M. K. Amir Hashim

The dual roles of phycoremediation of wet market wastewater for nutrients and heavy metals removal and microalgae biomass production

Wastewater generated from fresh, vegetables and meat shops contains high concentrations of nutrients, COD, BOD and TSS. Therefore, the direct discharge of wet market wastewater into natural water may increase the pollution level. Wet market wastewater is rich with nutrients necessary for microalgae growth. Therefore, it represent a superlative environment for producing high quantity of microalgae biomass which have several applications in aquaculture, human nutrition and pharmaceutical industries. Phycoremediation is a process with high potential for the treatment wastewater and removal of nutrients and heavy metals as well as the production of microalgae biomass. However, the main challenges for the phycoremediation technology lie in the wastewater composition, microalgae species, and the competition process between the microalgae strain and the indigenous organisms as well as final utilization of biomass yield. The present review discusses the dual roles of phycoremediation for nutrients and heavy metals removal and microalgae biomass production. The microbiological aspects of phycoremediation, mechanism for heavy metals removal from wastewater, as well as factors affecting wastewater treatment are reviewed. It appears that phycoremediation plays an important role in the treatment of wastewater and production of microalgae biomass.

Reduction of microbial risk associated with greywater by disinfection processes for irrigation

Greywater is one of the most important alternative sources for irrigation in arid and semi-arid countries. However, the health risk associated with the microbial contents of these waters limits their utilization. Many techniques have been developed and used to generate a high microbiological quality of greywater. The main problem in the treatment of greywater lies in the nature of pathogenic bacteria in terms of their ability to survive during/after the treatment process. The present review focused on the health risk associated with the presence of pathogenic bacteria in greywater and the treatment technologies used for the disinfection processes.

An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

Microalgae have high nutritional values for aquatic organisms compared to fish meal, because microalgae cells are rich in proteins, lipids, and carbohydrates. However, the high cost for the commercial production of microalgae biomass using fresh water or artificial media limits its use as fish feed. Few studies have investigated the potential of wet market wastewater and slaughterhouse wastewater for the production of microalgae biomass. Hence, this study aims to highlight the potential of these types of wastewater as an alternative superior medium for microalgae biomass as they contain high levels of nutrients required for microalgae growth. This paper focuses on the benefits of microalgae biomass produced during the phycoremediation of wet market wastewater and slaughterhouse wastewater as fish feed. The extraction techniques for lipids and proteins as well as the studies conducted on the use of microalgae biomass as fish feed were reviewed. The results showed that microalgae biomass can be used as fish feed due to feed utilisation efficiency, physiological activity, increased resistance for several diseases, improved stress response, and improved protein retention.

Treatment of Domestic Gray Water by Multicomponent Filters

This review described, summarized, evaluated, and clarified the related theories and previous research relevant to bathroom gray water quality and its design treatment system to reduce the contamination of gray water. It provides a theoretical base for research and helps in determining the nature of the research. In addition, this chapter may also serve as a handy guide on the use of ceramic filtration for bathroom gray water.

Removal of Pharmaceutically Active Compounds from Contaminated Water and Wastewater Using Biochar as Low-Cost Adsorbents, An Overview

Pharmaceutically active compounds (PhACs) have received high attention during the last few years due to their ability to persist for long time in the environment as well as their role in increasing the antimicrobial resistance among the floral bacteria in the nature. Many of the technologies have been investigated and applied to remove those compounds from the contaminated water and wastewater. The most common technology depends on the oxidation process which leads to degrade these compounds to be in inactive form. However, the oxidation process has some challenges which lie in the presence of secondary products and toxic by-products. The adsorption process is the best alternative technology where no energy is required and no toxic by-products are generated, and the process leads to separate the pollutants from the water and wastewater. In this chapter, the adsorption of PhACs by low-cost materials such as biochar and microorganisms is discussed.

A review of potential factors contributing to epidemic cholera in Yemen

The menace of cholera epidemic occurrence in Yemen was reported in early 2017. Recent reports revealed that an estimated 500,000 people are infected with cholera whereas 2,000 deaths have been reported in Yemen. Cholera is transmitted through contaminated water and food. Yemen is the least developed country among the Middle East countries in terms of wastewater and solid waste management. The population of Yemen is about 24.5 million and generates about 70-100 million m3 of sewage. An estimated 7% of the population has sewerage systems. It has been revealed that 31.2 million m3 of untreated sewage is used for irrigation purposes especially for vegetables and Khat trees. In addition, more than 70% of the population in Yemen has no potable water. They depend on water wells as a water source which are located close to sewage disposal sites. The present review focuses on the current status of water, wastewater as well as solid waste management in Yemen and their roles in the outbreak of cholera. Future prospects for waste management have been proposed.

Potential of Staphylococcus xylosus strain for recovering nickel ions from aqueous solutions

The potential of bacterial biomass for the biosorption of heavy metals has investigated extensively. However, the bacterial species exhibited different affinities toward the heavy metals ions based on their differences in cell wall characteristics, structure and physiological status (living or dead cells). In this study, the potential of living and dead cells of Staphylococcus xylosus 222W for removal nickel ions from aqueous solution as a function for physiological status, nickel and biomass concentrations, time, pH and temperature was investigated. The pre-treatment of bacterial cells was performed by the heating at 100 oC for 15 min. The removal experiments were conducted in the lab scale. The results revealed that the dead cells exhibited more efficiency in removing nickel ions than living cells at all investigated concentrations (2 to 10 mM). The biosorption efficiency (E %) increased with increasing in biomass cells to limit concentrations (0.1 to 1 g dry wt L-1). The maximum removal of nickel was 81.41 vs. 77.10 % by living and dead cells, respectively achieved after 9 and 10 hrs of the incubation period, respectively. The acidic conditions decrease the efficiency of metal removal, while the optimal removal was recorded at pH 8 for both biomass (living and dead cells). The maximum uptake capacity of S. xylosus 222W (living and dead cells) was recorded at 37oC, the percentage removed being 75.90 vs. 84.92 %, respectively. It can be concluded that S. xylosus 222W exhibited high potential and affinity to remove of nickel ions from aqueous solution.

Bio-removal of Nickel ions by Sporosarcina pasteurii and Bacillus megaterium, A Comparative Study

The aim of this work was to study the potential of Sporosarcina pasteurii 586S and Bacillus megaterium 1295S isolated from sewage treatment plants (STPs) in removing of nickel ions from the aqueous solution. The bacterial cells were used as living and dead cell biomass. The efficiency of bio-removal process was investigated as a response for nickel and biomass concentrations, time, pH and temperature. The bio-removal capacity (Qmax) of both strains were compared. The highest bio-removal percentage was recorded by dead cells in comparison to living cells. Dead cell biomass of B. megaterium 1295S exhibited higher efficiency for bio-removing of Ni2+ than S. pasteurii 586S at196.4 and 200.2 mg Ni2+ g-1, respectively. It can be concluded that both bacterial strains have high potential to be applied in the biotechnology for removing of Ni2+ ions, however, dead cells of B. megaterium 1295S is the most potent.