Abstract: Comparing other methods of waste water treatment,
constructed wetlands are one of the most fascinating practices
because being a natural process they are eco-friendly have low
construction and maintenance cost and have considerable capability
of wastewater treatment. The current research was focused mainly on
comparison of Ranunculus muricatus and Typha latifolia as wetland
plants for domestic wastewater treatment by designing and
constructing efficient pilot scale horizontal subsurface flow
mesocosms. Parameters like chemical oxygen demand, biological
oxygen demand, phosphates, sulphates, nitrites, nitrates, and
pathogenic indicator microbes were studied continuously with
successive treatments. Treatment efficiency of the system increases
with passage of time and with increase in temperature. Efficiency of
T. latifolia planted setups in open environment was fairly good for
parameters like COD and BOD5 which was showing reduction up to
82.5% for COD and 82.6% for BOD5 while DO was increased up to
125%. Efficiency of R. muricatus vegetated setup was also good but
lowers than that of T. latifolia planted showing 80.95% removal of
COD and BOD5. Ranunculus muricatus was found effective in
reducing bacterial count in wastewater. Both macrophytes were
found promising in wastewater treatment.
Abstract: Polysulfone (PSU) is a specialty engineering polymer
having various industrial applications. PSU is especially used in
waste water treatment membranes due to its good mechanical
properties, structural and chemical stability. But it is a hydrophobic
material and therefore its surface aim to pollute easily. In order to
resolve this problem and extend the properties of membrane, PSU
surface is rendered hydrophilic by addition of the sepiolite
nanofibers. Sepiolite is one of the natural clays, which is a hydrate
magnesium silicate fiber, also one of the well known layered clays of
the montmorillonites where has several unique channels and pores
within. It has also moisture durability, strength and low price.
Sepiolite channels give great capacity of absorption and good surface
properties. In this study, nanocomposites of commercial PSU and
Sepiolite were prepared by solvent mixing method. Different organic
solvents and their mixtures were used. Rheological characteristics of
PSU-Sepiolite solvent mixtures were analyzed, the solubility of
nanocomposite content in those mixtures were studied.
Abstract: The rate of natural gas dissociation from the Coal
Matrix depends on depressurization of reservoir through removing of
the cleat water from the coal seam. These waters are similar to brine
and aged of very long years. For improving the connectivity through
fracking /fracturing, high pressure liquids are pumped off inside the
coal body. A significant quantity of accumulated water, a combined
mixture of cleat water and fracking fluids (back flow water) is
pumped out through gas well. In Queensland, Australia Coal Seam
Gas (CSG) industry is in booming state and estimated of 30,000 wells
would be active for CSG production forecasting life span of 30 years.
Integrated water management along with water softening programs is
practiced for subsequent treatment and later on discharge to nearby
surface water catchment. Water treatment is an important part of the
CSG industry. A case study on a CSG site and review on the test
results are discussed for assessing the Standards & Practices for
management of CSG by-product water and their subsequent disposal
activities. This study was directed toward (i) water management and
softening process in Spring Gully CSG field, (ii) Comparative
analysis on experimental study and standards and (iii) Disposal of the
treated water. This study also aimed for alternative usages and their
impact on vegetation, living species as well as long term effects.
Abstract: This study was conducted to evaluate the manganese
removal from aqueous solution using Banana peels activated carbon
(BPAC). Batch experiments have been carried out to determine the
influence of parameters such as pH, biosorbent dose, initial metal ion
concentrations and contact times on the biosorption process. From
these investigations, a significant increase in percentage removal of
manganese 97.4% is observed at pH value 5.0, biosorbent dose 0.8 g,
initial concentration 20 ppm, temperature 25 ± 2°C, stirring rate 200
rpm and contact time 2h. The equilibrium concentration and the
adsorption capacity at equilibrium of the experimental results were
fitted to the Langmuir and Freundlich isotherm models; the Langmuir
isotherm was found to well represent the measured adsorption data
implying BPAC had heterogeneous surface. A raw groundwater
samples were collected from Baharmos groundwater treatment plant
network at Embaba and Manshiet Elkanater City/District-Giza,
Egypt, for treatment at the best conditions that reached at first phase
by BPAC. The treatment with BPAC could reduce iron and
manganese value of raw groundwater by 91.4% and 97.1%,
respectively and the effect of the treatment process on the
microbiological properties of groundwater sample showed decrease
of total bacterial count either at 22°C or at 37°C to 85.7% and 82.4%,
respectively. Also, BPAC was characterized using SEM and FTIR
spectroscopy.
