High Density Polyethylene Containers Research Articles

Comparison of multiple preservation and digestion methods for determination of tungsten concentrations in environmental media using ICP-MS

Tungsten is an emerging environmental pollutant. However, a proved robust method for preserving and determining the concentrations of tungsten in environmental media is still lacking. This study examined and compared the suitability of classic methods and previously reported tungsten-oriented methods on preserving dissolved tungsten and recovering tungsten from soil/sediment matrix. Tungsten concentrations in the water samples and digestates were then determined by inductively coupled plasma mass spectrometry. Our data showed that the tungsten-oriented HF and alkaline preservatives indeed successfully maintained the stability of dissolved tungsten. Even when preserved using HNO3 or HCl, dissolved tungsten concentrations did not notably change in most of our water samples over the course of ∼4 months. Using glass containers for storing water samples also did not produce much difference from using high-density polyethylene containers. Our data further suggested that the addition of HF in digestion was important for tungsten solubilization from soil/sediment matrix. The digestion methods with HNO3/HCl/HF and HNO3/HF/NH4OH/EDTA both yielded quantitative recoveries of tungsten from certified reference materials and known synthetic samples, while the other tested methods had limited recoveries. The methods validated by this study could be used to accurately determine tungsten concentrations in environmental media and thereby to assess the fate and potential risks of tungsten.

Assessment of perfluorocarboxylic acids in fluorinated high-density polyethylene containers and estimation of potential non-cancer risks associated with anticipated use scenarios

High density polyethylene (HDPE) containers are fluorinated to impart barrier properties that prevent permeation of liquid products filled in the container. The process of fluorination may result in the unintentional formation of certain per- and polyfluoroalkyl substances (PFAS), specifically perfluoroalkyl carboxylic acids (PFCAs), as impurities. This study measured the amounts of PFCAs that may be present in the fluorinated HDPE containers, which could migrate into products stored in these containers. Migration studies were also conducted using water and mineral spirits to estimate the amount of PFCAs that might be found in the products stored in these containers. The migration results were used to conservatively model potential PFCA exposures from use of six product types: indoor-sprayed products, floor products, hand-applied products, manually-sprayed pesticides, hose-end sprayed products, and agricultural (industrial) pesticides. The potential that such uses could result in a non-cancer hazard was assessed by comparing the modeled exposures to both applicable human non-cancer toxicity values and environmental screening levels. Environmental releases were also compared to aquatic and terrestrial predicted no-effect concentrations (PNECs). The results of these analyses indicated no unreasonable non-cancer risk to humans, aquatic species, and terrestrial species from PFCAs in products stored in fluorinated HDPE containers.

Assessment of risk factors of food safety in local butter marketing in Kersa, Mana and Welmera districts of Oromia, Ethiopia

Risk factors pre-disposing local butter to food safety hazards in the informal marketing system along the supply chain of the central highlands and south-west midlands of Ethiopia were assessed. Purposive random sampling technique was used to select 1101 respondents from the local butter supply chain (532 producers, 107 retailers and 462 consumers). Data were collected using a semi-structured questionnaire developed separately for each category of respondents. Ninety- nine percent of the respondents indicated that butter was stored and marketed at ambient temperature with no cold chain management. Common butter storage materials included high-density polyethylene containers (51%), low-density polyethylene plastic bags (29%) and clay pots (73%). The respondents packed and marketed butter using castor leaves, plastic cups and false banana leaves and lints. Stream, river and borehole water sources were used to wash vessels, churners and fresh butter. However, only 23% of the respondents used tap water for the same purposes. The majority of the respondents trekked on their foot to take butter to local market places followed by the use of horse carts (11%) and three-wheel drives (10%). Itinerant traders and retailers played key roles in the informal supply chain of butter. Overall, there are no standard operating procedures and infrastructures along the supply chain. Thus, local butter supplied to consumers is liable to sensorial, physico-chemical and microbial deterioration and is exposed to risks of food-borne pathogens. The practices endanger the safety and quality of local butter unless stringent quality control measures are taken by concerned regulatory bodies. The objective of the study was to identify risk factors and design intervention to minimize the food safety hazards in butter. Key words: Food safety hazards, informal market, local butter, risk factors, supply chain

