TREATMENT of TOMATO LYE PEELING WASTEWATER BY FERRIC CHLORIDE COAGULATION and FILTRATION

The suspended solids, soluble and insoluble COD, and particle size were measured for lye peeling wastewater from the tomato industry. the wastewater was treated by conventional coagulation techniques using ferric chloride as a coagulant. Acidification and carbonation were compared as methods to lower the pH. Jar testing was done using a pH level of 9–13 and coagulant levels of 8.6–51 mg/L. the most effective coagulation was achieved at a coagulant dose of 26 mg/L at a pH level of 9 resulting in an average residual turbidity reduction of 92%. Coagulation significantly reduced the insoluble solids (60%), but had no significant effect on dissolved organic matter, thus total COD was only decreased by 14.5%. Filtration had no effect on the suspended or dissolved solids in wastewater.     

Treatment of beverage-processing wastewater in a three-phase fluidised bed biological reactor

This paper presents a study on treatment of beverage‐processing wastewater (BPWW) in a three‐phase fluidised bed bioreactor (TPFBB). Wastewater samples were introduced in the TPFBB and aerated at optimum liquid and gas flow rates while measuring wastewater parameters [pH, chemical oxygen demand (COD), total suspended solids (TSS), total Kjehldahl nitrogen (TKN) and ammonia‐nitrogen (NH₃‐N)]. Two different initial pH levels were studied, i.e. 9.0 and 11.5. The pH of the wastewater was observed to level off at 9.3 after 1 day. The TSS dropped by 95% after 5 days, for both initial pH levels. The NH₃‐N and TKN dropped to similar final concentration independent of initial pH. The COD removal efficiency was observed to depend on the initial pH level. A highest efficiency of 98% and lowest efficiency of 50% were observed at initial pH of 9.0 and 11.5, respectively. The study results show that TPFBB is capable of treating food‐processing wastewater under suitable conditions.     

Evaluation of Lye and Steam Peeling Using Four Processing Tomato Cultivars

Fruit of four eastern tomato cultivars (cvs) were peeled using either high pressure steam or a lye bath under commercial conditions. Percent yield of whole fruit and finished product quality were determined. Yield of 5 sec steam-peeled fruit was 4.1% greater than lye-peeled fruit; no cvs differences were detected. Quantity of blossom-end peel was not affected by peel treatment, but differences among cvs were shown. Steam-peeled tomatoes averaged 6.2 cm² and lye-peeled < 1 cm² total peel/can. There were no differences among treatments or cvs in sensory color scores. Differences in surface bL/a values among cvs at the equator region of fruit were found. Although recovery was greater for steam-peeled than for lye-peeled fruit, canned product quality was better for lye-peeled fruit.     

Desalination of mixed tannery effluent with membrane bioreactor and reverse osmosis treatment

A limiting factor for the reuse and recycling of treated tannery wastewater for irrigation and other uses is the high salt content, which persists even after conventional treatment. Reverse osmosis (RO) membrane treatment has been shown to significantly reduce the salt contents of tannery effluents. However, the high organic content of tannery effluent leads to rapid scaling and biofouling of RO membranes with a consequent reduction in flux rates and performance. Membrane bioreactors (MBR) have been shown to be highly effective in the removal of organic pollutants and suspended solids from tannery effluent. This research investigated the use of a combined MBR and RO treatment process to treat tannery effluents to an acceptable level for irrigation purposes. The MBR was operated at 17-20 h retention time, at a F/M ratio of 0.52 kg COD x kg SS(-1) x day(-1) and a volumetric loading rate of 3.28 kg COD x m(-3) x day(-1). This treatment reduced the COD, BOD, and ammonia concentrations of the effluent by 90-100%. The MBR was shown to be an excellent pretreatment prior to RO technology, due to the high removal efficiency of organic compounds and suspended solids, with average concentrations of 344 mg x L(-1) COD and 20 mg x L(-1) BOD achieved in the permeate. RO treatment reduced the salt content of the MBR permeate by up to 97.1%. The results of the research demonstrated that the MBR system developed was appropriate for the treatment of tannery effluents and, in combination with the RO treatment, reduced the salt content to acceptable levels for irrigation. The MBR pretreatment reduced bio-fouling and scaling of subsequent RO treatment and improved the overall performance of the RO unit. It is believed that this is the first investigation of a combined MBR and RO treatment for tannery effluents. This research provided data for an outline design of a full-scale MBR and RO plant with a treatment capacity of 5000 m3 per day for mixed tannery effluents.     

