Neslihan Manav Demir

Optimization of energy costs in the pretreatment of olive mill wastewaters by electrocoagulation

In this study, the electrocoagulation process was evaluated as a pretreatment process for olive mill wastewaters. Aluminium (Al) and iron (Fe) electrodes, several contact times and 0.5, 1 and 2 A currents were used to compare chemical oxygen demand (COD) removal efficiencies for each case. The optimum contact time and current were 45 minutes and 1 A, respectively, which resulted in a COD removal of 58.7% with an Al electrode. Experimental data from distinct operational conditions were used to fit a model for COD removal efficiencies. Energy consumption was also predicted. Under optimum operational conditions, the treatment cost was approximately €0.13 kg−1 CODremoved and €4.41 m−3. The results showed that the electrocoagulation process was a cost-effective method for the pretreatment of olive mill wastewaters.

Electricity production by a microbial fuel cell fueled by brewery wastewater and the factors in its membrane deterioration

Electricity production from brewery wastewater using dual-chamb er microbial fuel cells (MFCs) with a tin-coated copper mesh in the anode was investigated by changing the hydraulic retention time (HRT). The MFCs were fed with wastewater samples from the inlet (inflow, MFC-1) and outlet (outflow, MFC-2) of an anaerobic digester of a brewery wastewater treatment plant. Both chemical oxygen demand removal and current density were improved by decreasing HRT. The best MFC performance was with an HRT of 0.5 d. The maximum power densities of 8.001 and 1.843 µW/cm2 were obtained from reactors MFC-1 and MFC-2, respectively. Microbial diversity at different conditions was studied using PCR-DGGE profiling of 16S rRNA fragments of the microorganisms from the biofilm on the anode electrode. The MFC reactor had mainly Geobacter, Shewanella, and Clostridium species, and some bacteria were easily washed out at lower HRTs. The fouling characteristics of the MFC Nafion membrane and the resulting degradation of MFC performance were examined. The ion exchange capacity, conductivity, and diffusivity of the membrane decreased significantly after fouling. The morphology of the Nafion membrane and MFC degradation were studied using scanning electron microscopy and attenuated total reflection-Fourier transform infrared spectroscopy.

Treatment of poultry slaughterhouse wastewater using a membrane process, water reuse, and economic analysis

AbstractPoultry slaughterhouse wastewater, which represents one of the most important pollutants in Turkey, is generally treated with conventional biological processes in Turkey and around the world. In this study, poultry slaughterhouse wastewater was treated using laboratory-scale membrane processes, which were substituted for conventional processes. The performances of the membrane processes were investigated in terms of chemical oxygen demand (COD), conductivity, and membrane fluxes. Economic analyses were conducted for several membrane system alternatives. In addition, the alternatives were compared with each other and with conventional economic analysis of the data obtained in this study and data from several previous studies. The membranes used for the membrane processes were AG for reverse osmosis (RO), DK for nanofiltration (NF), and ER for ultrafiltration (UF). The highest COD removal efficiencies were 90% for NF and 97.4% for RO, and the conductivities decreased by 51.7% for NF and 96.6% for RO...

Investigating Biomass Formations at Different Depths in a Slow Sand Filter

A laboratory-scale slow sand filtration (SSF) system was used to investigate biomass formation in different depths of SSF depending on various operating conditions in regard to filtration rate and influent iron-manganese concentrations. Results suggest that biomass formation occurs mainly in the uppermost 1.5 cm of the filter bed with slight contributions from layers between 1.5 cm and 14.5 cm. The highest volatile solids (VS) accumulation was observed in the uppermost layer as 16.93±0.07 mgVS/g dry sand, and the accumulation was found to be a function of both filtration rate and influent iron-manganese concentrations. Hydraulic conductivities were tested as a measure of biomass formation. The highest initial value of hydraulic conductivity was measured as 13.7 μm/s, while the lowest values ranged from 3.28 to 6.62 μm/s at the end of 55 days of operation. Hydraulic conductivities of the upper layers decreased quickly with time, while slight reductions were observed in hydraulic conductivities of the lower layers.

An MS excel add-in for teaching hydraulics of pipe flow in engineering curricula

This paper presents implementation of an MS Excel add‐in incorporating Visual Basic for Applications for teaching pipe flow calculations in undergraduate and graduate level. The add‐in contains a total of 108 functions for several purposes ranging from continuity equation to branching pipes and pipe network problems. Tip texts and a number of userforms were developed for easy use of the tool. A users guide was also prepared that includes the theory of hydraulic calculations and numerical methods involved. Being an add‐in for MS Excel, the tool is a perfect candidate for implementing as an educational tool in undergraduate and graduate level education.

An MS Excel tool for water distribution network design in environmental engineering education

An MS Excel tool for teaching hydraulic analysis of water distribution networks (WDNs) was developed. The tool is able to perform both steady‐state and extended period simulations of a WDN. The tool does not require installation and offers a portable solution to WDN design problem in undergraduate environmental engineering studies.

BİYOLOJİK ATIKSU ARITMA TESİSLERİNDE KARBON VE AZOT GİDERİM VERİMLERİNİN TAHMİNİ AMACIYLA YAPAY SİNİR AĞLARININ KULLANIMI

Biyolojik azot giderimi gerceklestirilen atiksu aritma proseslerinin (AO prosesi) modellenmesi amaciyla Aktif Camur Modeli No. 1 (ASM1) kullanilagelmisse de bu modelde ihtiyac duyulan girdi parametrelerinin tahmin edilmesi cok zaman almaktadir. Bu calisma kapsaminda, ASM1 kadar detayli girdi verisi gerektirmeyen geri beslemeli yapay sinir aglarinin (BPANN) AO proseslerindeki kimyasal oksijen ihtiyaci (KOI), toplam Kjeldahl azotu (TKN) ve toplam azot (TN) giderim verimlerinin tahminindeki performansi test edilmistir. Bu amacla BPANN’de dort farkli aktivasyon fonksiyonu kullanilmistir. Elde edilen sonuclar, AO proseslerindeki KOI, TKN ve TN giderim verimlerinin BPANN ile yuksek dogrulukta tahmin edilebildigini gostermis; en iyi ogrenme ve tahmin yetenegi ise Sinc fonksiyonu ile elde edilmistir. Sinc-BPANN ile elde edilen ortalama kare hatalar KOI giderim verimi icin 2,50 × 10 -4 , TKN giderim verimi icin 4,15 × 10 -4 , TN giderim verimi icin ise 2,65 × 10 -4 olarak hesaplanmistir. Buna gore Sinc-BPANN AO proseslerindeki KOI, TKN ve TN giderim verimlerinin dogrusal olmayan dogasini ASM1’e nazaran cok daha az girdi parametresiyle aciklayabilmektedir.