Water Treatment plant

vivi teo

Is that any standard for Sludge (alum) which are produced from water treatment plant?

boru05

Hey,

Can you give a bit more clarification on what exactly you're asking?

Are you asking about drinking water treatment or wastewater treatment?

And what do you mean by standard?

With a bit more info, I might be able to help.

vivi teo

Actually, I want to know is there any standard such as National Water Quality Standard (NWRS) for Sludge (sludge cake after thickening or dewatering) which are produced from drinking water treatment plant. I cant find any information from water treatment process. Most of them mentioned sludge disposal and treatment.

boru05

The opinion below is just that and does not constitute a legal opinion (I'm not a lawyer!)

I haven't looked at this stuff in a while but here goes.

I don't think potable water treatment sludge constitutes a sewage sludge as defined in Waste Management (Use of Sewage Sludge in Agriculture) Regulations S.I. 148/1998 (and 267/2001 as amended). Therefore it constitutes a waste and as such must be dealt with as per the Waste Management Act 1996 (and associated amendments and Regulations). In fact the EPA specifically stated the same in their 2003 report "The Quality of Drinking Water in Ireland - A Report for the Year 2003 with a Review of the Period 2001 – 2003".

I would imagine that the alum and ferric content of the sludge would be pretty high and may not be beneficial for reuse by itself. I assume that landfill or incineration would be the options for disposal. I think that they are considered non-hazardous wastes generally but you would need to check that.

Realistically, I would imagine that most potable water treatment plants treat the slurry generated from backwashing and clarifying as a trade effluent to the public sewerage system and they discharge accordingly.

However, I do know that the EPA recommended that for a drinking water treatment plant discharging to sewer, as long as the solids contribution from their effluent stream was less than 20% of the overall solids load on the downstream wastewater plant, then the biosolids generated from the wastewater treatment plant treating the drinking water treatment effluent can be applied to land etc. as per the usual rules.

I highly recommend googling the DEHLG's "Codes of Good Practice for the Use of Biosolids in Agriculture: Guidelines for Local Authorities and Wastewater Treatment Plant Operatives" as it has pretty comprehensive advice in regards to use and clearly outlines the applicable limits.

210

Waste sludges from modern treatment plants with means to dry the sludge would go to landfill. If the sludge is acceptable to the landfill in question then in it goes. If you ask about older treatment plants which have settlement lagoons and no process for drying sludges then generally the clean liquid from the lagoons would discharge to the local river and the settled sludge would be taken away to another site for further treatment/drying. Lack of investment has left a lot of treatment plants with pretty poor facilities for sludge treatment so operators being reluctance to talk about their systems and arrangements might suggest they are not completely comfortable with their arrangements, maby.