Three-body monopole corrections to the realistic interactions

It is shown that a very simple three-body monopole term can solve practically all the spectroscopic problems--in the $p$, $sd$ and $pf$ shells--that were hitherto assumed to need drastic revisions of the realistic potentials.Comment: 4 pages, 5figure

Influence of Biosurfactant on aerobic biodegradation of polyaromatic hydrocarbons

Biyolojik olarak parçalanması oldukça güç olan poliaromatik hidrokarbon (PAH) gibi toksik ve kirletici maddeler birçok endüstri kuruluşlarının atıksuları ile doğaya bırakılmaktadır. Petrokimya endüstrisi bu endüstri kuruluşları içerisinde büyük ve önemli bir yere sahiptir. PAH'lar ham petrolün işlenmesi sırasında ortaya çıkan, toksik, mutajenik ve karsinojenik bileşiklerdir. Bu çalışma, EPA tarafından petrokimya endüstrilerinde öncelikli olarak belirtilen 15 adet PAH üzerine odaklanmıştır. Laboratuvar koşullarında Sürekli Tam Karışımlı Aerobik Tank Reaktör'de (SKTR) beslemesi için atıksu İzmir'deki bir petrokimya endüstrisi atıksu arıtma tesisinin havalandırma ünitesi girişinden alınmıştır. 20 günlük çamur yaşında ve 5 günlük hidrolik bekleme sürelerinde toplam 15 PAH'ın sistem içerisinde giderim verimleri incelenmiştir. Kontrol reaktöründe (biyosürfaktansız) 15 adet PAH içerisinden üç benzen halkalılar %35–60 arıtma verimi ile giderilirken yüksek benzen halkalı PAH'ların giderimi %25–50 olarak gerçekleşmiştir. Yüksek benzen halkalı PAH'lar biyolojik olarak çok düşük verimlerle giderilen PAH'ların sürekli karıştırmalı aerobik tank reaktör sisteminde rhamnolipid biyosürfaktanı (15–30–50–150 mg/L) aerobik biyolojik giderim verimine etkileri değerlendirilmiştir. Optimum biyosürfaktan dozu 15 mg/L olarak belirlenmiştir. Bu dozda 15 mg/L rhamnolipid içeren Sürekli Karışımlı Tank Reaktörde (SKTR)'de petrokimya endüstrisi atıksularının aerobik arıtılabilirliği ile yapılan çalışmada 30 günlük işletme süresi sonunda maksimum KOİ giderme verimi %78 olmuştur. Kalıcı, zor ayrışabilen PAH'lardan 2 ve 3 benzen halkalı yapılar; %68–94, moleküler ağırlıkları daha büyük olan 4, 5 ve 6 benzen halkalı yapılar %50–74 artma verimi ile giderilmiştir. Anahtar Kelimeler: Aerobik, aktif çamur sistemi, biyosürfaktan, petrokimya, poliaromatik hidrokarbonlar (PAH).Some toxic pollutants such as PAHs which are persistent are releasing to the environment with industrial wastewater flows. These organics are degraded with difficulty and accumulated in the environmental ecosystem. They are toxic and carcinogenic to the humans and to the viable microorganisms resulting in significant irreversible hazardous effects. Petrochemical industry wastewaters are the most important source of the persistent PAHs which are toxic, mutagenic and carcinogenic substances. PAHs are producing during petroleum production. In this study, the aerobic treatability of 15 PAHs was studied since they are named as priority pollutants by EPA. In the laboratory studies, an aerobic stirred reactor was used for the biodegradation of PAHs in the wastewater taken from the influent of aerobic activated tank of the petrochemical industry wastewater treatment plant in Izmir. The removal efficiencies of acenaphthene (ACT), fluorene (FLN), phenanthrene (PHE), anthracene (ANT), carbazole (CRB), fluoranthene (FL), pyrene (PY), benz[a]anthracene (BaA), chrysene (CHR), benz[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (IcdP), dibenz[a,h]anthracene (DahA), benzo[g,h,i]perylene (BghiP) were determined in wastewater. The removal efficiencies of 15 PAHs was investigated in the surfactant added aerobic completely stirred tank reactor and in the control reactor without biosurfactant at a sludge retention time of 20 days and at a hydraulic retention time of 5 days in the reactor systems. The COD removal efficiencies in control, in 15 mg/L, 30 mg/L, 50 mg/L and 150 mg/L rhamnolipid containing reactors were 70-77%, 74-79%, 70-78%, 66-72% and 56-65%. The PAHs with 3 benzene rings was degraded with a removal efficiency of 35-60% while the PAHs with 5 benzene ring were removed with a removal efficiency of 25-50% in control reactor. It was observed that the degradation of PAHs with high molecular weights are very difficult. The effect of increasing biosurfactant (15-30-50-150 mg/L) concentrations on the removal of PAHs was investigated in PAHs with high and low benzene rings. For maximum PAH removal the optimum biosurfactant dose was 15 mg/L. In this dose, the PAHs with 3 benzene ring was removed with a removal efficiency of 68-94%, while the PAHs with 4-5 benzene ring was removed between 50% and 70% under biologic degradation conditions. In 15 mg/L rhamnolipid containing reactor the dissolved COD removal efficiency is high compared to the control reactor. It was found that the increasing of rhamnolipid concentrations did not affect positively the soluble COD removal efficiency while to the highest soluble COD removal efficiency was reached at a rhamnolipid concentration of 15 mg/L. Low dissolved COD removal efficiencies in reactors containing 50 and 150 mg/L rhamnolipid administered reactors compared to control could be attributed to the presence of a possible toxicity for the aforementioned rhamnolipid doses. Since the maximum dissolved COD removal efficiencies was obtained at a rhamnolipid dose of 15 mg/L, this level of a surfactant was obtained as the optimum rhamnolipid dose for a raw Petrochemical Industry wastewaters. The main dissolved COD removal way with simultaneous rhamnolipid uptake pathway and degradation of PAHs could be explained as follows: Since 15 mg/L rhamnolipid is readily biodegradable could be uptaken by the microorganisms to the cells and could be used as feed together with dissolved COD. In the declaration of Ministry of Environment and Forestry on dated 26/11/2005 and numbered 26005 in the Official news paper it was mentioned that "the hydrocarbons namely ANT ve BaP, BbF, BghiP, BkF, FLN, In123cdP ve NaP" are listed in the Regulation Water Pollution Control for Hazardous Compouds (76/464/AB) attachment while there is no a limitation to the receiving water discharge Standard for the aforementioned PAHs. The PAHs namely BaA, CHR, BbF, BkF, BaP, DahA, BghiP and In123cdP have potential cancer risks. The aforementioned PAHs were removed with treatment efficiencies of 65%, 73%, 65%, 63%, 67%, 70%, 60% and 50% in the aerobic completely stirred tank reactor containing 15 mg/L rhamnolipid dose. For this reason it should be added some discharge limitation to the Water and Wastewater Pollution Regulation for PAHs in the petrochemical, dye and chemical industries. Furthermore, the PAH concentrations in the effluent of the aerobic reactors should be assessed with toxicity tests. Keywords: Aerobic activated sludge system, biosurfactant, petrochemical, polyaromatic hydrocarbons (PAHs)