Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Decentralized Wastewater Treatment System (DEWATS) for        the Sta. Cruz Class AA Municipal Abattoir        A. C. Abino...
LGU recognized that with affordable but effective sanitary controls, the availability of good qualitymeat is ensured, howe...
Anaerobic Baffle ReactorThe baffle reactor forms part of the secondary anaerobic treatment which encompasses series ofcham...
Figure 2.1 Results of the analysis of BOD (mg/L) from the samples taken at the Indicator Pond ofthe Sta. Cruz DEWATSMoreov...
Table 1. Results of the analysis of effluent standard parameters from the samples taken at theIndicator Pond of the Sta. C...
Upcoming SlideShare
Loading in …5
×

Decentralized Wastewater Treatment System (DEWATS) for the Sta. Cruz Class AA Municipal Abattoir

496 views

Published on

prepared by A. C. Abino Laguna Lake Development Authority, Km. 70 Bangyas, Calauan, Laguna (E-mail: abinoazyleah@gmail.com) for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).

  • Be the first to comment

Decentralized Wastewater Treatment System (DEWATS) for the Sta. Cruz Class AA Municipal Abattoir

  1. 1. Decentralized Wastewater Treatment System (DEWATS) for the Sta. Cruz Class AA Municipal Abattoir A. C. Abino Laguna Lake Development Authority, Km. 70 Bangyas, Calauan, Laguna (E-mail: abinoazyleah@gmail.com) Abstract Wastewater from slaughterhouses is mainly composed of diluted blood, fats, suspended solids and in some cases manure. When untreated wastewater was discharged into creeks, rivers or lake, it will contribute significant volume of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) of the receiving water body at a concentration of 1100 ppm and 2200-2500 ppm, respectively. The Decentralized Wastewater System (DEWATS) is a treatment system that could separate solids and stabilized pollutants, remove toxic or other hazardous substances which are likely to distort sustainable biological cycles as well as stabilized or inactive suspended substances in order to reduce BOD, COD and other parameters within the prescribed limits set under the effluent standards for Class C waters. This wastewater system was applied to treat the effluent of the Sta. Cruz Class AA Municipal Abattoir which started to operate on September 2009. Parallel to its operation, wastewater samplings were conducted to establish and monitor system efficiency. In cognizant to the performance of the cost-effective facility, samples analyzed obtained 37.33% and 80.48% reduction of BOD and TSS, respectively, relative to the standards stipulated in DAO No. 35. Apart from the treatment of effluent, the DEWATS is equipped with gas (CH4) recovery system given that the wastewater quality is suitable for methane production. Through the operation of the DEWATS being a low-cost natural treatment processes and efficient technology for the Sta. Cruz Double AA Abattoir, the system was replicated by different LGUs within the Laguna de Bay region under the LISCOP Project as a sanitation solution to mitigate further pollution loading on the lake amidst the continuous economic growth and urbanization thereat. Keywords increasingly environmentally conscious economy; cost-effective and efficient technology; methane recoveryRECOGNIZING NEED FOR CHANGESta. Cruz is the provincial capital of Laguna which lies in the southeastern portion of the Laguna deBay Basin. Being a first class municipality and part of the economic growth corridor, theCALABARZON, its population has continued to grow tremendously due to uncontrolled in-migration from Metro Manila and other surrounding regions. These concerns have led to informalsettlements, urban sprawl, congestion and concomitantly, the growing range of environmentalissues and challenges for the Local Government Unit (LGU).Over recent decades, livestock farming was among the growing industry and economic livelihoodin the municipality of Sta. Cruz. In fact, among the towns covered by the Sta. Cruz sub-basin, itranked first in terms of the population of livestock raised annually. It has even produced bettereconomic and livelihood opportunities for the constituents of Sta. Cruz. The municipality has evenbecome one of the centers for the production of meat and meat products in the region. The LGUalso was able to generate additional revenue from the establishment and operation of a MunicipalAbattoir within the public market. However, the operation of the slaughterhouse encounteredproblems related to the management of effluents as well as compliance to environmental laws andstandards. To resolve these issues, the LGU decided to permanently close the old slaughterhouseand construct a new municipal abattoir with wastewater treatment system in Barangay Palasan. The
