Article

Coagulation, Flocculation and Clarification of Drinking Water

Authors:
To read the full-text of this research, you can request a copy directly from the author.

Abstract

The intent of this paper is to provide cursory information about coagulation, flocculation and clarification. This knowledge will provide a basis for understanding the needs of the customer wishing to monitor these processes. There is no attempt to provide an exhaustive description of various coagulants, coagulant aids, flocculants, mechanical flocculation techniques, clarification designs or configurations or a comparison of relative merits of the various designs, troubleshooting or operational theories. Consult citations in the list of references if more detailed information is desired. April, 2010.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... Horizontal paddles are again employed on a second chamber. Ozone, chlorine or chlorine dioxide applied prior to this point for disinfection credit would certainly benefit from a baffling factor of 0.7 or higher for this basin design [4]. Application of baffle for another unit process is visualised in Figure 4 that shows a rectangular clarifier with perforated inlet baffle wall. ...
... Sludge collection pipes (white colour) visible at the bottom of perforated inlet wall as shown on the left of Figure 4. On the right of Figure 4, the jet stream (red arrows) of the flocculated water can be seen entering the basin through the holes. This design would be credited with a baffling factor of 0.7 or better for purposes of calculation of CT [4]. V. CONTACT TIME (CT) VALUES Contact Time (CT) values are defined as disinfectant concentration (C) times theoretical retention time (T). ...
... Clarifier with Perforated Inlet Baffle Wall[4] ...
Conference Paper
Full-text available
Disinfection is the most important process in water treatment in the concern of water quality and quantity. Hydraulic efficiency is a vital component in evaluating the disinfection capability of a contact system. The objective of this study is to determine free residual chlorine, fluoride and chloride in chlorine contact tank and to evaluate disinfection efficiency. Disinfection efficiency of a WTP could be determined when CTachieved ≥ CTrequired which demonstrates sufficient disinfection have been met and vice versa. Based on detection test result obtained from the in-situ test, all five WTPs have complied with the maximum allowable standards for free residual chlorine as outlined by National Standard for Drinking Water Quality. As the CT rules (CTachieved ≥ CTrequired) have been complied, the disinfection process for four WTPs was found efficient whereby the disinfection process in the chlorine contact tanks was sufficient. The information obtained on disinfection ability of the existing water treatment plant would be useful for design improvement and cost effectiveness in water treatment.
... Hydraulic clari-flocculators were recently developed and investigated in the field of water treatment through hydraulic mixing in a single basin, where combines flocculation and sedimentation (Engelhardt [3], El-Bassuoni et al. [4]). Moreover, hydraulic clari-flocculators provide excellent solids contact, accelerated floc formation and exceptional solids capture. ...
... This concept was applied in different designs (e.g. Spiracone TM by Siemens, and Claricone ® by CB& I, Inc.) (Engelhardt [3]).On the other hand, El-Bassuoni et al. [4] presented an innovative system for water clarification that depends on hydraulic clari-flocculation by in-line mixing and it merges flocculation and clarification Gravity sedimentation has different applications in the primary treatment of sewage; it occurs in grit removal chambers as well as primary clarifiers, which remove about 65% of TSS, and about 35% of BOD 5 . The settling rate was controlled by Stoke's law (Richardson et al. [5], Crittenden et al. [6]), whereas the centrifugal force is utilized to enhance solids separation in different applications (McCable et al. [7], Chiang [8], Davailles et al. [9], Xu et al. [10], Brennan et al. [11], and Yuan Hsu et al. [12]). ...
... In the present study, prototypes of swirl flow hydraulic clari-flocculator as shown in figures (2b),and (2-c) can be developed as modifications of the conventional primary sedimentation tank as shown in figure (2-a) (Metcalf & Eddy [15]), where flocculation and sedimentation processes can be amalgamated. In addition, the tangential inlet facilitates swirling flow and hydraulic mixing to generate a tapered velocity gradient from its level to the end of the flocculation zone (Engelhardt [3]). The primary sedimentation tank shown in figure (2-a), was designed to treat 5000 m 3 /d of de-gritted raw sewage in 2 hours of retention time with surface loading rate of 30 m 3 /m 2 /d to remove about 35% of BOD 5 , and 65% of TSS (Metcalf & Eddy [15]). ...
Article
Full-text available
Chemical pre-precipitation becomes one of the best options of chemical treatment of sewage. In the present study, chemical pre-precipitation was processed via swirl flow hydraulic clari-flocculators, which were investigated using the steady state analysis versus the simulation using of computational fluid dynamics (CFD) software for the optimal model configuration, as well as the design equations of swirl flow hydraulic clari-flocculators were derived in the present study. From the obtained results, it can be demonstrated that up flow flocculation relatively improves regularity of tapering of velocity gradient rather than down flow flocculation. Furthermore, gravitational acceleration helps to form supplementary tapering in values of velocity gradients for up flow flocculation in contrast to down flow flocculation where gravitational acceleration negatively affects on tapering of velocity gradient.
... Swirl flow hydraulic clari-flocculators can be depicted as reactor clarifiers without mechanical mixing. These types of clarifiers were created and investigated in the field of water treatment through hydraulic mixing in a single basin (Davailles et al., 2012;Engelhardt, 2010;El-Bassuoni et al., 2005;Chaing, 2005). On the other hand, Ayoub et al. (2013) developed two models of hydraulic clariflocculators for chemically enhanced primary treatment of sewage (CEPT). ...
... These models were produced as modifications of the conventional primary sedimentation tank, where flocculation and sedimentation processes can be merged. Moreover, the tangential inlet facilitates swirling flow and hydraulic mixing to generate tapered velocity gradient (G-values) from its level to end of the flocculation zone Engelhardt, 2010). Ayoub et al. (2013) demonstrated that tapering of velocity gradient is more regular in up flow than down flow hydraulic clari-flocculator due to impact of the gravitational acceleration. ...
... A flow direction is up flow from the tangential inlet in the flocculation zone to end of the clarification zone. The tangential inlet facilitates swirling flow and hydraulic mixing to generate tapered velocity gradient from its level to end of the flocculation zone as shown in figure (2) Engelhardt, 2010). According to design criteria of the clarifiers, the ranges of diameter between 10-40 m as well as diameter of sludge hopper to diameter of the clari-flocculator ratio (Φ s /Φ t ) between 0.2-0.8 were selected to be investigated in the present study. ...
Conference Paper
Full-text available
Hydraulic flocculation becomes a promising approach that commonly used for water and wastewater treatment works because of less energy and maintenance costs are needed when compared with mechanical flocculation. Swirl flow hydraulic clari-flocculators can be described as reactor clarifiers without mechanical mixing. The best sizing of sludge hopper and investigation of the optimum diameter aspect ratio by computational fluid dynamics are the main objectives of the present study for optimal configuration of swirl flow hydraulic clari-flocculators. The obtained results reveal that the optimum diameter aspect ratio ranges between 0.2-0.4 for optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper.
