Dose Response and Exposure Assessment of Household Hazardous Waste

This study was conducted to assess the risk of health hazards to employees working in local authorities in Malaysia especially workforce involved in waste management. Therefore, the four steps process of Health Risk Assessment has been identified, which include hazard identification, exposure assessment, dose response assessment and risk characterization. It was estimated approximately 22,388 tons of wastes generated every year in Malaysia and around 2.2 % out of that amount were consisting of hazardous household waste (HHW) with mean average generation for each person per day was around 0.02 kg. The waste generation is expected to increase 2 to 3 % per year and estimated to reach approximately 31 million of tones per day in the year 2020. In this study, the household hazardous wastes (HHW) were analyzed for their permissible dose level and the existing hazard level, hazard index and cancer index. Cancer Index for dermal exposure is found to be 5.8 × 10–7 mg/m3, for Inhalation dust 1.4× ×10–1 mg/m3, which falls under Low Risk and for Inhalation aerosol is 5 × ×10–2 mg/m3, under Medium Risk. Extra care must be taken for the management of HHW as if it is improperly managed, it will fall into High Risk

Agriculture drainage affects river water quality

The acidic level of the freshwater is a major concern to water treatment plant operators. Extremely acidic freshwater could affect the operation of the treatment plant in many ways. The cost to neutralisation the water would increase and treatment scheduling would be more complicated. This paper reports the influence of agricultural drainage on river water quality in Bekok river system in Johor, Malaysia. The river is the sole source of freshwater supply to two water treatment plants located at the downstream reach of the river. Three water quality parameters, i.e. pH, Iron and Ammonia-N, were used as an indication parameter. Water samples collected from 16 different river reaches along the 20-km river were analysed. A significant decrease in pH was found near the water intake point, where most of the drained areas are located. The study also found that in general, the quality of the river water was better during low flow condition (non-rainy days) compared to high flow (rainy days). Multiple regression analysis showed that pH was significantly related to Iron and Ammonia contents

Effect of particle size and amount of nonmetallic PCB materials on the mechanical properties of rHDPE/PCB composites

Composites based on recycled high density polyethylene (rHDPE) and nonmetallic printed circuit board (PCB) waste were made through melt compounding and compression molding. In this study, the chemical compositions of the nonmetallic PCB material were determined via XRF and it was confirmed that it contains predominantly 72.7% of glass fiber materials which improve the mechanical performances of the rHDPE matrix. The main aim of this study is to determine the effect of different particle sizes and loadings of nonmetallic PCB on mechanical properties of rHDPE/PCB composite. The results indicated that mechanical properties of composites were excellent when nonmetallic materials with particle size from 0.09 to 0.15 mm and adding amount was 30 wt%. Microscopic images revealed that nonmetallic particles with the size of 0.07-0.09 mm and 0.09 -0.15 mm contained majority of single glass fibers whereas, bigger particle sizes of 0.15-0.3 mm and 0.3-0.5 mm, contained glass fibers in the form of bundles and large resin sheet

Effect of Organic Loading Rate on Hydrogen (H2) and Methane (CH4) Production in Two-stage Fermentation under Thermophilic Conditions using Palm Oil Mill Effluent (POME)

The present study dealt with hydrogen and methane production in a sequential up-flow anaerobic sludge blanket (UASB) and continuous stirred tank reactor (CSTR) at thermophilic temperature. The POME was used as a suitable substrate of carbon source. The effect of various OLR was investigated from 25 kg-COD/m3·d to 125 kg-COD/m3·d at a constant hydraulic retention time (HRT) of 6 h. The UASB-H2 reactor was operated successfully at the OLR of 75 kg-COD/m3·d when the proportion of H2 in biogas, volumetric production rate of H2, specific hydrogen production rate (SHPR) and H2 yield reached the maximum values of 35%, 2.1 l/d, 175.15 ml H2/g MLVSS-d and 49.22 ml H2/g CODapplied respectively. Further, the effluent from the UASB was directly fed into the CSTR at various OLR ranging from 4 kg-COD/m3·d to 20 kg-COD/m3·d for CH4 production. The maximum CH4 content, volumetric production rate of CH4, specific methane production rate (SMPR) and CH4 yield obtained were 65%, 13 l/d, 325.13 ml CH4/g MLVSS-d, and 155.87 ml CH4/g CODapplied respectively. The effluent from CH4 reactor was recycled at feed flow rate recycle ratio of 1:1 to UASB unit and pH was maintained at 5.5, subsequently resulted in COD removal of 85%

