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pollutants depends on the nature of the pollutant. However, the cost of the treatment terms of electrical units (kWhm -3 ). In the case of ETP, the estimation of the price per unit (oxygen added), as the aeration is directly related to the specific energy consumption of aerators (kWhm - 3 ), tank volume 8500 m 3 and the energy consumption can be obtained from this value by using Eq. (1), Once the energy consumption has been calculated, the price of the power unit permits the price of the oxygen transfer dose to be calculated:
compositions in the form of oxides are showed in Figure 12. Sludge ash concentrates heavy metals, however, and if their concentration arises hazardous levels, the ash requires special handling [40,41]. Every tone of recovered fiber generates up to 200 kg (dry weight) of sludge of different types and up to 400 kg (dry weight) of rejects and sludge. Sludge structure analyses: The sludge generated by the biological wastewater treatment process at pH=7 and the fractured concrete specimens were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDS). The sludge is flocculating suspension liquid, which is made up of living or dead microorganism in network structure of extracellular polymeric substance, mixing some organic and inorganic. Sludge present in the form of complex floc structure. There are a lot of pore holding too much water in those floc structure. SEM image can be shown that Figure 12a, the shape of sludge is irregular loose body, which has much pore on surface filling with a number of small grains and holding a lot of floc, forming irregular structure. The sludge shows a heterogeneous morphology, as shown in Figure 12b. Its elemental composition as determined by EDS results show that the amount of carbon (12%), oxygen (25%), calcium (47.28%), chloride (1.85%) silica (4.52%) and aluminum (8.35%). The counts referred to the lowest energy 0.25 -0.5 keV. The peak at 1.5, 1.8 2.7 and 3.7 keV was assigned to Al, Si, Cl and Ca respectively. The sludge contained more silica and calcium than that of the other inorganic elements. This may be the reason for calcium and oxygen is mainly present in calcium carbonate, which is used as filler and coatings in paper board making process. Sludge macro and micro nutrient: The macro and micro elements contents of paper board industry sludge change dramatically based on the sludge source. Metals occur in sludge in various physicochemical forms, such as soluble, adsorbed, exchangeable, precipitated, organically, complexed, and residual phases. They used it to fractionate metals into the following fractions: (1) Exchangeable fraction, representing the most easily available metals, (2) Acid-soluble (carbonate bound) fraction, (3) Reducible (Fe – Mn oxide bound) fraction, (4) Oxidizable (organically+sulphide bound) fraction, and (5) Residual fraction, that is tightly bound to the silicate matrix of the sample. If heavy metals exist as loosely bound fractions, such as the
(HP)(0.746 kW/ hp)(Day) Motor efficiency (0.9)
(1)
3 4774.4 kWhm / day
Power(W)
Solid waste Generally, the paper and board manufacturing units practice recycle and reuse the treated effluent for the secondary fiber treatment process and by-products from ETP Primary sludge is generated in the clarification of process water by kidney treatments, e.g., dissolved air flotation. The sludge consists of mostly fines and fillers depending on the recovered paper being processed and it is relatively easy to dewater. Secondary sludge are often difficult to handle (due to a high microbial protein content), and such solids need to be mixed with primary sludge to permit adequate dewatering [38]. The paper and board manufacturing units about 300 kg of sludge is produced for each 1 ton of recycled paper [39]. The mechanical dewatering of paper board industry sludge is usually performed using a series of process units, such as gravity table or rotary thickener followed by a belt press or a screw press, as each process unit operates in different ranges of the total solids content. Primary and secondary sludge it is either recycled to the product: Sun dry board and composting respectively. Sludge physical and chemical properties: Sludge showed a wide range of humidity 65 ± 15. Variability depended on the method used to clarify and dewater sludge, and the presence of chemicals (polyelectrolytes) used to aid. The Proximate analysis of paper board industry sludge shown in Table 4. The main organic components of the sludge are cellulose fibers, hemicellulose, lignin and, to some extent, also organic binders and process chemicals which are all residues from the processes and enter the biological wastewater treatment plant via the process water flows circulating in the process. The chemical
0.3 0.01 0.01 0.5 0.02 0.01 0.04 0.01
ZnO PbO
SiO2 Al2O3 Fe2O3 CaO MgO LOI Na2O K2O SO3 TiO2 Mn2O3 P2O5 Cr2O3
1.4
3.1
2.4
38.8
1.1
30.1
22.3
0
10
20
30
40
50
(%) Figure 11: A chemical composition of paper board industry ETP sludge ash.
J Bioremediat Biodegrad ISSN: 2155-6199 JBRBD, an open access journal
Volume 7 • Issue 5 • 1000366
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