Advances in Water Treatment and Enviromental Management
Advances in Water Treatment and Enviromental Management
Advances in Water Treatment and Enviromental Management
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262 WATER TREATMENT8. THE RESULTS8.1 GeneralNo biological, bacteriological or chemical quality data were available for thestream prior to the commencement of this study. Therefore, no directcomparison of previous water quality can be made with the results of thisstudy. Also, automatic flow sensors <strong>in</strong> the stream <strong>and</strong> <strong>in</strong> the SKO were not<strong>in</strong>stalled until the autumn of 1988.Due to the quantity of <strong>in</strong>formation available from this study, this paper hasonly presented results from two sampl<strong>in</strong>g sites—one upstream (SIDLEYWOOD) <strong>and</strong> one downstream (BANCROFT ROAD) of the SKO under scrut<strong>in</strong>y.8.2 BiologyUnder the LQI system(6), all sampl<strong>in</strong>g sites must be classified accord<strong>in</strong>g totheir “habitat” before any <strong>in</strong>terpretation of the BMWP <strong>and</strong> ASPT scores iscarried out. The sampl<strong>in</strong>g po<strong>in</strong>ts along the Egerton Park Stream are classifiedas “habitat-poor riffles” <strong>and</strong>, as such, enhanced rat<strong>in</strong>gs are assigned to thiscategory s<strong>in</strong>ce this type of environment will support a poorer <strong>in</strong>vertebratecommunity even <strong>in</strong> the absence of pollution.The results from the two upstream or control sites suggest that the qualityrat<strong>in</strong>g is consistent, whereas the quality rat<strong>in</strong>g of the downstream sitesseems to fluctuate <strong>and</strong> generally improve when there is no ra<strong>in</strong>fall or stormspill events. Fig 4. shows the results from an upstream site at Sidley Wood<strong>and</strong> a down stream site at Bancroft Road.The diversity of flora is greater downstream of the overflow probably due tothe effect of the discharges. The <strong>in</strong>vertebrate data show the stream populationto be unstable <strong>and</strong>, overall, accord<strong>in</strong>g to the L<strong>in</strong>coln Quality Index, thestream itself has ma<strong>in</strong>ta<strong>in</strong>ed a poor quality s<strong>in</strong>ce the start of the study <strong>and</strong>has not deteriorated as a direct result of the spill events. Further longerterm effects will be available as the study progresses.8.3 ChemistryUrban run-off <strong>and</strong> the discharge from the SKO seem to be the ma<strong>in</strong> causativefactors <strong>in</strong> the variation of chemical quality of the stream. Consider<strong>in</strong>g twosampl<strong>in</strong>g sites, one upstream (Sidley Wood) <strong>and</strong> one downstream (BancroftRoad) of the SKO, the average value of the BOD for the study (Dec 87-May89) for each site was 2.57 <strong>and</strong> 3.89 mg/1 respectively—see Figs 5 <strong>and</strong> 6.The average value of the SS content for each site was 22 <strong>and</strong> 52mg/lrespectively—see Figs 5 <strong>and</strong> 6.Ammonia is toxic to fish <strong>and</strong> if a stream has ammonia levels of over lmg/1it is considered not suitable for fish life. The average value of ammoniacal
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