71 MWA92 WATER MALAYSIA '92 8TH ASPAC - IWSA REGIONAL WATER SUPPLY CONFERENCE & EXHIBITION PUTRA WORLD TRADE CENTRE KUALA LUMPUR, MALAYSIA 26 - 30 OCTOBER 1992 TECHNICAL PAPERS VOLUME 1 CONTAINING PAPERS TO BE PRESENTED ON 27 OCTOBER 1992 Organised by: UndeT lhe auspices of: THE MALAYSIAN INTERNATIONAL WATER -—••• WATER SUPPLY ASSOCIATION ASSOCIATION AIDE ?\ UU10* WATER MALAYSIA '92 8TH ASPAC - IWSA REGIONAL WATER SUPPLY CONFERENCE & EXHIBITION TECHNICAL PAPERS VOLUME 1 CONTAINING PAPERS TO BE PRESENTED ON 27 OCTOBER 1992 FOR SESSIONS 1A IB 1C 2A 2B 2C i SUPPLY ! • ^ ; • .gu» ext 141/142 Organised by: Under the auspices ol: IWSA ^fiRÈ^ THE MALAYSIAN INTERNATIONAL ^ ffrr*™ WATER WATER SUPPLY f iMiaMl' ASSOCIATION ASSOCIATION 1 AIDE CONTENTS TECHNICAL SESSION 1A PRETREATMENT, EVALUATION AND TRENDS IN WATER TREATMENT Pretreatment of Contaminated Raw Water of Public Water Supplies by Fixed-film Biological Processes - RBC and BCA 1A1-1 Chalo-Fuel Ouyang & Cheng-Shang Ying •'•.is Evaluation of Water Purification System Referring to Mutagenicity 1A2-1 Yoshinorl Kurosawa, Yasumoto Magara & Yoshiha.ru Hisamatsu Trends in Water Treatment - Application in Malaysia , 1A3-1 F. W. Crowley TECHNICAL SESSION 2A WATER TREATMENT - FILTRATION Slow Sand Filter for Groundwater Recharge. Ten Times Longer Filter Run Than was Usual Up to Now 2A1-1 Dr. h. c, sc. tech. ETH Maarten Schalehamp Assessing Membrane Filtration for Particulate Removal 2A2-1 Takasl Kohno, Yashikazu Hoh & Yosihide Kaiya Filtration of Horizontal Flow Filter 2A3-1 K. S.L.LO& C. S. Lay TECHNICAL SESSION IB RIVER WATER QUALITY MANAGEMENT Water Quality Computer Simulation Modelling of Sg. Linggl 1B1-1 Mohd. Akbar Johari Classification of Rivers in Malaysia According to Various Beneficial Uses and Water Quality 1B2-1 Dr. Fauzi Abd. Samad & Dr. Abu Bakar Jaqfar The Use of Database Management Systems in Water Quality Management 1B3-1 /. Chanthiran TECHNICAL SESSION 2B ASPECTS OF WATER SUPPLY - GLOBAL CHANGE, STRATEGY AND CRITERIA Impacts of Global Change on Water Supply, and Response Measures 2B1-1 Shinichlro Ohgakl, Tomoyasu Matsuda, Sombo Yamamura & Hiroyasu Yoda The Strategic Aspects of Water Supply .....2B2-1 M. J. Rouse Recent Water Resources Criteria for the Production of Drinking Water 2B3-1 M. Rapinat TECHNICAL SESSION 1C PRIVATISATION Privatisation of the Water Industry 1C1-1 Brian R. Thorpe Privatisation of Water Supplies - Malaysian Experience 1C2-1 Ir. V. Subramaniam Privatisation of Water and Wastewater Services ..... 1C3-1 T. A. Rogers TECHNICAL SESSION 2C PRIVATISATION Privatised Water - Organisation, Regulation and Funding 2C1-1 J, JeJJery Involvement of the Private Company In Water Supply, The New Development Era in Indonesia 2C2-1 Priyono Sallm The Impact of The Private Development of Water Systems in Urban Areas of Mindanao 2C3-1 Ernesto B. San Juan TECHNICAL SESSION 1A PRETREATMENT, EVALUATION AND TRENDS IN WATER TREATMENT Pretreatment of Contaminated Raw Water of Public Water Supplies by Fixed-film Biological Processes - RBC and BCA Evaluation of Water Purification System Referring to Mutagenicity Trends in Water Treatment - Application in Malaysia •I PRETREATMENT OF CONTAMINATED RAW WATER OF PUBLIC WATER SUPPLIES BY MIXED-FILM BIOLOGICAL PROCESSES - RBC AND BCA Chaio-Fuei Ouyang Cheng-Shang Ying Civil Engineering Department China Engineering Consultants, Inc National Central University Chinese Taiwan Chung-Li, Chinese Taiwan Abstract: This study is to carry out experiments and studies on the contaminated raw water of public water supplies prctreatment by Rotating Biological Contactors (RBCs) and Biological Contactor Aeration processes (3uch as Honey Cone-processes) in order to determine its effectiveness in treatment and the feasibility of its used as an alternative to prechlorination. According to the results of this study, it showed that the two biological pretreatment processes exhibited high treatment efficiencies and had significant effectiveness in the removal of ammonia nitrogen (NH3 -N). The capital costs, operating and maintenance costs, land requirement, the stability and reliability of operation, etc were compared and evaluated in the pretreatment of contaminated raw water of public water supplies by the two biological pretreatment processes. key words: Rotating Biological Contactor, Biological Contactor Aeration, contaminated raw water, pretreatment, prechlorination 1. Introduction Even though the raw water of a public water supply are badly polluted nowadays, the treatment of public water has always been processed by adding chemical agent which can not remove odor. In order to remove NH3 -N, Pre-chlorination .is to be used but the massive organic compounds of raw water, which react with chlorine, would produced trihalo-methane,a hazardous carcinogenic substance. The water treatment technique of bio-film process is very effectively to remove BOD, COD, anion surface active agent, particularly