Browsing by Author "Ritigala, H.M.T.S."

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    Determination of Raw Water Quality Parameters and Reasons for Failures in Hantana Sewerage Treatment Plant, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2012) Ritigala, H.M.T.S.; Weragoda, S.K.; Kodhithuwakku, S.
    Many health hazards in developing countries and transition-economic countries are related to poor water quality and limited water quantity (Vandeweerd et al., 1997). According to Vandeweerd et al. (1997), more than 90% of sewerage in the developing world is discharged directly into rivers, lakes, and coastal waters without any treatment. Sri Lanka also faces a number of water and wastewater issues and water related health hazards (WHO, 2000). The large cities such as Colombo, Galle, Jaffna and Kandy have serious problems disposal of sewerage, industrial effluents and industrial and of domestic solid waste, as they generate large quantities but have no facilities for their treatment and/or proper disposal (Bandara, 2003). Moreover, Kandy suffers from a serious problem of wastewater disposal which contributes to the pollution of Mahaweli River. There is no proper system of wastewater disposal, and about 80% of used water is released as wastewater (Thrikawala et al., 2008). In addition, highly polluted water is carried by tributaries like Meda-ela, Pussellawa Oya, and Pinga Oya, which connect to Mahaweli River (Dayawansa, 2006). Pussalla Oya catchment was the main source area for the "Hepatitis A" outbreak recorded in Gampola in May 2007 (Abeysinghe, 2007). Due to lack of the knowledge of health hazards by wastewater or scarcity of resources, sewerage treatment and/or improved sanitation were not given due attention by most communities. According to Gijzen (2001) there have been substantial developments in wastewater management and treatment technology. As a solution to the discharge of untreated wastewater, sewerage treatment plants (STPs) have been constructed especially in rapidly urbanizing cities. Main purposes of this research are study the system and find out the reasons for failures and defect identification in Hanthana STP. Determination of the raw water quality parameters, propose the alternatives for occurring issues and waste discharge per day are also considered in this study
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    Determination of the Raw Water Quality Parameters and Examine the Reasons for the Failures in Hanthana Sewerage Treatment Plant
    (Uva Wellassa University of Sri Lanka, 2012) Ritigala, H.M.T.S.
    Sri Lanka faces a number of water and wastewater issues and water related health hazards. These problems arise primarily due to the increasing level of qualitative and quantitative depletion of water resources owing to over- utilization and continuous discharge of wastewater. Sewerage treatment plants (STP) have been constructed in most places to reduce the degradation of water quality and to ensure a healthy environment. The present study has been undertaken to evaluate the raw water quality parameters and find out the reasons for failures and defect identification in Hantana STP.The Hantana sewerage treatment plant is operating on biological treatment method (Suspended growth process and attached growth process) and main treatment units are imhoff tanks and trickling filters. Raw wastewater samples were collected and analyzed for the major water quality parameters, such as biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS) and pH. The obtained results were very much useful in identification and rectification of operational and maintenance problems as well as the future expansion to be carried out in the plant to meet the increased hydraulic and organic loadings. This research will further discuss on the treatment process of Hantana STP along with the findings from the study.
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    Fabrication of Supersand for Water Purification
    (Uva Wellassa University of Sri Lanka, 2018) Thennakoon, R.S.; Weerasooriya, R.; Kumarasinghe, A.R.; Attanayake, A.N.B.; Ritigala, H.M.T.S.
    Fluoride is an essential constituent for both human and animal health that depends on concentration in the medium. The sand is conventionally used in water treatment plants to control water turbidity. This project is aimed at improving its performance using a chemical modification to remove other water contaminants as well. Thus improved substrate is designated as "Super sand". Super sand has proven to be a better adsorbent for the removal of certain heavy metals and dyes from water. Among several treatment technologies applied for fluoride removal, adsorption process has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. Graphene Oxide was synthesized using the modified Hummer’s method. Super sand was synthesized by heating a mixture of sand and graphene oxide/deionized water in an oven for two hours. The process was repeated five times for multiple coating. Graphene oxide and super sand were characterized using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FT-IR) analysis and X-Ray Diffraction (XRD). The applicability of the synthesized material in the water industry for fluoride removal was studied utilizing sand, GO-sand and GO multiple coated sand at varying pH conditions. These results are to be confirmed by conducting further scientific studies.
