Evaluation of Communal Wastewater Treatment Plant Operating Anaerobic Baffled Reactor and Biofilter

Construction of communal Waste Water Treatment Plant, WWTP in city of Malang since 1998 but until recently had never done an evaluation the performance. Communal WWTP performance evaluation is needed to see how far the efficiency of processing result. Until now, Environmental Agency Malang City only measure effluent from WWTP Communal to know the suitability with domestic wastewater quality standards. Effluent quality data in 2014 showed value above the quality standard of domestic wastewater from East Java Governor Regulation No. 72 in 2013 for parameters BOD and COD. WWTP Communal USRI research objects are on a six (6) locations by involving the user community during the planning, construction, operation and maintenance. Technology choice of ABR followed by a biofilter reactor with the stone media proved capable of processing organic matter of BOD and COD with the removal levels respectively by 78% -99% and 71% -99%. As for the parameters of TSS, NO3 and PO4 have the ranges of removal respectively by 56% -100%, (43%) 72%, (2%) 13%. Ratio BOD and COD in influent are low and ranged from 0.22 to 0.41. From the evaluation shows that high organic matter concentrations in influent along with the HRT and operation time high will result in a higher removal level. Keyword-Communal WWTP performance, Level of removal, Ratio BOD and COD , HRT. Submission: January 10, 2016 Correction: March 14, 2016 Accepted: March 25, 2016 Doi: http://dx.doi.org/10.12777/wastech.4.1.7-12 [How to cite this article: Hendriarianti, E., and Karnaningroem, N., (2016). Evaluation of Communal Wastewater Treatment Plant Operating Anaerobic Baffled Reactor and Biofilter. Waste Technology, 4(1),7-12, doi: http://dx.doi.org/10.12777/wastech.4.1.7-12


INTRODUCTION
Wastewater management resettlement cities / regencies in Indonesia have target of access 100% [1].One option of wastewater treatment system in the residential facilities scale-city is Communal WWTP with Anaerobic Baffled Reactor (ABR) as biological treatment unit.The use of the communal system in the future consider the management of flexible, simple technology and cost effectiveness [2,3].ABR technology developed by Mc Carty, et al at Stanford University in the early 1980s [4].The flow that are up and down in the ABR cause the flow of incoming wastewater (influent) have more intensive contact with an anaerobic biomass, thereby improving processing performance.BOD decrease in ABR higher than the septic tank, which is about 70-95%.Need to include airways.For the initial operation needs 3 months to stabilize the biomass at the beginning of the process [5].
Since 1998, it has carried out the construction of communal WWTP in the city of Malang but until recently had never been done an evaluation of the performance of this reactor.Communal WWTP performance evaluation is needed to see how far the efficiency of processing is generated.Environmental Agency at Malang City (BLH kota Malang) evaluate only on the outlet quality of the Communal WWTP.Outlet quality data in 2014 showed a value above the quality standard of domestic wastewater from East Java Governor Regulation No. 72 In 2013 for the parameters BOD and COD.While the Brantas river water quality data on the location of the WWTP effluent discharge Communal showed high content of ammonia (0.13 to 1.14 mg / L) and nitrite (0.102 to 0.423 mg / L).
WWTP communal funded by USRI that become research objects are on a six (6) locations in the city of Malang by involving the user community during the planning, construction, operation and maintenance.Expected from the results of the performance evaluation Communal WWTP can provide input feasibility ABR technology as an option of domestic wastewater treatment technology in Indonesia.In addition, the performance evaluation activities Communal WWTP also be input for optimization of WWTP so generated better effluent quality and can be reused for agriculture.The benefit of the WWTP optimization providing performance solutions to problems rather than renewing the existing WWTP infrastructure that requires high cost.

MATERIALS AND METHODS
Communal WWTP performance evaluation activities as in the image below.

Figure 1. Flow diagram of WWTP Communal Activity Performance Evaluation
The description of each stage of the following activities:  4. Processing of the data to gain treatment efficiencies.5. Evaluation of the performance of the communal wastewater from treatment efficiency, BOD / COD and HRT.

RESULTS AND DISCUSSION
Overview Object Study USRI Communal WWTP located on the upstream and middle stream Brantas river in the city of Malang as in the image below.

Figure 2. Map Of WWTP Location Sampling
General overview of USRI Communal WWTP becoming object in this study as follows.Communal wastewater treatment systems in use DEWATS system consisting of a sedimentation unit for separating solids, Anaerobic Baffled Reactor for biological treatment and anaerobic filter unit as tertiary treatment.DEWATS system is a system option scale decentralized wastewater treatment in peri-urban area [6].Some of the benefits of this system is tolerant to fluctuations inflow, long-term and reliable application, low cost for operation and maintenance and has the potential for reuse.Effluent from DEWATS system applications on the object of study is still directly discharged to the river.From research performance evaluation is expected to be developed as a potential water reuse for plant and fish growing media.

