Biochemical Oxygen Demand Concentrations Research Articles

Analysis of Faecal Sludge Treatment Alternatives to Enhance the Treatment Performance of Wastewater Treatment Plant (WWTP) Denpasar Sewerage Development Project (DSDP) Suwung Denpasar City

Most of the wastewater generated from domestic activities in Denpasar city is treated in an off-site treatment plant located in WWTP DSDP Suwung. This includes faecal sludge that originates from on-site treatment plants. The existing treatment facilities can only treat wastewater that has a maximum biochemical oxygen demand (BOD) concentration of around 225 mg/l while the disposed faecal sludge’s BOD concentration reaches 3,394 mg/l. Therefore, an additional faecal sludge treatment plant needs to be established in order to separate the solid phase from the liquid phase. According to the treatment performance calculation, some alternative treatments can achieve BOD5 and TSS removal of up to 97% and 98% respectively. The selection of the alternative treatment was decided from weighting results of several aspects, such as economic, land use, technological and environmental aspects. The weighting method that was used in this research was Simple Additive Weighting (SAW). The advantage of SAW is its ability to do the assessment highly precisely because it is based on predetermined criteria and preference weights. Based on the weighting result, the treatment technology selected was a Solid Separation Chamber as primary treatment, combined with an Anaerobic Baffled Reactor as a secondary treatment. A Belt Filter-Press was applied to reshape the sludge into a recyclable cake. The required cost is approximately 16 billion rupiahs.

Coliforms removal efficiency of Wupa wastewater treatment plant, Abuja, Nigeria

Efficient wastewater treatment is critical to the sustainability of the environment and protection of public health, and wastewater treatment plants. This study thus, investigates the coliforms removal efficiency of Wupa wastewater treatment plant, Abuja, Nigeria over a period of five consecutive years (2013–2017). The study was conducted using secondary data on average annual characteristics of raw sewage (influent) and treated wastewater (effluent) of the wastewater treatment plant. The correlation between the coliforms removal efficiency and other wastewater constituents such as biochemical oxygen demand, chemical oxygen demand, total suspended solid and E.coli were also explored using paired sample mean t-test static at 5% level of significance (P<0.05. The outcome of this study indicated a total coliform and E.coli removal efficiency ranging between 99.96% to 99.98%, and 87% to 99.97% respectively; with the year 2017 notably having the highest Total Coliform and E.coli removal efficiency of 99.98% and 99.7% respectively. The findings of the research also revealed that in the t-test statistical analysis t-test value of t-critical is less than the value of t-statistic which means that there is strong relationship between the following wastewater constituents; biochemical oxygen demand concentration and Fecal coliform, total suspended solids, E.coli, total coliform and fecal coliform with (p < 0.05) confidence value. In conclusion, the observed coliforms removal efficiency in this study (97% to 99.98%) indicates a high removal efficiency which gives credence to several previous similar studies which reported coliform removal efficiencies of over 90%. The coefficient of correlation (r2) obtained from the research ranges between 0.49 and 0.97.

Modeling Spatial Patterns of Dissolved Oxygen and the Impact Mechanisms in a Cascade River

Dissolved oxygen (DO) concentration is an essential indicator for assessment of river ecosystems. A hydrodynamic and water quality mathematical model coupling one-dimensional and two-dimensional models is developed in this study. The characteristics of study area, flow velocity, temperature, and organic contamination are taken as consideration in the scenario setting. The changing processes of DO concentration are simulated in different scenarios, and the effects on DO concentration are discussed. Results indicate that: 1) A negative relation was present between DO concentration in Yongjiang River and releasing discharge of the Laokou hydro-project, since reoxygenation is greater than oxygen consumption along the river, DO concentration increases from upstream to downstream. 2) DO concentration increases with the releasing of DO in the water, which also varies along with the releasing of biochemical oxygen demand (BOD) concentration. Laokou exhibits the greatest increase of BOD, which ranges from 0.1 mg/L to 0.75 mg/L 3) The increasing of water temperature results in increased reoxygenation and a decrease in oxygen consumption. Our study shows that the water temperature increased from 19°C to 29 °C, and correspondingly saturated DO decreased from 9.25 mg/L to 7.54 mg/L. The study provides scientific support for ecology operation in the cascade river, and is expected to improve the water environment by reservoir regulation.

