Removal of carbon and nutrients from domestic wastewater using a low investment, integrated treatment concept

• Published in: Water research (Oxford) 2004-07, Vol.38 (13), p.3031-3042
• Main Authors: Aiyuk, Sunny, Amoako, Joyce, Raskin, Lutgarde, van Haandel, Adrianus, Verstraete, Willy
• Format: Article
• Language: English
• Subjects: Anaerobic treatment; Applied sciences; Biological and medical sciences; Biological treatment of waters; Bioreactors; Biotechnology; Carbon - isolation & purification; CEPT pretreatment; Domestic wastewater; Environment and pollution; Exact sciences and technology; Flocculation; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; LIST; Nitrogen - isolation & purification; Other wastewaters; Phosphorus - isolation & purification; Pollution; Sewage - chemistry; UASB; Waste Disposal, Fluid - methods; Wastewaters; Water treatment and pollution; Zeolite; Zeolites - chemistry
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2004.04.040

An integrated chemical–physical–biological treatment concept for the low-cost treatment of domestic wastewater is proposed. Domestic wastewater was subjected to a chemically enhanced primary treatment (CEPT), followed by treatment in an upflow anaerobic sludge blanket (UASB) reactor. In addition, a regenerable zeolite was used to remove NH 4 +, either after CEPT pretreatment or after biological treatment in the UASB reactor. The CEPT pretreatment consisted of the addition of a coagulant (FeCl 3) and an anionic organic flocculant and removed on average 73% of the total chemical oxygen demand (COD t), 85% of the total suspended solids, and 80% of PO 4 3− present in the wastewater. The UASB system, which consequently received a low COD t input of approximately 140 mg/L, was operated using a volumetric loading rate of 0.4 g COD t/L. d (hydraulic retention time [HRT]=10 h) and 0.7 g COD t/L. d (HRT=5 h). For these conditions, the system removed about 55% of the COD t in its influent, thus producing an effluent with a low COD t of approximately 50 mg/L. The zeolite, when applied in batch mode before the UASB reactor, removed approximately 45% of the NH 4 +, whereas its application as a post-treatment cartridge resulted in almost 100% NH 4 + removal. The simple design and relatively low operating costs, due to low costs of added chemicals and low energy input (estimated at € 0.07–0.1 per m 3 wastewater treated), combined with excellent treatment performance, means that this system can be used as a novel domestic wastewater treatment system for developing countries. Therefore, the system is called a Low Investment Sewage Treatment (LIST) system.