Communal WWTP Evaluation Results
The result of the influent and effluent concentrations of water quality parameters COD and BOD can be seen in the chart below Of the value of biodegradation indexs that fixed increased showed high content of biodegradable organic matter in influent that potentially interfere with the processing of organic material in the wastewater.The use of ABR as anaerobic pre-treatment system and pond of stabilization with the media as a post-treatment system has been studied as the option of choice of domestic wastewater treatment technology that suitable for tropical and sub-tropical regions in developing countries [8].Technology choice of ABR followed by a filter reactor with the stone media on WWTP Communal proved capable of processing organic matter of BOD and COD with removal levels respectively by 78% -99% and 71% -99% (chart 3).As for the parameters of TSS, NO3 and PO4 have the range of removal respectively by 56% -100%, (43%) -72%, (2%) -13%. ) resulted in the level of removal of 82% with a HRT of 12 hours and the operating capacity below design capacity (66%).From the results of this evaluation shows that the high influent concentrations in line with the duration of HRT and the operation time will result in a higher removal level.This condition indicates the availability bacterial of decomposition and optimal conditions for the processing of organic material.The anaerobic bacteria are a group of bacteria metabolic consisting of microorganisms hydrolytic, fermentative, syntrophic and methanogenic which outlines the complex organic compounds in the process of anaerobic degradation [11].

Communal
Removal level that obtained is the result of processing biofilter with the stone media because the effluent was taken after the biofilter.Organic load that is too low cause biomass limited to degrade organic matter and resulting organic matter removal levels that low.Biofilter performance is highly dependent on the microbial activity.A substrate sources that constant required for the consistency and effectiveness of operations.Biofilter success depends on the growth and maintenance of biomass on the surface of the media.Three important things in understanding the mechanism of processing using a biofilter is (1) attachment of biomass, (2) The use of the substrate and the growth of biomass and (3) Sloughing of biomass.Strong attachment process and colonization of biomass depends on the influent characteristics (eg organic and concentration) and the surface properties of the filter media.A key factor in the performance of the process of biofilm formation is the amount of the growth and physical factors that affect the release of biofilm.The process of erosion, abrasion, sloughing and grazing or predation often examined and to be studied on the mechanism of release of biomass.Evaluation of biomass lost during washing the filter is very important in the operation of the filter.But previous studies showed the biomass that effectively responsible in organic matter removal is not lost during washing filter normally.Most studies show that the loss of biomass only because of the shear stress of the fluid [12].
The existence of ammonia in anaerobic degradation can be an inhibiting factor [13]. Ammonium is an important nutrient for the growth of methanogens, then the excess of free ammonia will disrupt the process of methanogenesis.Methanogenesis more sensitive to the rise in pH resulting free ammonia as shown in the reaction: Norg → NH4 + + OH -↔NH3 + H2O.The concentration of ammonia in the effluent wastewater can be seen in chart 4.

Graph 4. Ammonia Effluent
Ammonia in the effluent of communal WWTP should be treated by post treatment so can be reused.WWTP evaluation results become input for the development of wastewater treatment technologies, especially in communal scale at Malang city.Through optimization of wastewater treatment processes, will be achieved conservation of water resources.
The value of the ratio of BOD / COD WWTP Communal of the influent on the object of study ranged from 0.22 to 0.41.
From the evaluation shows that the high concentrations of organic matter in influent in line with the high of HRT and operation time will result in a higher allowance level.With the organic loading that is too low cause biomass limited to degrade organic matter and result low levels of organic material separation.The presence of ammonia in anaerobic degradation should be treated to produce biogas and nutrient-N.

1 .
Data collection and processing operations Communal WWTP comprising of operations and process design data of the Agency for Family Planning and Community Empowerment (BKBPM) Malang and User Groups and Sustainer (KPP) as manager of the Communal WWTP. 2. Sampling and analysis of influent and effluent quality parameters in any communal wastewater treatment unit that includes the concentration of BOD, COD, TSS, NO3, and PO4.Sampling of wastewater was conducted by moment sampling (grab sampling) in accordance with SNI 6989.57:2008 on Method of Wastewater Sampling.3. Analysis of the quality of wastewater samples carried out by the Water Quality Laboratory PJT I by using the following method.

Figure
Figure 3. Schematic Processing Unit Communal WWTP Communal WWTP Performance ABR is a high rate anaerobic digestion reactor.SRT separate from HRT to maximize performance of pollutants processing by anaerobic bacteria that slow [9].Reactor with high SRT will minimize the HRT so the volume load become greater.HRT of the ABR on WWTP Communal varies with the value of 12 hours, 15 hours and 26 hours.Effluent concentration of BOD and COD also varied with concentrations of 148 mgCOD / L -3921 / L, 84 mgBOD / L -1860 mgBOD / L. The strength characteristics of this waste varies.In the study of artificial wastewater treatment with low COD concentration of 300-400 mg / L resulted in the level of removal of 87.2% for HRT 24 hours and 91% for HRT 24 hours [10].WWTP Communal Mergosono operating for 3 years with a high influent COD concentration (3921 mg / L) resulted in the removal rate of 95% with a HRT 26 hours and the operating capacity exceed design capacity (121%).Whereas, for the WWTP Communal Oro-oro Dowo with the operation time 2 years and influent COD concentration is low (149 mg / L

Table 2 . General description Communal WWTP
USRI Communal WWTP operating unit use DEWATS technology with ABR processing unit and anaerobic filter with stone media.Treatment scheme can be seen on the following figure.