purified starch medium inoculated with the amylolytic bacterial consortium and Dechlorosoma sp. perclace. Potato peel waste supported ClO(4)(-) reduction by perclace with the rate of ClO(4)(-) reduction being dependent on the amount of potato peels. Over 90% ClO(4)(-) removal was achieved in 4 days in a single time point experiment with 2% (w/v) potato peels waste. ClO(4)(-) reduction in a non-sterile 0.5% potato peel media inoculated with perclace occurred with an initial concentration of 10.14+/-0.04 mg L(-1) to 2.87+/-0.4 mg L(-1) (71.7% reduction) within 5 days. ClO(4)(-) was not detected in the cultures in 6 days. In a non-sterile 0.5% potato media without perclace, ClO(4)(-) depletion occurred slowly from an initial value of 9.99+/-0.15 mg L(-1) to 6.33+/-0.43 mg L(-1) (36.63% reduction) in 5 days. Thereafter, ClO(4)(-) was rapidly degraded achieving 77.1% reduction in 7 days and not detected in 9 days. No susbstantial reduction of ClO(4)(-) was observed in the sterile potato peel media without perclace in 7 days. Redox potential of the potato peel cultures was favorable for ClO(4)(-) reduction, decreasing to as low as -294 mV in 24 h. Sugar levels remained very low in cultures effectively reducing ClO(4)(-) and was substantially higher in sterilized controls. Our results indicate that potato peel waste in combination with amylolytic microorganisms and Dechlorosoma sp. perclace can be economically used to achieve complete ClO(4)(-) removal from water.

Bacteria↗
PubMed2006

Critical components of odors in evaluating the performance of food waste composting plants.

The current Taiwan government policy toward food waste management encourages composting for resource recovery. This study used olfactometry, gas chromatography-mass spectrometry (GC-MS) and gas detector tubes to evaluate the ambient air at three of the largest food waste composting plants in Taiwan. Ambient air inside the plants, at exhaust outlets and plant boundaries was examined to determine the comprehensive odor performance, critical components, and odor elimination efficiencies of various odor control engineering. Analytical results identified 29 compounds, including ammonia, amines, acetic acid, and multiple volatile organic compounds (VOCs) (hydrocarbons, ketones, esters, terpenes and S-compounds) in the odor from food waste composting plants. Concentrations of six components--ammonia, amines, dimethyl sulfide, acetic acid, ethyl benzene and p-Cymene--exceeded human olfactory thresholds. Ammonia, amines, dimethyl sulfide and acetic acid accounted for most odors compared to numerous VOCs. The results also show that the biotrickling filter was better at eliminating the concentrations of odor, NH(3), amines, S-compounds and VOCs than the chemical scrubber and biofilters. All levels measured by olfactometry at the boundaries of food waste composting plants (range, 74-115 Odor Concentration (OC)) exceeded Taiwan's EPA standard of 50 OC. This study indicated that the malodor problem continued to be a significant problem for food waste recovery.

Air Pollutants↗
PubMed2005

Time-course changes of mixture effects on AhR binding-dependent luciferase activity in a crude extract from a compost sample.

Crude extracts of environmental samples contain stable and labile aryl hydrocarbon receptor (AhR) ligands, and show huge activities in the cell-based bioassay, and these activities are higher than the chemically calculated induction equivalent values. It is thought that not only unidentified AhR ligands but also mixture effect among compounds might contribute to these activities. In the previous work, we have indicated that hydrophobic compounds in household sewage sludge (HSS) compost may interact synergistically with 2,3,7,8-TCDD in the CALUX (DR-CALUX: Dioxin-Responsive Chemical-Activated Luciferase gene eXpression) assay [Suzuki, G., Takigami, H., Kushi, Y., Sakai, S., 2004. Evaluation of mixture effects in a crude extract of compost using the CALUX bioassay and HPLC fractionation. Environ. Int. 30, 1055-1066]. In this study, we focused on co-existing stable compounds such as halogenated aromatic hydrocarbons (HAHs) and labile compounds such as polyaromatic hydrocarbons (PAHs) in the crude extract and investigated the time-course changes of mixture effects among compounds in environmental samples using the CALUX assay and normal-phase high-performance liquid chromatography (NP-HPLC) fractionation. We confirmed that CYP1A-inducing PAHs and HAHs could be separated by NP-HPLC on a nitrophenylpropylsilica (NITRO) column. To determine whether the activities of AhR ligands in environmental samples (including the HSS compost) could be assessed by the additivity theory, we compared the CALUX activity of the crude extract with the arithmetical sum of the activities of all the fractions separated by NP-HPLC. We confirmed a potentiation of CALUX activity at 12-, 24- and 48-h exposure durations. In contrast, CALUX activity increased additively at 6- and 72-h exposure durations. CALUX activity was potentiated when the CALUX activity of the HPLC fractions showed a remarkable reduction resulting in a change of activity profiles. In contrast, additivity was observed at a 72-h exposure duration when the CALUX activity of the HPLC fractions showed neither remarkable reduction nor a change in profile. Our results suggest that differences in the metabolic decomposition of compounds affected mixture effects on CALUX activity in a crude extract from HSS compost.

