A complex debate on what type of filters to use in a Forsyth County wastewater treatment plant came to a resolution Tuesday after commissioners weighed the numbers for nearly 90 minutes.The planned expansion of the Fowler plant’s capacity triggered the discussions about the filters between the county and its contracted operator, AECOM.The filters, commonly referred to in the industry as membranes, help separate materials in the treatment process.The commission’s vote Tuesday was 3-2 in favor of the staff recommendation to stick with the current membrane provider, General Electric. Patrick Bell and Brian Tam were opposed.The county’s nearly 22-year contract with AECOM, penned in 2002, laid out terms for responsibility of the plant expansion costs and purchasing infrastructure.Forsyth will contribute about $946,000 to the additional two phases.And if it stays with the current GE Zenon membranes, there’s no additional cost, said Nick Cooper of AECOM.