Hsin-Neng Hsieh

Considerations in disposal of phenolic waters

Concentrations of phenol in water as low as 1 mg/L make it unsafe for human use. Thus, the disposal of phenolic waters poses a major problem. In this paper, an actual case study of disposal phenolic waters from a producer gas plant in India is discussed. Several methods for the disposal of phenolic waters were considered. One of the options involved construction of an earthen embankment for storing slag and phenol. This pond will be located near a river. So a concern exists regarding river pollution. Details of this and the other options considered and the cost analyses are presented. All the relevant aspects of the methods to be considered, including the geotechnical, economical, and environment concerns that influenced the decision making process to arrive at a final solution to the problem, are discussed.

Sustainable management of household solid waste.

In most countries, the majority of household solid waste is landfilled because of associated low capital, operation and maintenance costs. However, many existing landfills have exhausted their handling capacities and new facilities are faced with the problem of siting. Alternatives to traditional landfill practice are required to achieve sustainability in managing solid waste. This manuscript discusses an advanced landfill concept, referred to as a biocell, which involves sequential application of anaerobic degradation, aerobic decomposition and waste mining in a single waste cell. Biodegradation of waste in the biocell is enhanced through leachate re-circulation coupled with landfill gas collection in the anaerobic phase and air injection in the aerobic phase. The biocell is expected to realise sustainability by reusing the location where solid waste is treated, thereby eliminating the need of new land for waste disposal. Environmental controls also eliminate ground/surface water contamination and harmful landfill gas emissions.

Origin, properties and disposal problems of chromium ore residue

Chromium mining operations were conducted in the United States during the first fifty years of this century. During this period, large amounts of chromium waste were produced and used as fill in some areas. Over a period of time, toxic chromium compounds leach out of the ore residue. This poses a severe threat. Structural distress, ground and surface water pollution and parking lot deterioration have been reported in the areas where chromium residue was used as fill. Information regarding chromium residue disposal is rather limited and not readily available. The purpose of this paper is to address this problem and to discuss the production and properties of chromium, and the available technologies for the control and treatment of chromium residue.

On achieving the state's household recycling target: A case study of Northern New Jersey, USA

In recent times, the State of New Jersey (USA) has been making attempts at promoting recycling as an environmentally friendly means of attaining self-sufficiency at waste disposal, and the state has put in place a 50% recycling target for its municipal solid waste stream. While the environmental benefits of recycling are obvious, a recycling program must be cost effective to ensure its long-term sustainability. In this paper, a linear programming model is developed to examine the current state of recycling in selected counties in Northern New Jersey and assess the needs to achieve the states recycling goal in these areas. The optimum quantities of waste to be sent to the different waste facilities, which include landfills, incinerators, transfer stations, recycling and composting plants, are determined by the model. The study shows that for these counties, the gap between the current waste practices where the recycling rate stands at 32% and the states goal can be bridged by more efficient utilization of existing facilities and reasonable investment in expanding those for recycling activities.

Correlation of compound properties with biosorption of organic compounds

Abstract The sorption of organic compounds by inactive microbial biomass was investigated. The sorption isotherms were linear over the range of concentrations studied. The linear partition coefficients (Kp) were directly related to organic carbon content of the biomass. Octanol/water partition coefficient is a much better predictor of extent of adsorption on biomass than aqueous solubility.

Adsorption of organic compounds by microbial biomass

The adsorptive capacity of phenol, chlorophenol, chlorobenzene and ethylbenzene by inert microbial biomass was studied. Desorption and reversibility of adsorption processes were also investigated. The experimental results suggest that the adsorption process of liquid organic compounds can be expressed by the Freudlich Adsorption Isotherm. Sorption capacity is strongly correlated to molecular properties such as water solubility and octanol/water partition coefficient. The combination of lower solubility and higher octanol/water partition coefficient favors the adsorption by microbial biomass. Desorption studies indicated that there are considerable amounts of desorption of phenol and chlorophenol but not chlorobenzene and ethylbenzene. Adsorption by microbial biomass is not completely reversible.

A QSAR model for desorption of halogenated aliphatics from biosolids

Abstract Data collected from different wastewater treatment processes have provided statistically significant evidence that many toxic organic contaminants concentrate to several orders of magnitude greater than influent concentrations in industrial and municipal wastewater sludges. Because of the reversibility of sorption processes, it is possible for sorbed organic compounds to desorb at a later time, hence making disposal of these sludges a potential problem. Although a number of models have been developed to predict sorption parameters, they have all been based on empirically derived descriptors, the validity of which is seriously compromised by the variation in available data for these parameters. In this study, a reliable QSAR model based on theoretically derived molecular connectivity indexes has been developed to predict the release of halogenated aliphatic hydrocarbon compounds from activated sludge solids. Model development was conducted using a statistically designed training set of compounds.

Competitive adsorption of organic compounds by microbial biomass

Abstract This study investigated the effect of competitive adsorption of liquid organic compounds on inactive microbial biomass in bisolute solution systems. Phenol‐nitrophenol, phenol‐ chlorophenol, nitrophenol‐chlorophenol, and chlorobenzene‐ethylbenzene systems were selected for the analysis. The experimental results suggest that although the amount of each solute adsorbed on the biomass can be reduced significantly by the presence of a second solute, the combined adsorptive capacity was greater than that for either of the individual substances from its pure solution. The octanol/water partition coefficient(Kow) indicates the relative extent of adsorption better than the aqueous solubility(S).

Characterization of Water Treatment Residuals and Their Beneficial Uses

Technologies have been developed and tested for the beneficial use of water treatment residuals. Application of these techniques depends on the understanding of the property of the residuals. Ten samples were collected, tested in the laboratory. The properties of the residuals and beneficial uses of residuals are also provided. Lime residuals can be used in agricultural soil conditioning, reclamation of acidic soils and cement production. Iron residuals are employed for iron recovery and desulphurization. Alum residuals are utilized in brick making and composting.

Physical characterization of water treatment plant residual and top soil mixtures

Disposal of water treatment plant residuals is not economically feasible due to their high moisture contents, high compressibilities and very low shear strengths. This paper evaluates the physical and geotechnical characteristics of water treatment residual-top soil mixtures for beneficial reuse in construction and land application. Index, compaction, consolidation, strength and durability tests were performed in accordance with the relevant ASTM standards. It was observed that the plasticity of the mixtures decreased and handling (compaction) and other engineering characteristics improved due to the addition of top soil to residuals. There is a potential for these mixtures to be used as liner material for landfills.