Stp Report.docx 4i432

Report on Site Visit at Batu Ferringhi Sewage Treatment Plant

Prepared by 8 NOVEMBER 2017

INTRODUCTION School of Civil Engineering USM has conducted a site visit to Batu Ferringhi sewage treatment plant in Pulau Pinang. The site visit has been held on 1 November 2017 for some review on an actual sewage treatment plant site. Prof Hamidi is the person in charge to handle this site visit. From the site visit that we have experienced, we able to know more detail about the treatment process occur at the Batu Ferringhi Sewage Treatment Plant (STP). It takes about 2 hours to arrive at Batu Ferringhi Sewage Treatment Plant. After arrive to the site, meeting with the people in charge of guiding us, a short brief and video presentation about the project was given by staffs there to start the tour around the site. All the safety precaution was given by site supervisor before student were guide to waste water treatment process and while walking through, the supervisor has explained to us some types of equipment used. We were exposed to various machineries and also had the chance to observe the types of equipment including rotary drum fine screen, air compressor system, oxidation biological reactor, gas holder and many more. We finished our tour at about 4.00 pm before came back to campus. Safety is after all the most important aspect in a construction project. This outdoor experience provided us with a more in-depth and hands on experience on civil engineering water treatment. We were able to question, understand and absorb the logic behind the machineries,techniques, and methodology theory learnt in class.

OBJECTIVE     

To familiarise ourselves with the operations at the water treatment plant site. To and supplement information presented in the self-study report. To give us an opportunity to explore and recognize different sorts of treatment facilities and technologies used. To make us understand the significance of teamwork while working together with the team on site To understand and be aware of the importance of safety on site where we need to take care by following the safety precautions

BACKGROUND Batu Ferringhi STP is located on a 1.3 ha site at the north of Penang Island.It utilizes sequencing Batch Reactor Technology designed to serve an ultimate population of 60,000 Population Equivalent. The Batu Ferringhi STP is designd to comply with Standarb B of Environmental Quality (Sewage) Regulations 2009.This is based on incoming raw sewage strength of 300mg/l of SS and 250 mg/l of BOD5.The plant is also designed to achive nitrogen removal thorugh nitrification and denitrification process along with BOD5 removal in reactor tanks.The treated effluent will be discharged via marine outfall structure constructed approximately 500mm to seabed. The construction of the Batu Ferringhi Sewage Treatment Plant started on 14 May 2014 abd was completed on 13 Jan 2017.

PROJECT DESCRIPTION Batu Ferringhi STP utilisez Sequencing Batch Reactor (SBR)Process,which has capability to remove BOD,COD,Suspended Solids(SS) and Nitrogen

Items

Population Equivalent(PE)

Design Connected(July 2017)

60,000 36,500

Sewage Flow Daily Average(m3/d) 13,500 8,200

Batu Ferringhi sewerage catchment is located the coastal area north of Penang Island and Covers an area of approximately 327 ha.The catchment runs from Royal Malay Army Camp from one end of the catchment to Petronas Rest House at the other end,and is boundd on the north by the Andarman Sea and all its remaining boundary by Hutan Simpan Bukit Kerajaan dan Hutan Simpan Teluk Bahang with Sungai Batu Ferringhi and Sungai Mas crossing the catchment from south to the north of the catchment. Sewage treatment(domestic wastewater treatment) is the process of removing contaminants from waste water and household sewage.Its objective is to produce an environmentally safe treated effluent suitable for disposal or reuse.The schematic of the liquid and solids treatment process is shown below.

Overall Sewage Treatment Process Sewage Influent

Main Inlet

Preliminary Treatment

Equilization Tank

SBR Tanks Sludge Dewatering(20% dry solid)

Biosolid disposed offsite

Sludge Thickening(4% dry solid)

Liquid Treatment Process

Wastewater treatment system is categorized to primary, secondary and tertiary treatment. Primary treatment is physical stage and it function is to protect the equipment and pipes of the station. Secondary treatment is biological process and it function is carrying out all operations and biotic oxidation of organic material and disposal of toxins. Tertiary treatment is Chemical process and it function is filtering clear water that comes from the clarifiers and then disinfected by UV ligh or chlorine.

