No abstract

A wastewater treatment plant (WWTP) frequently encounters fluctuation in ammonium concentration or flow rate (Q), which may affect the stability of ammonium oxidizing bacteria (AOB). In this study, two continuous stirred tank reactors (CSTRs) were operated for 588 days and ammonium concentration was varied at various steady-state conditions. There was no inhibition observed in CSTR operation and AOB acclimated once at a certain ammonium concentration. Cells at an acclimated steady-state concentration (200 mgTAN/L from R(A) and 1000 mgTAN/L from R(B)) were extracted to perform a batch test at operating conditions, and self-inhibition behavior was observed in the batch reaction. In CSTR operation, the environmental ammonium concentration was varied and the specific oxygen uptake rate (SOUR) value was estimated from daily profile data and compared with batch reaction. In the CSTR operation as a substitute for self-inhibition, the SOUR was shifted towards the maximum specific oxygen uptake rate (SOURmax) and no self-inhibition was observed. For further justification of the CSTR’s stability, several total ammonium nitrogen (TAN) concentrations (range from ~−106 to ~+2550 mgTAN/L) were directly added to interrupt the stability of the process. As a substitute for any effect on the SOUR, the CSTRs were recovered back to the original stable steady-state conditions without varying the operational conditions.

The climate change is significantly evolving novel microbes in the environment. In addition, nanoscience is advancing promptly to provide environmentally friendly engineering solutions to detect these microbes (i.e., pathogenic bacteria and viruses) in blood and water. There is a need to develop smart and efficient nano-biosensor to detect the pathogens, Escherichia coli (ATCC 47076) in the drinking water to protect the public against the diseases like hemolytic uremic, gastroenteritis, and acute diarrheas. The immunomagnetic separation strategy enables detecting bacteria in water samples fast and efficiently. The developed sensor is capable for the detection targeted E. coli ATCC 46076 based on Stripping differential pulse voltammetry (SDPV) and Cyclic Voltammetry (CV) measurements with a dynamic linear range of 101 to 107 CFU ml−1. Functionalized magnetite metal-organic frameworks (MOFs) serve as a capture probe and Spectro-electrochemical label. The developed disposable electrode offers advantages such as large dynamic range, high sensitivity, high selectivity, and short analysis time (5 min). As for as we know, this is the first report to display the potential of the AuNPs and MOFs nanoparticles based dispersible electrode for the detection of targeted E. coli from water and blood.

Water is one of the most important natural resources and is widely used around the globe for various purposes. In fact, the agricultural sector consumes 70% of the world’s accessible water, of which about 60% is wasted. Thus, it needs to be managed scientifically and efficiently to maximize food production to meet the requirements of an ever-increasing population. There is a lack of information on water requirements of crops and irrigation scheduling concerning the Shaheed Benazirabad district, Pakistan. Thus, the present study was conducted to determine the irrigation water requirements (IWR) and irrigation scheduling for the major crops in the Shaheed Benazirabad district, Sindh, Pakistan, using agro-climatic data and the CROPWAT model. Agro-climatic data such as rainfall, maximum and minimum temperature, sunshine hours, humidity, and wind speed were obtained from the NASA website, CLIMWAT 2.0, and world weather However, data about studied crops and soils were obtained from FAO (Food and Agriculture Organization). Analysis revealed that the IWRs per irrigation round for the four major crops—sugarcane, banana, cotton, and wheat—were as 3108.0 mm, 1768.5 mm, 1655.7 mm, and 402.5 mm, respectively. It was observed the IWRs are more sensitive in the hot season because of high temperatures and low relative humidity, and vice versa in the cold season. The use of scientific tools such as CROPWAT is recommended to assess IWRs with a high degree of accuracy and to compute irrigation scheduling. Accordingly, the study results will be helpful for improving food production and supervision of water resources.

The world is facing an acute water shortage. The present irrigation techniques used in the Hyderabad district, Pakistan, are not demand-driven. The present study was carried out to determine the crop water requirement (CWR), irrigation water requirement (IWR), and irrigation scheduling for major crops grown in the Hyderabad district using the CROPWAT model based on climatic, soil, and crop data. The analysis revealed that the total CWR for the entire growing season for sugarcane, banana, cotton, and wheat were 3,127.0; 2,012.3; 1,073.5; and 418.9 mm, respectively. However, the IWR for sugarcane, banana, cotton, and wheat for the entire growing season was found to be 2,964.0; 1,966.7; 1,052.7; and 407.6 mm, respectively. However, the contribution of rainfall was 163.0, 45.6, 20.8, and 11.3 mm during sugarcane, banana, cotton, and wheat, respectively. The CWR and IWR were higher during the dry season due to high temperatures and low relative humidity. However, the IWR of each crop was low in the initial stage which increased with the growing stage until the peak at the full growth stage. The study recommends the use of CROPWAT to investigate the irrigation water requirements with accuracy.