BOD Loading Rates Research Articles

Biosorption of LMW PAHs on activated sludge aerobic granules under varying BOD loading rate conditions

Polycyclic aromatic hydrocarbons belong to the main priority substances for the aquatic environment. One of the emission sources of these compounds to environment is wastewater discharged from conventional wastewater treatment systems, which are not designed to cope with this type of pollution. Thus, due to the widely discussed properties of aerobic granular activated sludge in the literature – a conducted study has proven its ability to remove LMW PAHs (naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), phenanthrene (Phe) and anthracene (Ant)) from wastewater by biosorption process at varying loadings of organic compounds expressed as BOD (kg/kg·d) on the activated sludge mass. The maximum biosorption of Nap was 605 µg/kgd.m., Acy equals to 134 µg/kgd.m., Ace equals to 355 µg/kgd.m. Flu equals to 104 µg/kgd.m. Phe equal to 204 µg/kgd.m. and Ant equal to 173 µg/kgd.m. The study showed that the BOD loading rate is one of the factors affecting the biosorption process of LMW PAHs. However, as the amount of adsorbed LMW PAHs increased, the condition of aerobic granular activated sludge deteriorated, which was evidenced by gradual increase in the values of technological parameters of activated sludge (SVI, HRT, SRT) and a smaller increase in activated sludge dry mass.

Artificial neural network approach to modelling of HMW PAHs removal under fluctuating BOD loading rate in anaerobic and aerobic phases of GSBR reactor

Artificial neural network approach to modelling of HMW PAHs removal under fluctuating BOD loading rate in anaerobic and aerobic phases of GSBR reactor

GIS Water Quality Simulation Study: Chinchuba Watershed

The purpose of the study is to enhance the watershed management for St. Tammany parish, LA through development of a model that will account for water quality impacts. Bayou Chinchuba in St. Tammany parish Louisiana is selected for this water quality model. Developed with HSPF (Hydrologic Simulation Program in Fortran), the model is used to calculate NO3, PO4, and BOD loading rates for varying scenarios of land use development. GIS tools are used to determine, visualize, and compare the total loads generated within sub-basins of the watershed based on the model simulation results. With the GIS calculation of NO3, PO4, and BOD total load and visualization enhancement, this tool simulates existing conditions and compares the water quality impact to 2020 expectation values.

Design Evaluation of Biological Unit as a Basic Consideration to Determine the Design Criteria of Domestic Wastewater Treatment Plant at 1st Zone, Jakarta

The evaluation of existing Wastewater Treatment Plant (WWTP) is doing by evaluate the performance and design of biological unit. On design planning of WWTP, the biological process unit is the key role to reach the target of pollutant removal efficiency. The optimum design parameter of biological process unit could be attained from the real condition by doing evaluation of existing WWTP as a comparison. The selection of an appropriate existing WWTP is based on the similarity of region characteristic, typical activities of people who use the water and wastewater quality and characteristic, and it match to Tana Tinggi WWTP. Tana Tinggi WWTP has capacity 63.8 L/s that already serve 2785 home connections system or 77% of serving area of Tangerang City. The process and operation units are consist of screening, activated sludge, clarifier and sludge handling system. The evaluation of activated sludge gives the data that BOD loading rate is 0.32 Kg/m3.day, MLSS is 3920 mg/L, F/M ratio is 0.036 kg BOD/kg MLSS.day, hydraulic retention time (HRT) is 6.78 hours and sludge age is 5.16 days. From the evaluation results there are three parameters that can be determine as design criteria and will be apply for design of biological process unit. The parameters are MLSS 3900 mg/L, HRT 6 hours and sludge age 5 days. In otherwise, the F/M ratio doesn’t prove the appropriate value and it show that the activated sludge of existing WWTP is leak of nutrition that is necessary for microorganism metabolism.

