Economic Aspects
The comparison of the economics of anaerobic and aerobic treatment processes is presented in this chapter. Anaerobic treatment offers substantial savings in electrical power and other benefits which can result in significant savings. These savings are suf
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Economic Aspects
Abstract The comparison of the economics of anaerobic and aerobic treatment processes is presented in this chapter. Anaerobic treatment offers substantial savings in electrical power and other benefits which can result in significant savings. These savings are sufficient to offer a return on investment in many cases.
Keywords Economics Anaerobic treatment Aerobic treatment electrical power Saving in operating cost Return on investment
Savings in
Several researchers have made comparison of the economics of anaerobic and aerobic treatment processes (Habets and Knelissen 1985a, b, c; Eroglu et al. 1994; Maat 1990; Rekunen et al. 1985; Deshpande et al. 1991; Huss et al. 1986). Habets and Knelissen (1985a, b, c) have reported the economics of many full-scale UASB reactors treating effluents from the paper industry. The pay back of the plant was less than 1.5 years in one board mill. This was due to the significant cost savings from the reduced sewer-discharge levies. In one paper mill at Netherlands-Papierfabriek Roermond, the volumetric capacity of an existing aerobic plant was more than doubled by the addition of BIOPAQ pretreatment plant. Capital and operational costs for complete treatment were reduced by 23% (Habets and Knelissen 1985a). The biogas is used for steam production. Treatment costs per unit of waste treated decreases as loading rates increase. Anaerobic pretreatment before the existing activated sludge system in the SEKA Bolu Hardboard and Laminated Board (Formica) mill in Turkey provided 70% reduction both in energy for aeration and in excess biological sludge production from the treatment plant (Eroglu et al. 1994). In addition to these, it has been possible to recover bioenergy of 7690 kWh per day, corresponding to 280,000 US dollars per year by adding anaerobic pretreatment into the existing treatment system. Maat (1990) compared the costs of full-scale anaerobic treatment and aerobic treatment plants. He reported two cases. In one, the capital cost to expand the aerobic system was estimated at 2.5 times the cost for the anaerobic system. For another case, the estimated capital cost for an aerobic system was 2.0 times that for © The Author(s) 2017 P. Bajpai, Anaerobic Technology in Pulp and Paper Industry, SpringerBriefs in Applied Sciences and Technology, DOI 10.1007/978-981-10-4130-3_9
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9 Economic Aspects
Table 9.1 Cost benefit analysis of aerobic and anaerobic-aerobic treatmenta
(a) Capacity to remove BOD kg/d (200 kg BOD/ton bld.pulp)
(b) Power requirement kwh/d (1.2 kwh/kg BOD removed) (c) Nutrient chemicals – Urea (46% N) kg/d – DAP (20 N:20 P) kg/d (100 BOD:5 N:1 P) Removal ratio (d) Treated effluent quality – BOD5 20 °C mg/1 – COD mg/1 (e) BOD5 removal efficiency % (f) COD removal efficiency % (g) Biogas generation m3/d (with 70% methane content)
Conventional aerobic treatment
Anaerobic-aerobic treatment
10,000
10,000
12,000
8500 kg BOD in AN 1500 kg BOD in AE 3500 1 kwh/5 kg BOD in AN 1.2 kwh/5 kg BOD in AE
900 500
450 300 200:5:1 in AN 100:5:
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