Key performance indicators (KPIs) comparison of food chain reactor and conventional oxidation ditch technology in industrial waste treatment

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Introduction
The availability of clean water resources is increasingly gaining the attention of the global community [1] and has become one of the important issues in the Sustainable Development Goals (SDGs) Summit in September 25th, 2019 in New York.This is also an important concern for the people of Indonesia, that conservation of natural resources is still limited and has not been properly handled, there are still many water pollution, both surface water pollution and underground water pollution.In general, the causes of water pollution caused by humans are grouped into 2 classes of namely those originating from domestic activities and those originating from industry.This study aims to discuss industrial wastewater with a case study of the Jababeka industrial estate in Cikarang.General schematic representation of a WWTP with the various stages [2] Wastewater treatment technology can be done with the principles of physical, chemical and biological treatment [3].The principle of treating wastewater is conservatively classified as primary treatment for physical treatment, secondary treatment for chemical and biological treatment, and tertiary treatment for treatment with membrane technology and advanced oxidation [4].However, in the further development of wastewater treatment technology, the classification is not too rigid, because of the cross-group combination which then produces new modern technology.
In this study, a discussion was made about biological industrial wastewater treatment.Basically wastewater treatment can be done with aerobic anaerobically principles for high levels of BOD (Biochemical Oxygen Demand), while for wastewater with relatively low to moderate levels generally use aerobic biology principles [3].There are several types of wastewater treatment technology by aerobic biological oxidation, including the activated sludge process, aeration tank, aerated lagoon, sequence batch reactor, trickling filter, rotating bio contactor, and the combination and further development of these process system.According to types of media for growing aerobic microorganisms, an aerobic biological treatment processing can be classified as suspended growth process and attached growth process [3].Mostly urban water treatment in Indonesia is a biological process basis, it may be caused by cost consideration [5], for example rectangular aeration systems in the EJIP (East Jakarta Industrial Estate park), Sequence Batch Reactor (SBR) systems in industrial areas Bukit Indah, and the oxidation ditch system at Jababeka Industrial Estate.
In biological process, Increasing the growth of microorganisms can be further developed by increasing the surface area of the media thereby increasing the number of microorganisms that can grow on the media.This means that at the same Food and Mass (F/M) ratio, the efficiency of the number of pollutants that can be processed increases [6].The process of treating wastewater with aerobic biological oxidation is quite attractive because its operations and maintenance costs are relatively lower than chemical treatment.However, this treatment requires relatively high energy and cost associated with hazardouse sludge disposal.
Food Chain Reactor (FCR is one of the relatively newly developed technologies, a current technology development of this process was combining natural plants with engineered media as a botanical garden is placed on top of the Intergrated Fixed-Film Activated Sludge (IFAS) reactors, with plant roots penetrating into the reactors [7].The plants used are mostly tropical plants, so the opportunity for the application of this technology in Indonesia is very interesting.
The IFAS is an alternative cost savings with process to conventional facilities.It means alternative for upgrading existing wastewater treatment plants to nitrification and even more denitrification, and reducing tank volume means lower costs and reduced site utilization [6].Integrated Fixed-Film Activated Sludge (IFAS) process is a reasonable approach technology to upgrade the existing wastewater treatment plant that more efficiency can be achieved [8].With the application of FCR technology, it will get the opportunity to reduce energy use, decrease the production of hazardous sludge (Toxic Material), improve the quality of process results by increasing the efficiency of BOD, COD and organic nitrogen levels, as well as improving the aesthetics of Wastewater Treatment Plant (WWTP).

Research Framework
The frame work applied in this study are: reference review of key performance indicator for controlling waste water treatment process by oxidation ditch and IFAS; Collect secondary data at WWTP of Jabababeka Industrial Estate with The key parameters and key performance indicators (KPIs) of WWTP [2], in the secondary treatment : kWh/kg COD removed , kWh/kg NH 4 removed , kWh/kg P chemicals removed , kWh/kg TN removed.In the tertiary and advance treatment : kWh/kg TSS removed , kWh/log reduction (for pathogen removal), kWh/model compound such hazardous pollutant removal.As the counteract of the negative impacts of the horizontal velocity (0.25 to 0.6 m/s) on the nitrogen removal processes in oxidation ditch, it was recommended to using air diffusers and flow recirculating pumps (boosters) instead of mechanical aerators for maintaining robust operation of the plant and saving energy [15].In the orbal oxidation ditch , nitrogen removal efficiency depended on the degree of nitrification and denitrification in the outer channel, which was the largest contributor for TN removal .When DO was as low as about 0.2 mg/L in the outer channel, the highest TN removal efficiency of 75% was obtained [14].The bacterial community sharply changed during the startup period (over 100 days).Proteobacteria (accounting for 26.3%-48.4%)was the most dominant bacterial phylum in the OD system, but its relative abundance declined nearly 40% during the startup process [13].
According to Krejny, 2015 [16], wastewater KPIs of Wastewater Treatment Plant [17].A mathematical model and pilot testing to performing carbon oxidation-nitrification, denitrification and settling was revealed that operational cycles which conducted in the range (120 -400 min), only one (220 min-nitrification: 120 min/ denitrification : 100 min), met fully the nitrogen's effluent criteria and minimum energy consumption [18].From research that conduct model of Computational Fluid Dynamic (CFD) simulation showed that The oxidation ditch treatment performance is influenced by the hydraulic and physical aspects [5].The summary of Key Performance Indicators references of activate sludge system in aeration tank and oxidation from references can be seen in Table 1. 4 Key Performance Indicator of IFAS (Integrated Fixed-Film Activated Sludge) and FCR (Food Chain Reactor) Process