Assessment of biological trickling filter systems with various packing materials for improved wastewater treatment

Attached growth processes for wastewater treatment have significantly been improved during recent years. Their application can be extended to sustainable municipal wastewater treatment in remote locations and in developing countries for the purpose of organic matter (biochemical oxygen demand, BOD) removal and pathogenic decontamination. The aim of this study is to assess selected packing media for biological trickling filters (BTFs) and to develop a simplified model for describing the capacity of BOD removal in BTFs. In this work, BTFs with four different media viz., rubber, polystyrene, plastic and stone have been investigated at two temperature ranges of 5–15°C and 25–35°C. The average removal of both chemical oxygen demand and BOD was higher than 80 and 90% at temperature ranges of 5–15 and 25–35°C, respectively. The geometric mean of faecal coliforms in BTF using polystyrene, plastic, rubber and stone as filter media was reduced by 4.3, 4.0, 5.8 and 5.4 log10, respectively, at a low temperature range of 5–15°C. At a higher temperature range of 25–35°C, the faecal coliform count was reduced by 3.97, 5.34, 5.36 and 4.37 log10 from polystyrene, plastic, rubber and stone media BTF, respectively. Simplified model was developed and used to estimate the optimal BOD loading rates (Bvd) for designing robust BTF systems, with appropriate filter media. It has been concluded that highly efficient BTFs can be designed using various filter media, which may be capable of treating organic loading rates of more than 3 kg BOD/m3 day. These types of BTFs can be applied for the BOD and microbial contaminants removal of wastewater for potential reuse in developing countries.

Contribution of Non-Point Pollution to Water Quality and Runoff Characteristics from Agricultural Area of the Upstream Watersheds of Lake Chinyang

In this study, non-point source(NPS) contribution was investigated based on flow rates and water qualities of streams into the lake during rainfall events. Event mean concentration(EMC) and the pollution loads were calculated to establish a database for NPS control measurement in the survey area, and so on. The runoff characteristics of NPS were investigated and estimated on the basis of the ratio of an agricultural to forest area in the stream of sub-catch basin during rainfall events. Non-point source pollution loads were also calculated to establish a database for NPS control measure in the upstream lake Chinyang. At a rainfall event, BOD concentrations rise sharply at the early peak time of runoff, however, peaks of TSS concentration were observed at the similar time of peak flow. This was a phenomenon shown at the watersheds caused by forest and geological types. The discharged EMC range was 2.9-4.8 mg/L in terms of BOD. The discharged EMC range was 6.2-8.2 mg/L in terms of SS. The discharged EMCs of T-N and T-P were 1.4-2.5 mg/L and 0.059-0.233 mg/L, respectively. Total BOD loading rate through the 3 tributaries to the lake Chinyang was 1,136 kg/d during dry weather. The upper watershed area of the Nam-river dam in this study was divided into 14 catchment basins based on the Korean guideline for total maximum daily load(TMDL) of water quality pollutants. The higher the agricultural land-use ratio, the more NPS loading rate discharged, but the more occupied a forest area, the lower more NPS loading rate discharged. In an agricultural land-use area more than 20%, the increase of NPS loadings might be dramatically diffused by increasing the integrated complex-use like vinyl-house facilities and fertilizer use etc. according to the effective land-use utilization. The NPS loading rates were BOD 0.3 <TEX>$kg/ha{\cdot}day$</TEX>, SS 0.21 <TEX>$kg/ha{\cdot}day$</TEX>, TN 0.02 <TEX>$kg/ha{\cdot}day$</TEX>, TP 0.005 <TEX>$kg/ha{\cdot}day$</TEX> under less than 10% agricultural land-use. In agricultural land-use of 20%-50%, these values were investigated in the range of 0.32 <TEX>$kg/ha{\cdot}day$</TEX>-0.73 <TEX>$kg/ha{\cdot}day$</TEX> for BOD, 0.92 <TEX>$kg/ha{\cdot}day$</TEX>-3.32 <TEX>$kg/ha{\cdot}day$</TEX> for SS, 0.70 <TEX>$kg/ha{\cdot}day$</TEX>-0.90 <TEX>$kg/ha{\cdot}day$</TEX> TN, 0.03 <TEX>$kg/ha{\cdot}day$</TEX>-0.044 <TEX>$kg/ha{\cdot}day$</TEX> for TP.

Woven Fabric Bioreactor (WFBR) as the Filter Material for Wastewater Treatment

Conventional and modified membrane bioreactors (MBRs) are effective increasingly used in small sized wastewater treatment plant. However, their widespread applications are hindered by their elevated energy consumption and the high costs of investment for the membrane modules. In this study, we investigated a modified an improved MBR system that utilized a cost effective woven fabric instead of nonwoven as the filter material in MBR modules. The woven fabric bioreactor (WFBR) system was operated in a continuous mode at HRT from 33 to 12h. Under the operational conditions of BOD loading rates from 0.12 to 0.28 kg BOD/kg MLSS /d, the WFBR system was able to reduce up 93.57% COD. The 38μm woven fabric performed well in solid-liquid separator, with an average suspended solids retention of 99.47% at MLSS of 4710~9951 mg/L. The WFBR system eliminated suction pumping by using a gravity head in the membrane filtration of the effluent over the entire operational period of 60 d.

