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A study was designed to investigate the chemical coagulation process for the treatment of the potato food industry wastewater of the “Chipsy factory” located at Abi‐Sier, Egypt. The chemical coagulants used in the study include alum, ferric chloride, calcium chloride, ferric sulphate and Nalco as polymer. Variable doses of these coagulants were examined to determine the optimum dose. Results obtained showed that chemical treatment (coagulation, flocculation, followed by sedimentation) was efficient to reduce the chemical oxygen demand (COD), total suspended solids (TSS) and turbidity significantly. Remarkable variation of the removal efficiency depends on the type of coagulant. Ferric chloride and ferric sulphate were more efficient than calcium chloride. Combination of Nalco with each of the studied coagulants improved the removal efficiency remarkably. Reduction of 91‐94 per cent of turbidity, 93‐97 per cent of COD, and 94‐97 per cent of the TSS was achieved with these combinations.

Examines the effect of pollution along the agriculture highway between Cairo and Alexandria. Different samples of water, soil and plants (clover) were collected from nine variable locations along this highway. Results obtained revealed that the influence of lead precipitating from the atmosphere directly reflects the lead content of soil. Concentration of metals so far did not show any great significant effect.

The removal of nickel and mercury from drinking water, using powdered activated carbon (PAC) and granular activated carbon (GAC) was studied intensively. The water studied was artificially contaminated by Ni and Hg to yield 2mg/l each. Both batch and continuous systems were tested. The time needed to maintain equilibrium and the adsorption isotherm were determined by the batch system. The results obtained were found to be confirmed with Freundlich’s equation, rather than Langmuir or BET. When the PAC was used, the values 1/n and K were 1.59 and 1.02 for Ni and 1.21 and 1.91 for Hg. Relatively similar results were obtained when the GAC was examined. This indicated the stronger adsorbability of mercury compared to nickel. When investigating the continuous system at different contact times the results indicated that increasing the contact time increased the metal : carbon removal efficiency. The overall results showed that the breakthrough points for either Ni or Hg reflected their adsorption isotherms as indicated by k values. Concludes that the addition of an activated carbon filter is recommended for the treatment of drinking water contaminated by heavy metals.

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.

Describes a study carried out to evaluate the accumulation of heavy metals by two different vascular aquatic plants in the artificial wetlands which were constructed for the treatment of municipal wastewater in Berlin, Germany. The studied plants were Pharagmites australis and Schoenoplectus lacustris. The investigated metals were: Zn, Cr, Cu, Fe, Cd, Ni and Pb. The translocation of such metals in the plant roots, stems and leaves was also determined. The level of metals in the influent and effluent of the wastewater, as well as the sludge, was investigated. The concentration factor of each metal by plants and sludge was further studied. Results revealed that P. australis has a higher tendency for the accumulation of metals than S. Lacustris. The level of metals was higher in roots, followed by leaves, then stems. Metals were more concentrated in the sludge than in the plants. Further study showed that the levels of metals in plants grown in the artificial wetlands were higher than in those grown in a “controlled” area. Concludes that vascular plants can act as scavengers of metals from the municipal wastewater while still maintaining a healthy status.

Examines the fate of heavy metals in sewage water and the sludge produced. Investigates the level of metals before and after the use of chemical coagulants as well as throughout every process of the plant. Results reveal that the present upgrading of the plant has a remarkable improvement in the performance of the sewage treatment. Concludes that such upgrading of the plant reduces sewage tax because of the improvement in performance. In addition, the hydrolysis of the pre‐treated sludge can improve the de‐nitrified process and therefore can save energy, while the application of lime can be a substitution for enlarging the plant itself.

Presents the findings of a study conducted to examine the efficiency of the combined anaerobic‐aerobic reactors for the treatment of three different tannery industrial wastewaters, focusing on the fate of chromium and other associated metals. Examines elimination rates of such metals with respect to each successive treatment process. Discusses the correlation between the chemical characteristics of the wastewater influent and effluent along with the level of heavy metals in such wastewater and the produced sludge. Confirms that the use of such sludge in agriculture should be restricted and recommends the recovery of Cr from the tanning sludge.

In this study tannery industrial wastewater was supplied from a leather industry plant in the south of Germany. An anaerobic pilot plant was erected for the treatment of this wastewater. Discusses the effect of such an anaerobic process with special reference to the fate of chronium and the other associated heavy metals throughout the process. The studied metals were Cr, Cd, Pb, Ni, Cu, Fe and Zn. The elimination rate of these metals throughout the anaerobic processes from the wastewater and the increasing rate of metal correlations in the sludge were studied extensively. Levels of Cr, Cu, Fe, Cd, Ni, Pb and Zn in the raw wastewater after acidification were 33.72, 0.13, 1.82, 0.06, 0.19, 0.21 and 1.07 mg/l respectively. In the sludge the levels were 6,296, 16, 141, 31, 12.4, 23 and 94 mg/kg dry weight respectively. The levels of these metals were decreased by stabilization. The overall results revealed that a remarkable decrease has been achieved in the reduction level of metals in the final wastewater. The elimination of such metals reached 98 per cent for Cr, 53.8 per cent for Cu, 81.3 per cent for Fe, 16.7 per cent for Cd, 21.1 per cent for Ni, 72.9 per cent for Zn. On the other hand, such metals were concentrated in the sludge, on the dry weight basis, up to the levels of 13,193 mg Cr/kg, 27.7 mg Cu/kg, 348 mg Fe/kg, 3.2 mg Cd/kg, 13.7 mg Ni/kg, 28 mg Pb/kg and 110 mg Zn/kg. Meanwhile, the studied anaerobic process exhibited significant improvement in the quality of the tannery wastewater to meet the guideline characteristics. However, the partial high level of Cr (III) and the other associated metals in the produced sludge strongly militate against the use of such tannery sludges as manure in agriculture.

The construction industry’s contribution to environmental deterioration is widely established in the literature, implying that addressing this issue will require a coordinated effort from all stakeholders. According to literature, stakeholder involvement without stakeholder management (SKM) is not enough, in ensuring efficient construction waste management (CWM). This study investigates the impact of SKM on efficient CWM by aggregating all relevant SKM variables and measuring their degree of influence on efficient CWM.

This study used a four-stage research approach that included a literature review, a pilot study, a questionnaire survey and statistical analysis. After a thorough examination of the literature, nine essential SKM factors were identified and tested by a questionnaire survey following a pilot study. A total of 310 questionnaires were filled out and returned for analysis (exploratory and confirmatory factor analysis).

The study established that SKM is a unidimensional construct since all the variables extracted unto one underlying component with total variance explained (TVE), accounting for 58.938% of the total Variance in the measure of SKM in efficient CWM. Additionally, the reliability and validity test results satisfied the recommended thresholds, thus justifying the factorability of the construct. Furthermore, the hypothesis test revealed that SKM has a statistically significant impact on efficient CWM, implying that increasing SKM will have a beneficial impact on efficient CWM.

The study is limited to material waste management in the construction industry and the outcome was determined solely by a field survey in Ghana. Extending the study to other jurisdictions would have improved its findings and made them easier to generalise.

The study’s findings are helpful for practitioners and researchers, especially regarding the influence of the eight SKM variables on efficient CWM.

The study’s findings will reduce pollution, thus enhancing public health and encouraging social inclusion through the creation of jobs in the waste management chain.

The uniqueness of this study is anchored on the fact that no CWM study has considered all the eight SKM variables measured in this study at the same time. Also, this study has contributed to the literature by establishing the determinants of SKM in efficient CWM in Ghana.