... Swirl flow hydraulic clari-flocculators can be depicted as reactor clarifiers without mechanical mixing. These types of clarifiers were created and investigated in the field of water treatment through hydraulic mixing in a single basin (Davailles et al., 2012;Engelhardt, 2010;El-Bassuoni et al., 2005;Chaing, 2005). On the other hand, Ayoub et al. (2013) developed two models of hydraulic clariflocculators for chemically enhanced primary treatment of sewage (CEPT). ...
... These models were produced as modifications of the conventional primary sedimentation tank, where flocculation and sedimentation processes can be merged. Moreover, the tangential inlet facilitates swirling flow and hydraulic mixing to generate tapered velocity gradient (G-values) from its level to end of the flocculation zone Engelhardt, 2010). Ayoub et al. (2013) demonstrated that tapering of velocity gradient is more regular in up flow than down flow hydraulic clari-flocculator due to impact of the gravitational acceleration. ...
... A flow direction is up flow from the tangential inlet in the flocculation zone to end of the clarification zone. The tangential inlet facilitates swirling flow and hydraulic mixing to generate tapered velocity gradient from its level to end of the flocculation zone as shown in figure (2) Engelhardt, 2010). According to design criteria of the clarifiers, the ranges of diameter between 10-40 m as well as diameter of sludge hopper to diameter of the clari-flocculator ratio (Φ s /Φ t ) between 0.2-0.8 were selected to be investigated in the present study. ...
Article
Full-text available
Hydraulic flocculation becomes a promising approach that commonly used for water and wastewater treatment works because of less energy and maintenance costs are needed when compared with mechanical flocculation. Swirl flow hydraulic clari-flocculators can be described as reactor clarifiers without mechanical mixing. The main objective of the present study is the determination of the optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper. For this, the best sizing of sludge hopper and the optimum diameter aspect ratio were then determined by computational fluid dynamics method (CFD). The obtained results reveal that the optimum diameter aspect ratio ranges between 0.2-0.4 for optimal configuration of swirl flow hydraulic clari-flocculators in terms of tapering of velocity gradient, head loss in the flocculation zone, and sediments collection in the sludge hopper.
... The purpose of adding a coagulant is to neutralise the charge, and since most particles in water are negatively charged, any positive ion can be used as a coagulant, for example a sodium compound (such as sodium hydroxide) which contributes a monovalent ion, Na + , a calcium compound (such as calcium hydroxide) which contributes a divalent ion, Ca 2+ , and aluminium and iron coagulants which contribute trivalent aluminium ions, Al 3+ and trivalent iron ions, Fe 3+ respectively (Engelhardt, 2010). He continues by mentioning that two vs. trivalent (A 3+ ) ions is 1:60:700 respectively. ...
... The literature in general (AWWA, 1999;Schutte, 2006;Engelhardt, 2010) corroborates that neutralisation occurs very rapidly, thus the rapid mix system step or process unit should be designed so that dispersal of a coagulant in a water treatment plant is as rapid as possible. Where the coagulation process and subsequent flocculation appear to be inefficient or ineffective, it is reasonable to suspect inadequate mixing as at least part of the cause. ...
... Table 5 below). There is an ideal range of pH for each of the compounds (Engelhardt, 2010). ...
... The colloids present in the solution can be either entrapped inside the hydroxide flocs formed, or enmesh to the surface of hydroxides. The enmeshment is defined as sweep coagulation [1][2][3][4][5][6]27]. ...
... The reduction of COD and color was deceased when at low temperature and high temperature of the sample. It may be because the variation of sample temperature during coagulation may lead to non-representative floc formation and the convection currents will interfere with settling [1][2][3][4][5][6]27]. ...
Article
Full-text available
Aluminum is a valuable material, which can be used for water and wastewater treatment. It exists in metal as well as in salt form. The efficiency of water and wastewater treatment depends upon the technology applied to treat. Sugarcane industry is coming under those industries which have a large amount of freshwater and release large amount of effluent. The goal of this research work is to study the behavior of aluminum metal and salt for the treatment of sugar industry wastewater on chemical oxidation and electrochemical oxidation. The effect of pH, dosing, temperature and catalysis on metal and salt has been also studied with both treatment methods. The results show that maximum 90% of chemical oxygen demand and 94% of color removal can be achieved with an aluminum electrode (electrocoagulation) at optimum conditions, pH 7, current density 178 A/m², electrode distance 20 mm, and salt solution 0.5 M NaCl. In the same way, 81% chemical oxygen demand and 85% color removal were achieved with alum for the 0.5 M lime solution, at 50 mM mass loading, 21 °C operating temperature and optimum pH of 7, respectively. The sludge generated after treatment was also analyzed with settling filtration, thermal, FTIR and SEM.
... When FeCl 3 is added to water, it hydrolyzes, consuming alkalinity, and thus has a significant effect on pH. However, coagulants like alum or Polyaluminum chloride (PACl) are pretreated during their manufacture and thus do not show a significant impact on the pH and alkalinity [30]. The promising performance in removing suspended solids, better accessibility, and cost-effectiveness of FeCl 3 made it a better choice as a coagulant in the present study. ...
... Thus, a longer duration of settling time will enable neutralization of all the charged particles present in the water, thus improving the efficiency of turbidity and TSS removal. The present study agrees with a study performed by James et al., which confirmed that removal efficiencies were higher over a longer period [30]. Studies carried out by Muhammad et al. also indicated that the use of FeCl 3 showed enhanced turbidity removal upon a prolonged settling period of 3 h compared to other coagulants [41]. ...
Article
Full-text available
Tile industry wastewater is known to contain a high concentration of TSS and turbidity resulting from various raw materials. In the present study, the effectiveness of the coagulation process on turbidity and TSS removal from Kuwait ceramic tile industry wastewater was investigated using ferric chloride as a coagulant. The experiments were conducted using jar tests to determine the optimum operating conditions of coagulant dosages, pH, and settling time. It was found that the coagulant dosage and medium pH greatly affect the efficiency of the coagulation process. A gradual increase in coagulant dosage from 10 to 50 mg/L increased the efficiency of turbidity removal from 95.6% to 99.5%. The efficiency of the coagulation process was also found to be dependent on pH values, where higher pH improved the efficiency of turbidity removal. It was found that a medium pH of 10, 1 h settling time, and 50 mg/L of coagulant dosage are the optimum process conditions to achieve almost complete removal of turbidity (99.5%) and TSS (99.8%). This study concluded that coagulation might be useful as a primary wastewater treatment process for tile industry wastewater.