 Primary treatment Primary treatment process includes main pump station, screen, grit chamber removal and Settling Tank "Primary sedimentation tank ". Firstly, the water will be pumped from the sewage lift stations, mean pump station and tanker filling to the basic station. Then the influent sewage water collects in inlet chamber. After that it goes to screen that remove all large objects and floating materials that greater than 3 mm, like cans, rags, sticks and plastic packets which may damage the equipment because of clogging of pipes and accumulate in settling basins. Then , it goes to grit chamber removal to remove inert and inorganic material like sand, gravel, road grit, metal and glass pieces to protect equipment from abrasion and prevent pipe clogging, accumulation in settling basin and digesters. The length of the channel of grit removal is between 10 – 20 cm and the depth of it 30 – 40 cm. There is counter the speed of water flow that count the flow of water and controlled. The speed of flowing water is between 30 – 35 m/s Finally, the sewage water goes to settling tank that used to remove the suspended organic solids by gravity settling and thus reduce the load on subsequent biological treatment units. So the solid will settle at the bottom of the tank and it will form as sludge, then it removes by mechanical scrapers. Also at the top of tank, the grease and oils rise to the surface and they are removed by a skimming system. As shown in figure1, the process of primary treatment.

Figure 1  Secondary treatment Secondary treatment is known as biological treatment. It includes two distribution boxes, two oxidation ditches, two clarifiers, recycle activated sludge pumps and filter feed pumps.

The wastewater goes and collects in the distribution box 1 which is used for mixing water and distribute evenly to oxidation ditches. The length of Oxidation ditch are between 30 – 40 m and it is between 4.5 – 5 m depth. Then the wastewater goes to Oxidation ditches which consists of large tanks is divided into four parts (anaerobic, aerobic, anaerobic and aerobic basins) and provide fans to move the water and mix it with dissolve oxygen and bacteria to grow and removed by settling tank . The anaerobic basins content anaerobic bacteria which is in the nitrification process that elimination of nitrite and convert it to ammonia as indicates in the following equation[ No3 basins

which

N3 ] . It must take care on the amount of dissolved oxygen in the has

been

0.5

mg

per

liter.

While aerobic basin content aerobic bacteria and should provide suitable environment for growing bacteria in aerobic basins by provide dissolve Oxygen and fans for mixing.

The amount of bacteria in the basin is around 600 m3. Then the bacteria get rid of ammonia and converted to nitrate as indicates in the following equation [ NH3

No2,No3 ] by nitrification process . It must take care on the amount of

dissolved oxygen in the basin which has been 1- 4 milligrams per liter. After one day of Oxidation process, the wastewater will collect again in distribution box2 to mix it and distribute evenly to two clarifiers to separate the clear water from the sludge by settling the sludge and the sludge appear in three colors, white, brown and black. White sludge means the size of bacteria very small, brown sludge means the process going well and black sludge means the amount of sludge high in water and should remove .The sludge daily test is done to determine the amount of deposition of the active sludge in the oxidation basin by using Cylinder of measuring sludge. It must the amount of sludge be between 300-450 milligrams per liter. If the quantity of sludge increased, then it must discharge to the sludge drying beds. The sludge will goes to recycle activated sludge pumps to treat the sludge and use it for agriculture purpose as form of fertilizer and the clear water goes to filter feed pumps and then to sand filters. As shown in Figure 2

Figure 2

 Tertiary treatment Tertiary treatment is Chemical treatment of the basic filtering is relatively clear water that comes from the clarifiers and then disinfected by UV light or chlorine. It consists of sand filters, chlorine dosing and treated water tank. The water goes to sand filters by filter feed pumps that used to get rid of suspended solids in the effluent of the clarifiers. The sand filter is consist of one layer of carbon to protect the filter from corrosion then three layers of sand in different sizes small , medium and large. The capacity of water in one filter is between 130 m 3 – 160 m3 and the water remain one day in filter. Then the water disinfects by chlorine systems that use chlorine gas which remains 6 hours in water to kill bacteria and germs which remaining in the effluent of sand filters. Finally the treated water will saved in treated effluent tank. As shown in figure 3

Figure 3

CONCLUSION In conclusion, from this site visit, we are able to know the flow or sequences of wastewater treatment plant at Batu Ferringhi Sewage Treatment Plant.. Before we go back to USM, we are able to see the control system of the plant and the laboratory. Although we are not able to visit every part of the sewage treatment plant process due to the lack of time, but this visit has gave us many information regarding to the subject EAP315 Wastewater Engineering.