Abstract: This paper presents the application of finite dynamic
programming, specifically the "Markov Chain" model, as part of the
decision making process of a company in the cosmetics sector located
in the vicinity of Bogota DC. The objective of this process was to
decide whether the company should completely reconstruct its
wastewater treatment plant or instead optimize the plant through the
addition of equipment. The goal of both of these options was to make
the required improvements in order to comply with parameters
established by national legislation regarding the treatment of waste
before it is released into the environment. This technique will allow
the company to select the best option and implement a solution for
the processing of waste to minimize environmental damage and the
acquisition and implementation costs.
Abstract: This research aimed to study on the efficiency of wastewater treatment by comparing the different aeration times of surface aerators in Suan Sunandha Rajabhat University. In doing so, the operation of surface aerators was divided into 2 groups which included the groups of 8 hours (8-0/opened-closed) and 4 hours (2-2/opened-closed) of aeration time per day. As a result of the study, it was found that the efficiency of wastewater treatment in the forms of DO, BOD, turbidity and NO2- by 8 hours (8-0/opened-closed) and 4 hours (2-2/opened-closed) of aeration time per day of surface aerators was not statistically different [Sig. = .644, .488, .716 and .054 > α (.05)] while the efficiency in the forms of NO3- and P was significantly different at the statistical level of .01 [Sig. = .001 and .000 < α (.01)].
Abstract: Local utilities often face problems of local industrial
wastes, storm water disposal due to existing strict regulations. For
many local industries, the problem of wastewater treatment and
discharge into surface reservoirs can’t be solved through the use of
conventional biological treatment techniques. Current discharge
standards require very strict removal of a number of impurities such
as ammonia, nitrates, phosphate, etc. To reach this level of removal,
expensive reagents and sorbents are used.
The modern concept of rational water resources management
requires the development of new efficient techniques that provide
wastewater treatment and reuse.
As RO membranes simultaneously reject all dissolved impurities
such as BOD, TDS, ammonia, phosphates etc., they become very
attractive for the direct treatment of wastewater without biological
stage. To treat wastewater, specially designed membrane "open
channel" modules are used that do not possess "dead areas" that cause
fouling or require pretreatment. A solution to RO concentrate
disposal problem is presented that consists of reducing of initial
wastewater volume by 100 times. Concentrate is withdrawn from
membrane unit as sludge moisture. The efficient use of membrane
RO techniques is connected with a salt balance in water system.
Thus, to provide high ecological efficiency of developed techniques,
all components of water supply and wastewater discharge systems
should be accounted for.
Abstract: The introduction of more stringent pollution regulations, in relation to financial and social pressures for sustainable development, has pressed toward limiting the volumes of industrial and domestic effluents discharged into the environment - as well as to increase the efforts within research and development of new or more efficient wastewater treatment technologies. Considering both discharge volume and effluent composition, wastewater generated by the textile industry is rated as the most polluting among all industrial sectors. The pollution load is mainly due to spent dye baths, which are composed of unreacted dyes, dispersing agents, surfactants, salts and organics. In the present investigation, the textile dye wastewater was characterized by high color, chemical oxygen demand (COD), total dissolved solids (TDS) and pH. Electrochemical oxidation process for four plate electrodes was carried out at five different current intensities, out of which 0.14A has achieved maximum percentage removal of COD with 75% and 83% of color. The COD removal rate in kg COD/h/m2 decreases with increase in the current intensity. The energy consumption increases with increase in the current intensity. Hence, textile dye wastewater can be effectively pretreated by electrochemical oxidation method where the process limits objectionable color while leaving the COD associated with organics left for natural degradation thus causing a sustainable reduction in pollution load.
Abstract: Sustaining a desired rate of oxygen transfer for microbial activity is a matter of major concern for biological wastewater treatment (MBR). The study reported in the paper was aimed at assessing the effects of microbial products on the specific oxygen uptake rate (SOUR) in a conventional membrane bioreactor (CMBR) and that in a sponge submerged MBR (SSMBR). The production and progressive accumulation of soluble microbial products (SMP) and bound-extracellular polymeric substances (bEPS) were affecting the SOUR of the microorganisms which varied at different stages of operation of the MBR systems depending on the variable concentrations of the SMP/bEPS. The effect of bEPS on the SOUR was stronger in the SSMBR compared to that of the SMP, while relative high concentrations of SMP had adverse effects on the SOUR of the CMBR system. Of the different mathematical correlations analyzed in the study, logarithmic mathematical correlations could be established between SOUR and bEPS in SSMBR, and similar correlations could also be found between SOUR and SMP concentrations in the CMBR.
