The option of reusing greywater is proving to be increasingly attractive to address the water shortage issue in many arid and semiarid countries. Greywater represents a constant resource, since an approximately constant amount of greywater is generated from kitchen, laundries, bathroom in every household daily, independent of the weather. However, the use of greywater for irrigation in particular for household gardening may pose major hazards that have not been studied thoroughly. In this study, a 1-year monitoring was conducted in four selected households in Perth, Western Australia. The aim of the monitoring works is to investigate the variability in the greywater flow and quality, and to understand its impact in the surrounding environments. Case studies were selected based on different family structure including number, ages of the occupants, and greywater system they used. Samples of greywater effluent (showers, laundries, bathtub, and sinks), leachate, soil, and plants at each case study were collected between October 2008 and December 2009 which covered the high (spring/summer) and low (autumn/winter) production of greywater. Physical and chemical tests were based on the literature and expected components of laundry and bathroom greywater particularly on greywater components likely to have detrimental impacts on soils, plants, and other water bodies. Monitoring results showed the greywater quality values for BOD, TSS, and pH which sometimes fell outside the range as stipulated in the guidelines. The soil analyses results showed that salinity, SAR, and the organic content of the soil increased as a function of time and affected the plant growth. Nutrient leaching or losses from soil irrigated with greywater shows the movement of nutrients and the sole impact from greywater in uncontrolled plots in case studies is difficult to predicted due to the influence of land dynamics and activities. Investigative and research monitoring was used to understand greywater irrigation in households. Greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater. Investigative and research monitoring was indicated that greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater.
This paper discusses the comparative assessment of eight candidate distributions in providing accurate and reliable maximum rainfall estimates for Malaysia. The models considered were the Gamma, Generalised Normal, Generalised Pareto, Generalised Extreme Value, Gumbel, Log Pearson Type III, Pearson Type III and Wakeby. Annual maximum rainfall series for one-hour resolution from a network of seventeen automatic gauging stations located throughout Peninsular Malaysia were selected for this study. The length of rainfall records varies from twenty-three to twenty-eight years. Model parameters were estimated using the L-moment method. The quantitative assessment of the descriptive ability of each model was based on the Probability Plot Correlation Coefficient test combined with root mean squared error, relative root mean squared error and maximum absolute deviation. Bootstrap resampling was employed to investigate the extrapolative ability of each distribution. On the basis of these comparisons, it can be concluded that the GEV distribution is the most appropriate distribution for describing the annual maximum rainfall series in Malaysia.
The inactivation of antibiotic resistant Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) seeded in greywater by bimetallic bio-nanoparticles was optimized by using response surface methodology (RSM). The bimetallic nanoparticles (Cu/Zn NPs) were synthesized in secondary metabolite of a novel fungal strain identified as Aspergillus iizukae EAN605 grown in pumpkin medium. Cu/Zn NPs were very effective for inhibiting growth of E. coli and S. aureus. The maximum inactivation was optimized with 0.028 mg mL-1 of Cu/Zn NPs, at pH 6 and after 60 min, at which the reduction of E. coli and S. aureus was 5.6 vs. 5.3 and 5.2 vs. 5.4 log reduction for actual and predicted values, respectively. The inactivation mechanism was described based on the analysis of untreated and treated bacterial cells by Field emission scanning electron microscopy (FESEM), Energy Dispersive X-Ray Spectroscopy (EDS), Atomic Force Microscopy (AFM) revealed a damage in the cell wall structure due to the effect of Cu/Zn NPs. Moreover, the Raman Spectroscopy showed that the Cu/Zn NPs led to degradation of carbohydrates and amino structures on the bacteria cell wall. The Fourier transform infrared spectroscopy (FTIR) analysis confirmed that the destruction take place in the C-C bond of the functional groups available in the bacterial cell wall. The techno economic analysis revealed that the biosynthesis Cu/Zn NPs is economically feasible. These findings demonstrated that Cu/Zn NPs can effectively inhibit pathogenic bacteria in the greywater.
Biodegradation of pharmaceuticals active compounds (PACs) in secondary effluents by using B. subtilis 2012WTNC as a function of β-lactamase was optimized using response surface methodology (RSM) designed by central composite design (CCD). Four factors including initial concentration of bacteria (1-6 log10 CFU mL-1), incubation period (1-14 days), incubation temperature (20-40 °C) and initial concentration of PACs (1-5 mg L-1) were investigated. The optimal operating factors for biodegradation process determined using response surface methodology (RSM) was recorded with 5.57 log10 CFU mL-1 of B. subtilis, for 10.38 days, at 36.62 °C and with 4.14 mg L-1 of (cephalexin/amoxicillin) with R2 coefficient of 0.99. The biodegradation was 83.81 and 93.94% respectively. The relationship among the independent variables was significant (p
The present study deals with optimizing, producing, characterizing, application and techno- economic analysis of oxidative enzymes [Laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP)] from Aspergillus iizukae EAN605 in submerged fermentation process using pumpkin peels as a production substrate. The best operating parameters for producing Lac, MnP and LiP (6.15, 2.58 and 127.99 U mg-1 respectively) were recorded with 20 g 100 mL-1 of substrate, 4.6 mL 100 mL-1 of inoculum size at pH 5.5 after 10 days. The crude enzyme exhibited high stability at pH (3-9) and temperatures (20-60 °C). Km (Michaelis-Menten) of Lac, MnP and LiP crude enzyme was 2.25, 1.79 and 0.72 mM respectively. The decolourization of Remazol Brilliant Blue R by the crude enzyme was 84.84 %. The techno-economic analysis was assessed for a production unit with an annual operating time for enzymatic production and application is 7920 h/year and 100 m3 of the capacity. The process would produce 27,000 cm3 of crude enzyme with a price of USD 0.107 per cm3 compared to USD 1 per cm3 of the current commercial enzyme. The findings indicated that pumpkin peels have potential as a production substrate for oxidative enzymes from A. iizukae EAN605 and is economically feasible.