intermittent aeration
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2022 ◽  
Vol 139 ◽  
pp. 309-320
Author(s):  
Yi-Xuan Chu ◽  
Jing Wang ◽  
Lei Jiang ◽  
Guangming Tian ◽  
Ruo He

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 229
Author(s):  
Sabin Pathak ◽  
Shuai Wang ◽  
Eshetu Janka

Removing ammonium via the partial nitritation anammox (PNA) process has been widely applied because of its cost and energy effectiveness. However, the first stage of PNA, partial nitritation, is hard to implement practically due to the challenging suppression of nitrate oxidizing bacteria (NOB) and should be achieved in the anammox environment to extend it to one stage PNA. Hence, this article evaluates different techniques, such as the combination of low dissolve oxygen (DO) and high free ammonia (FA), and the intermittent aeration cycle to achieve partial nitritation in an anammox start-up environment. For this purpose, a 10.5 L lab-scale moving bed biofilm reactor was set up and fed with synthetic wastewater and the transformation of influent ammonium into nitrate and nitrite was measured. The results showed that, despite applying low DO and higher free ammonia than the inhibition range of NOB, the nitrate production rate (NPR) was consistently higher than the nitrite accumulation rate (NAR), signifying no sufficient NOB suppression, partial nitritation under continuous aeration and up to a 0.27 gN/m2.d surface ammonium loading rate (SALR). Higher SALR than 0.27 gN/m2.d could result in partial nitritation since nitrogen compounds transformation was closer to partial nitritation when the reactor was subjected to 0.27 gN/m2.d rather than 0.14 gN/m2.d. Lifting up the SALR, on the other hand, results in a bad anammox environment and cannot prolong it to one-stage PNA. An intermittent aeration cycle with four different cycle lengths sets, obtained by monitoring nitrogen compound transformation, was, therefore, applied to the reactor. The relatively shorter aerobic length of 10 min ON and 30 OFF intermittent aeration cycle with 0.5 mg/L aerated DO was successful in achieving the partial nitritation with NPR, NAR, and ammonium removal efficiency (ARE) values of 17%, 78%, and 37%, respectively, showing that shorter aerated length suppresses NOB to a high degree due to less available time for NOB after oxygen starvation.


Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 72
Author(s):  
Olga Zajac ◽  
Monika Zubrowska-Sudol ◽  
Slawomir Ciesielski ◽  
Martyna Godzieba

The purpose of the study was to analyse the impact of aeration strategies defined by the changes in the duration of aerated sub-phases, the ratio between non-aerated and aerated sub-phase times (R), and dissolved oxygen concentrations (DO) on the suppression of nitrite-oxidizing bacteria (NOB) in activated sludge and biofilm developing in a hybrid reactor with nitrification/denitrification. The primary factor causing NOB suppression both in biofilm and in activated sludge was an increase in the R-value (from 0 to 1/4 and from 1/4 to 1/3). After reducing the DO from 3 to 2 mg O2/L, there were no changes in the frequency of NOB occurrence, and no reduction in the nitrite oxidation rate was recorded. The abundance of Comammox bacteria was considerably affected by the change from continuous to intermittent aeration. Activated sludge showed a substantial increase in the quantity of clade A and B, whereas the quantity considerably decreased in biofilm.


2021 ◽  
Vol 20 (1) ◽  
pp. 127-138
Author(s):  
Hafasatya Maharani Putri ◽  
Sri Puji Saraswati ◽  
Johan Syafri Mahathir

