"While actions undertaken are having an impact, we are aware the odour issue still remains and council is continuing to work hard to resolve the issue," Mrs Davidson said.
CCTV investigations of pipe work near the plant were due to completed by the end of next week, and a monitoring trailer that had been in place since June 21 had initially recorded high levels of hydrogen sulphide, but this had reduced significantly this week.
The system was being dosed with a suppressant targeting hydrogen sulphide.
Further towards town, a smell in the Northumberland St/Russell St area had been identified as coming from the stormwater sumps that, along with others prompting odour complaints, had been or were in the process of being cleaned.
Finally, leachate from the landfill would be discharged at Waipawa rather than Waipukurau until July 31, to ascertain whether this activity had contributed.
Mrs Davidson encouraged people to continue filling in the survey, so that investigations could continue.
"The council would like to thank residents for their on-going patience and understanding while we continue to resolve the odour issue."
Bruce Steedman lives directly opposite the treatment plant on Mt Herbert Rd and said he first started complaining about odours in 2015.
He said the situation appeared to have improved in the past week, and was pleased the council was addressing the problem.
"It hasn't been as bad as it was but whether that's just because the system has cooled down or the wind has changed I don't know - it's a bit early to make a judgment."