Modelling the performance of anaerobic wastewater stabilization ponds

1995 ◽  
Vol 31 (12) ◽  
pp. 171-183 ◽  
Author(s):  
M. M. Saqqar ◽  
M. B. Pescod

The performance of the primary anaerobic pond at the Alsamra Wastewater Treatment Plant in Jordan was monitored over 48 months. Overall averages for the removal efficiencies of BOD5, COD and suspended solids were 53%, 53% and 74%, respectively. An improvement in removal efficiency with increase in pond water temperature was demonstrated. A model, which takes into account the variability of raw wastewater at different locations, has been developed to describe the performance of a primary anaerobic pond in terms of a settleability ratio for the raw wastewater. The model has been verified by illustrating the high correlation between actual and predicted pond performance.

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Chu-I Cheng ◽  
Yu Mei Chao ◽  
Ming-Chuan Lin ◽  
Chiung-Hsun Lin

Coking wastewater contains toxic compounds such as ammonia, phenolics, cyanides, thiocyanate, and thiosulfate. In normal situation, these compounds can be 100% decomposed by activated sludge in the wastewater treatment plant. However, a new factor, high water temperature, caused by the covering of the basins, has been found to reduce the removal rate of the pollutants, especially the thiocyanate. Several remediation measures were applied to improve the biological process performance. A series of batch and continuous-flow biodegradation tests have demonstrated that the relatively low temperature ranging from 20 to 37°C attained perfect removal efficiency (∼100%) of SCN− from the coke plant wastewater. When the temperature is increased to 38, 39°C, the SCN− removal rate decreased to 30 ∼ 50% after 48 hours of temperature shift. Moreover, when the temperature is increased to 40 to 45°C, SCN− biodegradation is significantly decayed one day after the temperature shock, and the SCN− removal efficiency dropped gradually to 0%, with microbial deterioration during day 1 to day 4. Meanwhile, the COD removal has also decreased from 85% down to 45% at 45°C. Both laboratory verifications confirmed that 40°C should be the critical water temperature for the SCN− degrading microbe to function well in the activated sludge process. In order to stabilize the pollutant removing ability of the procedure, the water temperature of aeration basin is set to operate under 37°C. Four modifications were practiced on site to decrease the temperature of activated sludge. Only the last alternative measure worked well with the opened hand hole, 50% of total cover area, to discharge the water vapor and gas emission from the head space of aeration basin. The water temperature has dropped from 41 to 36°C in the early summer of June with ambient temperature of 37°C, suggesting that partially uncovering the basin does help maintain the water temperature. Finally, we suggest some measures that can be applied to establish a standard process on site in order to ensure that the aeration basin temperature stays under 37°C and that our biotreatment system can maintain its function in the future.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2004 ◽  
Author(s):  
Al-Mashaqbeh ◽  
Alsafadi ◽  
Dalahmeh ◽  
Bartelt-Hunt ◽  
Snow

The largest wastewater treatment plant in Jordan was monitored in the summer to determine the removal of pharmaceuticals and personal care products (PPCPs). Grab samples were collected from the influent and effluent of As-Samra Wastewater Treatment Plant (WWTP). Liquid chromatography and tandem mass spectrometry (LC–MS/MS) were utilized to determine the concentrations of 18 compounds of pharmaceuticals and personal care products (PPCPs). The results showed that 14 compounds were detected in the collected samples from the influent and effluent of As-Samra WWTP. These compounds are 1,7-dimethylxanthine, amphetamine, acetaminophen, caffeine, carbamazepine, cimetidine, cotinine, diphenhydramine, methylenedioxymethamphetamine (MDMA), morphine, phenazone, sulfamethazine, sulfamethoxazole, thiabendazole, and trimethoprim. However, four compounds were below the detection limit (<0.005 µg/L), namely cimetidine, methylenedioxyamphetamine (MDA), methamphetamine, and sulfachloropyridazine. Among PPCPs, the highest estimated average concentrations in raw wastewater were caffeine, acetaminophen, 1,7-dimethylxanthine, cotinine, and carbamazepine sampled during the summer, at an estimated concentration of 155.6 µg/L, 36.7 µg/L, 10.49 µg/L, and 1.104 µg/L, respectively. However, the highest estimated average concentrations in treated wastewater were for carbamazepine, sulfamethoxazole, caffeine, cotinine, and acetaminophen, at 0.856 µg/L, 0.096 µg/L, 0.086 µg/L, 0.078 µg/L, and 0.041 µg/L, respectively. In general, the results showed that some compounds in the collected samples of wastewater in Jordan have concentrations exceeding the values reported in the literature. The removal efficiency rates of 1,7-dimethylxanthine, acetaminophen, caffeine, cotinine, morphine, and trimethoprim were higher than 95%, while those of carbamazepine, sulfamethazine, and sulfamethoxazole were lower than 22.5%. Moreover, diphenhydramine and thiabendazole had negative removal efficiency rates. The removal efficiency rates of the PPCPs in As-Samra WWTP were generally consistent with those of indicator compounds reported in the literature for conventional WWTPs.


2001 ◽  
Vol 44 (1) ◽  
pp. 113-120 ◽  
Author(s):  
G. Esposito ◽  
C. Bastianutti ◽  
G. Bortone ◽  
F. Pirozzi ◽  
S. Sgroi

The effects of suppressing primary sedimentation on nitrogen removal efficiency of a pre-denitrification system have been evaluated for a large municipal wastewater treatment plant. Simulations have been carried out using the STOAT model. For both the process schemes with and without primary sedimentation, nitrification efficiencies are calculated for increasing influent loads of COD, total N and suspended solids. The sensitivity analysis shows that for the usual carbon to nitrogen ratios in the raw influent both the process schemes allow the requested removal efficiencies, whereas for significantly high C/N ratios the scheme with primary sedimentation is preferable.


1995 ◽  
Vol 31 (12) ◽  
pp. 185-190 ◽  
Author(s):  
Muwaffaq M. Saqqar ◽  
M. B. Pescod

Sludge accumulation in the first anaerobic pond at the Alsamra Wastewater Treatment Plant in Jordan has been monitored over a period of years. Homogeneous distribution of sludge over the pond bottom has not been achieved. The maximum amount of sludge has not accumulated near the inlet. This is due to scouring of the settled materials near the pond inlet and outlet by the high jet velocity of the incoming flow. A model has been developed to describe the volume of sludge accumulated (VAS) in the primary anaerobic pond. The model has been derived on the basis of the non-biodegradable materials in the settled sludge. VAS has been described in terms of the mass rates (F) of suspended solids and total BOD5 in the raw wastewater and an accumulated sludge coefficient (KAS).


2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.


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