Performance Stability of Small Biological Chemical Treatment Plants

1990 ◽  
Vol 22 (3-4) ◽  
pp. 275-282
Author(s):  
R. Storhaug
Keyword(s):  
Activated Sludge ◽  
Chemical Treatment ◽  
Chemical Precipitation ◽  
Poor Quality ◽  
Precipitation Process ◽  
Chemical Plants ◽  
Effluent Standards ◽  
Main Portion ◽  
Rotating Biological Contactors ◽  
Number Of Treatment

Biological and chemical treatment plants constitute a main portion of the overall number of treatment plants in Norway. The biological and chemical plants are divided into three process groups, simultaneous precipitation and activated sludge, combined precipitation and rotating biological contactors (RBC) and post precipitation and activated sludge. Aluminium sulphate or ferric chloride are the commonly used flocculants in the chemical precipitation process. Effluent data from 174 Norwegian biological chemical treatment plants are evaluated. Compared to the effluent standards for each process group, post precipitation shows the best performance. On an average these plants have the lowest actual utilization of the design capacity. The most important factors that cause the treatment plants not to meet the effluent standards are, poor quality of the sewer system, improper design of the plant and organizational problems. Satisfactory separation of particles, flow equalization and proper operational management, are the basic demands to achieve low effluent concentrations for tot-P and BOD7.

Nutrient Removal in a Short Retention Time Sewage Treatment Plant

1991 ◽  
Vol 24 (10) ◽  
pp. 327-328
Author(s):  
Ingemar Karlsson
Keyword(s):  
Organic Matter ◽  
Chemical Treatment ◽  
Energy Demand ◽  
Biological Treatment ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Anaerobic Treatment ◽  
Precipitation Process

Chemical treatment of sewage water is today often considered as a method for phosphorus reduction and used in combination with biological treatment. The experience in Scandinavia, however, shows that chemical treatment alone gives beside a good phosphorus removal also a high BOD reduction. Due to the very low investment cost for such a process it has been adapted in Scandinavia as an alternative to biological treatment. Where the demand is for greater sewage treatment the most feasible method is to complement the chemical precipitation process with a compact biological treatment. In Sweden the dominating post (and also the simultaneous) precipitation process has in many plants been replaced by a chemical pre-treatment process, because with pre-precipitation most of the organic matter is coagulated and extracted already in the primary clarifier. The energy demand in the biological process will decrease. The organic matter in the sludge will increase, which in an anaerobic digester means more digester gas. The unloading pre-precipitation effect can also give advantages for nitrification. The important BOD/TKN ratio is decreased. It is possible to build up a high sludge age and to upgrade a plant without tank expansion to a nitrifying plant. Pre-precipitation is normally not influencing the readily degradable BOD, which is about 25% of the total BOD and therefore a perfect electron donor for pre-denitri-fication is still available. The pre-precipitated sludge contains 75% of the organic matter in the sewage and can by hydrolysis be converted to readily degradable organic matter, which presents a valuable carbon source for the denitrification process. The hydrolysation process can be performed by, for instance, anaerobic treatment or heat treatment. This paper will review experiences from full-scale applications as well as pilot plant and laboratory studies.

Examples for the Upgrading of Existing Activated Sludge Plants for Nutrient Removal

1990 ◽  
Vol 22 (7-8) ◽  
pp. 113-121
Author(s):  
W. Maier
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
West Germany ◽  
Sewage Treatment Plants ◽  
Effluent Standards ◽  
Near Future

In view of the new effluent standards in West Germany, including nitrification and phosphorus elimination, many of the existing sewage treatment plants will have to be rebuilt or expanded. Another demand which will have to be dealt with in the near future is denitrification. Under consideration of the large BOD5-loads which were taken into account when designing the plants, many of them nitrify during the summer or can be easily converted to operate with nitrification. Principles for planning the upgrading of such plants have been laid down in order to achieve the required effluent concentrations. The application of these principles is demonstrated with examples of upgraded plants.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

scholarly journals Efficiency of Biological Phosphorus Removal by Filamentous Bacteria

2016 ◽  
Vol 21 (1-2) ◽  
pp. 117-123 ◽  
Author(s):  
Alicja Machnicka ◽  
Klaudiusz Grübel
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Water Environment ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Heterogeneous Structure ◽  
Filamentous Bacteria ◽  
Biological Phosphorus Removal ◽  
High Concentration ◽  
Sludge Flocs

AbstractPhosphorus removal in wastewater treatment plant is carried out by chemical precipitation, advanced biological treatment or a combination of both. One of the biggest problems with high concentration of phosphorus in water environment is eutrophication. Activated sludge flocs have a heterogeneous structure, which consist of a variety of microorganisms. Filamentous bacteria are normally present in the activated sludge and have ability to assimilation of phosphorus. In this study phosphorus accumulation by isolated filamentous bacteria from activated sludge foam was present.

scholarly journals Recovery Ion Hg2+ dari Limbah Cair Industri Penambangan Emas Rakyat dengan Metode Presipitasi Sulfida dan Hidroksida

2018 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Ilma Fadlilah ◽  
Agus Prasetya ◽  
Panut Mulyono
Keyword(s):  
Gold Mining ◽  
Mercury Level ◽  
Liquid Waste ◽  
Treatment Method ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Sulphide Precipitation ◽  
Slow Mixing ◽  
Precipitation Formation

