Reclamation of Municipal Wastewater

1989 ◽  
Vol 21 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Fatma A. El-Gohary ◽  
Sohair I. Abo-Elela ◽  
H. M. El-Kamah
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Complete Removal ◽  
Advanced Treatment ◽  
Chemical Coagulation ◽  
Second Stage ◽  
Treated Effluent ◽  
Stage Scheme ◽  
Nitrification Process ◽  
Nitrogen Ratio

The feasibility of applying direct advanced treatment to municipal wastewater has been investigated. A. two-stage scheme was implemented. The first stage was direct chemical coagulation of primary effluent using different coagulants to remove suspended solids and reduce the carbon to nitrogen ratio to a range suitable for nitrification. The second stage was biological sand-bed to oxidize ammonia to nitrate. The pilot plant was designed to treat 6m3/day. The results obtained showed that chemical coagulation using ferric chloride gave high quality effluent suitable for agricultural purposes. Nitrification of the 2 chemically treated effluent using sand-bed at an overflow rate of 1.358 m3/m2/d completely eliminated ammonia. Almost complete removal of suspended solids was achieved. Residual COD and BOD values were 45 mg/l and 15,5 mg/l, respectively. Fish biotoxicity was completely eliminated after nitrification process.

scholarly journals Membrane integrated process for advanced treatment of high strength Opium Alkaloid wastewaters

2018 ◽  
Vol 77 (7) ◽  
pp. 1899-1908 ◽  
Author(s):  
Güçlü Insel ◽  
Ahmet Karagunduz ◽  
Murat Aksel ◽  
Emine Cokgor ◽  
Gokce Kor-Bicakci ◽  
...  
Keyword(s):  
Inorganic Nitrogen ◽  
Oxygen Demand ◽  
High Strength ◽  
Complete Removal ◽  
Advanced Treatment ◽  
Treated Effluent ◽  
Aeration System ◽  
Total Inorganic Nitrogen ◽  
Conductivity Parameter ◽  
Activated Sludge Systems

Abstract In this study, an integrated aerobic membrane bioreactor (MBR)-nanofiltration (NF) system has been applied for advanced treatment of Opium processing wastewaters to comply with strict discharge limits. Aerobic MBR treatment was successfully applied to high strength industrial wastewater. In aerobic MBR treatment, a non-fouling unique slot aeration system was designed using computational fluid dynamics techniques. The MBR was used to separate treated effluent from dispersed and non-settleable biomass. Respirometric modeling using MBR sludge indicated that the biomass exhibited similar kinetic parameters to that of municipal activated sludge systems. Aerobic MBR/NF treatment reduced chemical oxygen demand (COD) from 32,000 down to 2,500 and 130 mg/L, respectively. The MBR system provided complete removal of total inorganic nitrogen; however, nearly 50 mgN/L organic nitrogen remained in the permeate. Post NF treatment after MBR permeate reduced nitrogen below 20 mgN/L, providing nearly total color removal. In addition, a 90% removal in the conductivity parameter was reached with an integrated MBR/NF system. Finally, post NF application to MBR permeate was found not to be practical at higher pH due to low flux (3–4 L/m2/hour) with low recovery rates (30–40%). As the permeate pH lowered to 5.5, 75% of NF recovery was achieved at a flux of 15 L/m2/hour.

scholarly journals Performance of constructed wetlands with different substrates for the treated effluent from municipal sewage plants

2019 ◽  
Vol 9 (4) ◽  
pp. 452-462 ◽  
Author(s):  
Cao Shiwei ◽  
Jing Zhaoqian ◽  
Yuan Peng ◽  
Wang Yue ◽  
Wang Yin
Keyword(s):  
Constructed Wetlands ◽  
Municipal Wastewater ◽  
Treatment Process ◽  
Loading Rate ◽  
Municipal Sewage ◽  
Advanced Treatment ◽  
Plastic Ring ◽  
Treated Effluent ◽  
Proper Operation ◽  
Conducive Environment

