2017丁酉农历新年

 

Internship in Nestlé - 26th Jan 2017 (8am - 5pm)

At 11.00 a.m., Chow delivered a spare feed diaphragm pump and filter clothes for the filter press system. He advised us always to clean the surface of filter clothes using a water jet after using it.

Between 9.00 a.m. and 4 p.m., I observed the unit operations and meanwhile, I followed up on the commissioning projects in the WWTP site, mainly the new DAF operation.

Today we would monitor the colour (quality) of the effluent from DAF. We monitored the pH value of the fluid in the flocculator. The purpose of pH correction system is to provide a desired pH range for the physical-chemical process inside the flocculator. However, the reading displayed by the pH meter was unsteady and fluctuated within a wide range, e.g. from pH 4.0 to pH 7.0, which made it difficult to adjust the NaOH dosing system accurately.

Then Istiak guided us through the procedure of doing pH probe recalibration of the flocculator while performing the demonstration. He suggested us to conduct the recalibration every month or when the pH reading fluctuates within a wide range. Firstly the probe was rinsed with clean water. Two pH buffer solutions were used, with pH values of 4.01 and 7.01 during recalibration. Eventually, the pH reading varied with a narrow range, and the effluent was relatively clear.

Later he showed us the steps of operating the touch panel of the DAF unit so that we can control the DAF system by adjusting the settings accordingly. He explained to us the main differences between new and old DAF units are:

(a)   Air saturation system, and

(b) Sediment discharge system. An auger is installed for new DAF to compact, dewater and transfer the sediment towards the sediment valve, which is opened periodically releasing the sediment. Currently, the setting is once every hour.

Internship in Nestlé - 25th Jan 2017 (8am - 5pm)

At 9.15 a.m., we had a daily review meeting with the operators.

At 9.30 a.m., Fam asked me to help him generate several adhesive stickers of black words with yellow background to label the chemical dosing systems in the WWTP. It was my first time using the label dispenser in a technical store.

At 12.00 p.m., Fam shared some ideas with me about the working principles and theories behind the DAF process. He told me that only certain suitable size of air bubbles is generated and attached to the solids to allow the solid floatation before being scrapped off at the water surface. Besides that, there are several DAF process arrangements and operating conditions.

At 2.30 p.m., Jaclyn, Satiya, Vasu and I were in the DPRS control room to summarize the steps of operating the touch panel to display the parameters to be recorded. We had prepared a written procedure and checklist so the operators could follow up easily.

Between 10.00 a.m. and 5.15 p.m., Jaclyn, the operators and I were in WWTP to follow up on the new DAF commissioning. Istiak, a process engineer, was in charge of the new DAF commissioning project. The old, small DAF unit was switched off while the influent was fed into the new, larger DAF unit. The mechanical parts such as the scrapper system of DAF were in normal operation.

Istiak performed a simple jar test experiment to monitor the chemical dosing systems of the flocculator at the site. The chemicals used for DAF are FeCl₃, NaOH and polymer solution. The desired outcome is a distinct separation between floc sediments and a relatively clear solution. The chemical dosing systems are ready for operation except for NaOH.

At the same time, three intermediate bulk containers (IBC) of NaOH arrived for DAF commissioning. The NaOH dosing pump was tripped several times after turning on. Istiak suspected that there was an airlock in the pipeline connecting the IBC and NaOH dosing point on the flocculator. However, the contractors were taking half-day leave and we had tried several alternative methods so that NaOH could be effectively dosed to the DAF system. It took a certain time to fix this problem.

Later we adjusted and monitored the chemical dosing systems for several times by trial and error. Eventually, we obtained a satisfactory outcome before sending it into the DAF separator unit.

Internship in Nestlé - 24th Jan 2017 (8am - 5pm)

At 8.30 a.m., Tee had asked me to help him draw a flow diagram of liquid sugar transfer from the tanker and it needed to be done by today.

At 9.15 a.m., we had a meeting with the operators as usual.

Between 10.00 a.m. and 12.05 p.m., the DPRS training session was conducted by introducing Maintenance Cleaning of MBRs which is performed weekly. The chemicals used during the maintenance cleaning of fiber membranes are sodium hypochlorite (NaOCl) and citric acid. Both chemicals cannot be dosed at the same time to prevent the formation of toxic chlorine gas, Cl₂. Leon had explained the purpose, processes involved and duration during the cleaning of MBRs.