Energy savings with a biochemical oxygen demand (BOD)- and pH-based intermittent aeration control system using a BOD biosensor for swine wastewater treatment

Intermittently aerated activated sludge processes save energy by minimizing the total aeration time per day without deteriorating effluent water quality. Swine wastewater contains high, often widely fluctuating concentrations of biochemical oxygen demand (BOD) and nitrogen. BOD-based aeration control would therefore be a useful method to reduce the energy demands of aeration, but requires a reliable BOD sensor for swine wastewater. In this study we developed a novel approach for BOD- and pH-based intermittent aeration control (BAC) using a BOD biosensor based on exoelectrogenic bacteria and tested it at four swine wastewater treatment plants. This BAC system reduced aeration energy in the plants by 15–36% compared to fixed aeration cycle operations while maintaining low concentrations of BOD and total nitrogen in the effluent. The energy saved per wastewater volume was 477–1012 kWh/m3/yr, equivalent to a reduction of 2.2–7.0 t-CO2/m3/yr in greenhouse gas emissions. The biosensor was equipped with an internet connection to allow for remote monitoring of water quality data with a smartphone, saving labour in the operational management of the plants. Aquabacterium and the aerobic denitrifier Thauera were detected as the predominant genera in the activated sludge.

Modeling and numerical simulation of dissolved oxygen and biochemical oxygen demand concentrations with Holling type III kinetic relationships

Mathematical models have been widely used for the study of water quality. Regarding the pollution of water resources by organic matter, dissolved oxygen (DO) and biochemical oxygen demand (BOD) are important indicators for their monitoring. In this way, this research presents a two-dimensional mathematical model in space that evolves over time, for the study of the variations in concentrations of these variables, through a coupled system of non-linear partial differential equations, with Holling type III reaction kinetics between DO and BOD. Under some simplifications, the stability of the equilibrium points of the model is analyzed. An approximate solution is proposed using the centered finite difference (CFD) method for spatial variables and the Crank–Nicolson method for the temporal variable. An upwind scheme was employed in the advective-term discretization. Computer simulations were performed using Matlab software, in a rectangular domain. For the advective transport, the influences of the wind and the current given by a parabolic profile were considered. We performed a series of space-time numerical simulations and found that the model allows the analysis of regions with higher and/or lower DO and BOD concentrations, as well as the temporal variations of concentrations at specific points in the domain, and the influence of diffusive-advective transport in the mass transfer process.

Pengaruh Dosis Serbuk Biji Kelor (Moringa Oliefera) Terhadap Kadar Biochemical Oxygen Demand Air Limbah Rumah Pemotongan Ayam Tahun 2021

Abstract: Biochemical Oxygen Demand (BOD) levels in home industry of Chicken Slaughterhouse’s wastewater that exceed the standard are discharged into water which will cause environmental pollution and will decrease in dissolved oxygen content in waters which can result in the death of aquatic organisms. The results of measuring BOD levels in Chicken Slaughterhouse, UD Giri Sari wastewater obtained an average of 814.78 mg/L which exceeds the quality standards of the Regulation of the Minister of Environment of the Republic of Indonesia Number 5 of 2014 concerning Wastewater Quality Standards, that the BOD content is 100 mg/L. The purpose of this study was to determine the difference in the effect of Moringa Oleifera seed powder dosage on reducing levels of BOD in wastewater in the Chicken Slaughterhouse industry in 2021. The method in this study was a Quasi-experimental with a Pre-Test-Post-Test Group research design. In the normality test, the data were normally distributed, then based on the One Way ANOVA test, the significant value that obtained was 0,000 0.05, which means that H0 is rejected and Ha is accepted, which means that there is a difference in the effect of the dose of Moringa oleifera seed powder on reducing levels of Biochemical Oxygen Demand in wastewater of Chicken Slaughterhouse industry in 2021. BOD levels and met the quality standard, namely the dose of 1 g/L with a result of 93.44 mg/L which decreased by 88.53%.

