Muhammad H. Al-Malack

Coagulation-crossflow microfiltration of domestic wastewater

Abstract The effect of using alum, polyaluminum silicate sulfate (PASS), and lime as coagulants on the performance of crossflow microfiltration of domestic wastewater was investigated. The primary membrane used throughout the study was made of woven polyester, while the dynamic membrane was formed by circulating MnO 2 precipitate. Slug doses of the coagulants were added to the circulation tank of the experimental setup at the beginning of each run. Doses of 20 to 120 mg/l of alum were investigated at pH of 7. The results showed an improvement in flux values with the increase in alum dose until an optimum dose beyond which no significant improvement was seen. Flux improvement was attributed to the agglomeration of particles which can be easily swept away by the shearing actions created by the crossflow velocity. Permeate quality was not found to be significantly affected by the increase in alum dose. PASS, which is an aluminum salt, was seen to behave in the same manner as alum when used as a coagulant. Lime was not found to be a suitable coagulant under these conditions.

Coagulation of polymeric wastewater discharged by a chemical factory

Treatment of an emulsified polymeric wastewater was investigated using sedimentation and coagulation. Settleability studies and jar tests were conducted in order to investigate the effect of sedimentation and coagulation on treatment of the wastewater, respectively. The effect of alum, ferric chloride and ferrous sulphate as coagulants on the treatment of samples collected from two different discharged streams was studied. The results of the settleability studies showed that the wastewater of both streams were insettleable. The jar tests revealed that the wastewater of the first stream was best treated when 200 mg/l of ferric chloride were dosed at pH 9. At optimum conditions, the turbidity and COD of the wastewater were reduced by 99.6 and 99.3 per cent, respectively. Alum was found to produce the best results with wastewater of the second stream, when 250 mg/l were used at pH 9. At optimum conditions, turbidity and COD were reduced by 96.3 and 95.9%, respectively. The COD of the treated wastewater is well below the limit set by the regulatory authority, hence, the wastewater can be discharged to the biological treatment plant of the industrial city.

Use of crossflow microfiltration in wastewater treatment

Abstract Implementation of crossflow microfiltration in the field of wastewater treatment was investigated. The membrane used throughout the research was made of multifilament polyester yarn woven in the form of a double interleave cloth with a pore size of 20–40 μm. Secondary effluent and primary settled sewage, from Blyth Sewage Treatment Plant, were used in the investigation. The study showed that the permeation rate (flux) was linearly affected by the crossflow velocity (CFV) in the case of treating secondary effluent. Permeate quality was also found to be affected by the crossflow velocity values. In addition, the effect of feed suspended solids concentration was found to proceed according to the concentration-polarization phenomena. Using the crossflow microfiltration process in treating primary settled sewage, without pretreatment, was found to be impractical due to the low flux values.

Formation of dynamic membranes with crossflow microfiltration

A dynamic membrane is one of the anti-fouling techniques in the literature, but it has not been thoroughly studied. The formation of a MnO2 dynamic membrane on top of a polyester primary membrane was investigated. The MnO2 used in the investigation was precipitated from potassium permanganate (KMnO4) solution using sodium formate (HCOONa). The study showed that formation of dynamic membranes with particle sizes less than the pore size of the primary membrane was found to proceed according to the standard law of filtration, in the first stages of membrane formation. Later, as particles start to bridge the pores and precipitate on the membrane surface, dynamic membrane formation was found to obey the cake filtration model. General equations to describe each case of dynamic membrane formation were obtained. When wastewater was treated using the dynamic membrane, particles were found to precipitate in the same pattern as in the case of dynamic membrane formation.

Migration of lead from unplasticized polyvinyl chloride pipes

The effect of water quality parameters, such as water pH, temperature, and total dissolved solids (TDS), and direct exposure to UV-radiation on the migration of lead, tin and other metal stabilizers, such as calcium, cadmium, and barium from unplasticized polyvinyl chloride (uPVC) pipes were investigated using locally manufactured pipes. Specimens of 1m were used to investigate the effect of water quality parameters using the circulatory method. To investigate the effect of UV-radiation, specimens of 33cm long were used throughout the research. The investigation was carried out, using the static method at different times of exposure to the UV-radiation. The concentrations of lead, tin, and other metal stabilizers in the water were evaluated using the inductively coupled argon plasma (ICAP) technique. The results on the effect of water quality parameters showed that water pH, temperature, TDS, and time of water circulation were all having an effect on the migration of lead, tin, and other metal stabilizers. On the other hand, exposure to UV-radiation was seen to promote the migration of lead, tin, and other metal stabilizers. A lead concentration of about 0.8mg/l (ppm) was detected after 14 days of exposure to the UV-radiation.

