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Many advanced technologies have shown encouraging results in removing antibiotics from domestic wastewater. However, as activated sludge treatment is the most common sewage treatment system employed worldwide, improving its effect on antibiotic removal would be more desirable. Understanding the removal mechanisms, kinetics and factors that affect antibiotic removal in the activated sludge process is important as it would allow us to improve the treatment performance. Although these have been discussed in various literature covering different types of antibiotics and wastewater, a specific review on antibiotics and domestic wastewater is clearly missing. This review paper collates, discusses and analyses the removal of antibiotics from sewage in the activated sludge process along with the removal mechanisms and kinetics. The antibiotics are categorised into six classes: β-lactam, dihydrofolate reductase inhibitor, fluoroquinolone, macrolide, sulfonamides and tetracycline. Furthermore, the factors affecting the system performance with regard to antibiotic removal are examined.

Antibiotics are widely used in human society and are consequently found in sewage treatment plants. However, information regarding the fate of antibiotics in decentralised sewage treatment plants is limited. Therefore, this study monitored and compared four frequently prescribed antibiotics (ampicillin, ciprofloxacin, erythromycin and sulfamethoxazole) in each stage of four conventional treatment plants (three extended aerations and one conventional activated sludge) and two decentralised treatment plants (two Imhoff tanks) in Johor Bahru district between December 2018 and August 2019. The findings revealed that ampicillin, ciprofloxacin, erythromycin and sulfamethoxazole were detected in most wastewater samples, including influent, secondary effluent, final effluent and sewage sludge samples. The antibiotic concentrations in the aqueous and sludge phases ranged from 4.2 to 2690 ng/l and 1.7 to 317.4 ng/g, respectively. Ampicillin and sulfamethoxazole were effectively removed by extended aeration and conventional activated sludge plants (> 75% reduction), erythromycin was effectively removed in IT plants (> 85% reduction) and ciprofloxacin could not be removed effectively by any systems (

Membrane bioreactors (MBR) have gained much attention due to their ability to achieve higher treatment efficiency. However, high external energy consumption in aeration for membrane fouling mitigation has been limiting their application. Microbial fuel cells (MFC) can ideally extract energy from wastewater in the form of electricity and reduce membrane fouling. Thus, the use of MFC-MBR is rapidly expanding. However, the MFC-MBR design and operation is not fully mature and further research is needed to optimize the process efficiency and enhance the applicability. This review gives an overview of recent studies on the performances of MFC-MBR systems, regarding the design and configuration of the integrated system, irrespective of whether optimization was done or not in the operating system.

This paper appraised divergent chemical depolymerization routes for reprocessing chemically synthesis polyethylene terephthalate (PET) plastics bottle waste and offer resolutions to control the environmental complications emanating attributable to its utilize and disposal to the habitat. The consciousness to prune environs contaminants and make it “green” demand for the reclaim and reprocessing it back to PET bottles, precursor products like glycolyzate, and other inventions such as unsaturated polyester resins, epoxy resins, composites etc. Controlling this necessitates assorted reprocessing methods of which chemical recycling that transform PET into monomer/oligomer is the most prosperous one. This review explored in detail current events in the PET chemical recycling using glycolysis method. The study was based on their current evolution concerning their depolymerization agents, reaction conditions, kinetics of reactions, catalysts used, products of reprocessing, and their prospective use. Benefits of PET recycling and glycolysis as well as criteria and necessitation factors that used to adjudge them as the best method and sub-method respectively were highlighted. The prospect for the conversion of glycolyzate into other PET recycling methods products were shown. PET recycling was concluded to be a partial resolution to wastes management, and also grants the conservation of natural petrochemical resources and energy.

