Assessment of water, sanitation, and hygiene target and theoretical modeling to determine sanitation success in sub-Saharan Africa.

Accessing the status of clean drinking water, sanitation, and hygiene remains a challenge in sub-Saharan Africa (SSA). The current article contributes to the progress made by the WASH initiatives in ten SSA countries in eliminating open defecation by 2030, using theoretical data from 2017 to 2019. The authors used regression trend estimation to observe that rural and urban population growth had a statistically significant detrimental influence on the elimination of open defecation by 2030. According to the predicted data model, by 2030-2035, the urban population of SSA would be 65, 25, and 10 million in all the three categories of income groups. An increase in the number of modern pit users (C1) shows no improvement at the annual rate of change. The unimproved toilets and open-pit latrines (C2 and C3) show a linear growth rate, which expanded over time. Population growth, higher unemployment, and teen pregnancies contribute to this increase. Under current conditions, the curve of modern pit latrine users will increase linearly. Nigeria has the most significant number of spread pit latrine users, which has decreased linearly from 25 to 20% since 2017. It was evident that the power-law trend in Nigeria would increase the usage of unimproved pit latrines and open-pit latrines. Ghana had the highest rate (50%) of open-pit latrine users, while the data show that this situation remained stable (2001-2017). In the Democratic Rep. Congo, annual rates increased linearly from 25 to 33% (2000-2017), while Burundi was one of the countries in the region with the lowest number of open-pit latrine users, although the annual rate has increased from 6.13 to 11.75% since 2017 to 2019. Supplementary Information: The online version contains supplementary material available at 10.1007/s10668-022-02620-z.

Will the extraction of COVID-19 from wastewater help flatten the curve?

With the potentially fatal effect of COVID-19 and its devastating impact on economies worldwide, some environmental scientist has suggested the use of waste from household sewage to trace the movement of SARS-CoV-2, within a given country. However, this approach is not without challenges where developing countries lack proper and adequate hygiene and sanitation, resulting in widespread defecation. Limited scientific research has been done to determine how many times a recently infected person can defecate and the quantification of SARS-CoV-2 found in a single expel. On the other hand, there is no detailed research to specify where the heavy viral load of SARS-CoV-2 can be found in human excreta. In this paper, we present some obstacles that this approach could face in the absence of an intense lockdown in developing nations such as sub-Saharan countries. To achieve this, we identify some research needs that will strengthen our understanding of the transmission, occurrence, and persistence of SARS-CoV-2 in sewage and wastewater, including the life-span that depends on temperature. A methodology to follow in the process of identifying a hotspot on a small scale using some mathematical distributions, including the normal distribution, log-normal distribution, and the most complex one known as Blancmange function, was presented with some examples. Our investigation showed that this method might have some challenges, especially in developing countries (sub-Sahara countries) where open latrine usage is very high. Some recommendations we suggested to ensure the efficiency of such a method on a small scale. However, in general, it is essential to note the extraction/detection method will not help more than the testing method used all over the world to trace SARS-CoV-2 -19 in humans.

Facemasks simple but powerful weapons to protect against COVID-19 spread: Can they have sides effects?

In the last few months, the spread of COVID-19 among humans has caused serious damages around the globe letting many countries economically unstable. Results obtained from conducted research by epidemiologists and virologists showed that, COVID-19 is mainly spread from symptomatic individuals to others who are in close contact via respiratory droplets, mouth and nose, which are the primary mode of transmission. World health organization regulations to help stop the spread of this deadly virus, indicated that, it is compulsory to utilize respiratory protective devices such as facemasks in the public. Indeed, the use of these facemasks around the globe has helped reduce the spread of COVID-19. The primary aim of facemasks, is to avoid inhaling air that could contain droplets with COVID-19. We should note that, respiration process is the movement of oxygen from external atmosphere to the cells within tissue and the transport of carbon dioxide outside. However, the rebreathing of carbon dioxide using a facemask has not been taken into consideration. The hypercapnia (excess inhaled content of CO2) has been recognized to be related to symptoms of fatigue, discomfort, muscular weakness, headaches as well as drowsiness. Rebreathing of CO2 has been a key to concern regarding the use of a facemask. Rebreathing usually occur when an expired air that is rich in CO2 stays long than normal in the breathing space of the respirator after a breath. The increase of the arterial CO2 concentration leads to symptoms that are aforementioned. Studies have been conducted on facemask shortages and on the appropriate facemask required to reduce the spread of COVID-19; however no study has been conducted to assess the possible relationship between CO2 inhalation due to facemask, to determine and recommend which mask is appropriate in the reduction of the spread of the coronavirus while simultaneously avoid CO2 inhalation by the facemask users. In the current paper, we provided a literature review on the use of facemasks with the aim to determine which facemasks could be used to avoid re-inhaling rejected CO2. Additionally, we presented mathematical models depicting the transport of COVID-19 spread through wind with high speed. We considered first mathematical models for which the effect air-heterogeneity is neglected, such that air flow follows Markovian process with a retardation factor, these models considered two different scenarios, the speed of wind is constant and time-space dependent. Secondly, we assumed that the wind movement could follow different processes, including the power law process, fading memory process and a two-stage processes, these lead us to use differential operators with power law, exponential decay and the generalized Mittag-Leffler function with the aim to capture these processes. A numerical technique based on the Lagrange polynomial interpolation was used to solve some of these models numerically. The numerical solutions were coded in MATLAB software for simulations. The results obtained from the mathematical simulation showed that a wind with speed of 100 km/h could transport droplets as far as 300 m. The results obtained from these simulations together with those presented by other researchers lead us to conclude that, the wind could have helped spread COVID-19 in some places around the world, especially in coastal areas. Therefore, appropriate facemasks that could help avoid re-inhaling enough CO2 should be used every time one is in open air even when alone especially in windy environment.

Production, disposal, and efficient technique used in the separation of heavy metals from red meat abattoir wastewater.

The availability of clean water from the already scarce sources is threatened by continuous addition of contaminated industrial and of abattoir waste into watercourses globally. The aim of the current study was to reduce the amount of waste produced, to decrease pollution derived from discharge of effluent meat wastewater, and also to minimise environmental health risk. This was all achieved by successfully synthesising a natural biopolymer chitin chitin-chitosan derivative derived from crab shell waste. Characterisation of the chitin polymer using physicochemical properties like yield, ash content, degree of acetylation, solubility, intrinsic viscosity, and molecular weight indicated that crab shell waste was a good source of chitin. This polymer was later deacetylated to form chitosan and then cross-linked with s-methylbutylamine to form chitin-chitosan adsorbent. The effectiveness of the above-modified product in purifying meat wastewater was conducted by means of comparative testing using hydride gas atomic absorption spectroscopy. The results of the qualitative and quantitative analysis showed that chitosan cross-linked s-methylbutylamine was efficient in removing the following metal ions: Cu (II), Zn (II), Cr (II), Pb (II), and Cr (II). The highest removal percentage was Cr (IV) and Pb (II) (95.45 and 92.66%), while Zn (II) and Fe (II) were 87.32 and 67.48%. The lowest percentage recovery of 38.55% was observed for the metal Cr. From the current study, it was evident that the cross-linked can significantly reduce the metal concentration in meat wastewater before it is released in the aquatic environment. Therefore, properly permitted international waste disposal methods should be employed to reduce adverse effects on the receiving environment.