The effect of temperature on the nitrification rate in moving bed sequencing batch biofilm systems

Bu çalışmada hareketli yataklı ardışık kesikli biyofilm reaktörlerinde (HYAKBR) sıcaklığın nitrifikasyon hızı ve maksimum ototrofik çoğalma hızı üzerindeki etkilerinin ortaya konulması amaçlanmıştır. Çalışma kapsamında laboratuar ölçekli bir HYAKBR’de evsel nitelikli sentetik atıksu kullanılarak üç farklı sıcaklıkta (20, 15 ve 10°C) nitrifikasyon hızı ve kinetik katsayılar belirlenmiştir. Nitrifikasyon hızı, sıcaklıktan önemli derecede etkilenmiş, 20°C için 0.241 g NOX-N m-2gün-1 ve 10°C için 0.178 g NOX-N m-2gün-1 değerini almıştır. Aynı etki, maksimum ototrofik çoğalma hızı değerleri üzerinde de görülmüş, 20°C için 0.50 gün-1, 15°C için 0.32 gün-1 ve 10°C için 0.09 gün-1 olarak elde edilmiştir.Anahtar Kelimeler: Aktif Çamur; biofilm; hareketli yataklı ardışık kesikli biofilm reaktör; nitrifikasyon.This study investigates the effect of temperature on the nitrification rate and the maximum growth rate of an autotrophic biomass sustained in a moving bed sequencing batch biofilm reactor (MBSBBR). This type of a reactor is a novel hybrid system combining the advantages of attached and suspended activated sludge together with sequencing batch reactors. In this system, biofilm grows on small carrier elements that move along with the water in the reactor by aeration (aeration phase) or by mechanical stirring (anoxic/anaerobic phase). Experimental studies were carried out in a lab-scale MBSBBR, receiving a synthetic influent that had domestic wastewater characteristic, and operated at three different temperatures (20, 15, and 10°C). Evaluation of the results revealed that removal of organic matter at high rates and with efficiencies over 90% was secured at all operation conditions applied. Nitrification rate was significantly influenced by changes in temperature, resulting in a decrease from 0.241 g NOX-N m-2d-1 at 20°C to 0.178 g NOX-N m-2d-1 at 10°C. The same influence was observed on maximum autotrophic growth rate; values of 0.50 d-1, 0.32 d-1, and 0.09 d-1 at 20°C, 15°C, and 10°C were obtained, respectively. In the further studies, heterotrophic and autotrophic kinetic constants should be determined for municipal and different industrial wastewaters.Keywords: Activated sludge; biofilm; moving bed sequencing batch biofilm reactor; nitrification

The effect of temperature and sludge age on COD removal and nitrification in a moving bed sequencing batch reactor

This study investigates the effect of temperature and the sludge age on the performance of a moving bed sequencing batch biofilm reactor (MBSBBR) for COD removal and nitrification. The experiments are conducted in a lab-scale MBSBBR operated at three different temperatures (20, 15 and 10 8C) with a synthetic feed simulating domestic sewage characteristics. Evaluation of the results revealed that removal of organic matter at high rates and with efficiencies over 90% was secured at all operation conditions applied. The nitrification rate was significantly influenced by changes in temperature but complete nitrification occurred at each temperature. The nitrification rates observed at 20 and 15 8C were very close (0.241 mg NOX-N/m2 d, 0.252 mg NOX-N/m2 d, respectively), but at 10 8C, it decreased to 0.178 mg NOX-N/m2 d. On the other hand, the biomass concentration and sludge age increased while the VSS/TSS ratios that can be accepted as an indicator of active biomass fraction decreased with time. It is considered that, increasing biofilm thickness and diffusion limitation affected the treatment efficiency, especially nitrification rate, negatively.TÜBİTAK - YDABCAG-199Y11

Biodegradability of slaughterhouse wastewater with high blood content under anaerobic and aerobic conditions

