Five-day Biological Oxygen Demand Research Articles

Impact of urbanization and industrialization upon surface water quality: A pilot study of Panzhihua mining town

In order to investigate the impact of urbanization and industrialization on surface water quality, a pilot study of Panzhihua (攀枝花) mining town was carried out. The urbanization of Panzhi- hua region was dominated by industry development and population growth. The level of urbanization showed that it was 18.44% in 1965, and reached 45.99% in 1983. Then, it reached 53.71% in 2005, so the urbanization process was very rapid in Panzhihua region. In the process of industrialization, the level of industrialization was fluctuated at around 70% from 1965 to 2005, which was influenced by mining, extracting, and smelting production. In the processes of urbanization, population growth caused an increase in life pollution sources, and an amount of effluents bearing coliform, COD (chemi- cal oxygen demand), NH4 + -N, and BOD5 (five-day biological oxygen demand) were released into Jinsha (金沙) River, which could cause decline in the surface water quality. While in the processes of industri- alization (especially industrial scale expansion), more effluent bearing heavy metals could cause degra- dation of surface water quality. Thus, the measures, such as adjusting industry structure, optimizing the cleaning technology, and controlling pollution sources, should be enhanced to alleviate the current state of water quality exacerbation.

Water Quality and Nutrient Aspects in Recirculating Aquaponic Production of the Freshwater Prawn, Macrobrachium rosenbergii and the Lettuce, Lactuca sativa

The purpose of this study was to investigate the effects of different nutrients and their ability to improve the production of Macrobrachium rosenbergii and Lactuca sativa in a prototype recirculating aquaponic (RA) system. Experimental units were set up with different amounts of supplemented organic and inorganic (complex minerals) nutrients to carry out the study. The results indicated that desirable growth of M. rosenbergii might be possible in RA systems when supplied sufficient levels of macro-micro nutrients. Analyses of nutrients in the prawn culture tanks demonstrated that ammonia and nitrate concentrations were critical in maintaining proper water quality during the culture period. Five-day biological oxygen demand (BOD5) increased significantly with the increased loading of organic supplement in the rearing tanks. A significant linear relationship of chlorophyll a and N:P ratio was observed among the treatments. The combination of complex minerals and organic chicken manure (CM15) displayed a higher N:P ratio, maximal total yield and did not show adverse effects of NH3 concentrations and other important water quality parameters.

Surface Run-Off Water Quality from Agricultural Lands and Residential Areas

This study was conducted to characterize surface run-off water quality from sugar cane fields, pasturelands and residential areas, and to assess the effectiveness of best management practices (BMPs) in controlling non-point source pollution. From October 2002 to September 2005, the five-day biological oxygen demand (BOD5), total suspended solids (TSS), nitrate/nitrite-N (NO3/NO2-N), soluble reactive phosphate (SRP), total phosphorus (TP), total nitrogen (TN) and pH were determined in surface run-off water from two sugar cane fields, two pasturelands and two residential areas in south-western Louisiana. Faecal coliform counts were carried out on run-off samples from the two pasturelands. The BMPs implemented in one of the sugar cane fields included drop-pipe structures, nutrient management, reduced tillage and the application of herbicides to eliminate summer cultivations, while those implemented in one of the pasturelands included drop-pipe structures, cross-fencing, water points, nutrient management, improved forage planting and managed rotational grazing. Average TSS concentration in surface run-off from the sugar cane fields was significantly higher than the average TSS concentration in the surface run-off from the pastureland and residential areas. Average BOD5 concentrations in surface run-off from the sugar cane fields and pasturelands were significantly higher than the average BOD5 concentration in surface run-off from the residential site. Average TN and NO3/NO2-N concentrations in surface run-off from the sugar cane fields were significantly higher than the average concentration for the pasturelands and residential areas surface run-off. Average TP and SRP concentrations in surface run-off from the pasturelands were significantly higher than the average TP and SRP concentrations in surface run-off from the sugar cane fields and residential areas. The BOD5 was significantly positively correlated with TSS, TN, TP, SRP and NO3/NO2-N. Surface run-off from the sugar cane field with BMPs showed relatively lower median values of TN, TP, NO3/NO2-N and SRP and a slightly higher BOD5 value than the surface run-off from the sugar cane field without BMPs. Similarly, the surface run-off from pastureland with BMPs showed lower median values for TSS, TN and NO3/NO2-N than the surface run-off from pastureland without BMPs.