Between 2.00 and 5.30 p.m., the training was continued by introducing the key parameters to be monitored during cleaning. Leon told us that transmembrane pressure (TMP) should be recorded before and after the cleaning process. We had a discussion to plan a suitable schedule for maintenance cleaning before entering the data into the PLC. He reminded us that we should always check the quantity of the chemicals to prevent running out. Later Tee asked me to check the amount of chemical carboys in the storeroom.

At 6.00 a.m., we met a man at the filter press site while he was observing the filter press. He demonstrated a simple experiment to us about the flocculation of sludge by using different types of polymer solution. Later he gave us several suggestions on the improvements of the filter press system. 

Internship in Nestlé - 23rd Jan 2017 (8am - 5pm)

Since 8.00 a.m., I prepared a simple version of the SOP of the membrane chamber filter press system by summarizing the detailed SOP version I created previously. This version is presented in the form of a process flow chart.

At 9.15 a.m., we had a daily review meeting with the operators. Tee asked me to guide the WWTP operator, Ridzuan to operate the membrane chamber filter press system as he did not attend the training session last week.

At 10.00 a.m., I briefly introduced the filter press system before guiding Ridzuan to operate the system. The sludge bags were full and we had replaced empty bags before I demonstrated the filter press operation.

Between 3.00 and 6.00 p.m., the DPRS training session was finally carried out. The first section is a simple introduction to DPRS which was conducted by Leon. He introduced and explained the function and control philosophy of each equipment while we walked around the DPRS site. Later we studied the whole DPRS with the aid of P&ID. Meanwhile, we were informed that the post-biological aeration tank is filled with the activated sludge taken from the recirculation pit.

The second section is the introduction of using the programmable logic controller (PLC) in the DPRS control room which was conducted by Maurice. A touch panel is used as an interface between the operator and the PLC, which is known as human-machine interaction (HMI). He introduced and guided us to operate the touch panel. Using the display, the control systems of DPRS can be adjusted to the desired circumstances. The functions of the display are:

(a)  displaying failure or events to the operators;

(b) providing information or parameters to the operators about the actual situation, such as pressure and flowrate; and

  (c) adjusting the parameters by entering the desired setpoints accordingly.

Internship in Nestlé - 20th Jan 2017 (8am - 5pm)

From 8.00 a.m. to 4.30 p.m., I prepared a detailed SOP for operating the membrane chamber filter press system, based on the script given during the training session. This file consists of three main sections, which are before using the filter press, using the filter press (manual and automatic mode) and discharging the sludge cake.

At 9.15 a.m., we had a daily review meeting with the operators.

Between 10.00 and 11.45 a.m., Jaclyn and I met Chow at the filter press site. Chow continued to conduct testing on filter press operation. During the operation, we observed the residual water was flowing into the raw pit. Eventually, the final product, sludge cake was drier than previous testing. I had taken several photos which to be inserted into the SOP file.

At 4.30 p.m., we had a meeting in the DPRS control room. They confirmed that a training session would be provided to us and the WWTP operators next Monday and Tuesday. Hence, I must be on the DPRS site from next Monday morning.

Besides that, we discussed the issues of clean water drainage and chemicals to be used during the MBR commissioning. Next, Istiak discussed with us the issue of sodium hydroxide (NaOH) usage for the new DAF operation. Later Tee and Fam went to the existing DAF site and discussed the issue of supplying NaOH while observing the existing NaOH tank there.

At 5.30 pm., I sent the detailed SOP of the operating filter press system to Tee. 

Typical lunch at Nestlé's canteen; CNY is around the corner~

Internship in Nestlé - 18-19th Jan 2017 (8am - 5pm)

Wednesday, 18^th Jan 2017 (8am - 5pm)

At 9.15 a.m., we had a daily review meeting with the operators as usual.

Between 10.00 a.m. and 12.30 p.m., I continued updating the FLOCs by adding the information relating to maintenance. I first read the user manual of each pump and instrument before extracting the main information into FLOCs.

Between 3.00 and 5.00 p.m., Jaclyn and I with two WWTP operators, Vasu and Desa attended a training session by Chow. This session was about the basic operation of the filter press system. It can be operated either in automatic or manual mode. Throughout the training, I fully understand the procedure of operating this system.

