Accelerated seeded precipitation pre-treatment of municipal wastewater to reduce scaling.
نویسندگان
چکیده
Membrane based treatment processes are very effective in removing salt from wastewater, but are hindered by calcium scale deposit formation. This study investigates the feasibility of removing calcium from treated sewage wastewater using accelerated seeded precipitation. The rate of calcium removal was measured during bench scale batch mode seeded precipitation experiments at pH 9.5 using various quantities of calcium carbonate as seed material. The results indicate that accelerated seeded precipitation may be a feasible option for the decrease of calcium in reverse osmosis concentrate streams during the desalination of treated sewage wastewater for irrigation purposes, promising decreased incidence of scaling and the option to control the sodium adsorption ratio and nutritional properties of the desalted water. It was found that accelerated seeded precipitation of calcium from treated sewage wastewater was largely ineffective if carried out without pre-treatment of the wastewater. Evidence was presented that suggests that phosphate may be a major interfering substance for the seeded precipitation of calcium from this type of wastewater. A pH adjustment to 9.5 followed by a 1-h equilibration period was found to be an effective pre-treatment for the removal of interferences. Calcium carbonate seed addition at 10 g l(-1) to wastewater that had been pre-treated in this way was found to result in calcium precipitation from supersaturated level at 60 mg l(-1) to saturated level at 5 mg l(-1). Approximately 90% reduction of the calcium level occurred 5 min after seed addition. A further 10% reduction was achieved 30 min after seed addition.
منابع مشابه
Control of mineral scale deposition in cooling systems using secondary-treated municipal wastewater.
Secondary-treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. A prominent challenge for the successful use of MWW for cooling is potentially severe mineral deposition (scaling) on pipe surfaces. In this study, theoretical, laboratory, and field work was conducted to evaluate the mineral deposition po...
متن کاملMANAGEMENT of PHOSPHORUS REMOVAL in MUNICIPAL WASTEWATER TREATMENT PLANTS
As a result of uncontrolled discharge of wastewaters containing high levels of phosphorus to the receiving bodies could create adverse effects on water quality. Therefore phosphorus should be eliminated prior to discharging into aquatic environment together with carbon and nitrogen to reduce eutrophication risk. Control of effluent phosphorus level by enhanced biological methods became a standa...
متن کاملRemoval of High Concentrations of Sulfate from Wastewater: Evaluating Different Methods and Proposing the Best Option
Background: Industrial wastewaters containing high amounts of compounds such as sulfate can cause serious risks to human health and environment. Therefore, proposing practical solutions with the lowest cost and the highest efficiency for pollutants removal is of special importance. The purpose of this study is to find a suitable method for treatment wastewater containing very high amounts of...
متن کاملBERNAL and RESTREPO Key issues for decentralization in municipal wastewater treatment
The pressure on water resources caused by accelerated urbanization, the inadequate management and disposal of wastewater and the implementation of sophisticated treatment systems which sometimes with low efficiency and coverage are some of the problems to be solved with alternative and innovative strategies that be in harmony with the recent trends on water management. One of these strategies i...
متن کاملModeling and Optimization of Phosphate Recovery from Industrial Wastewater and Precipitation of Solid Fertilizer using Experimental Design Methodology
Phosphorus (P) is one of the primary nutrients generating eutrophication in aquatic systems1. To prevent eutrophication, municipal or agricultural wastewaters are treated to reduce the phosphorus concentrations in the wastewater reaching surface water streams. While unregulated P is a pollutant in a water body, phosphorous is a useful resource in agricultural fertilizers, food supply, and indus...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemosphere
دوره 72 2 شماره
صفحات -
تاریخ انتشار 2008