Feasibility study of organic matter and Ammonium removal using loofa sponge as a supporting medium in an aerated submerged fixed-film reactor (ASFFR)

Biofilm systems are efficient in the removal of organic matter and ammonium from wastewaters. In this study, loofa sponge, a natural product, was used as a supporting medium in an aerated submerged fixed-film reactor to evaluate its performance in removing organic matter and nitrogen from wastewater. Four pilot runs were performed with chemical oxygen demand (COD) concentrations of 100, 200, 300 and 400 mg l-1 to provide an organic loading rate of 0.6, 1.2, 1.8, and 2.4 kg m-3d-1 respectively. In these pilot runs, the influent ammonium nitrogen concentrations were justified to 5, 10, 15 and 20 mg l-1 as N to provide an influent nitrogen loading of 30, 60, 90 and 120 g m-3.d-1 respectively. Although soluble COD removal efficiency greater than 80 percent was achieved up to a loading rate of 2.4 kg m-3d-1, loofa deformation and clogging after 72 days of application might be considered a serious shortcoming during use in full-scale applications. Nitrogen removal efficiency decreased from 85.6% at an organic loading rate of 0.6 kg m-3d-1 to 56.1% at an organic loading rate of 2.4 kg m-3d-1

Some biological characteristics of roach, Rutilus rutilus caspicus, in Gomishan wetland

This study was conducted to determine some biological characteristics of migration population of roach, rutilus caspius including age, growth and reproduction in Gomishan wetland from early November 1999 to early December 2000. The sampling were carried out monthly but in the peak of spawning period (late February to mid April) it was done weekly. The sex ratio was found M:F=1.17:1.00 without any significant difference (even at 10% level); but the results of the sex ratio for each separate age group showed significant difference (p< 0.05). A significant correlation was determined between total lengths, body weight, scale radius and age Based on back calculation, the maximum growth rate were found in ages 1+ and 2+ Gonadosmatic index (GSl) was age-dependent; with two peaks or late February and early March for males und late March and early April for females. The eggs diameter was measured with a range from 0.9 mm to 1.45 mm and the absolute fecundity was related to age

Ocean acidification and temperature increase impact mussel shell shape and thickness: Problematic for protection?

Ocean acidification threatens organisms that produce calcium carbonate shells by potentially generating an under-saturated carbonate environment. Resultant reduced calcification and growth, and subsequent dissolution of exoskeletons, would raise concerns over the ability of the shell to provide protection for the marine organism under ocean acidification and increased temperatures. We examined the impact of combined ocean acidification and temperature increase on shell formation of the economically important edible mussel Mytilus edulis. Shell growth and thickness along with a shell thickness index and shape analysis were determined. The ability of M. edulis to produce a functional protective shell after 9 months of experimental culture under ocean acidification and increasing temperatures (380, 550, 750, 1000 &mu;atm pCO2, and 750, 1000 &mu;atm pCO2 + 2&deg;C) was assessed. Mussel shells grown under ocean acidification conditions displayed significant reductions in shell aragonite thickness, shell thickness index, and changes to shell shape (750, 1000 &mu;atm pCO2) compared to those shells grown under ambient conditions (380 &mu;atm pCO2). Ocean acidification resulted in rounder, flatter mussel shells with thinner aragonite layers likely to be more vulnerable to fracture under changing environments and predation. The changes in shape presented here could present a compensatory mechanism to enhance protection against predators and changing environments under ocean acidification when mussels are unable to grow thicker shells. Here, we present the first assessment of mussel shell shape to determine implications for functional protection under ocean acidification. &copy; 2015 Published by John Wiley &amp; Sons Ltd

A field indoor air measurement of SARS-CoV-2 in the patient rooms of the largest hospital in Iran

The coronavirus disease 2019 (COVID-19) emerged in Wuhan city, China, in late 2019 and has rapidly spread throughout the world. The major route of transmission of SARS-CoV-2 is in contention, with the airborne route a likely transmission pathway for carrying the virus within indoor environments. Until now, there has been no evidence for detection of airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and this may have implication for the potential spread of the COVID-19. We investigated the air of patient rooms with confirmed COVID-19 in the largest hospital in Iran, on March 17, 2020. To collect the SARS-CoV-2 particles, ten air samples were collected into the sterile standard midget impingers containing 20 mL DMEM with 100 μg/mL streptomycin, 100 U/mL penicillin and 1 antifoam reagent for 1 h. Besides, indoor particle number concentrations, CO2, relative humidity and temperature were recorded throughout the sampling duration. Viral RNA was extracted from samples taken from the impingers and Reverse-Transcription PCR (RT-PCR) was applied to confirm the positivity of collected samples based on the virus genome sequence. Fortunately, in this study all air samples which were collected 2 to 5 m from the patients' beds with confirmed COVID-19 were negative. Despite we indicated that all air samples were negative, however, we suggest further in vivo experiments should be conducted using actual patient cough, sneeze and breath aerosols in order to show the possibility of generation of the airborne size carrier aerosols and the viability fraction of the embedded virus in those carrier aerosols. © 2020 Elsevier B.V