Unlicensed gold mining activities (PETI) using mercury (Hg) as a gold element binder is called the amalgamation process. Mercury is a heavy metal toxic. The use of mercury can potentially cause pollution in environment, especially the aquatic environment. For overcoming the heavy metals mercury in liquid waste, it needs an alternative wastewater treatment method called chemical precipitation. This study is aimed to recover Hg2+ ions from liquid wastes by using sulphide precipitation and hydroxide methods. This research studied the effect of pH on Hg ions which is deposited in the precipitation process and found out the rate of Hg precipitation formation. Precipitation was done by using sodium sulphide (Na2S) 0.3 M and Ca(OH)2 0.004 M as a precipitation agent with rapid mixing speed for about 200 rpm for 3 minutes and continued with slow mixing for about 40 rpm for 30 minutes. Then, just let the liquid sample be for 24 hours to precipate the precipitate formed. The results show that precipitation method by using a Na2S solution can decrease the content of Hg in HgCl2 synthetic waste. An optimum  mass of HgS precipitate of  0,0458 g was achieved pH 9 for 200 mL of wastewater liquid with a removal efficiency percentage up to 99.81%. The concentration of mercury can be derived from 130 ppm to 0.25 ppm. The rate of formation of HgS precipitate was obtained 0.0004g/ hour. While, hydroxide precipitation method can decrease mercury level up to 90,11% at pH 12 and mass of Hg (OH)2 precipitate obtained is 0,2784 g. However, the result of EDX analysis of the precipitate of Hg (OH)2 shows that the content of Hg precipitate is just 0.281%.

Implementation of EU discharge guidelines at IVAR's Regional Wastewater Treatment Plant of North Jaeren, Stavanger, Norway

2001 ◽  
Vol 44 (1) ◽  
pp. 33-39 ◽  
Author(s):  
O. Tornes
Keyword(s):  
Wastewater Treatment ◽  
Feasibility Study ◽  
Chemical Treatment ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Full Scale ◽  
Precipitation Process ◽  
European Economic Area ◽  
The Eu

Norway is a leading country on wastewater treatment comprising chemical precipitation processes. This is because Norwegian effluent standards to the North Sea have traditionally focused on phosphorus removal. In most cases, chemical treatment therefore has been considered to give lower investment and operating costs than biological treatment. Norwegian wastewater policy and management is based on the EU guidelines resulting from the EEA (European Economic Area) Agreement. According to the 1991 Urban Wastewater Treatment Directive, this will in most cases require secondary treatment. However, primary treatment can be accepted for plants larger than 10,000 PT with effluents to less sensitive coastal areas, if no negative environmental impacts can be proved. The main objective of the Regional Water, Sewerage and Waste Company (IVAR) is to comply with the prevailing effluent limits at lowest possible cost. During the past four years, IVAR has therefore undertaken comprehensive optimising of the precipitation process including full-scale experiments with different coagulant dosing control systems and different types of coagulants. IVAR also accomplished a feasibility study of introducing biological treatment as an alternative to chemical treatment. Under the prevailing frame conditions of discharge requirements and sludge deposit costs, it is not economically feasible to change to organic coagulants or biological treatment. This conclusion might have to be altered later resulting from the implementation of new EU regulations and increasing sludge deposit costs. This paper presents results from full-scale experiments, extracts from the feasibility study and a comparison of costs. Furthermore, the practical consequences of implementing the EU-guidelines are discussed.

Development and Optimization of a Process Combination of a Highest-Loaded Activated Sludge Stage and Biologically Intensified Filtration

1987 ◽  
Vol 19 (5-6) ◽  
pp. 981-992 ◽  
Author(s):  
W. Firk ◽  
N. Ghandehari
Keyword(s):  
Activated Sludge ◽  
Oxygen Supply ◽  
Substantial Improvement ◽  
Supply System ◽  
Advanced Treatment ◽  
Activated Sludge Process ◽  
Process Modification ◽  
Effluent Standards ◽  
Process Combination ◽  
Activated Sludge Systems

Conventional sand- and two-layer filtration is frequently put into action for the purpose of advanced wastewater treatment after low-loaded activated sludge systems. However, the effectiveness of this conventional filter concerning the biological content which is difficult to degrade (measured by COD) is extremely low - and the costs too high. In direct comparison, modifying the filters to a biologically intensified system, brings about a substantial increase in efficiency while costing very little more. The investigations of the authors for the optimization of the whole system, consisting of an activated sludge process and a biologically intensified filter, led to the fact that for the requirements of advanced treatment, the size of the activated sludge stage can be substantially reduced, without the effectiveness of the system as a whole being affected. In the field of normal requirements (national effluent standards) and comparable low influx concentrations, biologically intensified filtration can be combined with a high-loaded activated sludge process of SLR up to 5 kg BOD5/(kg MLSS.d). The area required for the construction of the system is under 50% compared to the conventional one-stage activated sludge system. At higher influx concentrations the simultaneous addition of precipitants/flocculants to the high-loaded activated sludge stage, leads to substantial improvement of the effluent of the whole system and simultaneously to a distinct phosphorus elimination. This process modification is greatly advantageous, especially for densely populated lake areas. The oxygen supply system of the filter has a key function in connection with the influent concentration and the loading of the biological stage.

Separation and recovery of phosphorus from steelmaking slag via a selective leaching–chemical precipitation process

2019 ◽  
Vol 189 ◽  
pp. 105109 ◽  
Author(s):  
Chuan-Ming Du ◽  
Xu Gao ◽  
Shigeru Ueda ◽  
Shin-Ya Kitamura
Keyword(s):  
Chemical Precipitation ◽  
Precipitation Process ◽  
Steelmaking Slag ◽  
Selective Leaching
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