High BOD Loading Research Articles

고효율 생물반응기에 의한 과일 가공 음료 폐수처리

It is well-known that fruit processing beverage wastewater is one of the severely contaminated industrial wastewaters containing high BOD concentration. This makes it difficult to maintain the proper DO concentration needed in conventional aerobic wastewater treatment process unless the high BOD concentration is properly reduced by pretreatment processes such as anaerobic digestion. In this study, a full-scale high-efficiency bioreactor was applied to cope with the high BOD loading in fruit processing beverage wastewater as a pretreatment of the activated sludge process. The high-efficiency bioreactor, which has multiple draft-tubes for both internal circulation of mixed liquors and aeration, has a merit of requiring small land area for installation. The results of the full-scale high-efficiency bioreactor for fruit processing beverage wastewater treatment were compared with those of anaerobic filter. It was found that the high-efficiency bioreactor was greatly effective in aeration, maintaining a DO level of 2.47 mg/L on average. Substantial removal of pollutants were achieved in the high-efficiency bioreactor, which were 89.9% for BOD, 86.2% for CODMn, 57% for SS,78.9% for T-N, and 80.3% for T-P, while those of an aerobic filter were 45.5% for BOD, 43.1% for CODMn, 50.8% for SS, 55.3% for T-N, and 59.6% for T-P. Thus, it has been demonstrated that the high-efficiency bioreactor had good stability and suitability for the treatment of fruit processing beverage wastewater, as a pretreatment of conventional aerobic wastewater treatment.

Supply Chain of Bioethanol Production from Whey: A Review

Whey, a major byproduct of the cheese and dairy industry, has valuable nutritional constituents but poses a major environmental risk, if disposed off without prior treatment. Whey has a high organic content, its major constituent being lactose (4.5-5% w/v). With a very high BOD and COD load (30,000 – 50,000 ppm and 60.000 – 80,000 ppm respectively) and annual production of over 160 million tonnes, with an estimated growth rate of 1–2% yearly, fermentation of whey to bioethanol has proved to be a lucrative option, both for bioremediation of whey and production of ethanol from waste sources; reducing the costs incurred in otherwise advanced effluent treatment processes required for its disposal. Moreover, with increasing global demand for bioethanol as an alternative to scarce fossil fuels and advocacy by governmental institutions, due to its non-polluting nature aiding in reduced environmental pollution and global warming; conversion of whey to ethanol is progressively more desirable. The aim of this review is to discuss the supply chain involved in the production of ethanol from whey. The study will involve literature survey, experimentation and developing a model.This study looks at the supply chain involved in the production and subsequent distribution of whey, for the purpose of valorization and extraction of valuable constituents, as well as its utilization in production of bioethanol. Based on existing studies, it has been seen that an initial lactose concentration of 200 gL-1 in the whey permeate, provides the maximum yield for ethanol. Under such conditions, maximum ethanol obtained from fermentation of whey was found to be 80.95 kg m-3, proving the economic viability of the process. However, the supply chain of whey for bioethanol production is not well defined, making effectiveness and implementation of ethanol production from whey constricted. Thus, although the environmental risk posed by the vast production of whey, is mitigated by its conversion to ethanol, providing adequate bioremediation of its polluting components, this process is yet to be industrialized widely.

Evaluation of a lab-scale tidal flow constructed wetland performance: Oxygen transfer capacity, organic matter and ammonium removal

Oxygen transfer capacity and removal of ammonium and organic matter were investigated in this study to evaluate the performance of a lab-scale tidal flow constructed wetland. Average oxygen supply under tidal operation (350 g m −2 d −1) was much higher than in conventional constructed wetlands (<100 g m −2 d −1), resulting in enhanced removal of BOD 5 and NH 4 +. Theoretical oxygen demand from BOD 5 removal and nitrification was approximately matched by the measured oxygen supply, which indicated aerobic consumption of BOD 5 and NH 4 + under tidal operation. When BOD 5 removal increased from 148 g m −2 d −1 to 294 g m −2 d −1, neither exhausted oxygen from the aggregate matrix during feeding period (111 g m −2 d −1) nor effluent dissolved oxygen (DO) concentration (2.8 mg/L) changed significantly, demonstrating that the oxygen transfer potential of the treatment system had not been exceeded. However, even though DO had not been exhausted, inhibition of nitrification was observed under high BOD loading. The loss of nitrification was attributed to excessive heterotrophic biofilm growth believed to induce oxygen transfer limitations or oxygen competition in thickened biofilms.