Oxidation of pharmaceuticals during ozonation of municipal wastewater effluents: a pilot study

To reduce the release of pharmaceuticals and endocrine disruptors into the aquatic environment or to remove them from wastewater intended for direct or indirect reuse, the application of advanced wastewater treatment may be required. In the present study, municipal wastewater effluents were treated with ozone (O3) in a pilot-scale plant consisting of two bubble columns. The investigated effluents, which varied in suspended solids concentrations, comprised an effluent of conventional activated sludge treatment (CAS), the same effluent dosed with 15 mg of TSS L(-1) of activated sludge (CAS + SS), and the effluent of a membrane bioreactor pilot plant (MBR). Selected classes of pharmaceuticals were spiked in the wastewater at realistic levels ranging from 0.5 to 5 microg L(-1). Samples taken at the inlet and the outlet of the pilot plant were analyzed with liquid chromatography (LC)-electrospray tandem mass spectrometry (MS). Macrolide and sulfonamide antibiotics, estrogens, and the acidic pharmaceuticals diclofenac, naproxen, and indomethacin were oxidized by more than 90-99% for O3 doses > or = 2 mg L(-1) in all effluents. X-ray contrast media and a few acidic pharmaceuticals were only partly oxidized, but no significant differences were observed among the three effluents. These results show that many pharmaceuticals present in wastewater can be efficiently oxidized with O3 and that suspended solids have only a minor influence on the oxidation efficiency of nonsorbing micropollutants.     

Demonstration of the Performance of an Inclined Anaerobic Digester in Wine Stillage and Pea Blancher Wastewater Treatment

Disposal of high strength wastes has been a problem in the fruit and vegetable processing industries. We have designed and tested an inclined continuous anaerobic digester for the rapid treatment of unmodified wine stillage (21,000–25,000 mg COD per liter) and waste water from a pea blancher (20,000 mg COD per liter). The digester was successfully operated for periods up to 9 months using feed rates as high as 10.7g COD per liter per day (hydraulic detention time of 2.4 days). COD removal efficiency ranged from 95.9% to 99.5%, and effluent suspended solids were less than 800 mg per liter.     

Effect of Polyelectrolyte Treatments on Waste Strength of Snap and Dry Bean Wastewaters

Processing waters from snap beans (SBW) and dry beans (DBW) were treated with 16 different cationic and anionic polyelectrolytes, singly and in combinations. None of the anionic and only two of the cationic polymers tested worked well for turbidity reduction. Treatments of SBW with Floculite 250 at 10–30 mg/L and of DBW with chitosan at 60–80 mg/L reduced turbidity (NTU) by 81 and 90%, chemical oxygen demand (COD) by 21 and 23%, total solids (TS) by 25 and 8%, suspended solids (SS) by 54 and 44%, dissolved solids (DS) by 22 and 0%, nitrate-nitrogen by 0 and 39%, and total phosphorus by 74 and 18%, respectively. Total aerobic bacteria, coliform bacteria, and mesophilic bacterial spores were reduced by 68 and 20%, 81 and 90%, and 94 and 96% for SBW and DBW treatments, respectively.     