Septic Tank Effluent Treatment by Subsurface Horizontal Flow Wetland

Domestic wastewater treatment in Indonesia, mostly treat by using septic tanks. The use of septic tanks preferred by the public because of the design, construction, and maintenance are easy and more economical for the system of domestic wastewater disposal. Effluent from the septic tank still contains BOD about 100 mg /l, COD about 250 mg/l and TSS about 100 mg /l. This effluent is still dangerous to public health and is not fulfill wastewater effluent standards yet. If there is open space available, extended treatment of septic tank effluent can be done by field infiltration. This open space must suitable for infiltration without contaminating the ground water or well water. In urban areas with ground water level is high such as Surabaya, water infiltrate into the ground causing the problem. Problems that arise are due to pollution of ground water and surface water contaminated by effluent from the septic tank. Because of these problems, it would require an alternative treatment of septic tank effluent. Appropriate technology would be a simple, economical, easy in operation and maintenance. One of wastewater processing that can be applied to the septic tank effluent is a constructed wetland system. Previous research carried out by using Cyperus papyrus plant with sand media in batch experiments showed satisfactory results. In this study, experiments conducted by using Cyperus papyrus plant with sand media with continuous flow in a horizontal subsurface flow wetland method. Wastewater flows with varying flow 90 ml /min and 180 ml /min. The objective of this research is to determine the ability of a horizontal subsurface flow wetland for treating septic tank effluent. The parameters analyzed were BOD and TSS. The results show the relation of organic loading rate with BOD removal efficiency. The highest organic loading rate of 0.051 kg BOD/m2.d on first day observations has BOD removal efficiency of 73.63% and the lowest organic loading rate of 0.029 kg BOD/m2.d with an efficiency of 70.82%. This shows that BOD removal efficiency is affected by organic loading rate. If BOD loading rate increase, it will decrease BOD removal efficiency. Organic loading rate recommended for domestic wastewater is 0.037-0.4 kg BOD5 /m2.d. Although in this study the organic loading rate exceeds the above recommendations, but efficiency is still good, above 70%.

Assessment of classical surface organic loading design equations based on the actual performance of primary and secondary facultative ponds

This article presents results from a performance evaluation of 73 full-scale primary facultative ponds and 37 secondary facultative ponds in Brazil. The data were used to test the applicability of some classical design equations for recommended surface BOD loading rates. The empirical equations proposed by Mara in 1976 and 1987 and the equation developed by McGarry and Pescod in 1970 were evaluated. The loading and hydraulic operating conditions were also evaluated to support the analysis of the influence of the parameters surface BOD loading (L(s)) and hydraulic retention time (HRT) on the performance of the ponds. The results showed that the design equations proposed by Mara showed good applicability for primary facultative ponds, representing good indicators of the limit value of loading rates to be applied on the units. But the secondary facultative ponds showed good and poor performances for all loading rates and the best ponds, in general, were not those which followed the design equations recommendation. Finally, the influence of the actual loading conditions on the ponds performance was very small and scattered, indicating that other unquantified design and operational aspects were playing an important role.

Sustainable nitrogen removal from wastewater with the hybrid membrane biofilm process (HMBP): bench-scale studies

The hybrid membrane biofilm process (HMBP) is a novel approach to achieving total nitrogen removal from wastewater. It incorporates air-supplying, hollow-fiber membranes into a conventional activated sludge tank, where bulk aeration is suppressed. A nitrifying biofilm grows on the membranes and exports nitrite and nitrate to the anoxic bulk liquid, where suspended heterotrophic bacteria denitrify using influent BOD as an electron donor. Bench scale tests were used to assess the performance of the HMBP for a variety of nitrogen and BOD loading rates. For a nitrogen loading of 1.6 gN m(-2), the nitrification flux remained at approximately 1.0 gN m(-2) d(-1) for BOD loadings ranging from 4 to 17 gBOD m(-2) d(-1) day(-1). Full denitrification was achieved when sufficient BOD was available in the influent. Microsensor measurements indicated nitrite was the dominant form of oxidized nitrogen produced by the biofilm, showing that shortcut nitrogen removal was taking place. Fluorescence in-situ hybridization (FISH) tests on the biofilm revealed a unique stratification, with three distinct regions: AOB and NOB near the membrane, strictly AOB at intermediate depths, and AOB and heterotrophs at the outer edge of the biofilm.

