A procedure for stabilization/solidification of loose waste from the manufacture of Ni and Cd electrodes, which represents a nonutilizable and noncombustible hazardous waste, has been worked out. The procedure comprises solidifying the waste by means of an anionic slow-setting aqueous-asphalt emulsion with subsequent formation of an asphalt coating on the surface of solidified waste by spraying with an anionic rapid-setting aqueous-asphalt emulsion. This asphalt coating represents a secondary barrier against leaching of pollutants into the environment. Results of leachability tests with water (Czech Republic regulations) as well as with acetic acid (toxicity characteristic leaching procedure test, EPA) are evidence of the successful stabilization of given waste. Values of determined leachability parameters of test specimens prepared from stabilized waste are very favorable and, in addition, virtually the same as those of blank test. This demonstrates, in a convincing manner, efficiency of the developed stabilization/solidification procedure. Results have also shown the toxicity characteristic leaching procedure test is indispensable for the assessment of toxic metals leachability. Performed tests have shown a marked drop in ecotoxicity from relatively high toxicity of untreated waste leachate to low toxicity of stabilized waste leachate.

A statistical analysis of the measurement performance of five mobile nondestructive assay systems currently in use for radioassay of nuclear waste was performed. Actual versus reported isotopic mass composition, reported versus actual measurement uncertainty, detection capability, and low level versus transuranic waste determination were assessed based on measurements of 11 surrogate waste drums. In terms of percent recovery the systems, for the most part, exhibited reasonable capabilities for estimating isotopic quantities in the surrogate waste drums. (By reasonable we mean, for example, that recovery values were in a range of 40% to 160% for most of the configurations tested.) While difference in performance on individual drums was quite large in some cases, nonparametric analysis of variance results for total plutonium and ${}^{241}\mathrm{Am}$ showed no statistically significant differences in the overall average percent recovery values for the systems evaluated. A similar analysis of the replicate standard deviations indicated significant differences between systems with regard to precision of measurements of total plutonium but not ${}^{241}\mathrm{Am}\text{.}$ The weakest aspect of system performance was the reporting of measurement errors. Reported measurement error values routinely underestimated actual values for certain surrogate waste configurations.

On-line monitoring of oxidation reduction potential (ORP) was conducted at the full-scale aeration basin operated with intermittent aeration schedules and fed with the wastewater generated from fruit fly rearing facility owned by the California Department of Food and Agriculture, Waimanalo, Hawaii. The characteristics of the wastewater were fluctuated, severely. The 90 percentile level of total chemical oxygen demand, total Kjeldahl nitrogen, and total suspended solids for the wastewater are 5,200, 142, and 3,350 mg/L, respectively. Two aeration schedules of 4 h aeration/2 h nonaeration and 3 h aeration/3 h nonaeration were investigated in this study. Typical ORP curve with bending points of β (beginning of denitrification), χ (disappearance of nitrate), and plateau $(d\mathrm{ORP}/\mathrm{dt}=0)$ were observed for both aeration schedules. The α (end of nitrification) value couldn’t detect in the aeration schedule of 3 h aeration/3 h nonaeration because of the ORP fluctuation at the onset of aeration. However, the α value detected without any difficulty for the aeration schedule of 4 h aeration/2 h nonaeration. This is due to the relatively lower gradient of the reduced substance concentration between supernatant and settled sludge layers during the air-off period. Through the ORP monitoring of the full-scale aeration basin treating fruit fly rearing facility wastewater, the aeration time can be reduced from 4 h to 3 h without deterioration of organic and nitrogen removal efficiencies. By reducing the aeration time, 25% of energy cost for aeration can be saved. From the result of real time monitoring of ORP response and water quality analysis of nitrogen, the behaviors of nitrogen forms are closely related to the ORP response. Therefore, the ORP monitoring is a practical and easy tool for the evaluation of the degree of nitrification and denitrification condition in biological wastewater-treatment systems.

This study presents the results of two leaching tests for cement mortars. Industrial sludge slag is employed as a fine aggregate to determine the mortar’s leaching tendency. The proportion of quartz sand replaced by slag in cement mortars was 0, 10, 20, 30, 40 and 50% (weight-to-weight ratio), and the cement mortars were cured for seven, 28, and 90 days. Toxicity characteristic leaching procedure (TCLP) and semidynamic leaching test (SDLT) methods were used to determine the leaching characteristics of both sludge slag and cement mortars. All the TCLP leaching rates were lower than 1%. TCLP leaching results reveal that the concentrations of slag and cement mortar were not significantly related to the replacement ratio, but declined as the curing period was increased. The results of the SDLT show that heavy metal concentrations in the long-term leachate increased with the replacement ratio, as expressed by the input amounts of heavy metals and the leaching period. The TCLP and SDLT leaching results comfortably satisfy the regulations, proving the safety and suitability of slag utilized as fine aggregate.

Investigations were carried out to study the heavy metal content in the bottom ash from the medical-waste incinerator of Ratchasima-Thonburi Hospital in the northeastern city of Nakhon Ratchasima in Thailand. Relationship between particle size and heavy metal concentrations were determined in the bottom ash and in simulated leachate. The following four metals were selected for this study: lead, silver, iron, and zinc, in the four particle sizes >9.5 mm, 9.5–4.75 mm, 4.75–0.5 mm, and less than 0.5 mm, respectively. The average concentrations of lead, silver, iron, and zinc in bottom ash were 765.3, 327.9, 314, 121.2, and 18,710.7 mg/kg, respectively. The toxicity of leachate from bottom ash was investigated for these metals. The concentrations were compared with the U.S. EPA limits and Thailand’s standards for heavy metals in the leachate of hazardous waste. The average concentrations of lead, silver, iron, and zinc in the simulated leachate were 0.1, 0.1, 0.2, and 0.3 mg/L, respectively, well below the limits set by EPA and Thai standards.

This paper presents a detailed overview of endocrine-disrupting chemicals in which the writers discuss the disrupter agent modes of action, the impact evidence on humans, the different methods of analysis, and the difficulties met with biological screening tests. A discussion of exposure duration follows, on the deficiencies of both long-term and single-generation experiments, which will be important to future study. The present review also discusses how EDCs are discharged into municipal and industrial wastewater and can pass through wastewater-treatment plants and enter the aquatic environment (into rivers and seas). In the end, the writers present different alternatives and techniques, which several researchers continue to develop, and adapt to treat the aqueous solutions and mainly the wastewater.

Source water from King-Men Reservoir water in Taiwan was treated by alum and polyaluminum chloride coagulation, and the corresponding natural organic matter was fractionated by ultrafiltration membranes for determining its molecular weight (MW) distribution to provide the baseline information for further investigation. Due to the characteristics of the source-water nature, a lower alum dosage could reduce the total organic carbon (TOC) concentration by a great amount (25%), while the difference in TOC removal efficiency was found to be insignificant at a higher dosage (60–90 mg/L) and even operating in a lower pH range. The results show that the larger MW coagulant polyaluminum chloride, having higher-charge neutralization and bridging capacities, exhibits better performance than the lower MW alum. In addition, the granular-activated carbon-adsorption process provides a relatively lower THMFP in the treated water at the same level of trihalomethanes and to lower the coagulant doses demand as well.