Comparison of pollutants in stormwater runoff from asphalt and concrete roads

Controlling non-point source pollutants (NPSPs) is critical in achieving good surface water quality; the contribution of road runoff has recently received increased attention. This study monitored the runoff characteristics of NPSPs, including suspended solids, particle size distribution, heavy metals, organic matter, and nutrients, from asphalt and concrete roads. Water quality parameters, including biochemical oxygen demand (BOD), chemical oxygen demand (COD), and nutrients of the receiving reservoir, were also investigated. During the first flush, the changes in pollutant concentrations over time were higher on concrete roads than asphalt roads. Concentrations peaked over a short period, while an increased pollutant concentration may be present several days after rain. The runoff concentration and particle size distribution were higher on concrete roads, whereas the concentrations of heavy metals were similar in asphalt and concrete roads. The organic matter concentration of asphalt roads was higher, or identical, to that in the first flush from concrete roads; this may be associated with the road location. Water quality analysis of the reservoir showed relatively good results for BOD, COD, and nutrient concentrations. Road construction was a factor that determined the characteristics of NPSPs in road runoff.

Assessment on biochemical oxygen demand (BOD) removal using treatment train system for agricultural run-off

Agricultural runoff is non-point source pollution that is unpredictable and difficult to control. Best Management Practices (BMPs) and Low Impact Development (LID) has been utilized as a method to manage agricultural runoff. Treatment train systems are LID-BMPs arranged in a series that aims to treat and manage agricultural runoff. This study focuses on the use of treatment train systems to reduce the concentration of BOD in agricultural runoff. A treatment train system was set up with three varying configurations to evaluate the efficiency of BOD removal. The three configurations consisted of no vegetation set which acts as the control, vegetated set, and vegetated set with the saturated zone. All three configurations showed good final removal rates of BOD at 56% for the control and 75% and 85% for both vegetated sets without and with the saturated zone. The control is classified classifying it as Class III according to Water Quality Standards, while both vegetated set without and with saturated zone had classified both sets as Class II and I, respectively. The performance of the treatment train system was compared to the use of a single bioretention system.

Impact of Global Warming on Dissolved Oxygen and BOD Assimilative Capacity of the World’s Rivers: Modeling Analysis

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody’s dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world’s natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former’s higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or “critical” DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification.

Control of activated sludge treatment process using pre-compensated multi-variable quantitative feedback theory-based controller

This paper deals with the design of a pre-compensated multi-variable quantitative feedback theory (QFT)-based fully populated matrix controller for an activated sludge treatment process (ASTP) of a waste water treatment plant (WWTP). The regulation of the concentration of biochemical oxygen demand ([Formula: see text]) and ammonium-ion ([Formula: see text]) is the control objective. The plant dynamics are obtained using physical laws available in the literature. The parametric uncertainty is quantified from the measurement data obtained from a real ASTP of an oil refinery. The model is duly cross-validated. A novel technique is proposed to design a pre-compensator that will enhance the diagonal dominance of the plant transfer function matrix. A diagonal controller and a pre-filter, are then designed using a sequential multi-input multi-output (MIMO) QFT-based methodology to meet a set of performance specifications such as relative stability, disturbance rejection, robust tracking and so forth. The simulation results validate the effectiveness of the proposed control scheme. A comparative analysis with reported works shows that the proposed control scheme outperforms some of the reported control strategies.

Co-optimization of wastewater treatment plants interconnected with smart grids

Wastewater treatment plants (WWTPs) and smart grids of urban systems are in a strong nexus. Energy consumption of WWTPs will directly impact the economy of the smart grids, while the energy forecast, marketing, and resource allocation of smart grids will affect the economy of WWTPs. As such, these two critical infrastructures need to be operated and managed cooperatively to maximize the mutual economic benefits. In this paper, a mixed integer nonlinear programming (MINLP) co-optimization model is developed to address the day-ahead economic dispatch problem of smart grids embedded with interdependent links among wastewater treatment plants and smart grids. The energy demand of WWTPs is optimized by minimizing the energy consumption of the aeration module, mixed liquor pumping, primary clarifier’s influent pumping, secondary clarifier’s sludge pumping, and mixing devices that are integrated in the dynamic economic dispatch problem of smart grid. Additionally, biochemical oxygen demand (BOD) and total Kjedhal nitrogen (TKN) concentrations of the treated wastewater is also incorporated in the economic dispatch problem to ensure of the high quality of the WWTP’s effluent. Electricity consumption of the buildings is also added as a constraint to the economic dispatch, serving as a dynamic load for smart grid. Case studies are conducted to examine the impact of wastewater flow rate, influent BOD and TKN concentrations, battery efficiency, and end-of-day battery’s state of the charge constraints on economic dispatch of the smart grid. The results show that total operational cost and energy consumption of the integrated WWTP-smart grid is increased only by 3.4% and 1.75%, respectively, as the daily influent flow rate and BOD & TKN concentrations are increased from their minimum to maximum thresholds.

