M.S.

The study of lignin with the aim of correlating data, which may lead to a greeter utilization of this wood waste product, has been the subject of investigations since 1838. Previous investigations by Othmer, Harris, Sherrard and others have indicated that chlorinated lignin had potential value as a plastic. The purpose of this investigation was to study the chlorination reaction of lignin obtained from the black liquors of the sulfate process of paper manufacture. Results of preliminary experimental work indicated that the optimum method of chlorinating lignin was by suspending or dissolving the lignin in methyl alcohol. The sulfate lignin was chlorinated in two liter wolff flask which was equipped with a motor driven stirrer, and the chlorine flow was measured by a calibrated U-tube differential gage. The flask was charged with the alcohol-lignin mixture and chlorinated from one to seven hours. The rates of chlorine flow for the tests were 0.472, 0.85 and 1.084 gm. Cl₂/min at temperatures of 25 and 65ºC. The reactant gases were passed through a condenser to return the vaporized alcohol to the reaction flask and then into a 3 normal sodium hydroxide solution to react the excess chlorine gas. Samples of the reaction gas, which were analyzed for chlorine, were collected in a 1.5 normal sodium hydroxide solution at 10 minutes intervals. With this information the progress of the reaction could be plotted and the rate of chlorination measured. The chlorination of a suspension of lignin in methyl alcohol in a ratio of l to 20 was possible at 25°C. The critical temperature above which the lignin would not stay in solution was 43°C. The reaction was exothermic and produced an orange colored product containing 25 per cent chlorine. Increasing the rate of chlorine flow from 0.85 to 1.084gm. Cl₂/min. increased the chlorine consumption from 0.74 to 0.833 gm Cl₂/min. The chlorination of lignin dissolved in methyl alcohol produced two chlorinated products. One was precipitated as an orange red powder from solution during the chlorination reaction, and had a chlorine percentage as high as 29 per cent. The other lignin remained dissolved in the alcohol solution. When precipitated from solution by ice water this chloro-lignin was a light yellow powder with a chlorine percentage as high as 28.0 per cent. Increasing the rate or chlorine flow trom 0.472 to 1.084 gm Cl₂/min. during tests at 25°C resulted in increasing the rate of chlorination from 0.454 to 0.935gm Cl₂/min. Adding ferric chloride, as a catalyst, increased the chlorine consumption from 0.768 to 0.967 gm Cl₂/min. Raising the reaction temperature from 25 to 65°C decreased the chlorine consumption trom 0.935 to 0.768 gm. Cl₂/min. The chlorinated product showed definite bonding value when mixed with sawdust and pressed at a temperature or 112°C and pressures from 1000 to 5000 lb/in². The percentage lignin in the samples was varied from 5 to 60 per cent. The lignin-sawdust samples were light yellow in color and firmly bonded and water resistant. / Master of Science

The objective of this study was to examine the regrowth of E. coli and &. faecalis in chlorinated, secondary-treated sewage effluent using a continuous flow system. Regrowth was evaluated at varying chlorine contact times and chlorine residuals. In addition, chemical and physical characteristics of the sewage were evaluated in relation to regrowth. The results showed that while a 99% kill of E. coli could be achieved, regrowth always occurred regardless of the chlorine residual and contact time. S. faecalis never regrew in the chlorinated sewage. No single parameter could be identified as the most important in controlling the extent of regrowth. / Master of Science

The object of this was to investigation the effect of continuous mechanical mixing on the disinfection of settled domestic of settled domestic sewage with iodine. The variable investigated was the power input to the system which was a function of mixing intensity. Five experiments were run usfrtt a six-bladed turbine agitator in a fully baffled tank. The mixing intestines of the first three experiments were 0.292, 0.00748, and 0.0641 foot pounds per second per 1,000 gallons, respectively. The mixing was contInuous throughout the experiment. The last two experiments employed a mixing intensity of 0.000876 foot pounds per second per 1,000 gallons. Most Probably Number determinations of Escherichia coli were made at time intervals of 0, 0.5, 1.5, 2, 3, 4, 6, 8, and 10 minutes respectively, for each experiment. All ten minute Iodine residuals were in the range of 1.70 to 1.80 parts per million. Alt experiments were conducted at 20 degrees centigrade. Similar rates of disinfection were obtained at mixing intestines of 0.292, 0.0641, and 0.00748 foot pounds per second per 1,000 gallons. The disinfection rate at 0.000876 foot pounds per 1,000 gallons was inferior to that of the previously mentioned rates. The following conclusions were made after comparing these results with a previous investigation. 1. Similar continuous mixing disinfection occurred in the range of power to volume ratio of 0.00748 to 148 foot pounds per second per 1,000 gallons. 2. Inferior continuous mixing disinfection·occurred at the power to volume ratio of 0.000876 foot pound per second per 1,000 gallons and under the condition of no mixing. 3. A system operating at the power to volume ratio of 0.00748 foot pounds per second per 1,000 gallons for one minute·appears to provide for complete blending of iodine with the sewage under the conditions of the present Investigation. The suggested power requirement is equivalent to 9.46 x 10⁻⁶ horsepower per million gallons per day. / Master of Science

The chlorine demand correlations, which exist in the settled domestic sewage at the V.P.I. Sewage Treatment Plant between the limits of one and seven ppm, of applied chlorine dosage were determined. / Master of Science

This thesis describes an experiment to chorinate neohexane, and the resulting compounds.