... Hydraulic clari-flocculators have been recently investigated in the field of water treatment through hydraulic mixing in a single basin, where combines flocculation and sedimentation (Engelhardt, 2010), and (El-Bassuoni et al., 2005). Moreover, hydraulic clari-flocculators provide excellent solids contact, accelerated floc formation and exceptional solids capture. ...
... In the present study, prototypes of swirl flow hydraulic clari-flocculator as shown in figures (2b),and (2-c) can be developed as modifications of the conventional primary sedimentation tank as shown in figure (2-a) (Metcalf & Eddy, 2003), where flocculation and sedimentation processes can be amalgamated. In addition, the tangential inlet facilitates swirling flow and hydraulic mixing to generate a tapered velocity gradient from its level to the end of the flocculation zone (Engelhardt, 2010). The primary sedimentation tank shown in figure (2-a), was designed to treat 5000 m 3 /d of degritted raw sewage in 2 hours of retention time with surface loading rate of 30 m 3 /m 2 /d to remove about 35% of BOD 5 , and 65% of TSS (Metcalf & Eddy, 2003). ...
Conference Paper
Full-text available
Chemical pre-precipitation becomes one of the best options of chemical treatment of sewage. In the present study, chemical pre-precipitation was processed via swirl flow hydraulic clari-flocculators, which were investigated using the steady state analysis versus the simulation using of computational fluid dynamics (CFD) software for the optimal model configuration, as well as the design equations of swirl flow hydraulic clari-flocculators were derived in the present study. From the obtained results, it can be demonstrated that up flow flocculation relatively improves regularity of tapering of velocity gradient rather than down flow flocculation. Furthermore, gravitational acceleration helps to form supplementary tapering in values of velocity gradients for up flow flocculation in contrast to down flow flocculation where gravitational acceleration negatively affects on tapering of velocity gradient.
... Further increase in mass loading decreases the treatment efficiency. This may be due to destabilization of the particles as the charge reversal on the colloids occurs (Engelhardt, 2010;Aboulhassan et al., 2014). This shows that the combined treatment has better efficiency than single coagulant process, which brings the water up to discharge limit. ...
Article
Full-text available
Sugarcane is valuable crop of India and have major role for foreign exchange. The aim of research work is to investigate the reduction of chemical oxygen demand and color from sugarcane industry effluent by thermolysis and coagulation method. The complete study was done in batch mode to determine the effect of operating parameters. The result shows maximum 73% of chemical oxygen demand and 76% color removal with copper oxide catalyst at 5Kg/m3 massloading, 85°C reacting temperature, 9hrs treatment time and pH 8. Combined study shown 97.6% chemical oxygen demand and 99.9% color removal at pH 6.5 and mass loading 8mM with copper sulphate salt. The settling and filtration was found to be good at 65°C and 75°C with copper oxide treated sugar industry wastewater.
... In addition, coagulant overdosing will inevitably result in excessive sludge formation and increased chemicals and residuals management costs. In underdosing the amount of coagulant is not sufficient to neutralise the colloidal and optimum dosing mechanism of coagulation is relevant (Engelhardt 2010). ...
Article
Full-text available
Iron materials play a vital role for the treatment of water and wastewater. It is available in different forms and is applied in different ways according to the methodology required. This investigation was carried out to determine the treatment efficiency of ferrous compound in chemical and thermal oxidation process to treat sugar industry wastewater. The results show 74.5% chemical oxygen demand, 87% color reduction by chemical treatment and 73% chemical oxygen demand, 79% color reduction by thermal treatment with ferrous sulfate salt. Iron compounds show 20:80 solid–liquid interface after 125 min of settling, filter medium resistance 1.56 × 10⁻¹² and cake resistance 1.30 × 10⁻¹⁴ m/kg with chemical coagulation. Generated sludge has less inorganic material and functional groups and can be used as fertilizer for agriculture crops.
... Briefly, zeta potential measures the level of charge neutralization on colloids after coagulation. Zeta potential can be negative, zero or positive (Engelhardt, 2010). Negative, zero and positive results mean inadequate, ideal and overfeed of coagulant respectively. ...
Article
Full-text available
Conventional water treatment is constrained by factors such as variation in raw water quality, inefficient coagulation, use of inappropriate sand for filtration, and poor backwashing process among others. The objective of this study was to find out the impact of daily and seasonal variation of raw water quality on conventional water treatment through the jar testing process. Short filter run times as low as 12 h were experienced at Gaba complex requiring emergency backwashing. The short filter run times were envisaged to be resulting from the inability of the coagulation process to cope with the varying water quality. Generally, the pH of the water samples showed no significant (p>0.05) difference in both the dry and wet period. The water turbidity and colour were significantly (p<0.05) higher in the dry period compared to the wet period. The optimum alum dose (60 to 70 mg L-1) for each jar test showed up to 92% turbidity removal and complete colour removal. Variation in the raw water quality both daily and seasonally did not significantly (p>0.05) affect the amount of coagulant required for optimal water treatment. The short filter run times therefore, could be due to other factors to be investigated.
... The criteria for the discharge of wastewater are becoming stricter to prevent the environment contamination and/or the infection of drinking water sources. Before use the water must be treated, and must be ensure that it is free of pathogens and chemicals posing a risk to health [3]. Coagulation/flocculation is considered the most important process in surface water treatment. ...
... One of the advantages with the use of these flocculent in AMD treatment is their flexibility to withstand turbulence by mechanical agitation as they do not form a highly viscous compound. As the flocculent contain constituents of both the coagulants (Fe 3+ ) and the neutralizing agents (Ca 2+ and Mg 2+ ), destabilize is by charge neutralization and particle bridging [19], as afore-mentioned (Eq. 3). ...
Article
Full-text available
Acid mine drainage (AMD) from decant in Krugersdorp (South Africa) was dosed with acid-free polyferric chloride (af- PFCl) of CaOH2 or MgOH2 (PFCl-Ca(OH)2 or-Mg(OH)2). A 200 mL sample was poured into five 500 mL glass beakers and the flocculent was added in a jar test respectively using different methods of mixing and dosing. The mechanism tests were performed employing two methods of dispersing reagents throughout the colloidal suspension, i.e., rapid mixing and shaking in order to find the removal mechanism of mineral salts and relationship between the removal and characteristics of flocculent/pollutants. The results showed that the turbidity removal efficiency exhibited by FeCl3, PFCl-Ca(OH) 2 or Mg(OH)2, and hydroxides of Ca or Mg is identical, all above 90%. It also revealed that the effective AMD treatment is not necessarily dependent upon the pH, but the ability of the coagulant to destabilize the double layer (high electronegativity) of an aqua-colloid and optimal hydrolysis. The residual turbidity of the AMD samples at 15, 25 and 35°C does not exhibit significant deviations. The turbidity removal of the samples with low temperature shows that dynamic viscosity of the colloidal suspension has an influence in the destabilization-hydrolysis reaction.