Abstract Constructed wetlands (CWs) are effective as an advanced treatment process for the treated effluent of municipal wastewater plants. An appropriate substrate, suitable macrophytes, and proper operation are crucial for pollutant abatement. In this research, three subsurface flow CWs with various substrates were investigated. Pollutants abatement efficiency under various operational schemes were analyzed. The results showed that the satisfactory hydraulic loading rate was 0.25 m3/(m2·d). When the C/N ratio of influent was adjusted to 5.87 by adding a carbon source, the denitrification and dephosphorization efficiency would be improved, with 7–8 mg/L for total nitrogen (TN) and 0.4 mg/L for total phosphorus (TP) in the effluent, which can achieve the Class 1A Discharge Standard for discharge to natural waterways in China. A greater depth of submersion for the substrate layer resulted in a more conducive environment for the abatement of nitrogen substances. However, a 40-cm depth of submersion in CWs results in better removal efficiency of TN and TP. A plastic ring substrate (PRS) contains biological enzyme promoter formula, which was conducive to nitrifying and denitrifying bacteria. The biofilm affinity and coordination with plants made the PRS more effective than the other two substrates, especially for NO3–-N and TN abatement efficiency.

scholarly journals Comparative evaluation of the coagulation methods effectiveness in the extraction of biologically active components from highly concentrated effluents

2020 ◽  
Vol 82 (1) ◽  
pp. 213-218
Author(s):  
V. I. Korchagin ◽  
J. N. Dochkina ◽  
E. A. Denisova ◽  
A. A. Plyakina
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Raw Materials ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Biologically Active ◽  
Active Components ◽  
Chemical Coagulation ◽  
Treated Effluent ◽  
Physico Chemical

A characteristic feature of highly concentrated effluents is the presence of valuable components - biologically active substances, which are secondary raw materials. The effectiveness of physico-chemical coagulation and electrocoagulation methods in relation to highly concentrated wastewater from a poultry processing enterprise, as well as the prevention of the secondary pollution of the effluent supplied to biological treatment, were analyzed in the work. The objects of the study included poultry stock (suspended solids 1770.0 mg / dm3, dry residue 1920.0 mg / dm3, chemical oxygen demand (COD) 1769.0 mg O2 / dm3), iron (III) FeCl3 chloride, iron soluble electrodes as the coagulant. The objectives of study involved determination of wastewater treatment effectiveness by the studied methods (physico-chemical coagulation and electrocoagulation) with the priority indicators changing: suspended solids, dry residue, chemical consumption of oxygen, iron, chlorides, and the precipitated residue mass. As a result of testing of highly concentrated effluents with a COD index of at least 1700.0 mg O2 / dm3, it was found out that during physico-chemical coagulation with FeCl3 at a concentration of 0.75 g / dm3, the content of priority indicators decreased by no less than 60%, while the effectiveness of electrocoagulation in relation to reducing the concentration of priority indicators was at least 70%. The content of iron compounds in wastewater with the application of electrochemical coagulation was 2.08 mg / dm3, which is 34% lower than after treatment of the effluent with iron (III) chloride FeCl3 at a concentration of 0.75 g / dm3. The chloride concentration did not change. As a result of the treatment of the effluent during the coagulation of (III) FeCl3, the secondary contamination of the treated effluent and the isolated products with iron and chlorides took place. This aspect may adversely affect the subsequent biological wastewater treatment, as well as lead to a decrease in the quality of the isolated product and its use limitation. Electrocoagulation is a more preferred way of isolating valuable components in relation to physico-chemical coagulation.

Wastewater Treatment by Artificial Wetlands

1985 ◽  
Vol 17 (4-5) ◽  
pp. 443-450 ◽  
Author(s):  
R. M. Gersberg ◽  
B. V. Elkins ◽  
C. R. Goldman
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Inorganic Nitrogen ◽  
Application Rate ◽  
Secondary Treatment ◽  
Artificial Wetlands ◽  
Treated Effluent ◽  
The Mean ◽  
Removal Efficiencies ◽  
Solids Removal