Crossflow microfiltration with dynamic membranes

The effect of dynamic membrane formation on the performance of crossflow microfiltration in treating domestic wastewater was investigated. The dynamic membrane was formed on top of a woven polyester primary membrane by circulating a precipitate of MnO2. The dynamic membrane formation was investigated at different conditions of pH values and KMnO4 concentrations. Secondary effluent from a domestic wastewater treatment plant was used thoughout the study. The MnO2 dynamic membrane was found to improve the performance of crossflow microfiltration by producing higher flux values, extending the running time, and increasing rejection of solids. The optimum permeate flux values were obtained when the dynamic membrane was formed at a pH of 10 and using 100 mg/l of KMnO4. At optimum conditions, the permeate turbidity was found to stabilize at values of less than 0.2 NTU. Cleaning the membrane was achieved easily and efficiently by brushing the outside surface of the primary membrane.

Effect of solar radiation on the migration of vinyl chloride monomer from unplasticized PVC pipes

The effect of direct exposure to solar radiation on the migration of vinyl chloride monomer (VCM) from unplasticized polyvinyl chloride (uPVC) pipes was investigated using locally manufactured and imported pipes. Specimens 33 cm long were used throughout the research. The investigation was carried out, at different times of exposure, by exposing one part of the specimens to the direct sunlight, while keeping the other part in the shade. The VCM concentration in the water was evaluated using the gas chromatography (GC)/head-space technique. A VCM concentration of 2.5 microg/l was detected after 30 days of exposure in direct sunlight. The original initial VCM concentration in the uPVC was predicted, and the diffusion rate of VCM from uPVC pipes was expressed as a function of time.

Treatment of anoxic pond effluent using crossflow microfiltration

Abstract The treatment of anoxic waste stabilization pond effluent was investigated using crossflow microfiltration in conjunction with dynamic membranes. The primary membrane used throughout the study was made of woven polyester, while the dynamic membrane was formed of manganese dioxide (MnO 2 ). Effluent from a lab-scale anoxic waste stabilization pond was treated with and without the addition of slug doses of polyaluminum silicate sulphate (PASS) as a coagulant. Removal of suspended solids, turbidity, COD and E. coli was found to be affected by feed turbidity and the addition of PASS. On the other hand, removal of Streptococcus faecalis and algal species was found to be 100% and was not affected by feed turbidity. This was attributed to their size which could be more than the pore size of the dynamic membrane. Addition of slug doses of PASS were found to have a positive effect on the permeate flux and quality, which was attributed to the influence of crossflow velocity on the agglomerated particles.

Effect of Water Quality Parameters on the Migration of Vinyl Chloride Monomer from Unplasticized PVC Pipes

The migration of vinyl chloride monomer (VCM) from unplasticizedpolyvinyl chloride (uPVC) pipes was investigated using locallymanufactured pipes. Specimens of 33 cm long were used throughoutthe research. The investigation was carried out under differentconditions of water temperature, pH and total dissolved solidsconcentration and at different durations of exposure. The VCMconcentration in the water was evaluated using the gaschromotography (GC)/head-space technique. A VCM concentration ofmore than 2.5 ppb was detected after 30 days of exposure at45 °C. The initial VCM concentration in the uPVC pipewas predicted using equations derived from Ficks first law ofdiffusion. Water tenperature did not affect the migration ofVCM, unless it was raised to high values (i.e. 45 °C).Total dissolved solids (TDS) and pH of water were found toaffect the release of VCM from uPVC pipes. Diffusion rate of VCMwas predicted as a function of pH or TDS values.

Electrochemical oxidation of low phenol concentration on boron doped diamond anodes: optimization via response surface methodology

AbstractDirect electrochemical oxidation of aqueous organic pollutants using Boron doped diamond (BDD) electrode is usually inhibited at low concentration of the target organic pollutant. In this study, a multivariate statistical approach was used to optimize the direct electrochemical oxidation of low phenol concentration using on BDD anodes by employing response surface methodology (RSM) technique. A 24 factorial faced centered central composite design was employed for the experimental design from which the influences of operating parameters were assessed using analysis of variance. The efficiencies of removal of phenol, total organic carbon and chemical oxygen demand, the percentage of aromatic byproducts produced, current efficiency, and energy consumed were collectively taking into account in the RSM optimization. All the six responses fitted quadratic models (R2 of 83.21–98.48%) with the relative contributions of the investigated parameters on the responses following the order: reaction time > pH > ...