An assessment of the potential for leaching of per- and polyfluoroalkyl substances from fluorinated and non-fluorinated high-density polyethylene containers

Per- and polyfluoroalkyl substances (PFAS) have garnered world-wide attention over the last two decades due to their extreme environmental persistence and potential adverse health effects. Research is ongoing as to where, and in what quantities, PFAS can be found in commercial, and consumer goods. During 2021, a study described detecting PFAS in a commercially available insecticide; however, further study clarified that the source of PFAS was not actually from the insecticide product, but rather the fluorinated high-density polyethylene (fHDPE) container in which the insecticide resided. As several fluorination technologies associated with fHDPE manufacturers are available, the work described herein was conducted to determine the potential leaching of PFAS from the various fluorinated container technologies. Three fluorination technology container types, including advanced in-mold fluorination, post-mold fluorination, and post-mold plasma fluorination; and two non-fluorinated negative control, were subject to extended methanol soaking periods. During these soak periods, aliquots of methanol were removed and analyzed for 19 target PFAS compounds. For the advanced in-mold fluorination technology, at each of the residence period, showed no detectable PFAS at the analytical instruments limit of quantification (LOQ) of 10 ng/L (20 ng/L for GenX). In contrast, several PFAS compounds were detected above LOQ in the alternative fluorination technologies, ranging from 11 - 9700 ng/L in methanol, throughout the entirety of the residence periods.

Evaluation of the damaging effect of crop protection formulations on high density polyethylene using the Full Notch Creep Test

Four typical high-density polyethylene container materials were used to investigate damage or stress cracking behavior in contact with model liquids for crop protection products. These model liquids are established in German regulations for the approval of dangerous goods containers and consist of typical admixtures used for crop protection products but without biological active ingredients. This study is performed with the standardized method of Full Notch Creep Test, adapting the media temperature to 40 °C according to the usual conditions where these test liquids are applied. The two model liquids differ into a water-based solution and a composition based on different organic solvents which are absorbed by the material up to significant levels. Therefore, extensive sorption measurements are performed. The fracture surfaces obtained are analyzed in detail not only by light microscopy, but also by laser scanning microscopy as well as scanning electron microscopy. Influence of pre-saturation and applied stress are addressed by respective systematic series of experiments.

Drying and packaging methods impact the bacoside profile and microbiological quality of Brahmi herb (Bacopa monnieri L.) during storage

Retention of quality in herbal drugs during drying and storage is of great concern and the information is lacking in an important memory enhancing medicinal herb Brahmi (Bacopa monnieri L.). This is the first ever report on effect of drying methods, packaging materials as well as storage duration on the bacoside A profile and microbiological quality. Freshly harvested herbage was dried with five different methods of drying viz., shade, sun, solar tunnel, cabinet, low cost polyhouse, followed by packing dried herbage for five months duration in different containers viz., polythene lined jute bags, woven polypropylene sacks, corrugated fiber board boxes, and 125 μm thick high density polyethylene containers. Drying of fresh herbage at 50 °C for 12 h in cabinet drier retained the highest bacoside A components compared with all other methods. Solar tunnel drying was the second best method, while conventional shade dried samples recorded lowest bacoside A level. Bacoside A profile in cabinet samples immediately after drying was 4.8 mg/g bacoside A3, 6.0 mg/g bacopaside II, 5.0 mg/g jujubogenin isomer of bacopasaponin C and 4.6 mg/g bacopasaponin C. Ambient temperature storage (23 ± 2 °C) for five months resulted in loss of bacoside A from the herbage; but packaging in high density polyethylene significantly reduced the loss compared with other packages irrespective of the drying methods. Cabinet dried samples stored in high density polyethylene packages for five months possessed 3.0 mg/g bacoside A3, 4.1 mg/g bacopaside II, 2.5 mg/g bacopasaponin C and 3.2 mg/g jujubogenin isomer of bacopasaponin C. The microbiological quality was also satisfactory during storage in high density polyethylene container. Thus, the work identified a protocol for hygienic way of drying and packaging of Brahmi to retain the bacosides during storage.