At 5.00 p.m., Jaclyn and I represented Fam to listen to any feedback from the person in charge of MBR commissioning. According to Leon, tomorrow they will discharge clean water from the post-biological aeration tank before pumping in the sludge from the recirculation pit. They provided several suggestions about the temporary pipeline connections.

Thursday, 19^th Jan 2017 (8am - 5pm)  

Between 8.15 and 8.45 a.m., as usual, I walked around in WWTP. Leon had informed me they could not continue their progress to pump the sludge into the new aeration tank as the pump is not suitable to be used. I passed this message to Fam in the office.

At 9.15 a.m., we had a meeting with the operators. Tee had assigned me to prepare two versions of the SOP for filter press operation, one in a simple version so that the SOP can easily be understood by the operators, and another in a detailed version.

Between 11.00 a.m. and 12.30 p.m., Jaclyn and I followed the operation procedure to operate the filter press system. Firstly we switched on the sludge transfer pump to fill the thickener tank. However, there was no sludge flow even though the diaphragm pump was turned on while the polymer solution was continuously flowing into the tank. Then I realized that along the outlet of the sludge silo, the main gate valve was closed. I quickly turned on the valve and eventually, the sludge flowed into the system. Then the thickened sludge was fed into the filter press using the feed diaphragm pump. The feeding stage would last for a few hours.

At the same time, Fam was passing by and observing the filter press operation. During the feeding stage, there was a knocking sound and he tried to detect the sound source. He also asked us why not fully open the ball valve at the outlet of the feed diaphragm pump entering the filter press.

Later he asked me a question about the reason for using diaphragm pumps throughout the sludge delivery. I answered that it is due to its reliability and durability. He agreed with me and added some points: Diaphragm pump, which is a type of positive displacement pump, is suitable for slurry fluid as compared with centrifugal pump. Therefore most of the type of pumps used in WWTP is diaphragm pump.

Diaphragm Pump (Source: AirTech)

Between 9.30 - 11.00a.m.; and between 1.30 - 4.00 p.m., I had completed updating the FLOCs by adding the information relating to the maintenance and service of each equipment. Tee had assigned me to conduct an experiment on the flocculation of sludge by polymer solution and prepare a laboratory report for the results to determine the optimum dosing of polymer to be used.

The training session and meeting in the DPRS control room have been cancelled for today.

Internship in Nestlé - 16-17th Jan 2017 (8am - 5pm)

Monday, 16^th Jan 2017 (8am - 5pm)

At 9.15 a.m., we had a daily review meeting with the operators.

At 10.00 a.m., as usual, I walked around and observed the unit operations in WWTP. Tee and the person in charge of filter press commissioning, Chow, were having a meeting at the site. Afterward, we were informed that the testing of the filter press system would be conducted by tomorrow while an operation training session for us would be held this Wednesday.

Later I revised and rechecked the material balance and calculated the parameters of WWTP generated.

At 4.00 p.m., we had a meeting in the DPRS control room. Recently the fiber membranes of MBRs are under testing procedure using clean water, in which water is recirculating between post-biological aeration tank and MBRs. Besides that, the DPRS training session is tentatively scheduled for this Thursday. Tee had requested them to provide the following information:

a)       guidelines and a checklist of water parameters to be monitored during MBR operation;

b)      a full schedule for the whole DPRS commissioning; and

c)      basic DPRS operation, including troubleshooting and maintenance schedule during the training session. 

Tuesday, 17^th Jan 2017 (8am - 5pm)

Between 8.15 and 8.45 a.m., as usual, I walked around WWTP, especially the new DAF site, the filter press site, and the DPRS site. The testing of MBR fiber membranes by water recirculation was stopped as there was water leakage at certain parts of the membranes.

At 9.15 a.m., we had a meeting with the operators. Tee informed us there are several cases relating to safety issues in Nestlé factories and again reminded us to report any hazards found in the working area as soon as possible to minimize the accident.

At 9.30 a.m., I updated the FLOCs by adding the information relating to maintenance.

Between 11.00 a.m. and 3.30 p.m., I was in WWTP while Chow was conducting the testing procedure of the membrane chamber filter press system for the first time. I took the opportunity to ask him some detailed questions to understand the operation of the filter press system. Meanwhile, I had observed throughout the operation.

At 4.00 p.m., I met Fam in the DPRS control room but Maurice and Leon were not there. Then I followed Fam to have a short discussion with the process engineer, Istiak at the new DAF construction site. He would be in charge of new DAF commissioning.