... Unfortunately, these conventional water clarification treatment systems,at times, are unable to eliminate all those contaminants that polluted the river water, thereby, they might enter the distribution and supply network [2]. The existing process of coagulation and flocculation are using chemicals known as cationic coagulants such as alum, ferric sulfate, calcium oxide, and organic polymers [3]. Chemical coagulation is usually accomplished by adding metallic salts like aluminum sulfate (alum) or ferric chloride. ...
Article
Full-text available
The existing process of coagulation and flocculation is using chemicals that known as the cationic coagulant such as alum, ferric sulfate, calcium oxide, and organic polymers. Thus, this study focuses on optimizing of the flocculation process by microbial coagulant in river water. Turbidity and suspended solids are the main constraints of river water quality in Malaysia since they may reduce the dissolved oxygen in the water and affects the aquatic life. Hence, a study is conducted to produce microbial coagulants isolated locally for river water treatment. The chosen microbe used as the bioflocculant producer is Aspergillus niger. The parameters optimized in the flocculation process were pH, bioflocculant dosage and effluent concentration. The research was done in the jar test process and the process parameters for maximum turbidity removal was validated. The highest flocculating activity was obtained on day seven of cultivation in the supernatant. The optimum pH and bioflocculant dosage for an effective flocculation process were between 4-5 and 2-3 ml for 0.3 g/l of effluent concentration, respectively. The model was validated by using a river water sample from Sungai Pusu (Pusu river) and the result showed that the model was acceptable to evaluate the bioflocculation process.
... It will be good to mention that the pH of the effluent from the coagulation process reached about 6. Actually, by adding ferric salt to the solution, it works by reacting with wastewater's alkalinity [26,27]. The 0.92 mg/L of alkalinity is consumed by each mg/L of ferric chloride [28]. Therefore, it led to the reduction of pH to about 6. ...
Article
In this study, the treatment of pulp and paper wastewater using combined approach of coagulation/ sulfate radical-advanced oxidation process (SR-AOPs)/ultrafiltration (UF) was studied in the lab scale. In the beginning of this system, the performance of three coagulants such as polyaluminum chloride (PACl), ferric chloride (FeCl3) and alum was evaluated to achieve high recycled fiber. According to the results yielded, the FeCl3, with high fiber recycling (98%) and removal efficiency, was more efficacious. In the next step, the potassium persulfate (PPS)-Fe(II) and PPS-Fe(III) efficiency in the removal of the chemical oxygen demand (COD), aromatic compounds (UV254) and the value of sludge volume index were evaluated using Taguchi design of the experiment. The results showed that the removal efficiency of COD and UV254 in the process of PPS-Fe(II) was 92.6% and 95.8% which had the better performance than the process of PPS-Fe(III). The results showed that electrical conductivity (EC) in coagulation/SR-AOPs had increased to 30.64%. Moreover, there was a significant amount of sulfate in the effluent; whereas, UF was applied. Accordingly, using UF after pretreatment by coagulation/PPS-Fe(II), the removal efficiency of sulfate, EC, COD and UV254 increased to 99.44%, 62.05%, 97.35% and 98.75%, respectively.
... In this process, coagulants are added which will at first cause the colloidal particles to become destabilized and bunch together. When pieces of floc bunch together, they may form larger, heavier flocs which settle out and are removed as sludge [5]. The most commonly used commercial coagulants in water purification are aluminum and iron salts [6]. ...
Article
Coagulation and flocculation followed by sedimentation are the customarily used unit operations in conventional water treatment process. Usually the process of coagulation is carried out using different metal salts such as aluminum and iron oxides. Therefore, this study was aimed at evaluating the performance of mix-chemical coagulants in water purification process. An experimental comparative study was done by evaluating controlled factors under various experimental setups. Jar tests were conducted to assess the efficiency of alum and ferric chloride coagulants in dual (1:1 and 3:1 alum to ferric chloride) combinations as well as separately. ANOVA tests were performed to select the best performing coagulant using Minitab version 16. The highest percentage TDS removal performance of 55.8%, 72.6%, 81.4% and 81.4% were exhibited for alum, ferric chloride, 1:1 and 3:1 alum-ferric chloride combination. And the highest percentage COD removal performance of 71%, 58.1%, 63.6%, and 50.9% was demonstrated for alum, ferric chloride, 1:1 and 3:1 alum-ferric chloride combination, respectively. The highest percentage turbidity removal performance shown by alum, ferric chloride, 1:1 and 3:1 alum-ferric chloride combination were 98.7%, 99.1%, 98.7% and 97.8%, respectively. The 1:1 alum-ferric chloride coagulant combination shows highest (80.8%) concurrent TDS, COD, and turbidity average removal. The result of this study indicated that 1:1 alum-ferric chloride was found the most suitable coagulant to perform the coagulation process for the removal of COD, TDS and turbidity simultaneously. The use of optimized alum-ferric chloride combinations as a coagulant is preferable to single coagulant use if appropriately managed.
... For pretreated sugar waste, 3 mM mass loading was used resulting in 91% COD reduction and 93% color removal (using Fe 2 (SO 4 ) 3 ) and 92% COD reduction and 94% color removal (using FeCl 3 ) was observed at pH 6.5, which presented in Fig. 7(b). The optimum pH 6.5 may be due to the fact that ferrous and ferric ions at this pH are exhibit in dominating cation, which naturalized the negative colloidal and precipitated impenetrable weighty floc (Engelhardt, 2010). ...
Article
Full-text available
The growth of any nation depends upon the contribution of industrialization. Sugarcane industry is among one of them. It required a large quantity of fresh water for processing and release the large quantity of wastewater. This discharge has a major effect on the Environment and receiving bodies. To protect the surrounding environment an attempt has been made to treat the sugar industry wastewater by electrocoagulation and coagulation process. The result shows that treatment with electrocoagulation could achieve 85% chemical oxygen demand (COD) reduction and 89% color reduction at initial pH of sample 6.5, electrode distance 20 mm, current density 156 Am ⁻² and electrolyte concentration 0.5 M (NaCl). Addition of ferric salt as chemical coagulant after electrocoagulation treatment shows an overall 98% COD reduction and 99.7% color reduction at same pH with 5 mM coagulant mass loading. The sludge generated after treatments are found suitable for the alternative application.
... For example, the relative effectiveness of monovalent (Na + ), divalent (Ca 2+ ), and trivalent (Al 3+ ) ions is 1:60:700, respectively. It shows that the trivalent of aluminum ions is 700 times more effective regarding charge neutralization compared to monovalent ion (22). ...
