A. Fakhru’l-Razi

Application of membrane-coupled sequencing batch reactor for oilfield produced water recycle and beneficial re-use.

Oil and gas field wastewater or produced water is a significant waste stream in the oil and gas industries. In this study, the performance of a membrane sequencing batch reactor (MSBR) and membrane sequencing batch reactor/reverse osmosis (MSBR/RO) process treating produced wastewater were investigated and compared. The MSBR was operated in different hydraulic residence time (HRT) of 8, 20 and 44 h. Operation results showed that for a HRT of 20 h, the combined process effluent chemical oxygen demand (COD), total organic carbon (TOC) and oil and grease (O&G) removal efficiencies were 90.9%, 92% and 91.5%, respectively. The MSBR effluent concentration levels met the required standard for oil well re-injection. The RO treatment reduced the salt and organic contents to acceptable levels for irrigation and different industrial re-use. Foulant biopsy demonstrated that the fouling on the membrane surface was mainly due to inorganic (salts) and organic (microorganisms and their products, hydrocarbon constituents) matters.

Enhanced settleability and dewaterability of fungal treated domestic wastewater sludge by liquid state bioconversion process

A study was conducted to evaluate the settleability and dewaterability of fungal treated and untreated sludge using liquid state bioconversion process. The fungal mixed culture of Aspergillus niger and Penicillium corylophilum was used for fungal pretreatment of wastewater sludge. The fungal strains immobilized/entrapped on sludge particles with the formation of pellets and enhanced the separation process. The results presented in this study showed that the sludge particles (pellets) size of 2-5mm of diameter were formed with the microbial treatment of sludge after 2 days of fermentation that contained maximum 33.7% of total particles with 3-3.5mm of diameter. The settling rate (measured as total suspended solids (TSS) concentration, 130 mg/l) was faster in treated sludge than untreated sludge (TSS concentration, 440 mg/l) after 1 min of settling time. In 1 min of settling operation, 86.45% of TSS was settled in treated sludge while 4.35% of TSS settled in raw sludge. Lower turbidity was observed in treated sludge as compared to untreated sludge. The results to specific resistance to filtration (SRF) revealed that the fungal inoculum had significant potentiality to reduce SRF by 99.8% and 98.7% for 1% w/w and 4% w/w of TSS sludge, respectively. The optimum fermentation period recorded was 3 days for 1% w/w sludge and 6 days for 4% w/w sludge, respectively, for dewaterability test.

Biosolids accumulation and biodegradation of domestic wastewater treatment plant sludge by developed liquid state bioconversion process using a batch fermenter.

The biosolids accumulation and biodegradation of domestic wastewater treatment plant (DWTP) sludge by filamentous fungi have been investigated in a batch fermenter. The filamentous fungi Aspergillus niger and Penicillium corylophilum isolated from wastewater and DWTP sludge was used to evaluate the treatment performance. The optimized mixed inoculum (A. niger and P. corylophilum) and developed process conditions (co-substrate and its concentration, temperature, initial pH, inoculum size, and aeration and agitation rate) were incorporated to accelerate the DWTP sludge treatment process. The results showed that microbial treatment of higher strength of DWTP sludge (4% w/w of TSS) was highly influenced by the liquid state bioconversion (LSB) process. In developed bioconversion processes, 93.8 g/kg of biosolids was enriched with fungal biomass protein of 30 g/kg. Enrichment of nutrients such as nitrogen (N), phosphorous (P), potassium (K) in biosolids was recorded in 6.2% (w/w), 3.1% (w/w) and 0.15% (w/w) from its initial values of 4.8% (w/w), 2.0% (w/w) and 0.08% (w/w) respectively after 10 days of fungal treatment. The biodegradation results revealed that 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of COD in treated DWTP sludge supernatant were removed after 8 days of microbial treatment. The specific resistance to filtration (SRF) in treated sludge (1.4x10(12) m/kg) was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation compared to untreated sample (85x10(12) m/kg).