At the same time, a cassette of fiber membranes was taken out from the MBR tank by using a truck-mounted crane. Later, we saw Leon and some workers were busy checking the condition of fiber membranes. The cassette of membrane modules was immersed in a water tank. They injected the compressed air to detect the leakage parts and rearranged the modules properly. 

Internship in Nestlé - 13th Jan 2017 (8am - 5pm)

At 9.15 a.m., we had a daily review meeting with the operators.

At 9.30 a.m., after the meeting, I went back to the office to prepare the presentation for Mr. Bala’s visit.

At 10.30 a.m., Mr. Bala called me upon his arrival while waiting for me in the security office. I welcomed him and brought him to meet my supervisor, Mr. Tee. We had a discussion in the HR meeting room. First and foremost, I introduced the given tasks to be completed during my three-month internship period. Next, I presented the process flow of DPRS while showing the scribbled P&IDs to Mr. Bala. I had answered any questions asked by him relating to DPRS.

After that, Mr. Bala asked each of us several questions to understand my workplace and current progress from both sides. He also gave several comments for the enhancement of my internship experience. Unfortunately, we did not manage to have a site visit for him due to inconvenience and safety issues as several sections in WWTP are under construction. Lastly, he requested us to fill out a feedback form, individually. Afterward, Tee was busy and left earlier while Mr. Bala had a short conversation with me. He was satisfied with the opportunities received by me and the value of training in my chemical engineering study. He also was particularly interested in the P&IDs I had studied. Eventually, the visit was up to an hour.

At 4.00 p.m., we had a meeting in the DPRS control room to get any feedback from the PIC. We were informed that the ultraviolet (UV) disinfection system is ready for operation. However, Maurice suggested a flowmeter should be installed at the outlet of the UV system, right before the inlet of the RO system. He also required Tee to provide the parameters of treated water for the past four weeks, such as flow rate, COD, pH, etc. Besides that, a DPRS training course is scheduled for us next Thursday.

After the meeting, I followed Tee to get a high-density polyethylene (HDPE) carboy of sodium hypochlorite (NaClO) as requested by PIC. The purpose of using this chemical is to kill the microorganisms present in the fiber membranes before MBR operation. Later I prepared a table consisting of parameters of treated water for the past four weeks before emailing this file to Tee for checking.

Internship in Nestlé - 11-12th Jan 2017 (8am - 5pm)

Wednesday, 11^th Jan 2017 (8am - 5pm)

At 8.15 a.m., Jaclyn shared the softcopy of DPRS, the new DAF unit and the sludge dewatering system, which consists of P&ID drawings, enclosures, operational and technical description manuals. These documents would be useful for my tasks in the future.

At 8.30 a.m., I went to the filter press site and took photographs of different parts of the filter press system for my reference. There were minor constructions such as painting at this site.

At 9.15 a.m., we had a daily review meeting with the operators as usual. Tee had told me that every day at 4.00 p.m. I have to attend the meeting to listen to any updates and feedback from person in charge (PIC) of commissioning in the DPRS control room.

Later, Mr. C. M. Balaram, a senior lecturer from my university, confirmed a visit on Friday with us via email. The main purpose of this visit is to review and evaluate my performance in my internship at Nestlé. Mr. Bala has more than 30 years of industrial experience before being a lecturer in my university. He lectured me for several engineering units, such as Engineer in Society (CHE4161) and Design Project (CHE4170). He will lecture on Environmental Impact Assessment and Management Systems (ENE3608) next semester (March-May 2017).

At 4.00 p.m., Tee, Fam, Jaclyn and I had a meeting with the PIC in the DPRS control room. I observed that there are closed-circuit televisions or CCTVs for the surveillance of the two entrances of the DPRS site and the corridor between the aeration tank and MBRs. The purpose is to monitor the overflow condition from MBRs to the aeration tank when under operation. Besides, we were informed that the MLSS in MBRs would be maintained at 10000 mg/L. 

Thursday, 12^th Jan 2017 (8am - 5pm)  

At 8.15 a.m., Jaclyn added a template in the FLOC file, which lists certain parts to be maintained, the maintenance schedule and the specification of lubricating oil required for each equipment. I will prepare all the information to complete the FLOCs.

At 9.15 a.m., we had a daily review meeting with the operators as usual.