This report describes studies of artificial wetlands at Santee, California which demonstrate the capacity of these systems for integrated secondary treatment (BOD and suspended solids removal) and advanced treatment (nitrogen removal) of municipal wastewater effluents. When receiving a blend of primary (1°) and secondary (2°) wastewaters at a blend ratio of 1:2 (6 cm per day 1° : 12 cm per day 2° ), mean removal efficiencies for a complete year of operation from July, 1982 through July, 1983 were 80% for total nitrogen (TN) and 80% for total inorganic nitrogen, with the mean inflow TN level of 21.5 mgl−1 reduced to a mean value of 4.3 mgl−1 in the wetland effluent. The BOD and suspended solids removal efficiencies were 93% and 88% respectively. The mean wetland effluent values for both BOD and suspended solids were below the 10/10 mgl−1 standard for advanced secondary treatment. When primary effluent was the sole source of inflow to the artificial wetlands, BOD and suspended solids levels approaching the quality of a secondary treated effluent (30/30 mgl−1) could be attained at an application rate of 6-8.3 cm per day. In this case, mean BOD and suspended solids removal efficiencies for the complete year from July, 1982 through August, 1983, were 78% and 80% respectively, with the effluent levels reduced to mean values of 33 mgl−1 for BOD and 10 mgl−1 for suspended solids. At the application rate of 6 cm per day, our study shows that only 16 acres (6.5 ha) of constructed wetlands would be required to treat 3785 m3 of primary wastewaters to secondary treatment levels. Data on capital and O&M cost show that artificial wetlands are competitive with other treatment technologies available to small to medium sized communities.

Comparative Studies on the Primary Treatment of Municipal Wastewater for Ocean Disposal

1993 ◽  
Vol 28 (7) ◽  
pp. 1-7 ◽  
Author(s):  
Chiu-Yang Chen
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Primary Treatment ◽  
Aeration Rate ◽  
Aluminium Chloride ◽  
Chemical Coagulation ◽  
Treatment Processes ◽  
Organic Removal ◽  
Filter Papers ◽  
Sedimentation Processes

The objective of this study is to evaluate the effectiveness of primary treatment on municipal wastewater before it is discharged into the ocean. A series of filter papers of specified pore size was applied to measure the removal of organics and solids in wastewater through various primary treatment processes. For plain sedimentation, the removal of suspended solids was always less than 50% while COD and BOD removals were 23-41% and 15-27%, respectively. For chemical coagulation with the addition of poly aluminium chloride (PAC), 70% SS removal was obtained with a PAC dose of 30 mg/l. If polyelectrolyte is added (about 1 mg/l), the dosage of PAC can be reduced to around 10 mg/l to maintain the SS removal efficiency at the same level. For air flocculation treatment by preaeration followed by sedimentation, the most achievable removal of solids from wastewater of more than 80% was obtained at an aeration rate of 0.5-1.0 Nl air/l. In particular it is more effective for smaller solids than for larger solids in wastewater. On organic removal, about 15-40% removal in terms of COD or BOD was obtained by treating wastewater with either plain sedimentation or air flocculation and sedimentation processes. The efficiency of organic removal from wastewater increased to about 60% by utilizing chemical coagulation and sedimentation treatment. Based upon the characteristics of tested municipal wastewater, in order to maintain the SS removal at 65% or above as regulated, the treatment processes of chemical coagulation or air flocculation followed by sedimentation should be employed.

Study on the performance of an up-flow aerated biofilter (UAB) in municipal wastewater treatments

1994 ◽  
Vol 30 (11) ◽  
pp. 25-33 ◽  
Author(s):  
Yoshimasa Watanabe ◽  
Satoshi Okabe ◽  
Tomochika Arata ◽  
Yuji Haruta
Keyword(s):  
Organic Matter ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Unique Feature ◽  
Aeration Rate ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Running Cost ◽  
And Performance ◽  
Activated Sludge Systems