Modeling of membrane bioreactor treating hypersaline oily wastewater by artificial neural network.

A membrane sequencing batch reactor (MSBR) treating hypersaline oily wastewater was modeled by artificial neural network (ANN). The MSBR operated at different total dissolved solids (TDSs) (35,000; 50,000; 100,000; 150,000; 200,000; 250,000mg/L), various organic loading rates (OLRs) (0.281, 0.563, 1.124, 2.248, and 3.372kg COD/(m(3)day)) and cyclic time (12, 24, and 48h). A feed-forward neural network trained by batch back propagation algorithm was employed to model the MSBR. A set of 193 operational data from the wastewater treatment with the MSBR was used to train the network. The training, validating and testing procedures for the effluent COD, total organic carbon (TOC) and oil and grease (O&G) concentrations were successful and a good correlation was observed between the measured and predicted values. The results showed that at OLR of 2.44kg COD/(m(3)day), TDS of 78,000mg/L and reaction time (RT) of 40h, the average removal rate of COD was 98%. In these conditions, the average effluent COD concentration was less than 100mg/L and met the discharge limits.

Filamentous fungi in Indah Water Konsortium (IWK) sewage treatment plant for biological treatment of domestic wastewater sludge

ABSTRACT A study was carried out to isolate and identify filamentous fungi for the treatment of domestic wastewater sludge by enhancing biodegradability, settleability and dewaterability of treated sludge using liquid state bioconversion process. A total of 70 strains of filamentous fungi were isolated from three different sources (wastewater, sewage sludge and leachate) of IWKs (Indah Water Konsortium) sewage treatment plant, Malaysia. The isolated strains were purified by conventional techniques and identified by microscopic examination. The strains isolated belonged to the genera of Penicillium, Aspergillus, Trichoderma, Spicaria and Hyaloflorae The distribution of observed isolated fungi were 41% in sewage sludge followed by 39% in wastewater and 20% in leachate. The predominant fungus was Penicillium (39 strains). The second and third most common isolates were Aspergillus (14 strains) and Trichoderma (12 strains). The other isolates were Spicaria (3 strains) and Hyaloflorae (2 strains). Three strains (WWZP1003, LZP3001, LZP3005) of Penicillium (P. corylophilum, P. waksmanii, and P. citrinum respectively), 2 strains (WWZA1006 and SS2017) of Aspergillus (A. terrues and A. flavus respectively) and one strain (SSZT2008) of Trichoderma (T. harzianum) were tentatively identified up to species level and finally verified by CABI Bioscience Identification Services, UK.

Biological treatment of produced water in a sequencing batch reactor by a consortium of isolated halophilic microorganisms

Produced water or oilfield wastewater is the largest volume of a waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m−3 d−1, 1.8 kg COD m−3 d−1 and 3.6 kg COD m−3 d−1) and different total dissolved solids (TDS) concentration (35,000 mg L−1, 100,000 mg L−1, 150,000 mg L−1, 200,000 mg L−1 and 250,000 mg L−1). It was found that with an OLR of 0.9 kg COD m−3 d−1 and 1.8 kg COD m−3 d−1, average oil and grease (O&G) concentrations in the effluent were 7 mg L−1 and 12 mg L−1, respectively. At TDS concentration of 35,000 mg L−1 and at an OLR of 1.8 kg COD m−3d−1, COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L−1, COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83 %, and 85%, respectively.

Study on emergency response preparedness of hazardous materials transportation

Notes the recent increase in interstate shipments of hazardous materials, by road, in Malaysia following rapid expansion in the manufacturing sector. Although there has been no major accident involving transportation of hazardous materials, the high rate of road accidents has raised great concerns concerning motor vehicles carrying hazardous goods and petroleum products. Determines the emergency preparedness and response plans of the transportation companies. Data were obtained from management and drivers, and the results revealed that the companies did not have a proper management system of safe transportation, had inadequate training of personnel, and the transport vehicles were not provided with appropriate tools and equipment for emergency response during mishaps. The drivers lacked general awareness and principal knowledge of hazardous material emergency response. Suggests that there is an urgent need to stipulate legal requirements for hazardous material transportation in Malaysia.

