- Comparison between the coagulants surfactant modified bentonite,
combination chitosan-natural bentonite and combination chitosan-modified
bentonite for peat water treatment
- Authors: Nor Farhana Zakaria Siti; S. Syafalni Qamaruz Zaman Nastaein
Abstract: Peat water is an abundant water resource in Asia, especially in rural areas. However, it is unsuitable to be used as a commercial water supply. Monitoring peat water characteristics at Beriah swamp, Perak, recorded colour (238 PtCo), turbidity (12.86 NTU), iron (0.89 mg/L), pH (4.8) and chemical oxygen demand (COD) (27 mg/L) over the national limitation standards. In this study, surfactant modified bentonite (SMB) shows high removal of colour (95%), turbidity (97%) and iron (100%) from peat water, but not COD (almost non-removal). From the results obtained, treatment of peat water using a combination of chitosan-natural bentonite was more efficient by the resulting optimal removal for all parameters such as colour (78%), turbidity (89%), iron (90%) and COD (67%). Meanwhile, a combination of chitosan-SMB gave similar results as SMB alone; however, reducing the amount of pollutants used in combination was advantageous in this combination. The response surface method was applied and the optimal reaction between coagulant and sample due to pH, dosage and contact time was determined.
- Opportunities and challenges for greywater treatment and reuse in
Mongolia: lessons learnt from piloted systems
- Authors: Sayed Mohammad Nazim Uddin; Zifu Li, Heinz-Peter Mang, André Schüßler, Tobias Ulbrich, Elisabeth Maria Huba, Eric Rheinstein Jean Lapegue
Abstract: In Mongolia, as worldwide, communities are challenged by water scarcity, depletion and pollution. Greywater treatment and reuse could partially meet water demand and help protect the environment and health. In March 2010, greywater from six randomly sampled households in the Ger areas of Ulaanbaatar, Mongolia, was analyzed followed by the development of three innovative treatment systems: an underground (UG-), greenhouse (GH-) and ice-hole greywater treatment unit (IH-GWTU). The UG- and GH-GWTU were implemented to identify opportunities and challenges for future investments in greywater treatment and reuse. Users' and non-users' perceptions, and business opportunities, were assessed. Laboratory analysis showed a high chemical oxygen demand (6,072–12,144 mg/l), N-NH4
+ (183.7–322.6 mg/l), PO4
− (12.6–88.2 mg/l) and total suspended solids (880–3,200 mg/l) – values exceeding the WHO guidelines and much higher than in any other country: low water consumption combined with traditional diet might be major reasons. Odourless and colourless water after treatment in a UG-GWTU lead to more acceptance than a GH-GWTU. Business opportunities include the use of treated water for irrigation, considering WHO and national standards. Further research focuses on seasonality of installation, technical shortcomings, maintenance, biological quality control and user training.
- Green Village Delft – integration of an autarkic water supply in a
local sustainable energy system
- Authors: J. P. van der Hoek; J. L. Izar Tenorio, C. Hellinga, J. B. van Lier A. J. M. van Wijk
Abstract: For the Green Village at the campus of Delft University of Technology, an autarkic water circuit was developed. The aim was to avoid connections to the public water supply system, the sewerage, the electricity grid and cable systems. It should produce its own drinking water and electricity, and clean its organic waste streams in a sustainable way. Due to the strict Dutch drinking water regulations, only one water quality will be supplied: drinking water. Drinking water will be produced from greywater (53%) supplemented with rainwater (47%). In the treatment scheme, the multiple barrier approach will be used to comply with the Dutch drinking water quality standards. For greywater treatment, a triple barrier is suggested: ozonation – ultrafiltration – UV disinfection. For rainwater treatment a dual barrier is suggested: ultrafiltration – UV disinfection. By separating wastewater streams at the point of origin into greywater and blackwater, and by replacing conventional toilets with low water consumption vacuum systems as part of the water conservation measures, it will be possible to collect a concentrated blackwater stream suitable for recovery energy. For this purpose the upflow anaerobic sludge blanket reactor is suggested. The proposed water circuit results in an autarkic water management, but not in an autarkic energy management.