Photothermal Floats for Evaporation Enhancement and Waterfowl Deterrence

Many industries store hazardous liquid waste in open ponds prior to treatment or as a means of disposal. In some cases, these ponds may present a hazard to migrating waterfowl. Present methods of deterring birds, such as plastic ‘shade balls’, reduce evaporation, making them ineffective where evaporation is desirable. To combat this effect, we applied photothermal materials to high-density polyethylene (HDPE) containers to create “photothermal floats”, which absorb solar irradiation and promote, rather than deter, evaporation. In this study, inexpensive materials (granular activated carbon, fiberglass, and carbon air filters) were coated onto HDPE containers. Carbon foam, a buoyant material, was used alone. These materials were tested for their effects on evaporation rates in a laboratory environment at low light intensities (150 W∙m−2). Granular activated carbon (GAC) displayed the largest improvement in evaporative performance, increasing the evaporation rate by 64 ± 7% compared to a control with standing water and 199 ± 7% compared to uncoated HDPE. Materials were characterized using scanning electron microscopy, specific surface area analysis, water retention analysis, contact angle goniometry, and reflectance. We observed significant and unexpected differences between materials in all parameters and their connections to measured evaporation rates. These novel and inexpensive material combinations may provide a new tool for water managers who need to maintain or improve evaporation rates while deterring waterfowl.

Safety evaluation of different acids in high-density polyethylene container loading

To reduce costs, high-purity chemical suppliers wash and reuse HDPE containers collected from users. To determine the lifetime of a container, the appearance of that container and the manufacturer's recommendations for its lifetime are generally considered. Guidelines for determining the lifetime of an HDPE container have not been clearly defined. The lack of these specifications may result in the leakage of high-purity chemicals in the storage, transportation and use of HDPE containers. To understand the effects of using high-purity chemicals (sulfuric acid (H2SO4) and nitric acid (HNO3)) on HDPE, this study revealed its effects by mechanical and thermal performance tests. According to the mechanical properties test results, the ductility and tensile strength of HDPE soaked H2SO4 and HNO3 decreased. HDPE immersed in HNO3 exhibited the lowest thermal stability by thermal performance testing. In summary, the degradation of HDPE is affected by storage conditions. For this study, HDPE only needs 60 days of immersion in HNO3, and its ductility and tensile strength will decline obviously. This study shows that when these containers are used for long-term storage of high purity chemicals, the mechanical properties (including ductility, ductility, and tensile strength) of HDPE containers tend to decrease. To decrease accidental leakage of chemicals due to aging of HDPE, comprehensive and approved regulations should be established for the loading, transport, and storage of HDPE containers.

A high-density polyethylene container based on ZnO/lignin dual fillers with potential antimicrobial activity

Dual ZnO/lignin hybrid fillers were obtained and subjected to detailed physicochemical and morphological-microstructural analysis. The effectiveness of combination of the components was assessed using Fourier transform infrared spectroscopy. It was shown that the addition of zinc oxide improves the thermal stability of the final hybrid filler. A hybrid material consisting of ZnO and lignin in a weight ratio of 1:5 exhibited very good antimicrobial activity, especially against Gram-positive bacteria (in both of the tested genera: Staphylococcus and Bacillus). In all cases, the action of this material was stronger than that of the positive control, the antibiotic tetracycline. Blow-molded containers made of polyethylene containing 5 wt% of ZnO/lignin with different lignin contents were prepared with a single-screw extruder. The effect of ZnO/lignin hybrid fillers on the properties of a high-density polyethylene container was investigated by means of a uniaxial compression test. Mechanical tests demonstrated a significant twofold increase in the compression force for blends with a ZnO:lignin ratio of 1:5. Additionally, DSC analysis was performed to study the influence of the dual fillers on the microstructure of the blended polyethylene.