Sebuah Instalasi Pengolahan Air Limbah (IPAL) di asrama mahasiswi UGM, Yogyakarta memiliki unit reaktor yang terdiri dari ekualisasi, aerasi 1, aerasi 2 dan clarifier dengan proses aerasi secara intermiten menggunakan Microbubble Generator (MBG) dengan fase aerasi dan tanpa aerasi masing-masing selama 15 menit. IPAL tersebut dibangun sebagai upaya dalam memenuhi standar Green Building bagi bangunan lama asrama di UGM untuk mengolah air limbah grey water. Hasil olahan air limbah akan dimanfaatkan di lingkungan asrama. Selama 208 hari beroperasi, kajian mengenai performa IPAL belum pernah dilakukan. Oleh karena itu, diperlukan kajian untuk mengetahui performa dan konsumsi energi pada IPAL dalam menyisihkan parameter pencemar berupa COD, nitrogen dan fosfat. Kajian dilakukan selama 81 hari pengamatan dengan menguji parameter kualitas air limbah pada setiap unit pengolahan. Parameter COD dan amonia telah memenuhi baku mutu Peraturan Menteri Lingkungan Hidup dan Kehutanan No. 68 Tahun 2016 tentang Baku Mutu Air Limbah Domestik, sedangkan parameter fosfat masih belum memenuhi baku mutu Peraturan Daerah D.I.Y. No.7 Tahun 2016 mengenai kegiatan IPAL Komunal. Hasil pengamatan pada performa IPAL, menunjukkan kedua tangki aerasi memiliki performa yang hampir sama, namun keberadaan tangki aerasi 2 tidak memiliki pengaruh yang signifikan dalam menyisihkan parameter pencemar. Pada tangki aerasi 1, efisiensi penyisihan COD mencapai rata-rata sebesar 73,6±17,46%, penyisihan PO4-P sebesar 39,12±14,96%, penyisihan total nitrogen sebesar 56,15±19,6%, efisiensi nitrifikasi sebesar 73,1±20.07% dan efisiensi denitrifikasi sebesar 61,72±27,48%. Total konsumsi energi pada IPAL dengan proses aerasi intermiten, dengan debit rerata 537,84 l/hari sebesar 14,12 kWh/m3 dan biaya sebesar Rp. 20.414/m3. Urutan konsumsi energi terbesar adalah penyisihan fosfat sebesar 5,10 kWh/gPO4-P, kemudian penyisihan amonia sebesar 1,79 kWh/gNH3-N, penyisihan TN sebesar 1,95 kWh/gTN dan penyisihan COD sebesar 0,45 kWh/gCOD. ABSTRACTA Wastewater Treatment Plant (WWTP) in the student dormitory of UGM, Yogyakarta has a reactor unit consists of an equalization, aeration 1, aeration 2, and clarifier with intermittent aeration process using a Microbubble Generator (MBG) with or without aeration for 15 minutes each. The WWTP was built as an effort to meet the Green Building standards for the old dormitory at UGM to make better process of grey water. The processed wastewater will be used for the dormitory environment. Operated for 208 days, there was no former studies for the WWTP.  Therefore, a study is needed to determine performance and energy consumption of the WWTP in removing pollutant parameters consisting of COD, nitrogen and phosphate. The study was carried out for 81 days of observation by testing the wastewater quality parameters in each treatment unit. COD and ammonia parameters have met the quality standards of the Regulation of the Minister of Environment and Forestry No. 68 of 2016 concerning Domestic Wastewater Quality Standards, while phosphate doesn’t meet the quality standards of Regional Regulation D.I.Y. No. 7 of 2016 concerning Communal WWTP Activities. Results shows the performance from two aeration tanks are almost the same, but the existence of aeration tank 2 doesn’t have a significant effect. The results in aeration tank 1 showed the COD removal efficiency reached an average of 73.6±17.46%, PO4-P removal 39.12±14.96%, total nitrogen removal 56.15±19.6%, the nitrification efficiency 73.1±20.07%  the denitrification efficiency 61.72±27.48%. The total energy consumption with intermittent aeration process with an average discharge of 537.84 l/day is 14.12 kWh/m3 and a cost of Rp. 20,414/m3 with the largest energy use being phosphate removal at 5.10 kWh/gPO4-P, then ammonia removal at 1.79 kWh/gNH3-N, TN removal at 1.95 kWh/gTN and COD removal at 0.45 kWh/gCOD.


2021 ◽  
Vol 20 (1) ◽  
pp. 102-114
Author(s):  
Afifah Munfaridah ◽  
Sri Puji Saraswati ◽  
Johan Syafri Mahathir