Abstract: Water supply system consumes large amount of power load during water treatment and transportation of purified water. Many energy conserving high efficiency materials such as DC motor and LED light have recently been introduced to water supply system for energy conservation. This paper performed empirical analysis on BLDC and AC motors and comparatively analyzed the change in power according to DC power supply ratio in order to conserve energy of a next-generation water treatment system called vertical water treatment system. In addition, a DC distribution system linked with photovoltaic generation was simulated to analyze the energy conserving effect of DC load.
Abstract: This paper presents a preliminary attempt to apply classification of time series using meta-clusters in order to improve the quality of regression models. In this case, clustering was performed as a method to obtain subgroups of time series data with normal distribution from the inflow into wastewater treatment plant data, composed of several groups differing by mean value. Two simple algorithms, K-mean and EM, were chosen as a clustering method. The Rand index was used to measure the similarity. After simple meta-clustering, a regression model was performed for each subgroups. The final model was a sum of the subgroups models. The quality of the obtained model was compared with the regression model made using the same explanatory variables, but with no clustering of data. Results were compared using determination coefficient (R2), measure of prediction accuracy- mean absolute percentage error (MAPE) and comparison on a linear chart. Preliminary results allow us to foresee the potential of the presented technique.
Abstract: Trihalogenmethanes (THMs) are disinfection byproducts with non-carcinogenic and genotoxic effects. The contamination of 6 sites close to the water treatment plant has been monitored in second largest city of the Czech Republic. Health risk assessment including both non-carcinogenic and genotoxic risk for long term exposition was realized using the critical concentrations. Concentrations of trihalogenmethanes met national standards in all samples. Risk assessment proved that health risks from trihalogenmethanes are acceptable on each site.
Abstract: SUVA (equivalent to UV254/DOC) value in raw water is a precursor for the formation of trihalomethane during chlorination at a water treatment plant. This study collected rapidly filtered water from an advanced water treatment plant for use in experiments on raw water. The removal rate of treating the trihalomethanes formation potential (THMFP) was conducted by using a biological activated carbon. The hydraulic retention time and SUVA loading were major factors in biological degradation tests. The results showed that biological powder-activated carbon (BPAC) lowered the average concentration of UV254 and value of SUVA in raw water. A removal efficiency of THMFP was present in the treatment of the three primary organic carbon items. These results highlighted the importance of the BPAC had an excellent treatment efficiency on THMFP.
Abstract: A water treatment technology employing the adsorption of dissolved organic contaminants from water and their electrochemical regeneration has been commercialized by Arvia Technology Ltd, UK. This technology focuses the adsorption of pollutants onto the surface of low surface area graphite based adsorbents followed by the anodic oxidation of adsorbed species in an electrochemical cell. However, some of the adsorbed species may lead to the formation of intermediate breakdown products due to incomplete oxidation. The information regarding the formation of breakdown products during electrochemical regeneration of these adsorbents is important for the effective application of this process to water treatment. In the present paper, the formation of the break down products during electrochemical regeneration of various graphite based adsorbents has been demonstrated.
Abstract: Intercalation imparts interesting features to the host graphite material. Two different types of intercalated compounds called (GIC-bisulphate or Nyex 1000 and GIC-nitrate or Nyex 3000) were tested for their adsorption capacity and ability to undergo electrochemical regeneration. It was found that Nyex 3000 showed comparatively slow kinetics along with reduced adsorption capacity to one half for acid violet 17 as adsorbate. Acid violet 17 was selected as model organic pollutant for evaluating comparative performance of said adsorbents. Both adsorbent materials showed 100% regeneration efficiency as achieved by passing a charge of 36 C g-1 at a current density of 12 mA cm-2 and a treatment time of 60 min.
Abstract: Heavy metal transfer in soil profiles is a major
environmental concern because even slow transport through the soil
may eventually lead to deterioration of groundwater quality. The use
of sewage sludge and effluents from wastewater treatment plants for
irrigation of agricultural lands is on the rise particularly in peri-urban
area of developing countries. In this study soil samples under sludge
application and wastewater irrigation were studied and soil samples
were collected in the soil profiles from the surface to 100 cm in
depth. For this purpose, three plots were made in a treatment plant in
south of Tehran-Iran. First plot was irrigated just with effluent from
wastewater treatment plant, second plot with simulated heavy metals
concentration equal 50 years irrigation and in third plot sewage
sludge and effluent was used. Trace metals concentration (Cd, Cu)
were determined for soil samples. The results indicate movement of
metals was observed, but the most concentration of metals was found
in topsoil samples. The most of Cadmium concentration was
measured in the topsoil of plot 3, 4.5mg/kg and Maximum cadmium
movement was observed in 0-20 cm. The most concentration of
copper was 27.76mg/kg, and maximum percolation in 0-20 cm.