Storage evaluation of a functional food with skimmed milk enriched with fatty acids of Sacha Inchi (Plukenetia volubilis L.)

The aim of this study was obtain a semi skim milk enriched with sacha inchi oil (Plukenetia volubilis L.), with sensory acceptability and a suitable storage container. The raw materials used were: fresh semi skim milk of creole cow and virgin sacha inchi oil. The content of polyunsaturated fatty acids raised from 2.8% to 3.0; 3.2% and 3.4% according to the treatment. It was evaluated the sensory microbiological properties of the semi skim milk during its storage period of 30 days. The packaging material used were high density polyethylene container and glass container. The best formulation for semi skim milk was the correspond to 3% of fatty acids stored in glass container which obtained values of: Taste 2.2; Color 2.1; Texture 2.2 and Appearance 2.2 on a maximum of 5.0 units. It is concluded that the production of semi skim milk enriched with fatty acids of sacha inchi is feasible.

Fluorescence labeling of high density polyethylene for identification and separation of selected containers in plastics waste streams. Comparison of thermal and photochemical stability of different fluorescent tracers

In recent years, a great effort has been devoted to the development of new automated identification and sorting methods for post-consumer plastics in the waste streams that reach the recycling processes, as the final properties of the recycled materials largely depend on the purity of the plastic residue. This work explores the use of fluorescence spectroscopy as a complementary technique to address the limitations of the current technologies. Specifically, the use of fluorescent markers for the removing, for technical or safety related issues, of selected high density polyethylene containers from the waste stream has been studied. The results indicate that identification by extrinsic fluorescence can be easily achieved even with small proportion of markers (10−3wt%) without significant change of the polymer structure. The effect of thermal, hygrothermal and photochemical degradation on the fluorescence emission has been analyzed. Although the signal intensity decreases during the accelerated degradation, distinguishable fluorescent emission was recorded even after sample exposure to aggressive conditions, thus enabling the correct identification of the marked plastics.

The influence of ultra-pasteurization by indirect heating versus direct steam injection on skim and 2% fat milks

Fluid milk is traditionally pasteurized by high temperature, short time (HTST) pasteurization, which requires heating to at least 72°C for 15 s. Ultra-pasteurization (UP) extends milk shelf life and is defined as heating to at least 138°C for 2 s. The UP process can be done by indirect heating (IND) or by direct steam injection (DSI). The influence of these 2 UP methods on milk flavor has not been widely investigated. The objective of this study was to compare the effect of HTST, IND-UP, and DSI-UP on sensory perception of fluid milk. Raw skim and standardized 2% milks were pasteurized at 140°C for 2.3 s by IND or DSI or by HTST (78°C, 15 s) and homogenized at 20.7 MPa. The processed milks were stored in light-shielded opaque high-density polyethylene containers at 4°C and examined by descriptive analysis and microbial analysis on d 3, 7, and 14. Furosine and serum protein denaturation analyses were performed on d 0 and 14 as an indicator of heat treatment. Last, consumer acceptance testing was conducted at d 10, with adults (n = 250) and children (ages 8 to13 y, n = 100) who were self-reported consumers of skim or 2% milk; consumers only received samples for either skim or 2% milk. The entire experiment was repeated in triplicate. Milks treated by HTST had lower cooked flavor than either UP milk. Milks heated by DSI-UP were characterized by sulfur or eggy and cooked flavors, whereas IND-UP milks had higher sweet aromatic and sweet taste compared with DSI-UP milk. Aromatic flavor intensities of all milks decreased across 14 d of storage. Furosine concentrations and serum protein denaturation were highest for the IND treatments, followed by DSI and HTST. Furosine content in both skim and 2% milk increased with time, but the increase was faster in IND-UP skim milk. Adult and child consumers preferred HTST milk over either UP milk, regardless of fat content. Ultra-pasteurization by IND or DSI did not affect consumer acceptance at 10 d postprocessing, but traditional HTST milks were preferred by consumers of all ages.

