Katayon Saed

Characteristics of slag produced from incinerated hospital waste

Ash produced from a hospital waste incinerator was treated using a high temperature melting process at 1200 degrees C. The quality of the produced slag was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), leaching tests and sequential chemical extraction of metals. The slag contained large amounts of SiO(2,) CaO, Al(2)O(3), Sn, Ni, Cu, Ba and B. XRD analysis revealed a moderate crystal structure for the melted slag and identified the main crystals as quartz (SiO(2)), kaolinite (Al(2)Si(2)O(5)(OH)(4)), albite (NaAlSi(3)O(8)) and gibbsite (Al(OH)(3)). The observed crystal structure assists in preventing the leaching of heavy metals from the slag. Furthermore, the leaching results found the produced slag to comply with disposal limits set by the US EPA. Results from sequential chemical extraction analysis showed that metals in the slag exhibited the strongest preference to be bound to the residual fraction (stable fraction), which is known to have very low leaching characteristics. Melting was found to stabilize heavy metals in hospital waste successfully and therefore it can be an acceptable method for disposal.

Accumulation of Heavy Metals (Zn, Cu, Pb, Cd) in Flat-Tree Oysters Isognomon Alatus Exposed to Pig Farm Effluent

Field experiments were conducted to measure the accumulation of heavy metals (Zn, Cu, Pb, Cd) in oysters Isognomon alatus transferred from the Sepang Kecil River (clean area) to the Sepang Besar River (polluted area), for a period of 6 months. Oysters were placed in an area near an effluent from pig farm. There were increase in all metals studied in the oysters introduced to the Sepang Besar River. The metals accumulated by transplanted oysters indicated chronic pollution by metals from the pig farm effluent. A significant difference was found between the accumulation rate of Zn and accumulation rates of the Cu, Pb and Cd. Accumulation rates of metals by oysters under field conditions were found to be 42.70, 1.77, 0.95 and 0.84 µg g m 1 month m 1 for Zn, Cu, Pb and Cd, respectively. It was also found that oysters have abilities to regulate their internal concentrations of metals over a range of external metal concentrations.

Heavy metal depuration in flat tree oysters isognomon alatus under field and laboratory conditions

Oysters Isognomon alatus containing high concentrations of Zn, Cu, Pb and Cd were collected from the Sepang Besar River, and transferred to the Sepang Kecil River where the native oysters contain low metal concentrations. Concentrations of heavy metals in oysters were measured monthly over six months. The concentrations of all metals decreased significantly (p<0.05) for Cd 87%, Pb 83%, Cu 78%, and Zn 59%. In addition, metal depuration in oysters was investigated under laboratory conditions. Oysters were exposed to 100 µg g−1 of metals for two weeks followed by one week of depuration. Our studies suggest that metals in oysters tend to be lost in the order, Cd>Pb>Cu>Zn. A comparison between laboratory and field data showed that depuration of metals under the laboratory conditions is significantly faster than in the field.

Pilot scale microfiltration - coagulation for treatment of retention pond water.

Abstract An evaluation of two commonly used coagulants, alum and ferric chloride was conducted to treat retention pond water using microfiltration. To determine the effectiveness of these coagulants in removing turbidity, color, and total suspended solids two different sets of the experiments were performed. Preliminary test was carried out to evaluate the optimum dosages of coagulants. Optimum turbidity removal was achieved with a 4 and 20 mg/L dosage for ferric chloride and alum, respectively. Generally, coupling microfiltration with coagulation using both alum and ferric chloride exhibited excellent effectiveness for turbidity, color, and total suspended solids removal. The efficiency for alum and ferric chloride for turbidity removal were 96 and 98%, respectively, which was greater than 89% removal using microfiltration alone. Furthermore, microfiltration only demonstrated 81 and 83% removal efficiency for color and total suspended solids removal, respectively. However, microfiltration–coagulation using alum and ferric chloride resulted about 83 and 93% color removal, and 92 and 94% total suspended solids removal, respectively.