Microwave enhanced chemical reduction process for nitrite-containing wastewater treatment using sulfaminic acid

High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process. In this study, a novel microwave-enhanced chemical reduction process (MECRP) using sulfaminic acid (SA) was proposed as a new manner to treat such type of wastewater. Based on lab-scale experiments, it was shown that 75%–80% nitrite (NO 2 −) could be removed within time as short as 4 min under 50 W microwave irradiation in pH range 5–10 when molar ratio of SA to nitrite (SA/NO 2 −) was 0.8. Pilot-scale investigations demonstrated that MECRP was able to achieve nitrite and chemical oxygen demand (COD) removal with efficiency up to 80% and 20%, respectively under operating conditions of SA concentration 80 kg/m 3, SA/NO 2 − ratio 0.8, microwave power 3.4 kW, and stirring time 3 min. Five-day biological oxygen demand (BOD 5)/COD value of treated effluent after MECRP was increased from 0.05 to 0.36 (by 620%), which clearly suggested a considerable improvement of biodegradability for subsequent biological treatment. This study provided a demonstration of using microwave irradiation to enhance reaction between SA and nitrite in a short time, in which nitrite in wastewater was completely converted into nitrogen gas without leaving any sludge and secondary pollutants.

Manual composite sampling in edge-of-field surface runoff for assessing nonpoint source pollution from agricultural lands and residential areas

While there are several surface water quality sampling techniques such as flow-interval, time-interval, and composite sampling, it is still a challenging task to select the appropriate sampling technique for edge-of-field surface runoff water quality monitoring. We hypothesized that manual composite sampling gives comparable results with discrete flow-paced sampling for edge-of-field surface runoff water quality. We collected discrete flow-paced and manual composite surface runoff water samples from sugarcane (<i>Saccharum officinarum</i> L.) fields, pasture lands, and residential areas from October 2002 to October 2003 and analyzed for total suspended solids (TSS), total combustible solids (TCS), five-day Biological Oxygen Demand, nitrate/nitrite-nitrogen (NO₃/NO₂-N), soluble reactive phosphate (SRP), total phosphorus (TP), total nitrogen (TN), and pH in the Vermilion-Teche River Basin in Southwestern Louisiana. Overall, compared to the flow-paced sampling, average five-day Biological Oxygen Demand, TSS, TCS, SRP, TP, NO₃/NO₂-N, and TN concentrations using composite sampling were lower by 4.3%, 8.1%, 8.2%, 9.5%, 4.1%, 36.8%, and 8.2%, respectively. As expected, the constituent concentrations with the flow-paced sampling and the composite sampling were significantly (α = 0.05) positively correlated. Although TSS, TCS, and SRP concentrations slightly declined with flow levels and TP, NO₃/NO₂-N, and TN concentrations showed a general trend of slight increase from 15,142 L (4,000 gal) to 227,125 L (60,000 gal), correlation analysis of the pooled dataset showed no significant correlation (α = 0.05) between flow level and water quality constituents in this study. Similarly, no significant differences were found on event loads of TSS, TCS, SRP, TP, NO₃/NO₂-N, and TN calculated from flow-paced sampling and manual composite sampling strategies. Therefore, manual composite sampling is suggested over flow-paced sampling for edge-of-field water quality monitoring in agricultural lands and residential areas because, while producing comparable results, it reduces the cost of laboratory determination.

Starting-up and operating a full-scale activated sludge system for slaughterhouse wastewater

This research was conducted at the Frigofrontera wastewater plant which has screening, de-sanding, a grease trap and sedimentation as its primary treatment system, an activated sludge recirculation reactor for secondary treatment and a descending bed filter for tertiary treatment. Average treated flow is 1.38 L/s; the activated sludge reactor has a 144 m3 volume and 2-day cell retention time. Reactor oxygen levels are guaranteed by injecting air using high-efficiency equipment. Basic wastewater concentration parameters are: 5,242.13 mg / L BOD5; 9,039.75 mg / L COD and 2,972.69 mg / L SS. The treatment plant was started up during February 2006 and has been in constant operation since then. It has achieved 89.73% five-day biological oxygen demand (BOD5), 89.03% chemical oxygen demand (COD) and 94.09% soluble solid (SS) load removal efficiency. The sludge produced by the process is treated by screening where the solids are separated from wastewater. The liquid is returned to the sedimenters and solids are composted.

