Progress and challenges of contaminate removal from wastewater using microalgae biomass.

The utilization of microalgae in treating wastewater has been an emerging topic focussed on finding an economically sustainable and environmentally friendly approach to treating wastewater. Over the last several years, different types of con microalgae and bacteria consortia have been experimented with to explore their potential in effectively treating wastewater from different sources. The basic features considered while determining efficiency is their capacity to remove nutrients including nitrogen (N) and phosphorus (P) and heavy metals like arsenic (As), lead (Pb), and copper (Cu). This paper reviews the efficiency of microalgae as an approach to treating wastewater from different sources and compares conventional and microalgae-based treatment systems. The paper also discusses the characteristics of wastewater, conventional methods of wastewater treatment that have been used so far, and the technological mechanisms for removing nutrients and heavy metals from contaminated water. Microalgae can successfully eliminate the suspended nutrients and have been reported to successfully remove N, P, and heavy metals by up to 99.6 %, 100 %, and 13%-100 % from different types of wastewater. However, although a microalgae-based wastewater treatment system offers some benefits, it also presents some challenges as outlined in the last section of this paper. Performance in eliminating nutrients from wastewater is affected by different parameters such as temperature, biomass productivity, osmotic ability, pH, O2 concentration. Therefore, the conducting of pilot-scale studies and exploration of the complexities of contaminants under complex environmental conditions is recommended.

Measuring Oxygen Access: lessons from health facility assessments in Nigeria

The COVID-19 pandemic has highlighted global oxygen system deficiencies and revealed gaps in how we understand and measure "oxygen access". We present a case study on oxygen access from 58 health facilities in Lagos state, Nigeria. We found large differences in oxygen access between facilities (primary vs secondary, government vs private) and describe four key domains to consider when measuring oxygen access. Use8/58 (14%) of facilities had a functional pulse oximeter for detecting hypoxaemia (low blood oxygen level) and guiding oxygen care. Oximeters were typically located in outpatient clinics (12/27, 44%), paediatric ward (6/27, 22%), or operating theatre (4/27, 15%), not suitable for children, and infrequently used. Availability34/58 (59%) facilities had a functional source of oxygen available on the day of inspection, of which 31 (91%) facilities had it available in a single ward area, typically the operating theatre or maternity ward. CostOxygen was free to patients at primary health centres, when available, but expensive in hospitals and private facilities, with the median cost for 2 days oxygen 13000 ($36 USD) and 27500 ($77 USD) naira, respectively. Patient accessNo facilities were adequately equipped to meet minimum oxygen demands for patients. We were unable to determine the proportion of hypoxaemic patients who received oxygen therapy with available data. We highlight the importance of a multi-faceted approach to measuring oxygen access that assesses access at the point-of-care, and ideally at the patient-level. We propose standard metrics to report oxygen access and describe how these can be integrated into routine health information systems and existing health facility assessment tools. SUMMARY BOXO_LIOxygen access is poorly understood and the most commonly used metrics (e.g. presence of an oxygen source) do not correlate well with actual access to patients. C_LIO_LIPulse oximetry use is a critical indicator for the quality of oxygen services and may be a reasonable reflection of oxygen coverage to patients with hypoxaemia. C_LIO_LIOxygen, and pulse oximeter, availability must be assessed at the point-of-care in all major service delivery areas, as intra-facility oxygen distribution is highly inequitable. C_LIO_LIMinimum functional requirements for oxygen sources must be assessed, as many oxygen concentrators and cylinders may be present without being in working order. C_LI