Biotreatment of Sludge and Reuse

Sewage sludge, a by-product of domestic wastewater treatment plant, also known as “biosolids”, is generated in millions of tons each year. While sewage sludge disposal is a worldwide problem, local conditions dictate the adoption of a variety of treatment and reuse methods. Among them, composting has been practiced extensively in Malaysia. This chapter discusses the theory of the process, fundamental factors affecting the process, and the basis of solid state bioconversion technique. Numerous case studies exhibiting the large scale and continuous operation of sewage sludge composting and their utilization are also presented in this chapter.

EFFECTS OF HIGH TEMPERATURE MELTING ON FRACTIONATION OF HEAVY METALS IN SEWAGE SLUDGE

ABSTRACT Sewage sludge from aerobic treatment plant was found to contain high amounts of heavy metals. Research was carried out to investigate the speciation and leaching behavior of heavy metals when using high temperature melting technology for treatment. This was achieved by conducting a sequential chemical extraction procedure and EP-TOX leaching test. The thermal treatment led to increased shift of metals from organic fraction to residual fraction, indicating that the thermal treatment caused metals in sewage sludge to become stable. Furthermore, results from leaching test revealed that metals were not leached from the final product after thermal treatment and this was verified using US EPA standard limits. Results from this study indicated that melting technology could convert the sludge to product that can be either reused or landfilled without an adverse environmental impact.

Treatment of Septage and Biosolids from Biological Processes

This chapter deals with processes for biosolids dewatering and septage treatment. Septage is the liquid and solid material pumped from a septic tank or cesspool when it is cleaned. A selection of recent methods that show promising applications is presented. These include: Expressor Press, Som-A-System, CentriPress, screw press, Sun Sludge system, wedgewater bed, vacuum assisted bed, reed bed, biosolids freezing bed, biological flotation, and septage treatment and management systems. When septage is to be ultimately treated at a wastewater treatment plant or independent septage treatment facility, a receiving station is required in order to provide preliminary treatment and equalization. The septage treatment and management options discussed include septage addition to biological wastewater treatment plants, septage land application, septage lagoon disposal, septage composting, and odor control.

Animal Glue Production from Skin Wastes

Animal glue is the most important protein adhesive obtained from animal hides, skins, and bones through hydrolysis of the collagen. Animal glue production has long been a lucrative business in various parts of the world. This chapter discusses pretreatment and conditioning techniques including acidic, alkali, and enzymic proteolysis, which are involved during animal glue production. The extraction methods, including denaturation and thermal treatment, are also discussed. The possible improvement of pot life and moisture resistance of animal glue using chemical modification technique is presented. The application of micro-bubble technique for glue production from cow skin is also introduced.

Biosolids Thickening-Dewatering and Septage Treatment

This chapter deals with processes for biosolids dewatering and septage treatment. Septage is the liquid and solid material pumped from a septic tank or cesspool when it is cleaned. A selection of recent methods that show promising applications is presented. These include Expressor Press, Som-A-System, CentriPress, screw press, Sun Sludge System, wedgewater bed, vacuum-assisted bed, reed bed, biosolids-freezing bed, biological flotation, and septage management systems.

ARSENIC REMOVAL FROM AN EX-TIN MINING WATER POOL USING A MICROFILTRATION-COAGULATION PROCESS

The removal of arsenic from water by a microfiltration‐coagulation process was investigated. In general, arsenic removal was enhanced in the presence of a coagulant. Arsenic was removed (83% and 72%) from water containing 243–255μg/l arsenic, resulting in arsenic concentrations of 40μg/L and 68μg/L, using microfiltration‐coagulation and microfiltration, respectively. Furthermore, arsenic removal increased with decreasing specific flux, in which an almost linear relationships (r2 = 0.905) was found to relate the specific flux to arsenic removal during the microfiltration‐coagulation process. Coupling microfiltration with coagulation was also found to be effective in turbidity removal. Turbidity was decreased by 94% using microfiltration‐coagulation processes, while 70% turbidity removal was achieved using microfiltration.