Haze pollution is one of the major environmental issues caused by aerosols, having brought about a history of heavy smog pollution events like the London smog in 1952 and the Los Angeles smog in the 1960s. However, in Malaysia, haze events are attributed to forest and peat fires in Kalimantan and Southern Sumatra, Indonesia. The burned biomass basically contains concentrated particulate matters that are hazardous to health among susceptible population groups. Based on the extensive literature review conducted, the small number of available local studies on the health effects of air pollution in Malaysia conducted so far focused on air pollution sciences. In this paper, a comprehensive overview of studies done on the impacts of haze on health conditions among populations in Malaysia is presented. The result shows that the number of upper respiratory tract infection cases was directly proportional to the particulate matter concentration and Air Pollution Index value in Johor in the years 2014 and 2015. Particulate matteris the major contributor in the formation of heavy hazes and is more likely to initiate detrimental health effects compared to other inhalable particles due to their size, large area, and strong activity, making them more likely to carry harmful substances causing a higher number of infected patients with upper respiratory tract infections.

Wastewater treatment systems have been designed to minimize the environmental impacts of discharging untreated wastewater in natural aquatic systems. Different wastewater treatment options have different performance characteristics and different direct impacts to the environment. The main aim of this study is to assess and quantify the environmental impacts of an electroless nickel plating wastewater treatment plant in Skudai, Johor Bahru, Malaysia. A life cycle assessment method, based on the international organization for standardization 14040 series framework, was used to assess the environmental impacts of the selected wastewater treatment plant. The ReCiPe life cycle impact assessment method attached to GaBi 4 software was used to assess the environmental impact of the selected industrial wastewater treatment plant. The results show that the existing chemical treatment process had the highest environmental impacts in terms of climate change with 1552.89 kg of CO2 and terrestrial acidification of 5.79 kg SO2 equivalent compared to the physical and biological treatment processes. Hence, two different scenarios, one utilizing chitosan and the other wet air oxidation (WAO) process, were formulated to reduce the environmental impacts of the conventional chemical wastewater treatment process. The impacts on the climate change using chitosan and WAO scenarios were both seen to have less than 110 kg CO2-equivalent emissions compared to the existing chemical process.

Life cycle assessment (LCA) is an analytical tool used to quantify the overall environmental impacts associated with products, processes or human activities from cradle to grave. The LCA is important to determine the impact of wastewater treatment and the technologies used on human health and the environment. It performs well to find the best solutions to improve the sustainability. Therefore, it is important to review how previous studies on wastewater treatment have applied LCA. This paper presents a wide-ranging review of papers published from 1990 to 2016 that have used a range of LCA to cover the objectives, boundaries, functional units (FUs) and life cycle impact assessment(LCIA) of wastewater treatment. The analysis of the reviewed papers revealed that there are some differences in term of the FUs, system boundaries, and LCIA methods. These differences normally contribute to obtaining a few non-prosaic results. Moreover, the FUs adopted in some reviewed studies were not able to achieve the purpose of providing a reference to ensure compatibility of the results. Therefore, it is highly recommended that more attention is paid to choosing the FU in future studies. Thus, to ensure the quality and comparability of LCAs, it is very important to develop the LCA guidelines and standards and the LCIA impact categories.

The world is experiencing high rates of urbanisation and it has slowly become an alarming social process, especially in developing countries. This has demanded an urgent investigation on human thermal comfort, especially in tropical climates. In this study, a surrogate human sensor (SHS) was developed to establish a linkage between human skin surface and SHS with the surrounding environments. Black plastic corrugated cardboard was used in the SHS fabrication as its thermal conductivity was close to the thermal conductivity and emissivity of the human epidermal skin layer. The SHS was designed to correlate with human skin surface temperature and a regression model was developed. The regression equation was obtained for the human skin temperature prediction (Th) by using SHS. Statistical analysis of the ANOVA (F = 13,700; ρ

