Olive oil history,production and by-product management

In this review paper, the history of the olive tree and the development of the main olive oil extraction systems employed in the past are presented. Furthermore, the management techniques employed from antiquity until today for the treatment of olive mill wastewater (OMW), which constitutes the most important by-product of olive oil production, are addressed and compared. Reference is also made to global olive oil production, the environmental impacts of the uncontrolled disposal of OMW, and to the legal framework concerning its management in the main olive oil producing countries. Other by-products of olive processing are also discussed.     

Performance of an ecological treatment system at three strengths of dairy wastewater loading

Ecological treatment systems, which rely on renewable resources, have successfully treated municipal and industrial effluents with reduced costs compared to conventional methods, but their capacity to treat dairy wastewater is unknown. In order for ecological treatment systems to be practical for agriculture they must be able to treat a significant portion of a dairy's daily wastewater production. In this study, the impact of three strengths of dairy wastewater on effluent water quality was assessed. Three ratios of wastewater and city water—(1) one part wastewater:three parts city water, (2) one part wastewater:one part city water, and (3) two parts wastewater:one part city water—were each pumped into an ecological treatment system. Influent and effluent water samples were analyzed for PO₄-P, TP, TN, NH₄-N, NO₃-N, total suspended solids (TSS), and carbonaceous biochemical oxygen demand (CBOD₅). Influent dairy wastewater volumetric loading rates were much greater than those of municipal wastewater. Regardless of influent wastewater strength, concentrations of all measured variables were significantly reduced between the influent and effluent of the ecological treatment system. At the lowest wastewater strength, PO₄-P was reduced 39%, TN 83%, and NH₄-N 89%, while at the highest wastewater strength, PO₄-P was reduced 41%, TN 79%, and NH₄-N 70%. Increased wastewater strength required greater aerobic treatment volume to reduce concentrations of NH₄-N and CBOD₅.     

Simultaneous nitrification, denitrification, and phosphorus removal from nutrient-rich industrial wastewater using granular sludge

The biological removal of nitrogen and phosphorus from nutrient-rich abattoir wastewater using granular sludge has been investigated. A lab-scale sequencing batch reactor, seeded with granular sludge developed using synthetic wastewater, was operated for 13 months under alternating anaerobic and aerobic conditions. It is demonstrated that the granules could be sustained and indeed further developed with the use of abattoir wastewater. The organic, nitrogen, and phosphorus loading rates applied were 2.7 gCOD L(-1) day(-1), 0.43 gN L(-1) day(-1), and 0.06 gP L(-1) day(-1), respectively. The removal efficiency of soluble COD, soluble nitrogen and soluble phosphorus were 85%, 93%, and 89%, respectively. However, the high suspended solids in the effluent limited the overall removal efficiency to 68%, 86%, and 74% for total COD, TN, and TP, respectively. This good nutrient removal was achieved through the process known as simultaneous nitrification, denitrification, and phosphorus removal, likely facilitated by the presence of large anoxic zones in the center of the granules. The removal of nitrogen was likely via nitrite optimizing the use of the limited COD available in the wastewater. Accumulibacter spp. were found to be responsible for most of the denitrification, further reducing the COD requirement for nitrogen and phosphorus removal. Mineral precipitation was evaluated and was not found to significantly contribute to the overall nutrient removal. It is also shown that the minimum HRT in a granular sludge system is not governed by the sludge settleability, as is the case with floccular sludge systems, but likely by the limitations associated with the transfer of substrates in granules.     

Analysis of ammonia loss mechanisms in microbial fuel cells treating animal wastewater