Article
Full-text available
Landfill leachate is highly polluted and generated as a result of water infiltration through solid waste produced domestically and industrially. This study investigated the applicability of the response surface methodology (RSM) to optimize the removal performances of chemical oxygen demand (COD), color, and suspended solids (SS) from landfill leachate by coagulation process using Tin tetrachloride pentahydrate. The leachate samples were collected from Alor Pongsu Landfill (APLS) in Perak, Malaysia. Before starting the experiments, general characterization was carried out for raw leachate samples to investigate their physical and chemical properties. The effects of the dosage and pH of SnCl4 on the removal performances were evaluated as well. An ideal experimental design was performed based on the central composite design (CCD) by RSM. In addition, this RSM was used to evaluate the effects of process variables and their interaction toward the attainment of their optimum conditions. The statistical design of the experiments and data analysis was resolved using the Design-Expert software. Further, the range of coagulant dosage and pH was selected based on a batch study which was conducted at 13000 mg/L to 17000 mg/L of SnCl4 and pH ranged from 6 to 10. The results showed that the optimum pH and dosage of SnCl4 were 7.17 and 15 g/L, respectively, where the maximum removal efficiency was 67.7% for COD and 100% for color and SS. The results were in agreement with the experimental data with a maximum removal efficiency of 67.84 %, 98.6 %, and 99.3%, for COD, color, and SS, respectively. Overall, this study verified that the RSM method was viable for optimizing the operational condition of the coagulation-flocculation process.
... Coagulant chemicals with charges opposite to those of the suspended solids are added to the water to neutralize the negative charges on non-settleable solids (such as clay and colour-producing organic substances). Increasing the dosage of the coagulant would imply that more charges are employed to neutralize the negative charges in waste water which will make the particles to agglomerate and settle, this will in turn reduce the turbidity of the coagulated mixture as the suspended solids would have settled [10]. The dosage of raw fly ash that gave the lowest turbidity was found to be 0.25 g/l with a residual turbidity of 1.85 NTU. ...
Article
Full-text available
Fly ash was explored as a raw material for the production of three fly ash-based coagulants being raw, calcined and calcined-sodium hydroxide complex coagulants. Calcined fly ash and calcined fly ash-sodium hydroxide complex coagulants were prepared by calcining raw fly ash at a temperature of 800ºC and all three were acid washed with hydrochloric acid before being used as coagulants. A fly ash sample from a local coal fired power plant was characterization by means of an XRD and FTIR. The characterization results revealed the presence of various compounds which included quartz, hematite, magnetite, anhydrite, and ettringite with a large characteristic peak showing quartz at approximately 26º ≈ 2θ. The behaviour of the prepared coagulants in treating waste water was investigated at different turbidity ranges of low (19 NTU), medium (49 NTU) and high (80 NTU) in jar test experiments. Coagulant doses were also varied at these different turbidity levels to determine the dosage that gives the lowest turbidity for all the three coagulants. From this study, we observed that an increase in coagulant dose from 0.05 to 0.25g/l led to a decrease in residual turbidity. Calcined fly ash was more effective at low and medium turbidity at a dosage of 0.20 g/l whereas Calcined fly ash-sodium hydroxide complex coagulant was found to be more effective with the highest % reduction of 99.8% at a higher turbidity for the same dose.
... Coagulant like Sodium aluminate (NaAlO 2) has been used in wastewater treatment in the phosphorous removal process. While the other aluminium and iron salts act as acids consuming alkalinity, sodium aluminate acts as a base [6]. The electro-coagulation (EC) technology [7,8] can also be used to treat abattoir wastewater for safe discharge. ...
Article
Full-text available
The use of coagulation-flocculation process as means of wastewater treatment is gradually becoming more popular. This research work is to evaluate the efficiency of coagulation-flocculation process in the treatment of abattoir effluent. Samples of abattoir effluent were collected from a slaughterhouse at Ede, Nigeria, and Alum was used in the coagulation-flocculation treatment of the effluent. The physico-chemical and bacteriological analyses of the untreated and treated effluent were carried out and these were used in determining the efficiency of the treatment process. The values obtained (from the physico-chemical and bacteriological analyses) were also compared with the effluent standard of Environmental Protection Agency (EPA). Coagulation-flocculation process performed efficiently in reducing the contaminant level of Colour, TDS, Turbidity, Conductivity, TSS, Total Hardness, COD, Coliform, metals and other pollutants from the effluent.
... Tin (IV) chloride is an inorganic tin compound, which is tetravalent metal-based. Theoretically, the higher value of the electrolyte's oppositely charged ion indicates better coagulation mechanism (Engelhardt and Terry, 2014). ...
Article
Stabilised leachate usually contains lower concentration of organic compounds than younger leachate; it has low biodegradability and generally unsuitable for biological treatment. The effectiveness of tetravalent metal salts in a coagulation-flocculation (C–F) process is still inclusive. Application of natural coagulants as an alternative to the chemical could reduce chemical usage, is less costly, and environmentally friendly. Hence, the objective of the current research is to examine the possibility of reducing the amount of Tin (IV) chloride (SnCl4) as a primary coagulant by adding Jatropha curcas (JC) as a flocculant as a sole treatment through the C–F process in treating concentrated suspended solids (SS) (547 mg/L), colour (19,705 Pt–Co) and chemical oxygen demand (COD) (4202 mg/L) in stabilised landfill leachate. The work also aims to evaluate the sludge properties after treatment. Functional groups, such as carboxylic acids, hydroxyl and amine/amino compounds (protein contents), were detected in the JC seed to facilitate the C–F process by neutralising the charge pollutant in water and cause the possibility of hydrogen bonding interaction between molecules. The combination of JC seed (0.9 g/L) as a flocculant reduced the dosage of SnCl4 as a coagulant from 11.1 g/L to 8.5 g/L with removals of 99.78%, 98.53% and 74.29% for SS, colour and COD, respectively. The presence of JC improved the sludge property with good morphology; the particles were in a rectangular shape, had clumps and strong agglomeration. These properties of sludge proved that JC seed could enhance the adsorption and bridging mechanism in the C–F procedure.
... The high coagulating power of multivalent ions is caused by their propensity to form hydrolysed products that have specific adsorption ; the higher the valence, the higher the contribution of specific adsorption in the coagulation process202122. For drinking water application, the relative effectiveness of charge neutralization by Na + , Ca 2+ and Al 3+ ions is in the ratio of 1:60:700, respectively [23]. In this paper, we report results of investigations conducted on the coagulation performances of tetravalent titanium and zirconium salts, in comparison with the conventional coagulant, alum. ...