The increased use of freshwater for domestic, industrial and agricultural activities has rapidly led to the scarcity of global water supplies with agricultural industry being the main consumer of fresh water, accounting to approximately 85% of the global freshwater consumption. Palm oil is the biggest and fastest growing vegetable oil on the world market and oil palm plantations are covering large land areas especially in Indonesia and Malaysia. Several environmental problems related to oil palm plantation have been reported, such as biodiversity loss, land use change, huge water consumption and river pollution. Water footprint analysis has been used to indicate the water consumption of a country, product, services or even an individual. However, methods to assess water usage in crude palm oil plantations is not available to date. Thus, this paper aims to provide a method in calculating water footprint for crude palm oil productions in Malaysia. The most appropriate method was identified based on an extensive literature survey. ISO 14046 was chosen as a guideline because it is an international standard in reporting and assessing water footprint (WF) with LCA approach. This study preferred the use of the comprehensive water footprint assessment compared to the stand-alone assessment because this approach can assess all the potential environmental impact related to water which are associated with a product, process or organization. It is expected that the water degradation level in this plantation can be identified to provide guidelines to the government, plantation companies as well as developers for the development of sustainable palm oil plantation in Malaysia.

River pollution from the agriculture industry has become an important cause of unscheduled water disruptions in Malaysia. Thus, rigorous control and treatment of high strength wastewater prior to discharge into the river are needed. This study aims at evaluating the performance of a pilot membrane bioreactor (MBR) for the treatment of palm oil mill effluent (POME). POME was subjected to MBR operating in an aerobic environment for 40 days, followed by 10 days without aeration and water pumping to simulate failure event, and finally resumed to operational condition. Higher proportions of protein (-PN) compared to polysaccharides (-PS) were present in both the mixed liquor and biofilm, indicating that protein was the main constituent of extracellular polymeric substances (EPS). Biological samples from the mixed liquor and biofilm on the membrane surfaces were collected on day 25, 50 and 75 to investigate taxonomic distribution of microbial community. High throughput sequencing of the 16S rRNA gene was used to investigate the composition of microbial communities in the MBR. Microbial groups such as the phyla Proteobacteria (19–23%), OD1 (11–15%), Chloroflexi (11–13%) were the dominant members in biofilm under operational condition while OD1 (20%), Proteobacteria (18%) and Planctomycetes (16%) were found to be dominant in biofilm under static and non-operational conditions. The taxonomic profile of the microbial community on day 75 is more similar to that of day 25, compared to day 50, suggesting the capability of the microbial communities to revert to the operational state despite a period of downtime.

The purpose of this paper is to propose an alternative methodology for aggregation in a life cycle assessment (LCA). The comprehensive aggregation method is based on a damage approach and done through an analytical hierarchy process. Consistency analysis is also presented to justify the reliability of the judgements and the magnitude of change in the values developed. A case study of electricity generation is applied to demonstrate its applicability in LCA study within a Malaysian context. Results from this case study show that the weighting value is higher compared to global and European values; however, they are consistent as in the case of product ranking towards greener products. Regional impacts such as particulate matter formation and photochemical oxidant formation have higher score compared to global impacts such as climate change. The results show that the method is simple and replicable.

The increasing concerns of water resource are becoming an important issue as severe shortage of water has been seen throughout the world. Though membrane bioreactor (MBR) has made an enormous progress and has become a promising approach in wastewater treatment, there are still several limitations on conventional MBR and thus there emerged integrated MBR for wastewater treatment technology. This paper aims to provide a consolidated review on the current state of research for the integrated MBR system with other technologies for wastewater treatment and help to sustain the treatment process itself. The areas for potential applications of various types of MBR are discussed in this review article. It is expected to provide future prospects to implement integrated MBR as a promising wastewater treatment technology. The valorization of wastewater in integrated MBR would reduce pollution and more importantly open a new source of energy and nutrients. Moreover the integrated MBR makes energy and nutrient recovery to be environmentally and economically feasible.

