Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewater effluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in water bodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite (NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before and after disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Samples were adsorbed using silica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonella typhimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plant genotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test). Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewater samples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphase aberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClO does not lead to the formation of significant amounts of genotoxic by-products.

Genotoxic and ecotoxicologic effects of urban wastewater disinfected with sodium hypochlorite or peracetic acid were analyzed. The formation of genotoxic species was studied by determining clastogenic and mutagenic activity of aqueous samples and their extracts with in vivo and in vitro tests, respectively. In particular, we have applied citogenetic tests to Allium cepa roots and Tradescantia inflorescence (Allium cepa test and Tradescantia/micronuclei test) and reversion test to Salmonella typhimurium according to the microsuspension procedure (Kado test). The latter is the method of choice for the analysis of complex matrices due to its high sensitivity and specificity. The mutagenic activity of disinfected effluents was similar to the corresponding untreated wastewater both sampled in four different periods. Therefore, the disinfection process did not seem to contribute to aquatic mutagenicity in the examined range of biocide concentration. The potential toxicity of disinfected wastewater for aquatic organisms was evaluated using Daphnia magna. The acute toxicity of peracetic acid in sewage was 0.4 mg/L (24 h E(L)C50). By comparing this value with peracetic acid concentrations detected in effluents from a pilot plant it is expected that treated wastewater would show acute toxic effects on aquatic organisms. Dissociation compounds (hydrogen peroxide and acetic acid) and possible by-products of peracetic acid did not seem to contribute significantly to the toxicity of sewage treated with peracetic acid.

Peracetic acid (PAA) use in wastewater disinfection was assessed by examining its performances in a pilot plant fed by the effluent from a conventional activated-sludge treatment plant. The influence of PAA initial concentrations (0.5-4.0 mg/l) and contact times (8-38 min) on the presence of seven microorganisms (total coliforms, fecal coliforms, fecal streptococci, Escherichia coli, Pseudomonas sp., Salmonella sp., and bacteriophages anti-E. coli) and on residual biocide and halogenated organic compound (AOXs) concentrations were evaluated. The data so obtained were compared to the corresponding results acquired using sodium hypochlorite (HYP) in the same experimental conditions. The biocide effect of PAA against total and fecal coliforms, E. coli, Pseudomonas sp. and Salmonella sp. was similar to that shown by HYP. The former disinfectant was, however, less efficient than the latter in the reduction of fecal streptococci and bacteriophages anti-E. coli. In both cases the biocide quantities initially introduced in the sewage resulted in the presence of significant concentrations at the end of the contact time. No significant variation of AOX content was detected in the effluent treated with PAA, whereas a progressive increment of such compounds was found when increasing quantities of HYP were added to the sewage.

In two previous articles some of the present authors had assessed and proposed the direct use of an analytical capillary column with a bonded phase for both trapping and later GC analyzing organic compounds. A few factors influencing band dispersion of the solute had been investigated and a mathematical relationship developed to calculate the degree of retained-substance dispersion starting from GC peak widths.

Burial grounds are generally provided by local authorities in cemeteries (subject to planning consent and to compliance with any considerations for environmental health). Their design has been submitted to studies of hydrogeological characteristics of soil with regard to its ability to purify wastewater coming from corpse decomposition, its ability to avoid the infiltration of pollutants in groundwater, and its ability to skeletonize buried corpses within the given times foreseen by the law in force. Greater environmental awareness has necessitated that new and existing burial grounds are assessed to determine the environmental load which they could release to soil or any downstream component. This problem arises in countries where there is a high density of built-up areas, a custom of disposing of the dead by burial, a lack of available spaces and suitable soils to designate as burial grounds. This paper reports some results from a study carried out on ground lands of Italy in order to revise articles 82 and 83 of the Decree No 285 of 1990 in force in relation to burial grounds. Soil permeability to water and air is a parameter of critical importance in relation to purification and/or diffusion of leachates from inhumed corpses in the soil, and in relation to its influence on the time necessary to completely skeletonize a human corpse.

This study was carried out in order to revise the law in force in Italy (Decree no. 285 of 1990) in the field of cemeteries, funeral services and all that concerns disposal of human remains. Countries which have space limitation for existing cemeteries or difficulty finding new suitable areas for cemetery planning have to re-examine all the systems of disposal of human remains (cremation, burial by ground and by walled-graves) and all the parameters involved in the process of the bodies decomposition. In this paper, on the basis of data collected from some municipal cemeteries in Italy, the reasons that have led to current insufficient areas for burial are analyzed. It is a very difficult question to single out possible solutions because they involve technical parameters as well as a new way of considering the burial. In this paper some possible solutions to the problem of recovering burial sites are analyzed and some guidelines for the planning of municipal plan-cemeteries are outlined.

In a previous study (Microchem. J. 59 (1998) 246–257) a systematic approach had been developed to optimize the experimental conditions applied during microwave-assisted mineralization of sewage-sludge samples. An innovative elaboration of data acquired by real-time monitoring of temperature and pressure inside a closed vessel heated by microwave radiation had been performed to determine thermodynamic and kinetic behavior of sample–HNO3 mixtures. The difference (Δpressure) between the pressure recorded during sample–HNO3 heating and the corresponding vapor pressure of the pure reagent had been calculated as a function of temperature. Only concentrated HNO3 had been chosen as a digesting reagent to reduce the complexity of the observations to a single power-absorbing component. In this work the performance of other digesting reagents prepared by mixing HNO3 with H2O2 was tested. Results obtained by examining Δpressure vs. temperature graphs were compared with treatment efficiencies determined by measuring total-organic-carbon variation as well as heavy-metal recovery in the digests.

A comparative study on peracetic acid and sodium hypochlorite in inactivating bacteria and viruses was carried out. Therefore the disinfection actions of peracetic acid, in comparison with sodium hypochlorite, was evaluated against the usual indicators of faecal contamination, the pathogen Salmonella, Pseudomonas spp., bacteriophages anti-Escherichia coli, F+/phage and the phage of Bactericides fragilis B40-8 and enteroviruses. Under the experimental conditions, no representative results were obtained for enteroviruses and phages because of their low concentration in the sewage effluent. On the other hand, the indicator organisms were reduced substantially by the sodium hypochlorite and peracetic acid concentrations, while more variable results were obtained against Pseudomonas and bacteriophages anti-Escherichia coli.