A comprehensive wastewater treatment system that accomplishes oxidation of organic matter, nitrification, and denitrification was developed, and its characteristics and performance were investigated. A municipal wastewater was treated by an up-flow aerated biofilter (UAB), in which biofilms were developed on stainless meshes installed horizontally. This UAB exhibited a great potential ability of oxidation of organic matter, SS stabilization, and nitrification due to a unique aeration mechanism giving high DO concentrations with relatively low aeration rates. Another unique feature of the UAB was that attached biofilms on stainless meshes physically filtered out and/or adsorbed suspended solids in the wastewater in addition to the biological oxidation of organic matter. A stable nitrification could be achieved at HRT=10 hours corresponding to a hydraulic loading of 86 L m−2 d−1 and at a ratio of aeration rate to wastewater flow rate (A/W) of 2, which is considerably low as compared to aeration rates of typical activated sludge systems. This UAB system also could handle relatively high hydraulic loading rates. The UAB used in this study still have enough space to install more stainless meshes so as to reduce hydraulic loading rates resulting in the reduction of HRT and aeration rate, which leads to improvement of the system performance as well as reduction of the running cost.

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

Activated sludge plant facing grape harvest period – a case study

1996 ◽  
Vol 34 (11) ◽  
pp. 25-32 ◽  
Author(s):  
P. Chudoba ◽  
R. Pujol
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Organic Pollution ◽  
Worst Case ◽  
Wine Production ◽  
Original Solution ◽  
Treated Effluent ◽  
Nominal Capacity ◽  
Sludge Settleability

Most of municipal activated sludge plants located in wine production regions receive winery wastewaters during the grape harvest period which lasts usually only a few weeks. A drastic increase in organic pollution (COD, BOD) during this period generates a temporary overloading, resulting very often in biological problems such as decreased sludge settleability, sludge floc disintegration, increased SS concentration in treated effluent and in the worst case a complete plant failure. In order to work satisfactorily even during those temporary overloading periods, the plant has to be oversized. This strategy is rather costly, because such a plant has to run below its nominal capacity during a major part of the year. An original solution has been proposed and successfully tested at a municipal wastewater treatment plant in Eguisheim, France. The proposed technique is based on the addition of a mineral material with a low particle size, whose presence positively influences the physical behaviour of the sludge and will allow the nominal capacity of the plant to be surpassed without any important modification. The modification of the sludge structure around the added powdered material improved significantly the sludge settleability (DSVI< 160 ml/g) and enabled the plant to treat organic pollution several times higher than the nominal level.

Municipal wastewater treatment with pond–constructed wetland system: a case study

2005 ◽  
Vol 51 (12) ◽  
pp. 325-329 ◽  
Author(s):  
X. Wang ◽  
X. Bai ◽  
J. Qiu ◽  
B. Wang
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Oxidation Pond ◽  
System A ◽  
Treated Effluent ◽  
Wetland System ◽  
Oxidation Ponds ◽  
Better Than

The performance of a pond–constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond–constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

Advanced Treatment of Coking Wastewater by Oxidation Process Using Pyrite and Hydrogen Peroxide

2013 ◽  
Vol 726-731 ◽  
pp. 2521-2525
Author(s):  
Zhi Yong Zhang ◽  
De Li Wu
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidation Process ◽  
Low Cost ◽  
Oxygen Demand ◽  
Utilization Efficiency ◽  
Advanced Treatment ◽  
Coking Wastewater ◽  
Second Stage ◽  
Potential Alternative ◽  
High Utilization

Coking wastewater is a kind of recalcitrant wastewater including complicate compositions. Advanced treatment of coking wastewater by Fenton-Like reaction using pyrite as catalyst was investigated in this paper. The results show that the chemical oxygen demand (COD) of coking wastewater decreased significantly by method of coagulation combined with two-stage oxidation reaction. COD of wastewater can decrease from 250mg/l to 45mg/l after treatment, when 2g/L pyrite was used in each stage oxidation and the dosage of hydrogen peroxide (H2O2) is 0.2ml/l for first stage treatment, 0.1ml/l for second stage treatment respectively. The pyrite is effective to promote Fenton-Like reaction with low cost due to high utilization efficiency of H2O2, moreover, catalyst could be easily recovered and reused. The Fenton-Like reaction might be used as a potential alternative to advanced treatment of recalcitrant wastewater.

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