In potable water preparation, chlorination is the last step before the potable water enters the distribution network. Umgeni Water Wiggins Waterworks feeds the Southern areas of Durban. A reservoir at this facility holds treated water before it enters the distribution network. To ensure an adequate disinfection potential within the network, the free chlorine concentration in the water leaving the reservoir at the Umgeni Water Wiggins Waterworks should be between 0.8 and 1.2 mg/L. The aim of this study was to develop an effective strategy to predict and control the chlorine concentration at the exit of the reservoir. This control problem is made difficult by the wide variations in flow and level in the reservoirs, together with reactive decay of the chlorine concentration. A Computational Fluid Dynamic study was undertaken to gain understanding of the physical processes operating in the reservoir (FLUENT software). As this kind of modelling is not yet applicable for real-time control, compartment models have been created to simulate the behaviour of the reservoir as closely as possible, using the results of the fluid dynamic simulation. These compartment models were initially used in an extended Kalman filter (MATLAB software). In a first step, they were used to estimate the kinetic factor for chlorine consumption and in a second step, they predicted the chlorine concentration at the outlet of the reservoir. The comparison between predictions and data, allowed the validation of the compartment models. A predictive control strategy was developed using a Dynamic Matrix Controller, and tested offline on the compartment models. The controller manipulated the chlorine concentration in the inlet of the reservoir in order to control the chlorine concentration in the outlet of the reservoir. Finally, the simplest compartment model was implemented on-line, using the Adroit SCADA system of the plant, in the form of a Kalman filter to estimate the chlorine decay constant, as well as a predictive model, using this continuously-updated decay parameter. The adaptive Dynamic Matrix Controller using this model was able to control the outlet chlorine concentration quite acceptably, and further improvements of the control performance are expected from ongoing tuning. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.

Antibiotics are a group of compounds used in large quantities for both human therapy and animal food production. In recent years, antibiotics have been detected at low levels (up to μg/L) in wastewater effluents and surface waters in the US, Canada, and parts of Europe. The presence of such contaminants in the environment is of concern due to their potential to promote bacterial resistance as well as to trigger long-term adverse human health effects. Chemical disinfection, one of essential water treatment processes, may aid in their removal but may also form byproducts that can remain biologically active. Nanofiltration is another water treatment process that may provide an effective physical barrier for these contaminants. The goal of this study was to understand the effect chlorination and nanofiltration processes have on the fate of select antibiotics during water treatment, especially under varying water quality conditions. Changes in pH were found to significantly influence the reaction rate of one veterinary antibiotic, carbadox, with aqueous chlorine while also influencing the byproducts formed. The pH was also found to significantly alter the removal efficiency of several antibiotics by different nanofiltration membranes of varying pore size in which dependence was mechanistically investigated using transport models. In addition, the presence of tertiary amines was found to enhance transformation of antibiotics during chlorination. Overall, fundamental understanding regarding their fate during such water treatment processes will help industries develop better strategies for effectively controlling this emerging group of contaminants.

In model reaction systems to test amino acids in chlorinated waste effluents, several amino acids were chlorinated at high chlorine doses. (2000-4000 mg/1). Amino acids present in municipal waste effluents before and after chlorination were concentrated and purified using cation exchange and Chelex resins. After concentration and cleanup of the samples, the amino acids were derivatized by esterification of the acid functional groups and acylation of the amine groups. Identification and quantification of the amino acids and chlorination products was carried out by gas chromatography/mass spectrometry, using a digital computer data system. Analysis of the waste products revealed the presence of new carbon-chlorine bonded derivatives of the amino acid tyrosine when the effluents were treated with heavy doses of chlorine.

Disinfectants such as chlorine are used in drinking water treatment to protect the public health from pathogenic microorganisms. However, disinfectants also react with humic material present in raw water sources and produce by-products, such as trihalomethanes. Total trihalomethanes (TTHMs) include four compounds: chloroform, bromodichloromethane, dibromochloromethane and bromoform. TTHMs are carcinogenic and have been found to cause adverse pregnancy outcomes. Therefore, the United States Environmental Protection Agency (U.S. EPA) has set the maximum contaminant limit for TTHMs at 80 ìg/L. Additional regulations require reliable drinking water disinfection for resistant pathogens and treatment plants must simultaneously control TTHMs and achieve proper disinfection. Research has shown that THM formation depends on several factors. THM concentrations increase with increasing residence time, increased temperature and increased pH. The disinfectant type and concentration is also significant: THM concentrations can be minimized by using lower disinfectant doses or alternative disinfectants to chlorine such as chloramines. Chloramines are formed by the addition of both chlorine and ammonia. The Worcester Water Filtration Plant in Holden, MA currently uses both ozone and chlorine for primary disinfection. Chlorine is also used for secondary disinfection. This study analyzed the effect of using chloramines versus free chlorine on TTHM production at the plant. Water samples were collected from the plant, dosed with chlorine/chloramines and stored for their designated residence times. The residual chlorine was then quenched with sodium thiosulfate and the samples were analyzed for TTHM concentration using a GC-MS. Experiments were conducted in December of 2001, April of 2002 and February of 2003, and examined varying residence times, pH conditions, temperatures, chlorine to nitrogen ratios and free chlorine reaction periods. The study found that as the pH increased the TTHMs increased. For the free chlorine samples, as residence time increased, the TTHMs increased. For the chloramination samples it was found that most of the TTHMs were formed in the first six hour reaction period with free chlorine before ammonia was added. Therefore, reducing this free chlorine contact period to 0 or 3 hours would reduce THM formation further. Chlorine to nitrogen ratios between 3:1 and 7:1 were all effective at reducing THM concentrations. Using chloramination at a 3:1 ratio (with a 6 hour free chlorine time) reduced THM formation by approximately 38% for a 54 hour residence time compared to using free chlorine.