EFFECT OF AGITATION AND AERATION ON BIOCONVERSION OF DOMESTIC WASTEWATER SLUDGE IN A BATCH FERMENTER

ABSTRACT Effects of agitation and aeration rate on microbial treatment of domestic wastewater sludge were investigated in a batch fermenter using mixed culture of Penicillium corylophilum and Aspergillus niger. It was found that liquid state bioconversion (LSB) of wastewater sludge was highly influenced by the effects of agitation and aeration. The maximum production of sludge cake and reduction of organic substances in treated sludge were recorded at 150–200 rpm of agitation speed and 0.5 vvm of aeration rate after 72 h of treatment. No effective results were observed at higher rate of agitation (300 rpm) and aeration (1.5 vvm) as compared to optimum values. The results showed that the minimum level of air saturation (pO2) was adequate to maintain the bioconversion process.

Who Learns When Workers are Trained? A Case of Safety Training of Maintenance Contractors' Workers For A Major Petrochemical Plant Shutdown

This study evaluated the safety training for petrochemical plant maintenance contractors’ workers for a major plant shutdown at a refinery and the correlation between knowledge gained and levels of education. The training was divided into four courses, which were Introduction to Safety, Hydrogen Sulphide, Confined Space and Permit to Work, which were given before starting the job. It is normal practice in any oil, gas and petrochemical plant that contract workers (ranging from 700 to 3000 in Malaysia) are engaged to perform maintenance and modification jobs during any plant shutdown. The first and second levels of Kirkpatricks evaluation training were chosen to evaluate the training exercise. Seven elements were identified for the first level, namely course objectives, course material, trainer, visual aid, feedback, learning and reaction. A survey was developed consisting of 49 questions and the data were analysed using SPSS. For the second level, post-tests were given to the respondents for each course and the scores were tabulated. The correlation between knowledge gained and level of education was significant for hydrogen sulphide only. It is recommended that, for a large group, it would be more effective to group the trainees according to their level of education. For better understanding of a cause-effect relationship in training, mathematical modelling and simulation studies were conducted and a strong correlation between training effectiveness and percentage age grouping was obtained. The curves obtained are typical for the whole exercise, which gave perfect straight lines for Introduction to Safety, Hydrogen Sulphide, Confine Space and Permit to Work, respectively. The curves’ characteristics confirmed the model derived. Subsequently, detailed correlation using the model was performed on all Ei=f(A, X, L, P, Rp, RR, T), which were plots of training effectiveness vs Et as percentages, gave good quantitative parameters for further simulations in the future. Each model describes a common characteristic for all four courses.

Treatment and Biodegradation Kinetics of Microbially Treated Domestic Wastewater Sludge

Abstract A laboratory-scale study was undertaken to evaluate the liquid state bioconversion (LSB) in terms of biodegradation of microbially treated domestic wastewater sludge (biosolids) as well as its kinetics. The potential fungal strains and process factors developed from previous studies were used throughout the study. The results presented in this study showed that an effective biodegradation occurred with the biosolids (sludge cake) accumulated. The maximum biosolids (sludge cake) accumulated (93.8 g/kg of liquid sludge) enriched with the biomass protein (30.2 g/kg of dry biosolids), was achieved which improved the effluent quality by enhancing the removal of chemical oxygen demand (COD), reducing sugar (RS), soluble protein (SP), total dissolved solids (TDS), and total suspended solids (TSS). The higher reduction of specific resistance to filtration (SRF) was observed during bioconversion process. The kinetics results showed that the experimental data were better fitted for the biodegradation efficiency, and biosolids accumulation and biodegradation rate.