  2. 2. LGU recognized that with affordable but effective sanitary controls, the availability of good qualitymeat is ensured, however, spurred by an increasingly environmentally conscious economy, it hasbeen recognized that the cleanliness and sanitation of meats and other components that reach themarkets should not be made at the detriment of the environment.COMMITMENT AT WORKIn 2005, wastewater management has been identified by the key stakeholders as one of the priorityconcerns during the Laguna de Bay Watershed Environmental Action Planning (LEAP) under theWorld Bank Funded, Laguna de Bay Institutional Strengthening and Community Participation(LISCOP) Project. Through the LISCOP Project that is being implemented by the Laguna LakeDevelopment Authority (LLDA) through a loan from the World Bank and a supplemental grantfrom the Government of Netherlands, DEWATS was installed on the newly constructed Sta. CruzClass AA Abattoir. The construction of the DEWATS will ensure compliance to the DENR andLLDA effluent standards prior to their discharge into the Sta. Cruz river.DEWATS MODULESBasically, the treatment process allows the separation of solids and stabilize pollutants, removal oftoxic or other dangerous substances which are likely to distort sustainable biological cycles and theremoval of stabilized or inactive suspended substances in order to improve turbidity. The untreatedwastewater passes through series of engineered modules that involves anaerobic and aerobicprocesses to be able to achieve the standards set by the regulatory institutions of the country. Figure1.1 illustrates the perspective view and on-site photo of the DEWATS modules implemented for theSta. Cruz Class AA Municipal Abattoir. PhragmitesIP PGF AF ABR Biogas DigesterFigure 1.1 DEWATS module in its perspective illustration (left) and on-site photo (right)Biogas DigesterThe first anaerobic module is the biogas digester. Its main purpose is for the utilization andcollection of biogas which is produced by means of fermentation/digestion of slaughterhouse waste.
  3. 3. Anaerobic Baffle ReactorThe baffle reactor forms part of the secondary anaerobic treatment which encompasses series ofchamber that functions to assist the digestion of difficult degradable substances by intensifying thecontact between the incoming raw wastewater and the active biomass present in the reactor.Anaerobic FilterFilter mediums such as volcanic cinders are used in order to allow the wastewater to circulatepassing the fixed microorganisms as a treatment process. It includes treatment for non settleablesolids and dissolved solids by bringing them in close contact with a surplus of active bacterial mass.Planted Gravel FilterThis constructed wetland forms part the aerobic processes in treating the wastewater effluent. Thetreatment is done through filtration and continuous oxygen supply to the upper layers providingfavourable environment for bacteria diversity. Suspended solids and colloidal suspended solids ofthe pre-treated wastewater should be destroyed and removed before it traverses the planted gravelfilter to avert clogging and reduce the hydraulic conductivity of the filter. Phragmites (tambo) is theplant species used in the reed bed since it provides a perfect root zone filter.Indicator PondThe main function of the pond is to expose the treated wastewater to ultraviolet rays to aerobicallydegrade pollution, to remove pathogen and to monitor treated wastewater quality. Samples forlaboratory analysis are taken in this module.COST-EFFECTIVE AND EFFICIENT TECHNOLOGYWastewater effluent from a slaughterhouse has a complex composition if not properly managed cancause adverse impacts to the environment. It is stronger compared to domestic or municipalwastewater because slaughterhouse wastewater is mainly composed of diluted blood, fat, suspendedsolids and in some cases, also contains manure. When untreated wastewaters are released to waterbodies, it will contribute significant volume of Biological Oxygen Demand (BOD) and otherharmful substances that will pollute the receiving body of water. It was estimated that the BOD andCOD of influent was measured at 1100 ppm and 2200-2500 ppm, respectively.The LGU of Sta. Cruz estimated that about 240 liters of water is being used to slaughter one headof cattle and 120 liters per head of hog. However, when contaminated with blood and solids, it wasestimated to increase wastewater production by as much as 10% which is equivalent to 264 litersfor cattle and 132 liters for hogs.The treatment plant was designed to treat 30m3 (daily peak quantity) of wastewater produced fromthe abattoir. Likewise, the system has been customized to meet the effluent standards for Class Cinland waters specifically for New/Proposed Industry (TSS<70 mg/L and BOD5<50 mg/L) asprescribed under DAO No. 35 or the Revised Effluent Regulations of 1990. The facility started tooperate on September 2009. Parallel to its operation, wastewater samplings were conducted toestablish and monitor system efficiency. Based on the results of the analyses of six (6) wastewatersamplings, BOD ranges only from 19mg/L to 40mg/L relative to the standard BOD limit of 50mg/Lwhich is illustrated in Figure 2.1.