Charging-discharging characteristics of macro-encapsulated phase change materials in an active thermal energy storage system for a solar drying kiln

The present study explores suitability of two phase change materials (PCM) for development of an active thermal storage system for a solar drying kiln by studying their melting and solidification behaviors. A double glass glazing prototype solar kiln was used in the study. The storage system consisted of a water storage tank with PCM placed inside the water in high density polyethylene containers. The water in the tank was heated with help of solar energy using an evacuated tube collector array. The melting and solidification temperature curves of PCM were obtained by charging and discharging the water tank. The study illustrated the utility of the PCM in using the stored thermal energy during their discharge to enhance the temperature inside the kiln. The rate of temperature reduction was found to be higher for paraffin wax as compared to a fatty acid based PCM. The water temperature during the discharge of the PCM showed dependence on the discharge characteristics of each PCM suggesting their suitability in designing active thermal storage systems.

Development of mango (Mangifera indica L.) energy drinks

The effect of two hydrocolloids, pectin and carboxymethyl cellulose (CMC), was evaluated in mango beverage stability (Mangifera indica L.) formulated and developed with caffeine at a concentration of 30 mg/100 mL. The physico-chemical and sensory characteristics of color, acidity, viscosity, total soluble solids, pH, flavor, aroma and texture were studied every three days over a 12-day period. The beverages were packaged in high-density polyethylene containers with a 250 mL capacity and were stored at 5 °C and 90% RH for the duration of the experimentation period. The drinks with added pectin showed greater stability and lower acidity values than the control, but higher values than those prepared with CMC. The drinks made with CMC had a significantly higher viscosity at a 95% confidence level than those made with pectin or the control beverages. The treatment that showed the lowest browning index was the one added with pectin. Concerning the sensory evaluation, the drinks showed significant differences at a 95% confidence level; the drink made with pectin was the most widely accepted. It was concluded that the most stable drinks were those made with pectin because they presented the lowest height in millimeters of precipitate solids over the storage period. No off-flavors in beverages were perceived by the judges.

Emissions from open burning of used agricultural pesticide containers

Emissions from simulated open burning of used agricultural pesticide containers were sampled for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), polycyclic aromatic hydrocarbon compounds (PAHs), and particle matter (PM10 and PM2.5). Clean high density polyethylene (HDPE) containers, containers with trace pesticide, and triple-rinsed containers were burned separately in an open combustion facility and their emissions compared. Two common chlorinated pesticides were used: 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine (atrazine). PCDD/PCDF emission factors ranged from 0.1 to 24ng toxic equivalents (TEQ)/kg C burned with a mean and median of 4.9 and 1.9ng TEQ/kgC burned, respectively. In a limited number of trials, the trace 2,4-D in the HDPE container led to a statistically significant increase in PCDD/PCDF formation compare to all other conditions. Residual atrazine did not lead to more PCDD/PCDF than the unrinsed 2,4-D container. Total (16 compounds) PAH emission factors varied from 1.5 to 6.7mg/kgC burned. These limited data suggest that rinsing the 2,4-D container prior to burning reduces both PCDD/PCDF and PAH emissions. Nine PM2.5 emission factors ranged from 9 to 35mg/gC burned and ten PM10 values ranged from 6 to 43mg/gC burned. Neither pesticide appeared to have any effect on PM concentration.