Elimination of Odor and Hydrogen Sulfide Gas by Superoxygenation of the Bluebird Force Main in Laguna Beach, California

Like many cities, the City of Laguna Beach has a transmission main that was sized twenty years ago for a projected level of development that was never realized. Consequently, the transmission main is oversized with daily service velocities running less than optimum. The mountainous terrain of the City requires a complex system of twenty-eight lift stations to serve approximately 18,000 users. The wastewater collection travel time is lengthened due to the lift station trips necessary to reach the transmission pipeline. Travel time is further exacerbated at night when flows are essentially stopped until enough flow is collected to trigger a pumping cycle in some of the smaller residential lift stations. Collectively this typical diurnal cycle is the cause for significant anaerobic conditions to develop in the collection system. The generation of malodorous hydrogen sulfide gas has plagued the City for many years. Over the last ten years, the City has tried many methods and spent a great deal of money to reduce the odor production. Three years ago the City conducted a test to determine the level of hydrogen sulfides released at blow-off vaults. Some of the vaults were located near heavily traveled pedestrian crosswalks in the City. The odorous gas levels were extraordinary and proved that antiquated conventional methods to treat odors were not effective. Costly chemical treatment was discontinued. The City sought new methods for preventative, non-chemical in pipe treatment. The root cause of most odor problems associated with wastewater collection and treatment is the presence of naturally created malodorous gases. The gases are formed by Sulfate Reducing Bacterial, (SRB’s) under anaerobic conditions resulting from the imbalance of high BOD loading and the limited solubility of oxygen into wastewater. This problem is exacerbated in long force mains and slow-cycled residential lift stations due to high microbial oxygen uptake rates, long detention times, and low dissolved oxygen (D.O.) levels. These anaerobic conditions produce significant amounts of hydrogen sulfide (H2S) which is both odorous and highly corrosive. Since anaerobic conditions are precursors to H2S formation, a logical solution to H2S control is to induce aerobic or oxic conditions. SuperOxygenation is a process to sustain aerobic conditions by using an ECO2 “Speece” Cone (Downflow Bubble Contactor) to dissolve pure oxygen into wastewater to prevent the formation of H2S.

Primary facultative ponds in the UK: the effect of operational parameters on performance and algal populations

Waste stabilisation pond systems in the UK are used to treat effluents from small rural communities where there are large fluctuations in both BOD load and inflow; the facultative ponds in these systems have a wide range of hydraulic retention times: between 11-86 days. Low hydraulic retention times in UK ponds are sometimes accompanied by a high BOD loading, although some have a low BOD loading due to high inflows of dilute wastewater. It is not certain whether the performance is affected by the short hydraulic retention time or high BOD loading. A pilot-scale experiment tested the effect of hydraulic retention time (20-60 days) on primary facultative pond performance whilst keeping the BOD loading constant at 80 kg/ha d. It was found that no significant loss of performance was experienced at the test range for BOD and ammonia removal; some loss in SS removal was noted at 20 days' retention time. The effect of BOD loading on the maintenance of algal populations during winter (November(February) was tested at loadings of 50 and 80 kg/ha d. Although there was a significant difference in the concentrations of chlorophyll a and dissolved oxygen between the two loadings, there was no effect on performance.

Environmental pollution and its management in sugar industry in India: An appraisal

The liquid and gaseous effluents produced from sugar industry have adverse impact on ecosystem and environment due to their high BOD load and toxic constituents. In order to reduce pollution hazards, industry is implementing environment management system (EMS) to improve economic and environmental performance of sugar processing unit. A new international EMS standards ISO 14001 is also discussed.

厨芥排水を用いた高負荷条件下の流動床法等の処理性能評価

厨芥排水を用いた高負荷条件下の流動床法等の処理性能評価

Single-stage, single-sludge nitrogen removal by an activated sludge process with cross-flow filtration

Nitrogen removal by a single-stage, single-sludge activated sludge process with cross-flow filtration was qualitatively studied. Artificial wastewater had a BOD/TKN ratio from 1.8 to 24.5. The BOD loading to the process ranged from 0.33 to 1.66 g l −1 d −1, the TKN loading from 0.032 to 0.268 g l −1 d −1 and the sludge retention time (SRT) was quite long (54–4200 d). In each experiment, more than 97% of organic carbon was removed. The sludge biomass concentration (MLVSS) was high at a high volumetric BOD loading. Total Kjeldahl nitrogen (TKN) was successfully nitrified and higher than 29% of the TKN which was loaded to the reactor was removed in many of the experimental runs. The nitrogen balance of each unit was calculated. Denitrification was estimated to be responsible for 39–86% of the removed nitrogen in an aeration vessel. Although denitrification was not observed up to 0.438 g l −1 d −1 of BOD loading, the denitrification rate increased as the BOD loading increased. The percentage of nitrogen removal was a function of the BOD/TKN ratio of the influent. Lower DO concentration did not increase the denitrification rate, but intermittent aeration-BOD loading did increase it; TKN was completely removed up to 0.21 TKN g l −1 d −1, and the denitrification rate reached 0.0074 gN VSS −1 d −1.