  4. 4. Figure 2.1 Results of the analysis of BOD (mg/L) from the samples taken at the Indicator Pond ofthe Sta. Cruz DEWATSMoreover, findings for the TSS sampling revealed that the sound operation of the engineeredtreatment facility which obtained readings within the array of 10mg/L to 19mg/L, is significantlylower than the 70mg/L maximum allowable effluent standard. Figure 2.2 shows the results of thesix (6) samplings conducted.Figure 2.2 Results of the analysis of TSS (mg/L) from the samples taken at the Indicator Pond ofthe Sta. Cruz DEWATSIn cognizant to the performance of the cost-effective facility, samples analyzed obtained 37.33%and 80.48% reduction of BOD and TSS, respectively, relative to the standards stipulated in DAONo. 35. Furthermore, the law vested the LLDA with regulatory functions over the Laguna de Bayregion, which encompasses the municipality of Sta. Cruz traversed by a major tributary riversystem, Sta. Cruz river, that flows to Laguna de Bay. Add to the construction of the DEWATS forthe Sta. Cruz Class AA Abattoir under the LISCOP Project which is implemented by the LLDA. Afurther wastewater sampling was undertaken by the Environmental and Social Safeguards, a groupalso forms part LISCOP Project, which the results tabulated below likewise show that all of theeffluent standard parameters were met by the treated effluent.
  5. 5. Table 1. Results of the analysis of effluent standard parameters from the samples taken at theIndicator Pond of the Sta. Cruz DEWATSDeterminands Laboratory Sample Effluent StandardpH 7.4 6.5 - 9.0TSS, mg/L 9 70BOD, mg/L 10 50Oil/grease, mg/L 5 5Apart from the treatment of effluent, the project had the potential to avert the emissions of methane,a greenhouse gas. The treatment facility is equipped with gas (CH4) recovery system given that thewastewater quality is suitable for methane production. Based on Philippine’s climatic conditionsand performance of the DEWATS biogas digester, each biogas digester is designed to treat amaximum of 17 m3 of wastewater discharged daily with an estimated biogas production of 5.36m3/day which is also equivalent to 0.22 LPG per day. Considering such data, it is thereforecalculated that through methane capture and combustion, the facility is able to save almostPhp3,000.00 from the purchase of LPG per month of operation. The methane captured was used bythe butchers for cooking which in the long run deemed to be used for the operation of theslaughterhouse through a gas pipeline from the biogas digester to the boiling area.SETTING THE BENCHMARK AND ADVANCING SUSTAINABILITYThe intended beneficiaries of the project, primarily, are the residents of Sta. Cruz, Laguna.However, since the Sta. Cruz slaughterhouse is the only slaughterhouse within reach of sometowns, residents of nearby LGUs stand to benefit since with cleaner production from theslaughterhouse as well as the realization of its environmental and socio-economic impacts, thepossibility of interruptions from environmental officials become less probable.Through the operation of the DEWATS being a low-cost natural treatment processes and efficienttechnology for the Sta. Cruz Double AA Abattoir, the system was adopted/replicated by differentLGUs within the Laguna de Bay region under the LISCOP Project as a sanitation solution tomitigate further pollution loading on the lake. However, depending on the success of the wasteminimization techniques and the extent to which the plant will modify practices and someequipment water usage, and consequently wastewater production can be reduced from 25% to asmuch as 41%. Together, the facility ensure that the operations of the slaughterhouse will besustainable and the environmental impact on the Laguna de Bay basin will be diminished.ReferencesBNS - BORDA (Basic Needs Services Philippines Inc. in partnership with Bremen Overseas Research and Development Association). (2008). Operation & Maintenance Guideline of Decentralized Wastewater Treatment Systems for Sta. Cruz, Laguna Slaughterhouse. 7-9.LLDA, Tetra Tech EM. (2005) Feasibility Study Report of the Wastewater Treatment Facility for the Municipal Slaughterhouse of Sta. Cruz, Laguna. LLDA, Pasig City, Philippines.

×