A study of techniques for the preservation of mercury and other trace elements in water for analysis by inductively coupled plasma mass spectrometry (ICP-MS)

The storage of aqueous solutions in high density polyethylene (HDPE) bottles containing nitric acid (0.15 to 2.0% (v/v) was shown to be unsuitable for the preservation of dissolved mercury (Hg2+) either as a single element or as part of a multi-element solution. At concentrations ranging from 0.05 to 10.0 ug l−1 more than 10% of the dissolved mercury was lost within the first three days and up to 50% of the mercury was lost within nine days after solutions were prepared. However mercury was stable in the presence of hydrochloric acid (HCl) or sodium chloride (NaCl). Solutions of either 40 mg l−1NaCl in 0.15% (v/v) nitric acid (HNO3) or 0.01% (v/v) HCl in 1% (v/v) HNO3 were found to be effective for preserving mercury for more than 50 days. The stabilising mechanism is most likely the formation of HgCl42− complex ions that prevent the adsorption of mercury on the inner walls of the HDPE container. The elements Al, Ag, As, Ba, B, Cd, Cr, Co, Cu, Mn, Mo, Ni, Pb, Sb, Se, Tl, V and Zn were stable up to 12 months when preserved in 1.0 to 2.0% (v/v) nitric acid or a mixture of 1% (v/v) HNO3 plus 0.01% (v/v) HCl. The recommended acid combination for the preservation of mercury and multi-elements for the simultaneous determination by ICP-MS is 1% (v/v) HNO3 plus 0.01% (v/v) HCl. Chloride related polyatomic interferences in ICP-MS determination from this acid mixture were less than 0.1 ugl−1 for all elements investigated, making it an ideal preservation medium for ICP-MS analysis.

Mesocosm trials of bioremediation of contaminated soil of a petroleum refinery: comparison of natural attenuation, biostimulation and bioaugmentation

Contamination with petroleum hydrocarbons (PHC) is a global problem with environmental implications. Physico-chemical treatments can be used for soil cleanup, but they are expensive, and can have implications for soil structure and environment. Otherwise, biological remediation treatments are cost-effective and restore soil structure. Several remediation experiments have been carried out in the lab and in the field; however, there is the challenge to achieve as good or better results in the field as in the laboratory. In the ambit of a project aiming at investigating suitable biological remediation approaches for recovering a refinery contaminated soil, we present here results obtained in bioremediation trials. The approaches biostimulation and bioaugmentation were tested, in parallel, and compared with natural attenuation. For this purpose, mesocosm experiments were carried out inside the refinery area, which constitutes a real asset of this work. Soil contaminated with crude oil was excavated, re-contaminated with turbine oil, homogenised and used to fill several 0.5 m(3) high-density polyethylene containers. The efficiency of procedures as follows: (1) natural attenuation; (2) manual aeration; (3) biostimulation by adding (3.1) only nutrients; and (3.2) nutrients and a non-ionic surfactant; and (4) bioaugmentation in the presence of added (4.1) nutrients or (4.2) nutrients and a non-ionic surfactant were evaluated after a 9-month period of experiment. For bioaugmentation, a commercial bacterial product was used. In addition to physico-chemical characterization, initial and final soil contents in total petroleum hydrocarbons (TPH) (by Fourier transform infrared spectrophotometry) and the total number of bacteria (by total cell counts) were carried out. For TPH degradation evaluation the soil was divided in four fractions corresponding to different depths: 0-5; 5-10; 10-15; and 15-20 cm. Mean values of percentages of PHC degradation varied between 20 and 50% at surface and between 10 and 35% below 5-cm depth. Natural attenuation was as efficient as most of the tested treatments (about 30% TPH degradation) being exceeded only by bioaugmentation combined with nutrient and surfactant amendments (about 50% TPH degradation). Higher TPH degradation at surface suggests that a combination of sufficient dioxygen, propitious for aerobically degradation, with sunlight required for production of strong photochemical oxidants like ozone, contributed for enhancing degradation. Indeed, the atmosphere of the refineries is relatively rich in volatile organic compounds and nitrogen dioxide (a side-product of the combustion of residual volatile PHC released by the chimneys), which are precursors of O(3) and other photochemical oxidants produced in sunny days, which are very common in Portugal. The fact that natural attenuation was as efficient as most of the soil treatments tested was very probably a result of the presence, in the initial soil, of physiologically adapted native microorganisms, which could be efficient in degrading PHC. A cost-effective way to reduce half-life for the degradation of PHC of contaminated soil of the refinery will be a periodic revolving of the soil, like tillage, in order to expose to the oxidative atmosphere the different layers of contaminated soil. A combination of soil revolving with bioaugmentation together with nutrients and surfactant amendments may result in an additional improvement of PHC degradation rate. However, this last procedure will raise markedly the price of the remediation treatment.

