The use of waterworks sludge for the treatment of vegetable oil refinery industry wastewater

Abstract

Water treatment works using coagulation/flocculation in the process stream will generate a waste sludge. This sludge is termed as ferric, alum, or lime sludge based on which coagulant was primarily used. The works in Adana, Turkey uses ferric chloride. The potential for using this sludge for the treatment of vegetable oil refinery industry wastewater by coagulation has been investigated. The sludge acted as a coagulant and excellent oil and grease, COD and TSS removal efficiencies were obtained. The optimum conditions were a pH of 6 and a sludge dose of 1100 mg SS l(-1). The efficiency of sludge was also compared with alum and ferric chloride for the vegetable oil refinery wastewater. At doses of 1300-1900 mg SS l(-1), the sludge was as effective as ferric chloride and alum at removing oil and grease, COD, and TSS. In addition, various combinations of ferric chloride and waterworks sludge were also examined. Under the condition of 12.5 mg l(-1) fresh ferric chloride and 1000 mg SS l(-1) sludge dose, 99% oil and grease 99% TSS and 83% COD removal efficiencies were obtained.

Electrocoagulation of vegetable oil refinery wastewater using aluminum electrodes

“…Several treatment methods for vegetable oil refinery wastewater were applied such as adsorption (Sabah et al, 2007), coagulation (Azbar and Yonar, 2004;Basibuyuk and Kalat, 2004;Radoiu et al, 2004), anaerobic treatment (Saatci et al, 2003), reverse osmosis (Sridhar et al, 2002) and ultrafiltration (Mohammadi and Esmaeelifar, 2005). Treatment of palm oil refinery wastewater has also studied (Oswal et al, 2002).…”

Constructive Approaches Toward Water Treatment Works Sludge Management: An International Review of Beneficial Reuses

“…In France, it was reported that aluminium hydroxide sludge discharged to a sewer in a treatment plant has proved completely successful with phosphate removal up to 94%, at a dose ratio of 0.3 to 1 corresponding to about 3.5mmole/l of Al (Horth et al, 1994). In another study on the use of an iron based waterworks sludge as a coagulant in the treatment of vegetable oil refinery wastewater, Basibuyuk et al (2004) reported excellent removal efficiencies for oil, grease, COD and TSS at an optimum pH of 6 and sludge dose of 1,100mg SS/l. It was noted that the iron sludge was as efficient as using alum or ferric chloride, and removal was further enhanced when combined with ferric chloride at various doses.…”

“…In the practical context, alum sludge and ferric sludge refer respectively to the sludge generated when aluminium or iron salt is used as the coagulant. Only in Europe, several million tons of waterworks sludges are produced every year and this may double by next decade (Basibuyuk and Kalat, 2004), raising considerable concerns over their disposal and associated costs. In Netherlands, the total cost of disposing waterworks sludge stands at a staggering £30-£40 million as reported by Horths et al (1994), while in Ireland, a double fold increase has been predicted by the end of next decade from a current estimate of 15,000 to 18,000 t/pa of the dried solids .…”

Application of waterworks sludge in wastewater treatment plants

“…WWS production has been increasing over years because of increased production of drinking water and stringent drinking water regulations. Basibuyuk and Kalat (2004) predicted that the WWS production in Europe will double over the next decade.…”