- Comparison of behaviour and fate of tetrabromobisphenol A (TBBPA) in
membrane bioreactors and conventional activated sludge process
- Authors: Mohammad Showkatul Islam; Hongde Zhou Richard G. Zytner
Abstract: Research was completed on the behaviour and fate of tetrabromobisphenol A (TBBPA) in pilot-scale membrane bioreactors and conventional activated sludge (CAS) process at the City of Guelph Wastewater Treatment Plant. Emphasis was on the physicochemical processes, biological transformation and sorption kinetics. Measurement of TBBPA at the environmental level can be challenging, so the main focus of this paper was the development of an analytical method for the nano-level determination of TBBPA. The approach used was gas chromatography-negative ion chemical ionization-mass spectrometry in select ion monitoring mode. For the wastewater matrix studied, the developed method had a low method detection level (MDL) of 2.4 ng/L. The matrix effects for influent and activated sludge mixed liquor were determined to be 36.5 ± 5.9% (n = 10) and 79.2 ± 4.5% (n = 10), respectively. Preliminary results show that the CAS system demonstrates better performance for TBBPA removal, with removal at 83%. This was corroborated by the batch experiments that showed that the synergistic effects of biodegradation and biosorption potentially provide more removal of the TBBPA through the activated sludge process.
- Development of permeability properties of polyamide thin film composite
nanofiltration membrane by using the dimethyl sulfoxide additive
- Authors: Ahmad Akbari; Sayed Majid Mojallali Rostami
Abstract: A novel polyamide thin film composite (PATFC) as a nanofiltration (NF) membrane was prepared by a modified interfacial polymerization (IP) reaction. Herein trimesoyl chloride and piperazine as the reagents, dimethyl sulfoxide (DMSO) as additive and polysulfone (PSF) ultrafiltration membrane as support were used respectively. The main goal of the present study is to improve TFC membrane water flux by addition of DMSO into the aqueous phase of IP reaction, without considerable rejection loss. Morphological, roughness, and chemical structures of the PATFC membrane were analyzed by scanning electron microscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FT-IR), respectively. The AFM analysis demonstrated that as DMSO was added to the aqueous phase, the surface roughness of PATFC membrane increased. Results showed that the pure water flux of modified-PATFC membranes increased up to 46%, compared to nonmodified-PATFC membrane, while salt rejection was not sacrificed considerably. The results elucidated that the addition of DMSO leads to an increase in the number of cross-linking bonds between monomers and pore diameter, which results in enhancement of the membrane flux. Finally, the results showed that the newly developed PATFC membrane is a high-performance NF membrane which augments the efficiency of conventional PATFC membrane.
- Synthetic organic polymer fouling in municipal wastewater reuse reverse
- Authors: Y. Ekowati; M. Msuya, S. G. Salinas Rodriguez, G. Veenendaal, J. C. Schippers M. D. Kennedy
Abstract: A full scale waste water reuse plant suffered from irreversible fouling of the reverse osmosis (RO) membranes. The major suspect of fouling is cationic organic polymers applied in the wastewater sludge treatment. Thus, the purpose of this research is to study the effect of six cationic polymers, applied in the plant, on RO membrane performance. The filtration and adsorption experiments with 4 mg C/L polymer solutions were performed in laboratory RO set ups for 5–7 days. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to analyze polymers. Fouling prediction was calculated with Modified Fouling Index-ultrafiltration (MFI-UF) constant flux values. A flux decline of 30–50% was observed after filtration experiments. In adsorption experiments, the resistance increased from 6 to 35%. The MFI-UF results showed the rate of fouling was around 1 bar/month. The base-acid cleaning was able to reduce the resistance of the fouled membrane with irreversible fouling resistance, 6–7%. SEM images showed that the fouling layer after cleaning did not appear in the membrane. The FTIR spectra of the membrane after cleaning were similar to virgin membrane. However, several adsorption peaks on the membrane after cleaning were not restored to the initial state.
- A simulation impact evaluation of social-economic development on water
- Authors: Wenyi Wang; Weihua Zeng, Bo Yao Jing Wei
Abstract: Due to the fast growth of the economy and population, the water scarcity issue has aroused widespread critical concern. In fact, reasonable structure, adaptive patterns and effective regulation of the economy, society and water resources can bring a harmonious future. Therefore, the study of how to balance economic social growth and water resources is of great importance. A model of the water resource, society and economy system of the Tongzhou district was designed by Stella. The model established here attempts to analyze future trends in social-economic development and the impact of the economic and population growth on water use in the Tongzhou district under three scenarios. The results reveal that the water shortage is very serious. If the current trends persist, the existing water supply will not be able to meet the water demand in the future. Tongzhou district's water shortage will be 162.50 million m3 in 2020 under the business-as-usual scenario. Therefore, it is necessary to develop unconventional water sources and improve the water-saving capacity of production and life to alleviate the water tensions. This research offers insight into larger questions regarding economic growth and water resource management in general.