IFAS Review of references
IFAS process is recommended as a comfortable and efficient upgrade for improving the efficiencies of an existing low performing WWTP [8].It considers that IFAS process can reach effluent standard even has many complex problems in maintenance.IFAS also able to handle varying hydraulic loading, organic loading, increasing influent flow, stressing effluent standards, low temperatures or loss of biomass.It can handle shock loads, extreme stress situations, temperature variations and various characteristics of raw wastewater.As long as the system is well maintained, IFAS process can work efficiently for long time without any significant problems.
BOD5, COD, and TSS were 85.24, 92.52 and 90.21%, respectively; In an organic loading of 0.44 gCOD/L.d, the best removal efficiencies of Total Nitrogen (TN) and Total Phosphorus (TP) were 89.60 and 86.67%, respectively [20].There was no significant difference in nitrification between Activated Sludge (AS) and IFAS systems by Enterobacter aerogenes microbes in both AS and IFAS system if the systems were properly operated.The study revealed that E. aerogenes could be enhanced with IFAS technology to complete heterotrophic nitrification with the removal efficiency of 100% [21].In IFAS process, the suspended-growth and attached-growth biomasses worked together to perform stable COD, NH4.-N and TN removal efficiencies even during a high pollutant load period [22].

FCR Review of references
A diverse biology was created by the interaction of enzymes and various organic acids from the plant roots to the bio-media.This biology system leading to increased process stability, less sludge production and lower energy demand when compared to conservative activated sludge plants.And the sewage treatment facility appearances like a botanical garden [7].The natural plants actually do not degrade the wastewater, but provide nutrients, organic acids and enzymes that create a highly diverse biology within the plant roots and IFAS bio modules.[7].FCR is much more dense bio-film is created, when compared to other IFAS systems or MBBR processes [7].ORGANICA ecological treatment technology, as an application of FCR system which combining the latest and the conventional wastewater treatment technology [1].

Key Performance Indicator Comparison Between OD and FCR
Comparing current KPIs of FCR system in Jababeka WWTP with previous OD system showed that by Organica FCR system, the requirement parameters is less to be controlled, and simpler process of monitoring measurement which few of parameters were monitored by on line system.In FCR system not required to control of SRT, RAS, SVI, MLSS.As the simpler operation controll, human resources can be more efficient in process monitoring and laboratory works.Evenmore less sludge generation was the significant advantage since increasing efficiency in human resources , chemicals, and electricity consumption of Belt Filter operations and maintenances, also sludge disposal cost spent to the licenced company.The KPIs comparison between AS and FCR is summarized in Table 3. Need RAS system RAS system is not necessary * Source: [1], [3], [7] and log sheet operation data of WWTP2 Jababeka

Conclusions
From the literature review and case study of oxidation process and FCR process in Jababeka WWTP-2 Cikarang, it can be known that the KPI's of oxidation ditch as the activated process were flow rate (m 3 /day), energy consumption (kWh/m 3 wastewater), Solid Retention Time (SRT), F/M ratio, oxygen supply (kgO 2 /m 3 ) wastewater, %-efficiency removal of COD, BOD, TSS, NH 3 , TKN, NO 2 , heavy metals.

Fig 1 .
Fig 1.General schematic representation of a WWTP with the various stages [2]

Fig 2 .
Fig 2. Appearance of WWTP using conventional oxidation ditch (a) and WWTP after with Organica-FCR technology (b) source: Documentation of Jababeka

Fig 3 .
Fig 3. Research framework of KPIs comparison FCR vs OD aeration basin system including M & E expense per month, Aeration kWh per pound of cBOD treated per month, kWh per pound of cBOD treated per month, % Emergency Maintenance work per month, Pounds of disinfection chemicals per MG per month, kWh per MG pumped at Pre-Treatment (PTP), Pounds of ferric chloride per pounds of Total, Phosphorus removed per month, Biosolids costs per month (pressing + disposal), kWh per pound of ammonia treated per month and kWh per pound of TSS treated per month.To study of the behavior of wastewater treatment process can be projected by the dynamic mathematical modelling as it provides more accurate projection within the limited time frame at a reducing certain parameter.Cost and time availability is the consideration of limited parameters measurement of in
Fig 4 is the typical of FCR process flow diagram.

Table 1
Key Performace Indicators References of Activated Sludge and Oxidation Ditch System

Table 3 .
KPIs comparison between AS and FCR *