Citation: Rajkumar K (2016) $Q(YDOXDWLRQRI%LRORJLFDO$SSURDFKIRUWKH(IÀXHQW7UHDWPHQWRI3DSHU%RDUGV,QGXVWU\$Q(FRQRPLF3HUVSHFWLYH J %LRUHPHGLDW%LRGHJUDG 366 GRL 366
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as high as 400 and 2500 mg/L, respectively. The BOD and COD levels of influent wastewater varied from 80-240 mg/L and 545-1817 mg/L respectively. Whereas the BOD and COD levels of effluent varied from 16.5-6.4 mg/L and 54.1-156 mg/L respectively. Figures 9 and 10 clearly shows that the levels of BOD and COD values show that the removal percentage is 91.27- 95.60% and 77.04 - 94.05% respectively. These show that very high removal efficiency can be obtained both for BOD and COD removal. These reduced to certain extent due to biological treatment process for which the effluent is treated which consists of equalization, primary clarifier, aeration tank, secondary clarifier, tertiary clariflocculator and MGF. Biological treatment process results in oxidation of organic matter, which provides energy for microbial metabolic process. It could be argued that there are two critical operational aspects of an activated sludge plant; maintaining a proper control of the dissolved oxygen (DO) concentration in the aeration tank and maintaining a good settling sludge. After observing the results the reduction obtained in case of BOD, and COD, were 93.7 and 88.3% respectively with 79 Sludge Volume Index (SVI). Total dissolved solids and total suspended solids: High amounts of dissolved solids that are commonly known as TDS. The biological treatment process cannot reduce TDS to any significant extent and the efficiency of the system can be greatly affected by high TDS [34]. The major portions of such solids are inorganic and present mostly in ionic form. Nowadays, removal of dissolved solids from industrial wastewater is a challenging job for the environmental engineers. Inorganic components of dissolved solids are more difficult to remove by biological processes. Membrane separation (ultra-filtration) [35,36] or reverse-osmosis [37] are the treatment technologies that can be employed for TDS removal. Total Dissolved Solids were also alarmingly high in treated effluent, crossing the 2,100 mg/L limit set by the Indian regulatory authorities (Table 2). Table 2 shows the total dissolved solids concentration from inlet 1599 mg/L whereas from treated effluent 1946 mg/L respectively. TDS is also one of the often-neglected parameters, even though it can have tremendous effects on the overall quality of water. In this site especially TDS control purpose installed tertiary treatment for ultra-filtration (UF) followed by reverse-osmosis (RO). Membrane treatment in paper board industry serves to optimize loop closure and therefore helps to reduce fresh water intake as well as wastewater treatment.
board industry effluents are usually low compared to municipal sewage. Nitrogen and Phosphorus are the essential elements other than the carbon for the proper growth and activity of the microorganism present in the aeration chamber [25]. Pulp and paper industrial effluent is rich in carbon source due the raw material used but, wastewater is deficient in N and P [26]. For effective treatment of wastewater, significant quantity of N and P must be added because micro-organisms present in the effluent require N and P to produce enzymes for the degradation of organic matter present. These observations are in close agreement with other’s findings [27,28]. Insufficient N can result in filamentous and dispersed growth of microbial population which settles poorly. As a general rule the ratio of N and P required with respect to BOD load is 100 BOD :5 N :1 P. Although nitrogen limitation has been reported as an important factor in inducing ligninolytic activity and ligninase production in several white rot fungi [29,30]. Sludge Volume Index (SVI): The sludge produced in physical– chemical treatments is due to the organic matter and total solids in suspension that are removed and the compounds formed with the coagulants used, since practically all of the latter become part of the sludge solids. In general, the amount and characteristics of the sludge produced during the coagulation process depend on the coagulants used and on the operating conditions. Sludge settleability was determined by measuring the SVI, which is the volume of MLSS after 30 min of settling. The SVI in coagulation process is generally governed by three factors: high polymer effect, osmotic pressure effect and hydration effect [31]. The SVIs measured throughout the study and its important parameter for the treatment of wastewater. SVI is used to assess the settling qualities of sludge and minimum and maximum values were 52 and 109 respectively (Figure 8). It is reported in literature that SVI can vary from 30-400 mL/L [32]. But it is also mentioned that if the value increased from 150 mL/L the plant operator should face the problem of sludge bulking [33]. BOD and COD removal: Aerobic treatment currently use on site biological treatment. There are numerous biological treatment systems available, the most common being the activated sludge process. BOD and COD the pulping process plays a central role in the pollution load and composition of the wastewater produced by the pulp and paper mills [4]. SFT house liquors contain high amounts of chemicals, lignin, residual fibres, etc., which result in increased levels of BOD and COD
CAT- SVI
EAT- SVI
100 120
0 20 40 60 80
1 3 5 7 9 1113151719212325272931 Days
Figure 8: Variation in the SVI characteristics of the activated sludge produced in the treatment of paper board industry wastewater for the period of study.
J Bioremediat Biodegrad ISSN: 2155-6199 JBRBD, an open access journal
Volume 7 • Issue 5 • 1000366
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