Waste PEEP index

Measurement endpoints result in a waste PEEP index value (similar to the PEEP index presented in the Chapter 1 of this volume) resulting from the integration of different bioassay responses. ... 

The waste PEEP index formula can be employed with any appropriate number and type of tests depending on laboratory expertise and means (any bioassay can be replaced by another or added to the proposed list). In theory, waste PEEP index values can vary from 0 to infinity. In practice, it has been shown to produce values ranging from 0 to 10, thereby simulating a readily-understandable "waste scale" indicative of ecotoxic impact. 

Where n is the number of bioassays exhibiting calculable (geno)toxicity responses, N is the total number of bioassays carried out, Ti is (geno)toxicity expressed in TU of each test. In quantifying the toxicity of leachates produced in the prerequisite study or in the WASTOXHAS procedure, the waste PEEP index allows clear identification of the most problematic wastes requiring priority in terms of clean-up action or attention. 

Figure 5. Prerequisite study - Comparison of the waste PEEP index values calculated for a municipal solid waste incinerator bottom ash (BA) and a slag from a second smelting of lead (2SL) as a function of each experimental liquid-to-solid ratios (L/S). Each waste PEEP index value was calculated using ecotoxicological results presented in Table 5 (see Section 5.6 for details of calculations).

Based on the different results obtained for the algal and Microtox tests (Figures 7 and 8), a waste PEEP index value was calculated for each waste and each L/S ratio assessed. Each waste index value was then plotted as a function of the corresponding L/S ratio (Fig. 9) and a simple non-linear regression fit (Power model, y = axb) was applied to predict the ecotoxicological hazard potential of leachate fluxes between L/S 4 and L/S 30 ratios. 

Table 8 summarizes pH, conductivity, ecotoxicological results and the corresponding waste PEEP index values obtained for the accumulated percolates recovered in situ for each waste. Measurements of pH remained relatively constant, but conductivity decreased in relation to L/S ratio, as observed before in the column study. 

Table 9 gives an overview of results obtained from the column tests and the field tests for BA and 2SL wastes up to an L/S ratio of 2 and an L/S ratio of 8, respectively. This outlook allows a comparison of the two procedures based on the sensitivity responses of the algal and Microtox tests and on the waste PEEP index values for L/S ratios experimented in the field. For the purposes of this comparison, waste PEEP index values for the field percolates were recalculated using results of both tests presented in Table 8. 

Waste Procedure L/S ratio Sensitivity of ecotoxicity tests Waste PEEP index value Waste PEEP trend... 

While the PEEP index can theoretically be employed to assess the toxic potential of varied liquid media and groups of specific chemical products of interest (Section 8.3), it was originally conceived to appraise that of liquid wastes of point source discharges to aquatic environments. The index is thus described for this purpose in this section. 

Lambolez (1994) and Bispo (1998) showed that this kind of index can be used for integrating different results obtained from solid waste leachates without having to take into account the ME Vs obtained after biodegradation nor the flow (Q in the PEEP formula) specific to effluents. The Waste PEEP formula defining a PEEP index for waste then becomes ... 

Birkholz, D., Belton, K. and Guidotti, T. (2003) Toxicological evaluation for the hazard assessment of tire cmmb for use in public playgrounds, Journal of Air Waste Management Association 53, 903-907. Costan, G., Bermingham, N., Blaise, C. and Ferard, J.F. (1993) Potential ecotoxic effects probe (PEEP) a novel index to assess and compare the toxic potential of industrial effluents, Environmental Toxicology and Water Quality 8, 115-140. 

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