ebook ipal diagram alir.pdf

TatyAlfiah/Minggu, 22 September 2013Hlm - 1

Mata Kulia Desain Instalasi Pengolah Air Limbah (IPAL)Kode MK / Sks / Smtr 1309701 / 4 sks / VIIProgram Studi Teknik Lingkungan

Fakultas Teknik Sipil dan PerencanaanInstitut Teknologi Adhi Tama Surabaya [ITATS}

Dosen Taty Alfiah, ST.MT.

Diagram Alir IPAL





Diagram Alir IPAL





Diagram Alir IPAL


Diagram alir pengolahan limbah, adalah gambaran dari urutan / tahapan pengolahanlimbah cair dalam suatu IPAL.

Secara garis umum, tahapan pengolahan limbah cair secara konventional adalah sebagaiberikut:

pengolahan pendahuluan / Preliminary Treatment (bila diperlukan, rancu denganpengolahan pertama)

pengolahan pertama / Primary treatment (pengolahan fisik, untuk mengilangkanmateri anorganik)

pengolahan sekunder / secondary treatment (merupakan pengolahan biologis,memanfaatkan mikroorganisme. Bertujuan untuk menurunkan materi organicdalam limbah cair.)

pengolahan lumpur / sludge treatment / solid handling (lumpur yang mengandungbanyak mikroorganisme, harus dimatikan sebelum dibuang)

pengolahan tersier / Tertiary and/or advanced wastewater treatment (apabilamasih diperlukan, untuk menurunkan konsentrasi kontaminan yang masih ada,misal kadar Nitrat, Phosphat)

Bacaan tambahanConventional wastewater treatment consists of a combination of physical, chemical, andbiological processes and operations to remove solids, organic matter and, sometimes,nutrients from wastewater. General terms used to describe different degrees oftreatment, in order of increasing treatment level, are preliminary, primary, secondary,and tertiary and/or advanced wastewater treatment.

Preliminary Treatment






















During Preliminary Treatment, the incoming raw sewage, or influent, is strained toremoved all large objects that make their way into the sewer system. These objects canbe anything from rags and sticks to toys, cans and even snakes. Generally bar screens,which come in a variety of shapes and sizes, are used to remove the items. The influentflows across these screens, objects catch on the screens, are raised out of the water andare then raked (either mechanically or manually) off the screens.Another component of Preliminary Treatment is the grit channel where the velocity of theincoming wastewater is carefully controlled to allow sand, grit, and stones to settle to thebottom of the channel while keeping the majority of the suspended organic material inthe water column. The grit is removed from the channel, added to the larger objectsremoved by the bar screens, and taken to the landfill for disposal.Preliminary Treatment is vital for preventing damage to pumps and other equipment inthe remaining treatment stages.

Primary treatmentThe objective of primary treatment is the removal of settleable organic and inorganicsolids by sedimentation, and the removal of materials that will float (scum) by skimming.Approximately 25 to 50% of the incoming biochemical oxygen demand (BOD5), 50 to 70%of the total suspended solids (SS), and 65% of the oil and grease are removed duringprimary treatment. Some organic nitrogen, organic phosphorus, and heavy metalsassociated with solids are also removed during primary sedimentation but colloidal anddissolved constituents are not affected. The effluent from primary sedimentation units isreferred to as primary effluent.Many plants have a sedimentation stage where the sewage is allowed to pass slowlythrough large tanks, commonly called primary clarifiers or primary sedimentation tanks.The tanks are large enough that sludge can settle and floating material such as grease andoils can rise to the surface and be skimmed off. The main purpose of primary treatmentis to produce both a generally homogeneous liquid capable of being treated biologically








and a sludge that can be separately treated or processed. Primary clarifiers are usuallyequipped with mechanically driven scrapers that continually drive the collected sludgetowards a hopper in the base of the tank from where it can be pumped to further sludgetreatment stages. The clarified water flows on to the next step of treatment.

Secondary treatmentThe objective of secondary treatment is the further treatment of the effluent fromprimary treatment to remove the residual organics and suspended solids. In most cases,secondary treatment follows primary treatment and involves the removal ofbiodegradable dissolved and colloidal organic matter using aerobic biological treatmentprocesses. Aerobic biological treatment (see Box) is performed in the presence of oxygenby aerobic microorganisms (principally bacteria) that metabolize the organic matter in thewastewater, thereby producing more microorganisms and inorganic end-products(principally CO2, NH3, and H2O). Several aerobic biological processes are used forsecondary treatment differing primarily in the manner in which oxygen is supplied to themicroorganisms and in the rate at which organisms metabolize the organic matter.High-rate biological processes are characterized by relatively small reactor volumes andhigh concentrations of microorganisms compared with low rate processes. Consequently,the growth rate of new organisms is much greater in high-rate systems because of thewell controlled environment. The microorganisms must be separated from the treatedwastewater by sedimentation to produce clarified secondary effluent. The sedimentationtanks used in secondary treatment, often referred to as secondary clarifiers, operate inthe same basic manner as the primary clarifiers described previously. The biological solidsremoved during secondary sedimentation, called secondary or biological sludge, arenormally combined with primary sludge for sludge processing.Secondary treatment processes can remove up to 90% of the organic matter inwastewater by using biological treatment processes. The two most commonconventional methods used to achieve secondary treatment are attached growthprocesses and suspended growth processes.