Electromagnetic technology on sewage treatment

Magnetic treatments for water and wastewater attract a special attention due to their safety, ecological purity, simplicity and low operating costs. Thus this study was carried out in order to determine the feasibility and effectiveness of applying magnetic technology for a better understanding of the sewage characteristics. The main objectives of this research are to investigate the feasibility of magnetic technology in assisting sedimentation of suspended particles and to understand the mechanism and impact of magnetic application in sewage. The effects of various parameters, magnetic field strength, flow rate, usage of pin-jet and magnetic orientations are used to investigate their effectiveness on the suspended solids removal. A series of electromagnets magnets was used as a reactor in this study and the sewage was taken from Taman Sri Pulai, Johor with estimated PE of 10,300. Experiments indicate that suspended solids removal increases as magnetic field strength and exposure time are increased and flow rate is decreased. It was found out that magnetic field increases the suspended solids removal by 41 percent to 49 percent at 670 Gauss compared to untreated raw sewage. Besides that usage of pin-jet in the magnetically treatment reactors also help to increase another 6 percent of the suspended solids removal. Study carried out also shows that magnetic field enhances the suspended solids removal by accelerating the settling of sludge (settlement time) as well as increasing the sludge density. Hence this technology is definitely beneficial in reducing the volume of sedimentation tank as well as increasing the treatment plant efficienc

A review on printed circuit board recycling technology

From the use of renewable resources and environmental protection viewpoints, recycling of waste printed circuit boards (PCBs) receives wide concerns as the amounts of scrap PCBs increases dramatically. However, treatment for waste PCBs is a challenge due to the fact that PCBs are diverse and complex in terms of materials and components makeup as well as the original equipment's manufacturing processes. Therefore, it is urgent to develop a proper recycle technology for waste PCBs. Several recycle technologies were review in this paper. From the review, it can be said that, PCBs recycling process usually includes three process which is pretreatment, physical recycling, and chemical recycling. PCBs recycling generally start from the pretreatment stage, which include disassembly of the reusable and toxic parts. After pretreatment process, PCBs are treated using physical recycling process. Physical recycling involves a preliminary step were size reduction of the waste is performed followed by a step in which metallic and non-metallic fractions are separated and collected for further management. In the end, materials are finally recovered after chemical recycling process. In this review, chemical recycling consists of pyrolysis process and gasification process. While, metal fraction can be treated by pyrometallurgical, hydrometallurgical, or biotechnological process

An empirical model for sedimentation of suspended solids under influence of magnetic field

The magnetic treatment of wastewater is an alternative simple approach by which the wastewater that need to be treated flow through a magnetic field, and consequently some of its physicochemical properties such as suspended particles changes. The primary propose of wastewater treatment is to remove the suspended and soluble organic constituents measured as chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the incoming liquid streams. The essence of flocculation process is the aggregation of suspended coagulated particles to form larger flocs amenable to separation from the suspending medium by some subsequent physical process, generally sedimentation. Using performance data from the application of magnetic field of 0.55 Tesla in circulation flowing system, empirical mathematical models were developed in this paper relating suspended solids (SS) removal efficiency to operating flow rate and retention time. The obtained experimental results showed that percent of SS removal increased with increasing magnetic exposure time at lower flow rates. The model coefficients were derived from the combined analysis of well correlated sets of data, thus giving a good indication for their possible general applicability. The analysis of experimental data also gave a relationship between SS and chemical oxygen demand (COD) removal efficiencies

Removal of COD and turbidity to improve wastewater quality using electrocoagulant technique

Electrocoagulation (EC) is becoming a popular process to be used for wastewater treatment. The removal of COD and turbidity from wastewater by EC using iron (Fe) electrode material was investigated in this paper. Several working parameters, such as pH, current density, and operating time were studied in an attempt to achieve a higher removal capacity. Wastewater sample was made from milk powder with initial COD of 1140 mgL-1 and turbidity of 491 NTU. Current density was varied from 3.51 to 5.62 mA cm-2, and operating time of between 30 and 50 minutes. The results show that the effluent wastewater was very clear and its quality exceeded the direct discharge standard. The removal efficiencies of COD and turbidity were high, being more than 65 % and 95 %. In addition, the experimental results also show that the electrocoagu lation can neutralize pH of wastewater

Effects of nutrients in sewage sludge on holticulture plants

SEPKA-ISEED 2016 is the first international joint conferences events between Faculty of Civil Engineering, Universiti Teknologi Malaysia and National Institute of Technology (NIT), Kagoshima College, Japan. These joint conferences focus on various branches in civil engineering and technology. Seminars and symposium are function as a platform to recommend any appropriate remedial action for the implementation and enforcement of policies related to civil engineering fields. Furthermore, it will provide opportunities to market faculty expertise in any Civil Engineering fields (i.e: structural engineering, environmental engineering, geotechnical engineering, and hydraulic and hydrology engineering)

Enhancing suspended solids remove from waswtewater using Fe electrodes

This paper investigates the effect of electrocoagulation (EC) process on the removal of suspended solids (SS) from wastewater. In a batch electrochemical cell experimental set up, two monopolar iron (Fe) plate were used as electrodes (anodes and cathodes). Synthetic wastewater, made of milk powder with concentration of 700 mg/L, was treated using 1M HCl for pH adjustment before it was used as electrolyte. Preliminary results show that the EC process is able to enhance the removal of suspended solid, turbidity and carbon oxygen demand in wastewater. The removal rates of those elements were increase with treatment time