Animals↗
PubMed2004

Stochastic modelling of landfill leachate and biogas production incorporating waste heterogeneity. Model formulation and uncertainty analysis.

A mathematical model simulating the hydrological and biochemical processes occurring in landfilled waste is presented and demonstrated. The model combines biochemical and hydrological models into an integrated representation of the landfill environment. Waste decomposition is modelled using traditional biochemical waste decomposition pathways combined with a simplified methodology for representing the rate of decomposition. Water flow through the waste is represented using a statistical velocity model capable of representing the effects of waste heterogeneity on leachate flow through the waste. Given the limitations in data capture from landfill sites, significant emphasis is placed on improving parameter identification and reducing parameter requirements. A sensitivity analysis is performed, highlighting the model's response to changes in input variables. A model test run is also presented, demonstrating the model capabilities. A parameter perturbation model sensitivity analysis was also performed. This has been able to show that although the model is sensitive to certain key parameters, its overall intuitive response provides a good basis for making reasonable predictions of the future state of the landfill system. Finally, due to the high uncertainty associated with landfill data, a tool for handling input data uncertainty is incorporated in the model's structure. It is concluded that the model can be used as a reasonable tool for modelling landfill processes and that further work should be undertaken to assess the model's performance.

Biodegradation, Environmental↗
PubMed2004

Immobilization of lead and zinc in scrubber residues from MSW combustion using soluble phosphates.

The immobilization of MSWI-scrubber residues with soluble PO4(3-) was studied and compared to the immobilization using cement. The DIN 38414-S4 leaching protocol and pH dependent leaching were used to evaluate the leaching of Pb and Zn. Four different scrubber residues from MSW combustion (Pb concentration: 2.8-4.8 mg/g; Zn concentration: 3.0-12.3 mg/g) were mixed with water and cement or Na2HPO4 as source of soluble PO4(3-) at dosages of at least 0, 0.1, 0.2, 0.3 and 0.4 g per g residue. With cement as well as with PO4(3-) a reduction in Pb and Zn leaching was observed. With 0.4 g cement per g residue, the Pb leaching was reduced by a factor ranging from 70 to 100, but still exceeded the Pb landfill limit of 2 mg/l. With PO4(3-) the Pb leaching was reduced with a factor of 100-300 to below 2 mg/l. The Zn landfill limit (10 mg/l) was only exceeded by one untreated residue. Adding 0.2 g cement or 0.1 g PO4(3-) per g of that residue was enough to reduce leaching below 10 mg/l. However, when 0.6 g Na2HPO4 per g residue was added to a lime based scrubber residue, an increase in Zn leaching up to 12.5 mg/l was observed due to an increase in pH of up to 13.0. When using NaH2PO4 and H3PO4 no such increase in Zn leaching was observed. pH dependent leaching performed on one of the four residues showed that in the pH range of 2.5-6, Pb leaching was 100-50 times lower with Na2HPO4 treatment than with cement. In the pH range from 7-11, almost equal results were obtained for cement treated and Na2HPO4 treated residue. Above a pH of 12, Pb leaching was three times lower for the PO(4)(3-)-treated residue than for the cement treated residue. With soluble PO4(3-), Pb leaching below 2 mg/l could be attained at a dosage of 0.27 g PO4(3-)/g residue. With cement, Pb leaching was never below 2 mg/l.

Belgium↗