Attached Growth Processes In attached growth (or fixed film) precesses, bacteria,algae, fungi and other microorganisms grow and multiply on the surface of stoneor plastic media, forming a microbial growth or slime layer (biomass) on themedia. Wastewater passes over the media along with air to provide oxygen, andthe bacteria consume most of the organic matter in the wastewater as food.










Attached growth process units include trickling filters, biotowers, and rotatingbiological contactors.

Suspended Growth Processes In suspended growth processes, the microbialgrowth is suspended in an aerated water mixture where the air is pumped in, orthe water is agitated sufficiently to allow oxygen transfer. The suspended growthprocess speeds up the work of aerobic bacteria and other microorganisms thatbreak down the organic matter in the sewage by providing a rich aerobicenvironmnet where the microorganisms supsended in the wastewater can workmore efficiently. In the aeration tank, wastewater is vigorously mixed with air andmicroorganisms acclimated to the wastewater in a suspension for several hours.This allows the bacteria and other microorganisms to break down the organicmatter in the wastewater. Suspended growth process units include variations ofactivated sludge, oxidation ditches and sequencing batch reactors.

After biological treatment, the water is pumped to secondary clarifiers where any leftoversolids and the microorganisms sink to the bottom. These solids are handled separatelyfrom the supernatant which continues on to disinfection.

Solids HandlingPrimary treatment and secondary biological processes concentrate waste organics intoa sludge. Methods for processing raw sludge include anaerobic digestion and mechanicaldewatering by either belt-filter pressing or centrifugation. Conventional methods of












disposal are apllication as a fertilizer or soil conditioner on agricultural land, landfilling in adedicated disposal site, or codisposal with municipal solid waste

Tertiary and/or advanced treatmentTertiary and/or advanced wastewater treatment is employed when specific wastewaterconstituents which cannot be removed by secondary treatment must be removed. Asshown in Figure 3, individual treatment processes are necessary to remove nitrogen,phosphorus, additional suspended solids, refractory organics, heavy metals and dissolvedsolids. Because advanced treatment usually follows high-rate secondary treatment, it issometimes referred to as tertiary treatment. However, advanced treatment processes aresometimes combined with primary or secondary treatment (e.g., chemical addition toprimary clarifiers or aeration basins to remove phosphorus) or used in place of secondarytreatment (e.g., overland flow treatment of primary effluent).


Terdapat beberapa pertimbangan dalam menentukan diagram alir, diantaranya : karakteristik limbah menentukan tingkat pengolahan limbah yang diperlukan

dengan memperhatikan sumber limbah peraturan berlaku baik effluent standard maupun stream standard owner/pemilik IPAL : perlu memperhatikan kemampuan biaya desain, konstruksi,

operasional dan pemeliharaan. Selian itu juga tenaga yang diperlukan untukmengoperasikan IPAL, baik operator maupun tenaga ahli

pemilihan proses pengolahan , meliputi pertimbangan teoritis, serta permasalhandi lapangan

topografi, area tersedia : menentukan profil hidrolik. Diupayakan aliran secaragrafitasi, meminimalkan kebutuhan pompa yang akan menambah biaya. Selain itu,luasan lahan sebaiknya memungkinkan bila suatu saat diperlukan pengembanganIPAL. Tebutuhan area termasuk zona buffer, penyimpanan sementara lumpur yangdihasilkan.

rencana disposal efluen maupun lumpur. Efluen IPAL akan dibuang dimana,apakah dapat mengganggu ekosistem alami yang ada ? bagaimana kualitas dankuantitas lumpur yang dihasilkan. Bagaimana rencana pembuangan maupunpemanfaatkannya menjadi pertimbangan.

aspek pembiayaan : sejak mulai konstruksi hingga OM, meliputi OM:tenaga, energibhn kimia. Oleh karena itu diperlukan perbandingan beberapa alternatif diagramalir

kesesuaian fasilitas existing : sedapat mungkin pembangunan IPAL baru sesuaidengan system pengelolaan limbah yang telah ada di sekitarnya.

aspek lingkungan, misalnya jarak dengan lingkungan terbangun sekitar, apakahmengganggu. Mungkin diperlukan zona buffer, untuk mereduksi baud an bising,memenuhi aspek estetika.

Contoh-contoh diagram alir pengolahan limbah cair secara konventional (standard)adalah sebagai berikut :

ebook ipal diagram alir.pdf

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