THE PERFORMANCE OF PILOT‐SCALE PRIMARY‐FACULTATIVE WASTE‐STABILISATION PONDS IN THE UK

ABSTRACTThree pilot‐scale primary‐facultative waste stabilisation ponds were constructed at Esholt sewage‐treatment works, Bradford. Each pond received screened sewage at different BOD loading rates over a two‐year period. Concentrations of BOD, SS, amm. N and chlorophyll‐a were measured weekly in summer and bi‐weekly in winter, and sludge accumulation was measured after 3, 9, 15 and 20 months. BOD and SS removals were consistently high, although they were lower in summer than in winter due to high levels of algae. The removal of amm, N was generally much better in summer than in winter ‐ the removal mechanism being most likely related to algal activities. Sludge accumulation rates were very low.

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

DOMESTIC WASTEWATER TREATMENT USING IMMOBILIZED SLUDGE FLUIDIZED-BED REACTORS

Bench-scale fluidized-bed reactors using the immobilized activated sludge process were studied for the treatment of domestic wastewater. Different intermittent aeration patterns were investigated in order to improve the total nitrogen (TN) removal. The best TN removal at 74.4% was achieved at an HRT of 6 hours (with corresponding BOD loading rate of 0.766 kg/m3/d) and an aeration-pattern of 1,3 (the hours of aeration and non-aeration time cycle). The removal efficiencies for organic carbon, NH+ 4 -N, TKN and TSS were not affected and remained at more than 90%. Simultaneous organic carbon and nitrogen removal was accomplished in a single immobilized sludge reactor. The impact of various influent feed patterns on the treatment was examined. The continuous feed pattern was recommended as it ensured good TN removal without any adverse impacts on the removal of organic carbon, NH+ 4 -N, TKN and TSS. The immobilized sludge beads exhibited satisfactory mechanical stability without apparent breakage over the 180-day experiment period.

Wastewater treatment using activated sludge entrapped in polyethylene glycol prepolymer

Immobilized activated sludge was applied to the treatment of organic wastewater discharged from a semiconductor plant. To enhance the treatment efficiency, the growth characteristics of heterotrophic bacteria and the effect of the BOD loading rate in continuous wastewater treatment by the immobilized activated sludge were investigated. The activated sludge was entrapped in polyethylene glycol (PEG) prepolymer pellets. Wastewater with a BOD of 150–200 mg/ l was continously treated in a 200- l capacity prototype reactor. The effluent BOD concentration after treatment was 10 mg/ l or less at a loading rate of a 5.21 kg-BOD/m 3·d, representing BOD removal of 95–97%. The layer of heterotrophic bacteria in a pellet was 300 μm in depth, which was thicker than that of immobilized nitrifying bacteria fed on domestic wastewater.

Virus removal by the domestic wastewater treatment system named Johkasou

Virus removal by a treatment plant for domestic wastewater (Johkasou), was investigated using a small model of the plant. Under standard BOD loading of 0.076 BOD kg/m3/day, 97% of E. coli phage T2, 98% of poliovirus 1 and 93% of coxsackievirus B3 were removed from inlet wastewater by the system. About 80% of the viruses in the influent were removed in the first and second anaerobic zones under the standard conditions. When the loading was increased to double the standard loading (0.152 kg BOD/m3/day) the removal rate decreased to 64%. Poliovirus 1 and coxsackievirus B3 were removed more easily than T2 phage. Assuming the stream in each zone was completely mixed, the virus reducing activity of microorganisms was estimated by the rate constant of the first order reduction equation. It was found that the higher the BOD loading rates, the lower the values of the constant.

Virus removal by the domestic waste water treatment system named johkasou

Virus removal by a treatment plant for domestic wastewater (Johkasou), was investigated using a small model of the plant. Under standard BOD loading of 0.076 BOD kg/m3/day, 97% of E. coli phage T2, 98% of poliovirus 1 and 93% of coxsackievirus B3 were removed from inlet wastewater by the system. About 80% of the viruses in the influent were removed in the first and second anaerobic zones under the standard conditions. When the loading was increased to double the standard loading (0.152 kg BOD/m3/day) the removal rate decreased to 64%. Poliovirus 1 and coxsackievirus B3 were removed more easily than T2 phage. Assuming the stream in each zone was completely mixed, she virus reducing activity of microorganisms was estimated by the rate constant of the first order reduction equation. It was found that the higher the BOD loading rates, the lower the values of the constant.