Comparative stability of repackaged metoprolol tartrate tablets

The stability of metoprolol tartrate tablets packaged in original high density polyethylene containers and repackaged in USP Class A unit-dose blister packs was investigated. Studies were conducted at 25 °C/60% relative humidity (RH) for 52 weeks and at 40 °C/75% RH for 13 weeks. The potency, dissolution, water content, loss on drying and hardness of the drug products were analyzed. Results indicated no differences in the stability between the tablets in both packages stored under 25 °C/60% RH. No difference in potency was found in both packages under either condition. However, a significant weight increase due to moisture uptake was observed for the repackaged tablets stored under 40 °C/75% RH. The weight increase was accompanied by a decrease in tablet hardness (6.5–0 kp) and a increase in dissolution rate (51–92%) in 5 min. Near-infrared (NIR) chemical imaging also monitored moisture uptake of the tablet non-invasively through the package. The observed changes in product stability may adversely affect the products bioavailability profile, even though the potency of the active drug remained within USP specification range of 90–110%. Study results suggest product quality can be negatively impacted even when using USP Class A repackaging materials.

Bioremediation of leachate from a green waste composting facility using waste-derived filter media

The evaluation of two waste-derived materials used to treat compost leachate by biofiltration is described in this paper. Nine biofilters were constructed using 240l, high density polyethylene containers. Three containers were filled without compaction with 200l of each of three types of filter media. Waste-derived filter media (compost and oversize) were compared to a mineral control (granite chips). The filters were fed with compost leachate from a typical green waste composting facility at hydraulic loading rates ranging from 0.05m3/m3/day to 0.5m3/m3/day over a period of twelve months. The oversize medium emerged as the most effective demonstrating characteristics of consistency of effluent quality and resilience to stress. The oversize medium produced an effluent of <10mg/l ammoniacal nitrogen on >95% of sampling occasions. The organic component of compost leachate was dominated by compounds that proved to be recalcitrant to biodegradation. The solids content of the treated effluent remained too high to be acceptable for direct discharge to a watercourse without further treatment and if discharge to a watercourse is to be considered, a polishing stage (e.g., reed bed) able to remove solids and dampen occasional peaks of ammoniacal nitrogen should be employed.

Composition and Characteristics of Excavated Materials from a New Jersey Landfill

The composition of material excavated from the Burlington County landfill in New Jersey was determined, and the major reclaimed fractions characterized. Based on a waste age map, 98 samples (80kg each) collected from 13 gas extraction well borings were handsorted into 14 fractions and fines (<2.54cm) that fell through the screen were collected. At least 50%, by weight, of the material was fines. The most abundant oversize materials (overs) fractions, by weight, were miscellaneous items, wood, other plastics [not polyethylene terephthalate or high density polyethylene containers], and paper. Less paper was found in the oldest (7.5–11.5years) section of the landfill (P<0.10), most likely due to microbial degradation. Several of the characteristics of the materials excavated from the landfill, such as temperature, particle size, bulk density, volatile solids, and contamination were correlated with the age of the deposits made. High levels of adherent soil will likely prove to be an insurmountable obstacle to recycling most excavated waste fractions other than fines unless further processing is pursued.