Abstract: In this work, the biodegradability of wastewater from a slaughterhouse located in Keşan, Turkey, was studied under aerobic and anaerobic conditions. A very high total COD content of 7230mg dm-3 was found, due to an inefficient blood recovery system. Low BOD5/COD ratio, high organic nitrogen and soluble COD contents, were in accordance with a high blood content. A respirometry test for COD fractionation showed a very low readily biodegradable fraction (SS) of 2%, a rapidly hydrolysable fraction (SH) of 51%, a slowly hydrolysable fraction (XS) of 33% and an inert fraction of 6%. Kinetic analysis revealed that hydrolysis rates were much slower than these of domestic sewage. The results underlined the need for an anaerobic stage prior to aerobic treatment. Tests with an anaerobic batch reactor indicated efficient COD degradation, up to around 80% removal. Further anaerobic degradation of the remaining COD was much slower and resulted in the build up of inert COD compounds generated as part of the metabolic activities in the anaerobic reactor. Accordingly, it is suggested that an appropriate combination of anaerobic and aerobic reactors would have to limit anaerobic degradation to around 80% of the tCOD and an effluent concentration above 1000mg dm-3, for the optimum operation of the following aerobic stage

Ozonation application in activated sludge systems for a textile mill effluent

The study investigates the effect of partial ozonation of textile wastewater, both at the inlet (pre-ozonation) and the outlet (post-ozonation) of biological treatment, for the optimization of COD and color removals, both typical polluting parameters associated with the textile industry. Pre-ozonation provides at optimum contact time of 15 minutes 85% color removal, but only 19% COD reduction. Removal of the soluble inert COD fraction remains at 7%, indicating selective preference of ozone for simpler compounds. Post-ozonation is much more effective on the breakdown of refractory organic compounds and on color removal efficiency. Ozonation after biological treatment results in almost complete color removal and a 14% soluble inert COD reduction. The polishing effect of post-ozonation also proves quite attractive from an economical standpoint, involving approximately 50% of the ozone utilization at the same ozone flux rate and contact time, yet providing a lower soluble residual COD level

Wastewater reuse for the minimization of fresh water demand in coastal areas—selected cases from the textile finishing ındustry

Availability of water to the industry often becomes prohibitive, both in terms of quality and cost, in coastal areas. This study takes the textile industry and evaluates the prerequisites of water recovery and reuse. In this context, a large spectrum are studied for their water, the general quality of wastewater generated, quality and treatability of reuse wastewater streams, and expected changes in the overall effluent quality after segregation of the recovery wastewater portion

Effect of ultrasound pretreatment on particle size distribution of wastewater

Bu çalışmanın amacı, bir ön işlem olarak ultrases uygulamasının atıksuların biyolojik arıtılabilirliği üzerine etkisini Partikül Boyut Dağılımı (PBD) değişimini tespit ederek ortaya koymaktır. Bu kapsamda, seçilecek bir atıksu örneğinde herhangi bir işlem uygulanmadan konvansiyonel karakterizasyon ve PBD analizi yapılarak hangi partikül boyutunda, ne kadar KOİ içerdiği belirlenecektir. Daha sonra atıksuya farklı güçlerde ve farklı sürelerde ultrases uygulanarak hazırlanacak herbir atıksu örneğinde yine PBD analizi yapılacaktır. Elde edilen PBD sonuçları karşılaştırılarak değerlendirilecek ve böylece biyolojik arıtılabilirlik açısından optimum ultrases gücü ve uygulama süresi belirlenecektir. Çalışma sonucunda ultrases ile parçalamanın biyolojik arıtılabilirlik açısından etkisi daha iyi anlaşılacak, böylece yüksek enerji gerektiren ultrases prosesi için optimum uygulama şartları, mevcut yöntemlere göre daha hızlı ve güvenilir şekilde tespit edilmiş olacaktır. Bu yöntemle ultrasesin biyolojik arıtılabilirliğin arttırılmasında daha verimli şekilde uygulanması ve aktif çamur havalandırma sistemleri için gerekli havalandırma hacminin ve enerji ihtiyacının azaltılması hedeflenmektedir.Nevşehir Hacı Bektaş Veli Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi NEÜBAP16/F2

Uzun havalandırmalı aktif çamur sistemlerinde arıtma veriminin incelenmesi

Çukurova Üniversitesi Araştırma Fonu (FBE 94.163

Aktif çamurun uzun süreli havalandırılmasında sürenin, aktif çamur ve oksijen kontrasyonunun arıtma verimine etkisi

TEZ527Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1996.Kaynakça (s. 76-80) var.v, 80 s. : rnk.res. ; 30 cm.