Extensive use of recalcitrant azo dyes in textile and paper industries poses a direct threat to the environment due to the carcinogenicity of their degradation products. The aim of this study was to investigate the efficiency of Curvularia clavata NZ2 in decolorization of azo dyes. The ability of the fungus to decolorize azo dyes can be evaluated as an important outcome as existing effluent treatment is unable to remove the dyes effectively. C. clavata has the ability to decolorize Reactive Black 5 (RB5), Acid Orange 7 (AO7), and Congo Red azo dyes, utilizing these as sole sources of carbon and nitrogen. Ultraviolet-visible (UV-vis) spectroscopy and Fourier infrared spectroscopy (FTIR) analysis of the extracted RB5's metabolites along with desorption tests confirmed that the decolorization process occurred due to degradation and not merely by adsorption. Enzyme activities of extracellular enzymes such as carboxymethylcellulase (CMCase), xylanase, laccase, and manganese peroxidase (MnP) were also detected during the decolorization process. Toxicity expressed as inhibition of germination was reduced significantly in fungal-treated azo dye solution when compared with the control. The cultivation of C. clavata under sequential batch system also recorded a decolorization efficiency of above 90%. The crude enzyme secreted by C. clavata also showed excellent ability to decolorize RB5 solutions with concentrations of 100 ppm (88-92%) and 1000 ppm (70-77%) without redox mediator. This proved that extracellular enzymes produced by C. clavata played a major role in decolorization of RB5.

Rapid urbanization has greatly impacted housing demand and housing development in Iskandar Malaysia, Johor. Iskandar Malaysia vision towards development of a low carbon society and in line with Malaysian government policy promoting industrialized building system (IBS) to meet the increasing housing demand. Hence, a comparative analysis of life cycle analysis (LCA) at assembly phase has been conducted to identify life cycle impact assessment and hotspot for material and construction stage between IBS and conventional cast in situ for residential apartment buildings in Iskandar Malaysia. The purpose is to apply IBS in residential building construction towards greener building and sustainable development. The functional unit of the comparison analyses was one square metre of produced building area for the respective construction period. A comparable inventory analysis will be carried out between two case studies. An input-output flowchart is created for each process to determine the components included in the analysis. Flows of assembly phase will be modelled in Gabi 6.0 software to further interpret the life cycle impact assessment (LCIA) between the two construction methods, and to determine the hotspot between the processes. Finally, a sensitivity analysis will be conducted to determine the influence of variations in assumptions, methods and data on the results.

© 2019 This study conducted a life cycle assessment of palm oil mill effluent (POME) based energy generation using the CML 2001 method and Gabi 8 software, focusing on two POME treatment technologies: the covered lagoon bio-digester (CLB) and the continuous stirred tank reactor (CSTR). The analysis determined the respective environmental impacts of the technologies, both of which are currently in use in Malaysia. The global warming potential (GWP) and acidification potential (AP) for CSTR were −4.48 kg CO2 eq/kWh and −2.21 kg SO2 eq/kWh respectively, while for CLB the values were −4.09 kg CO2 eq/kWh and −0.15 kg SO2 eq/kWh. Both technologies produced a negative result, which equates to a net environmental benefit. However, both systems had a negative impact in terms of eutrophication potential (EP). The CSTR nevertheless achieved a better EP result of 0.048 kg PO43− eq/kWh than the CLB with 0.054 kg PO43− eq/kWh. A sensitivity analysis was carried out in order to find a way to overcome the impacts of EP. The findings provide useful data to guide decision-makers in the sustainable management of POME, in Malaysia and globally where similar technologies are in use.