Chemical attributes of percolate from degraded sand soil irrigated with treated industrial wastewater

AbstractApplying treated industrial tannery wastewater to soil can be an important practice for its disposal and aid in the recovery of degraded soils. This study aimed to evaluate the chemical attributes of the percolate of degraded soil irrigated with treated industrial wastewater (TIW). The experiment was carried out in a greenhouse, using soil‐filled polyvinyl chloride columns. The treatments consisted of TIW at increasing rates (0%, 25%, 50%, 75%, and 100%) and organomineral and organic fertilization. Irrigation with treated wastewater on soil degraded by clay extraction increased mineral nitrogen, biochemical oxygen demand (BOD), electrical conductivity, sodium, and sodium adsorption ratio in percolate under maize cultivation. Irrigation with TIW increased mineral nitrogen and BOD in the percolate by 34% and 25%, respectively, relative to the control treatment (plain water). Concentrations of total nitrogen and BOD must be less than 100 and 65 mg L–1, respectively, to minimize the potential contamination of water bodies. The degraded soil and maize (Zea mays L.) cultivation reduced the total mineral nitrogen and BOD in the percolate by 96% and 84%, respectively. The sodium adsorption ratio had a high removal efficiency of 79% of the percolate when compared to TIW.

A kinetic approach to the formation of two-mediator systems for developing microbial biosensors as exemplified by a rapid biochemical oxygen demand assay.

This work proposes a method of forming a microorganism-mediator(s) receptor system, in which the rates of separate stages of mediator bioelectrocatalysis are used as the basis for the development of biosensors for the biochemical oxygen demand (BOD) rapid assay. In the presence of a ferrocene mediator, the yeast Blastobotrys adeninivorans was shown to enable oxidation of a larger range of substrates as compared with other investigated microorganisms-bacteria Escherichia coli and yeast Ogataea polymorpha. The rate constants of the interaction of the yeast B. adeninivorans with nine compounds, electron transfer mediators, were determined; the best mediator for these microorganisms was found to be neutral red (k int = 0.681 ± 0.009dm3/gs). Neutral red possesses a high rate of interaction with the ferrocene mediator (14,200 ± 100dm3/mols) shown earlier to be the most promising acceptor of electrons at a carbon paste electrode (0.4 ± 0.1cm/s). These features enabled the formation of a two-mediator ferrocene-neutral red system to be used in a biosensor. A two-mediator-based biosensor had a higher sensitivity (the lower limit of detected BOD concentrations, 0.16mg/dm3) than that of a one-mediator system based on neutral red and ferrocene. Analysis of ten samples from surface water reservoirs showed the combination of ferrocene, neutral red and the yeast B. adeninivorans to enable the data that highly correlated (R = 0.9693) with those of the standard method.

Utilising hen feather as an adsorbent on comparison with bentonite in distillery effluent using Fourier-transform infrared spectroscopy and thermogravimetric analyser

ABSTRACT Distillery effluent is a dark-coloured recalcitrant organic formed as a result of mailard’s reaction during fermentation of molasses. The high strength effluent is highly complicated to dispose due to its properties, such as acidic nature, low pH, high total solids concentration, high concentration of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). The disposal of effluent from the distilleries is attempted using hen feather as an organic adsorbent which is a biodegradable waste, and is compared with the bentonite as an inorganic adsorbent. The adsorption experiments were conducted in the real-time distillery effluent using hen feather and bentonite for a concentration range of 1000 to 3000 ppm. The effect of different adsorbents was studied using Fourier-transform infrared spectroscopy and Thermogravimetric analyser. The gravimetric analysis of the hen feather and bentonite after adsorption indicates the 72% and 49.96% of total dissolved solids could be removed, respectively. The TGA results showed that the residue obtained by distillery effluent solids in oxygen mode was 30% which is reduced to 9% for hen feather adsorbed distillery solid samples. From the experiments, the results show that the residue from the distillery effluent solids was reduced to 9% on comparing with the bentonite 40%. The amide group in the hen feather adsorbs higher as the distillery effluent is the product of sugar and amine fermentation. Hence, the hen feather is the better option to use for the adsorption and to reduce the solid waste.