Between 10.00 a.m. and 3.30 p.m., I was performing material balance and calculating the parameters of biological treatment of existing WWTP using Microsoft Excel. During the process, I found some uncertainties and questions, even though I had revised the steps several times.

At 4.00 p.m., I attended the meeting to listen to any updates from the PIC of MBR commissioning. The cassettes of hollow fiber membranes were transported using a truck-mounted crane for installation inside the MBRs. At the same time, the floating aerator in the balance tank was faulty previously and the replacement was carried on.

Internship in Nestlé - 9-10th Jan 2017 (8am - 5pm)

Monday, 9^th Jan 2017 (8am - 5pm)

At 8.00 a.m., I compiled the experimental raw data which was obtained last Friday, using Microsoft Excel, including the photographs showing the settling of flocs in solution. I had made a simple conclusion before emailing this file to Tee.

At 9.15 a.m., we had a daily review meeting with the operators as usual.

At 10.00 a.m., I walked around in the WWTP and realized that the new DAF with a larger capacity had arrived and been installed a few days ago. The construction of roofing and installation of piping were carried on at the new DAF site. In the DPRS site, there were still several minor installations and checks in progress. At the same time, a concrete bund was built around the filter press (sludge dewatering system). Later, Jaclyn and I observed the newly installed DAF unit with its flocculation system.

Between 1.30 and 3.30 p.m., I generated a final laboratory report for the experiment as required by Tee. In this report (refer to Appendix B), the procedure, tabulation of results and discussion were clearly described, including the conclusion about the recommended dosing of the chemicals based on the experimental outcomes.

Later Fam gave us two documents of the operation manual of the new DAF unit. Tee had told us that the person in charge of the DPRS commissioning would be coming tomorrow morning.

Tuesday, 10^th Jan 2017 (8am - 5pm)

At 8.00 a.m., as usual, I walked around WWTP to observe the unit operations in the plant. Later, Tee, Fam and Jaclyn arrived at the site and I was called to meet two persons, Maurice from the Netherlands and Leon from local, who are in charge of MBR commissioning. Fam had guided them to understand the process flow of DPRS. According to Maurice, functional testing and checking of each equipment and instrument would be conducted before the commissioning stage of MBRs.

At 9.15 a.m., we had a meeting with the operators as usual. I was informed the commissioning of the sludge dewatering system would be conducted from this week onwards.

At 11.00 a.m., we met the person in charge of filter press commissioning. They started to check the electrical panel of this system.

At 2.00 p.m., to obtain the input data for generating the material balance of our existing WWTP, I went to the WWTP control room to collect water parameters which have been recorded by the operator daily since the first day of January. The aims of the recording are to monitor the characteristics of water in WWTP and as the reference for the engineering department and DOE.

At 4.00 p.m., I went to the DPRS site and noticed that there were two A1 paper-sized P&IDs pasted on the holding tank. Several parts were highlighted with different colours, indicating certain instruments or equipment had been checked mechanically, electrically and in the aspect of input/output (I/O) software operation.

Internship in Nestlé - 6th Jan 2017 (8am - 5pm)

From 8.00 a.m. to 12.25 p.m., I rearranged the registered FLOCs of DPRS equipment by following the decision made during yesterday's meeting. I had checked and updated the FLOCs before sending the file to Jaclyn.

At 9.15 a.m., we had a daily review meeting with the operators as usual.

At 11.15 a.m., Tee assigned me to experiment with coagulation and flocculation using a water sample taken from the final discharge point. He had demonstrated this experiment to me at the WWTP laboratory. He added 1.0 mL of ferric chloride (FeCl₃) coagulant solution into 500 mL of water sample and then stirred the mixture rapidly. Initially, the brown-orange microflocs were formed.

Later, he added 1.0 mL of polymer solution (flocculant), stirred and allowed the settling of larger-sized flocs formed in the solution. However, we observed that the water sample was still in light orange colour (the solution is expected to be more transparent than the freshwater sample), even much polymer solution was added. He suspected that an exceeding amount of FeCl₃ solution was added, giving this colour due to the presence of metal ions in excess.

At 2.00 – 5.15 p.m., I began my task by planning a procedure before performing the experiment. I made the observation, recorded down every single detail in my notebook and took photos. During this period, Tee came to the laboratory and asked me about the experimental outcome I had obtained so far. Then he requested me to repeat the experiment using a smaller dosing of 0.05 mL and 0.10 mL of FeCl₃ solution to obtain an optimum dosing of FeCl₃ solution as possible.

