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Investigates the fate and toxicity of continuous feeding with increasing dosage of heavy metal ions – Cu, Pb, Zn, Cr(VI) – on biogas production from anaerobic digestion of sewage sludge. The efficiency of the system (as measured by biogas production and volatile organic matter removal rate) was reduced for about 35 days before returning to a steady state with the toxicity ranking Cu > Cr (VI) > Pb >Zn. Also looks at the effect of two “pulse” doses of the metals.

Examines the treatability of highly polluted wastewater from a dairy factory prior to its final disposal into the public sewerage system. Physical treatment of the dairy waste via aeration, followed by settling, resulted in a 25 per cent chemical oxygen demand (COD) reduction and elimination of odours. Chemical treatment achieved almost 50 per cent removal of COD. The chemical‐biological process using activated sludge/trickling filter resulted in 64 per cent and 90 per cent removal of the volatile organic matter value respectively. However, the quality of the waste produced does not meet with the National Regulatory Standards for wastewater disposal into the sewerage system. Chemical‐biological treatment using an upflow anaerobic reactor succeeded in reducing the pollutional parameters to coincide with the limits of the Egyptian Law 93/1962 and produces biogas as a source of energy at a rate of 0.39m³/kg COD removed.

The main purpose of this study is to provide technical support for industrial firms in a new Egyptian industrial city in order to comply with the National Regulatory Standards for wastewater discharge into the public sewerage network.

An execution plan has been prepared to identify the existing environmental status of all the enterprises in the city. To accomplish the planned activities, relevant information was collected from the available records in the city. A unified questionnaire format has been designed for all enterprises including all activities and information required for this study. Accordingly, industries were classified according to their activities and sizes. The information was fed to the computer using a database to control data entry, analysis, and retrieval. Also, the work plan included industrial auditing, wastewater characterization, and application of pollution prevention measures and treatment of end‐of‐pipe.

Statistical analysis of the collected data showed that 119 enterprises were distributed among different industrial sectors. The size of factories according to number of employees is categorized as micro, small and medium. Characterization of industrial wastewater produced from 37 plants indicated that 50 percent thereof do not comply with the Egyptian environmental laws, for industrial wastewater discharge into the public sewage network. In this study, three factories were selected to solve their environmental problems. Treatability studies and/or pollution prevention approaches for the selected factories were carried out and the recommended solutions were implemented and proved to be cost‐effective.

This paper provides the guidelines for other factories in this Egyptian industrial city to be environmentally friendly via compliance with the local regulatory standards. Dissemination of the achieved results can be applied by other industrial cities in Egypt.

Pre‐treatment of wastewater discharged from a potato‐chips factory was the subject of this study. Wastewater discharged from this factory is characterized by high values of BOD, TSS and oil and grease (3,685, 4,115 and 169mg/l, respectively). Treatability studies via continuous aerobic and anaerobic methods treatment have been investigated. The results obtained showed marked improvement in the quality of the treated effluent using packing material versus the upflow anaerobic sludge bed reactor (UASB) without packing. An extra removal in COD (53 per cent), BOD (61 percent), TSS (52 per cent) and oil and grease (46 per cent) was obtained. Corresponding residual values were 398mgO₂/l, 235mgO₂/l, 108mg/l and 38mg/l, respectively. Based on the laboratory results, engineering designs and economic evaluation of the different treatment systems were developed.

The main purpose of this study is to investigate the bioaccumulation pattern and fate of heavy metals in duckweed‐based wastewater treatment ponds with different depth.

Three replicates of four reactors were used in this experiment. The reactors were randomly distributed on the bench and filled with 50 percent diluted sewage for the control reactors whereas diluted sewage mixed with 5 mg Pb/l and 5 mg Zn/l was used for the treatment reactors. The reactors were stocked with Lemna gibba at 1,000 g fresh weight per each square meter. The culture tanks were exposed to temperature range of 21‐25°C and light regime of 16 hours light using halogen lamps and 8 hours dark. The light intensity was maintained around 200 μ E m⁻² S⁻¹. The experiment extended for 30 days. Regular monitoring of the growth performance of duckweed was carried out with subsequent analysis of dry matter, heavy metals, phosphorous and nitrogen content. Composite samples from the water phase were subjected to the analysis of ammonia, nitrite, nitrate, orthophosphate and sulfate concentration. The analysis of sediment and biofilm were carried out at the end of the experiment. Interpretation of results was carried out using one‐way analysis of variance.

Statistical analysis showed a significant reduction in the growth rate of duckweed within the first five days exposure time. After five days exposure, the growth rate in the treatments returned to the normal growth till day 15 after which the growth became significantly lower in the small and medium scale ponds. The results revealed that zinc is more bio‐available than lead and both metals are mostly precipitated in the sediment probably as sulfides.

The results help in enhancement of heavy metals removal in a small anaerobic pretreatment unit before entering to the pond system by sulfate addition.

The results of the study confirm the positive effect of pond depth in reducing the heavy metal toxicity to the duckweed‐based wastewater treatment ponds.

About 50 epidemiological reports about possible associations between cancer morbidity and exposure to electromagnetic fields (EMFs) were published between 1979 and 1994. The majority of them (60‐75 per cent) documented a slight (1.5 to twofold) but significant increase in the incidence of certain rare forms of neoplasms (leukaemia, lymphoma, brain tumours). A limited support for carcinogenic potencies of EMFs is provided from cellular studies, but the effects appear to be generally weak, transient and difficult to replicate. Concludes that the available evidence associating cancer and EMF exposure is too tenuous to be convincing but too consistent to be ignored. Further progress needs better quantification of exposure levels and conditions, evaluation of dose‐effect relationships and liability to confounding carcinogenic factors that may influence morbidity rates in the investigated populations.