Metals (Cd, Cu) were measured in leached water. Preferential flow
and metal complexation with soluble organic apparently allow
leaching of heavy metals.
Abstract: Statistics Canada stated that the wastewater treatment
facilities in most provinces are aging and passes 63% of their useful
life in 2007 the highest ratio among public infrastructure assets.
Currently, there is no standard condition rating system for wastewater
treatment plants that give a specific rating index that describe the
physical integrity of different infrastructure elements in the treatment
plant and its environmental performance. The main objective of this
study is to develop a condition-rating index for wastewater treatment
plants mainly activated sludge systems. The proposed WWTP CRI, is
based on dividing the treatment plant into its three treatment phases;
primary phase, secondary phase and the tertiary phase. The
condition-rating index will reflect the infrastructures state for each
phase, mainly tanks, pipes, blowers and pumps.
Abstract: Freeze concentration freezes or crystallises the water
molecules out as ice crystals and leaves behind a highly concentrated
solution. In conventional suspension freeze concentration where ice
crystals formed as a suspension in the mother liquor, separation of
ice is difficult. The size of the ice crystals is still very limited which
will require usage of scraped surface heat exchangers, which is very
expensive and accounted for approximately 30% of the capital cost.
This research is conducted using a newer method of freeze
concentration, which is progressive freeze concentration. Ice crystals
were formed as a layer on the designed heat exchanger surface. In
this particular research, a helical structured copper crystallisation
chamber was designed and fabricated. The effect of two operating
conditions on the performance of the newly designed crystallisation
chamber was investigated, which are circulation flowrate and coolant
temperature. The performance of the design was evaluated by the
effective partition constant, K, calculated from the volume and
concentration of the solid and liquid phase. The system was also
monitored by a data acquisition tool in order to see the temperature
profile throughout the process. On completing the experimental
work, it was found that higher flowrate resulted in a lower K, which
translated into high efficiency. The efficiency is the highest at 1000
ml/min. It was also found that the process gives the highest
efficiency at a coolant temperature of -6 °C.
Abstract: A shaft-type activated sludge reactor has been
developed in order to study the feasibility of high-rate wastewater
treatment. The reactor having volume of about 14.5 L was operated
with the acclimated mixed activated sludge under batch and
continuous mode using a synthetic wastewater as feed. The batch
study was performed with varying chemical oxygen demand (COD)
concentrations of 1000–3500 mg·L-1 for a batch period up to 9 h. The
kinetic coefficients: Ks, k, Y and kd were obtained as 2040.2 mg·L-1
and 0.105 h-1, 0.878 and 0.0025 h-1 respectively from Monod-s
approach. The continuous study showed a stable and steady state
operation for a hydraulic retention time (HRT) of 8 h and influent
COD of about 1000 mg·L-1. A maximum COD removal efficiency of
about 80% was attained at a COD loading rate and food-tomicroorganism
(F/M) ratio (COD basis) of 3.42 kg·m-3d-1 and 1.0
kg·kg-1d-1 respectively under a HRT of 8 h. The reactor was also
found to handle COD loading rate and F/M ratio of 10.8 kg·m-3d-1
and 2.20 kg·kg-1d-1 respectively showing a COD removal efficiency
of about 46%.
Abstract: The present disposal routes of sewage sludge represent a critical environmental issue in Egypt. Recently, there has been an increasing concern about sewage sludge management due to the environmental risks, which resulted from the fast expansion of wastewater treatment plants without equal attention in dealing with the produced sludge. This paper discusses the current situation of sewage sludge management in Egypt presenting a brief overview of the existing wastewater treatment plants, sludge production and characteristics as well as options of beneficial use and potential demand of sewage sludge under Egyptian conditions. The characteristics of sewage sludge are discussed considering the results of own sampling and analysis as well as previous studies. Furthermore, alternative treatment scenarios for sewage sludge, which have been recently developed in Egypt, are discussed and perspectives for a sustainable agricultural use are outlined.