During the experiment, I wore a pair of latex gloves, especially when handling FeCl₃ solution, an oxidizing agent. I was assigned to make a laboratory report and submit it to Tee by next Monday morning.

At 5.45 p.m., Tee told me that the commissioning of DPRS would be carried out from next week onwards. I am looking forward to this project.

Internship in Nestlé - 4-5th Jan 2017 (8am - 5pm)

Wednesday, 4^th Jan 2017 (8am - 6pm)                    

At 9.15 a.m., we had a daily review meeting with the operators.

At 10.00 a.m., as usual, I went to the DPRS site to conduct pipeline tracing. The metal fencing was installed and the concrete bund was constructed around the DPRS site. The purposes are to restrict the accessibility into the site by unauthorized personnel and to provide containment for the process liquid in the event of leakage when DPRS is under operation.

At 11.00 a.m., I summarized the information and prepared a note after reading the process description manual of the existing DAF unit, which involves physical-chemical process for particle removal from industrial effluent. 

At 2.30 p.m., Jaclyn and I went to WWTP. At the same time, the waste management company was at WWTP to remove the oil layer from the balance tank. The purpose is to minimize the impact on water quality at downstream processes due to the presence of an oil layer. 

At 4.45 p.m., Tee informed me there would be an important meeting that I must attend. The meeting agenda is regarding the FLOC (functional location) registration of equipment in DPRS. The FLOC contains information of equipment such as location, maintenance data and manufacturer data, which is required for maintenance tasks to be performed.

5.00 – 6.00 p.m., Jaclyn emailed me a file regarding the master record of FLOC of DPRS and asked me to help her check the information. I emailed her with the updated FLOC once I completed this task.

Thursday, 5^th Jan 2017 (8am - 6pm)

At 8.00 a.m., I checked the FLOC sent by Jaclyn after she had added some extra equipment data into the FLOC file.

At 9.15 a.m., as usual, we had a meeting with the operators.

At 10.00 a.m., I went to the DPRS site and noticed the chemical dosing systems were installed completely. At the same time, the installation site cleanup was carried out.

At 4.15 p.m., Tee, Jaclyn and I had a meeting with Fam Hon Koon, senior project engineer, who is the person in charge of the DPRS construction project. I was asked to start the meeting by describing the Maintenance Plan I had prepared, from the beginning to the end of the DPRS process flow.

During the meeting, Fam explained and shared with me the information and knowledge based on his years of valuable practical experience. Besides that, we streamlined the FLOC registration work of DPRS equipment by categorizing several instruments into a number of FLOCs.

At 5.20 p.m., the meeting ended. Tee had informed me that tomorrow he would show me the experimental procedure of coagulation and flocculation using a water sample.

Internship in Nestlé - 3rd Jan 2017 (8am - 5pm)

At 9.15 a.m., we had a daily review meeting with the operators.

At 11.00 a.m., I met Jaclyn and WWTP operator, Ridzuan at the existing DAF unit while they were monitoring water condition in the flocculator. The flocs were unable to be produced after several sample tests.

At 2.30 p.m., I went to WWTP and observed the unit operations. I noticed that due to the outlet is constructed at a higher point, the final discharge was full of water before entering the pump pit, which is the first section of DPRS. Later I met Christ, my colleague who is in charge of electrical service and he wished to understand the process flow of DPRS. I took this opportunity to revise the DPRS study by explaining the process description and answering his questions about the DPRS. He thanked me for guiding him to understand DPRS within a short period.

At 3.15 p.m., I had a great chat with a safety personnel, Hazi. He is in charge of monitoring the construction safety.

At 3.30 p.m., Jaclyn and I observed the pipeline around the permeate tank, which is the final section of DPRS for clean water distribution. The pipeline arrangement is totally different from that shown in P&ID. We had redrawn the diagram for our own reference. Later, we went up to the top of the permeate tank to trace the source of the pipeline. I managed to observe and recognize several fittings such as air vent pipes, water pressure relief valves, pressure regulators, etc.

A system consisting of pipings and valves (taken on the same day)

At 4.50 p.m., we studied the chlorine dioxide generation and dosing system at the DPRS site. However, we did not really understand how it works, and perhaps guidance may be given by the technician in the future.