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'' ' <br />r ~~ Total Suspended Solids (TSS) <br />1 ~,~~•\' BPT guidelines previously contained limitations of 25/45 mg/1 for the 30 <br />/u~J daq average and daily maximum respectively. However, these limitations have <br />been remanded and presently no technology based limitations exist. .Numerous <br />permits have been written with the 25/45 limitations and compliance with the <br />limitations has not been a problem. <br />In moat cases settling alone is sufficient to provide compliance, althoug the <br />practice of adding settling agents is also practiced and has proven co every <br />successful, yet economical. <br />The SES limitation is specified in 10.1.4, the 30/45 as the day average <br />and 7 day average respectively. As previously discussed a vel run operation <br />should have little problems complying with these limitations ovever the <br />enforcement cost to the state can be significant Sn obtai g 3 samples in 7 <br />days or 30 days, which is necessary to demonstrate a vial ion. Therefore, a <br />60 mg/1 limitation as a daily maximum will also be requ~ ed. <br />The monitoring frequency for TSS shall be monthl This is adequate to <br />protect water quality as properly run operations s uld have no problem in <br />complying with the limitation. <br />011 and Grease <br />The state effluent standard of 10 mg/1 applicable to all discharges into <br />state waters unless supecceded by a techno ogy based Limitation. Compliance <br />vich this limitation is normally demonscr~ced by a visual inspeccion.of the <br />discharge Eor an oil sheen. Conditions ,6E noncompliance have been very <br />infrequent, and should problems occur ey will very likely be the result of <br />poor operation ar vandalism. <br />The monitoring frequency Eor this parameter in the permit will be weekly <br />and a visual analysis will be suf ~iclenc. Such a Frequency is warranted as a <br />check on operating conditions. , <br />i, <br />The pH range of 6.5-9.0 for WQS, is the effluent Limitation appropriate Eor <br />this permit. Though some stream segments in the.scace have a WQS of 6.0-9.0, a <br />sufficient number of stream`s have the more stringent limitation of 6.5-9.0 thus <br />warranting imposition of this limitation. Waters normally encountered in sand <br />and gravel operations are~at a pH of 7.0-8.0, this is substantiated by data <br />submitted In self monitoring reports Eor existing permits. Nacucal <br />groundvacers !a a few ~.ocations in the state will not be within these Limits <br />aad a facility at such a Location will very likely be considered an abnormal <br />operation and therefore required to obtain an Individual permit. <br />The monitori ~Erequency will be monthly Eor pH, the basis being co track <br />potential impacts of Sacernal or external accivicies. ,1n example of an <br />external activit of concern Ss a landfill, of which many exist in the area of <br />mining activities around the large municipalities. It is Eelc chat the impacts <br />of such accivicies would be detected vich monthly monitoring. Such monitoring <br />is not excessive as a quality pH meter can be obtained Eor under $100 and <br />calibration plus monitoring can be accomplished in less than 10 minutes. <br />- 4 - <br />