Chemical Optimization of Protein Extraction from Sweet Potato (Ipomoea batatas) Peel

Abstract: Proteins isolated from sweet potatoes (Ipomoea batatas) have been shown to possess antidiabetic, antioxidant, and antiproliferative properties. The objective of this study was to chemically optimize a process for extracting proteins from sweet potato peel. The extraction procedure involved mixing peel with saline solvent to dissolve proteins and then precipitating with CaCl₂. Quadratic and segmented models were used to determine the optimum NaCl concentration and peel to solvent ratio to maximize protein solubility while minimizing solvent usage. A segmented model was also used to optimize the concentration of CaCl₂ used for precipitation. The highest yield was obtained by mixing blanched peelings with 59.7 mL of 0.025 mM NaCl per g peel and then precipitating with 6.8 mM CaCl₂. The results of this study show that potentially valuable proteins can be extracted from peel generated during processing of sweet potatoes and industrial costs can be minimized by using these optimum conditions. Practical Application: Potentially valuable proteins can be extracted from sweet potato peel, a waste product of sweet potato processing.     

Characterization of the Effluent Wastewater from Abattoirs for Land Application

Meat plant wastewater quality depends on water usage, the type of animal slaughtered, and the amount of rendering or processing that is done on site. In Ontario and Quebec, abattoir wastewater total chemical oxygen demand (TCOD) ranged from 2333 to 8627 mg/L, and suspended solids (SS) from 736 to 2099 mg/L, volatile suspended solids (VSS) represented 80% of SS, and protein content varied from 444 to 2775 mg/L. Nitrogen (N) and potassium (P) averaged 6.0 and 2.3 g/100 g of TCOD, respectively. Ammonia and sulfide levels were well below the 3000 and 100 mg/L toxicity level, respectively. The chemical oxygen demand (COD) of fresh blood is high at 375,000 mg/L compared to the COD of liquid manure at 15,000-30,000 mg/L. The concentration of the wastewater can be greatly affected by the efficiency of blood recovery in the blood pit. Abattoir wastewater contains several million colony forming units (cfu) /100 mL of total coliform, fecal coliform, and Streptococcus groups of bacteria. The presence of these nonpathogenic microbes indicates the possible presence of pathogens of enteric origin such as Salmonella ssp. and Campylobacter jejuni and of gastrointestinal parasites such as Ascaris sp., Giardia lamblia, Cryptosporidium parvum, and enteric viruses. Giardia lamblia and Cryptosporidium parvum are not a concern in poultry wastewater. Pathogens might threaten public health by migrating into groundwater or through traveling off-site by surface water, wind, or vectors (i.e., animals, birds) etc. Once the treated abattoir wastewater is applied to land, the potential for spread of any pathogens that might remain in the water or sludge varies with the type of crop and soil to which it is applied.     

生化-混凝法处理制浆中段废水

采用序批式生物膜反应器处理制浆中段废水,研究结果表明,中段废水经序批式生物膜反应器生化处理后,CODCr、BOD5去除率均达到75%以上,AOX去除率也达到55%以上,但色度和TSS的去除效果不理想;GC-MS分析结果表明,生化处理过程中废水中的污染物质由氯代酚为主的氯化有机物转变为较多的酸类物质和烷烃类物质;采用聚合氯化铝对生化出水进行混凝处理可有效降低出水的色度和TSS。废水经生化-混凝处理后,CODCr、BOD5、色度、TSS和AOX去除率均达到90%左右,可达标排放。     

Effect of partial dehydration on quality of canned potatoes

During commercial sterilization, mild to severe breakage of individual potatoes sometimes occurs and the outer layers of potatoes disintegrate into a floury texture referred to as sloughing. Four cultivars of potatoes namely Kufri Badshah, Kufri Bahar, Kufri Chandramukhi and HPS-1/13 were either treated with CaCl₂ or dehydrated before canning to reduce the sloughing. The extent of sloughing in terms of breakage observed visually depended on the cultivar of potatoes. Although CaCl₂ treatment reduces sloughing, it causes turbidity of the brine. Partial dehydration of potatoes before canning was helpful in reducing sloughing and it allowed a higher filling of potato solids in the can thereby increasing drained weight. HPS-1/13 cultivar was found most suitable for dehydrocanning.     