Evaluating the effect of ultrasonication on sewage biodegradation by measuring particle size distribution

Application of ultrasonication in optimum conditions as a pretreatment step before activated sludge process could increase the readily biodegradable fraction of wastewaters, but optimization of ultrasonication requires a reliable and simple control parameter. There is a direct relationship between biological degradation rate and particle size of organic substrates and distribution of chemical oxygen demand (COD) in terms of particle size in a wastewater can be determined by particle size distribution (PSD) analysis. The objective of this study is to investigate the applicability of PSD as a tool for monitoring the effect of ultrasonication on the biological treatability of municipal wastewaters. A municipal wastewater sample taken from an activated sludge process influent with high particulate COD (75.4 of 690 mg/L total COD) was subjected to ultrasonic pretreatment with 35 kHz frequency and 0.25 W/mL constant specific power for 2, 4, and 8 min reaction periods. After pretreatment, PSD of each ultrasonicated wastewater sample was determined by sequential filtration-ultrafiltration using eight filters with different pore sizes between 700 and 2 nm. The particulate COD sourced from the organic particles above 700 nm decreased gradually with increased ultrasonication periods from 520 to 326 mg/L (47.2 of total COD), while soluble COD (2 nm particle size) increased from 85 (12.3) to 142 mg/L (20.6). The experimental results demonstrated that PSD analysis can reflect the disintegration of organic particles by ultrasonication and there is a linear relationship between sonication period and COD concentration variations of particle size intervals. Therefore, PSD analysis can be used as a reliable tool for determination of optimal ultrasonication conditions.Nevşehir Hacı Bektaş Veli Üniversitesi - BAP Fonu (NEUBAP16F29

Evaluatioon of the potential and aplicability of renewable energy resources in Nevşehir province

Dünyada gün geçtikçe artan enerji talebi yakın zamana kadar büyük oranda fosil kaynaklardan karşılanmıştır. Ancak gerek bu kaynakların hızla tükenmekte oluşu ve gerekse neden oldukları çevresel zararlar alternatif enerji kaynaklarına yönelmeyi zorunlu hale getirmiştir. Bu bağlamda, yenilenebilir enerji kaynakları son dönemde öne çıkmaktadır. Özellikle gelişmiş ülkelerin termik santralleri azaltarak yenilenebilir kaynaklardan sağladıkları enerjinin oranını hızla arttırdıkları görülmektedir. Türkiye'de de yenilenebilir enerji kullanımı her geçen gün artmakta ve özel ve kamu destekli projeler başlatılmaktadır. Yenilenebilir kaynaklara yapılacak olan yatırımların verimli olabilmesi için öncesinde iyi etüd edilmesi gereklidir. Hangi bölge için hangi yöntemlerin daha uygun olduğu saptanmalıdır. Bu çalışmanın amacı Nevşehir ilindeki yenilenebilir enerji kaynaklarının araştırılarak hangi yöntemin avantajlı ve uygulanabilir olduğunu ortaya koymaktır. Çalışma sonucunda enerji potansiyeli, maliyet ve çevresel etkiler açısından en uygun yöntemin güneş enerji santralleri olduğu belirlenmiştir.The day by day increasing energy demand in the world has been supplied mostly by fossil resources until recently. However, due to both run out and environmental hazards of these resources, it has become an obligation to turn toward alternative resources. In this context, renewable energy resources have been coming forward recently. It can be seen that especially developed countries are increasing their energy supplied from renewable resources while decreasing the number of thermal power plants. Also in Turkey, the renewable energy use is increasing day by day and the projects supported by public or private organizations are initialized. For an efficient renewable energy investment, a good survey is necessary before initialization of a project. It should be determined that which method is more appropriate for which region. The aim of this study is to investigate the renewable energy resources in Nevsehir province to determine that which method has more advantages and is more applicable. As the result of the study, it was determined that the solar power plants are the most suitable method in terms of energy potential, costs and environmental impacts