Waste minimization phases

USEPA. Waste Minimization Benefits Manual, Phase I. U.S. Environmental Protection Agency Washington, DC, 1988. 

This VIP is considered by some engineering contractors to have become standard practice. For those where it is not standard practice, the waste minimization VIP should be executed in a formal workshop with an experienced facilitator with project owner and engineering contractor representatives always involved. A cold eyes reviewer with extensive experience should also be included to add a nonbiased perspective. The waste minimization VIP should be implemented at the feasibility phase (FEL-2) when preliminary PFDs and heat and material balances are available. 

The environmentally benign, nontoxic, and nonflammable fluids water and carbon dioxide (C02) are the two most abundant and inexpensive solvents on Earth. Water-in-C02 (w/c) or C02-in-water (c/w) dispersions in the form of microemulsions and emulsions offer new possibilities in waste minimization for the replacement of organic solvents in separations, reactions, and materials formation processes. Whereas the solvent strength of C02 is limited, these dispersions have the ability to function as a universal solvent medium by solubilizing high concentrations of polar, ionic, and nonpolar molecules within their dispersed and continuous phases. These emulsions may be phase-separated easily for product recovery (unlike the case for conventional emulsions) simply by depressurization. 

Smith K, Fry CV, Tzimas M, The use of solid supports and supported reagents in liquid phase organic reactions, in Chem. Waste Minimization (Ed. J.H. Clark), pp. 86-115, 1995, Blackie, Glasgow, UK. 

In this phase, several possible waste-reduction measures are identified that can be proceeded to the analysis phase. Different waste-minimization programs may require varying degrees of effort, time, and financial resources ... 

Waste auditing is as important as any other step in a waste-minimization or cleaner-production project. A proper waste audit should essentially provide a platform on which the rest of the project would be built. It should be a repository of all data and information that would be required to carry out the rest of the phases. As information is the strength so is a successful waste audit. 

The principal intent of a waste audit is to critically assess various inputs, processes, and outputs to find methods and practices for minimizing waste and reducing the resource consumption in a sustainable and environmentally benign way without compromising the commercial interest of the company. The waste audit phase would typically be a data collection and information synthesis phase that explores the current situation. Traditionally, an industrial waste audit also develops a list of waste minimization options and undertakes some preliminary technical and economic feasibility studies on the identified options to recommend about these opiions. 

The conceptual phase of a project starts before there is a project. This phase of the project is where a plan for satisfying a need will be conceived (Fig. 2). Definition of the need will start the process. A method of satisfying the need will be the result. The need may be for increased capacity, new product, elimination of bottlenecks in existing facilities, modernization, meeting new regulations, energy efficiency, and waste minimization, to name a few. 

The next section describes measurements of interfacial tension and surfactant adsorption. The sections on w/c and o/c microemulsions discuss phase behavior, spectroscopic and scattering studies of polarity, pH, aggregation, droplet size, and protein solubilization. The formation of w/c microemulsions, which has been achieved only recently [19, 20], offers new opportunities in protein and polymer chemistry, separation science, reaction engineering, environmental science for waste minimization and treatment, and materials science. Recently, kinetically stable w/c emulsions have been formed for water volume percentages from 10 to 75, as described below. Stabilization and flocculation of w/c and o/c emulsions are characterized as a function of the surfactant adsorption and the solvation of the C02-philic group of the surfactant. The last two sections describe phase transfer reactions between lipophiles and hydrophiles in w/c microemulsions and emulsions and in situ mechanistic studies of dispersion polymerization. 

Analysis and Plans An important approach is analysis of waste streams and formulation of a hazardous waste reduction plan. Some have suggested three phases in a waste minimization program. Each phase must deal with hazards, risk, and economics of options. It is important to involve both managers and workers in each phase. Follow-up for each phase must evaluate the effectiveness of actions taken or to be taken ... 

The waste minimization procedure, which is depicted in Fig. 2.2, consists of four phases ... 

The phase used in HSWA was hazardous wastes. The assumption can be made, therefore, that the waste minimization regulations required by HSWA were intended to cover only those solid wastes regulated as hazardous waste under RCRA. 

The waste minimization options that are successfully screened in the assessment phase then undergo a more detailed feasibility analysis. Most important, the feasibility analysis consists of three steps technical evaluation, economic evaluation, and implementing option selections. 

A sample worksheet used in making waste minimization assessments is shown in Table 2.3. Designed to clarify the assessment procedure, the worksheet includes the phase of each step in the procedure, its number and title, and a brief description of its purpose or other useful remarks. 

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