Abstract: The study assessed the effectiveness of Pawpaw
(Carica papaya) wood in reducing the concentrations of heavy
metals in wastewater acting as a bio-sorbent. The following heavy
metals were considered; Zinc, Cadmium, Lead, Copper, Iron,
Selenium, Nickel and Manganese. The physiochemical properties of
Carica papaya stem were studied. The experimental sample was
sourced from the trunk of a felled matured pawpaw tree. Wastewater
for experimental use was prepared by dissolving soil samples
collected from a dump site at Owerri, Imo state of Nigeria in water.
The concentration of each metal remaining in solution as residual
metal after bio-sorption was determined using Atomic absorption
Spectrometer. The effects of pH and initial heavy metal concentration
were studied in a batch reactor. The results of Spectrometer test
showed that there were different functional groups detected in the
Carica papaya stem biomass. There was increase in metal removal as
the pH increased for all the metals considered except for Nickel and
Manganese. Optimum bio-sorption occurred at pH 5.9 with 5g/100ml
solution of bio-sorbent. The results of the study showed that the
treated wastewater is fit for irrigation purpose based on Canada
wastewater quality guideline for the protection of Agricultural
standard. This approach thus provides a cost effective and
environmentally friendly option for treating wastewater.
Abstract: This study was conducted to evaluate the manganese
removal from aqueous solution using Banana peels activated carbon
(BPAC). Batch experiments have been carried out to determine the
influence of parameters such as pH, biosorbent dose, initial metal ion
concentrations and contact times on the biosorption process. From
these investigations, a significant increase in percentage removal of
manganese 97.4% is observed at pH value 5.0, biosorbent dose 0.8 g,
initial concentration 20 ppm, temperature 25 ± 2°C, stirring rate 200
rpm and contact time 2h. The equilibrium concentration and the
adsorption capacity at equilibrium of the experimental results were
fitted to the Langmuir and Freundlich isotherm models; the Langmuir
isotherm was found to well represent the measured adsorption data
implying BPAC had heterogeneous surface. A raw groundwater
samples were collected from Baharmos groundwater treatment plant
network at Embaba and Manshiet Elkanater City/District-Giza,
Egypt, for treatment at the best conditions that reached at first phase
by BPAC. The treatment with BPAC could reduce iron and
manganese value of raw groundwater by 91.4% and 97.1%,
respectively and the effect of the treatment process on the
microbiological properties of groundwater sample showed decrease
of total bacterial count either at 22°C or at 37°C to 85.7% and 82.4%,
respectively. Also, BPAC was characterized using SEM and FTIR
spectroscopy.
Abstract: Nowadays harmonization of sanitary and hygienic standards of environmental quality with international standards is crucial part of integration of Russia into the international community. Harmonization of Russian and international ambient air quality standards may be realized by risk-based standards development. In this paper approaches to risk-based standards development and examples of these approaches implementation are presented.
Abstract: The contamination of 15 ground water resources
of a selected region earmarked for the emergency supply
of population has been monitored. The resources have been selected
on the basis of previous assessment of natural conditions
and the exploitation of territory in their surroundings and infiltration
area. Two resources out of 15 have been excluded from further
exploitation, because they have not met some of the 72 assessed
hygienic indicators of extended analysis. The remaining 13 resources
have been the subject of health risk analysis in relation
to the contamination by arsenic, lead, cadmium, mercury, nickel and
manganese. The risk analysis proved that all 13 resources meet
health standards with regard to the above mentioned purposefully
selected elements and may thus be included into crisis plans. Water
quality of ground resources may be assessed in the same way
with regard to other contaminants.