Coconut shell-based activated carbon preparation and its adsorption efficacy in reducing BOD from The Real Wastewater from Kitchen Restaurant (RWKR): Characteristics, Sorption Capacity, and Isotherm Model

Real Wastewater from Kitchen Restaurant (RWKR) contains high concentrations of Biochemical Oxygen Demand (BOD) pollutants to pollute the environment. One of the processing alternatives to reduce BOD is the adsorption method using activated carbon from coconut shells. This study aims to determine coconut shell-activated carbon as an adsorbent for the adsorption of organic matter to reduce BOD in RWKR. The method begins with making adsorbents that are activated with activators on HCl 3 M, NaOH 3 M, and H3PO4 M, then a preliminary adsorption test is carried out to select the best activator on coconut shell activated carbon to reduce BOD in RWKR. Determining the optimum conditions for adsorption was carried out by varying pH 3, 4, 5, 6, 7, and 8. Variation of contact time with a stirring speed of 250 rpm, then determined the isotherm model. The remaining organic matter in the wastewater will be measured using a DO meter based on SNI 6989.72: 2009 concerning the method of testing for biochemical oxygen demand (BOD). The results showed that the appropriate activator for coconut shell activated carbon was H3PO4 3 M with an average percentage value of uptake of 89.690%. The adsorption process's optimum pH is at pH 3 with an absorption percentage value of 88.626%. The optimum contact time is at 10 minutes and the adsorption isotherm model used is the Freundlich isotherm with a regression value of R2 = 0.8864.

Treatment of wastewater from a dairy plant by adsorption using synthesized copper oxide nanoparticles: kinetics and isotherms modeling optimization

Dairy plants produce 1 to 4 L of wastewater per 1 L of processed milk. The wastewater contains high values of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations, in addition to high levels of dissolved solids. In this study, synthesized copper oxide nanoparticles (CuONPs) coupled with Sophora Japonica fruit, were used as an adsorbent, for the first time, to treat the effluent of dairy plants in a batch adsorption process. The analysis techniques, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the adsorbent. The COD removal, using (CuONPs)-based adsorbent, was investigated by varying contact time, masses of the adsorbent, initial COD value and temperatures. The optimum conditions for highest removal percentage were contact time of 120 min, a temperature of 25 °C, pH value of 7.5, and 1 g of adsorbent. The initial COD values used were in the range of 100-700 ppm. The COD percent removal was in the range of 77 to 95%. Freundlich isotherm exhibited the best fitting for the results (R2 = 0.998) with a favorable spontaneous exothermic adsorption process. Based on the calculated normalized deviation value, the modified diffusion model, intra-diffusion, and pseudo-second-order kinetics all showed very good fitting for the adsorption data as indicated by the kinetics study.

Impact of Suspended Solids and Organic Matter on Chlorine and UV Disinfection Efficiency of Greywater

Reusing greywater (GW) can lower domestic water consumption. However, the GW must be treated and disinfected for securing user health. This research studied at the laboratory scale, and in flow-through setups, which are generally used in full-scale GW treatment the disinfection efficiency of the two commonly used technologies (a) chlorination and (b) low-pressure UV irradiation. The disinfection methods were studied under a commonly found range of total suspended solids (TSS; 3.9–233 mg/L) and 5-d biochemical oxygen demand (BOD5) concentrations (0–107 mg/L) as a representative/proxy of bioavailable organic matter. The negative effect of TSS began even at low concentrations (&lt;20 mg/L) and increased consistently with increasing TSS concentrations across all the concentrations tested. On the other hand, the negative effect of BOD5 on FC inactivation was observed only when its concentration was higher than 50 mg/L. Multiple linear regression models were developed following the laboratory results, establishing a correlation between FC inactivation by either chlorination or UV irradiation and initial FC, TSS, and BOD5 concentrations. The models were validated against the results from the flow-through reactors and explained the majority of the variability in the measured FC inactivation. Conversion factors between the laboratory scales and the flow-through reactor experiments were established. These enable the prediction of the required residual chlorine concentration or the UV dose needed for an on-site flow-through reactor. This approach is valuable from both operational and research perspectives.