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    Introducing a Cost Effective Treatment Process to Improve the Effluent Water Quality of Natural Rubber Processing Factories
    (Uva Wellassa University of Sri Lanka, 2016) Gamage, K.H.I.; Premachandra, N.P.; Ritigala, H.M.T.S.
    Most natural rubber processing factories in Sri Lanka tends to discharge their effluent water without treating properly or directly into the nearest stream as proper treatment processes reduce their profit. The objective of this study is introducing a cost effective and commercially viable treatment process to treat the effluent water generated from natural rubber processing factories. The proposed cost effective treatment process includes two treatment steps mainly as Pretreatment Process and Biological Treatment Process. In the Pretreatment Process Total Suspended Solids (TSS) and the Turbidity of the effluent water are reduced using a natural coagulant, and in the Biological Treatment Process the amount of Nitrate and Sulphate dissolved in the effluent water are biodegraded using facultative anaerobic bacteria. As the natural coagulant in the Pretreatment Process Bentonite clay is used and to increase the surface area for the growth of anaerobic bacteria in the Biological Treatment Process a bio brush media made up of bristle fibre coir is used. The effectiveness of proposed treatment process was analysed using effluent water samples collected from eight natural rubber processing factories. In the analysis pH, TSS, Turbidity, Total solids, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Sulphate and Nitrate contents were measured before and after the treatment process. The proposed cost effective treatment process can reduce the TSS content even below the permissible value of 100 mg/1(Turbidity and TSS reduction up to 97% and 54% respectively) and it can reduce the BUD and COD values very close to the permissible levels of 50 mg/l and 400 mg/lrespectively (BOD and COD reduction up to 79% and 70% respectively). Sulphate and Nitrate biodegradation efficiency is nearly three times higher when using the introduced bio-brush media as it increases the surface area for anaerobic microbial growth. As Pretreatment Process needs about 6 hours of contact period and Biological Treatment Process needs about 15 days of contact period, this process is more suitable for medium scale natural rubber processing factories where large amount of effluent water is not produced daily. Keywords: Waste water treatment, Biological treatment, Cost effective treatment
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    Wastewater Treatment Solution for Vehicle Service Stations by Using Ultrafiltration Membrane
    (Uva Wellassa University of Sri Lanka, 2019-02) Wijesinghe, R.R.; Ritigala, H.M.T.S.; Premachandra, N.P.
    A vehicle service station is place where large amount of water is consumed for vehicle washing. This wash water includes contaminants which may cause adverse effects if not treated properly before discharge. Many treatment methods have been suggested by researchers to treat service station effluent. These treatment methods have drawbacks such as large space requirement, high chemical consumption, sludge production, not user friendly compact systems. With that the need for improved techniques to purify contaminated waters arises. Over the past decennia membrane technology has been introduced as a cost effective method to treat water in a smaller foot print. Therefore, a prefabricated membrane reactor using Ultrafilters was introduced to study the effectiveness of removing contaminants from service station wastewater. The treatment process included an oil trap and then the membrane reactor which included a sand filter, carbon filter and a micron filter as the pretreatment steps for the Ultrafilter. As analyzing part, the characteristics of wastewater for parameters such as pH, total suspended solids, oil and grease, biochemical oxygen demand, and chemical oxygen demand were measured in the raw water, oil trapped water and water sent through the membrane reactor. In the absence of any specific discharge standard, the outlet water quality was compared with the Sri Lankan standard for discharge of effluents to inland surface waters. The treatment process was able to keep the parameters within the tolerance limit values of the standards by removing 91.46% of total suspended solids, 98.8% of oil and grease, 78.71% of biochemical oxygen demand and 93.32% of chemical oxygen demand. As a result, this water can be safely discharged into the environment or can be taken into reuse purposes.