... Both E. coli and MS2 would have negative surface charges in the test water. However, because MS2 is smaller and has a larger surface-area-tomass-ratio, the negative surface charge may play a larger role in its mobility and interaction with other constituents in the water, and possibly make it more effectively removable by chitosan coagulation, as compared to E. coli KO11 [33]. ...
Article
Full-text available
The World Health Organization (WHO) estimates 2.1 billion people lack access to safely managed water. Cloth filtration is often employed in rural and developing communities of South Asia for point-of-use water treatment, but bacteria and viruses are too small for efficient removal by this filtration method. Chitosan is a biodegradable, cationic, organic polymer derived from the chemical treatment of chitin that acts as a coagulant and flocculant of contaminant of microbes and other particles in water, thereby facilitating filtration of microbes. This research 1) evaluated the use of chitosan acetate as a pre-treatment coagulation-flocculation process followed by cloth filtration for microbial reductions and 2) assessed floc particle size under three stirring conditions. E . coli KO11 bacteria and MS2 coliphage virus removals were quantified using culture-based methods. Chitosan acetate coagulation-flocculation pre-treatment of water, followed by cloth filtration, met or exceeded the protective (2-star) WHO performance levels for bacteria (2 log 10 reduction) and viruses (3 log 10 reduction), and filtrate turbidity was consistently reduced to < 1 NTU, meeting United States Environmental Protection Agency (EPA) and WHO targets.
... Coagulation treatment is a method involving the use of certain chemicals called coagulants, traditionally alum (aluminum sulfate Al2(SO4)3), ferric chloride (FeCl3), or ferrous sulfate (FeSO4) to neutralize charges and form gelatinous large mass of particles which when settled can be trapped by filtration (34) . It is the application of chemical substance called coagulant to enable the agglomeration and settling of suspended and colloidal particles in wastewater. ...
Thesis
Full-text available
Food industries produce large quantities of organic wastewater which creates high biological and chemical oxygen demand in surface water. The textile industry is also a major contributor of dye wastewater into the water bodies affecting the water quality in relation to light transmissivity. This study focused on the treatment process of coagulation on a combined mixture of dye and flour wastewater. Synthetic dye and flour wastewater prepared in the laboratory was used and the flour used to prepare the flour wastewater was bought from the grocery store. The treatment was carried out using four different concentrations of wastewater. Using UV-Vis Spectrophotometer, the effectiveness of the coagulation process was measured for Transmittance, Absorbance, and total organic carbon (TOC) as indices. It can be concluded that coagulation process is an effective preliminary treatment process for suspended particles, organics, and color removal from industrial effluent.
... Moreover, the least pH variation was recorded with the application of these mixtures; these results were obtained using jar test apparatus with 15 minutes of flocculation followed by 30 minutes of sedimentation rather than 2 hours in the conventional primary sedimentation. This requires redesign and restructuring of the conventional primary sedi-mentation tanks to double their design discharges (Engelhardt, 2010;Rashed et al., 2013b). ...
Article
Full-text available
The communities with high population density suffer from limited land availability for construction of new sewage treatment plants or expansion of the existing plants, which suffer from receiving of excess hydraulic and/or organic loads. The undertaken work is devoted to investigate the feasibility of upgrading these plants using chemically enhanced primary treatment (CEPT) with hydraulic clari-flocculation. CEPT produces large amounts of primary sludge, which can be digested anaerobically to produce biogas. The results showed that a homogenous mixture of 67% alum and 33% sea-salt by weight can be used with dose of 40 mg/L as a suitable coagulant in addition to a range between 60-90 m/d of surface overflow rate as the optimum conditions for CEPT of sewage. These conditions result in removal efficiencies in the range between 52-70% of BOD5, 54-68% of COD and 76-88% of TSS. These results enable the primary sedimentation tank (PST) to accommodate double of its design capacity with very simple modifications in the raw sewage inlet to be chemically enhanced primary sedimentation tank (CEPST) according to the present study. In addition, CEPT maintains the operational conditions of activated sludge system in the recommended limits. Finally, CEPT for upgrading the present WWTP is definitely advantageous in reducing the capital costs by 30% and the treatment costs by 28%.
Conference Paper
In this study, dynamic modelling of a coagulant dosage system using the principle of continuously stirred tank reactor (CSTR) is proposed for effective coagulation control in water treatment process. The multi-input multi-output (MIMO) system dynamics of the model are estimated using prediction error method (PEM) and autoregressive moving average with exogenous input (ARMAX) technique. Simulations results and comparative analysis show that PEM model estimates the system parameters better than the ARMAX model. In addition, the proposed dynamic model will serve as a viable alternative to the widely used data-based modelling techniques for coagulation control. It will adequately support the development of an efficient multivariable control strategy that will outperform the existing standard Proportional Integral (PI) feedback control strategy commonly used in water treatment coagulation process.
Article
Bioflocculants like polysaccharides are excellent alternatives to harmful synthetic flocculants and usability under stricter levels of ecosystem protection. In this study, an exopolysaccharide producing strain Paenibacillus sp. M21629 was isolated. The exopolysaccharide was abundant in carboxylic groups and named floccuronic acid with a high weight average molecular weight of 2.38 × 10⁸ Da. The hexasaccharide repeating units of floccuronic acid were →3)-α-D-Manp-(1 → 3)-4-Suc-β-D-Manp-(1 → 3)-β-D-Glcp-(1 → 4)-β-D-GlcpA-(1 → 4)[4,6-Pyr-β-D-Galp-(1 → 3)]-β-D-Galp-(1→. The floccuronic acid at 0.5–1 ppm showed high turbidity removal efficiency in kaolin suspension (99.8%), coal wastewater (98.8%), and high-turbidity drinking water (89.2%). The flocculation ability of floccuronic acid depended on the instability of solid particles. Owing to these encouraging results, floccuronic acid is expected to be a useful bioflocculant applied in wastewater treatment and the utilization of water resources.
Article
Introducción: La materia orgánica es un factor causante del deterioro del medio natural y de las aguas superficiales, sin embargo, la medida directa y contínua de esta, ya sea COT, DBO5, DQO, tienen un nivel de dificultad y costo relativamente alto. Un método utilizado para monitorear la carga orgánica en tiempo real es mediante el coeficiente de absorción espectral a una longitud de onda de 254nm (SAC254). Objetivo: Evaluar la precisión y el nivel de correlación de datos de la DQO y valores de SAC254. Materiales y métodos: Se realizaron dos pruebas prácticas de sistemas de medición de carga orgánica con esta tecnología (SAC254), tanto en una PTAR de agua residual de la empresa Sedapal como en una PTAR industrial de la papelera Protisa. El sistema de medición empleado estuvo formado por un sensor en línea con capacidad de lectura del coeficiente de absorción espectral (SAC254) y un registrador de datos capaz de correlacionar los parámetros SAC254 y DQO. Resultados: El sistema de medición presentó un error promedio del 13%, mostró ser una herramienta práctica por su fácil manipulación, no precisa de reactivos y se adaptó tanto al agua residual doméstica como industrial. Conclusión: Los sistemas de medición instalados nos permitieron constatar que efectivamente existe una relación directa del factor SAC254 y el DQO, a medida que aumenta el SAC254 también incrementa en valor el DQO y viceversa, por lo cual es un buen indicador que permitiría optimizar la eficiencia del proceso y realizar un control más eficaz.