聚酰胺-胺树形分子在造纸废水处理中的应用研究

使用聚酰胺-胺(PAMAM)树形分子对造纸厂产生的废水进行絮凝处理,研究了树形分子的代数、溶液的酸度以及树形分子的加药量对SS和COD去除率的影响。研究表明,PAMAM树形分子对造纸废水具有优异的絮凝效果,在pH值3.0左右,PAMAM在50mg/L的条件下SS和CODCr去除率可分别达到91%和89.4%。     

悬浮填料生物膜-MBR系统处理制浆中段废水的研究

采用悬浮填料生物膜-MBR系统处理制浆中段废水,并与好氧活性污泥系统进行了对比。驯化过程中,尤其是制浆中段废水所占比例较高时,悬浮填料生物膜-MBR的处理效果和污泥理化特性均明显优于好氧活性污泥系统。驯化结束时悬浮填料生物膜-MBR系统COD_(Cr)去除率高达90.6%,悬浮液固形物浓度(MLSS)达到3876 mg/L,污泥体积指数(SVI)为60.3 m L/g,而好氧活性污泥系统COD_(Cr)去除率为82.4%,MLSS为3135 mg/L,SVI为70.3 m L/g。对出水的紫外扫描结果表明,悬浮填料生物膜-MBR系统对200~300 nm波长处特征污染物的降解效果明显优于好氧活性污泥系统。     

生物强化法处理杏仁脱苦废水的试验研究

杏仁脱苦废水是一种含氰化物的有机废水。利用从杏仁废水中分离出的两株菌,结合厌氧—好氧组合工艺,对杏仁废水中生物强化法的处理效果进行研究。实验数据表明,C菌株对有机物的去除效果明显：在进水COD（化学需氧量）为2000mg/L-4000mg/L,采用厌氧24h—好氧72h组合工艺,去除率达到90%以上,出水中COD为92.35mg/L,达到GB8978-1996一级标准。     

Characterization and Bioconversion of Great Northern Bean Blancher Effluent

Chemical characterization of blanching effluent and bioconversion by Hansenula anamola was performed. The effluent contained 27,000 mg/L BOD and 31,000 mg/L total solids including 49.5% starch and 23.6% protein (dry basis). A high biochemical oxygen demand (BOD): chemical oxygen demand (COD) ratio (0.95) indicated a waste easily and completely degradable, with nitrogen and phosphorus levels above those necessary for unimpeded microbial growth. Batch fermentations of raw effluent produced 12g dry cells/L, containing 53% protein, with a corresponding 84% reduction in BOD. Great Northern bean blanching effluent was demonstrated to be a suitable growth medium for H. anomala.     

Reduction of acrylamide formation by selected agents in fried potato crisps on industrial scale

Great interest and rapid research efforts on acrylamide in foods followed an announcement in April 2002 by the Swedish National Food Authority and the University of Stockholm. Reduction of acrylamide in high-temperature processing foods, including selection of the raw material and variation of processing parameters, etc. were extensive reported. In this research, effect of some agents on acrylamide formation was investigated. A glucose-asparagines reaction model system was used to test the effect of ferulic acid, catechin, CaCl₂, NaHSO₃, and l-cysteine on inhibition of acrylamide formation and three efficient inhibitors, NaHSO₃, CaCl₂ and l-cysteine were screened. The results showed that immersing of the fresh potato chips using different concentration of the agents greatly inhibited acrylamide formation in fried potato crisps, and the efficiency increased as their concentrations increased; among them, l-cysteine is the most efficient agent but CaCl₂ is most potential. Effects of these food additives on the texture of fried potato crisps were also studied. It was found that l-cysteine showed little effect on the texture of the crisps and CaCl₂ is regarded as the suitable choice because of its low price and the acceptable mouth feel of fried crisps treated by CaCl₂, although it increased the brittleness. Moreover, the application of CaCl₂ in industrial production of fried potato crisps was also studied. In the blanching process (deactivation process of enzymes at 85 °C), a computerized electrical conductivity detector was used to keep the concentration of CaCl₂ at constant and the result showed that immersion of potato slices in CaCl₂ solution at 5 g/L reduced acrylamide formation by more than 85% in fried crisps.Industrial relevanceThis research presents a technology to inhibit acrylamide formation in fried potato chips by immersion of fresh potato chips with some food additives. The approach suggested that cysteine and calcium chloride significantly decreased the content of acrylamide in fried potato chips and their concentrations could be kept constant by using a conductor as a detector.     