Purpose – The purpose of this paper is to compute the amount of methane generated from the waste of livestock from 1980 to 2008; then use the information in forecasting subsequent methane emissions by the sector in Malaysia from 2009 to 2020. Design/methodology/approach – The research study employed two approaches; computing methane emissions from 1980 to 2008 using the IPCC guidelines, and forecasting methane emissions for the animals from 2009 to 2020 using the autoregressive integrated moving average (ARIMA) model from the predictive analysis software (PASW-SPSS 18.0). Findings – Methane emissions from cattle, buffaloes and pigs accounted for over 95 per cent of total emissions and emissions from cattle are predicted to increase from 67.0 Gg in 2009 to 77.0 Gg by 2020. Emissions from the others will not be appreciable although poultry emissions will rise to 11.0 Gg by 2020. Attempt by the Malaysian Government to increase cattle production is not necessary at the moment as protein requirement has been met. Research limitations/implications – ARIMA model suffers from linear and data limitation: the future value of a variable assumed to be a linear function of several past observations in ARIMA is sometimes unrealistic. Large amounts of historical data are needed in ARIMA models in order to get desired results. The inventory of the animals was taken from 1980 to 2008.This needs to be improved upon by updating it to cover up to 2011 so that the forecast will start from 2012. Practical implications – The chosen ARIMA method has demonstrated its correctness in being adequate as a predicting tool for animal methane emissions. Policy makers can apply it so as to take practical steps to avoid these emissions. Originality/value – This is a novice idea as animal methane emission forecasting tool. This model will be of immense use and help in predicting methane emissions from livestock.

Malaysia has twice launched nationwide recycling campaign in 1993 and 2000. The result of the campaign to encourage household participation in recycling is inconclusive as the programs were concentrated only in urban areas. This study is an effort to conduct a comprehensive study on the effects of the recycling campaign and awareness on household recycling participation. A standard questionnaire survey was conducted on 460 households in selected residential areas that have active recycling programs in Kuala Lumpur Federal Territory (KLFT). The study identified the socio-economic characteristics of household recyclers and non-recyclers and their levels of knowledge on recycling by applying discriminant analysis. In addition, evaluation of the barriers and motivations of households performing recycling was investigated using factor analysis. The information was combined to form a profile of household recyclers and non-recyclers in urban Malaysia. Formulation was conducted on different recycling strategies and awareness campaigns at the household level to improve the existing recycling programs and facilities for the improvement of household participation. The study succeeded in forming a profile of household recyclers dominated by higher income earners with higher educational backgrounds, who owned houses and had deeper appreciation of recycling as a social norm. The non-recyclers had lower education and income, were tenants in one-storey houses, with little knowledge of recycling and its challenges. The study summarized the urgency for more strategic and targeted approach to recycling campaigns at the local level, taking into account the socio-economic backgrounds of the community, for more active participation in recycling at all levels.

The effect of recirculating the flue gas on the performance of a multi-cyclones unit as particulate collector in an actual plant scale was studied. The existing multi-cyclones unit was modified by connecting a recirculation duct between the inlet and outlet gas stream of the multi-cyclones attached with an external induced (ID) fan. The particulate samplings were done following the U.S. EPA method at boiler outlet (before multi-cyclones), stack (after multi-cyclones) and recirculation duct. Result shows that the amount of recirculated particulates increases with ID fan suction power. The collection efficiency increased slightly from 68% (0% or without recirculation) to 74% (at 11% recirculation) and dropped to 67% (at 17% recirculation). Moreover, the amount of the fine particulate size fraction emitted able to be reduced one fold at 11% recirculation flow rate. However, high amount of recirculated particulates results in re-entrainment of particulates into the outlet of the multi-cyclones, hence, results...

This paper reviewed the application of membrane bioreactor in treating high strength industrial wastewater by analysing operational parameters, limitations and mitigations of MBR for industrial wastewater. High strength industrial wastewater is difficult to classify but by its characteristics can be predicted using biodegradability criteria (BOD5/COD). Several factors need to be taken into consideration to find suitable operating parameters such as hydraulic retention time (HRT), solid retention time (SRT), mix liquor suspended solid (MLSS), food to microorganism (F/M), transmembrane pressure (TMP) and Flux (J) to obtain good quality effluent and reduce the fouling effect. Fouling factors by membrane, biomass and MBR operation need to be taken seriously because they are the major problems affecting the performance of the MBR and quality of the effluent. There are specific methods to reduce and clean the clogging membrane depending on the level of severity of the fouling. The mitigation covers physical cleaning such as membrane relaxing, backwashing, a combination of both and chemical cleaning which is used for irreversible fouling. In some cases, modification of MBR is needed to improve the performance and to achieve high quality of effluent.