米焼酎蒸留廃液の生物処理

A treatment process of waste water discharged from rice shochu distillery with yeasts and activated sludges was developed.he solid-liquid separation of the distillery waste water was carried out effectively by adding a filtration aid and Geotrichum M 111 cells, which showed the ability of accelerating the aggregation of insoluble solid in the waste water. The dehydration test of aggregated waste water was made using a belt press-type dehydrator, and the best filtration rate of 33kg/m·hr was obtained. The separated filtrate was treated with the waste-treating yeast strain, Hansenula anomala J-45-0 and 70% of BOD was removed. In addition, to remove the solid, the filtrate was subjected to the yeastlytic bacteria, Rarobacter faecitabidus, which have lytic-ability against the strain J-45-0. Through this treatment, about 40% of solid was removed from yeast treated water. The waste water treated with Rarobacter faecitabidus was diluted to ca. 5-10 times with water and subjected to the activated sludge treatment. The concentration of BOD in the treated waste water was decreased to be less than 30 ppm at the condition of a volumetric BOD loading rate of 0.4-1.0kg/m3·d. As the result, the waste water discharged form rice shochu distillery was clarified by the continuous process of biological treatments.

紙・パルプ廃水の嫌気性処理 アクアルネッサンス’９０の成果

A study on anaerobic bioreactor using Kraft pulp mill wastewater was performed with UF membrane separation process. The system consisted of pretreatment equipment for oil separation, a stripping system for sulfur compounds, an anaerobic bioreactor for methane fermenation, membrane module equipment for bacterial concentration, and a gas treatment system. The bioreactor had a fixed-bed with an effective volume of 5 m3 packed with pumice stone.In continuous run with the membrane module system, the HRT was 12 hours, maximum BOD loading rate was 35 kg-BOD/m3/day, and maximum BOD removal rate was 93%. Highly efficient continuoud operation was attained with concentration of useful bacteria by the membrane.And, we have also made trial calculation of costs for methane fermentation.

Performance of a New Equipment for Treating Domestic Wastewater

A fixed-bed aeration reactor system was developed for on-site and small-scale wastewater treatment. The reactor was packed with horizontal plates as support materials. There was no clarifier in the system. Three operational regimes were tested, which were a 6 hours total cycle, 8 hours total cycle and 12 hours total cycle. Experimental results showed the reactor can treat household wastewater efficiently. Removal efficiencies of BOD and SS were 88% for the BOD loading rate of 0.12 kg-BOD/m3·d or 5.2 g-BOD/m2·d. Effluent BOD and SS concentrations were means of 18 mg/l and 6 mg/l during the whole time operation. Suspended solids efficiently sedimented on the horizontal support plates in a short settling time. Equations were developed to predict BOD consumption and sludge production as a function of influent soluble BOD and suspended solids. Useful design and operating parameters are identified for future evaluations of the fixed bed aeration reactor.

Effects of Organic Nutrient Strength on the Purple Nonsulfur Bacterial Content and Metabolic Activity of Photosynthetic Sludge for Wastewater Treatment

Changes in the purple nonsulfur bacterial content and metabolic activity of photosynthetic sludge in response to wastewater strength in a practical plant and in laboratory-scale batch reactors were investigated. Both plant and laboratory systems yielded large quantities of purple nonsulfur bacteria, as many as 10 7 viable cells·mg dry sludge −1, when loaded with high biological oxygen demand (BOD) levels of wastewater containing acetate as a major BOD source. Experiments with laboratory reactors showed that the phototrophic bacteria could keep occurring in such large numbers at BOD-loading rates higher than 0.8 kg BOD·kg dry sludge −1·d −1. The loading of high BOD wastewater also enhanced oxygen uptake activity with lower fatty acids used as substrates, as well as the enzyme activities of the tricarboxylic acid cycle of the sludge. However, there was no difference in the enzyme activities of the glyoxylate pathway between high BOD-loaded and low BOD-loaded sludges. The results obtained suggest that wastewater strength, especially a lower fatty acid concentration, is one of the most important factors affecting the viability and activity of purple nonsulfur bacteria in the photosynthetic sludge process.