Treatment of polluted river water by a gravel contact oxidation system constructed under riverbed

The objective of this study was to evaluate the treatment efficiency of a gravel contact oxidation treatment system which was newly constructed under the riverbed of Nan-men Stream located at the Shin Chu City of Taiwan. The influent and effluent water samples were taken periodically for the analyses of pH, temperature, dissolved oxygen, total suspended solids, five-day biological oxygen demand, NH4 +-N. The results showed that the average removal rates of five-day biological oxygen demand, total suspended solids and NH4 +-N were 33.6% (between −6.7% and 82.1%), 56.3% (between −83.0% and 93.4%) and 10.7% (between −13.0% and 83.3%), respectively. The calculated mean first order reaction rate constant for five-day biological oxygen demand was 4.58/day with a standard deviation of 4.07/day and for NH4 +-N was 2.15/day with a standard deviation of 5.68/day. Therefore, it could be said that this gravel-contact-oxidation system could effectively remove biological oxygen demand, total suspended solids, and NH4 +-N in river water at a relatively short hydraulic retention time, although its pollutant treatment efficiency was not quite stable. However, to reach better or more stable treatment efficiency, aeration might sometimes be necessary to increase the dissolved oxygen in influent river water. And, longer hydraulic retention time of the system might also be required to increase NH4 +-N removal efficiency.

Year-round treatment of dairy wastewater by constructed wetlands in Atlantic Canada

Constructed wetlands are used throughout North America to treat various types of wastewater in warm climates; however, little has been documented about their treatment processes and efficiencies during winter periods in Atlantic Canada. Two small-scale constructed wetlands (100 m2) of differing operational depth (wetland 1: 0.15 m shallow zone depth and wetland 2: managed water level) were designed to treat agricultural wastewater at the Bio-Environmental Engineering Center of the Nova Scotia Agricultural College. Both wetlands were monitored from November 2000 through March 2002 to evaluate treatment efficiencies and mass reductions of five-day biological oxygen demand (BOD5), total suspended solids (TSS), total phosphorus (TP), and ammonia-nitrogen (NH3-N). An average loading rate of 44.7 kg BOD ha−1 d−1 was loaded into each wetland, even during winter months. Percent removal and mass reductions for BOD5, TSS, TP, and NH3-N in both wetlands, irrespective of water levels, ranged from 62 to 99%. The treatment of TP was not found to be as effective as the other parameters, especially during high loading periods. Results show promise for the operation of constructed wetlands on a year-round basis in Atlantic Canada.

An integrated constructed wetland to treat contaminants and nutrients from dairy farmyard dirty water

Water pollution by agriculture can include inappropriately managed dairy farmyard dirty water. In Ireland, dairy farmyard dirty water includes farmyard runoff, parlour washings, and silage/farmyard manure effluents. The objectives of this study were to determine (i) the quality and quantity of dirty water generated at a farm-scale and (ii) the seasonal effectiveness of a constructed wetland to treat farmyard dirty water. The wetland system was 4800 m 2 in area and treated dirty water from a 42-cow organic dairy unit with an open yard area of 2031 m 2. Monthly dirty water inflow rate to the wetland ranged between 3.6 and 18.5 m 3 d −1. Farmyard dirty water accounted for 27% of hydrological inputs to the wetland, whereas rainfall on wetland, along with wetland bank inflows accounted for 45 and 28%, respectively. Farmyard dirty water quality and quantity did not vary with season. Yearly mass loads discharged to the wetland were 47 ± 10 kg yr −1 of soluble reactive phosphorus (SRP), 128 ± 35 kg yr −1 of NH 4 +, 5484 ± 1433 kg yr −1 of organic material as measured by five-day biological oxygen demand (BOD 5), and 1570 ± 465 kg yr −1 of total suspended solids (TSS). Phosphorus retention by the wetland varied with season (5–84%) with least amounts being retained during winter.

Effects of aeration on water quality from septic system leachfields.