A bench scale aerobic submerged membrane bioreactor (ASMBR) was used to treat diluted palm oil mill effluent (POME). For further improving the effluent quality and reduction of bio-fouling, powdered activated carbon (PAC) and zeolite were used as bio-fouling reducers (BFR). We compared the performances of ASMBR without BFR (called BFR0) with ASMBR using BFR, namely 2 g/L PAC (BFR1), 4 g/L PAC (BFR2) and 2 g/L zeolite (BFR3) for a period of about 70 days. Each system with BFR showed distinct performances by producing higher effluent quality as compared with BFR0. On average, the systems with and without BFR removed COD by 97.5–98.5% and 95.2%, respectively. The ASMBR with BFR also produced permeate with average residual color between 16 and 26 Pt-Co, as compared to 80 Pt-Co by BFR0. The addition of BFR increased the critical flux from 20 LMH (BFR0) to 36, 42 and 30 LMH (BFR1, BFR2, and BFR3). Furthermore, the ASMBR systems with BFR formed lower operational trans-membrane pressure (TMP), lowered the concentration of soluble microbial products (SMP) and increased the concentration of EPS.

Uncontrolled emission of greenhouse gases (GHGs) to the atmosphere leads to climate change. One of the key contributors in GHG emission is municipal solid waste. Increasing population and rapid urbanisation in Malaysia directly influence MSW generation that has increased from 5.6 million tonnes in 1997 to more than 8 million tonnes in 2010 with a projection of more than 9 million tonnes by 2020. There are 6 operational sanitary landfills out of the 104 in operation in Peninsular Malaysia with five of them recovering methane. With a biodegradable component of more than 60%, MSW landfills are potential sources of cheaper and cleaner landfill gas (LFG). 310,225 t of methane were emitted from the MSW landfills in 2010 with carbon credit potential of US$85.93 million and can yield 2.20×109 kW h of electricity valued at US$219.50 million. Emission projections were made for the years 2015 and 2020. The analysis points to a very promising and viable resource utilisation potential that will be of economic and environmental benefits. It will also create job opportunities for the local community. The use of this LFG will provide the means for overall GHG reductions and boost the efforts to achieve sustainable development.

The views of the public on solid waste bound to be generated in Johor Bahru Malaysia are presented and appraised. This is because of the massive development currently going on to transform the city to an international standing by the year 2025. For this reason, attempts to raise stakeholder awareness on the need to embrace on how best to manage the current problem with reduced impacts to the environment currently and in the future was attempted. Data were collected through contacts and questionnaire survey. Analytical hierarchy process (AHP) technique was used to structure and assess the views and judgments of stakeholders on the environmental impacts of solid waste disposal. SuperDecision software was used to generate and compute results of stakeholder's judgments. The assessment revealed that fauna and flora, habitat depletion and land use among the criteria are most critical environmental impacts. Landfilling, recycling, incineration and composting were evaluated in terms of the environmental impacts. The choice of incineration is perceived to improve environmental visibility, preserves fauna and flora as well as stream ecology, improves environmental air quality and optimizes land use. Similarly, recycling of waste, is perceived to preserves fauna and flora, stream ecology, habitat depletion, improves air quality as well as land use. Composting is perceived to be the best option in terms of preservation of stream ecology, habitat depletion and land use practice. Landfill generates less noise and vibration but found to be responsible for more than 50% of the environmental impacts created by solid waste in this area. Composting and recycling are mostly preferred to landfilling and incineration and the reason why this is so was provided. The study also identified challenges ahead and highlights that benefits attached to some vital disposal options (such as incineration) are yet to be fully implemented.