Ammonia losses during swine wastewater treatment were examined using single- and two-chambered microbial fuel cells (MFCs). Ammonia removal was 60% over 5 days for a single-chamber MFC with the cathode exposed to air (air-cathode), versus 69% over 13 days from the anode chamber in a two-chamber MFC with a ferricyanide catholyte. In both types of systems, ammonia losses were accelerated with electricity generation. For the air-cathode system, our results suggest that nitrogen losses during electricity generation were increased due to ammonia volatilization with conversion of ammonium ion to the more volatile ammonia species as a result of an elevated pH near the cathode (where protons are consumed). This loss mechanism was supported by abiotic tests (applied voltage of 1.1 V). In a two-chamber MFC, nitrogen losses were primarily due to ammonium ion diffusion through the membrane connecting the anode and cathode chambers. This loss was higher with electricity generation as the rate of ammonium transport was increased by charge transfer across the membrane. Ammonia was not found to be used as a substrate for electricity generation, as intermittent ammonia injections did not produce power. The ammonia-oxidizing bacterium Nitrosomonas europaea was found on the cathode electrode of the single-chamber system, supporting evidence of biological nitrification, but anaerobic ammonia-oxidizing bacteria were not detected by molecular analyses. It is concluded that ammonia losses from the anode chamber were driven primarily by physical-chemical factors that are increased with electricity generation, although some losses may occur through biological nitrification and denitrification.     

Pretreatment of textile dyeing wastewater using an anoxic baffled reactor

A study on pretreatment of textile dyeing wastewater was carried out using an anoxic baffled reactor (ABR) at wastewater temperatures of 5-31.1 degrees C. When hydraulic retention time (HRT) was 8h, the color of outflow of ABR was only 40 times at 5 degrees C and it could satisfy the professional discharge standard (grade-1) of textile and dyeing industry of China (GB4287-92). The total COD removal efficiency of ABR was 34.6%, 47.5%, 50.0%, 53.3%, 54.7% and 58.1% at 5, 9.7, 14.9, 19.7, 23.5 and 31.1 degrees C, respectively. Besides, after the wastewater being pre-treated by ABR when HRT was 6h and 8h, the BOD5/COD value rose from 0.30 of inflow to 0.46 of outflow and from 0.30 of inflow to 0.40 of outflow, respectively. Experimental results indicated that ABR was a very feasible process to decolorize and pre-treat the textile dyeing wastewater at ambient temperature. Moreover, a kinetic simulation of organic matter degradation in ABR at six different wastewater temperatures was carried through. The kinetic analysis showed the organic matter degradation was a first-order reaction. The reaction activation energy was 19.593 kJ mol(-1) and the temperature coefficient at 5-31.1 degrees C was 1.028.     

Design and analysis of a solar reactor for anaerobic wastewater treatment

The aim of this research was to design a solar heated reactor system to enhance the anaerobic treatment of wastewater or biological sludge at temperatures higher than the ambient air temperature. For the proposed reactor system, the solar energy absorbed by flat plate collectors was transferred to a heat storage tank, which continuously supplied an anaerobic-filter reactor with water at a maximum temperature of 35 degrees C. The packed reactor was a metallic cylindrical tank with a peripheral twin-wall enclosure. Inside this enclosure was circulated warm water from the heat storage tank. Furthermore, a mathematical model was developed for the prediction of the temperature distribution within the reactor under steady state conditions. Preliminary results based on model simulations performed with meteorological data from various geographical regions of the world suggested that the proposed solar reactor system could be a promising and environmentally friendly approach for anaerobic treatment of wastewater and biological sludge.     

Feasibility of using constructed wetland treatment for molasses wastewater treatment

The surface flow constructed wetland (SFCW) with Cyperus involucratus, Typha augustifolia and Thalia dealbata J. Fraser was applied to treat anaerobic treated-molasses wastewater (An-MWW) under the organic loading rates (OLRs) of 612, 696, 806, 929 and 1,213 kg BOD(5)ha(-1)day(-1). The results showed that both removal efficiency and plant growth rate were increased with the decrease of organic loading rate (OLR). All tested-plant species could not grow under OLR of higher than 696 kg BOD(5)mg l(-1) (p>0.05). Also, the plant-biomass of the systems was reduced by 10.4%, 26.5%, and 64.7% of initial plant-biomass under the OLR of 806, 929 and 1,213 kg BOD(5)ha(-1)day(-1), respectively. However, all tested-plant species showed the same pattern on the plant-biomass production yield and removal efficiency. The highest SS, BOD, COD, total phosphorus, NH(4)(+), NO(3)(-) and molasses pigments (MP) removal efficiencies of 90-93%, 88-89%, 67%, 70-76%, 77-82%, 94-95% and 72-77%, respectively were detected under the OLR of 612 kg BOD(5)ha(-1)day.     