UH3 -N removal (Nitrification), A plus is to reduce the pre-chlorine dosage. it is considered a powerful way to suppress the generation of trihalo-methane. This study is to explore the characteristics of bio-film process in the raw water treatment, consisting of the rotating biological contactor process (RBC) and the biological contactor and aeration process (BCA). The sampling 1A1-1 water for this experimentation is picked up directly from Keelung river, the most poorly contaminated water source. This achievement gained from the experimentation is very solid, and its results, after carefully reviewing its applicability, could be substantialized and used as the optimal design parameters on the economic, operational and land requirement basis. 2. Experimental Method and Criteria This study applied two methods, RBC and BCA for experiment of pilot plant in association with the following laboratory equipment: 2.1 Biological contactor Aeration processes (BCA) The experimental installation as shown in Fig. 1, consists of reaction tank, contact filter media, diffuser pipes and etc. Its specification in described as follows: Reaction tank: Dimension:1200m/m LX600m/m WX3500m/m H Contact filter media: Dimension: 600m/mX600m/mX100m/m; Specific surface area 326.16m2 /m3 Porous diameter 13mm,9 unit(3 unit per set),1.08 m per set of honey cone. Diffuser pipe: Type:SD 100 of Tsutsunaka plastic industrial Co., Japan. raw water Material : PVC & Neoprene Dimension: 88 mm0 X 65 mm H c icojnprcsacr pjpunp Diameter air rate:10 1/min per piece Fig.l. Flow Diagram of Number : 6 pieces(2 pieces of per set) BAC PILOT PLANT In the initial experimental stage, three pilot plants were Bet up with the hydraulic loading at 5,12 and 20 m3 /m3 .d, equivalent to 3.75, 9 and 15 1/min in flow rate, respectively. The last stage changed the operational criteria to 12,20,and 30 m3 /m3 .d, equivalent to 9,15 and 22.5 1/min. 2.2 Rotating Biological Contactors Processes (RBC) The specification of 3 four stage RBC pilot plant is shown in Table 1 • the primary installation as shown in Fig. 2. Table 1 The equipment specification of RBC pilot plant Item Specification Disc Type plate type Disc material acrylic board Disc diameter 300 m/m Disc thickness 2 m/m Disc interval 15 m/m Disc number 15 pieces X 4 = 60 pieces 2 Total surface area of Discs 8.48m The ratio of Disc submergence 40% Volume per stage 9.8 1 Volume of settling tank 11.3 1 Liquid Volume/Disc surface area 4.62 l/m* 1A1-2 un.it I cm "^ (1) Plain (2) section Fig.2. Schematic Diagram of RBC Pilot Plant The hydraulic loading of the three pilot plants were 200, 500 and 800 1/m -d,equivalent to 1.178, 2.945 and 4.712 1/min in flowrate, respectively. 2.3 Item and Method of Analysis The study was carried out under continuous conditions and the items of daily analysis included temperature, PH, turbidity, alkalinity, dissolve oxygen, biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium nitrogen(NH3 -N),nitrite nitrogen (NOjf*-N) , nitrate nitrogen(NO3~-N) and chlorine demand, in accordance with the 16-th edition of the Standard Methods. 3. Results and Discussions The study took a whole year, starting in the mid-August, 1986 and continued to the end of August, 1987. The influent water was tamed for half month to get it matured, then for a variety of testing. , The water quality of the raw water during the experiments are pH=6.0— 7.2, turbidity:5.6 ~ 81NTU, DO=0.8 — 8.6 mg/1, BOD=0.3 ~5.6 mg/1, COD= 3.14 — 18.6 mg/1, NH3 -N=2 .4 ~9 . 4mg/l, NO2~ -N=2 .1 — 442 .2ug/l, NO3"-N=0.55 — 2.06mg/l, water temperature=15—3lTC- The water treatment system used on Taiwan normal includes coagulation, floculation, settling, rapid filtration and disinfection, provides that the raw water quality conforms to the standards of the second class for public water supply. This will serve as the basis in the discussion and comparison of the study results with the performance of other water treatment systems. 3.1 Experimental Results of BAC 3.1.1 Treatment Characteristics under Different Hydraulic Loading According to the experimental results,it can be seen that as the hydraulic loading increases, the quality of the treated water expressed in turbidity, BOD, COD and NH3 -N removal deteriorales. This is caused by the shorter detention time as the hydraulic loading increase. If insufficient time is provided for full reaction, there would be lower removal rates, as illustrated in Fig 3.In Fig 3,it can be found that the removal rate of NH3 -N 'decreases from the hrghest of 92.0% to 71% when the hydraulic loading increases from 5m3 /m3 .d to 30m3 /m3 .d. Thus the removal mechanism of this method was basically nitrification. It was noted from the figure that at the low hydraulic loading, the removal rate of the organic material was not so prominent. While the hydraulic loading was at 5 m3 /m3 .d, and the retention 1A1-3 time maintained at 4.8 hours, most reation notable was nitrification.