Evaluation of Control Strategies for Actinomycete Scum in Full-Scale Treatment Plants

It was found that heavy scum production occurred when cell numbers of actinomycetes were higher than 106 ml−1 in mixed liquor. The reduction of sludge retention time (SRT) was one methodology for controlling actinomycete scum production. This method was successfully applied in the Yokosuka treatment plant when sludge age was maintained at 1.5-2.0 days. The number of actinomycetes cells in mixed liquor decreased to the order of 104 or 105 ml−1. However, in order to reduce SRT, mixed liquor suspended solids (MLSS) had to be low, resulting in a high BOD load. Therefore, it was very difficult to control the scum formation by SRT reduction, while still meeting the water quality standard. The number of actinomycetes in the influent in the Okinawa treatment plant was very high, about 106 ml−1. Since the reduction of SRT was not effective in the Okinawa treatment plant, the anaerobic-oxic process was introduced. Using this process with low SRT, the abnormal foaming and scum production were reduced to 1/2 to 1/3 from the conventional activated sludge process. The number of actinomycete cells in anaerobic-oxic process decreased compared to that of the conventional process.

Wastewater Treatment by a Submerged Contact Media Process Using Net Plates

Wastewater treatment by using a series of bioreactors with submerged net plates, on which microbial growths could be developed, was studied to evaluate its treatment performance and to find suitable operational conditions for sufficient BOD and nitrogen removal. A comprehensive experimental study was carried out by using a bench-scale plant which treated artificial wastewater and a pilot-scale plant which treated municipal wastewater. This process treated well the wastewater with higher pollutant loads in comparison with the conventional activated sludge process. The wastewater containing 200 mg BOD/l was reduced to 20 mg BOD/l at the high BOD loading of 1,94 kg/m3 day and the retention time less than 5 hours. Nitrogen removal could be explained well by an index defined as the product of the water temperature and the retention time. When the ratio, in flow rate, of recycled water to influent was 4 and the index was more than 400, nitrogen removal more than 80 % was obtained.

Evaluation of a Small-Scale Biofilm Process for Wastewater Treatment

Abstract An innovative aerated biofilm process (ABP) was evaluated under laboratory conditions to treat synthetic wastewater. The particular system performed well (&amp;gt;90% BOD removal) at fairly high BOD loading conditions (16.7 g BOD m−2d−1). The process did not require a separate secondary settling chamber to produce an effluent low in suspended solids (&amp;lt;10 mgL−1). The amount of sludge produced was lower than other comparable systems — 0.3g total solids were produced per g of BOD removed at an organic removal rate of 8 g BOD m−2d−1. This process could be adopted for treating wastewater in small systems.

The effect of vinasse on the growth of Helianthus annuus and Pisum sativum: Part I—The effects on some enzymes and chlorophyll and protein content

In this study, the composition of vinasse was first analysed. It was found to contain 8·43% dry matter, 3·3% total ash, 4% crude protein and 0·95% total carbohydrates; BOD load was determined as 63 g litre −1. Subsequently, the effects of vinasse in various concentrations (1, 2·5, 5, 10, 25, 50, 75 and 100%) on the activity of cellulase and pectin methyl esterase and the chlorophyll and protein contents of Pisum sativum and Helianthus annuus were investigated. The activity of these enzymes and the protein and chlorophyll contents in potted plants showed a gradual increase from the control up to 2·5% concentration of vinasse, but decreased at higher concentrations. These different effects of the effluent may be due to the high BOD load and the presence of cell wall cations in it.

Effects of distillery waste on the performance of Cicer arietinum L.

The impact of distillery effluent in various concentrations (1, 2·5, 5, 10, 25, 50, 75 and 100%) on the seed germination, Speed of Germination Index, growth behaviour, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and the seed protein content of Cicer arietinum L. plants was investigated. The percentage and speed of germination of seeds were increasingly retarded with increase in effluent concentration and at 100% concentration there was no germination. The seedlings exhibited maximum shoot length at 5% concentration and maximum root length at 2·5% concentration. The values of root and shoot lengths, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and seed protein content in pot plants exhibited a gradual increase from the control up to 5% concentration and decreases at higher concentrations. The very high BOD load and the presence of excessive concentrations of soluble salts could be responsible for the toxicity of the effluent. The effluent at up to 5% concentration was, however, beneficial for the overall growth parameters studied and can thus be used as a liquid fertilizer.

Improvement of settling characteristics of activated sludge by addition of a floc-forming bacterium

A floc-forming bacterium, strain no. 5, which made very large and easily precipitated flocs, was added as seed sludge in a bench-scale aeration tank. About one week allowed for production of activated sludge which could treat high-BOD wastewater at high-BOD loading while maintaining very good settling characteristics. The strain no. 5 was present at 3% of the activated sludge. Moreover, the settling characteristics of the activated sludge were much improved when the strain no. 5 culture was added to the bench-scale aeration or a large-scale deep aeration tank.

Characteristic evaluation of trickling filter process

Making rational assumptions concerning the biochemical reactions on the microbiological film attached to filter media, a method to predict the fraction of BOD removed of the wastewater is proposed. Effective first-order rate constants, multiplied by the active fraction of the biofilm surface on filter media, are correlated with liquid flow rate, specific surface area of the media, initial BOD in liquid and temperature by analyzing previously reported data Using the correlation obtained, the operating characteristics of both standard and high-rate trickling filters are quantitatively evaluated under various operating conditions and discussed. The application of trickling filter is best limited to rather low BOD loading conditions, because of its low BOD removal rate per unit power consumption at high BOD loading.