糖蜜酒精废液厌氧生物降解性能的BMP分析

在中温条件下,对pH值和营养比例两个影响因素进行了糖蜜酒精废液的BMP分析,探讨酒精废液在厌氧消化过程中产甲烷量、COD浓度的变化情况,以及COD去除率与产气量、pH值之间的关系。研究结果表明,厌氧处理法能够使糖蜜酒精废液的有机负荷大大降低,CODcr去除率最高可达90．6％;在调节营养比例的条件下,pH=8．5时甲烷菌活性最佳,其中COD．P=300：1的产甲烷量最高。     

Enhanced COD and nitrogen removals for the treatment of swine wastewater by combining submerged membrane bioreactor (MBR) and anaerobic upflow bed filter (AUBF) reactor

In order to enhance performances of organics removal and nitrification for the treatment of swine wastewater containing high concentration of organic solids and nitrogen than conventional biological nitrogen removal process, a submerged membrane bioreactor (MBR) was followed by an anaerobic upflow bed filter (AUBF) reactor in this research (AUBF–MBR process). The AUBF reactor is a hybrid reactor, which is the combination of an anoxic filter for denitrification and upflow anaerobic sludge blanket (UASB) for acid fermentation. In the AUBF–MBR process, it showed a considerable enhancement of the effluent quality in terms of COD removal and nitrification. The submerged MBR could maintain more than 14,000 mg VSS/L of the biomass concentration. Total nitrogen (T-N) removal efficiency represented 60% when internal recycle ratio was three times of flow-rate (Q), although the nitrification occurred completely. Although the volatile fatty acids produced in AUBF reactor can enhance denitrification rate, but the AUBF–MBR process showed reduction of overall removal efficiency of the nitrogen due to the reduction of carbon source by methane production in the AUBF reactor compared to that of theoretical nitrogen removal efficiency.

Long-term operation of the submerged MBR showed that the throughputs of the submerged MBR were respectively 74, 63, and 31 days at 10, 15, and 30 L/m² h (LMH) of permeate flux. Resistance to filtration by rejected solid is the primary cause of fouling, however the priority of cake resistance (R_c) and fouling resistance (R_f) with respect to filtration phenomenon was different according to the amount of permeate flux. The submerged MBR, here, achieved a steady-state flux of 15 LMH at 0.4 atm. of trans-membrane pressure (TMP) but the flux can be enhanced in the future because shear force by tangential flow will be greater when multi-layer sheets of membrane were used.     

焦化废水处理厂接触氧化池中降酚菌群的苯酚羟化酶大亚基基因多样性

研究了某焦化废水处理厂接触氧化池中降酚菌群的苯酚羟化酶大亚基基因(thelargestsubunitofthemulti-componentphenolhydroxylase,LmPH)的多样性。通过温度梯度凝胶电泳(temperaturegradientgelelectrophoresis,TGGE)对比分析了氧化池4个区段(O1—O4)中降酚菌群LmPH的组成。它们的TGGE图谱完全一样,相似性为100%,表明该处理池中不同区段的降酚菌群的功能基因组成是高度相似的。以O4段的菌群为代表建立LmPH基因克隆文库,从中挑选了49个克隆测序。依据LmPH基因的DNA序列所推测的氨基酸序列完全相同的归为一类的原则,49个克隆被分为16种类型,其中优势LmPH基因主要有5种类型(多于4个克隆),而另外11种类型都只有1个克隆。与已知基因同源性超过90%的有7种类型,低于80%的有2种类型。基于氨基酸序列的系统进化树分析表明,LmPH文库中绝大部分的类型都属于低亲和常数(low-Ks)的LmPH,占所有克隆的92%。只有一个类型属于高亲和常数(high-Ks)的。因此,处理焦化废水的工业装置中不仅具有丰富多样的苯酚羟化酶基因类型,而且以编码低亲和常数的占优势地位,而过去报道的通过富集培养分离得到的降酚菌则多带有高亲和常数的酶。这提示我们传统的富集培养方法并不能筛选到生态环境中的真正优势功能菌。