Optimisation of an original CO2-Enhanced natural treatment system for reclaiming and reusing anaerobically digested strong wastewater from animal breeding industry

Strong wastewater from the animal breeding industry threatens the environmental and human health, while the widely used anaerobic digestion treatment is insufficient. To achieve the reclamation and reuse of the effluent containing an excessively high amount of nutrients (N, P and K) and a certain extent of biochemical oxygen demand (BOD), an original CO 2 -enhanced natural treatment system was put forward, which was composed of trickling filter and soil-plant units installed inside an elaborate greenhouse with an elevated CO 2 concentration. On the basis of previous feasibility studies , an investigation on the system’s limitations and potential were carried out for further optimisation , in which red ball earth-Kentucky bluegrass column tests were conducted at the recommended CO 2 concentration of 1,400 ppm for two specific scenarios, i.e. high BOD concentration and increasing hydraulic and nutrient loading rates. N is the most critical factor determining the effect and efficiency of the system, and results confirmed that, to establish a satisfactory nitrification function in the soil for N removal, adequate BOD reduction prior to land application was indispensable. Optimal operational strategies and parameters, as well as design information for scale-up, are also discussed. By means of nutrient balance approximation, the system’s significant capabilities of removing and recovering waterborne nutrients are further presented, specifically complete removal of both N and P, and 8%, 18% and 18% recovery rates for N, P and K, respectively. Meanwhile, carbon balance analysis reveals its potential for substantially reducing greenhouse gas emission , as 9% of the input waterborne C is sequestrated for establishing plant biomass and maintaining greenhouse CO 2 concentration at the designated level. More importantly, the above are realised in a highly profitable manner, as the value of the high-quality turf product can be an order of magnitude higher than the cost for system operation and maintenance. This original system provides an innovative way for rural communities worldwide to achieve sustainable development via wastewater reclamation and reuse. • An innovative CO 2 -enhanced natural treatment system was proposed and developed. • Ensuring sound nitrification in the soil for N removal was the most critical issue. • Significant nutrient removal and recovery and CO 2 emission reduction were achieved. • Optimal operating conditions and design information for scale-up are discussed. • The profitable system is applicable to reclamation and reuse of strong wastewater.

Particulate and Dissolved Organic Matter in Stormwater Runoff Influences Oxygen Demand in Urbanized Headwater Catchments.

Increasing inputs of organic matter (OM) are driving declining dissolved oxygen (DO) concentrations in coastal ecosystems worldwide. The quantity, source, and composition of OM transported to coastal ecosystems via stormwater runoff have been altered by land use changes associated with urbanization and subsequent hydrologic flows that accompany urban stormwater management. To elucidate the role of stormwater in the decline of coastal DO, rain event sampling of biochemical oxygen demand (BOD) in samples collected from the outfall of stormwater ponds and wetlands, as well as samples of largely untreated runoff carried by stormwater ditches, was conducted across a range of urban and suburban development densities. Sampling also included measurements of particulate and dissolved carbon and nitrogen, carbon and nitrogen stable isotopes, and chlorophyll-a. Results suggest stormwater may be a significant source of labile OM to receiving waters, especially during the first flush of runoff, even though BOD concentrations vary both among and within sites in response to rain events. BOD variability was best predicted by particulate OM (POM) and chlorophyll-a, rather than the larger pool of dissolved OM. These findings demonstrate the importance of managing episodic stormwater discharge, especially POM, from urbanized areas to mitigate DO impairment in larger downstream systems.

Application of WASP model to simulate water pollution control of Duriangkang Dam

AbstractLocated in Batam City, Duriangkang Dam plays an essential role in providing clean water in the area, also being the first and largest estuary dam in Indonesia. However, with a total effective water volume of 107,000,000 m3, Duriangkang Dam is now heavily polluted because of enormous wastewater loads from both domestic and industrial sources that are directly discharged into the dam. The practice of fish farming has also contributed to its demise. Based on water samples collected during 2016 to 2018, the water condition for Duriangkang Dam is no longer classified as the 2nd class of raw water, based on Indonesian water standards. The present study utilizes the WASP model to evaluate and simulate possible solutions for controlling the Duriangkang Dam water pollution rate. The water quality indicators of dissolved oxygen (DO), total phosphorus (TP) and biochemical oxygen demand (BOD) concentrations are modelled. The calibration and verification results indicate the model exhibited an excellent fitting for DO, BOD and TP concentrations. Under several scenarios, it was determined that the best way to control the pollution rate within the dam is by implementing scenario 8, which include total control of the fish farms and domestic wastewater loads.