We conducted a pilot-scale study at a research facility in southeastern Connecticut to assess the effects of leachfield aeration on removal of nutrients and pathogens from septic system effluent. Treatments consisted of lysimeters periodically aerated to maintain a headspace O(2) concentration of 0.209 mol mol(-1) (AIR) or vented to an adjacent leachfield trench (LEACH) and were replicated three times. All lysimeters were dosed with effluent from a septic tank for 24 mo at a rate of 12 cm d(-1) and subsequently for 2 mo at 4 cm d(-1). LEACH lysimeters had developed a clogging mat, or biomat, 20 mo before the beginning of our study. The level of aeration in the AIR treatment was held constant regardless of loading rate. No conventional biomat developed in the AIR treatment, whereas a biomat was present in the LEACH lysimeters. The headspace of LEACH lysimeters was considerably depleted in O(2) and enriched in CH(4), CO(2), and H(2)S relative to AIR lysimeters. Drainage water from AIR lysimeters was saturated with O(2) and had significantly lower pH, five-day biological oxygen demand (BOD(5)), and ammonium, and higher levels of nitrate and sulfate than LEACH lysimeters regardless of dosing rate. By contrast, significantly lower levels of total N and fecal coliform bacteria were observed in AIR than in LEACH lysimeters only at the higher dosing rate. No significant differences in total P removal were observed. Our results suggest that aeration may improve the removal of nitrogen, BOD(5), and fecal coliforms in leachfield soil, even in the absence of a biomat.

Activated sludge biotreatment of sulphurous waste emissions

Odours from wastewater treatment plants are comprised of a mixture of various gases, of which hydrogen sulphide (H2S) is the main constituent. Sulphurous compounds can be degraded by microorganisms commonly found in wastewater. The use of activated sludge (AS) diffusion as a dual-role system, for the treatment of wastewater and for odour control, offers an alternative to traditional sulphurous waste gas treatment processes, such as biofilters, bioscrubbers and biotrickling filters, both in practical terms (use of existing facilities) and economically (minimal capital cost). Activated sludge diffusion avoids the common problems associated with these processes such as media plugging, excess biomass accumulation, gas short-circuiting, and moisture control and maintaining the correct biofilm thickness. The design issues to be considered when using AS diffusion for odour abatement, comprise odourous air pre-treatment,blowers and diffuser types, corrosion protection and increase in odour emission intensity. Nitrification inhibition depends on the composition and acclimation of the biomass, the concentration of H2S and other components of the wastewater. Hydrogen sulphide removal rates of >98% were consistently achieved for loads of 3–34 mg H2S/g MLSS/h, in two case studies, which also showed that sludge type has an impact on the ability of the sludge to degrade H2S. Wastewater process performance measured as five-day biological oxygen demand (BOD5), chemical oxygen demand (COD) and effluent suspended solids removal was not affected by H2S diffusionat 5 ppm. A change in the microorganism population dynamics of anactivated sludge was observed when it was exposed to H2S for aperiod of more than 21 days.

Scanning optical sensor for the measurement of dissolved oxygen and BOD

A scanning optical sensor based on the oxygen quenching of luminsescence has been developed for the measurement of dissolved oxygen and five-day biological oxygen demand (BOD 5). the sensing is a silicone rubber film with embedded ruthenium(II) complex. It is attached to the inner surface of a transparent vessel in whcih dissolved oxygen needs to be measured. An optical scanner with an exitation light source and an optical cable connected to a light detector are used to monitor the oxygen concentration inside the vessel. The scanner provides the excitation light and senses the emitted light from the sensing element without direct physical contact with the vessel. Therefore, one optical scanner can be used to monitor the dissolved-oxygen concentration in many vessels in one batch. A correlationis found for linearizing the responses of luminescence quenching with the dissolved-oxygen concentration, which enable two-point calibrations of the sensors to be carried out. Effects of temperature and steam sterilization on the sensor are also studied.

The response of Moina brachiata (Jurine) 1820 to biological oxygen demand, oxygen, and light

A steady-state gradient apparatus was used to study population dynamics and to investigate chemical, physical, and behavioral characteristics influencing populations. Preferential localization of the cladoceranMoina brachiata (Jurine) was observed within the experimental gradient. Laboratory and field studies suggest thatM. brachiata responds to light as a discriminated stimulus when light is paired with a reinforcer, food. The cladocerans preferred as a medium water having a five-day biological oxygen demand (BOD) of approximately 14–16 ppm. Preference for BOD levels appears to be more restrictive than preference for levels of dissolved oxygen. The relationship of space and time with respect to ponds and gradient is discussed.