Sebuah instalasi pengolahan air limbah (IPAL) dibangun untuk mengolah air limbah greywater dan blackwater dari toilet dan kamar mandi umum Wisdom Park UGM yang terletak di Dusun Kuningan, Catur Tunggal, Sleman, Daerah Istimewa Yogyakarta. Unit reaktor proses IPAL tersebut terdiri dari sedimentasi, ekualisasi, aerasi 1, aerasi 2 dan secondary clarifier dengan sistem pengolahan berupa aerasi intermitten dan aerasi kontinyu dengan menggunakan Microbubble Generator (MBG) dan blower. Saat ini belum pernah dilakukan kajian terkait efektivitas sistem proses biologi pada IPAL dalam menurunkan kandungan organik dan nitrogen air limbah. Suatu sistem aerasi intermitten diaplikasikan dengan tujuan untuk mendegradasi kandungan organik dan nitrogen yang terkandung dalam air limbah, juga dapat meningkatkan dan meratakan suplai oksigen sehingga kemampuan penyerapan oksigen menjadi lebih besar. Evaluasi IPAL dilakukan selama 82 hari pengamatan dengan parameter air limbah yang diujikan terdiri dari COD, NH3-N, NO3-N, NO2-N, dan PO4-P yang nantinya akan dibandingkan dengan PerMenLHK No 68 Tahun 2016 tentang Baku Mutu Air Limbah Domestik. Hasil performa removal kontaminan di tangki aerasi 1 dan tangki aerasi 2 tidak jauh berbeda, sehingga menunjukkan bahwa pengolahan di tangki aerasi 2 tidak begitu efektif. Pada tangki aerasi 1 rerata removal COD sebesar 73,97±17,65%, removal PO4-P sebesar 53,31±13,72%, removal total nitrogen sebesar 1,57±164,29%, efisiensi nitrifikasi sebesar 82,26±16,47% dan efisiensi denitrifikasi sebesar -66,4±373,37%. Sedangkan, total konsumsi energi yang dibutuhkan untuk pengolahan air limbah di IPAL dengan debit rerata 82,06 l/hari sebesar 43,13 kWh/m3 dan biaya sebesar Rp 62.326,00/m3. Dengan konsumsi energi terbesar dihasilkan untuk peyisihan fosfat yaitu 2,99 kWh/gPO4-P, penyisihan total nitrogen sebesar 1,33 kWh/gTN, penyisihan ammonia sebesar 0,88 kWh/gNH3-N, dan penyisihan COD sebesar 0,7 kWh/gCOD. ABSTRACTA wastewater treatment plant (WWTP) was built to treat greywater and blackwater from the public toilets and bathrooms of Wisdom Park UGM located in Dusun Kuningan, Catur Tunggal, Sleman, Special Region of Yogyakarta. The WWTP process reactor unit consists of sedimentation, equalization, aeration 1, aeration 2 and secondary clarifier with a processing system in the form of intermittent aeration and continuous aeration using a Microbubble Generator (MBG) and a blower. Currently, no study has been conducted regarding the effectiveness of the biological process system in WWTPs in reducing the organic and nitrogen content of wastewater. An intermittent aeration system is applied with the aim of degrading organic and nitrogen content contained in wastewater, as well as increasing and leveling oxygen supply so that oxygen absorption capacity becomes greater. The WWTP evaluation was carried out for 82 days of observation with the tested wastewater parameters consisting of COD, NH3-N, NO3-N, NO2-N, and PO4-P which will later be compared with the Minister of Environment and Forestry's Regulation No. 68, 2016 on Domestic Wastewater Quality Standards. The results of the contaminant removal performance in aeration tank 1 and aeration tank 2 were not much different, indicating that the treatment in aeration tank 2 was not very effective. In aeration tank 1 the mean COD removal was 73,97±17,65%, PO4-P removal was 53,31±13,72%, total nitrogen removal was 1,57±164,29%, nitrification efficiency was 82,26±16,47%, and denitrification efficiency was -66,4±373,37% in aeration tank 1. Meanwhile, the total energy consumption required for wastewater treatment at WWTP with an average discharge 82.06 l/day is 43.13 kWh/m3 and a cost of Rp. 62,326.00/m3. Phosphate removal required the most energy, at 2.99 kWh/gPO4-P, followed by total nitrogen removal at 1.33 kWh/gTN, ammonia removal at 0.88 kWh/gNH3-N, and COD removal at 0.7 kWh/gCOD


2021 ◽  
Author(s):  
Aline dos Reis Souza ◽  
Mateus Pimentel de Matos ◽  
Luciene Alves Batista Siniscalchi ◽  
Ronaldo Fia

Abstract The objective of this study was to evaluate the effect of the introduction of a complementary aerobic treatment composed of a submerged aerated biological filter (SABF) with a secondary clarifier (SC), followed by horizontal subsurface flow constructed wetlands (CWs), after anaerobic units, on the ability to remove pollutants in different aeration phases (Ph1, Ph2, and Ph3) at the effluent treatment station of the Parque Francisco de Assis (PFA) dog shelter. Ph1 and Ph2 had 7 and 5 hours of daily aeration, respectively, and Ph3 had intermittent aeration every 2 hours. The phases were monitored regarding the removal efficiency of organic matter, solids, nutrients (N, P), coliforms, and detection of Giardia and Cryptosporidium. It was found that post-treatment provided greater removal efficiencies and that the aeration strategy of Ph3 showed mean efficiencies of 71% for COD removal and 77% for BOD removal, being similar or statistically higher, even with less biodegradable effluent, than those of Ph1 and Ph2. The SABF and SC removed N by nitrification and denitrification, leaving a total Kjeldahl nitrogen (TKN) concentration in the effluent of 18 mg L−1. The CW showed potential for simultaneous nitrification and denitrification (SND), in addition to solid filtration. The system did not satisfactorily remove thermotolerant coliforms (ThermC) (1 ± 0 log). PCR suggested the presence of the pathogens Giardia and Cryptosporidium in all post-treatment units in Ph1 and Ph2.


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