Article
Industrialization plays a major role in a nation's growth. However, with an increase in industrial activities, pollution levels are also increasing. Among all industries, the sugar‐processing industry is one that requires large amounts of water to process the sugar, and, consequently, it discharges large amounts of water as effluent. Highly polluted wastewater brings changes to the physicochemical characteristics of the surrounding environment. Iron compounds have had a significant impact when they are used in wastewater treatment in various applications, including when they are used to minimize the pollution levels in sugar industry wastewater (SIWW). To minimize the pollutant levels from SIWW, iron compounds have been key for uses in treatments involving chemical and electro‐oxidation. Two different methodologies of electrocoagulation and chemical coagulation have been used to treat SIWW. In electrocoagulation, an iron plate is used as an electrode material under specific operating conditions. Ferrous sulfate and ferric chloride have been used as chemical coagulants at various pH and mass loading levels. The use of iron metals shows an 82% reduction in chemical oxygen demand (COD) and an 84% reduction in color at the optimum condition of pH 6, an electrode distance of 20 millimeters, and a current density of 156 square centimeters. As a chemical coagulant, iron salt (ferrous sulfate) provides a reduction of 77% COD and a 91% reduction of color at pH 6 and a 40‐millimole mass loading. Electrochemical treatment using iron was found to be suitable to treat SIWW. The sludge generated after treatment can be burned or composted with the possible recovery of some of the treatment costs.
Article
This study was conducted to evaluate the effect of the toxicity levels of the coagulation and flocculation process on raw and treated leachate using acute toxicity tests. Tin tetrachloride (SnCl4) and the Jatropha curcas (JC) seed was used as coagulant and coagulant aid to remove concentrated Suspended Solids, SS (534 mg/L), colour (19,297 Pt‐Co), and Chemical Oxygen Demand COD (4,188 mg/L) in a stabilised landfill leachate. The toxicity effects on local red tilapia fish (Oreochromis niloticus) were investigated, which involved three main steps, namely acclimatisation, range‐finding test, and short‐term definitive test. The presence of JC seed (0.9 g/L) as a flocculant reduced the dosage of SnCl4 from 11.1 to 8.5 g/L and exhibited good removals of 99.78, 98.53, and 74.29%, respectively, for SS, colour, and COD. The toxicity test indicated that only 5 fishes died in the first 12 hours for the treated sample compared to 7 deaths for untreated leachate. In 96 hours, a total of 42 and 31 mortality rates were noted for the raw and treated leachate samples, respectively. The treated sample could reduce the toxicity effects to the tested tilapia fish and is safe to be discharged at appropriate dilution concentrations.
Article
Full-text available
This document is not issued to the general public and all rights are reserved by the World Health Organization. The document may not be reviewed, abstracted, quoted, reproduced or translated, in part or in whole, without the prior written permission of WHO. No part of this document may be stored in a retrieval system or transmitted in any form or by any means -electronic, mechanical or other without the prior written permission of WHO. The views expressed in documents by named authors are solely the responsibility of those authors. Foreword Around 2.2 million die of basic hygiene related diseases, like diarrhoea, every year. The great majority are children in developing countries. Interventions in hygiene, sanitation and water supply make proven contributors to controlling this disease burden. For decades, universal access to safe water and sanitation has been promoted as an essential step in reducing this preventable disease burden. Nevertheless the target of "universal access" to improved water sources and basic sanitation remains elusive. The "Millenium Declaration" established the lesser but still ambitious goal of halving the proportion of people without access to safe water by 2015. Achieving "universal access" is an important long-term goal. How to accelerate health gains against this long-term backdrop and especially amongst the most affected populations is an important challenge.
Article
Full-text available
The promulgation of such regulations as the Interim Enhanced Surface Water Treatment Rule (IESWTR) and the Long Term 2 ESWTR (LT2ESWTR) has pointed out the need for methods to compare the relative efficacy of treatment alternatives for removing Cryptosporidium during drinking water treatment. Until recently, little was known about Cryptosporidium removal by filtration during nonideal operating periods. Furthermore, with the exception of formalin-inactivated oocysts, no reliable, quantitative surrogate for live oocysts has been demonstrated for a variety of operational conditions and filtration regimes in the peer-reviewed literature. This article consolidates and updates the available information on Cryptosporidium removal by filtration, with a focus on optimal and suboptimal filtration performance.
Article
This article discusses ultraviolet (UV) light absorption at 254 nm as a useful measurement that serves as a surrogate test for reactive natural organic matter (NOM). Operators can measure the UV‐254 of a sample with a spectrophotometer in less than 15 minutes by measuring the intensity of UV light at the proper wavelength before and after it passes through a water sample in a cell of known path length (usually 1 or 10 cm). Applying UV‐254, predicting THM4 formation, predicting 90th percentile lead, required ozone dose, and UV‐254 recommendations are all discussed.
Article
This article presents a new computer modeling program that analyzes real‐time water chemistry to help operators predict more accurately the required coagulant changes when time is limited. The article discusses how the model was used at the Grand Rapids Lake Michigan Filtration Plant, how it was linked to the plant's supervisory control and data acquisition (SCADA) system so the coagulant‐dose computer program would receive real‐time data, the two coagulation methods of charge neutralization and sweep coagulation, and using UV254 to detect organics.
Article
This article discusses recent advances in water treatment plant instrumentation and laboratory equipment that allow Mohawk Valley Water Authority (MVWA) operators to use their ingenuity to optimize water treatment. To better understand and improve the treatment process, operators have incorporated streaming current monitors (SCMs), coagulant charge analyzers (CCAs), particle counters, UV254 analyzers, and on‐line chlorine analyzers into their routine. Supervisory control and data acquisition (SCADA) system monitoring screens display data as water travels through the process train and into the distribution system.
Article
This article discusses how advances in chemical feed equipment provide options for cost‐effective alkalinity addition. In the past, carbon dioxide systems required deep basins and a significant amount of reaction time to achieve stable water. Improved technology provides a more consistent lime feed rate and a faster‐reacting lime slurry, which can allow for addition of lime after filtration without significantly affecting finished water turbidity. The use of carbon dioxide and lime allows utilities to “dial in” finished water alkalinity and pH simultaneously.