柑橘罐头加工工序排放水水质的分析研究

柑橘罐头加工排放水是果蔬加工中较难治理的一种废水。本文针对柑橘罐头加工废水富含有机质的特性,首次将柑橘罐头生产排放水分段收集和分析,进行水质感官理化指标和微生物指标测定,研究表明:柑橘罐头不同加工工序的水质差异很大,按其综合水质可分为轻度,中度和重度污染水。第三次漂洗水、分级机水、挑选输送水和杀菌冷却水为轻度污染水,含少量肉眼可见悬浮物,COD在31.30~110.35 mg/L之间;碱处理后的第一次和第二次漂洗水为中度污染水,含较多肉眼可见悬浮物,COD在500.40~1515.40mg/L之间;酸处理水和碱处理水为重度污染水,含大量肉眼可见悬浮物,COD在6827.80~13207.10 mg/L之间。第三次漂洗水、分级机水、挑选输送水和杀菌冷却水水耗量占整个工艺65%以上,污染程度较轻,可进一步进行回用水源研究。     

Enhanced treatment efficiency of an anaerobic sequencing batch reactor (ASBR) for cassava stillage with high solids content

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m³ d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.     

发酵甘油废水的处理工艺

针对发酵甘油生产过程中的淀粉质原料浸泡废水固体悬浮物质量浓度高和提取废水难以生物降解的特性,分别采用沉淀法和Fenton试剂法对其进行预处理,再与发酵废水混合后,采用UASB-SBR组合工艺进行处理.结果表明:当进水COD为6 800-7 360 mg／L时,处理后出水COD可降到100 mg／L以下,出水NH3-N降到15 mg／L以下,系统出水可以达标排放.     

A novel strategy of acrylamide mitigation in fried potatoes using asparaginase and high pressure technology

The potentiality of high pressure processing (HPP) to possibly enhance diffusion of asparaginase into raw potato sticks, and consequently on reduction of acrylamide levels in fried potatoes was evaluated. Raw potato sticks were immersed in asparaginase (10,000 ASNU/L) and immediately subjected to 0.1, 100, 200 and 400 MPa for 5 min, with total enzymatic reaction times of 5, 10 and 20 min and room temperature. Pressurized raw potato sticks became softer, more flexible, and required lower energy for cutting (up to 47% less); the roughness of potato surface and moisture content were slightly reduced; and the concentration of soluble solids in the exterior solutions increased, indicative of a leaching effect. Due to changes induced by asparaginase and/or HPP on raw potatoes, fried potatoes exhibited higher weight loss after frying, and higher hardness (crispness). The combined treatment with asparaginase and HPP showed to reduce acrylamide levels by 26–47%, while with asparaginase or HPP alone there was no significant reduction.Industrial relevanceHPP is a non-thermal technology that may be used as a pre-treatment for the production of fried potatoes with different/better textural and nutritional properties, as well as to reduce energetic costs of some industrial steps of the production of fried potatoes (for instance, the cutting process and frying time). Also, a combined pre-treatment with HPP and asparaginase may be used as a strategy of acrylamide mitigation in fried potatoes.