The problems posed by municipal solid waste in Asia are more complex because here, most nations urbanize rapidly with about 30–50% population increase. In developing countries, the growth rate of most cities exceeds 4% per annum. The issue at stake is that the 20–40% of municipal revenues spent in most countries to manage the waste is not enough to handle the rising trend of the waste generated. The problems are multi-dimensional. In Asia for example, issues ranging from disputes, norms, health concerns have continued to create obstacles and sometimes alarming situations. This had interfered with proper decisions in managing the waste that menaces the environment at a pace faster than the modern technology itself. In the paper some of the municipal solid waste management options are reviewed in some of these Asian countries with emphasis on a life cycle assessment (LCA) to adopt an integrated approach in solving the problem. Some solid waste management options were evaluated where some viable and suitable options could be derived based on Asian approach. Therefore, sustainable scenarios are suggested for stakeholders to manage municipal solid waste properly. The results are specifically intended to be used as a basis for decisions on strategies and policies for waste management and investments for new waste treatment facilities by decision makers in local, regional and national authorities or industries in the region.

This paper reviews the performance of MBR in treating high strength industrial wastewater. The scope covers the operation, constraints and mitigation of the system in general views. High strength wastewater can be successfully treated by using membrane bioreactor (MBR) in different conditions according to the types and characteristics of wastewater and also MBR parameters operational control. High strength wastewater contains fats, oil and grease or other organic or inorganic compounds in great amount according to the types of sources that take part. Several factors need to be taken into consideration during the operation such as hydraulic retention time (HRT), solid retention time (SRT), mix liquor suspended solid (MLSS), food to microorganism (F/M), transmembrane pressure (TMP) and flux. Fouling factors need to be taken seriously because they are the major problems affecting the performance of the MBR and quality of the effluent. There are specific methods to reduce and clean the clogging membrane depending on the level of severity of the fouling. Besides that, the performance of MBR in removing soluble organic waste can be increased by adding a fouling reducer such as powdered activated carbon (PAC).

This paper presents a study on the performance of an Aerobic Submerged u-shaped membrane bioreactor (ASMBR) in treating sulfidic spent caustic (SSC) in terms of mixed liquor suspended solid (MLSS) concentration and solid retention time (SRT). SSC wastewater is categorized as high strength wastewater and consists of high inorganic and organic matter. U-shape membrane bioreactors have a higher tendency to foul compared to other types of MBR. MLSS concentration and SRT are the major parameters when operating membrane bioreactor. In this study, COD removal recorded reduction of more than 95% for average MLSS concentration runs and 90% for SRTs runs. Meanwhile, sulfide was removed 99%, and formed up to 79% of sulfate. The biofouling for MLSS concentration and SRTs were observed through TMP rate change and TMP average performance, TMP trend and SMP and EPS trends. Biocake layer and biolayer deposited on membrane surface was found influenced by biomass, the inert particulate biomass products accumulating in the reactor.Chemical Engineering Research Bulletin 19(2017) 102-110

The use of recycled sewage sludge ash (SSA) in Portland cement and concrete has attracted a lot of global interest due the increase in sludge production and the limitation of land availability where it is used as a soil conditioner. These are in addition to rising environmental concerns. The major components of SSA are SiO2, CaO, Al2O3, Fe2O3, MgO and P2O5. These compounds, in theory, make SSA a good pozzolanic material because when finely ground, SSA is found to be cementitious. Thus it can be used as cement replacement in Portland cement and concrete. Some of the advantages include reduction in waste disposal costs, provision of excellent sustainable practices, conservation of the environment provision of partial solution to land limitation problem for landfill. Some of its disadvantages are in terms of pozzolanic activity and strength coupled with high water demand which could be solved by adequate modification and treatment. This paper reviews the various use of SSA and summarises the progress made in the development of SSA as a partial replacement for Portland cement and concrete.