First flush rain collection system

RPA staff evolved and detail designed measures to contain all leachates and prevent pollution of a stream that flowed through the site. This stream is environmentally strategic and has protected areas both within and downstream of the site. This involved:

• specifying ground and hydrogeological investigation work
• using the resulting data to engineer a least cost system to intercept all the potentially contaminated ground-water without drawing water from the stream in the process.

RPA then specified a Reverse Osmosis (RO) plant complete with pre-treatment facilities to treat a wet season average of 1500m3/day of contaminated run-off;

Further to the storm water management arrangements, RPA designed an integrated effluent treatment plant to process the site’s numerous effluent streams including leachates from the waste deposit sites, the R.O. brine and other residues and effluents from handling all the other contaminated site waters;

Evaporator

RPA Effluent Treatment Plant

As a final element in the process effluent integration measures RPA designed and specified integrated facilities to return clean storm water and treated effluent back to the production areas for re-use such that the site as a whole is now a “zero effluent site”.

This means that other than for domestic sewage, there are no off-site discharges of effluents or surface waters, except during extremely wet weather, and then only water that is clean enough for discharge to the environmentally sensitive stream;

Further to the integrated management of aqueous based effluents, RPA also developed and designed a solidification process to stabilise the site’s hazardous solid waste residues;

• Designed a 100 hectare landfill adjacent to the site to receive the stabilised wastes in a manner which exploited the physical characteristics of the inerted waste so as to maximise environmental protection whilst minimising construction and operating costs;
• Managed a number of research and development programmes that resolved specific site problems and confirmed the practical application of newly developed technologies.
  

Slag tips & intercepted dirty water run-off

On-site dam for clean surface water

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