Article
Removal of NOM from the raw water is still a problem because the numerous methods used have not produced a satisfactory model for the standard drinking water quality. The registered increasing humic substances in natural water add to the purification problem. Among the many techniques of humic substances removal from water, enhanced coagulation is the most adjustable to respond efficiently to the challenge. This can be best illustrated by comparing the many techniques used, especially the coagulation by contact filtration and the alternative enhanced coagulation that efficiently remove humic substances even from the worst water compositions at the temperatures approaching zero in conventional settling units without undesirable effects of the contact filtration. The effect of humic substance removal was studied in several different types of water under laboratory and water-treatment plant conditions when conventional and enhanced coagulation methods were used.
Article
Incluye bibliografía e índice
The Quest for Pure Water
  • M N Baker
Baker, M. N., The Quest for Pure Water, Vol. 1, 2 nd ed., American Water Works Association, 1981.
Colloid science; principles, methods and applications. Terance Cosgrove Ed
  • John Eastman
Eastman, John; "Colloid Stability," Colloid science; principles, methods and applications. Terance Cosgrove Ed., Blackwell Publishing, 2005
Introduction to the Theory of the Streaming Current Meter, Application Note, Accurate Measurements NZ Ltd
  • Daniel Edney
Edney, Daniel, Introduction to the Theory of the Streaming Current Meter, Application Note, Accurate Measurements NZ Ltd.
Water Treatment By Enhanced Coagulation -Operational status and optimization issues
  • Bjørnar Eikebrok
Eikebrok, Bjørnar, "Water Treatment By Enhanced Coagulation -Operational status and optimization issues," SINTEF
Calculation of CT Values for Compliance with Drinking Water Regulations, Hach Company
  • Terry Engelhardt
Engelhardt, Terry, Calculation of CT Values for Compliance with Drinking Water Regulations, Hach Company, 2008.
Handbook of Public Water Systems
  • Hdr Engineering
  • Inc
HDR Engineering, Inc, Handbook of Public Water Systems, 2 nd ed., John Wiley and Sons, 2001.
Biological Particle Surrogates for Filtration Performance Evaluation, AWWARF
  • David Hendricks
Hendricks, David, Biological Particle Surrogates for Filtration Performance Evaluation, AWWARF, Project #181, 2000.
Water Clarification Processes, Practical Design and Evaluation
  • Herbert E Hudson
Hudson, Herbert E., Water Clarification Processes, Practical Design and Evaluation, Van Nostrand Reinhold, 1981.
Water Treatment Plant Operation
  • Kenneth Kerri
Kerri, Kenneth, Water Treatment Plant Operation, Vol. 1, California State University, 1990.
The Good, The Bad & The Successful Uses of a Streaming Current Monitor to Optimize Coagulation Dosages
  • Linda Kramer
  • John Horger
Kramer, Linda and Horger, John; "The Good, The Bad & The Successful Uses of a Streaming Current Monitor to Optimize Coagulation Dosages," City of Philadelphia Water Department. 2003
Manual of Water Utility Operations
  • Mark V Lowry
Lowry, Mark V., et. al., Manual of Water Utility Operations, 8 th ed., Texas Water Utilities Association, 1988.
Chemical Feed Field Guide for Treatment Plant Operators
  • Wm Lauer
Lauer, Wm., et. al., Chemical Feed Field Guide for Treatment Plant Operators, American Waterworks Association, 2008.
Water and Man's Health, United States Department of State, Agency for International Development
  • Arthur P Miller
Miller, Arthur P., Water and Man's Health, United States Department of State, Agency for International Development, Washington, DC, 1962.
Options for Remote Monitoring and Control of Small Drinking Water Facilities
  • Albert J Pollach
Pollach, Albert J., et. al., Options for Remote Monitoring and Control of Small Drinking Water Facilities, Battelle Press, 1999.
Everything You Want to Know About Coagulation and Flocculation
  • Louis Ravina
Ravina, Louis, Everything You Want to Know About Coagulation and Flocculation, Zeta-Meter, Inc., 4 th Ed., 1993.
Can A Utility Afford To Operate Without On-Line Toc Analyzers Considering The Requirements Of The D/DBP Rule? On-Line Vs. Grab Samples: What Are The Advantages And Disadvantages?
  • Wm J Reaves
Reaves, Wm J, et.al., Can A Utility Afford To Operate Without On-Line Toc Analyzers Considering The Requirements Of The D/DBP Rule? On-Line Vs. Grab Samples: What Are The Advantages And Disadvantages?, City Of Houston Public Works And Engineering, Water Quality Control Group, Houston, Texas, 2001
  • Clair Sawyer
  • Perry Mccarty
Sawyer, Clair and McCarty, Perry, Chemistry of Environmental Engineering, 3 rd ed., McGraw-Hill, 1978.
The Mc Clariflow -The Ultimate Upflow Solids Contact Clarifier
  • Arthur C Schlicht
Schlicht, Arthur C., The Mc Clariflow -The Ultimate Upflow Solids Contact Clarifier, Walker Process Equipment, November 1999.
Water Filtration and Cholera
  • H Synett
Synett, H., "Water Filtration and Cholera," The Medical and Surgical Reporter, H Synett, Ed., Philadelphia, Oct 21, 1893, p 643.
The Quest for Pure Water
  • Michael J Taras
Taras, Michael J.., The Quest for Pure Water, Vol. 2, 2 nd ed., American Water Works Association, 1981.
Application Note, Accurate Measurements NZ Ltd
  • Accufloc Case Study-Ngaruawahia
Accufloc Case Study-Ngaruawahia," Application Note, Accurate Measurements NZ Ltd.., August, 2009. 2. "How Can You Control Organic Contaminants?", AWWA Organic Contaminants Control Committee, Opflow, American Waterworks Association, February 2008, pp 20-21.
Coagulation and Filtration: Back to the Basics
Coagulation and Filtration: Back to the Basics, AWWA Seminar Proceeding, AWWA Annual Conference, No. 20155, June, 1981.
Coagulation and Filtration: Pilot to Full Scale
Coagulation and Filtration: Pilot to Full Scale, AWWA Seminar Proceeding, AWWA Annual Conference, No. 20017, June, 1987
Expensive Problem, Inexpensive Solution -Boost Alkalinity with Carbon Dioxide and Lime
  • Hart
  • Vincent
  • Thomas Crowley
Hart, Vincent, Crowley, Thomas, "Expensive Problem, Inexpensive Solution -Boost Alkalinity with Carbon Dioxide and Lime." Opflow, American Waterworks Association, Sept 2009.